2-(hetero)aryl-benzimidazole and imidazopyridine derivatives as inhibitors of asparagime emethyl transferase
09856252 ยท 2018-01-02
Assignee
Inventors
- Paul Anthony Stupple (Bundoora, AU)
- Scott Raymond Walker (Parkville, AU)
- Jo-Anne Pinson (Parkville, AU)
- Helen Rachel Lagiakos (Parkville, AU)
- Gillian Elizabeth Lunniss (Parkville, AU)
- Ian Peter Holmes (Bundoora, AU)
- Alexandra Elizabeth Stupple (Parkville, AU)
- Ylva Elisabet Bergman (Parkville, AU)
- Richard Charles Foitzik (Parkville, AU)
- Wilhelmus Johannes Antonius Kersten (Bundoora, AU)
- Michelle Ang Camerino (Parkville, AU)
Cpc classification
A61P7/00
HUMAN NECESSITIES
C07D519/00
CHEMISTRY; METALLURGY
C07D235/18
CHEMISTRY; METALLURGY
A61P35/00
HUMAN NECESSITIES
International classification
C07D413/00
CHEMISTRY; METALLURGY
C07D519/00
CHEMISTRY; METALLURGY
C07D513/02
CHEMISTRY; METALLURGY
C07D235/18
CHEMISTRY; METALLURGY
C07D401/00
CHEMISTRY; METALLURGY
Abstract
Substituted benzimidazole and 3H-imidazo[4,5-b]pyridines or formula I: where X and Y respectively are selected from: (i) N and N; and (ii) N and CR.sup.4; A.sup.2 is selected from: a C.sub.5 heteroarylene group, containing 2 or 3 ring heteroatoms, where the bonds to L1 and the core are to one another; L.sup.1 is selected from: (i) .sup.A1OCH.sub.2.sup.A2; (ii) .sup.A1CH.sub.2O.sup.A2; (iii) .sup.A1C(O)NH.sup.A2; (iv) .sup.A1CH(OH).sup.A2; (v) .sup.A1CH.sub.2NHC(O).sup.A2; (vi) .sup.A1SCH.sub.2.sup.A2; (vii) .sup.A1CH.sub.2S.sup.A2; (viii) .sup.A1CH.sub.2.sup.A2; and (ix) .sup.A1CH(CH.sub.3)O.sup.A2; A1 is phenyl, optionally substituted by F or CF.sub.3; their use as pharmaceuticals, and in particular, in treating cancer and hemoglobinopathies. ##STR00001##
Claims
1. A compound of formula I: ##STR00168## wherein: A.sup.2 is selected from: ##STR00169## where R.sup.5 is selected from H, Br, F, methyl, OMe, carboxy, C.sub.1-4 alkyl ester, carboxamide, C.sub.5-7 N-containing heteroaryl group, which is optionally substituted by a C.sub.1-4 alkyl group; (ii) a C.sub.5 heteroarylene group, containing 2 or 3 ring heteroatoms, where the bonds to L1 and the core are to one another; L.sup.1 is selected from: (i) .sup.A1OCH.sub.2.sup.A2; (ii) .sup.A1CH.sub.2O.sup.A2; (iii) .sup.A1C(O)NH.sup.A2; (iv) .sup.A1CH.sub.2S.sup.A2; (v) .sup.A1CH.sub.2.sup.A2; and (vi) .sup.A1CH(CH.sub.3)O.sup.A2; A.sup.1 is phenyl, optionally substituted by F or CF.sub.3; (a) one of R.sup.2 and R.sup.3 is L.sup.2-A.sup.3, where L.sup.2 is selected from the group consisting of: a single bond, CH.sub.2, O, NH, NMe, NHCH.sub.2, and NMe-CH.sub.2; and A.sup.3 is selected from: (i) a C.sub.5-10 non-aromatic N-containing heterocyclic group, which is optionally substituted by one or two groups selected from OH, NH.sub.2, CH.sub.2N(R.sup.6).sub.2, C.sub.1-4 alkyl, C.sub.1-4 alkylacyl, C.sub.1-4 alkyl ester, oxo and C.sub.1-4 alkyl sulfonyl, where each R.sup.6 is independently selected from H, C.sub.1-4 alkyl, C.sub.1-4 alkylacyl and C.sub.1-4 alkyl ester; and (ii) a C.sub.5-7 non-aromatic, non-N-containing heterocyclic group; (b) R.sup.1 is selected from: (i) H; (ii) Halo; (c) the other one of R.sup.2 and R.sup.3 is H.
2. A compound according to claim 1, wherein L.sup.1 is selected from: (i) .sup.A1OCH.sub.2.sup.A2; (ii) .sup.A1CH.sub.2O.sup.A2; and (iii) .sup.A1C(O)NH.sup.A2.
3. A compound according to claim 1, wherein L.sup.1 is selected from: (vi) A.sup.1-SCH.sub.2-A.sup.2; (vii) A.sup.1-CH.sub.2-A.sup.2; and (viii) A.sup.1-CH(CH.sub.3)O-A.sup.2.
4. A compound according to claim 1, wherein A.sup.1 is unsubstituted phenyl.
5. A compound according to claim 1, wherein A.sup.2 is: ##STR00170##
6. A compound according to claim 5, wherein R.sup.5 is H.
7. A compound according to claim 1, wherein L.sup.2 is selected from the group consisting of: a single bond, O, NH, NHCH.sub.2, and NMe-CH.sub.2.
8. A compound according to claim 7, wherein L.sup.2 is selected from the group consisting of: a single bond, O and NH.
9. A compound according to claim 8, wherein L.sup.2 is a single bond.
10. A compound according to claim 7, wherein A.sup.3 is a non-aromatic C.sub.5-10 N-containing heterocyclic group, which is optionally substituted by one or two groups selected from OH, NH.sub.2, CH.sub.2NH.sub.2, C.sub.1-4 alkyl, C.sub.1-4 alkylacyl, C.sub.1-4 alkyl ester, oxo and C.sub.1-4 alkyl sulfonyl.
11. A compound according to claim 10, wherein the C.sub.5-7 N-containing heterocyclic group is selected from piperidinyl, tetrahydropyridinyl, morpholino, thiomorpholino (including oxidized forms thereof) and piperazinyl.
12. A compound according to claim 1, wherein R.sup.3 is L.sup.2-A.sup.3, where A.sup.3 is piperidinyl or piperazinyl, and L.sup.2 is selected from a single bond, O, NH, NMe-, CH.sub.2 and NHCH.sub.2.
13. A compound according to claim 1 which is selected from the group consisting of: 2-(4-(phenoxymethyl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (9); 1-(4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidin-1-yl)ethanone (10); 6-(1-methylpiperidin-4-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (11); 2-(4-(benzyloxy)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (12); 1-(4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidin-1-yl)ethanone (13); 6-(piperidin-4-yl)-2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridine (14); tert-butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (15); 2-(4-(phenoxymethyl)phenyl)-6-(piperidin-3-yl)-3H-imidazo[4,5-b]pyridine (16); 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yloxy)-3H-imidazo[4,5-b]pyridine (18); 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)morpholine (19); 1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (21); 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine (23); 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 1-oxide (24); 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 1,1-dioxide (25); 2-(4-(benzyloxy)phenyl)-5-(4-methylpiperazin-1-yl)-3H-imidazo[4,5-b]pyridine (26); 2-(4-(benzyloxy)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (27); tert-butyl ((1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-3-yl)methyl)carbamate (28); tert-butyl 2-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (29); tert-butyl 3-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)(methyl)amino)piperidine-1-carboxylate (30); tert-butyl 4-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (31); tert-butyl 4-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)piperidine-1-carboxylate (32); 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (33); tert-butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (34); 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-3-yl)-3H-imidazo[4,5-b]pyridine (35); tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (39); 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (40); 7-chloro-2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-1H-imidazo[4,5-b]pyridine (42); 2-(4-(benzyloxy)phenyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine (45); (R)-2-amino-1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)propan-1-one (46); 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (47); (1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-3-yl)methanamine (50); 2-(4-(benzyloxy)phenyl)-N-(piperidin-2-ylmethyl)-3H-imidazo[4,5-b]pyridin-5-amine (51); 2-(4-(benzyloxy)phenyl)-N-(piperidin-4-ylmethyl)-3H-imidazo[4,5-b]pyridin-5-amine (52); 2-(4-(benzyloxy)phenyl)-N-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-5-amine (53); 1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-4-amine (54); (1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-4-yl)methanamine (55); 5-(piperazin-1-yl)-2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridine (56); 2-(4-((2-fluorobenzyl)oxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (57); 2-(4-((3-fluorobenzyl)oxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (58); 2-(4-((4-fluorobenzyl)oxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (59); 5-(piperazin-1-yl)-2-(4-((2-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridine (60); 2-(4-(1-phenylethoxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (61); 2-(4-(benzyloxy)-3-bromophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (62); 2-(4-(benzyloxy)-3-(1-methyl-1H-pyrazol-4-yl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (63); 2-(4-(benzyloxy)-3-(pyridin-3-yl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (64); 2-(4-(benzyloxy)-3-fluorophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (65)); methyl 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoate dihydrogen chloride salt (66); 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid dihydrochloride salt (67); 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzamide dihydrogen chloride salt (68); 2-(4-(benzyloxy)-3-(1-methyl-1H-pyrazol-4-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (69); 2-(4-(Benzyloxy)-3-(1H-pyrazol-5-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (70); 2-(4-(Benzyloxy)-3-(pyridin-3-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (71); 2-(4-(Benzyloxy)-3-(pyrimidin-5-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (72); 2-(4-(benzyloxy)-3-(1H-pyrazol-4-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (73); 2-(4-(benzyloxy)-3-methylphenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (74); 2-(4-(benzyloxy)-3-methoxyphenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4, 5-b]pyridine (75); 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-ylmethyl)-3H-imidazo[4,5-b]pyridine (79); 2-(4-(benzyloxy)phenyl)-6-(1-(methylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (83); or tert-butyl 4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (84); 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (85); 5-(1-methylpiperidin-4-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (86); 2-(4-(benzyloxy)phenyl)-5-(1-(methylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (87); ethyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (88); 2-(4-(benzyloxy)phenyl)-5-(1-(cyclopropylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (89); 2-(4-(benzyloxy)phenyl)-5-(1-(ethylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (90); 2-(4-(benzyloxy)phenyl)-5-(4-(methylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (91); 2-(4-(benzyloxy)phenyl)-5-(4-(cyclopropylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (92); 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)-N-methylacetamide (93); tert-butyl 4-(2-(4-(benzylthio)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (95); 2-(4-(benzylthio)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (96); 2-(4-(benzyloxy)phenyl)-5-(1-(ethylsulfonyl)-1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine (97); 1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3,6-dihydropyridin-1(2H)-yl)ethan-1-one (98); 5-(1-methylpiperidin-3-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (99); 2-(4-(benzyloxy)phenyl)-6-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (100); 1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-4-methylpiperidin-4-ol (101); 2-(phenoxymethyl)-4-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)thiazole (102); 7-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (103); and 2-(1-benzyl-1H-pyrazol-4-yl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (104).
14. A compound according to claim 8, wherein A.sup.3 is a non-aromatic C.sub.5-10 N-containing heterocyclic group, which is optionally substituted by one or two groups selected from OH, NH.sub.2, CH.sub.2NH.sub.2, C.sub.1-4 alkyl, C.sub.1-4 alkylacyl, C.sub.1-4 alkyl ester, oxo and C.sub.1-4 alkyl sulfonyl.
15. A compound according to claim 9, wherein A.sup.3 is a non-aromatic C.sub.5-10 N-containing heterocyclic group, which is optionally substituted by one or two groups selected from OH, NH.sub.2, CH.sub.2NH.sub.2, C.sub.1-4 alkyl, C.sub.1-4 alkylacyl, C.sub.1-4 alkyl ester, oxo and C.sub.1-4 alkyl sulfonyl.
16. A pharmaceutical composition comprising a compound according to claim 1, and a pharmaceutically acceptable excipient.
Description
EXAMPLES
(1) The following are examples are provided solely to illustrate the present invention and are not intended to limit the scope of the invention, as described herein.
ACRONYMS
(2) For convenience, many chemical moieties are represented using well known abbreviations, including but not limited to, methyl (Me), ethyl (Et), n-propyl (nPr), isopropyl (iPr), n-butyl (nBu), tert-butyl (tBu), n-hexyl (nHex), cyclohexyl (cHex), phenyl (Ph), biphenyl (biPh), benzyl (Bn), naphthyl (naph), methoxy (MeO), ethoxy (EtO), benzoyl (Bz), and acetyl (Ac).
(3) For convenience, many chemical compounds are represented using well known abbreviations, including but not limited to, methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH), ether or diethyl ether (Et.sub.2O), acetic acid (AcOH), acetonitrile (MeCN), dichloromethane (methylene chloride, DCM), trifluoroacetic acid (TFA), dimethylformamide (DMF), tetrahydrofuran (THF), dimethylsulfoxide (DMSO), meta-chloroperoxybenzoic acid (mCPBA), 1,1-bis(diphenylphosphino)ferrocene (dppf), 2-dicyclohexylphosphino-2,6-diisopropoxybiphenyl (Ruphos), tert-butyloxycarbonyl (Boc), 2-(trimethylsilyl)ethoxymethyl (SEM), 2-(1H-7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDCI), 4-dimethylaminopyridine (DMAP), N,N-diisopropylethylamine (DIPEA), lithium bis(trimethylsilyl)amide (LiHMDS) and 1-hydroxybenzotriazole (HOBt), Tetrabutylammonium bromide (TBAB), Chloro-(2-dicyclohexylphosphino-2,6-diisopropoxy-1,1-biphenyl)[2-(2-aminoethyl)phenyl]palladium(II)-methyl-t-butyl ether adduct (RuPhos palladacycle precatalyst), Lithium bis(trimethylsilyl)amide (LiHMDS), Bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane adduct (DABAL-AIMe.sub.3), 2-Dicyclohexylphosphino-2,4,6-triisopropylbiphenyl (XPhos), dimethoxyethane (DME).
(4) General Experimental Details
(5) Unless otherwise stated the following generalizations apply. .sup.1NMR spectra were recorded on either a Bruker Avance DRX300 (300 MHz) or a Bruker Ultrashield plus (400 MHz). The multiplicity of a signal is designated by the following abbreviations: s, singlet; d, doublet; t, triplet; q, quartet; dd, doublet of doublets; dt, doublet of triplets; tt, triplet of triplets; br, broad; m, multiplet. All observed coupling constants, J, are reported in Hertz.
(6) Analytical LC/MS data was generated using an Agilent 1200 Series LC coupled to an Agilent 6100 Series Single Quad MS (LCMS-A) or an Agilent 1260 Infinity LC coupled to a 6100 series Single Quad MS (LCMS-B). Preparative mass-directed HPLC was carried out using a Waters ZQ 3100.
(7) LCMS Method A (LCMS-A)
(8) Instrument: Agilent 6100 Series Single Quad LC/MS
(9) Agilent 1200 Series HPLC
(10) Pump: 1200 Series G1311A Quaternary pump
(11) Autosampler: 1200 Series G1329A Thermostatted Autosampler
(12) Detector: 1200 Series G1314B Variable Wavelength Detector
(13) LC Conditions:
(14) Reverse Phase HPLC analysis
(15) Column: Luna C.sub.8(2) 5 u 504.6 mm 100 A
(16) Column temperature: 30 C.
(17) Injection Volume: 5 L
(18) Solvent A: Water 0.1% Formic Acid
(19) Solvent B: Acetonitrile 0.1% Formic Acid
(20) Gradient: 5-100% B over 10 min
(21) Detection: 254 nm or 214 nm
(22) MS Conditions:
(23) Ion Source: Quadrupole
(24) Ion Mode: Multimode-ES
(25) Drying gas temp: 300 C.
(26) Vaporizer temperature: 200 C.
(27) Capillary voltage (V): 2000 (positive)
(28) Capillary voltage (V): 4000 (negative)
(29) Scan Range: 100-1000
(30) Step size: 0.1 sec
(31) Acquisition time: 10 min
(32) LCMS Method B (LCMS-B)
(33) Instrument:
(34) Pump: 1260 Infinity G1312B Binary pump
(35) Autosampler: 1260 Infinity G1367E 1260 HiP ALS
(36) Detector: 1290 Infinity G4212A 1290 DAD
(37) LC Conditions:
(38) Reverse Phase HPLC analysis
(39) Column: Poroshell 120 EC-C18
(40) Column temperature: 35 C.
(41) Injection Volume: 1 L
(42) Solvent A: Water 0.1% Formic Acid
(43) Solvent B: Acetonitrile 0.1% Formic Acid
(44) Gradient: 5-100% B over 3.8 mins
(45) Detection: monitored at 254 nm and 214 nm
(46) MS Conditions:
(47) Ion Source: Quadrupole
(48) Ion Mode: API-ES
(49) Drying gas temp: 350 C.
(50) Capillary voltage (V): 3000 (positive)
(51) Capillary voltage (V): 3000 (negative)
(52) Scan Range: 100-1000
(53) Step size: 0.1 sec
(54) Acquisition time: 5 min
(55) LCMS Method C (LCMS-C)
(56) Instrument: Waters ZQ 3100 Mass Detector
(57) Waters 2545-Pump
(58) Waters SFO System Fluidics Organizer
(59) Waters 2996 Diode Array Detector
(60) Waters 2767 Sample Manager
(61) LC Conditions:
(62) Reverse Phase HPLC analysis
(63) Column: XBridge C18 5 m 4.6100 mm
(64) Injection Volume: 10 L
(65) Solvent A: Water 0.1% Formic Acid
(66) Solvent B: Acetonitrile 0.1% Formic Acid
(67) Gradient: 10-100% B over 10 minutes
(68) Flow rate: 1.5 ml/min
(69) Detection: 100-600 nm
(70) MS Conditions
(71) Ion Source: Single-quadrupole
(72) Ion Mode: ES positive
(73) Source Temp: 150 C.
(74) Desolvation Temp: 350 C.
(75) Detection: Ion counting
(76) Capillary (KV): 3.00
(77) Cone (V): 30
(78) Extractor (V): 3
(79) RF Lens (V): 0.1
(80) Scan Range: 100-1000 Amu
(81) Scan Time: 0.5 sec
(82) Acquisition time: 10 minutes
(83) Gas Flow: 100 L/hr
(84) Desolvation: 650 L/hr
(85) Preparative Mass-Directed HPLC
(86) Instrument:
(87) Waters ZQ 3100-Mass Detector
(88) Waters 2545-Pump
(89) Waters SFO System Fluidics Organizer
(90) Waters 2996 Diode Array Detector
(91) Waters 2767 Sample Manager
(92) LC Conditions:
(93) Reverse Phase HPLC analysis
(94) Column: XBridge C18 5 m 1950 mm
(95) Injection Volume 500 L
(96) Solvent A: Water 0.1% Formic Acid
(97) Solvent B: Acetonitrile 0.1% Formic Acid
(98) Gradient: 25-100% B over 10 min
(99) Flow rate: 19 mL/min
(100) Detection: 100-600 nm
(101) MS Conditions:
(102) Ion Source: Single-quadrupole
(103) Ion Mode: ES positive
(104) Source Temp: 150 C.
(105) Desolvation Temp: 350 C.
(106) Detection: Ion counting
(107) Capillary (KV)-3.00
(108) Cone (V): 30
(109) Extractor (V): 3
(110) RF Lens (V): 0.1
(111) Scan Range: 100-1000 Amu
(112) Scan Time: 0.5 sec
(113) Acquisition time: 10 min
(114) Gas Flow
(115) Desolvation L/hour-650
(116) Cone L/hour-100
(117) Analytical thin-layer chromatography was performed on Merck silica gel 60 F254 aluminium-backed plates which were visualised using fluorescence quenching under UV light or acidic anisaldehyde or a basic KMnO.sub.4 dip. Flash chromatography was performed on a Biotage Isolera purification system using either Grace or Biotage silica cartridges. Microwave irradiation was achieved using a CEM Explorer SP Microwave Reactor. Anhydrous solvents were purchased from Sigma-Aldrich and used where necessary. Other solvents were used as supplied from Merck KGaA. Molecular sieves were activated by heating under vacuum. Biotage Isolute phase separation cartridges were used for cartridge based phase separations. Extractions on SCX cartridges were performed with Varian Bond Elut SCX solid phase extraction cartridges.
Example 1: Synthesis of 2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (1)
(118) ##STR00043##
a) Methyl 4-(phenoxymethyl)benzoate (A3)
(119) Methyl 4-(bromomethyl)benzoate A2 (0.400 g, 1.75 mmol), DMF (10 mL), phenol A1 (0.181 g, 1.92 mmol) and Cs.sub.2CO.sub.3 (0.853 g, 2.62 mmol) were stirred at room temperature for 18 hours. The mixture was poured into water (200 mL), stood for 20 minutes and filtered. The collected precipitate was air-dried followed by drying under high vacuum to give the title compound A3 as a white solid (0.386 g, 91%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.98 (d, J=8.3 Hz, 2H), 7.59 (d, J=8.4 Hz, 2H), 7.34-7.26 (m, 2H), 7.05-6.99 (m, 2H), 6.98-6.92 (m, 1H), 5.20 (s, 2H), 3.85 (s, 3H). LCMS-A rt 6.25 min, m/z (positive ion) 243.1 [M+H].sup.+.
b) 4-(Phenoxymethyl)benzoic acid (A4)
(120) Methyl 4-(phenoxymethyl)benzoate A3 (0.382 g, 1.58 mmol) was dissolved in THF (12 mL); water (2 mL), MeOH (1 mL) and lithium hydroxide monohydrate (0.264 g, 6.31 mmol) were added. The reaction was stirred at room temperature for 20 hours then poured into 2 M aqueous HCl (200 mL). The solid was stood for 15 minutes and the solid collected by filtration. The collected solid was washed with 1 M aqueous HCl and water, then air-dried followed by drying under high vacuum to give the title compound A4 as a white solid (0.285 g, 79%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.96 (d, J=8.3 Hz, 2H), 7.56 (d, J=8.3 Hz, 2H), 7.34-7.25 (m, 2H), 7.02 (d, J=7.8 Hz, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.19 (s, 2H). OH proton not observed. LCMS-A rt 5.71 min.
c) 2-(4-(Phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (1)
(121) 4-(Phenoxymethyl)benzoic acid A4 (50 mg, 0.22 mmol), HOBt (36 mg, 0.26 mmol), EDCI (50 mg, 0.26 mmol), pyridine-2,3-diamine A5 (25 mg, 0.23 mmol), DMF (1 mL) and DIPEA (0.092 mL, 0.53 mmol) were stirred together at room temperature for 19 hours. The solution was added to water (20 mL), stood for twenty minutes and filtered. The collected solid (52 mg) was dissolved in glacial acetic acid (1 mL) and heated in the microwave (140 C./1 hour). The cooled mixture was concentrated in vacuo, the residue partitioned between EtOAc (25 mL) and 1 M pH 7 potassium phosphate buffer (25 mL). The aqueous phase was extracted with EtOAc (225 mL), and the combined EtOAc extracts dried over Na.sub.2SO.sub.4 and concentrated in vacuo. Column chromatography (4 g silica cartridge, 0-10% MeOH/DCM) gave the title compound as a white solid (32 mg, 48%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.69-13.04 (m, 1H), 8.34 (s, 1H), 8.25 (d, J=8.2 Hz, 2H), 8.03 (s, 1H), 7.64 (d, J=8.1 Hz, 2H), 7.34-7.28 (m, 2H), 7.25 (dd, J=8.0, 4.8 Hz, 1H), 7.05 (d, J=8.0 Hz, 2H), 6.96 (t, J=7.3 Hz, 1H), 5.20 (s, 2H). LCMS-A rt: 5.25 min; m/z (positive ion): 302.2 [M+H].sup.+; m/z (negative ion) 301.1 [MH].sup..
Example 2: Synthesis of 2-(4-(benzyloxy)phenyl)-1H-imidazo[4,5-b]pyridine (2)
(122) ##STR00044##
a) 4-(Benzyloxy)benzaldehyde (A8)
(123) Benzyl bromide A6 (9.9 mL, 83 mmol) was added to a suspension of 4-hydroxybenzaldehyde A7 (10.0 g, 81.9 mmol) and K.sub.2CO.sub.3 (17.0 g, 122 mmol) in acetonitrile (100 mL). The resulting mixture was stirred vigorously at room temperature for 5 hours. The suspension was filtered and the collected solids were washed with acetonitrile (220 mL). The combined filtrates were concentrated in vacuo to give a solid residue which was suspended in petroleum benzine 40-60 C. (100 mL). The solid was collected via filtration, washed with petroleum benzine 40-60 C. (200 mL) and air dried to give the title compound (16 g, 92%) as a white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 9.89 (s, 1H), 7.87-7.82 (m, 2H), 7.48-7.34 (m, 5H), 7.12-7.06 (m, 2H), 5.16 (s, 2H).
b) 2-(4-(Benzyloxy)phenyl)-1H-imidazo[4,5-b]pyridine (2)
(124) A solution of 2-amino-3-nitropyridine A9 (0.066 g, 0.47 mmol) and 4-(benzyloxy)benzaldehyde A8 (0.10 g, 0.47 mmol) in DMSO (5 mL) was treated with 1 M aqueous Na.sub.2S.sub.2O.sub.4 (1.4 mL, 1.4 mmol). The reaction mixture was heated to 70 C. for 25 hours then cooled to room temperature and treated dropwise with 5 M aqueous NH.sub.4OH (1 mL). A light yellow precipitate was immediately formed, which was then collected by filtration, washed with water (210 mL) and dried under reduced pressure to give a light yellow solid. This was purified by silica gel chromatography (25 g silica cartridge, 0-10% MeOH in DCM) followed by preparative mass-directed HPLC to give the title compound (0.022 g, 15%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.30 (s, 1H), 8.42-7.83 (m, 4H), 7.73-6.94 (m, 8H), 5.21 (s, 2H). LCMS-A rt 4.72, m/z (positive ion) 302.2 [M+H].sup.+, m/z (negative ion) 300.0 [MH].sup..
Example 3: Synthesis of N-(4-(3H-imidazo[4,5-b]pyridin-2-yl)phenyl)benzamide (3)
(125) ##STR00045##
a) Methyl 4-benzamidobenzoate (A12)
(126) To a suspension of methyl 4-aminobenzoate A11 (0.600 g, 3.97 mmol) in anhydrous DCM (10 mL) at 0 C. under N.sub.2 was added DIPEA (0.761 mL, 0.564 mmol) followed by benzoyl chloride A10 (0.507 mL, 4.37 mmol). The cooling bath was removed and the reaction was stirred overnight, then diluted with DCM (50 mL) and washed with aqueous HCl (2 M, 250 mL). The organic phase was dried (MgSO.sub.4) and concentrated in vacuo to give the title compound (1.00 g, 99%) as a white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.07-8.04 (m, 2H), 8.03 (br s, 1H), 7.90-7.84 (m, 2H), 7.77-7.72 (m, 2H), 7.61-7.54 (m, 1H), 7.53-7.47 (m, 2H), 3.91 (s, 3H). LCMS-A rt 5.31 min, m/z (positive ion) 256.2 [M+H].sup.+, m/z (negative ion) 254.1 [MH].sup..
b) 4-Benzamidobenzoic acid (A13)
(127) To a solution of methyl 4-benzamidobenzoate A12 (1.00 g, 3.92 mmol) in 4:1:1 v/v THF/MeOH/water (30 mL) was added LiOHH.sub.2O (0.505 g, 11.8 mmol). The solution was stirred at room temperature for 17 hours and then acidified with 1 M aqueous HCl. The precipitate was collected by filtration to give the title compound (0.886 g, 94%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 10.54 (br s, 1H), 8.00-7.88 (m, 6H), 7.65-7.59 (m, 1H), 7.59-7.51 (m, 2H). LCMS-A rt 4.84 min, m/z (positive ion) 242.1 [M+H].sup.+, m/z (negative ion) 240.1 [MH].sup..
c) N-(4-(3H-Imidazo[4,5-b]pyridin-2-yl)phenyl)benzamide (3)
(128) 4-Benzamidobenzoic acid A13 (0.10 g, 0.42 mmol), HOBt (0.067 g, 0.50 mmol), EDCI (0.095 g, 0.50 mmol), pyridine-2,3-diamine A5 (0.047 g, 0.46 mmol), DMF (2 mL) and DIPEA (0.17 mL, 1.0 mmol) were stirred together at room temperature for 19 hours. The solution was added to water (15 mL), stood for twenty minutes and filtered. The collected solid was dissolved in glacial acetic acid (3.0 mL) and heated in the microwave twice (140 C. for 1 hour, then 140 C. for 30 minutes). The cooled mixture was concentrated in vacuo, the residue partitioned between EtOAc (50 mL) and 1 M pH 7 potassium phosphate buffer (50 mL). The aqueous phase was extracted with EtOAc (225 mL), and the combined EtOAc extracts dried (MgSO.sub.4) and concentrated in vacuo. The product was purified twice by silica gel chromatography (12 g silica cartridge, 50-100% EtOAc in petroleum benzine 40-60 C., then 12 g silica cartridge, 60-70% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.025 g, 19%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.35 (brs, 1H) 10.51 (s, 1H), 8.31 (d, J=3.9 Hz, 1H), 8.22 (d, J=8.8 Hz, 2H), 8.04-7.93 (m, 4H), 7.65-7.60 (m, 1H), 7.60-7.53 (m, 2H), 7.22 (dd, J=7.9, 4.8 Hz, 1H). One NH proton not observed. LCMS-A rt 4.40 min, m/z (positive ion) 315.2 [M+H].sup.+, m/z (negative ion) 313.1 [MH].sup..
Example 4: Synthesis of 2-(4-(benzyloxy)phenyl)-7-chloro-3H-imidazo[4,5-b]pyridine (4)
(129) ##STR00046##
a) 4-Chloropyridine-2,3-diamine (A15)
(130) Iron powder (1.126 g, 20.17 mmol) followed by NH.sub.4Cl (1.079 g, 20.17 mmol) were added to a stirred suspension of 2-amino-4-chloro-3-nitropyridine A14 (0.700 g, 4.03 mmol) in i-PrOH (30 mL) and water (15 mL) at room temperature. The reaction was heated to 70 C. and stirred at this temperature for 2 hours. The reaction was cooled and filtered through a plug of celite which was washed with EtOAc (150 mL). The filtrate was washed with saturated aqueous NaHCO.sub.3 (100 mL), brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.555 g, 96%) as a brown solid. LCMS-A rt 1.34 min, m/z (positive ion) 144.1, 146.2 [M+H].sup.+.
b) (E)-N3-(4-(Benzyloxy)benzylidene)-4-chloropyridine-2,3-diamine (A16)
(131) 4-Chloropyridine-2,3-diamine A15 (0.555 g, 3.87 mmol) and 4-(benzyloxy)benzaldehyde A8 (0.861 g, 4.06 mmol) were suspended in water (40 mL) and the reaction mixture was then heated at reflux for 22 hours. The reaction mixture was cooled and the water was evaporated in vacuo to give a brown solid. The crude material was purified by silica gel chromatography (40 g silica cartridge, 0-75% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.305 g, 23%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 9.17 (s, 1H), 8.13-8.05 (m, 2H), 7.62 (d, J=5.1 Hz, 1H), 7.52-7.45 (m, 2H), 7.45-7.38 (m, 2H), 7.39-7.30 (m, 1H), 7.20 (d, J=5.1 Hz, 1H), 7.16 (d, J=8.8 Hz, 2H), 5.61 (s, 2H), 5.22 (s, 2H). LCMS-A m/z (positive ion) 338.1, 340.1 [M+H].sup.+ No UV trace for product.
c) 2-(4-(Benzyloxy)phenyl)-7-chloro-3H-imidazo[4,5-b]pyridine (4)
(132) (Diacetoxyiodo)benzene (0.436 g, 1.35 mmol) was added to a solution of (E)-N.sup.3-(4-(benzyloxy)benzylidene)-4-chloropyridine-2,3-diamine A16 (0.305 g, 0.903 mmol) in dry THF (12 mL) under an atmosphere of nitrogen. The reaction was stirred for 3 hours at room temperature, then concentrated in vacuo and diluted with EtOAc (150 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL). The combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product. The material was purified by silica gel chromatography (40 g silica cartridge, 0-100% EtOAc in cyclohexane, then 0-10% MeOH in DCM) to give the title compound (0.131 g, 43%) as a brown solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.72 (s, 1H), 8.33-8.17 (m, 3H), 7.54-7.45 (m, 2H), 7.46-7.39 (m, 2H), 7.38-7.31 (m, 2H), 7.22 (d, J=8.8 Hz, 2H), 5.22 (s, 2H). LC-MS-A rt 6.29 min, m/z (positive ion) 336.1, 338.1 [M+H].sup.+.
Example 5: Synthesis of 2-(4-(benzyloxy)phenyl)-7-methyl-3H-imidazo[4,5-b]pyridine (5)
(133) ##STR00047##
(134) To a suspension of 4-(benzyloxy)benzaldehyde A8 (0.076 g, 0.36 mmol) and 4-methyl-3-nitropyridin-2-amine A17 (0.050 g, 0.33 mmol) in EtOH (2.0 mL) was added 1 M Na.sub.2S.sub.2O.sub.4 solution (0.980 mL, 0.980 mmol). The resulting yellow suspension was irradiated in a microwave reactor at 110 C. for 15 minutes. The reaction was cooled to room temperature, then 28% w/w aqueous NH.sub.3 (1 mL) was added and the reaction mixture was stirred for 5 minutes. The solution was filtered to give a yellow solid which was purified by silica gel chromatography (12 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.014 g, 14%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO): 13.16 (br s, 1H), 8.18 (d, J=8.8 Hz, 2H), 8.14 (d, J=4.9 Hz, 1H), 7.52-7.47 (m, 2H), 7.46-7.38 (m, 2H), 7.39-7.31 (m, 1H), 7.20 (d, J=9.0 Hz, 2H), 7.02 (d, J=4.9 Hz, 1H), 5.21 (s, 2H), 2.58 (s, 3H). LCMS-B rt 3.09 min, m/z (positive ion) 316.2 [M+H].sup.+.
Example 6: Synthesis of 7-methyl-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (6)
(135) ##STR00048##
a) 1-Bromo-4-(phenoxymethyl)benzene (A19)
(136) Phenol A1 (1.76 g, 18.7 mmol), DMF (50 mL), Cs.sub.2CO.sub.3 (6.647 g, 20.4 mmol) and 1-bromo-4-(bromomethyl)benzene A18 (4.429 g, 17.0 mmol) were stirred at room temperature. After 17 hours the mixture was diluted with water (200 mL) and stirred for a further hour. The mixture was filtered, the collected solid washed with water (200 mL) and air dried to give the title compound (3.975 g, 89%) as a white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.55-7.48 (m, 2H), 7.33-7.27 (m, 4H), 7.01-6.92 (m, 3H), 5.02 (s, 2H). LCMS-A: rt 6.59 min; no product ions detected.
b) 4-(Phenoxymethyl)benzaldehyde (A20)
(137) 1-Bromo-4-(phenoxymethyl)benzene A19 (350 mg, 1.33 mmol) in THF (10 mL) was cooled to 78 C. under nitrogen, and n-butyllithium (1.5 M solution, 1.33 mL, 2.0 mmol) was added. After 30 minutes, DMF (1.03 mL, 13.3 mmol) was added and the mixture stirred at 78 C. for one hour. The cooling bath was removed and the mixture allowed to come to room temperature. The mixture was quenched with 1 M HCl (5 mL) and concentrated on a rotary evaporator. The aqueous residue was diluted with water (20 mL) and extracted with chloroform (220 mL). The combined chloroform extracts were washed with water (320 mL), brine (20 mL), dried over Na.sub.2SO.sub.4 and evaporated. Column chromatography (12 g silica cartridge, 0-100% chloroform/hexane) gave the title compound (198 mg, 70%) as a white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 10.03 (s, 1H), 7.93-7.88 (m, 2H), 7.61 (d, J=8.1 Hz, 2H), 7.34-7.27 (m, 2H), 7.02-6.95 (m, 3H), 5.16 (s, 2H). LCMS-A rt 6.61 min; no product ions detected.
c) 4-Methylpyridine-2,3-diamine (A21)
(138) Iron powder (0.365 g, 6.53 mmol) and NH.sub.4Cl (0.349 g, 6.53 mmol) were added to a stirred suspension of 4-methyl-3-nitropyridin-2-amine A17 (0.200 g, 1.31 mmol) in i-PrOH (10 mL) and water (5 mL). The reaction was heated to 70 C. and stirred for 2 hours. The reaction was then cooled and filtered through a plug of celite, which was washed with EtOAc (75 mL). The filtrate was washed with saturated aqueous NaHCO.sub.3 (75 mL), brine (75 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.060 g, 37%) as a dark purple solid. .sup.1H NMR (400 MHz, CDCl.sub.3): 7.55 (d, J=5.1 Hz, 1H), 6.53 (d, J=5.1 Hz, 1H), 4.19 (br s, 2H), 3.26 (brs, 2H), 2.16 (s, 3H). LCMS-B: rt 0.74 min, m/z (positive ion) 124.1 [M+H].sup.+.
d) 7-Methyl-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (6)
(139) A solution of 4-methylpyridine-2,3-diamine A21 (0.060 g, 0.49 mmol) and 4-(phenoxymethyl)benzaldehyde A20 (0.114 g, 0.556 mmol) in MeOH (6 mL) was irradiated in a microwave reactor for 20 minutes at 110 C., then 20 minutes at 130 C. and finally 60 minutes at 130 C. The MeOH was evaporated in vacuo and the resulting gum was dissolved in THF (6 mL). (Diacetoxyiodo)benzene (0.204 g, 0.633 mmol) was added and the reaction stirred under an atmosphere of nitrogen for 3 hours. The reaction was concentrated, then diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL). The combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (12 g silica Cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH in EtOAc) to give the title compound (0.011 g, 7%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO): 13.40 (br s, 1H), 8.26 (d, J=8.3 Hz, 2H), 8.19 (d, J=4.8 Hz, 1H), 7.63 (d, J=7.9 Hz, 2H), 7.31 (tt, J=7.4, 2.3 Hz, 2H), 7.08-7.02 (m, 3H), 6.96 (tt, J=7.2, 1.0 Hz, 1H), 5.20 (s, 2H), 2.60 (s, 3H). LCMS-B: rt 3.08 min, m/z (positive ion) 316.2 [M+H].sup.+.
Example 7: Synthesis of 2-(4-(benzyloxy)phenyl)-7-methoxy-3H-imidazo[4,5-b]pyridine (7)
(140) ##STR00049##
a) 4-Methoxy-3-nitropyridin-2-amine (A23)
(141) 4-Chloro-3-nitropyridin-2-amine A14 (0.600 g, 3.46 mmol) was dissolved in dry MeOH (40 mL) under an atmosphere of nitrogen and NaOMe (0.467 g, 8.64 mmol) was added. The reaction was heated at reflux for 18 hours, cooled and quenched with water (5 mL) and then concentrated in vacuo. The resulting residue was diluted with EtOAc (150 mL) and saturated aqueous NaHCO.sub.3 (100 mL), the layers were separated and the aqueous layer was extracted with EtOAc (2100 mL). The combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (40 g silica cartridge, 0-100% EtOAc in cyclohexane) to give the title compound (0.457 g, 78%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.04 (d, J=5.8 Hz, 1H), 6.90 (s, 2H), 6.51 (d, J=5.8 Hz, 1H), 3.87 (s, 3H). LCMS-B rt 1.82 min, m/z (positive ion) 170.1 [M+H].sup.+.
b) 4-Methoxypyridine-2,3-diamine (A24)
(142) Iron powder (0.751 g, 13.5 mmol) followed by NH.sub.4Cl (0.719 g, 13.5 mmol) were added to a stirred suspension of 4-methoxy-3-nitropyridin-2-amine A23 (0.455 g, 2.69 mmol) in isopropanol (20 mL) and water (10 mL) at room temperature. The reaction was heated to 70 C. and stirred at this temperature for 2 hours then cooled and filtered through a plug of celite which was washed with EtOAc (100 mL). The filtrate was washed with saturated aqueous NaHCO.sub.3 (100 mL), brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.143 g, 38%) as a purple solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.30 (d, J=5.7 Hz, 1H), 6.31 (d, J=5.7 Hz, 1H), 5.23 (s, 2H), 4.06 (s, 2H), 3.76 (s, 3H). LCMS-B rt 0.65 min, m/z (positive ion) 140.2 [M+H].sup.+.
c) 2-(4-(Benzyloxy)phenyl)-7-methoxy-3H-imidazo[4,5-b]pyridine (7)
(143) 4-Methoxypyridine-2,3-diamine A24 (0.070 g, 0.50 mmol) and 4-(benzyloxy)benzaldehyde A8 (0.117 g, 0.55 mmol) were dissolved in MeOH (6 mL) and heated in the microwave for 20 minutes at 110 C. then 30 minutes at 130 C. and finally 60 minutes at 140 C. The MeOH was evaporated in vacuo and the resulting gum was dissolved in THF (6 mL). (Diacetoxyiodo)benzene (0.211 g, 0.654 mmol) was added and the mixture was stirred under an atmosphere of nitrogen at room temperature for 20 hours. The reaction was concentrated and diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL), the layers were separated and the aqueous layer was extracted with EtOAc (100 mL). The combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (12 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-15% MeOH in EtOAc) to give the title compound (0.035 g, 21%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.26 (br s, 1H), 8.15 (d, J=7.8 Hz, 3H), 7.51-7.45 (m, 2H), 7.44-7.38 (m, 2H), 7.38-7.32 (m, 1H), 7.20-7.15 (m, 2H), 6.82 (d, J=5.5 Hz, 1H), 5.20 (s, 2H), 4.05 (s, 3H). LCMS-A rt 4.82 min, m/z (positive ion) 332.2 [M+H].sup.+.
Example 8: Synthesis of 2-(4-(benzyloxy)phenyl)-7-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (8)
(144) ##STR00050##
a) tert-Butyl 2-amino-3-nitro-5,6-dihydro-[4,4-bipyridine]-1 (2H)-carboxylate (A27)
(145) An aqueous solution of 2 M Na.sub.2CO.sub.3 (3.44 mL, 6.88 mmol) was added to a degassed mixture of tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1 (2H)-carboxylate A26 (1.42 g, 4.59 mmol), 2-amino-4-bromo-3-nitropyridine A25 (0.500 g, 2.29 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (0.080 g, 0.12 mmol) in 1,4-dioxane (30 mL). The reaction mixture was stirred at 80-90 C. for 20 hours. The resulting mixture was concentrated in vacuo and partitioned between EtOAc (50 mL) and water (30 mL), then filtered through a pad of Celite. The layers were separated and the aqueous layer was extracted with EtOAc (15 mL). The combined organic layers were washed with 1:1 water: saturated brine (30 mL), dried (MgSO.sub.4), filtered and concentrated in vacuo. The residue was purified by column chromatography (silica cartridge, 0-80% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.583 g, 79%) as a bright yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.15 (d, J=4.9 Hz, 1H), 7.23-6.93 (s, 2H), 6.54 (d, J=4.9 Hz, 1H), 5.68 (s, 1H), 3.97-3.75 (m, 2H), 3.58-3.40 (t, J=5.5 Hz, 2H), 2.29-2.14 (td, J=5.5, 2.5 Hz, 2H), 1.42 (s, 9H), LCMS-A rt 5.51 min, m/z (positive ion) 321 [M+H].sup.+.
b) tert-Butyl 4-(2, 3-diaminopyridin-4-yl)piperidine-1-carboxylate (A28)
(146) A suspension of tert-butyl 2-amino-3-nitro-5,6-dihydro-[4,4-bipyridine]-1(2H)-carboxylate A27 (400 mg, 1.25 mmol) and 10% Pd/C (54% water wet, 12.5 mg Pd) in 96% EtOH (125 mL) and EtOAc (125 mL) was stirred under hydrogen (5 bar) for 22 hours. The reaction mixture was filtered through celilte and washed with EtOH (30 mL) and the resulting solution was concentrated in vacuo. The residue was dissolved in EtOAc and filtered through celite again. The filtrate was concentrated in vacuo to give the title compound (340 mg, 93%) as a light brown solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.25 (d, J=5.3 Hz, 1H), 6.30 (d, J=5.3 Hz, 1H), 5.28 (s, 2H), 4.48 (s, 2H), 4.12-4.00 (m, 2H), 2.96-2.69 (m, 2H), 1.67 (d, J=12.8 Hz, 2H), 1.41 (s, 9H+1H hidden underneath), 1.36-1.27 (m, 2H), LCMS-A rt 4.30 min; m/z (positive ion) 293 [M+H].sup.+.
c) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)piperidine-1-carboxylate (A29)
(147) 4-(Benzyloxy)benzaldehyde A8 (66.0 mg, 0.31 mmol) and tert-butyl 4-(2,3-diaminopyridin-4-yl)piperidine-1-carboxylate A28 (100 mg, 0.342 mmol) were heated at reflux in water (1 mL) for 17 hours. A brown solid formed and was collected by filtration, the solid was washed with water (3 mL) and then dissolved in DCM (10 mL), dried (MgSO.sub.4) and filtered. The filtrate was concentrated in vacuo and the residue dissolved in DCM (2 mL), PhI(OAc).sub.2 (100 mg, 0.311 mmol) was added and the reaction was stirred for one hour. The mixture was concentrated in vacuo and the residue dissolved in MeOH (2 mL). The solution was loaded onto an SCX cartridge (10 g) which was eluted with MeOH (310 mL) then 9:1 MeOH:aqueous ammonia (310 mL). Fractions containing product were combined and concentrated to dryness and the resulting material was purified by chromatography (25 g silica cartridge, 1% MeOH in CHCl.sub.3). Fractions containing impure material were concentrated and further purified by column chromatography (silica cartridge; 15%-100% EtOAc in petroleum benzine 40-60 C.). The fractions containing pure material from both columns were combined and concentrated in vacuo to give the title compound (9.3 mg, 6%) as a pale yellow powder; LCMS-A 5.33 min, m/z (positive ion) 485 [M+H].sup.+ m/z (negative ion) 483 [MH].sup.+.
d) 2-(4-(Benzyloxy)phenyl)-7-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (8)
(148) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)piperidine-1-carboxylate A29 (9.3 mg, 0.019 mmol) in CDCl.sub.3 (1 mL) was treated with TFA (37 L). The solution was stirred for 2 hours and 1 M aqueous NaOH (1 mL) was added and the layers separated. The aqueous layer was extracted with CHCl.sub.3 (25 mL), the combined organic layers were washed with 1:1 water: saturated brine (10 mL) dried (MgSO.sub.4) and filtered. The reaction had not gone to completion by TLC. The organic layer was treated with TFA (1 mL) and stirred overnight. 1 M NaOH (5 mL) was added and the resulting precipitate was collected by vacuum filtration. The solid was dissolved in chloroform and evaporated to dryness to give the title compound (3.4 mg, 46%) as a pale golden coloured solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.55 (d, J=5.1 Hz, 1H), 7.38 (dt, J=8.8, 3.2 Hz, 2H), 6.68 (s, 2H), 6.65-6.57 (m, 2H), 6.58-6.53 (s, 1H), 6.53-6.47 (s, 1H), 6.49-6.39 (m, 2H), 4.43 (s, 2H), 3.04-2.75 (m, 4H), 1H obscured by solvent peaks, 1.54-1.45 (m, 2H) 1.54-1.45 (m, 2H). NH protons not observed. LCMS-A rt 4.21 min, m/z (positive ion) 385 [M+H].sup.+.
Example 9: Synthesis of 2-(4-(phenoxymethyl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (9)
(149) ##STR00051##
a) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[3, 4-bipyridine]-1(2H)-carboxylate (A31)
(150) 5-Bromo-3-nitropyridin-2-amine A30 (2.50 g, 11.5 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (3.90 g, 12.6 mmol) and PdCl.sub.2(dppf) DCM solvate (474 mg, 5 mol %) were loaded into a flask, the flask was sealed and flushed with nitrogen. Dioxane (100 mL) was added, followed by a solution of K.sub.2CO.sub.3 (4.76 g, 34.4 mmol) in water (50 mL). The mixture was degassed with three vacuum/nitrogen cycles, heated to 80 C. for 16 hours, and allowed to cool. The mixture was concentrated, the aqueous residue diluted with water (400 mL) and chloroform (250 mL). The aqueous phase was extracted with chloroform (2150 mL), the combined chloroform extracts washed with brine (200 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. Column chromatography (0-80% EtOAc/hexanes) gave the title compound (3.058 g, 83%) as a yellow-orange solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.45 (d, J=2.3 Hz, 1H), 8.37 (d, J=2.2 Hz, 1H), 6.73 (br s, 2H), 6.06 (s, 1H), 4.13-4.04 (m, 2H), 3.65 (t, J=5.7 Hz, 2H), 2.48 (s, 2H), 1.49 (s, 9H). LCMS-A: rt 5.58 min; m/z (positive ion) 321.2 [M+H].sup.+, 265.1 [M-tBu+2H].sup.+.
b) tert-Butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate (A32)
(151) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[3,4-bipyridine]-1(2H)-carboxylate A31 (3.05 g, 9.52 mmol), 10% Pd/C (50% wet with water, 1.5 g), EtOAc (200 mL) and 96% EtOH (200 mL) were stirred under hydrogen at a pressure of 4 bar. After 16 hours the mixture was filtered through celite, and the celite washed with 96% EtOH (400 mL). The combined filtrates were evaporated, and the syrupy residue suspended in toluene and the mixture concentrated in vacuo. The residue was suspended in diethyl ether and the mixture concentrated in vacuo to give the title compound (2.76 g, 99%) as a brown solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.49 (d, J=1.7 Hz, 1H), 6.73 (d, J=1.8 Hz, 1H), 4.20 (br, 4H), 3.39 (br, 2H), 2.76 (t, J=11.9 Hz, 2H), 2.50 (tt, J=12.1, 3.4 Hz, 1H), 1.75 (d, J=12.9 Hz, 2H), 1.60-1.48 (m, 2H), 1.47 (s, 9H). LCMS-A: rt 4.22 min; m/z (positive ion) 293.3 [M+H].sup.+.
c) tert-Butyl 4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A33
(152) tert-Butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (250 mg, 0.86 mmol), 4-(phenoxymethyl)benzaldehyde A20 (181 mg, 0.86 mmol), activated 3 molecular sieves (2 mm beads, 500 mg) and MeOH (5 mL) were stirred at 60 C. After 18 hours the mixture was decanted from the molecular sieves, the sieves washed with MeOH (5 mL) and the combined MeOH solutions concentrated in vacuo. The residue was dissolved in THF (5 mL), PhI(OAc).sub.2 (303 mg, 0.94 mmol) was added and the mixture stirred for two hours. The solvent was removed in vacuo, the residue partitioned between water (25 mL) and EtOAc (25 mL). The aqueous phase was extracted with further EtOAc (225 mL), the combined EtOAc phases washed with brine (50 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. Column chromatography (12 g silica cartridge, 0-100% EtOAc/petroleum benzine 40-60 C.) gave the title compound (200 mg, 48%) as a yellow solid .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.35 (br s, 1H), 8.26 (d, J=1.8 Hz, 1H), 8.23 (d, J=8.3 Hz, 2H), 7.85 (s, 1H), 7.63 (d, J=8.3 Hz, 2H), 7.34-7.28 (m, 2H), 7.07-7.02 (m, 2H), 6.99-6.92 (m, 1H), 5.20 (s, 2H), 4.11 (d, J=12.0 Hz, 2H), 2.93-2.74 (m, 3H), 1.82 (d, J=12.5 Hz, 2H), 1.61 (qd, J=12.5, 4.1 Hz, 2H), 1.43 (s, 9H). LCMS-A: 6.24 min; m/z (positive ion) 485.3 [M+H].sup.+; m/z (negative ion) 483.3 [MH].sup..
d) 2-(4-(Phenoxymethyl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (9)
(153) tert-Butyl 4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A33 (200 mg, 0.41 mmol), DCM (8 mL) and TFA (2 mL) were stirred at room temperature for 18 hours. The mixture was quenched with 20% w/v aqueous NaOH (20 mL) and the volatile solvents removed in vacuo. The aqueous residue was diluted with water (30 mL) and the aqueous phase was extracted with EtOAc (350 mL), the combined organic extracts washed with brine (50 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to give the title compound (160 mg, quant) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.26-8.19 (m, 3H), 7.81 (s, 1H), 7.63 (d, J=8.3 Hz, 2H), 7.34-7.27 (m, 2H), 7.04 (d, J=7.8 Hz, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.20 (s, 2H), 3.07 (d, J=12.0 Hz, 2H), 2.81-2.72 (m, 1H), 2.69-2.59 (m, 2H), 1.81-1.72 (m, 2H), 1.62 (qd, J=12.3, 3.9 Hz, 2H). LCMS-A: rt 4.64 min; m/z (positive ion): 385.2 [M+H].sup.+; m/z (negative ion): 383.2 [MH].sup..
Example 10: Synthesis of 1-(4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidin-1-yl)ethanone (10)
(154) ##STR00052##
1-(4-(2-(4-(Phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidin-1-yl)ethanone (10)
(155) 2-(4-(Phenoxymethyl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 9 (0.070 g, 0.182 mmol) was dissolved in DCM (7 mL) under an atmosphere of nitrogen and DIPEA (0.095 mL, 0.546 mmol) followed by acetyl chloride (0.019 mL, 0.273 mmol) were added and the resulting mixture was stirred at room temperature for 20 hours. The reaction mixture was diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL), the layers were separated and the aqueous layer was extracted with EtOAc (70 mL). The combined organic layers were washed with water (70 mL), brine (70 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.070 g, 90%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.32 (brs, 1H), 8.29-8.18 (m, 3H), 7.84 (s, 1H), 7.63 (d, J=8.0 Hz, 2H), 7.36-7.24 (m, 2H), 7.07-6.99 (m, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.20 (s, 2H), 4.62-4.52 (m, 1H), 3.99-3.91 (m, 1H), 3.16 (td, J=13.4, 13.0, 2.6 Hz, 1H), 2.95 (tt, J=12.2, 3.5 Hz, 1H), 2.62 (td, J=13.1, 2.8 Hz, 1H), 2.05 (s, 3H), 1.91-1.79 (m, 2H), 1.71 (qd, J=12.7, 4.2 Hz, 1H), 1.56 (qd, J=12.7, 4.3 Hz, 1H). LCMS-A rt 5.28 min; m/z (positive ion) 427.2 [M+H].sup.+.
Example 11: Synthesis of 6-(1-methylpiperidin-4-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (11)
(156) ##STR00053##
6-(1-Methylpiperidin-4-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (11)
(157) To a solution of 2-(4-(phenoxymethyl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 9 (0.009 g, 0.023 mmol) in anhydrous MeOH (2 mL) was added a 37% aqueous solution of formaldehyde (0.005 mL, 0.070 mmol) under an atmosphere of nitrogen followed by NaBH(OAc).sub.3 (0.020 g, 0.094 mmol) and the reaction was stirred at room temperature for 18 hours. Volatiles were removed in vacuo and the residue was diluted with EtOAc (20 mL) and saturated aqueous NaHCO.sub.3 (20 mL), the layers were separated and the aqueous layer was extracted with EtOAc (20 mL). The combined organic layers were washed with brine (30 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a gum which was dissolved in DCM (1 mL) and concentrated in vacuo to give the title compound (0.008 g, 80%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.30 (brs, 1H), 8.28-8.17 (m, 3H), 7.84 (s, 1H), 7.66-7.57 (m, 2H), 7.36-7.27 (m, 2H), 7.08-7.01 (m, 2H), 6.95 (tt, J=7.2, 1.0 Hz, 1H), 5.20 (s, 2H), 2.93-2.85 (m, 2H), 2.70-2.57 (m, 1H), 2.21 (s, 3H), 2.04-1.95 (m, 2H), 1.84-1.71 (m, 4H). LCMS-A rt 4.64 min; m/z (positive ion) 399.2 [M+H].sup.+.
Example 12: Synthesis of 2-(4-(benzyloxy)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (12)
(158) ##STR00054##
a) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A34)
(159) 4-(Benzyloxy)benzaldehyde A8 (0.200 g, 0.942 mmol) and tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (0.276 g, 0.942 mmol) were dissolved in MeOH (10 mL) and activated 3 sieves (0.500 g) were added. The reaction mixture was heated at reflux for 3 days. The resulting suspension was cooled to room temperature, decanted from the sieves and the solvent was removed in vacuo. Tetrahydrofuran (10 mL) followed by (Diacetoxyiodo)benzene (0.364 g, 1.131 mmol) were added under an atmosphere of nitrogen and the reaction was stirred at room temperature for 2 hours. The reaction was concentrated in vacuo and diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL), the combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (40 g silica Cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.210 g, 46%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.16 (br s, 1H), 8.25-8.09 (m, 3H), 7.80 (s, 1H), 7.52-7.29 (m, 5H), 7.27-7.14 (m, 2H), 5.21 (s, 2H), 4.11 (d, J=12.3 Hz, 2H), 2.93-2.72 (m, 3H), 1.82 (d, J=12.3 Hz, 2H), 1.61 (qd, J=12.5, 4.3 Hz, 2H), 1.43 (s, 9H). LCMS-A rt 5.91 min, m/z (positive ion) 485.3 [M+H].sup.+.
b) 2-(4-(Benzyloxy)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (12)
(160) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A34 (0.205 g, 0.423 mmol) was dissolved in DCM (15 mL) under an atmosphere of nitrogen and trifluoroacetic acid (0.972 mL, 12.7 mmol) was added and the resulting mixture was stirred at room temperature for 20 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (100 mL) and 2 M aqueous NaOH (100 mL), the layers were separated and the aqueous layer was extracted with EtOAc (70 mL), the combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.142 g, 87%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.24-8.11 (m, 3H), 7.75 (s, 1H), 7.52-7.47 (m, 2H), 7.45-7.32 (m, 3H), 7.24-7.14 (m, 2H), 5.21 (s, 2H), 3.08-2.99 (m, 2H), 2.78-2.69 (m, 1H), 2.61 (td, J=12.0, 2.4 Hz, 2H), 1.78-1.69 (m, 2H), 1.60 (qd, J=12.1, 4.1 Hz, 2H). NH protons not observed. LCMS-A rt 4.56 min, m/z (positive ion) 385.2 [M+H].sup.+.
Example 13: 1-(4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidin-1-yl)ethanone (13)
(161) ##STR00055##
(162) tert-Butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (530 mg, 1.81 mmol), 4-(benzyloxy)benzoic acid A38 (414 mg, 1.81 mmol), MeCN (10 mL), DIPEA (0.947 mL, 5.44 mmol) and HATU (758 mg, 1.99 mmol) were stirred at room temperature for 19 hours. The mixture was poured into water (100 mL) and extracted with EtOAc (3100 mL). The combined EtOAc phases were washed with brine (100 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. The residue was dissolved in acetic acid (20 mL) and heated in the microwave (140 C./1 hour). The cooled mixture was concentrated in vacuo, the residue dissolved in MeOH and applied to a 10 g SCX cartridge. The cartridge was eluted with MeOH (150 mL), followed by elution with 95:5 MeOH: concentrated aqueous ammonia (100 mL). The basic eluent was concentrated, and the residue concentrated in vacuo twice from absolute EtOH. Column chromatography (12 g silica cartridge, 0-20% MeOH/DCM) and collection of the major product containing fractions gave a yellow solid. The solid was suspended in ether (10 mL), the solvent decanted and the remaining solid dried under vacuum to give the title compound (151 mg, 20%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.19 (br s, 1H), 8.22 (d, J=1.6 Hz, 1H), 8.17-8.12 (m, 2H), 7.79 (s, 1H), 7.51-7.46 (m, 2H), 7.45-7.38 (m, 2H), 7.38-7.32 (m, 1H), 7.23-7.17 (m, 2H), 5.21 (s, 2H), 4.61-4.53 (m, 1H), 3.99-3.91 (m, 1H), 3.20-3.11 (m, 1H), 2.93 (tt, J=12.0, 3.3 Hz, 1H), 2.66-2.56 (m, 1H), 2.05 (s, 3H), 1.90-1.79 (m, 2H), 1.70 (qd, J=12.6, 4.1 Hz, 1H), 1.55 (qd, J=12.6, 4.2 Hz, 1H). LCMS-A: 4.79 min; m/z (positive ion) 427.3 [M+H].sup.+; m/z (negative ion): 425.1 [MH].sup..
Example 14: Synthesis of 6-(piperidin-4-yl)-2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridine (14)
(163) ##STR00056##
a) 4-((4-(Trifluoromethyl)benzyl)oxy)benzaldehyde (A40)
(164) 1-(Bromomethyl)-4-(trifluoromethyl)benzene (2.50 g, 10.4 mmol) was added to a suspension of 4-hydroxybenzaldehyde A7 (1.25 g, 10.2 mmol) and K.sub.2CO.sub.3 (2.12 g, 15.4 mmol) in acetonitrile (50 mL). The resulting mixture was stirred at room temperature for 18 hours. After this time, the suspension was filtered and the collected solids washed with acetonitrile (40 mL). The combined filtrates were evaporated in vacuo to give a solid residue which was suspended in petroleum benzine 40-60 C. (100 mL), the solid was collected via filtration, washed with petroleum benzine 40-60 C. (50 mL) and air dried to give the title compound (2.35 g, 82%) as an off-white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 9.90 (s, 1H), 7.92-7.79 (m, 2H), 7.67 (d, J=8.2 Hz, 2H), 7.56 (d, J=8.0 Hz, 2H), 7.13-7.04 (m, 2H), 5.22 (s, 2H). LCMS-A rt 6.87 min, m/z (positive ion) 281 [M+H].
b) tert-Butyl 4-(2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A41)
(165) 4-((4-(Trifluoromethyl)benzyl)oxy)benzaldehyde A40 (200 mg, 0.714 mmol) and tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (200 mg, 0.684 mmol) were heated at reflux in water (4 mL) for 17 hours. The reaction was evaporated to dryness and the residue dissolved in THF (4 mL). PhI(OAc).sub.2 (220 mg, 0.684 mmol) was added and stirred for 17 hours. The reaction mixture was concentrated in vacuo and the crude material was purified by column chromatography (silica cartridge, 15%-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (156 mg, 41%) as a pale yellow powder. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.27 (d, J=1.9 Hz, 1H), 8.24 (d, J=1.9 Hz, 2H), 7.99 (d, J=1.9 Hz, 1H), 7.71 (d, J=8.1 Hz, 2H), 7.63 (d, J=8.0 Hz, 2H), 7.20 (d, J=8.9 Hz, 2H), 5.27 (s, 2H), 4.33 (s, 2H), 2.89 (m, 3H), 1.96 (d, J=12.0 Hz, 2H), 1.74 (s, 3H), 1.52 (s, 9H). LCMS-A rt 6.25 min, m/z (positive ion) 553 [M+H].sup.+.
c) 6-(Piperidin-4-yl)-2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridine (14)
(166) tert-Butyl 4-(2-(4-((4-(trifluoromethyl)benzyl)oxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A41 (146 mg, 0.269 mmol) in DCM (4 mL) was treated with TFA (500 L) and the resulting solution was stirred for 2 hours. 1 M aqueous NaOH (20 mL) and water (10 mL) were added and the mixture was extracted with EtOAc (250 mL). The combined organic layers were washed with water (25 mL), brine (25 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The crude material was dissolved in MeOH (3 mL) and loaded onto an SCX cartridge (10 g) which was washed with MeOH and the product eluted with 9:1 MeOH: aqueous NH.sub.4OH. The product containing fractions were concentrated in vacuo to give the title compound (38 mg, 31%) as a colourless solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.20 (br s, 1H), 8.15 (d, J=8.5 Hz, 2H), 7.78 (d, J=8.1 Hz, 2H), 7.76 (br s, 1H) 7.70 (d, J=8.0 Hz, 2H), 7.21 (d, J=8.4 Hz, 2H), 5.53 (s, 2H), 3.08 (d, J=12.0 Hz, 2H), 2.83-2.68 (m, 1H), 2.73-2.56 (m, 1H), 1.85-1.69 (d, J=12.1 Hz, 2H), 1.69-1.52 (m, 2H). LCMS-A rt 4.77 min, 94% purity; m/z (positive ion) 453 [M+H].sup.+, m/z (negative ion) 451 [MH].sup..
Example 15: Synthesis of tert-butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (15)
(167) ##STR00057##
a) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[3,3-bipyridine]-(2H)-carboxylate (A43)
(168) A solution of LiHMDS (1 M in toluene, 15.8 mL, 15.8 mmol) was added dropwise to a solution of 1-Boc-3-piperidone (3.00 g, 15.1 mmol) in dry THF (100 mL) at 78 C. under an atmosphere of nitrogen. The solution was then stirred at this temperature for 30 minutes, N-phenyl-bis(trifluoromethanesulfonimide) (5.92 g, 16.6 mmol) in dry THF (20 mL) was added and the reaction mixture was stirred at 78 C. for additional 15 minutes, and then at 0 C. for 2 hours. The reaction mixture was quenched with saturated aqueous NH.sub.4Cl (10 mL), volatiles were removed in vacuo, EtOAc (200 mL) and saturated aqueous NH.sub.4Cl (100 mL) were added, the layers were separated and the organic layer was washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a yellow gum. The residue was purified by silica gel chromatography (120 g silica Cartridge, 0-10% EtOAc in petroleum benzine 40-60 C.), fractions were combined and concentrated in vacuo to give the product (2.910 g, impure) as a pale yellow oil which solidified upon standing. The product was taken into next reaction without further purification.
(169) To a solution of above intermediate (2.900 g) in dry 1,4-dioxane (40 mL) was added KOAc (1.804 g, 18.38 mmol), bis(pinacolato)diboron (2.334 g, 9.191 mmol) and the suspension was de-gassed with nitrogen gas. Dppf (0.173 g, 0.306 mmol) followed by PdCl.sub.2(dppf) DCM solvate (0.253 g, 0.306 mmol) were added and the reaction was sealed and heated to 80 C. for 18 hours. The reaction was filtered through celite, which was washed with MeOH and EtOAc, the filtrates were combined and concentrated in vacuo to give a brown oil. The crude material was purified by silica gel chromatography (120 g silica Cartridge, 0-20% EtOAc in petroleum benzine 40-60 C.), fractions were combined and concentrated in vacuo to give the product (2.38 g, impure). A part of this material (0.711 g) and 5-bromo-3-nitropyridin-2-amine (0.167 g, 0.766 mmol) were dissolved in dry 1,4-dioxane (7 mL) and PdCl.sub.2(dppf) DCM solvate (0.032 g, 0.038 mmol) followed by a solution of K.sub.2CO.sub.3 (0.318 g, 2.30 mmol) in water (0.766 mL) were added. The reaction mixture was then heated at 80 C. for 18 hours. The reaction mixture was filtered through celite, washed with EtOAc (520 mL) and then concentrated in vacuo to give a brown solid. The crude material was purified by silica gel chromatography (40 g silica Cartridge, 0-40% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.095 g, 7% over 3 steps) as a yellow solid. .sup.1H NMR (400 MHz, d-DMSO) 8.56 (d, J=2.4 Hz, 1H), 8.23 (d, J=2.4 Hz, 1H), 7.96 (s, 2H), 6.38-6.30 (m, 1H), 4.17 (q, J=2.2 Hz, 2H), 3.45 (t, J=5.7 Hz, 2H), 2.28-2.19 (m, 2H), 1.43 (s, 9H). LCMS-A rt 6.48 min, m/z (positive ion) 321.2 [M+H].sup.+.
b) tert-Butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (15)
(170) To tert-butyl 6-amino-5-nitro-5,6-dihydro-[3,3-bipyridine]-1(2H)-carboxylate A43 (0.093 g, 0.29 mmol) and platinum(IV) oxide (0.010 g) under an atmosphere of nitrogen was added DIPEA (5 mL) followed by EtOH (2 mL). The reaction was stirred under an atmosphere of hydrogen (balloon) for 40 hours. The mixture was filtered through celite, and the celite was washed with EtOAc (520 mL). The combined filtrates were evaporated to give a grey solid. This material (0.103 g) and 4-(phenoxymethyl)-benzaldehyde A20 (0.060 g, 0.28 mmol) were dissolved in dry MeOH (5 mL) and activated 3 molecular sieves (0.200 g) were added. The reaction mixture was heated at reflux for 20 hours, cooled to room temperature, the solution was decanted from the sieves and the solvent was removed in vacuo. Tetahydrofuran (5 mL) followed by (diacetoxyiodo)benzene (0.208 g, 0.646 mmol) were added under an atmosphere of nitrogen and the reaction was stirred at room temperature for 3 hours. The reaction was concentrated in vacuo and diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL), the combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (24 g silica Cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.063 g, 46%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.40 (br s, 1H), 8.28 (d, J=2.0 Hz, 1H), 8.26-8.19 (m, 2H), 7.90 (s, 1H), 7.63 (d, J=8.1 Hz, 2H), 7.35-7.26 (m, 2H), 7.04 (d, J=8.0 Hz, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.20 (s, 2H), 4.06-3.92 (m, 2H), 3.04-2.72 (m, 3H), 1.95 (d, J=12.1 Hz, 1H), 1.83-1.67 (m, 2H), 1.56-1.35 (m, 10H). LCMS-A rt 6.33 min, m/z (positive ion) 485.3 [M+H].sup.+.
Example 16: Synthesis of 2-(4-(phenoxymethyl)phenyl)-6-(piperidin-3-yl)-3H-imidazo[4,5-b]pyridine (16)
(171) ##STR00058##
(172) tert-Butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate 15 (0.060 g, 0.12 mmol) was dissolved in DCM (10 mL) under an atmosphere of nitrogen and trifluoroacetic acid (0.284 mL, 3.71 mmol) was added and the resulting mixture was stirred at room temperature for 18 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (70 mL) and 2 M aqueous NaOH (70 mL), the layers were separated and the aqueous layer was extracted with EtOAc (50 mL), the combined organics were washed with water (50 mL), brine (50 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The solid was suspended in DCM (5 mL) and the solution was concentrated in vacuo to give the title compound (0.037 g, 78%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.28-8.15 (m, 3H), 7.83 (s, 1H), 7.63 (d, J=8.0 Hz, 2H), 7.31 (t, J=7.8 Hz, 2H), 7.04 (d, J=8.1 Hz, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.19 (s, 2H), 3.05-2.91 (m, 2H), 2.77 (tt, J=10.7, 3.0 Hz, 1H), 2.66-2.52 (m, 2H, obscured by DMSO signal), 1.96-1.88 (m, 1H), 1.76-1.61 (m, 2H), 1.59-1.44 (m, 1H). NH protons not observed. LCMS-A rt 4.68 min, m/z (positive ion) 385.2 [M+H].sup.+.
Example 17: Synthesis 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine (17)
(173) ##STR00059##
a) 6-Chloropyridine-2,3-diamine (A45)
(174) Iron powder (9.65 g, 173 mmol) was added to a suspension of 6-chloro-3-nitropyridin-2-amine A44 (10.0 g, 57.6 mmol) and NH.sub.4Cl (6.16 g, 115 mmol) in isopropanol (180 mL) and water (90 mL). The resulting mixture was heated at 90 C. for one hour. After this time, the suspension was left to cool to room temperature, then diluted with EtOAc (100 mL), filtered through Celite and the residues washed with further EtOAc (2150 mL). The filtrate was washed with water (3100 mL), brine (100 mL), dried over Na.sub.2SO.sub.4 and the volatiles removed under reduced pressure to give the title compound (7.50 g, 91%) as a dark brown solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 6.68 (d, J=7.8 Hz, 1H), 6.35 (d, J=7.8 Hz, 1H), 5.78 (s, 2H), 4.76 (s, 2H).
b) (4-(5-Chloro-3H-imidazo[4,5-b]pyridin-2-yl)phenyl)(phenyl)methanone (17)
(175) A suspension of 6-chloropyridine-2,3-diamine A45 (1.00 g, 6.97 mmol) and 4-(benzyloxy)benzaldehyde A8 (1.48 g, 6.97 mmol) in MeOH (25 mL) was heated under microwave irradiation at 120 C. for 15 minutes. The volatiles were removed in vacuo and the residue dissolved in THF (50 mL). PhI(OAc).sub.2 (2.24 g, 6.97 mmol) was added and the resulting mixture stirred for 18 hours at room temperature. The volatiles were removed in vacuo, the residue suspended in saturated aqueous NaHCO.sub.3 (100 mL) and filtered giving a brown solid which was washed with saturated aqueous NaHCO.sub.3 (100 mL), water (100 mL) and diethyl ether (100 mL). The resulting solid was allowed to air dry for approx 72 hours to give the title compound (1.71 g, 73%) as a brown solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) b 8.15 (d, J=8.8 Hz, 2H), 7.97 (d, J=8.3 Hz, 1H), 7.52-7.47 (m, 2H), 7.45-7.39 (m, 2H), 7.38-7.32 (m, 1H), 7.24-7.19 (m, 3H), 5.21 (s, 2H).
Example 18: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yloxy)-3H-imidazo[4,5-b]pyridine (18)
(176) ##STR00060##
a) tert-Butyl 4-((6-amino-5-nitropyridin-2-yl)oxy)piperidine-1-carboxylate (A48)
(177) tert-Butyl 4-hydroxypiperidine-1-carboxylate A47 (0.290 g, 1.44 mmol) was dissolved in dry DMF (7 mL) and NaH (60% dispersion in mineral oil, 0.086 g, 2.2 mmol) was added in one portion. After 10 minutes, 2-amino-6-chloro-3-nitropyridine A44 (0.250 g, 1.44 mmol) was added and the reaction mixture was stirred at room temperature for 18 hours. The reaction was quenched by addition of water (4 mL) and the mixture was diluted with saturated aqueous NaHCO.sub.3 (30 mL) and EtOAc (50 mL). The layers were separated and the aqueous layer was extracted with EtOAc (340 mL), the combined organics were washed with brine (50 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a yellow oily solid. The crude material was purified by silica gel chromatography (40 g silica cartridge, 0-40% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.157 g, 32%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.25 (d, J=9.1 Hz, 1H), 8.11 (s, 2H), 6.12 (d, J=9.1 Hz, 1H), 5.25-5.14 (m, 1H), 3.71-3.62 (m, 2H), 3.22-3.11 (m, 2H), 2.01-1.92 (m, 2H), 1.62-1.51 (m, 2H), 1.40 (s, 9H). LCMS-A rt 6.75 min; no product ions detected.
b) tert-Butyl 4-((5,6-diaminopyridin-2-yl)oxy)piperidine-1-carboxylate (A49)
(178) Iron powder (0.128 g, 2.29 mmol) followed by NH.sub.4Cl (0.123 g, 2.29 mmol) were added to a stirred suspension of tert-butyl 4-((6-amino-5-nitropyridin-2-yl)oxy)piperidine-1-carboxylate A48 (0.155 g, 0.458 mmol) in isopropanol (6 mL) and water (3 mL) at room temperature. The reaction was heated to 70 C. and stirred at this temperature for 2 hours, then cooled and filtered through a plug of celite which was washed with EtOAc (100 mL). The filtrate was washed with saturated aqueous NaHCO.sub.3 (50 mL), brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.130 g, 92%) as a brown glassy solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 6.72 (d, J=7.9 Hz, 1H), 5.77 (d, J=7.9 Hz, 1H), 5.29 (s, 2H), 4.88-4.78 (m, 1H), 4.09 (s, 2H), 3.66-3.57 (m, 2H), 3.18-3.06 (m, 2H), 1.89-1.78 (m, 2H), 1.52-1.35 (m, 11H). LCMS-A rt 4.90 min, m/z (positive ion) 309.2 [M+H].sup.+.
c) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)oxy)piperidine-1-carboxylate (A50)
(179) tert-Butyl 4-((5,6-diaminopyridin-2-yl)oxy)piperidine-1-carboxylate A49 (0.126 g, 0.409 mmol) and 4-(benzyloxy)benzaldehyde A8 (0.104 g, 0.490 mmol) were suspended in water (10 mL) and MeOH (2 mL) and the reaction mixture was heated at reflux for 20 hours then cooled to room temperature and the solvent was removed in vacuo. Tetrahydrofuran (10 mL) followed by (Diacetoxyiodo)benzene (0.132 g, 0.409 mmol) were added under an atmosphere of nitrogen and the mixture was stirred at room temperature for 3 hours. The reaction was concentrated in vacuo and diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL), the combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (40 g silica cartridge, 0-40% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.106 g, 52%) as a pale yellow foam. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.21 (brs, 1H), 8.10 (d, J=8.9 Hz, 2H), 7.99-7.78 (m, 1H), 7.49 (d, J=7.0 Hz, 2H), 7.46-7.38 (m, 2H), 7.38-7.32 (m, 1H), 7.17 (d, J=8.6 Hz, 2H), 6.63 (d, J=8.5 Hz, 1H), 5.20 (s, 3H), 3.75 (dt, J=9.5, 4.4 Hz, 2H), 3.19 (s, 2H), 2.08-1.96 (m, 2H), 1.66-1.53 (m, 2H), 1.42 (s, 9H). LCMS-A rt 6.23 min, m/z (positive ion) 501.3 [M+H].sup.+.
d) 2-(4-(Benzyloxy)phenyl)-5-(piperidin-4-yloxy)-3H-imidazo[4,5-b]pyridine (18)
(180) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)oxy)piperidine-1-carboxylate A50 (0.106 g, 0.212 mmol) was dissolved in DCM (7 mL) under an atmosphere of nitrogen, trifluoroacetic acid (0.486 mL, 6.35 mmol) was added and the resulting mixture was stirred at room temperature for 20 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (70 mL) and 2 M aqueous NaOH (70 mL), the layers were separated and the aqueous layer was extracted with EtOAc (50 mL), the combined organics were washed with brine (50 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The solid was dissolved in DCM (5 mL) and MeOH (2 mL) and the solution was concentrated in vacuo to give the title compound (0.075 g, 88%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.12-8.03 (m, 2H), 7.85 (d, J=7.0 Hz, 1H), 7.51-7.45 (m, 2H), 7.45-7.38 (m, 2H), 7.38-7.31 (m, 1H), 7.16 (d, J=8.7 Hz, 2H), 6.59 (d, J=8.5 Hz, 1H), 5.19 (s, 2H), 5.10-4.98 (m, 1H), 2.98 (dt, J=12.4, 3.8 Hz, 2H), 2.63-2.54 (m, 2H), 2.05-1.94 (m, 2H), 1.57-1.43 (m, 2H). LCMS-A rt 4.67 min, m/z (positive ion) 401.3 [M+H].sup.+.
Example 19: Synthesis of 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)morpholine (19)
(181) ##STR00061##
a) 6-Morpholino-3-nitropyridin-2-amine (A51)
(182) Potassium tert-butoxide (178 mg, 1.58 mmol), THF (10 mL) and morpholine (0.150 mL, 1.73 mmol) were stirred at room temperature for five minutes, then 6-chloro-3-nitropyridin-2-amine A44 (250 mg, 1.44 mmol) was added and the orange-red mixture stirred at room temperature for 18 hours. The mixture was poured into water (140 mL), the precipitate collected by filtration and air dried. Purification by column chromatography (40 g silica cartridge, 5-100% EtOAc/hexanes) gave the title compound (166 mg, 51%) as a yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.20 (d, J=9.4 Hz, 1H), 7.95 (br s, 1H), 6.05 (d, J=9.4 Hz, 1H), 5.57 (br s, 1H), 3.80-3.74 (m, 4H), 3.73-3.66 (m, 4H). LCMS-A: rt 5.38 min; m/z (positive ion) 225.2 [M+H].sup.+.
b) 4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)morpholine (19)
(183) A mixture of 6-morpholino-3-nitropyridin-2-amine A51 (165 mg, 0.74 mmol) and 2:1 MeOH:THF (9 mL) was cooled to 0 C. and NiCl.sub.2.6H.sub.2O (18 mg, 10 mol %) was added. NaBH.sub.4 (139 mg, 3.68 mmol) was added in portions (3 portions, 5 minutes apart). After all the NaBH.sub.4 was added, stirring was continued at 0 C. for ten minutes, and the mixture was quenched with saturated aqueous NH.sub.4Cl (10 mL). The volatile solvents were removed in vacuo, the residue diluted with water (20 mL) and extracted with EtOAc (330 mL). The combined EtOAc phases were washed with 5% w/v tetrasodium EDTA solution (50 mL), brine (50 mL) dried over Na.sub.2SO.sub.4, filtered and evaporated to give a dark solid residue (97 mg). The dark solid residue, 4-(benzyloxy)benzaldehyde A8 (106 mg, 0.50 mmol) and EtOH (20 mL) were heated at reflux under air. After 18 hours the mixture was concentrated and the residue purified by chromatography (12 g silica cartridge, 0-100% EtOAc/hexanes to give the title compound (31 mg, 16%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 12.89 (br s, 1H), 8.09-8.04 (m, 2H), 7.78 (d, J=8.7 Hz, 1H), 7.50-7.45 (m, 2H), 7.44-7.38 (m, 2H), 7.37-7.32 (m, 1H), 7.14 (d, J=8.9 Hz, 2H), 6.76 (d, J=8.9 Hz, 1H), 5.18 (s, 2H), 3.78-3.71 (m, 4H), 3.47-3.43 (m, 4H). LCMS-A: 4.96 min; m/z (positive ion) 387.2 [M+H]; 385.2 [MH].sup..
Example 20: Synthesis of 2-(4-(benzyloxy)phenyl)-N-(1H-pyrazol-4-yl)-3H-imidazo[4,5-b]pyridin-5-amine (20)
(184) ##STR00062##
a) 2-(4-(Benzyloxy)phenyl)-5-chloro-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridine (A52)
(185) NaH (60% dispersion in oil, 71 mg, 1.8 mmol) was added to a stirred solution of 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine 17 (500 mg, 1.49 mmol) in THF (6 mL) and DMF (3 mL) at room temperature under nitrogen. The resulting brown solution was stirred for 30 minutes, SEM-Cl (395 L, 2.23 mmol) was added dropwise and the solution was stirred for 1 hour. Water (20 mL) and EtOAc (50 mL) were added and the layers were separated. The aqueous layer was extracted with DCM (50 mL). The combined organic layers were washed with water (25 mL): saturated brine (25 mL), dried over MgSO.sub.4, filtered and concentrated in vacuo. The crude material was purified by column chromatography (40 g silica cartridge, 5%-50% EtOAc in petroleum benzine 40-60 C.) to give the title compound (330 mg, 47%) as a pale yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.08 (d, J=8.8 Hz, 2H), 7.98 (d, J=8.3 Hz, 1H), 7.49-7.44 (m, 2H), 7.44-7.38 (m, 2H), 7.38-7.34 (m, 1H), 7.26 (d, J=8.3 Hz, 1H), 7.13 (d, J=8.8 Hz, 2H), 5.64 (s, 2H), 5.16 (s, 2H), 3.97-3.79 (m, 2H), 1.16-0.87 (m, 2H), 0.00 (s, 9H).
b) tert-Butyl 4-nitro-1H-pyrazole-1-carboxylate (A54)
(186) DMAP (0.540 g, 4.42 mmol) was added to a suspension of 4-nitro-1H-pyrazole A53 (2.50 g, 22.1 mmol) and Boc anhydride (4.83 g, 22.1 mmol) in DCM (150 mL). The resulting reaction mixture slowly went into solution and was allowed to stir for 20 hours at room temperature. The reaction mixture was washed with water (100 mL), brine (100 mL), dried (phase separation cartridge) and concentrated under reduced pressure to give a pale yellow foam. This residue was purified by silica gel chromatography (240 g silica cartridges eluting with 0-75% EtOAc in petroleum benzine 40-60 C.) to give the title compound (3.72 g, 79%) as a white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.78 (d, J=0.6 Hz, 1H), 8.22 (d, J=0.4 Hz, 1H), 1.68 (s, 9H). LCMS-A rt 5.30 min; no product ions detected.
c) tert-Butyl 4-amino-1H-pyrazole-1-carboxylate (A55)
(187) A suspension of tert-butyl 4-nitro-1H-pyrazole-1-carboxylate A54 (3.70 g, 17.4 mmol) and 10% Pd/C wetted with ca. 53% water (0.300 g) in EtOH (150 mL) were stirred under hydrogen (1 atm) at room temperature for 20 hours. The reaction mixture was then filtered through celite, the plug was washed with EtOAc (ca. 100 mL) and the filtrate concentrated under reduced pressure to give the title compound (3.09 g, 97%) as a pale brown solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.54 (d, J=0.6 Hz, 1H), 7.40 (d, J=0.8 Hz, 1H), 3.10 (s, 2H), 1.62 (s, 9H). LCMS-A rt 3.75 min; no product ions detected.
d) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)-1H-pyrazole-1-carboxylate (A56)
(188) A flask containing a suspension of 2-(4-(benzyloxy)phenyl)-5-chloro-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridine A52 (51.3 mg, 133 mol), tert-butyl 4-amino-1H-pyrazole-1-carboxylate A55 (24.5 mg, 133 mol), chloro[2-(dicyclohexylphosphino)-3,6-dimethoxy-2,4,6-triisopropyl-1,1-biphenyl][2-(2-aminoethyl)phenyl]palladium(II) (10.4 mg, 13 mol) and K.sub.2CO.sub.3 (36.5 mg, 264 mol) in t-BuOH (1 mL) was evacuated and purged with nitrogen three times. The suspension was heated at 85 C. for 3 hours and then cooled to room temperature. EtOAc (10 mL) and water (5 mL) were added and the layers separated. The aqueous layer was extracted with EtOAc (5 mL), the combined organic layers were dried with Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by column chromatography (12 g silica cartridge, 10-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (48.5 mg, 71%) as a pale yellow oil. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.73 (d, J=0.9 Hz, 1H), 8.06 (d, J=8.8 Hz, 2H), 7.86 (d, J=8.5 Hz, 1H), 7.80 (d, J=0.9 Hz, 1H), 7.46 (m, 2H), 7.44-7.37 (ddd, J=8.0, 6.9, 1.0 Hz, 2H), 7.35 (d, J=7.2 Hz, 1H), 7.11 (d, J=8.8 Hz, 2H), 6.83 (s, 1H), 6.61 (d, J=8.6 Hz, 1H), 5.64 (s, 2H), 5.14 (s, 2H), 4.01-3.83 (m, 2H), 1.68 (s, 9H), 1.19-0.92 (m, 2H), 0.09 (s, 9H). LCMS-B rt 4.01 min; no product ions detected.
e) 4-((2-(4-(Benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)-1H-pyrazole (20)
(189) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)-1H-pyrazole-1-carboxylate A56 (48.5 mg, 79.1 mol) was dissolved in CDCl.sub.3 (2 mL) and TFA (1 mL) and was stirred for 18 hours at room temperature. The reaction mixture was concentrated in vacuo and purified by column chromatography (12 g silica cartridge, 2-10% (10% Et.sub.3N in MeOH) in EtOAc) to give the title compound (10.5 mg, 34%) as a pale yellow solid. .sup.1H NMR (400 MHz, CD.sub.3OD) 8.07-7.80 (m, 4H), 7.69 (d, J=8.7 Hz, 1H), 7.46 (d, J=7.0 Hz, 2H), 7.39 (t, J=7.5 Hz, 2H), 7.33 (d, J=5.9 Hz, 1H), 7.13 (d, J=8.9 Hz, 2H), 6.61 (d, J=8.7 Hz, 1H), 5.17 (s, 2H); LCMS-B rt 2.99 min, m/z (positive ion) 383 [M+H].sup.+, m/z (negative ion) 381 [MH].sup..
Example 21: Synthesis of 1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (21)
(190) ##STR00063##
a) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3-oxopiperazine-1-carboxylate (A57)
(191) A suspension of 2-(4-(benzyloxy)phenyl)-5-chloro-3-((2-(tri methylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridine A52 (50 mg, 0.11 mmol), N-Boc-3-oxopiperazine (43 mg, 0.22 mmol), Ruphos (2.5 mg, 0.0054 mmol), chloro-(2-dicyclohexylphosphino-2,6-diisopropoxy-1, 1-biphenyl)[2-(2-aminoethyl)phenyl]palladium(II)-methyl-t-butyl ether adduct (4.4 mg, 0.0054 mmol) and Cs.sub.2CO.sub.3 (42 mg, 0.13 mmol) in t-BuOH (1 mL) was evacuated and purged with nitrogen three times. The suspension was heated at 85 C. for 3 hours. The reaction was cooled to room temperature and left overnight. The reaction mixture was filtered and the residue purified by column chromatography twice (4 g silica cartridge, then 12 g silica cartridge, 12-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (5.0 mg, 7%) as a pale colourless oil. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.14-8.01 (m, 3H), 7.84 (d, J=8.5 Hz, 1H), 7.49-7.44 (m, 2H), 7.44-7.38 (m, 2H), 7.38-7.32 (m, 1H), 7.13 (d, J=8.8 Hz, 2H), 5.61 (s, 2H), 5.16 (s, 2H), 4.32 (s, 2H), 4.23-4.04 (m, 2H), 3.96-3.65 (m, 4H), 1.51 (s, 9H), 1.02 (dd, J=8.8, 7.7 Hz, 2H), 0.01 (s, 9H); LCMS-A rt 7.65 min; m/z (positive ion) 630 [M+H].sup.+.
b) 1-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (21)
(192) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3-oxopiperazine-1-carboxylate A57 (5.0 mg, 7.9 mol) was dissolved in DCM (400 L) and TFA (200 L) for 18 hours at room temperature. The reaction mixture was treated with 2% NaOH (3 mL) and the volatiles removed in vacuo. The aqueous layer was extracted with EtOAc (35 mL). The combined organic layers were washed with brine (3 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to give the title compound (2.0 mg, 63%) as a colourless solid. .sup.1H NMR (400 MHz, CD.sub.3OD) 8.07 (d, J=8.9 Hz, 2H), 8.00-7.90 (m, 1H), 7.54 (d, J=8.4 Hz, 1H), 7.51-7.44 (m, 2H), 7.44-7.36 (m, 2H), 7.36-7.29 (m, 1H), 7.18 (d, J=8.9 Hz, 2H), 5.20 (s, 2H), 4.00 (t, J=5.5 Hz, 2H), 3.63 (s, 2H), 3.23 (t, J=5.5 Hz, 2H). LCMS-B rt 2.94 min; m/z (positive ion) 400 [M+H].sup.+; m/z (negative ion) 398 [MH].sup..
(193) General Method A:
(194) A solution of 2-amino-6-chloro-3-nitropyridine A44 (1 equiv), amine (1.2 equiv) and diisopropylethylamine (2 equiv) in DMF (10 mL/g) was heated at 80 C. for 45 minutes or until the reaction had gone to completion as judged by TLC or LCMS. The reaction was cooled to room temperature and treated with water (20 mL/g). The product was collected by vacuum filtration and washed with water until the liquors ran clear. The product was dried under vacuum.
(195) General Method B:
(196) 1 M Na.sub.2S.sub.2O.sub.4 solution (3 equiv.) was added to a suspension of 4-(benzyloxy)benzaldehyde A8 (1.1 equiv) and the 2-amino-3-nitropyridine (1 equiv) in EtOH (40 mL/g). The resulting yellow suspension was heated to 70 C. or 110 C. for 15 minutes in a microwave. The reaction was cooled to room temperature, 5 M aqueous NH.sub.4OH (10 mL/g) was added and the reaction mixture was stirred for 5 minutes at room temperature. The suspension was filtered to give the desired product or partitioned between water (50 mL) and EtOAc (50 mL). The aqueous layer was extracted with EtOAc (50 mL). The combined organic layers were washed with water (30 mL), saturated brine (30 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude product was further purified by column chromatography (silica cartridge) if necessary.
Example 22: Synthesis of N-(2-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)ethyl)acetamide (22)
(197) ##STR00064##
a) N-(2-((6-Amino-5-nitropyridin-2-yl)amino)ethyl)acetamide (A59)
(198) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (500 mg, 2.88 mmol), N-(2-aminoethyl)acetamide (346 mg, 3.46 mmol). The title compound (530 mg, 77%) was isolated as a yellow solid. LCMS-B rt 2.69 min, m/z (positive ion) 240 [M+H].sup.+.
b) N-(2-((2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)ethyl)acetamide (22)
(199) General Method B: N-(2-((6-amino-5-nitropyridin-2-yl)amino)ethyl)acetamide A59 (100 mg, 0.418 mmol). Isolated the title compound (12.0 mg, 7%) as a colourless powder. .sup.1H NMR (400 MHz, CD.sub.3OD) 7.95 (d, J=8.3 Hz, 2H), 7.61 (d, J=8.6 Hz, 1H), 7.52-7.43 (m, 2H), 7.43-7.35 (m, 2H), 7.35-7.28 (m, 1H), 7.13 (d, J=8.9 Hz, 2H), 6.45 (d, J=8.7 Hz, 1H), 5.17 (s, 2H), 3.53 (t, J=5.9 Hz, 2H), 3.3.43 (t, J=6.0 Hz, 2H), 1.94 (s, 3H); LCMS-B rt 2.97 min; m/z (positive ion) 402; m/z (negative ion) 400.
Example 23: Synthesis of 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine (23)
(200) ##STR00065##
a) 3-Nitro-6-thiomorpholinopyridin-2-amine (A61)
(201) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (500 mg, 2.88 mmol), thiomorpholine A60 (356 mg, 3.46 mmol). Isolated the title compound (615 mg, 88%) as a yellow powder. LCMS-B rt 3.24 min, m/z (positive ion) 241 [M+H].sup.+.
b) 4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine (23)
(202) General Method B: 3-nitro-6-thiomorpholinopyridin-2-amine A61 (200 mg, 0.832 mmol). Isolated the title compound (145 mg, 44%) as a colourless powder. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.06 (d, J=8.9 Hz, 2H), 7.89-7.67 (br, d, J=8.8 Hz, 1H), 7.52-7.45 (m, 2H), 7.41 (t, J=7.3 Hz, 2H), 7.37-7.29 (m, 1H), 7.19-7.08 (d, J=8.3 Hz, 3H), 6.75 (d, J=8.8 Hz, 1H), 5.18 (s, 2H), 4.04-3.79 (m, 4H), 2.72-2.57 (m, 4H). LCMS-B rt 3.18 min; m/z (positive ion) 403 [M+H].sup.+; m/z (negative ion) 401 [MH].sup..
Example 24: Synthesis of 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 1-oxide (24)
(203) ##STR00066##
(204) 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 23 (44.2 mg, 0.110 mmol) was dissolved in DCM (5 mL) and mCPBA (25 mg, 0.10 mmol) was added at room temperature. The solution was stirred for 10 minutes, Ca(OH).sub.2 (13 mg, 0.18 mmol) was added to give a light, cloudy suspension. The suspension was stirred for 1 hour. The mixture was filtered and the residue washed with DCM (310 mL) and the filtrate concentrated in vacuo. The crude material was purified by column chromatography (4 g silica cartridge, 80-100% EtOAc:petroleum benzine 40-60 C. then 0-20% MeOH:EtOAc) to give a 2:1 mixture of products. Water (10 mL) was added to the NMR sample (in d.sub.6-DMSO) which was extracted with DCM (210 mL) to remove the minor impurity. The product was extracted from the cloudy aqueous layer using EtOAc (220 mL). The combined EtOAc organic layers were washed with water (20 mL), brine (20 mL), dried over MgSO.sub.4 and concentrated to give the title compound (1.4 mg, 3%) as a pale yellow solid. .sup.1H NMR (400 MHz, CD.sub.3OD) 7.98 (d, J=8.8 Hz, 2H), 7.79 (d, J=8.8 Hz, 1H), 7.51-7.44 (m, 2H), 7.42-7.35 (m, 2H), 7.35-7.30 (m, 1H), 7.14 (d, J=8.9 Hz, 2H), 6.91 (d, J=8.9 Hz, 1H), 5.18 (s, 2H), 4.44-3.93 (m, 4H), 3.19-2.94 (ddd, J=13.7, 9.4, 4.2 Hz, 2H), 2.91-2.70 (dt, J=14.2, 2.7 Hz, 2H); LCMS-B rt 2.97 min; m/z (positive ion) 419 [M+H].sup.+; m/z (negative ion) 417 [MH].sup..
Example 25: Synthesis of 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 1,1-dioxide (25)
(205) ##STR00067##
(206) 4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)thiomorpholine 23 (50 mg, 0.12 mmol) was dissolved in DCM (5 mL). mCPBA (67 mg, 0.27 mmol) was added at 0 C. and warmed to room temperature. The solution was stirred for 5 minutes, Ca(OH).sub.2 (20 mg, 0.27 mmol) was added to give a light, cloudy suspension. The mixture was filtered and the residue washed with DCM (310 mL). The combined filtrates were washed with 2 M aqueous Na.sub.2CO.sub.3 (220 mL), brine (20 mL) and concentrated in vacuo to give a cream coloured solid. The crude material was purified by column chromatography (12 g silica cartridge, 50%-100% EtOAc: petroleum benzine 40-60 C.) to give the title compound as a colourless solid (2.3 mg, 4%); .sup.1H NMR (400 MHz, CD.sub.3OD) (8.00 (d, J=8.9 Hz, 2H), 7.83 (d, J=8.7 Hz, 1H), 7.55-7.45 (m, 2H), 7.44-7.37 (ddd, J=7.9, 7.0, 1.0 Hz, 2H), 7.37-7.30 (d, J=7.2 Hz, 1H), 7.16 (d, J=8.9 Hz, 2H), 6.95 (d, J=8.8 Hz, 1H), 5.19 (s, 2H), 4.23 (d, J=5.0 Hz, 4H), 3.16 (m, 4H); LCMS-B rt 3.05 min; m/z (positive ion) 435 [M+H].sup.+.
Example 26: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(4-methylpiperazin-1-yl)-3H-imidazo[4,5-b]pyridine (26)
(207) ##STR00068##
a) 6-(4-Methylpiperazin-1-yl)-3-nitropyridin-2-amine (A63)
(208) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (200 mg, 1.15 mmol), N-methylpiperidine (179 mg, 0.754 mmol). Isolated the title compound (179 mg, 65%) as a yellow solid. LCMS-B rt 2.09 min, m/z (positive ion) 238 [M+H].sup.+.
b) 2-(4-(Benzyloxy)phenyl)-5-(4-methylpiperazin-1-yl)-3H-imidazo[4,5-b]pyridine (26)
(209) General Method B: 6-(4-methylpiperazin-1-yl)-3-nitropyridin-2-amine A63 (95.0 mg, 0.400 mmol). The reaction was filtered, the residue dissolved in MeOH and loaded onto a SCX cartridge. The SCX cartridge was washed with MeOH (310 mL), the product was eluted with 10% NH.sub.4OH in MeOH (50 mL) and concentrated to give the title compound (17.5 mg, 11%) as a colourless solid. .sup.1H NMR (400 MHz, CD.sub.3OD) 7.97 (d, J=8.8 Hz, 2H), 7.74 (d, J=8.8 Hz, 1H), 7.50-7.43 (m, 2H), 7.38 (t, J=7.4 Hz, 2H), 7.35-7.28 (m, 1H), 7.12 (d, J=8.8 Hz, 2H), 6.78 (d, J=8.8 Hz, 1H), 5.16 (s, 2H), 3.60 (d, J=4.9 Hz, 4H), 2.61 (t, J=5.1 Hz, 4H), 2.36 (s, 3H); LCMS-B rt 2.86 min, m/z (positive ion) 400 [M+H].sup.+; m/z (negative ion) 398 [MH].sup..
Example 27: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (27)
(210) ##STR00069##
a) 6-(4-(Ethylsulfonyl)piperazin-1-yl)-3-nitropyridin-2-amine (A65)
(211) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (200 mg, 1.15 mmol), 1-(ethylsulfonyl)piperazine A64 (179 mg, 0.754 mmol). Isolated the title compound (110 mg, 30%) as a yellow solid. LCMS-B rt 3.09 min, m/z (positive ion) 316 [M+H].sup.+.
b) 2-(4-(Benzyloxy)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (27)
(212) General Method B: 6-(4-(ethylsulfonyl)piperazin-1-yl)-3-nitropyridin-2-amine A65 (126.1 mg, 0.400 mmol). The reaction was filtered, the residue dissolved in MeOH and loaded onto a SCX cartridge. The SCX was washed with MeOH (310 mL), the product was eluted with 10% NH4OH in MeOH (50 mL) and concentrated to give the title compound (100 mg, 52%) as a colourless solid. 1H NMR (400 MHz, d6-DMSO) 8.21-7.96 (d, J=8.9 Hz, 2H), 7.92-7.75 (d, J=8.8 Hz, 1H), 7.52-7.44 (d, J=6.8 Hz, 2H), 7.45-7.37 (m, 2H), 7.37-7.31 (m, 1H), 7.17-7.10 (d, J=8.6 Hz, 2H), 6.86-6.77 (d, J=8.8 Hz, 1H), 5.42-4.96 (s, 2H), 3.69-3.55 (s, 4H), 3.34-3.22 (d, J=4.9 Hz, 4H), 3.15-2.96 (q, J=7.3 Hz, 2H), 1.41-1.01 (t, J=7.3 Hz, 3H); LCMS-B rt 3.17 min, m/z (positive ion) 478 [M+H].sup.+; m/z (negative ion) 476 [MH].sup..
Example 28: Synthesis of tert-butyl ((1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-3-yl)methyl)carbamate (28)
(213) ##STR00070##
a) tert-Butyl ((1-(6-amino-5-nitropyridin-2-yl)piperidin-3-yl)methyl)carbamate (A67)
(214) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (174 mg, 1.00 mmol), tert-butyl (piperidin-3-ylmethyl)carbamate (258 mg, 1.20 mmol). The reaction was cooled to room temperature, treated with water (20 mL/g) and filtered. The filtrate was extracted with EtOAc (25 mL), the combined organics were washed with brine (5 mL) and concentrated to give the title compound (305 mg, 87%) as a yellow powder. LCMS-B rt 3.41 min, m/z (positive ion) 352 [M+H].sup.+; m/z (negative ion) 350 [MH].sup..
b) tert-Butyl ((1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-3-yl)methyl)carbamate (28)
(215) General Method B: A67 (175 mg, 0.500 mmol). Isolated the title compound (80.4 mg, 32%) as a colourless powder. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.90 (d, J=8.3 Hz, 2H), 7.74 (br, s, 1H), 7.43 (m, 2H), 7.39 (d, J=7.8 Hz, 2H), 7.35 (d, J=6.9 Hz, 1H), 7.06 (d, J=8.8 Hz, 2H), 6.33 (d, J=8.6 Hz, 1H), 5.11 (s, 2H), 4.62 (br, s, 1H), 3.93 (br, s, 1H), 3.76 (d, J=13.1 Hz, 1H), 3.41-3.16 (m, 2H), 3.08-2.87 (m, 1H), 2.87-2.67 (m, 1H), 1.93-1.73 (m, 4H), 1.73-1.56 (m, 2H), 1.44 (s, 9H); LCMS-B rt 3.36 min, m/z (positive ion) 514 [M+H].sup.+, m/z (negative ion) 512 [MH].sup..
Example 29: Synthesis of tert-butyl 2-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (29)
(216) ##STR00071##
a) tert-Butyl 2-(((6-amino-5-nitropyridin-2-yl)amino)methyl)piperidine-1-carboxylate (A69)
(217) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (174 mg, 1.00 mmol), tert-butyl 2-(aminomethyl)piperidine-1-carboxylate A68 (258 mg, 1.20 mmol). Isolated the title compound as a yellow powder (258 mg, 73%) LCMS-B rt 3.39 min, m/z (positive ion) 352 [M+H].sup.+; m/z (negative ion) 350 [MH].sup..
b) tert-Butyl 2-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (29)
(218) General Method B: tert-butyl 2-(((6-amino-5-nitropyridin-2-yl)amino)methyl)piperidine-1-carboxylate A69 (66 mg, 0.31 mmol). Isolated the title compound as a colourless powder (56 mg, 42%); .sup.1H NMR (400 MHz, CDCl.sub.3) 7.93 (d, J=8.2 Hz, 2H), 7.75 (br, s, 1H), 7.48-7.42 (m, 2H), 7.42-7.37 (m, 2H), 7.37-7.30 (m, 1H), 7.06 (d, J=8.8 Hz, 2H), 6.32 (d, J=8.7 Hz, 1H), 5.34-5.16 (br, s, 1H), 5.12 (s, 2H), 4.70-4.42 (m, 1H), 4.07-3.88 (br, s, 1H), 3.85-3.65 (br, s, 1H), 3.40-3.20 (br s, 1H), 2.78 (t, J=12.9 Hz, 1H), 1.95-1.75 (br, s, 2H), 1.71-1.61 (m, 2H), 1.61-1.52 (m, 2H), 1.50-1.39 (m, 1H), 1.37 (s, 9H); LCMS-B rt 3.36 min, m/z (positive ion) 514 [M+H].sup.+, m/z (negative ion) 512 [MH].sup..
Example 30: Synthesis of tert-butyl 3-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)(methyl)amino)piperidine-1-carboxylate (30)
(219) ##STR00072##
a) tert-Butyl 3-((6-amino-5-nitropyridin-2-yl)(methyl)amino)piperidine-1-carboxylate (A71)
(220) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (174 mg, 1.00 mmol), tert-butyl 3-(methylamino)piperidine-1-carboxylate A70 (258 mg, 1.20 mmol). The reaction was cooled to room temperature, treated with water (20 mL/g) and filtered. The filtrate was extracted with EtOAc (25 mL), the combined organics were washed with brine (5 mL) and concentrated to give the title compound as a yellow powder (317 mg, 90%). LCMS-B rt 3.50 min m/z (positive ion) 352 [M+H].sup.+, m/z (negative ion) 350 [MH].sup..
b) tert-Butyl 3-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)(methyl)amino)piperidine-1-carboxylate (30)
(221) General Method B: tert-butyl 3-((6-amino-5-nitropyridin-2-yl)(methyl)amino)piperidine-1-carboxylate A71 (148 mg, 0.420 mmol). Isolated the title compound as a colourless powder (90 mg, 42%); .sup.1H NMR (400 MHz, CDCl.sub.3) 7.90 (d, J=8.3 Hz, 2H), 7.81 (br, s, 1H), 7.48-7.42 (m, 2H), 7.42-7.37 (m, 2H), 7.37-7.30 (m, 1H), 7.05 (d, J=8.8 Hz, 2H), 6.54 (d, J=8.9 Hz, 1H), 5.12 (s, 2H), 4.50-4.18 (br, s, 1H), 4.50-4.18 (br, s, 1H, hidden under solvent peak), 3.06-2.88 (s, 3H), 2.87-2.69 (br, s, 1H), 2.69-2.54 (t, J=12.5 Hz, 1H), 1.97-1.55 (m, 6H), 1.47 (s, 9H); LCMS-B rt 3.45 min, m/z (positive ion) 514 [M+H].sup.+, m/z (negative ion) 512 [MH].sup..
Example 31: Synthesis of tert-butyl 4-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (31)
(222) ##STR00073##
a) tert-Butyl 4-(((6-amino-5-nitropyridin-2-yl)amino)methyl)piperidine-1-carboxylate (A73)
(223) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (174 mg, 1.00 mmol), tert-butyl 4-(aminomethyl)piperidine-1-carboxylate A72 (258 mg, 1.20 mmol). The reaction was cooled to room temperature, treated with water (20 mL/g) and filtered. The filtrate was extracted with EtOAc (25 mL), washed with brine (5 mL) and concentrated to give the title compound as a yellow powder (286 mg, 81%). LCMS-B rt 3.37 min m/z (positive ion) 352 [M+H].sup.+, m/z (negative ion) 350 [MH].sup..
b) tert-Butyl 4-(((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)methyl)piperidine-1-carboxylate (31)
(224) General Method B: tert-butyl 4-(((6-amino-5-nitropyridin-2-yl)amino)methyl)piperidine-1-carboxylate A73 (123 mg, 0.350 mmol). Isolated the title compound as a colourless powder (50 mg, 28%); .sup.1H NMR (400 MHz, CDCl.sub.3) 10.82-10.40 (br, s, 1H), 7.97-7.83 (m, 2H), 7.78 (br, s, 1H), 7.47-7.42 (m, 2H), 7.42-7.36 (m, 2H), 7.36-7.30 (m, 1H), 7.14-6.93 (m, 2H), 6.34 (d, J=8.7 Hz, 1H), 5.10 (s, 2H), 452 (t, J=6.0 Hz, 1H), 4.23-3.87 (1H hidden under solvent peak), 3.21 (t, J=6.1 Hz, 2H), 2.80-2.51 (m, 2H), 1.92-1.59 (m, 4H), 1.55-1.36 (s, 9H), 1.19-1.03 (m 2H); LCMS-B rt 3.30 min, m/z (positive ion) 514 [M+H].sup.+, m/z (negative ion) 512 [MH].sup..
Example 32: Synthesis of tert-butyl 4-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)piperidine-1-carboxylate (32)
(225) ##STR00074##
a) tert-Butyl 4-((6-amino-5-nitropyridin-2-yl)amino)piperidine-1-carboxylate (A75)
(226) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (174 mg, 1.00 mmol), tert-butyl 4-aminopiperidine-1-carboxylate (240 mg, 1.20 mmol). Isolated the title compound as a yellow powder (253 mg, 75%). LCMS-B rt 3.34 min, m/z (positive ion) 360 [M+Na].sup.+, m/z (negative ion) 336 [MH].sup..
b) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)amino)piperidine-1-carboxylate (32)
(227) General Method B: tert-Butyl 4-((6-amino-5-nitropyridin-2-yl)amino)piperidine-1-carboxylate A75 (87.7 mg, 0.260 mmol). Isolated the title compound as a colourless powder (65 mg, 50%); .sup.1H NMR (400 MHz, CDCl.sub.3) (10.67-10.25 (br, s, 1H), 7.91 (d, J=8.2 Hz, 2H), 7.84-7.66 (br, s, 1H), 7.46-7.42 (m, 2H), 7.42-7.37 (m, 2H), 7.37-7.30 (m, 1H), 7.04 (d, J=8.8 Hz, 2H), 6.33 (d, J=8.6 Hz, 1H), 5.11 (s, 2H), 4.30 (d, J=8.1 Hz, 1H), 4.14-3.93 (br, s, 2H), 3.93-3.74 (br, s, 1H), 3.05-2.67 (t, J=12.0 Hz, 2H), 2.14-1.93 (m, 2H), 1.49 (s, 9H), 1.91-1.64 (br s, 1H) 1.42-1.18 (m, 2H); LCMS-B rt 3.28 min, m/z (positive ion) 500 [M+H].sup.+, m/z (negative ion) 498 [MH].sup..
Example 33: Synthesis of 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (33)
(228) ##STR00075##
a) 4-(6-Amino-5-nitropyridin-2-yl)piperazin-2-one (A77)
(229) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (500 mg, 2.88 mmol), piperazine-2-one A76 (346 mg, 3.46 mmol). Isolated the title compound as a yellow solid (567 mg, 83%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.20 (s, 1H), 8.10 (d, J=9.5 Hz, 1H), 8.03-7.65 (s, 2H), 6.30 (d, J=9.5 Hz, 1H), 4.21 (s, 2H), 3.84 (s, 2H), 3.31-3.26 (m, 2H); LCMS-B rt 2.78 min, m/z (positive ion) 260 [M+Na].sup.+; 238 [M+H].sup.+.
b) 4-(5,6-Diaminopyridin-2-yl)piperazin-2-one (A78)
(230) A suspension of 4-(6-amino-5-nitropyridin-2-yl)piperazin-2-one A77 (550 mg, 2.32 mmol) and 10% Pd on C (53% water wet, 112 mg, 5.6 mg Pd) in MeOH (30 mL) was stirred under hydrogen (1 atm) for 17 hours. The suspension was filtered through celite and concentrated in vacuo give the title compound as a brown solid (379 mg, 79%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.89 (s, 1H), 6.69 (d, J=8.0 Hz, 1H), 5.81 (d, J=8.0 Hz, 1H), 5.21 (s, 2H), 4.01 (s, 2H), 3.68 (s, 2H), 3.56-3.40 (m, 2H), 3.26-3.18 (m, 2H).
c) 4-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazin-2-one (33)
(231) A suspension of 4-(5,6-diaminopyridin-2-yl)piperazin-2-one A78 (200 mg, 0.965 mmol) and 4-(benzyloxy)benzaldehyde A8 (205 mg, 0.965 mmol) in MeOH (5 mL) was heated under microwave irradiation at 120 C. for 20 minutes. The volatiles were removed in vacuo and the residue dissolved in THF (30 mL). PhI(OAc).sub.2 (311 mg, 0.965 mmol) was added and the resulting mixture stirred for 18 hours at room temperature. The reaction mixture was diluted with DCM (50 mL), washed with 0.5 M aqueous citric acid (30 mL); saturated aqueous Na.sub.2CO.sub.3 (30 mL) and filtered to give the crude compound (175 mg) as a green powder. The residue was dissolved in MeOH (1 mL) and purified by column chromatography (40 g silica, EtOAc:petroleum benzine) to give the title compound as a colourless solid (40.4 mg, 10%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.11-8.00 (m, 3H), 7.81 (s, 1H), 7.51-7.45 (m, 2H), 7.45-7.38 (m, 2H), 7.37-7.31 (m, 1H), 7.20-7.06 (m, 2H), 6.75 (d, J=8.9 Hz, 1H), 5.19 (s, 2H), 4.03 (s, 2H), 3.83-3.62 (m 2H), 3.48-3.31 (m, 2H)hidden under solvent peak; LCMS-B rt 2.98 min; m/z (positive ion) 400 [M+H].sup.+; m/z (negative ion) 398 [MH].sup..
Example 34: Synthesis of tert-butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (34)
(232) ##STR00076##
a) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[2,3-bipyridine]-1(2H)-carboxylate (A80)
(233) A solution of LiHMDS (1 M in toluene, 15.8 mL, 15.8 mmol) was added dropwise to a solution of 1-Boc-3-piperidone A79 (3.00 g, 15.1 mmol) in dry THF (100 mL) at 78 C. under an atmosphere of nitrogen. The solution was then stirred at this temperature for 30 minutes, N-phenyl-bis(trifluoromethanesulfonimide) (5.92 g, 16.6 mmol) in dry THF (20 mL) was added and the reaction mixture was stirred at 78 C. for additional 15 minutes, and then at 0 C. for 2 hours. The reaction mixture was quenched with saturated aqueous NH.sub.4Cl (10 mL), volatiles were removed in vacuo, EtOAc (200 mL) and saturated aqueous NH.sub.4Cl (100 mL) were added, the layers were separated and the organic layer was washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a yellow gum. The residue was purified by silica gel chromatography (120 g silica Cartridge, 0-10% EtOAc in petroleum benzine 40-60 C.), fractions were combined and concentrated in vacuo to give the product (2.910 g, impure) as a pale yellow oil which solidified upon standing. The product was taken into next reaction without further purification.
(234) To a solution of above intermediate (2.900 g) in dry 1,4-dioxane (40 mL) was added KOAc (1.804 g, 18.38 mmol), bis(pinacolato)diboron (2.334 g, 9.191 mmol) and the suspension was de-gassed with nitrogen. Dppf (0.173 g, 0.306 mmol) followed by PdCl.sub.2(dppf) DCM solvate (0.253 g, 0.306 mmol) were added and the reaction vessel was sealed and heated to 80 C. for 18 hours. The reaction mixture was filtered through celite, which was washed with MeOH and EtOAc, the filtrates were combined and concentrated in vacuo to give a brown oil. The crude material was purified by silica gel chromatography (120 g silica cartridge, 0-20% EtOAc in petroleum benzine 40-60 C.), fractions were combined and concentrated in vacuo to give the product (2.38 g, impure). A part of this material (1.670 g) and 2-amino-6-chloro-3-nitropyridine A44 (0.250 g, 1.44 mmol) were dissolved in dry 1,4-dioxane (10 mL); tetrabutylammonium bromide (0.046 g, 0.144 mmol) and Pd(PPh.sub.3).sub.2C.sub.1-2 (0.051 g, 0.072 mmol) followed by a solution of Na.sub.2CO.sub.3 (0.458 g, 4.32 mmol) in water (1.440 mL) were added. The reaction mixture was then heated at 80 C. for 18 hours. The reaction mixture was filtered through celite, which was washed with EtOAc (520 mL) and the combined organics were concentrated in vacuo to give a brown solid which was purified by silica gel chromatography (40 g silica Cartridge, 0-40% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.225 g, 7% over 3 steps) as a yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) b 8.36 (d, J=8.7 Hz, 1H), 6.92-6.82 (m, 2H), 4.36 (s, 2H), 3.56 (t, J=5.7 Hz, 2H), 2.43-2.34 (m, 2H), 1.47 (s, 9H). LCMS-A rt 6.64 min.
b) tert-Butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (34)
(235) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[2,3-bipyridine]-1(2H)-carboxylate A80 (0.221 g, 0.690 mmol) was suspended in DIPEA (6.5 mL) under an atmosphere of nitrogen and platinum(IV) oxide (0.050 g) was added suspended in EtOAc (2 mL). EtOH (2 mL) was added and the reaction was then stirred under an atmosphere of hydrogen (balloon) for 18 hours. The mixture was filtered through celite, and the celite was washed with EtOAc (520 mL). The combined filtrates were concentrated in vacuo, toluene was added to the resulting gum and then concentrated in vacuo to give to give a brown solid. This material (0.236 g) and 4-(phenoxymethyl)-benzaldehyde A20 (0.114 g, 0.539 mmol) were dissolved in MeOH (10 mL) and activated 3 sieves (0.526 g) were added. The reaction mixture was then heated at reflux for 20 hours. The mixture was then cooled to room temperature, the solution was decanted from the sieves and the solvent was removed in vacuo. Tetrahydrofuran (10 mL) followed by (Diacetoxyiodo)benzene (0.208 g, 0.646 mmol) were added under an atmosphere of nitrogen and the reaction was stirred at room temperature for 3 hours. The reaction was concentrated in vacuo and diluted with EtOAc (100 mL) and saturated aqueous NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL), the combined organics were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (24 g silica Cartridge, 0-40% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.095 g, 28% over 2 steps) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.50 (br s, 1H), 8.26-8.15 (m, 2H), 7.96 (d, J=7.9 Hz, 1H), 7.62 (d, J=8.0 Hz, 2H), 7.37-7.26 (m, 2H), 7.20 (d, J=8.2 Hz, 1H), 7.09-7.00 (m, 2H), 6.95 (tt, J=7.3, 1.1 Hz, 1H), 5.19 (s, 2H), 4.15 (br s, 1H), 4.04-3.95 (m, 1H), 3.08-2.70 (m, 3H), 2.06-1.99 (m, 1H), 1.83-1.69 (m, 2H), 1.56-1.32 (m, 10H). LCMS-A rt 6.55 min, m/z (positive ion) 485.3 [M+H].sup.+.
Example 35: Synthesis of 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-3-yl)-3H-imidazo[4,5-b]pyridine (35)
(236) ##STR00077##
(237) tert-Butyl 3-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate 34 (0.088 g, 0.18 mmol) was dissolved in DCM (7 mL) under an atmosphere of nitrogen and trifluoroacetic acid (0.348 mL, 4.54 mmol) was added and the resulting mixture was stirred at room temperature for 20 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (70 mL) and 2 M aqueous NaOH (70 mL), the layers were separated and the aqueous layer was extracted with EtOAc (50 mL), the combined organics were washed with brine (50 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The solid was dissolved in DCM (5 mL) and the solution was concentrated in vacuo to give the title compound (0.064 g, 92%) as a beige solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.25-8.18 (m, 2H), 7.91 (d, J=8.2 Hz, 1H), 7.62 (d, J=8.1 Hz, 2H), 7.34-7.27 (m, 2H), 7.14 (d, J=8.2 Hz, 1H), 7.07-7.01 (m, 2H), 6.95 (tt, J=7.3, 1.1 Hz, 1H), 5.19 (s, 2H), 3.13-3.04 (m, 1H), 3.00-2.91 (m, 1H), 2.86 (tt, J=11.1, 3.6 Hz, 1H), 2.75-2.63 (m, 1H), 2.55-2.44 (m, 1H, obscured by DMSO peak), 2.02-1.93 (m, 1H), 1.84-1.64 (m, 2H), 1.50 (qt, J=12.8, 3.9 Hz, 1H). NH protons not observed. LCMS-A rt 4.72 min, m/z (positive) 385.2 [M+H].sup.+.
Example 36: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(pyridin-3-yl)-3H-imidazo[4,5-b]pyridine (36)
(238) ##STR00078##
a) 5-Nitro-[2,3-bipyridin]-6-amine (A82)
(239) A mixture of 2-amino-3-nitro-6-chloropyridine A44 (0.10 g, 0.58 mmol), Na.sub.2CO.sub.3 (0.244 g, 2.31 mmol), pyridin-3-ylboronic acid A81 (0.092 g, 0.75 mmol) and PdCl.sub.2(dppf) DCM solvate (0.036 g, 0.043 mmol) in dioxane (4.75 mL) and H.sub.2O (0.25 mL) was degassed for 10 mins under a stream of nitrogen. The mixture was irradiated in the microwave at 120 C. for 20 minutes. The cooled mixture was concentrated under reduced pressure and purified by silica gel chromatography (silica 24 g cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a yellow-brown solid (0.053 g, 43%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 9.29 (dd, J=2.4, 0.9 Hz, 1H), 8.70 (dd, J=4.7, 1.6 Hz, 1H), 8.49 (d, J=8.7 Hz, 1H), 8.45 (ddd, J=8.0, 2.3, 1.6 Hz, 1H), 8.03 (brs, 2H), 7.56 (ddd, J=8.0, 4.8, 0.9 Hz, 1H), 7.42 (d, J=8.7 Hz, 1H). LCMS-A rt 4.69 min, m/z (positive ion) 217.2 [M+H].sup.+.
b) 2-(4-(Benzyloxy)phenyl)-5-(pyridin-3-yl)-3H-imidazo[4,5-b]pyridine (36)
(240) A mixture of 4-(benzyloxy)benzaldehyde A8 (0.052 g, 0.25 mmol), 5-nitro-[2,3-bipyridin]-6-amine A82 (0.053 g, 0.25 mmol), Na.sub.2S.sub.2O.sub.4 (0.128 g, 0.734 mmol) in MeOH (4 mL) and H.sub.2O (0.73 mL) in a sealed tube was irradiated in the microwave at 110 C. for 15 minutes. The reaction mixture was cooled to room temperature, aqueous ammonia added (0.4 mL), then filtered. The filtrate was evaporated under reduced pressure, then purified by silica gel chromatography (silica 24 g cartridge, 0-10% MeOH in EtOAc) to give the title compound as a yellow solid (0.009 g, 10%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 9.30 (d, J=2.3 Hz, 1H), 8.62-8.57 (m, 1H), 8.47-8.42 (m, 1H), 8.23-8.18 (m, 2H), 8.06-8.00 (m, 1H), 7.84 (d, J=8.4 Hz, 1H), 7.55-7.32 (m, 6H), 7.20 (d, J=8.4 Hz, 2H), 5.21 (s, 2H). Amine proton not seen. LCMS-A: rt 5.03 min, m/z (positive ion) 379.2 [M+H].sup.+.
Example 37: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(pyridin-4-yl)-3H-imidazo[4,5-b]pyridine (37)
(241) ##STR00079##
a) 5-Nitro-[2,4-bipyridin]-6-amine (A84)
(242) A mixture of 2-amino-3-nitro-6-chloropyridine A44 (0.20 g, 1.1 mmol), Na.sub.2CO.sub.3 (0.489 g, 4.61 mmol), pyridin-4-ylboronic acid A83 (0.184 g, 1.50 mmol) and PdCl.sub.2(dppf) DCM solvate (0.071 g, 0.086 mmol) in dioxane (9.5 mL) and H.sub.2O (0.5 mL) was degassed for 10 minutes under a stream of nitrogen. The mixture was irradiated in the microwave at 120 C. for 50 minutes. The cooled mixture was diluted with EtOAc, adsorbed onto silica gel then purified by silica gel chromatography (silica 40 g cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.), to give the title compound as a yellow-brown solid (0.161 g, 65%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.77-8.72 (m, 2H), 8.52 (d, J=8.6 Hz, 1H), 8.07-7.97 (m, 4H), 7.45 (d, J=8.6 Hz, 1H). LCMS-A: rt 4.33 min, m/z (positive ion) 217.1 [M+H].sup.+.
b) [2,4-Bipyridine]-5,6-diamine (A85)
(243) A suspension of 10% Pd/C (0.020 g, 0.19 mmol) in EtOH (35 mL) and 5-nitro-[2,4-bipyridin]-6-amine A84 (0.161 g, 0.75 mmol) in EtOAc (35 mL) was stirred under hydrogen (1 atm) at room temperature for 5 hours. The resulting mixture was filtered through celite, washing with EtOH and EtOAc. The filtrate was evaporated to dryness to give the title compound as lilac crystals (0.141 g, quant); .sup.1H NMR (400 MHz, CD.sub.3OD) 8.52-8.41 (m, 2H), 7.93-7.81 (m, 2H), 7.22 (d, J=7.9 Hz, 1H), 6.96 (d, J=7.8 Hz, 1H). Amine proton not seen. LCMS-A: rt 1.11 min, m/z (positive ion) 187.2 [M+H].sup.+.
c) 2-(4-(Benzyloxy)phenyl)-5-(pyridin-4-yl)-3H-imidazo[4,5-b]pyridine (37)
(244) A mixture of 4-(benzyloxy)benzaldehyde A8 (0.161 g, 0.757 mmol), [2,4-bipyridine]-5,6-diamine A85 (0.141 g, 0.757 mmol), activated molecular sieves 3 (400 mg) and acetic acid (26 drops) in dry MeOH (10 mL) under an atmosphere of nitrogen was stirred at 60 C. for 20 hours. The volatiles were removed in vacuo, and the residue dissolved in THF (6 mL). PhI(OAc).sub.2 (0.244 g, 0.757 mmol) was added then stirred at room temperature for 4.5 hours. The volatiles were removed in vacuo, the residue dissolved in EtOAc, washed with saturated aqueous NaHCO.sub.3, extracted with EtOAc. The organic layers were combined then washed with saturated aqueous NaCl. The organic layer was dried over Na.sub.2SO.sub.4, filtered, evaporated under reduced pressure, then purified using silica gel chromatography (24 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.), to give the title compound as a peach powder (0.038 g, 13%); .sup.1H NMR (400 MHz, CD.sub.3OD) 8.65-8.59 (m, 2H), 8.17-8.14 (m, 2H), 8.11-8.06 (m, 2H), 8.03 (d, J=8.4 Hz, 1H), 7.94 (d, J=8.4 Hz, 1H), 7.49-7.44 (m, 2H), 7.39 (ddd, J=7.9, 7.0, 1.0 Hz, 2H), 7.36-7.29 (m, 1H), 7.20-7.15 (m, 2H), 5.18 (s, 2H). Amine proton not seen. LCMS-A: rt 4.86 min, m/z (positive ion) 379.2[M+H].sup.+, m/z (negative ion) 377.2 [MH].sup..
Example 38: Synthesis of 5-(1-methyl-1H-pyrazol-3-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (38)
(245) ##STR00080##
a) 6-(1-Methyl-1H-pyrazol-3-yl)-3-nitropyridin-2-amine (A87)
(246) A mixture of 2-amino-3-nitro-6-chloropyridine A44 (0.20 g, 1.1 mmol), Na.sub.2CO.sub.3 (0.489 g, 4.61 mmol), 1-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole A86 (0.312 g, 1.50 mmol) and PdCl.sub.2(dppf) DCM solvate (0.072 g, 0.086 mmol) in dioxane (9.5 mL) and H.sub.2O (0.5 mL) was degassed for 10 minutes under a stream of nitrogen. The mixture was irradiated in the microwave at 120 C. for 50 minutes. The cooled mixture was evaporated under reduced pressure, then purified by silica gel chromatography (40 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a yellow solid (0.155 g, 61%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.42 (d, J=8.8 Hz, 1H), 8.09 (br. s, 2H), 7.52 (d, J=2.0 Hz, 1H), 7.16 (d, J=8.8 Hz, 1H), 7.00 (d, J=2.0 Hz, 1H), 4.23 (s, 3H). LCMS-A: rt 5.63 min, m/z (positive ion) 220.1 [M+H].sup.+.
b) 6-(1-Methyl-1H-pyrazol-3-yl)pyridine-2,3-diamine (A88)
(247) A suspension of 10% Pd/C (0.020 g) and 6-(1-methyl-1H-pyrazol-3-yl)-3-nitropyridin-2-amine A87 (0.155 g, 0.707 mmol) in EtOAc (35 mL) and EtOH (35 mL) was stirred under hydrogen (1 atm) at room temperature for 5 hours. The resulting mixture was filtered through celite, washing with EtOAc. The filtrate was evaporated to dryness to give the title compound as purple crystals (0.138 g, quant). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 7.31 (d, J=1.8 Hz, 1H), 6.74 (s, 2H), 6.36 (d, J=1.9 Hz, 1H), 5.56 (s, 2H), 4.92 (s, 2H), 4.05 (s, 3H). LCMS-A: rt 2.20 min, m/z (positive ion) 190.2 [M+H].sup.+.
c) 5-(1-Methyl-1H-pyrazol-3-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (38)
(248) A mixture of 4-(benzyloxy)benzaldehyde A8 (0.155 g, 0.729 mmol), 6-(1-methyl-1H-pyrazol-3-yl)pyridine-2,3-diamine A88 (0.138 g, 0.729 mmol), activated 3 molecular sieves (400 mg) in dry MeOH (8 mL) under an atmosphere of N.sub.2 was stirred at 60 C. for 18 hours, acetic acid (0.4 mL) was added, then stirred for a further 7 hours. The volatiles were removed in vacuo, and the residue dissolved in THF (6 mL). PhI(OAc).sub.2 (0.235 g, 0.729 mmol) was added and the mixture stirred at room temperature for 22 hours. The volatiles were removed in vacuo, the residue dissolved in EtOAc, washed with saturated aqueous NaHCO.sub.3, which was then extracted with EtOAc. The organic layers were combined then washed with saturated aqueous NaCl. The organic layer was dried over Na.sub.2SO.sub.4, filtered, evaporated under reduced pressure, then purified using silica gel chromatography (24 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.), to give a yellow oil. The residue was dissolved in DCM and evaporated under reduced pressure to give the title compound as a pale yellow solid (0.133 g, 48%). .sup.1H NMR (400 MHz, CD.sub.3OD) 8.14-8.06 (m, 2H), 8.00 (d, J=8.3 Hz, 1H), 7.65 (d, J=8.3 Hz, 1H), 7.51 (d, J=2.1 Hz, 1H), 7.49-7.45 (m, 2H), 7.39 (ddd, J=8.0, 7.0, 1.0 Hz, 2H), 7.36-7.30 (m, 1H), 7.22-7.15 (m, 2H), 6.72 (d, J=2.1 Hz, 1H), 5.20 (s, 2H), 4.27 (s, 3H). Amine proton not seen. LCMS-A: rt 5.94 min, m/z (positive ion) 382.2 [M+H].sup.+.
Example 39: Synthesis of tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (39)
(249) ##STR00081##
a) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[2,4-bipyridine]-1(2H)-carboxylate (A46)
(250) tert-Butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1 (2H)-carboxylate (2.333 g, 7.490 mmol) and 2-amino-6-chloro-3-nitropyridine A44 (1.00 g, 5.762 mmol) were dissolved in dry 1,4-dioxane (50 mL), then nitrogen gas was bubbled through the solution for 10 minutes. TBAB (0.186 g, 0.576 mmol), Pd(dppf)Cl.sub.2.DCM (0.238 g, 0.288 mmol) followed by a 3M solution of Na.sub.2CO.sub.3 (1.527 g, 14.404 mmol) in water (4.801 mL) were added and the reaction mixture was heated at 80 C. for 66 hours. The reaction mixture was filtered through celite, washed with EtOAc (520 mL) then concentrated in vacuo to give a brown solid. The crude material was purified by silica gel chromatography (120 g silica cartridge, 0-16% EtOAc in DCM) to give the title compound (1.653 g, 90%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.33 (d, J=8.8 Hz, 1H), 7.87 (s, 2H), 6.96 (d, J=8.8 Hz, 1H), 6.85 (s, 1H), 4.07 (s, 2H), 3.50 (t, J=5.7 Hz, 2H), 2.56-2.50 (m, 2H), 1.42 (s, 9H). LCMS-A rt 6.596 min, m/z (positive ion) 265.1 [M-C.sub.4H.sub.9+2H].sup.+
b) tert-Butyl 4-(5,6-diaminopyridin-2-yl)piperidine-1-carboxylate (A89)
(251) tert-Butyl 6-amino-5-nitro-5,6-dihydro-[2,4-bipyridine]-1(2H)-carboxylate (A46) (0.364 g, 1.136 mmol) was dissolved in EtOH (150 mL) and EtOAc (150 mL) and 10% Pd/C (50% wet with water, 0.365 g) was added and the suspension was stirred under an atmosphere of hydrogen (5 bar) for 18 hours. The mixture was filtered through celite, and the celite was washed with EtOAc (200 mL). The pooled filtrates were evaporated to give the title compound (0.350 g, >99%) as a brown solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 6.85 (d, J=7.7 Hz, 1H), 6.45 (d, J=7.7 Hz, 1H), 4.20 (br s, 4H), 2.79 (t, J=11.6 Hz, 2H), 2.64-2.50 (m, 1H), 1.86 (d, J=13.4 Hz, 2H), 1.73-1.54 (m, overlaps with water signal, 4H), 1.47 (s, 9H). LCMS-A rt 4.181 min, m/z (positive ion) 237.2 [M-tBu+2H].sup.+
(c) tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (39)
(252) tert-Butyl 4-(5,6-diaminopyridin-2-yl)piperidine-1-carboxylate A89 (261 mg, 0.89 mmol), 4-(benzyloxy)benzaldehyde A8 (208 mg, 0.98 mmol) and water (20 mL) were heated at reflux under air. After 66 hours the mixture was cooled and diluted with EtOAc (20 mL) and brine (10 mL). The aqueous phase was extracted with further EtOAc (220 mL), the combined organic extracts washed with brine (50 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. The mixture was dissolved in DCM (10 mL) and treated with PhI(OAc).sub.2 (288 mg, 0.89 mmol). After 19 hours the mixture was diluted with MeOH (10 mL) and loaded onto a 5 g SCX cartridge. The cartridge was washed with DCM (20 mL), 1:1 DCM:MeOH (20 mL), and MeOH (40 mL). The cartridge was eluted with 1:9 concentrated aqueous ammonia:MeOH (60 mL), and the basic eluent evaporated. Column chromatography (4 g silica cartridge, 5-100% EtOAc/hexanes) gave the title compound as a pale yellow solid (44 mg, 10%). .sup.1H NMR (400 MHz, CDCl.sub.3) 10.16 (s, 1H), 8.01-7.94 (m, 3H), 7.47-7.32 (m, 5H), 7.10 (dd, J=8.5, 3.5 Hz, 3H), 5.14 (s, 2H), 4.27 (br s, 2H), 2.95-2.75 (m, 3H), 1.93 (d, J=12.5 Hz, 2H), 1.78 (qd, J=12.8, 4.2 Hz, 2H), 1.49 (s, 9H). LCMS-A: rt 5.24 min, m/z (positive ion) 485.3 [M+H].sup.+, 429.2 [M-tBu+2H].sup.+, m/z (negative ion) 483.2 [MH].sup..
Example 40: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (40)
(253) ##STR00082##
(254) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate 39 (42 mg, 0.09 mmol), DCM (4 mL) and TFA (1 mL) were stirred at room temperature. After 4 hours the mixture was diluted with saturated aqueous NaHCO.sub.3 (20 mL) and the pH brought to 10 with NaOH. The mixture was extracted with EtOAc (330 mL), and the combined EtOAc phases washed with brine (50 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. The residue was sonicated in ether (2 mL), the ether decanted and the solid dried under vacuum to give the title compound as a yellow solid (26 mg, 78%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.07 (br s, 1H), 8.18-8.12 (m, 2H), 7.92 (s, 1H), 7.52-7.45 (m, 2H), 7.44-7.39 (m, 2H), 7.38-7.32 (m, 1H), 7.19 (d, J=8.4 Hz, 2H), 7.12 (d, J=8.2 Hz, 1H), 5.21 (s, 2H), 3.10-2.93 (m, overlaps with water), 2.06-1.92 (m, 4H). LCMS-A: 4.30 min; m/z (positive ion): 385.3 [M+H].sup.+; m/z (negative ion) 383.1 [MH].sup..
Example 41: Synthesis of 2-(4-(benzyloxy)phenyl)-5,7-dichloro-1H-imidazo[4,5-b]pyridine (41)
(255) ##STR00083##
a) 4,6-Dichloro-3-nitropyridin-2-amine (A91)
(256) To 2-amino-4,6-dichloropyridine (1.0 g, 6.1 mmol) was added concentrated H.sub.2SO.sub.4 (5.4 mL) dropwise at 0 C. and the mixture stirred for 10 minutes. To this stirring solution was added concentrated fuming HNO.sub.3 (0.3 mL) dropwise, and the mixture stood at 4 C. for five days. The reaction mixture was poured onto crushed ice then neutralized with NaHCO.sub.3. The resulting precipitate was filtered, washed with H.sub.2O and dried to give the crude product as a yellow powder. The crude product was adsorbed onto silica gel then purified using silica gel chromatography twice (24 g silica cartridge, 0-10% MeOH in DCM then 0-5% MeOH in DCM), evaporated under reduced pressure, then dried to give the title compound as a bright yellow powder (0.744 g, 58%); .sup.1H NMR (400 MHz, CDCl.sub.3): 6.83 (s, 1H), 6.24 (br. s, 2H). LCMS-A: rt 6.21 min, m/z (positive ion) 208.1 [M+H].sup.+.
b) 4,6-Dichloropyridine-2,3-diamine (A92)
(257) To a stirred suspension of 4,6-dichloro-3-nitropyridin-2-amine A91 (0.51 g, 2.5 mmol) in a mixture of water (11 mL) and propan-2-ol (22 mL) was added iron powder (0.68 g, 12 mmol) followed by NH.sub.4Cl (0.64 g, 12.2 mmol) at room temperature and the mixture was then heated to 70 C. for 2 hours. The cooled reaction mixture was filtered through celite and washed with EtOAc (150 mL). The resulting solution was washed with saturated aqueous NaHCO.sub.3, brine, dried over Na.sub.2SO.sub.4, filtered and evaporated under reduced pressure then dried to give the title compound as light brown crystals (0.39 g, 89%); .sup.1H NMR (400 MHz, CDCl.sub.3) 6.76 (s, 1H), 4.44 (s, 2H), 3.56 (s, 2H). LCMS-A: rt 5.53 min, m/z (positive ion) 178.1 [M+H].sup.+.
c) 2-(4-(Benzyloxy)phenyl)-5, 7-dichloro-1H-imidazo[4,5-b]pyridine (41)
(258) A suspension of 4,6-dichloropyridine-2,3-diamine A92 (0.39 g, 2.2 mmol) and 4-(benzyloxy)benzaldehyde A8 (0.465 g, 2.19 mmol) in MeOH (10 mL) was irradiated in the microwave at 120 C. for 15 minutes. The volatiles were removed in vacuo and the residue dissolved in THF (10 mL). PhI(OAc).sub.2 (0.706 g, 2.19 mmol) was added and the resulting mixture stirred for 18 hours at room temperature. The volatiles were removed in vacuo, the residue suspended in saturated aqueous NaHCO.sub.3 (25 mL), extracted into DCM (100 mL) then adsorbed onto silica gel and purified using silica gel chromatography (40 g silica cartridge, 0-100% EtOAc in cyclohexane), solvent evaporated under reduced pressure, then dried to give the title compound as a fawn coloured solid (0.083 g, 10%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.18 (d, J=8.0 Hz, 2H), 7.53 (s, 1H), 7.51-7.44 (m, 2H), 7.45-7.31 (m, 3H), 7.25-7.13 (m, 2H), 5.22 (s, 2H). Amine proton not seen; LCMS-A: rt 6.79 min, m/z (positive ion) 370.0 [M+H].sup.+; m/z (negative ion) 368.0 [MH].sup..
Example 42: Synthesis of 7-chloro-2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-1H-imidazo[4,5-b]pyridine (42)
(259) ##STR00084##
a) tert-Butyl 6-amino-4-chloro-5-nitro-5,6-dihydro-[2,4-bipyridine]-1(2H)-carboxylate (A94)
(260) To a mixture of 4,6-dichloropyridine-2,3-diamine A91 (1.24 g, 5.96 mmol) in dioxane (36 mL) and H.sub.2O (1.8 mL) was added Na.sub.2CO.sub.3 (2.527 g, 23.84 mmol) followed by tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate A26 (2.393 g, 7.74 mmol). The resulting mixture was degassed for 10 mins under a stream of nitrogen. PdCl.sub.2(dppf) DCM solvate (0.260 g, 0.447 mmol) was added, then the mixture was heated to 100 C. for 24 hours. The cooled mixture was evaporated under reduced pressure, the residue dissolved in DCM, adsorbed onto silica then purified by silica gel chromatography (40 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) gave the title compound as bright yellow crystals (0.225 g, 11%); .sup.1H NMR (400 MHz, CDCl.sub.3) 6.53 (s, 1H), 6.45 (br. s, 2H), 5.65 (br. s, 1H), 4.03 (s, 2H), 3.62 (d, J=5.4 Hz, 2H), 2.26 (br. s, 2H), 1.49 (s, 9H). LCMS-A: rt 6.75 min, m/z (positive ion) 255.1 [M-Boc+2H].sup.+; m/z (negative ion) 353.1 [MH].sup..
b) tert-Butyl 4-(5,6-diamino-4-chloropyridin-2-yl)piperidine-1-carboxylate (A95)
(261) A suspension of tert-butyl 6-amino-4-chloro-5-nitro-5,6-dihydro-[2,4-bipyridine]-1(2H)-carboxylate A94 (0.225 g, 0.36 mmol) and platinum(IV) oxide (0.030 g, 0.64 mmol), in DIPEA (6.7 mL) and MeOH (1.4 mL) was stirred under hydrogen (1 atm) for 18 hours. The reaction mixture was filtered through celite, washed with EtOAc, evaporated under reduced pressure, then placed on the freezedrier overnight to give the title compound as a brown solid (0.235 g, quant). LCMS-A rt 6.03 min, 327.2 [M+H].sup.1H NMR (400 MHz, d.sub.6-DMSO) b 6.27 (s, 1H), 5.76 (s, 2H), 4.60 (s, 2H), 4.14-3.92 (m, 2H), 2.89-2.69 (m, 3H), 1.65 (d, J=12.7 Hz, 2H), 1.40 (s, 9H). Two protons obscured by solvent.
c) tert-Butyl 4-(7-chloro-2-(4-(phenoxymethyl)phenyl)-1H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (A96)
(262) A mixture of 4-(phenoxymethyl)benzaldehyde A20 (0.153 g, 0.719 mmol), tert-butyl 4-(5,6-diamino-4-chloropyridin-2-yl)piperidine-1-carboxylate A95 (0.235 g, 0.719 mmol) in MeOH (6 mL), activated 3 molecular sieves (400 mg) and acetic acid (9 drops) under an atmosphere of nitrogen was stirred at 60 C. for 18 hours. The volatiles were removed in vacuo, and the residue dissolved in THF (6 mL). PhI(OAc).sub.2 (0.232 g, 0.719 mmol) was added then stirred at room temperature for 22 hours. The volatiles were removed in vacuo, the residue dissolved in EtOAc, washed with saturated aqueous NaHCO.sub.3, then extracted with EtOAc. The organic layers were combined then washed with saturated aqueous NaCl. The organic layer was dried over Na.sub.2SO.sub.4, filtered, evaporated under reduced pressure, the residue adsorbed onto silica gel then purified using silica gel chromatography (24 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as an off-white powder (0.071 g, 19%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.21 (d, J=8.4 Hz, 2H), 7.63 (d, J=8.0 Hz, 2H), 7.30 (dd, J=8.7, 7.3 Hz, 2H), 7.16 (s, 1H), 7.08-6.99 (m, 2H), 6.98-6.89 (m, 1H), 5.19 (s, 2H), 4.12 (d, J=12.5 Hz, 2H), 2.89 (br. s, 2H), 1.88 (d, J=9.2 Hz, 2H), 1.80 (br. s, 2H), 1.43 (s, 9H). One proton obscured by solvent, amine proton not observed. LCMS-A: rt 7.10 min, m/z (positive ion) 519.2 [M+H].sup.+.
d) 7-Chloro-2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-1H-imidazo[4,5-b]pyridine (42)
(263) tert-Butyl 4-(7-chloro-2-(4-(phenoxymethyl)phenyl)-1H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate A96 (0.071 g, 0.14 mmol) was dissolved in DCM (6 mL) under an atmosphere of nitrogen and trifluoroacetic acid (0.32 mL, 4.1 mmol) was added. The resulting mixture was stirred at room temperature for 18 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (50 mL) and 2 M aqueous NaOH (50 mL). The layers were separated and the aqueous layer was extracted with EtOAc (20 mL), the combined organics were washed with brine (20 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound as a pale yellow solid (0.053 g, 93%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.23 (d, J=8.3 Hz, 2H), 7.61 (d, J=8.3 Hz, 2H), 7.30 (dd, J=8.7, 7.3 Hz, 2H), 7.07-7.01 (m, 3H), 6.99-6.87 (m, 1H), 5.18 (s, 2H), 3.08 (d, J=12.0 Hz, 2H), 2.69 (td, J=12.2, 2.9 Hz, 2H), 1.87-1.67 (m, 4H). One proton obscured by solvent, amine proton not observed. LCMS-A: rt 4.80 min, m/z (positive ion) 419.2 [M+H].sup.+, m/z (negative ion) 417.1 [MH].sup..
Example 43: Synthesis of 7-methyl-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-amine (43)
(264) ##STR00085##
a) 2-Chloro-4-methyl-5-nitropyridine-1-oxide (A98)
(265) A solution of 2-chloro-5-nitro-4-picoline A97 (2.50 g, 14.5 mmol) in DCM (25 mL) was cooled to 0 C. and urea hydrogen peroxide (2.86 g, 30.4 mmol) was added, followed by dropwise addition of trifluoroacetic anhydride (4.10 mL, 29.0 mmol). The mixture stirred at 0 C. for 10 minutes, then allowed to warm to r.t. and stirred for a further 20 hours. The reaction was quenched with water (25 mL), stirred for 20 minutes, then diluted with further water and DCM (50 mL each). The aqueous phase was separated and extracted with DCM (375 mL). The combined organic extracts were washed with saturated NaHCO.sub.3 (100 mL), and the bicarbonate wash back extracted with further DCM (275 mL). The combined organic extracts were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The solid residue was washed with diethyl ether (10 mL) and dried under vacuum to give the title compound as a bright yellow solid (2.53 g, 93%). .sup.1H NMR (400 MHz, CDCl.sub.3): 9.02 (s, 1H), 7.51 (s, 1H), 2.63 (s, 3H). LCMS-B: 2.637 min; m/z (positive ion) 189.0 [M+H].sup.+.
b) 2,6-Dichloro-4-methyl-3-nitropyridine (A99)
(266) 2-Chloro-4-methyl-5-nitropyridine-1-oxide A98 (2.528 g, 13.4 mmol) was stirred in POCl.sub.3 (12.5 mL) at 80 C. After 17 hours, the mixture was cooled and added slowly and cautiously to water (150 mL). Once the exothermic POCl.sub.3 breakdown had finished, the mixture was diluted with ice (50 g), neutralised with solid NaHCO.sub.3, diluted with further water (75 mL) and extracted with DCM (575 mL). The combined DCM extracts were dried over Na.sub.2SO.sub.4 then concentrated in vacuo. The crude material was purified by silica gel chromatography (40 g silica cartridge, 0-80% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a yellow oil (778 mg, 28%). .sup.1H NMR (400 MHz, CDCl.sub.3): 7.28 (q, J=0.8 Hz, 1H), 2.38 (d, J=0.7 Hz, 3H). LCMS-B: rt 3.44 min, no product ions detected.
c) 4-Methyl-3-nitropyridine-2,6-diamine (A100)
(267) To 2,6-dichloro-4-methyl-3-nitropyridine A99 (100 mg, 0.483 mmol) was added 29% w/w aqueous ammonia (1.0 mL, 16 mmol). The mixture was irradiated in a microwave reactor at 130 C. for 30 minutes. The mixture was cooled, diluted with water (1.0 mL) and the precipitate filtered to give a brown solid. The solid was purified by silica gel chromatography (12 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.035 g, 43%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO): 7.64 (br s, 2H), 6.97 (brs, 2H), 5.74 (d, J=1.0 Hz, 1H), 2.39 (d, J=0.9 Hz, 3H). LC-MS: rt 2.67 min, m/z (positive ion) 168.2 [M+H].sup.+.
d) 7-Methyl-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-amine (43)
(268) To a suspension of 4-(phenoxymethyl)benzaldehyde A20 (0.015 g, 0.072 mmol) and 4-methyl-3-nitropyridine-2,6-diamine A100 (0.011 g, 0.065 mmol) in EtOH (0.325 mL) was added 1 M aqueous Na.sub.2S.sub.2O.sub.4 solution (0.196 mL, 0.196 mmol). The resulting yellow suspension was irradiated in a microwave reactor at 110 C. for 15 minutes. The reaction was cooled to room temperature then 28% w/w aqueous NH.sub.3 (1 mL) was added and the reaction mixture was stirred for 5 minutes. The solution was filtered to give a yellow solid. The solid was purified by silica gel chromatography (4 g silica Cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-10% MeOH in EtOAc) to give the title compound (0.004 g, 19%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-acetone): 11.64 (br s, 1H), 8.20 (d, J=8.3 Hz, 2H), 7.60 (d, J=8.0 Hz, 2H), 7.37-7.24 (m, 2H), 7.05 (d, J=8.2 Hz, 2H), 6.95 (t, J=7.3, 7.3 Hz, 1H), 6.33 (s, 1H), 5.24 (brs, 1H), 5.22 (br s, 1H), 5.19 (s, 2H), 2.48 (s, 3H). LCMS-B: rt 3.08 min, m/z (positive ion) 331.2 [M+H].sup.+.
Example 44: Synthesis of (4-(5-chloro-3H-imidazo[4,5-b]pyridin-2-yl)phenyl)(phenyl)MeOH (44)
(269) ##STR00086##
a) (4-(5-Chloro-3H-imidazo[4,5-b]pyridin-2-yl)phenyl)(phenyl)methanone (A101)
(270) HATU (0.924 g, 2.43 mmol) was added to a solution of the 6-chloropyridine-2,3-diamine A45 (0.317 g, 2.21 mmol), 4-benzoylbenzoic acid (0.500 g, 2.21 mmol) and DIPEA (1.16 mL, 6.63 mmol) in MeCN (40 mL) and the resulting solution stirred at 40 C. for 18 hours. The mixture was diluted with saturated aqueous NaHCO.sub.3 (100 mL) and extracted with EtOAc (3100 mL). The combined organic extracts were washed with saturated brine (150 mL), dried (Na.sub.2SO.sub.4), filtered and the volatiles removed in vacuo to give a brown solid. The solid was dissolved in acetic acid (6 mL) and heated under microwave irradiation at 140 C. for 1 hour. The volatiles were removed in vacuo and the residue treated with saturated aqueous NaHCO.sub.3 (100 mL) and extracted with EtOAc (3100 mL). The combined organic extracts were washed with brine (150 mL), dried (Na.sub.2SO.sub.4), filtered and the volatiles removed in vacuo to give a brown semi-solid which was purified by silica gel chromatography (40 g silica cartridge eluting with 0-70% EtOAc in petroleum benzine 40-60 C.) to give a pale yellow solid which was sonicated in diethyl ether (15 mL) and the supernatant carefully removed and discarded. The resulting solid was dried in vacuo to give the title compound as a white solid (0.086 g, 12%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.84 (s, 1H), 8.38 (d, J=8.5 Hz, 2H), 8.11 (d, J=8.3 Hz, 1H), 7.93 (d, J=8.4 Hz, 2H), 7.81-7.77 (m, 2H), 7.74-7.69 (m, 1H), 7.60 (t, J=7.6 Hz, 2H), 7.35 (d, J=8.3 Hz, 1H). LCMS-A rt 6.15 min, m/z (positive ion) 334, 336 [M+H].sup.+.
b) (4-(5-Chloro-3H-imidazo[4,5-b]pyridin-2-yl)phenyl)(phenyl)MeOH (44)
(271) NaBH.sub.4 (0.024 g, 0.63 mmol) was added to a solution of (4-(5-chloro-3H-imidazo[4,5-b]pyridin-2-yl)phenyl)(phenyl)methanone A101 (0.070 g, 0.21 mmol) in MeOH (5 mL) and DCM (1 mL) and the resulting mixture stirred at room temperature for 2 hours. The volatiles were removed in vacuo and the residue dissolved in EtOAc (25 mL) and washed with 2 M aqueous HCl (25 mL), saturated aqueous NaHCO.sub.3 (25 mL), brine (25 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated under reduced pressure to give a white solid which was purified by silica gel chromatography (12 g silica cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a white solid (0.036 g, 51%); .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.52 (s, 1H), 8.13 (d, J=8.3 Hz, 2H), 8.02 (d, J=8.2 Hz, 1H), 7.57 (d, J=8.3 Hz, 2H), 7.44-7.39 (m, 2H), 7.34-7.27 (m, 3H), 7.24-7.18 (m, 1H), 6.03 (d, J=4.0 Hz, 1H), 5.78 (d, J=3.7 Hz, 1H). LCMS-A rt 5.77 min, m/z (positive ion) 336, 338 [M+H].sup.+.
Example 45: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine (45)
(272) ##STR00087##
a) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-5,6-dihydropyridine-1(2H)-carboxylate (A102)
(273) 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine (17) (100 mg, 0.30 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (276 mg, 0.89 mmol), PdCl.sub.2(dppf) DCM solvate (62 mg, 25 mol %) and DMF (5 mL) were stirred under nitrogen. A solution of Na.sub.2CO.sub.3 (284 mg, 2.68 mmol) in water (1.5 mL) was added, the mixture degassed with bubbling nitrogen and heated to 80 C. under nitrogen. After 17 hours the mixture was cooled and added to EtOAc (50 mL). The mixture was filtered through celite, the celite washed with further EtOAc (50 mL) and the filtrate concentrated. Column chromatography (12 g silica cartridge, 0-100% EtOAc/hexanes) and collection of the suspected product fractions gave tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-5,6-dihydropyridine-1(2H)-carboxylate as a white solid (93 mg, 64%). .sup.1H NMR (400 MHz, DMSO) 13.26 (br s, 1H), 8.19-8.12 (m, 2H), 7.91 (d, J=8.3 Hz, 1H), 7.52-7.31 (m, 5H), 7.22-7.16 (m, 2H), 6.64 (s, 1H), 5.21 (s, 2H), 4.07 (s, 2H), 3.57 (t, J=5.6 Hz, 2H), 2.69-2.62 (m, 2H), 1.44 (s, 9H). LCMS-A rt 6.25 min; m/z (positive ion) 483.3 [M+H].sup.+; m/z (negative ion) 481.2 [MH].sup..
b) 2-(4-(Benzyloxy)phenyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine (45)
(274) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-5,6-dihydropyridine-1(2H)-carboxylate (92 mg, 0.19 mmol), DCM (4 mL) and TFA (1 mL) were stirred at room temperature for 18 hours. The mixture was quenched with saturated aqueous K.sub.2CO.sub.3 until pH 11 was reached, the volatiles were removed on a rotary evaporator and the residue diluted with water (10 mL). The precipitate was collected, dissolved in MeOH and applied to a 10 g SCX cartridge. The cartridge was washed with MeOH (100 mL) and eluted with 9:1 MeOH:concentrated aqueous ammonia. The basic eluent was concentrated, and the residue evaporated from absolute EtOH twice to give the title compound as an off-white solid (19 mg, 26%). .sup.1H NMR (400 MHz, DMSO) 8.16 (d, J=8.4 Hz, 2H), 7.91 (d, J=8.4 Hz, 1H), 7.51-7.33 (m, 5H), 7.19 (d, J=8.4 Hz, 2H), 6.68 (s, 1H), 5.20 (s, 2H), 3.53 (s, overlaps with water), 3.05 (s, 2H), 2.61 (s, 2H). NH protons not visible. LCMS-A: rt 4.66 min; m/z (positive ion) 383.2 [M+H].sup.+; m/z (negative ion) 381.1 [MH].sup..
Example 46: Synthesis of (R)-2-amino-1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)propan-1-one (46)
(275) ##STR00088##
a) (R)-tert-Butyl (1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)-1-oxopropan-2-yl)carbamate (A104)
(276) 2-(4-(Benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 40 (30 mg, 0.078 mmol), (R)-2,5-dioxopyrrolidin-1-yl 2-((tert-butoxycarbonyl)amino)propanoate A103 (34 mg, 0.12 mmol) and DMF (0.5 mL) were mixed and stood at room temperature. After 16 hours the mixture was added to water (20 mL) and extracted with EtOAc (320 mL). The combined EtOAc phases were washed with water (40 mL), brine (340 mL), dried over Na.sub.2SO.sub.4, filtered and evaporated. Column chromatography (4 g silica cartridge, 0-100% EtOAc/hexanes) and collection of the suspected product fractions gave (R)-tert-butyl (1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)-1-oxopropan-2-yl)carbamate as a colourless syrup (26 mg, 60%). LCMS: rt 5.60 min; m/z (positive ion) 556.3 [M+H].sup.+, 456.2 [M-Boc+2H].sup.+; m/z (negative ion) 554.3 [MH].sup.1H NMR (400 MHz, CDCl.sub.3) 10.48 (s, 1H), 8.11-7.91 (m, 3H), 7.48-7.31 (m, 5H), 7.14-7.02 (m, 3H), 5.80 (d, J=7.9 Hz, 1H), 4.81-4.62 (m, 2H), 4.01 (d, J=13.4 Hz, 1H), 3.28-3.11 (m, 1H), 3.09-2.95 (m, 1H), 2.76 (q, J=11.5 Hz, 1H), 2.11-1.95 (m, overlaps with trace solvent), 1.94-1.77 (m, overlaps with water), 1.42 (d, J=6.4 Hz, 9H), 1.35 (dd, J=15.5, 6.8 Hz, 3H).
b) (R)-2-Amino-1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)propan-1-one (46)
(277) (R)-tert-butyl (1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)-1-oxopropan-2-yl)carbamate (25 mg, 0.045 mmol), DCM (4 mL) and TFA (2 mL) were stood for two hours. The mixture was quenched with saturated aqueous K.sub.2CO.sub.3 (20 mL) and the volatiles solvents removed on a rotary evaporator. The aqueous residue was diluted with water (10 mL) and extracted with EtOAc (320 mL). The combined organic extracts were dried over Na.sub.2SO.sub.4, filtered and evaporated to give (R)-2-amino-1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidin-1-yl)propan-1-one as a colourless glass (36 mg).
(278) LCMS: rt 4.58 min; m/z (positive ion) 456.3 [M+H].sup.+, 385.2 [M-Ala+2H].sup.+; m/z (negative ion) 454.3 [MH].sup.1H NMR (400 MHz, DMSO) 8.17-8.12 (m, 2H), 7.86 (d, J=8.1 Hz, 1H), 7.51-7.46 (m, 2H), 7.45-7.39 (m, 2H), 7.38-7.33 (m, 1H), 7.18 (d, J=8.9 Hz, 2H), 7.10 (d, J=8.1 Hz, 1H), 5.21 (s, 2H), 4.61-4.49 (m, 1H), 4.11-3.99 (m, 1H), 3.80 (q, J=6.6 Hz, 1H), 3.23-3.11 (m, 2H), 3.09-2.99 (m, 1H), 2.75-2.64 (m, 1H), 1.91 (d, J=13.7 Hz, 2H), 1.86-1.50 (m, 3H), 1.15-1.06 (m, 3H).
Example 47: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (47)
(279) ##STR00089##
a) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4, 5-b]pyridin-5-yl)piperazine-1-carboxylate (A106)
(280) A solution of 2-(4-(benzyloxy)phenyl)-5-chloro-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridine A52 (51.3 mg, 110 mol), N-Boc piperazine A105 (24.6 mg, 132 mol), RuPhos ligand (4.8 mg, 10 mol), chloro-(2-dicyclohexylphosphino-2,6-diisopropoxy-1,1-biphenyl)[2-(2-aminoethyl)phenyl]palladium(II)-methyl-t-butyl ether adduct (11.3 mg, 13 mol) and NaOt-Bu (12.6 mg, 131 mol) in THF (1 mL) was evacuated and purged with nitrogen three times. The suspension was heated at 85 C. for 3 hours and then cooled to room temperature. EtOAc (10 mL) and water (5 mL) were added and the layers separated. The aqueous layer was extracted with EtOAc (5 mL). The combined organic layers were dried with Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction product was purified by column chromatography (4 g silica cartridge, 10-80% EtOAc in cyclohexane) to give the title compound as a pale yellow oil (24.7 mg, 36%). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.06-8.02 (m, 2H), 7.88 (d, J=8.7 Hz, 1H), 7.49-7.44 (m, 2H), 7.43-7.38 (m, 2H), 7.37-7.33 (m, 1H), 7.12-7.08 (m, 2H), 6.68 (d, J=8.8 Hz, 1H), 5.57 (s, 2H), 5.14 (s, 2H), 3.90-3.84 (m, 2H), 3.59 (s, 8H) 1.50 (s, 9H), 1.06-0.99 (m, 2H), 0.01 (s, 9H); LCMS-B rt 4.86 min.
b) 2-(4-(Benzyloxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (47)
(281) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A106 (24.7 mg, 40.0 mol) was dissolved in CDCl.sub.3 (2 mL), TFA (1 mL) was added and the mixture stirred for 72 hours. The reaction mixture was concentrated and the residue dissolved in the minimum amount of MeOH. The solution was loaded onto an SCX cartridge (1 g) and washed with MeOH (20 mL). The product was eluted by treating with MeOH:NH.sub.4OH 9:1 to give a pale yellow solid. The solid was further purified by mass-directed prep HPLC to give the title compound as a pale yellow solid (3.2 mg, 20%). .sup.1H NMR (400 MHz, DMSO) 8.27 (s, 1H), 8.06 (d, J=8.9 Hz, 2H), 7.76 (d, J=8.8 Hz, 1H), 7.51-7.45 (m, 2H), 7.45-7.37 (m, 2H), 7.37-7.31 (m, 1H), 7.14 (d, J=8.9 Hz, 1H), 6.75 (d, J=8.9 Hz, 1H), 5.18 (s, 2H), 3.66-3.38 (m, 4H), 2.96-2.87 (m, 4H); LCMS-C rt 4.08 min; m/z (positive ion) 386 [M+H].sup.+.
Example 48: Synthesis of 2-(4-(benzyloxy)phenyl)-N,N-dimethyl-3H-imidazo[4,5-b]pyridin-5-amine (48)
(282) ##STR00090##
(a) N2-(2-(Dimethylamino)ethyl)-5-nitropyridine-2,6-diamine (A108)
(283) General Method A: 2-amino-6-chloro-3-nitropyridine A44 (200 mg, 1.15 mmol), N.sup.1,N.sup.1-dimethylethane-1,2-diamine A107 (122 mg, 1.38 mmol). The orange solution was treated with water (5 mL) and the resulting suspension filtered. The filtrate was extracted with EtOAc (220 mL), washed with brine (5 mL) and concentrated to give the title compound as a yellow powder (114 mg, 44%); LCMS-B rt 1.77 min, m/z (positive ion) 226 [M+H].sup.+ with impurities at 2.89 min, and 3.03 min.
(b) 2-(4-(Benzyloxy)phenyl)-N, N-dimethyl-3H-imidazo[4,5-b]pyridin-5-amine (48)
(284) General Method B: N2-(2-(dimethylamino)ethyl)-5-nitropyridine-2,6-diamine A108 (289 mg, 1.28 mmol). The resulting yellow suspension was heated at 110 C. for 20 minutes in a microwave. The reaction was cooled to room temperature. The reaction mixture was treated with 28% w/w aqueous ammonia (1 mL) and extracted with EtOAc (310 mL). The combined organic layers were washed with water (210 mL), brine (5 mL), dried (MgSO.sub.4) and concentrated in vacuo. The crude material was purified by column chromatography (24 g silica cartridge, 10-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a colourless solid (1.8 mg, 0.4%); .sup.1H NMR (400 MHz, CD.sub.3OD) 7.96 (d, J=8.9 Hz, 2H), 7.71 (d, J=8.8 Hz, 1H), 7.52-7.43 (m, 2H), 7.43-7.35 (m, 2H), 7.35-7.28 (m, 1H), 7.12 (d, J=8.9 Hz, 2H), 6.62 (d, J=8.9 Hz, 1H), 5.17 (s, 2H), 3.31 (s, 6H). LCMS-B rt 3.16 min, m/z (positive ion) 345 [M+H].sup.+, m/z (negative ion) 343 [MH].sup..
Example 49: Synthesis of 2-(4-(benzyloxy)phenyl)-4-methyl-6-(piperidin-4-yl)-1H-benzo[d]imidazole (49)
(285) ##STR00091##
a) N-(4-Bromo-2-methyl-6-nitrophenyl)-2,2,2-trifluoroacetamide (A109)
(286) 4-Bromo-2-methylaniline (1.0 g, 5.4 mmol) was dissolved in DCM (4 mL) and cooled to 0 C. Trifluoroacetic anhydride (2 mL) was added, and the mixture stirred for 30 minutes at 0 C. Potassium nitrate (0.679 g, 6.72 mmol) was added, and the cooling bath removed. After 1 hour the mixture became thick and difficult to stir, the mixture was sonicated for 2 minutes and stirring resumed. After 4 hours the mixture was concentrated by evaporation, and the residue suspended in water (25 mL). The mixture was sonicated for 1 minute, filtered and the collected solid washed with water (330 mL). The solid was air dried to give the title compound as a lemon yellow solid (1.7 g, 96% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.03 (s, 1H), 8.11-8.09 (m, 1H), 7.76 (d, J=2.2 Hz, 1H), 2.33 (s, 3H). LCMS-B: rt 6.46 min, m/z (negative ion) 327.0 [MH].sup. for .sup.81Br
b) 4-Bromo-2-methyl-6-nitroaniline (A110)
(287) N-(4-Bromo-2-methyl-6-nitrophenyl)-2,2,2-trifluoroacetamide A109 (750 mg, 2.29 mmol), potassium carbonate (634 mg, 4.59 mmol), water (10 mL) and MeOH (20 mL) were stirred at 50 C. After 17 hours the mixture was heated to reflux for 1 hour then allowed to cool. The mixture was diluted with water to 100 mL, and the resultant precipitate collected, washed with water (50 mL) and air dried to give the title compound as a bright yellow solid (323 mg, 61% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.21 (d, J=2.2 Hz, 1H), 7.43-7.39 (m, 1H), 6.20 (br s, 2H), 2.26 (s, 3H). LCMS-B rt 6.56 min.
c) tert-Butyl 4-(4-amino-3-methyl-5-nitrophenyl)-3,6-dihydropyridine-1 (2H)-carboxylate (A111)
(288) 4-Bromo-2-methyl-6-nitroaniline A110 (320 mg, 1.39 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,6-dihydropyridine-1(2H)-carboxylate (471 mg, 1.52 mmol) and PdCl.sub.2(dppf) (57 mg, 5 mol %) were loaded into a flask. 1,4-Dioxane (10 mL) was added, followed by a solution of potassium carbonate (383 mg, 2.77 mmol) in water (5 mL). The mixture was degassed by bubbling nitrogen through the reaction mixture then stirred for 17 hours at 80 C. under nitrogen. The cooled mixture was concentrated, the aqueous residue diluted with water (50 mL) and extracted with CHCl.sub.3 (350 mL). The pooled CHCl.sub.3 extracts were washed with brine (50 mL), dried over Na.sub.2SO.sub.4 and evaporated. Column chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) gave the title compound as a viscous orange syrup (321 mg, 70% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.01 (s, 1H), 7.39 (s, 1H), 6.19 (s, 2H), 5.99 (s, 1H), 4.08-4.04 (m, 2H), 3.62 (t, J=5.7 Hz, 2H), 2.51-2.44 (m, 2H), 2.26 (s, 3H), 1.49 (s, 9H). LCMS-B: rt 6.87 min; m/z (positive ion) 278.2 [M-tBu+2H].sup., 234.1 [M-Boc+2H]
d) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-4-methyl-1H-benzo[d]imidazol-6-yl)piperidine-1-carboxylate (A112)
(289) A mixture of tert-butyl 4-(4-amino-3-methyl-5-nitrophenyl)-3,6-dihydropyridine-1(2H)-carboxylate A111 (320 mg, 0.96 mmol) and 10% Pd/C (50% wet with water, 150 mg) in 1:1 EtOAc:96% EtOH (20 mL) was stirred at room temperature under hydrogen. After 90 hours the mixture was filtered through Celite, and the Celite washed with EtOH (50 mL). The filtrate was evaporated under reduced pressure to give a solid residue. A solution of the resultant solid residue and A8 (211 mg, 0.99 mmol) in EtOH (10 mL) was refluxed under air. After 20 hours the mixture was cooled and concentrated in vacuo. Column chromatography (12 g SiO.sub.2 cartridge, 5-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH/EtOAc) then (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to gave the title compound as a pale yellow syrup (42 mg, 9% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.64 (br s, 0.5H), 9.36 (br s, 0.5H), 7.98 (d, J=8.4 Hz, 2H), 7.48-7.31 (m, 5H), 7.07 (d, J=8.8 Hz, 2H), 6.91 (s, 1H), 5.13 (s, 2H), 4.26 (br s, 2H), 2.90-2.77 (m, 2H), 2.77-2.46 (m, 4H), 1.87 (d, J=13.0 Hz, 2H), 1.74-1.61 (m, 4H), 1.50 (s, 9H). NH proton not observed. LCMS-B: rt 5.38 min; m/z (positive ion) 498.3 [M+H].sup.+, m/z (negative ion) 496.3 [MH].sup..
e) 2-(4-(Benzyloxy)phenyl)-4-methyl-6-(piperidin-4-yl)-1H-benzo[d]imidazole (49)
(290) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-4-methyl-1H-benzo[d]imidazol-6-yl)piperidine-1-carboxylate A112 (42 mg, 0.084 mmol), DCM (4 mL) and TFA (1 mL) were stirred for 18 hours at room temperature. The mixture was quenched with saturated potassium carbonate, the volatile solvent removed on a rotary evaporator and the residue extracted with EtOAc (320 mL). The pooled EtOAc phases were dried over Na.sub.2SO.sub.4 and evaporated to give the title compound as a white solid (39 mg, quantitative). LCMS-B: rt 4.42 min; m/z (positive ion) 398.2 [M+H].sup.+; m/z (negative ion) 396.2 [MH].sup.
General Procedure Int1: Preparation of 6-amido-3-nitro-pyridin-2-amines
(291) ##STR00092##
(292) A solution of 6-chloro-3-nitropyridin-2-amine (174 mg, 1.00 mmol), the desired amine (1.20 mmol) and i-Pr.sub.2NEt (0.400 mL, 2.31 mmol) in DMF (2 mL) was heated at 85 C. for 17 hours. The solution was cooled to room temperature and water (4 mL) was added. A precipitate formed and the product was isolated by vacuum filtration, washed with water until the filtrates were clear and air dried to give the desired product.
(293) TABLE-US-00001 TABLE A Product Name and Example Amine Structure LCMS data Method A113
Example 50-55: Synthesis of 5-amidoimidazopyridines
(294) ##STR00097##
(295) General Procedure C:
(296) A suspension of 4-(benzyloxy)benzaldehyde A8 (102 mg, 0.480 mmol), the desired 6-amido-3-nitropyridin-2-amine (0.400 mmol) and sodium dithionate (209 mg, 1.2 mmol) in EtOH (1.6 mL) and water (1.2 mL) was heated at 110 C. for 15 minutes in a microwave. The mixture was cooled to room temperature and 5 M aqueous ammonium hydroxide solution (1 mL) and EtOAc (3 mL) were added. The layers were separated and the aqueous phase was extracted with EtOAc (310 mL). The combined organic layers were washed with brine (5 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The residues were dissolved in the minimum required volume of MeOH and loaded onto an SCX cartridge (10 g) and washed with MeOH (310 mL). The product was then eluted with 2 M ammonia in MeOH (310 mL), the fractions containing product were combined and concentrated in vacuo to give the desired compound.
(297) TABLE-US-00002 TABLE B Amound of Example Int1 Product Name and Structure LCMS data Method A115 135 mg, 0.400 mmol A113
(298) General Procedure D:
(299) The desired Boc-protected amines 28, 29, 31, 32, A115, A116 (see table for amounts) were dissolved in DCM (0.5 mL) and treated with TFA (0.5 mL). The resulting solution was stirred at room temperature for 18 hours before the addition of 2 M NaOH until the solution became basic. The aqueous layer was extracted with EtOAc (33 mL). The combined organic layers were washed with water (3 mL), brine (3 mL), dried over (Na.sub.2SO.sub.4) and concentrated in vacuo. The residue was purified by preparative mass-directed HPLC to give the desired compound.
(300) TABLE-US-00003 TABLE C Amount of Boc- protected Example amines Product Name and Structure LCMS data Method 50 77.8 mg, 0.151 mmol 28
Intermediate A117: Synthesis of tert-butyl 4-(6-amino-5-nitropyridin-2-yl)piperazine-1-carboxylate
(301) ##STR00106##
tert-Butyl 4-(6-amino-5-nitropyridin-2-yl)piperazine-1-carboxylate (A117)
(302) A solution of 2-amino-6-chloro-3-nitropyridine A9 (5.00 g, 28.8 mmol), (N)-Boc-piperazine A105 (6.44 g, 34.6 mmol) and i-Pr.sub.2NEt (10.0 mL, 28.8 mmol) in DMF (50 mL) was heated at 85 C. for 16 hours. The orange solution was treated with water (150 mL), the resulting suspension was filtered and the solid was air dried to give the title compound (9.31 g, 100%) as a yellow powder. LCMS-B: rt 3.38 min, m/z (positive ion) 346 [M+Na].sup.+.
Intermediate A120: Synthesis of tert-butyl 4-(2-(4-hydroxyphenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate
(303) ##STR00107##
a) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (A118)
(304) A 1 M aqueous solution of sodium dithionite (28.0 mL 28.0 mmol) was added to a stirring suspension of 4-(benzyloxy)benzaldehyde A8 (2.18 g, 10.3 mmol) and tert-butyl 4-(6-amino-5-nitropyridin-2-yl)piperazine-1-carboxylate A 117 (3.02 g, 9.34 mmol) in EtOH (40 mL) at room temperature. The suspension was heated at 70 C. for 6 hours. The suspension was cooled to room temperature and treated with 5 M aqueous ammonium hydroxide (20.0 mL, 100 mmol). The resulting suspension was stirred overnight, filtered, and the solid was washed with water (320 mL) and dried under vacuum to give the title compound (3.40 g, 75%) as a yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.95 (d, J=8.3 Hz, 2H), 7.91-7.84 (m, 1H), 7.49-7.45 (m, 2H), 7.45-7.39 (m, 2H), 7.37 (d, J=7.1 Hz, 1H), 7.08 (d, J=8.9 Hz, 2H), 6.67 (d, J=8.9 Hz, 1H), 5.15 (s, 2H), 3.78-3.29 (m, 8H), 1.51 (s, 9H), NH peak not observed. LCMS-B: rt 3.32 min, m/z (positive ion) 486 [M+H].sup.+.
b) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (A119)
(305) NaH (60% in mineral oil, 448 mg, 11.2 mmol) was added to a stirring solution of tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A118 (3.40 g, 7.00 mmol) in THF (34 mL) and DMF (17 mL) at room temperature under nitrogen. The resulting fine suspension was stirred for 1 hour. SEM-Cl (1.88 g, 11.3 mmol) was added drop-wise and the solution was stirred for 1 hour. A saturated aqueous solution of NaHCO.sub.3 (50 mL) was added and the aqueous layer was extracted with EtOAc (275 mL). The combined organic layers were washed with water (250 mL), brine (50 mL), dried (MgSO.sub.4), filtered and concentrated in vacuo to give a yellow oil which was purified by column chromatography (120 g SiO.sub.2 cartridge, 10-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a pale yellow solid in a 6:1 mixture of regioisomers (4.15 g, 96%). .sup.1H NMR (400 MHz, CDCl.sub.3) Major Isomer: 8.04 (d, J=8.8 Hz, 2H), 7.88 (d, J=8.8 Hz, 1H), 7.49-7.43 (m, 2H), 7.43-7.37 (m, 2H), 7.37-7.30 (m, 1H), 7.10 (d, J=8.8 Hz, 2H), 6.68 (d, J=8.8 Hz, 1H), 5.57 (s, 2H), 5.14 (s, 2H), 3.98-3.75 (m, 2H), 3.68-3.42 (m, 8H), 1.50 (s, 9H), 1.15-0.92 (m, 2H), 0.02 (s, 9H).
c) tert-Butyl 4-(2-(4-hydroxyphenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (A120)
(306) A solution of tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A119 (3.56 g, 5.78 mmol) in EtOH (42 mL) was treated with Pd/C (47% in water, 860 mg). The flask was evacuated of air and purged with nitrogen three times, then evacuated and purged with hydrogen three times. The suspension was stirred under hydrogen for 5 hours, and then filtered through a pad of Celite, eluting with EtOH (220 mL). The filtrate was concentrated in vacuo to give a brown oil which was purified twice by column chromatography (SiO.sub.2 cartridge, 0-10% MeOH in DCM then 10-100% EtOAC in petroleum benzine 40-60 C.). The fractions containing product were combined and concentrated in vacuo to give a brown oil. The resultant material was dissolved in the minimum required volume of DCM, and cyclohexane was added slowly until a precipitate formed. The suspension was concentrated in vacuo to give an off-white solid. The solid was purified twice by recrystallisation from acetonitrile (15 mL/g), to give the title compound as a 14:1 mixture of regioisomers and as a colourless solid (1.20 g, 40%); .sup.1H NMR (400 MHz, CDCl.sub.3) Major Isomer: 10.27 (s, 1H), 7.87 (d, J=8.8 Hz, 1H), 7.83 (d, J=8.7 Hz, 2H), 6.87 (d, J=8.8 Hz, 2H), 6.68 (d, J=8.9 Hz, 1H), 5.55 (s, 2H), 4.09-3.76 (m, 2H), 3.58 (s, 9H), 1.49 (s, 9H), 1.19-0.87 (m, 1H), 0.02 (s, 9H). LCMS-A: rt 6.10 min, m/z (positive ion) 526 [M+H].sup.+.
Example 56-60: Ether Synthesis
(307) ##STR00108##
(308) General Procedure E:
(309) A suspension of tert-butyl 4-(2-(4-hydroxyphenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A120 (105 mg, 0.200 mmol, 1 equiv), aryl bromide (0.220 mmol, 1.1 equiv), and potassium carbonate (36 mg, 0.26 mmol, 1.3 equiv) in acetone (2 mL) was heated at 50 C. for 18 hours. The solvent was removed by a stream of compressed air while heating the suspension at 50 C. DCM (3 mL) and water (1 mL) were added to the resultant residue and the layers were separated using a phase separation cartridge (1 g). The aqueous layer was extracted with DCM (1 mL) and the combined organic layers were concentrated under a stream of compressed air with heating of the solution at 50 C. The residue was cooled to room temperature and dissolved in DCM (1 mL). TFA (0.5 mL) was added and the solution was stirred for 18 hours at room temperature. The solvent was removed by a stream of compressed air and 2 M NaOH aqueous solution was added until the pH>8. The aqueous layer was extracted with EtOAc (320 mL) and the combined organic layers were washed with brine (10 mL) and concentrated by a stream of compressed air. The resultant residue was dissolved in the minimum required volume of MeOH and loaded onto an SCX cartridge (1 g). The cartridge was washed with MeOH (33 mL) and the product was eluted with 2 M ammonia in EtOH (33 mL). The product fractions were concentrated under a stream of air with heating of the solution at 50 C. The residue was centrifuged with MeOH (1 mL) and the solvent was removed by decantation. This was repeated twice and the resulting solid was dried under vacuum to give the title compound as a colourless solid.
(310) TABLE-US-00004 TABLE D Example Product Name and Structure LCMS data Method 56
Example 61: Synthesis of 2-(4-(1-phenylethoxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (61)
(311) ##STR00114##
a) tert-Butyl 4-(2-(4-(1-phenylethoxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (A121)
(312) A solution of tert-butyl 4-(2-(4-hydroxyphenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A120 (0.200 g, 0.380 mmol), (1-bromoethyl)benzene (84 mg, 0.46 mmol) and potassium carbonate (79 mg, 0.57 mmol) in acetonitrile (2 mL) was stirred vigorously at reflux for 17 hours. The suspension was filtered through a phase separation cartridge and the solids were washed with DCM (210 mL). The combined filtrates were concentrated in vacuo. The resulting solid material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a colourless oil (95 mg, 39%). .sup.1H NMR (400 MHz, CDCl.sub.3) 7.97-7.90 (m, 2H), 7.85 (d, J=8.8 Hz, 1H), 7.42-7.30 (m, 4H), 7.30-7.23 (m, 1H), 7.03-6.90 (m, 2H), 6.66 (d, J=8.8 Hz, 1H), 5.53 (s, 2H), 5.39 (q, J=6.4 Hz, 1H), 3.87-3.80 (m, 2H), 3.57 (s, 8H), 1.67 (d, J=6.4 Hz, 3H), 1.49 (s, 9H), 1.12-0.84 (m, 2H), 0.03 (s, 9H).
b) 2-(4-(1-Phenylethoxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (61)
(313) A solution of tert-butyl 4-(2-(4-hydroxyphenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate A121 (9.4 mg, 0.015 mmol) and 1 M TBAF in THF (3 mL) was heated at reflux for 4 hours. The solution was cooled to room temperature and concentrated in vacuo. The crude mixture was taken up in a minimal volume of MeOH and loaded onto a SCX cartridge (1 g). The cartridge was washed with MeOH (33 mL) and the product was eluted with 2 M ammonia in EtOH (33 mL). The product containing fractions were concentrated in vacuo to give a yellow oil. The SCX purification procedure was repeated to give a pale yellow oil which was taken up in 1.25 M HCl in MeOH (1 mL) and heated at 50 C. for 6 hours. The solution was cooled to room temperature and concentrated. The resulting solid was purified by column chromatography (4 g SiO.sub.2, 5-20% (10% Et.sub.3N in MeOH) in DCM). The fractions containing product were combined and concentrated in vacuo to give the title compound as a colourless solid (0.5 mg, 8%). LCMS-A: rt 4.57 min, m/z (positive ion) 400 [M+H].sup.+, m/z (negative ion) 398 [MH].sup..
Example 62: Synthesis of 2-(4-(benzyloxy)-3-bromophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (62)
(314) ##STR00115##
a) tert-Butyl 4-(2-(4-(benzyloxy)-3-bromophenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A122)
(315) A suspension of 4-(benzyloxy)-3-bromobenzaldehyde (0.100 g, 0.343 mmol) and tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (102 mg, 0.349 mmol) were refluxed in MeOH (5 mL) over activated 3 molecular sieves (0.500 g, activated by heat-gun under vacuum) for 22 hours. The resulting suspension was cooled to room temperature, decanted from the molecular sieves and the solvent was removed in vacuo. THF (5 mL) followed by (diacetoxyiodo)benzene (133 mg, 0.412 mmol) were added under an atmosphere of nitrogen and the mixture was stirred at room temperature for 2 hours. The mixture was concentrated in vacuo and then diluted with EtOAc (20 mL) and a saturated aqueous solution of NaHCO.sub.3 (20 mL). The layers were separated and the aqueous layer was extracted with EtOAc (20 mL). The combined organic layers were washed with brine (10 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give a the title compound (71 mg, 36%) as a pale yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 8.47 (d, J=1.9 Hz, 1H), 8.45 (d, J=2.2 Hz, 1H), 8.21 (dd, J=8.6, 2.2 Hz, 1H), 7.97 (d, J=1.9 Hz, 1H), 7.52 (d, J=7.1 Hz, 2H), 7.43 (t, J=7.4 Hz, 2H), 7.39-7.33 (m, 1H), 7.15 (d, J=8.7 Hz, 1H), 5.28 (s, 2H), 4.32 (s, 2H), 2.96-2.81 (m, 3H), 1.95 (d, J=12.8 Hz, 2H), 1.86-1.71 (m, 2H), 1.50 (s, 9H), NH peak not observed. LCMS-A: rt 6.48 min, m/z (positive ion) 563 [M+H].sup.+, m/z (negative ion) 561 [MH].sup..
b) 2-(4-(Benzyloxy)-3-bromophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (62)
(316) A solution of tert-butyl 4-(2-(4-(benzyloxy)-3-bromophenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A122 (12 mg, 0.021 mmol) in TFA (1 mL) and DCM (1 mL) was stirred for 2 hours at room temperature. The volatiles were removed in vacuo and the residue was partitioned between EtOAc (10 mL) and a saturated aqueous solution of NaHCO.sub.3 (5 mL). The aqueous layer was extracted with EtOAc (10 mL). The combined organic layers were washed with brine (5 mL) resulting in a precipitate in the aqueous layer. The aqueous layer was centrifuged for 1 hour and the supernatant was removed. The solid was washed with water (5 mL) and centrifuged for 1 hour. The supernatant was removed and the residue was dried under vacuum for 3 days to give the title compound (5.4 mg, 56%) as an off white solid. .sup.1H NMR (400 MHz, CD.sub.3OD) 8.49 (d, J=2.3 Hz, 1H), 8.47 (d, J=1.9 Hz, 1H), 8.29 (d, J=1.8 Hz, 1H), 8.20 (dd, J=8.7, 2.3 Hz, 1H), 7.54-7.50 (m, 2H), 7.44-7.32 (m, 4H), 5.34 (s, 2H), 3.61-3.54 (m, 2H), 3.28-3.18 (m, 3H), 2.24-2.17 (m, 2H), 2.15-2.04 (m, 2H). LCMS-A: rt 4.76 min, m/z (positive ion) 463 (.sup.79Br), 465 (.sup.81Br) [M+H].sup.+, m/z (negative ion) 461 (.sup.79Br), 463 (.sup.81Br) [MH].sup..
Example 63: Synthesis of 2-(4-(benzyloxy)-3-(1-methyl-1H-pyrazol-4-yl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (63)
(317) ##STR00116##
(318) tert-Butyl 4-(2-(4-(benzyloxy)-3-bromophenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A122 (0.020 g, 0.035 mmol), (1-methyl-1H-pyrazol-4-yl)boronic acid (9.0 mg, 0.043 mmol, 1.3 equiv), PdCl.sub.2(PPh.sub.3).sub.4 (1 mg, 2 mol, 0.05 equiv) and TBAB (1.0 mg, 4.3 mol, 0.1 equiv) were stirred in 1,4-dioxane:water 2:1 (1 mL). Next, K.sub.2CO.sub.3 (12 mg, 0.086 mmol, 2.5 equiv) was added and the reaction mixture was heated under microwave conditions at 90 C. for 45 minutes, 110 C. for 15 minutes and 110 C. for 5 minutes. Water (1 mL) and EtOAc (5 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (5 mL) and the organic layers were combined. The organic layer was washed with brine (5 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give an orange oil. TFA (0.5 mL) and DCM (0.5 mL) were added and the solution was stirred for 30 minutes at room temperature. The volatiles were removed in vacuo to give a brown oil which was purified by column chromatography (4 g SiO.sub.2 cartridge, 10-20% MeOH in DCM then 100% MeOH then 2 M ammonia in MeOH) to give a colourless solid (17.1 mg). The residue was taken up in MeOH (0.5 mL) and loaded onto an SCX cartridge (1 g). The cartridge was washed with MeOH (35 mL) and the product was eluted with 2 M ammonia in EtOH (55 mL). The fractions containing product were concentrated in vacuo to give the title compound (8.0 mg, 36%, purity 75%) as a yellow solid. LCMS-A: rt 4.62 min, m/z (positive ion) 465 [M+H].sup.+.
Example 64: Synthesis of 2-(4-(benzyloxy)-3-(pyridin-3-yl)phenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (64)
(319) ##STR00117##
(320) A suspension of tert-butyl 4-(2-(4-(benzyloxy)-3-bromophenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A122 (56 mg, 0.099 mmol), pyridin-3-ylboronic acid (0.12 mmol), PdCl.sub.2(PPh.sub.3).sub.4 (7.0 mg, 0.010 mmol), TBAB (4.8 mg, 0.015 mmol) and K.sub.2CO.sub.3 (41 mg, 0.30 mmol) in 1,4-dioxane:water 9:1 (1 mL) was irradiated in the microwave at 130 C. for 45 minutes. Water (3 mL) and EtOAc (10 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (10 mL). The organic layers were combined, dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give an orange oil. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-10% MeOH in DCM), the fractions containing product were combined and concentrated in vacuo. TFA (0.5 mL) and DCM (0.5 mL) were added to the residue and the solution was stirred for 30 minutes at room temperature. The volatiles were removed in vacuo and the residue was purified by preparative mass-directed HPLC to give the title compound as a colourless solid (12 mg, 26%). LCMS-B: rt 2.86 min, m/z (positive ion) 462[M+H].sup.+, m/z (negative ion) 460 [MH].sup..
Example 65: Synthesis of 2-(4-(benzyloxy)-3-fluorophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (65))
(321) ##STR00118##
a) 4-(Benzyloxy)-3-fluorobenzaldehyde (A123)
(322) 3-Fluoro-4-hydroxybenzaldehyde (1.00 g, 7.14 mmol), K.sub.2CO.sub.3 (1.48 g, 10.7 mmol), acetonitrile (10 mL) and benzyl bromide (1.02 mL, 8.57 mmol) were stirred vigorously at reflux for 17 hours. The suspension was filtered and the solids were washed with acetonitrile (240 mL). The combined filtrates were concentrated in vacuo and the resulting solid material was recrystallised from cyclohexane to give the title compound as a colourless solid (1.26 g, 77%). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.85 (d, J=2.1 Hz, 1H), 7.66-7.58 (m, 2H), 7.47-7.33 (m, 5H), 7.12 (t, J=8.0 Hz, 1H), 5.24 (s, 2H).
b) 2-(4-(Benzyloxy)-3-fluorophenyl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (65)
(323) A suspension of 4-(benzyloxy)-3-fluorobenzaldehyde A123 (86.6 mg, 0.376 mmol) and tert-butyl 4-(5,6-diaminopyridin-2-yl)piperidine-1-carboxylate A31 (0.100 g, 0.342 mmol) in MeOH (1 mL) over activated 3 molecular sieves (0.100 g, before activation by heat-gun under vacuum) was irradiated in a microwave at 120 C. for 60 minutes. The resulting mixture was cooled to room temperature, decanted from the molecular sieves and the solvent was removed in vacuo. THF (5 mL) followed by (diacetoxyiodo)benzene (132 mg, 0.410 mmol) were added and the mixture was stirred at room temperature for 18 hours. The solvent was removed in vacuo and the residue was partitioned between EtOAc (15 mL) and a solution of 10% wt/v aqueous NaHCO.sub.3 (10 mL). The layers were separated and the aqueous layer was extracted with EtOAc (15 mL). The organic layers were combined, washed with brine (10 mL) and concentrated in vacuo. The crude material was purified using column chromatography (12 g SiO.sub.2 cartridge, 0-20% MeOH in DCM), the fractions containing the product were combined and concentrated in vacuo to give the desired intermediate as a pale yellow oil. The material was treated with DCM (3 mL) and TFA (1 mL) and stirred for 10 minutes. The solvent was removed in vacuo and the material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-20% MeOH) to give the title compound as a colourless solid (65 mg, 47%). .sup.1H NMR (400 MHz, CD.sub.3OD) 8.32 (d, J=2.0 Hz, 1H), 7.97-7.87 (m, 3H), 7.53-7.45 (m, 2H), 7.43-7.38 (m, 2H), 7.37-7.32 (m, 2H), 5.28 (s, 2H), 3.59-3.51 (m, 2H), 3.25-3.10 (m, 3H), 2.21-2.14 (m, 2H), 2.08-1.95 (m, 2H). LCMS-A: rt 4.73 min, m/z (positive ion) 403 [M+H].sup.+.
Example 66: Synthesis of methyl 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoate dihydrogen chloride salt (66)
(324) ##STR00119##
a) Methyl 2-(benzyloxy)-5-formylbenzoate (A124)
(325) Methyl 5-formylsalicylate (5.00 g, 27.8 mmol), potassium carbonate (5.26 g, 41.7 mmol), acetonitrile (50 mL) and benzyl bromide (4.0 mL, 34 mmol) were combined and stirred vigorously at reflux for 17 hours. Further portions of benzyl bromide (4 mL, 34 mL) and potassium carbonate (5.26 g, 41.7 mmol) were added and the mixture was refluxed for 2 days. The suspension was filtered and the solids washed with acetonitrile (240 mL). The combined filtrates were concentrated in vacuo and the resulting oil was purified by column chromatography (120 g SiO.sub.2 cartridge, 0-80% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a colourless oil (3.85 g, 51%). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.92 (d, J=0.5 Hz, 1H), 8.36 (d, J=2.2 Hz, 1H), 7.98 (dd, J=8.7, 2.2 Hz, 1H), 7.51-7.47 (m, 2H), 7.44-7.37 (m, 2H), 7.37-7.30 (m, 1H), 7.14 (d, J=8.7 Hz, 1H), 5.30 (s, 2H), 3.94 (s, 3H). LCMS-B: rt 3.44 min, m/z (positive ion) 293 [M+Na].sup.+, m/z (negative ion) 269 [MH].sup..
b) tert-Butyl 4-(2-(4-(benzyloxy)-3-(methoxycarbonyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A125)
(326) A suspension of methyl 2-(benzyloxy)-5-formylbenzoate A 124 (0.270 g, 1.00 mmol) and tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A31 (292 mg, 1.00 mmol) in MeOH (3 mL) over activated 3 molecular sieves (0.100 g, before activation by heat-gun under vacuum) was irradiated in a microwave at 120 C. for 2 hours. The resulting mixture was cooled to room temperature, decanted from the molecular sieves and the solvent was removed in vacuo. THF (3 mL) followed by (diacetoxyiodo)benzene (387 mg, 1.20 mmol) were added and the mixture was stirred at room temperature for 14 hours. The solvent was removed in vacuo and the residue was partitioned between DCM (25 mL) and a saturated aqueous solution of NaHCO.sub.3 (25 mL). The layers were separated and the aqueous layer was extracted with DCM (25 mL). The organic layers were combined, washed with brine (25 mL) and concentrated in vacuo. The crude material was purified using column chromatography (12 g SiO.sub.2 cartridge, 50-100% EtOAc in petroleum benzine 40-60 C. then 0-20% MeOH in EtOAc), the fractions containing the product were combined and concentrated in vacuo to give the desired intermediate as an orange oil. The orange solid was taken up in MeOH (1 mL) and centrifuged for 10 minutes. The supernatant was removed and the solid was centrifuged in a further portion of MeOH (1 mL) for 10 minutes. The supernatant was removed and the solid was dried under vacuum to give the title compound as an off-white solid (109 mg, 19%). LCMS-A: rt 3.47 min, m/z (positive ion) 543 [M+H].sup.+.
c) Methyl 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoate dihydrogen chloride salt (66)
(327) A solution of tert-butyl 4-(2-(4-(benzyloxy)-3-(methoxycarbonyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A125 (10.1 mg, 0.0186 mmol) in 1.25 M HCl in MeOH (1.00 mL, 1.25 mmol) was heated at 55 C. for 3 hours. The reaction mixture was cooled to room temperature and concentrated in vacuo to give the title compound a colourless solid (8.6 mg, 90%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 9.15-8.88 (m, 2H), 8.66 (d, J=2.3 Hz, 1H), 8.48 (dd, J=8.9, 2.4 Hz, 1H), 8.39 (d, J=1.9 Hz, 1H), 8.06 (s, 1H), 7.56-7.48 (m, 3H), 7.43 (t, J=7.4 Hz, 2H), 7.34 (t, J=7.2 Hz, 1H), 5.37 (s, 2H), 3.89 (s, 3H), 5H obscured by water peak, 2.08-1.97 (m, 4H). LCMS-A: rt 4.63 min, m/z (positive ion) 443 [M+H].sup.+; m/z (negative ion) 441 [MH].sup..
Example 67: Synthesis of 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid dihydrochloride salt (67)
(328) ##STR00120##
a) 2-(Benzyloxy)-5-(6-(1-(tert-butoxycarbonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid hydrogen chloride salt (A126)
(329) A suspension of tert-butyl 4-(2-(4-(benzyloxy)-3-(methoxycarbonyl)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A125 (0.100 g, 0.184 mmol), 1 M aqueous NaOH (1.0 mL, 1.0 mmol) and MeOH (1 mL) was heated at 85 C. for 3 hours. The resulting solution was cooled to room temperature and the volatiles were removed in vacuo. The solution was diluted with water (10 mL), extracted with DCM (210 mL) and the organic layer was discarded. The aqueous layer was acidified with 6 M HCl (1 mL) and the resulting suspension was filtered, washed with water (25 mL) and air dried to give the title compound as a colourless powder. The filtrate was extracted with EtOAc:MeOH (6:1, 235 mL). The organic layers were combined, washed with brine (30 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. Toluene (3 mL) was added and concentrated in vacuo to give the title compound as a colourless powder (Combined total 101 mg, 95%) LCMS-B: rt 3.29 min, m/z (positive ion) 529 [M+H].sup.+.
b) 2-(Benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid dihydrochloride salt (67)
(330) A suspension of 2-(benzyloxy)-5-(6-(1-(tert-butoxycarbonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid A126 (7.0 mg, 0.012 mmol) and 4 M HCl in 1,4-dioxane (1 mL, 4 mmol) were stirred at 55 C. for 4 hours. The reaction mixture was concentrated in vacuo to give the title compound as a colourless solid (6.0 mg, 97%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.89-8.78 (m, 1H), 8.70 (d, J=9.5 Hz, 1H), 8.59 (d, J=2.4 Hz, 1H), 7.95 (dd, J=8.8, 2.4 Hz, 1H), 8.36-8.30 (m, 1H), 7.95 (br s, 1H), 7.59-7.50 (m, 2H), 7.50-7.38 (m, 3H), 7.35 (t, J=7.3 Hz, 1H), 5.35 (s, 2H), 3.16-2.87 (m, 4H), 2.19-1.85 (m, 4H), 2NH peaks not observed. LCMS-B: rt 2.95 min, m/z (positive ion) 429 [M+H].sup.+.
Example 68: Synthesis of 2-(benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzamide dihydrogen chloride salt (68)
(331) ##STR00121##
a) tert-Butyl 4-(2-(4-(benzyloxy)-3-carbamoylphenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A128
(332) SOCl.sub.2 (13 L, 0.18 mmol) was added to a suspension of 2-(benzyloxy)-5-(6-(1-(tert-butoxycarbonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzoic acid A127 (63.0 mg, 0.119 mmol) and DMF (2 drops) in DCM (1.6 mL) under N.sub.2 at room temperature. Further portions of SOCl.sub.2 (52 L, 0.72 mmol) and DMF (1 mL) were added and the resultant solution was stirred for 30 minutes before a 28-30% ammonium hydroxide solution (1 mL) was added. The reaction mixture was stirred for 1 hour, concentrated in vacuo and the residue partitioned between water (10 mL) and EtOAc (20 mL). A precipitate formed and was isolated by filtration to give a crop of title compound as a colourless solid. The filtrate layers were separated and the aqueous layer was extracted with EtOAc (20 mL). The organic layers were combined, washed with 1 M aqueous NaOH (15 mL), water (15 mL), brine (15 mL) dried (MgSO.sub.4), filtered and concentrated in vacuo. The crude product was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-10% MeOH in DCM) the fractions containing product were combined and concentrated in vacuo to give a second crop of the title compound as a colourless solid (Combined total 29.0 mg, 46%). LCMS-B: 3.31 min, m/z (positive ion) 528 [M+H].sup.+, m/z (negative ion) 526 [MH].sup..
b) 2-(Benzyloxy)-5-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)benzamide dihydrogen chloride salt (68)
(333) A suspension of tert-butyl 4-(2-(4-(benzyloxy)-3-carbamoylphenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A128 (7.7 mg, 0.015 mmol) and 1.25 M HCl in MeOH (1 mL, 1.25 M) was heated at 55 C. for 4 hours. The reaction mixture was concentrated in vacuo to give the title compound as a colourless solid (6.7 mg, 83%). LCMS-B: rt 2.87 min, m/z (positive ion) 428 [M+H].sup.+.
Example 69: Synthesis of 2-(4-(benzyloxy)-3-(1-methyl-1H-pyrazol-4-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (69)
(334) ##STR00122##
a) 6-(4-(Ethylsulfonyl)piperazin-1-yl)-3-nitropyridin-2-amine (A129)
(335) A solution of 6-chloro-3-nitropyridin-2-amine (2.50 g, 14.4 mmol), 1-(ethylsulfonyl)piperazine (3.08 g, 17.3 mmol) and DIPEA (5.02 mL, 28.8 mmol) in DMF (25 mL) was heated at 85 C. for 1 hour. The yellow solution was treated with water (50 mL) and cooled to room temperature. The suspension was filtered and the solid air dried to give the title compound (4.29 g, 95%) as a bright yellow solid. LCMS-A: rt 5.64 min, m/z (positive ion) 316 [M+H].sup.+.
b) 6-(4-(Ethylsulfonyl)piperazin-1-yl)pyridine-2,3-diamine (A130)
(336) A suspension of tert-butyl 4-(6-amino-5-nitropyridin-2-yl)piperazine-1-carboxylate A129 (2.06 g, 6.53 mmol) and 10% Pd/C (47% water wet, 400 mg) in EtOH (50 mL) was stirred at 50 C. under an atmosphere of hydrogen for 17 hours. The suspension was filtered through Celite and the filtrate was concentrated in vacuo to give the title compound (1.84 g, 99%) as a brown/purple crystalline solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 6.70 (d, J=8.0 Hz, 1H), 5.85 (d, J=8.1 Hz, 1H), 5.16 (s, 2H), 4.03 (br, s, 2H), 3.27-3.15 (m, 8H), 3.04 (q, J=7.3 Hz, 2H), 1.20 (t, J=7.4 Hz, 3H). LCMS-B: rt 2.60 min, m/z (positive ion) 286 [M+H].sup.+.
c) 2-(4-(Benzyloxy)-3-bromophenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (A131)
(337) A suspension of 4-(benzylaoxy)-3-bromobenzaldehyde (1.12 g, 3.86 mmol) and 6-(4-(ethylsulfonyl)piperazin-1-yl)pyridine-2,3-diamine A130 (1.00 g, 3.50 mmol) in MeOH (30 mL) over activated 3 molecular sieves (0.500 g, before activation by heat-gun under vacuum) was irradiated in a microwave at 130 C. for 260 minutes, then 140 C. for 15 minutes. The resulting suspension was cooled to room temperature, decanted from the molecular sieves and the solvent was removed in vacuo. THF (50 mL) followed by (diacetoxyiodo)benzene (1.35 g, 4.21 mmol) were added and the mixture was stirred at room temperature for 24 hours. The mixture was concentrated in vacuo and diluted with MeOH (5 mL). The solution was loaded onto an SCX cartridge (10 g) and washed with MeOH (420 mL). The product was eluted with 2 M NH.sub.3 in EtOH (350 mL) and the fractions containing product were concentrated in vacuo. The crude material was purified by column chromatography twice ((12 g SiO.sub.2 cartridge, 0-10% MeOH in DCM) then (12 g SiO.sub.2 cartridge, 0-10% MeOH in EtOAc), to give the title compound (789 mg, 40%) as a brown solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.34 (d, J=2.2 Hz, 1H), 8.06 (dd, J=8.6, 2.2 Hz, 1H), 7.89-7.73 (m, 1H), 7.51-7.46 (m, 2H), 7.44-7.39 (m, 2H), 7.34 (t, J=8.0 Hz, 2H), 6.83 (d, J=8.9 Hz, 1H), 5.27 (s, 2H), 3.58 (s, 4H), 3.30 (d, J=5.1 Hz, 4H), 3.07 (q, J=7.4 Hz, 2H), 1.22 (t, J=7.4 Hz, 3H), NH peak not observed. LCMS-A: rt 3.73 min, m/z (positive ion) 566 (.sup.79Br), 568 (.sup.81Br) [M+H].sup.+, m/z (negative ion) 564 (.sup.79Br), 566 (.sup.81Br) [MH].sup..
d) 2-(4-(Benzyloxy)-3-(1-methyl-1H-pyrazol-4-yl)phenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (69)
(338) To a stirred suspension of 2-(4-(benzyloxy)-3-bromophenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine A131 (0.050 g, 0.090 mmol), (1-methyl-1H-pyrazol-4-yl)boronic acid (40.0 mg, 0.192 mmol), PdCl.sub.2(PPh.sub.3).sub.4 (0.010 g, 0.015 mmol) and TBAB (8.4 mg, 0.026 mmol, 0.29 equiv) in 1,4-dioxane:water 9:1 (1 mL) was added K.sub.2CO.sub.3 (37 mg, 0.27 mmol) and the reaction mixture was irradiated in the microwave at 110 C. for 15 minutes. Water (1 mL) and EtOAc (5 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (5 mL) and the organic layers were combined. The organic layers were washed with brine (5 mL), dried (Na.sub.2SO.sub.4), filtered, and concentrated in vacuo to give an orange oil that was purified by two iterations of column chromatography (4 g SiO.sub.2 cartridge, 0-10% MeOH in DCM, then 12 g SiO.sub.2 cartridge, 0-10% MeOH in DCM) to give a pale yellow solid. The material was suspended in MeOH (3 mL), sonicated for 5 min and centrifuged for 10 minutes. The supernatant was removed and the solid washed with MeOH (1 mL). The suspension was centrifuged again for 10 minutes and the supernatant was removed. The solid was dried under vacuum to give the title compound (13.0 mg, 26%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.38 (d, J=2.3 Hz, 1H), 8.16 (s, 1H), 7.96 (d, J=0.8 Hz, 1H), 7.94 (dd, J=8.8, 2.3 Hz, 1H), 7.82 (d, J=8.5 Hz, 1H), 7.57-7.49 (m, 2H), 7.47-7.40 (m, 2H), 7.39-7.32 (m, 1H), 7.27 (d, J=8.6 Hz, 1H), 6.83 (d, J=8.9 Hz, 1H), 5.32 (s, 2H), 3.87 (s, 3H), 3.66-6.58 (m, 4H), 3.33-3.28 (m, 4H), 3.10 (q, J=7.4 Hz, 2H), 1.23 (t, J=7.4 Hz, 3H). LCMS-A: rt 5.12 min, m/z (positive ion) 558 [M+H].sup.+.
Example 70-73: General Addition of Heterocycles by Suzuki Coupling
(339) ##STR00123##
(340) General Procedure F:
(341) To a stirred suspension of 2-(4-(benzyloxy)-3-bromophenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine A131 (51 mg, 0.090 mmol), the desired boronic acid (0.11 mmol, 1.1 equiv), PdCl.sub.2(PPh.sub.3).sub.2 (7 mg, 0.009 mmol, 0.1 equiv) and TBAB (6 mg, 0.009 mmol, 0.1 equiv) in 1,4-dioxane:water (3:1, 1 mL) was added K.sub.2CO.sub.3 (38 mg, 0.27 mmol, 3 equiv). The reaction mixture was irradiated in the microwave at 130 C. for 45 minutes. Water (3 mL) and EtOAc (10 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (10 mL). The organic layers were combined and dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-10% MeOH in DCM) and the fractions containing product were combined and concentrated in vacuo to give the title compound.
(342) TABLE-US-00005 TABLE E Boronic Example acid Product Name and Structure LCMS data Method 70
Example 74: Synthesis of 2-(4-(benzyloxy)-3-methylphenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (74)
(343) ##STR00132##
(344) A suspension of 2-(4-(benzyloxy)-3-bromophenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine A131 (55.7 mg, 0.100 mmol), DABAL-AIMe.sub.3 (26.9 mg, 0.105 mmol), Pd.sub.2dba.sub.3 (8.6 mg, 0.015 mmol) and X-Phos (14 mg, 0.030 mmol) in THF (0.8 mL) was degassed with nitrogen before heating in a microwave for 15 minutes at 120 C. An aqueous solution of HCl (1 M, 1 mL) was added and the mixture was extracted with EtOAc (35 mL). The aqueous layer was adjusted to pH 5 with aqueous NaOH (2 M) and then extracted with DCM (320 mL). The combined organic layers were washed with brine (10 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 80%-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (22 mg, 45%). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.77 (s, 1H), 7.89 (d, J=8.7 Hz, 1H), 7.83 (s, 1H), 7.71 (d, J=8.3 Hz, 1H), 7.48-7.44 (m, 2H), 7.44-7.37 (m, 2H), 7.37-7.30 (m, 1H), 6.97 (d, J=8.5 Hz, 1H), 6.66 (d, J=8.8 Hz, 1H), 5.15 (s, 2H), 3.66 (t, J=5.0 Hz, 4H), 3.41 (t, J=5.0 Hz, 4H), 2.97 (q, J=7.4 Hz, 2H), 2.34 (s, 3H), 1.39 (t, J=7.4 Hz, 3H). LCMS-B: rt 3.40 min, m/z (positive ion) 492 [M+H].sup.+; m/z (negative ion) 490 [MH].sup..
Example 75: Synthesis of 2-(4-(benzyloxy)-3-methoxyphenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (75)
(345) ##STR00133##
(346) A 25% sodium methoxide solution in MeOH was prepared by adding freshly cut sodium (430 mg) portion-wise into anhydrous MeOH (4 mL) under a nitrogen atmosphere at room temperature. The 25% sodium methoxide solution (0.200 mL, 0.952 mmol) was added to a stirring suspension of 2-(4-(benzyloxy)-3-bromophenyl)-5-(4-(ethylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine A131 (0.050 g, 0.090 mmol), CuCl (8.9 mg, 0.090 mmol), DMF (500 L) and MeOH (250 L) in a tube at room temperature under N.sub.2. The tube was sealed and heated at 120 C. for 17 hours. The reaction mixture was cooled to room temperature and partitioned between EtOAc (5 mL) and a saturated aqueous solution of NH.sub.4Cl (5 mL). The layers were separated and the aqueous layer was extracted with EtOAc (25 mL). The combined organic layers were washed with water (10 mL), brine (10 mL) and a saturated aqueous solution of NH.sub.4Cl (10 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 80-100% EtOAc in petroleum benzine 40-60 C. then 0-10% MeOH in EtOAc) to give the title compound as a pale yellow solid (6.4 mg, 14%). .sup.1H NMR (400 MHz, CD.sub.3OD) 7.96-7.52 (m, 3H), 7.52-7.43 (m, 2H), 7.41-7.35 (m, 2H), 7.35-7.28 (m, 1H), 7.09 (s, 1H), 6.84 (d, J=7.6 Hz, 1H), 5.17 (s, 2H), 3.94 (s, 3H), 3.66 (t, J=4.7 Hz, 4H), 3.38 (t, J=4.5 Hz, 4H), 3.06 (q, J=7.4 Hz, 2H), 1.34 (t, J=7.4 Hz, 3H). LCMS-B: rt 3.26 min, m/z (positive ion) 508 [M+H].sup.+, m/z (negative ion) 506 [MH].sup..
Example 76: Synthesis of ethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetate (76)
(347) ##STR00134##
a) Diethyl 2-(2-amino-3-nitropyridin-4-yl)malonate (A132)
(348) NaH (60% dispersion in mineral oil, 0.830 g, 20.7 mmol) was added to a solution of diethyl malonate (3.16 mL, 20.7 mmol) in NMP (50 mL) and the resulting solution was stirred at room temperature for 10 minutes. 4-Chloro-3-nitropyridin-2-amine A14 (1.00 g, 5.76 mmol) was then added and the mixture heated at 50 C. for 2 hours. The mixture was cooled to room temperature and diluted with EtOAc (250 mL) and water (100 mL). The organic layer was separated and washed with water (100 mL) followed by brine (100 mL). This process was repeated three times before the organic layer was dried (Na.sub.2SO.sub.4), filtered and the filtrate concentrated under reduced pressure to give a yellow oil which was purified by silica gel column chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a yellow solid (1.69 g, 99%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.28 (d, J=4.9 Hz, 1H), 7.53 (s, 2H), 6.58 (d, J=5.0 Hz, 1H), 5.20 (s, 1H), 4.18 (qd, J=7.1, 0.9 Hz, 4H), 1.18 (t, J=7.1 Hz, 6H). LCMS-B: rt 3.20 min, m/z (positive ion) 298 [M+H].sup.+.
b) Ethyl 2-(2-amino-3-nitropyridin-4-yl)acetate (A133)
(349) LiCl (0.719 g, 17.0 mmol) was added to a suspension of diethyl 2-(2-amino-3-nitropyridin-4-yl)malonate A132 (1.68 g, 5.65 mmol) in DMSO (25 mL) and water (25 mL). The mixture was heated at 130 C. for 18 hours before being cooled to room temperature and diluted with EtOAc (250 mL) and water (200 mL). The organic layer was separated and washed with water (100 mL), brine (100 mL), dried (sodium sulfate), filtered and the volatiles removed in vacuo to give a yellow semi-solid which was purified by silica gel column chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a yellow solid (1.10 g, 86%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.20 (d, J=4.7 Hz, 1H), 7.45 (s, 2H), 6.67 (d, J=4.7 Hz, 1H), 4.08 (q, J=7.1 Hz, 2H), 3.92 (s, 2H), 1.17 (t, J=7.1 Hz, 3H). LCMS-B: rt 3.05 min, m/z (positive ion) 226 [M+H].sup.+.
c) Ethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetate (76)
(350) A freshly prepared aqueous solution of sodium dithionite (1.00 M, 3.33 mL, 3.33 mmol) was added to a suspension of 4-(benzyloxy)benzaldehyde A8 (0.259 g, 1.22 mmol) and ethyl 2-(2-amino-3-nitropyridin-4-yl)acetate A133 (0.250 g, 1.11 mmol) in EtOH (7 mL). The resulting yellow suspension was heated under microwave irradiation at 110 C. for 15 minutes. The mixture was cooled to room temperature, an aqueous solution of NH.sub.4OH (5 M, 2 mL) was added and the reaction mixture was stirred for 5 minutes at room temperature. The resulting mixture was filtered, and the solid was washed with water (10 mL) and air dried to give the title compound as a cream solid (0.054 g, 13%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.11 (s, 1H), 8.22 (s, 1H), 8.17 (d, J=8.8 Hz, 2H), 7.49 (d, J=7.1 Hz, 2H), 7.45-7.39 (m, 2H), 7.38-7.32 (m, 1H), 7.21 (d, J=8.4 Hz, 2H), 7.13 (d, J=3.9 Hz, 1H), 5.21 (s, 2H), 4.13 (q, J=7.1 Hz, 2H), 4.07 (s, 2H), 1.20 (t, J=7.1 Hz, 3H). LCMS-B: rt 3.27 min, m/z (positive ion) 388 [M+H].sup.+.
Example 77: Synthesis of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetic acid (77)
(351) ##STR00135##
(352) LiOHH.sub.2O (0.019 g, 0.45 mmol) was added to a mixture of ethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetate 76 (0.035 g, 0.090 mmol) in MeOH (1 mL), THF (3 mL) and water (1 mL). The resulting mixture was stirred for 5 hours at room temperature before the volatiles were removed in vacuo. The residue was taken up in EtOAc (25 mL) and 2 M aqueous NaOH (25 mL) and the layers separated. The aqueous layer was acidified with 2 M aqueous HCl to pH 1 and then EtOAc (25 mL) was added. A solid precipitate which was insoluble in both the aqueous and organic phases was isolated by filtration, washed with water (15 mL) and allowed to air dry for 18 hours to give the title compound as a white solid (16 mg, 49%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.49 (d, J=4.7 Hz, 1H), 8.33 (d, J=8.5 Hz, 2H), 7.53-7.47 (m, 3H), 7.43 (t, J=7.3 Hz, 2H), 7.40-7.34 (m, 1H), 7.32 (d, J=8.9 Hz, 2H), 5.26 (s, 2H), 4.27 (s, 2H). LCMS-B: rt 3.07 min, m/z (positive ion) 360 [M+H].sup.+.
Example 78: Synthesis of 2-(4-(benzyloxy)phenyl)-7-methyl-3H-imidazo[4,5-b]pyridine (78)
(353) ##STR00136##
(354) To a suspension of 4-(benzyloxy)benzaldehyde A8 (0.076 g, 0.36 mmol) and 4-methyl-3-nitropyridin-2-amine A17 (0.050 g, 0.33 mmol) in EtOH (2.0 mL) was added an aqueous solution of sodium dithionite (1.00 M, 0.980 mL, 0.980 mmol). The resulting yellow suspension was irradiated in a microwave reactor at 110 C. for 15 min. The mixture was cooled to room temperature and a 28% w/w aqueous solution of NH.sub.4OH (1 mL) was added. The mixture was stirred for 5 minutes and then filtered to give a yellow solid. The crude material was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.014 g, 14%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.16 (br s, 1H), 8.18 (d, J=8.8 Hz, 2H), 8.14 (d, J=4.9 Hz, 1H), 7.52-7.47 (m, 2H), 7.46-7.38 (m, 2H), 7.39-7.31 (m, 1H), 7.20 (d, J=9.0 Hz, 2H), 7.02 (d, J=4.9 Hz, 1H), 5.21 (s, 2H), 2.58 (s, 3H). LCMS-B: rt 3.09 min, m/z (positive ion) 316.2 [M+H].sup.+.
Example 79: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-ylmethyl)-3H-imidazo[4,5-b]pyridine (79)
(355) ##STR00137##
a) tert-Butyl 4-((2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methy)-3H-imidazo[4,5-b]pyridin-5-yl)methyl)piperazine-1-carboxylate (A134)
(356) In a microwave tube, 2-(4-(benzyloxy)phenyl)-5-chloro-3-((2-(trimethylsilyl) ethoxy)methyl)-3H-imidazo[4,5-b]pyridine A52 (0.032 g, 0.069 mmol), Pd(OAc).sub.2 (0.001 g, 0.003 mmol), XPhos (0.003 g, 0.007 mmol), Cs.sub.2CO.sub.3 (0.067 g, 0.21 mmol) and potassium (4-tert-butoxycarbonylpiperazin-1-yl)methyltrifluoroborate (0.022, 0.072 mmol) were suspended in THF:H.sub.2O (10:1, 1 mL). The mixture was irradiated in a microwave at 110 C. for 12 hours, cooled and then concentrated to dryness. The crude material was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH in EtOAc) to give the title compound (0.025 g, 58%) as a pale yellow solid. .sup.1H NMR (400 MHz, d-Acetone) 8.17-8.10 (m, 2H), 7.98 (d, J=8.1 Hz, 1H), 7.60-7.49 (m, 2H), 7.47 (d, J=8.2 Hz, 1H), 7.45-7.38 (m, 2H), 7.39-7.31 (m, 1H), 7.24-7.18 (m, 2H), 5.72 (s, 2H), 5.25 (s, 2H), 3.97-3.80 (m, 2H), 3.78 (s, 2H), 3.47-3.36 (m, 4H), 2.56-2.41 (m, 4H), 1.43 (s, 9H), 1.07-0.97 (m, 2H), 0.02 (s, 9H). LCMS-A: rt 5.61 min, m/z (positive ion) 630.3 [M+H].sup.+.
b) 2-(4-(Benzyloxy)phenyl)-5-(piperazin-1-ylmethyl)-3H-imidazo[4,5-b]pyridine (79)
(357) tert-Butyl-4-((2-(4-(benzyloxy)phenyl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-5-yl)methyl)piperazine-1-carboxylate A134 (0.020 g, 0.032 mmol) was dissolved in DCM (2 mL) under an atmosphere of nitrogen. TFA (1 mL) was added and the mixture was stirred at room temperature for 17 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (20 mL) and aqueous NaOH (2 M, 20 mL). The layers were separated and the aqueous phase was extracted with EtOAc (20 mL). The combined organics were washed with brine (20 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.013 g, 98%) as an off-white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 7.95 (d, J=8.4 Hz, 1H), 7.91-7.85 (m, 2H), 7.42-7.23 (m, 5H), 7.19-7.15 (m, 1H), 7.04 (d, J=8.1 Hz, 2H), 5.08 (s, 2H), 3.66 (s, 2H), 2.97 (br s, 4H), 2.51 (br s, 4H). LCMS-A: rt 4.50 min, m/z (positive ion) 400.2 [M+H].sup.+.
Example 80: Synthesis of ethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetate (80)
(358) ##STR00138##
a) Diethyl 2-(6-amino-5-nitropyridin-2-yl)malonate (A135)
(359) NaH (60% dispersion in mineral oil, 0.830 g, 20.7 mmol) was added to a solution of diethyl malonate (3.16 mL, 20.7 mmol) in NMP (50 mL) and the resulting solution stirred at room temperature for 10 minutes. After this time, 6-chloro-3-nitropyridin-2-amine A44 (1.00 g, 5.76 mmol) was added and the mixture heated at 50 C. for 2 hours. The mixture was cooled to room temperature and diluted with EtOAc (250 mL) and water (100 mL). The organic layer was separated and washed sequentially with water (100 mL) followed by brine (100 mL). This process was repeated three times before the organic layer was dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a red oil. The crude material was purified by silica gel chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (1.49 g, 70%) as an orange solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.41 (d, J=8.5 Hz, 1H), 7.94 (br s, 2H), 6.76 (d, J=8.6 Hz, 1H), 5.03 (s, 1H), 4.17 (qd, J=7.1, 5.8 Hz, 4H), 1.20 (dt, J=14.1, 7.1, 7.1 Hz, 6H). LCMS-A: rt 6.20 min, m/z (positive ion) 298.1 [M+H].sup.+.
b) Ethyl 2-(6-amino-5-nitropyridin-2-yl)acetate (A136)
(360) To a suspension of diethyl 2-(6-amino-5-nitropyridin-2-yl)malonate A135 (1.19 g, 4.03 mmol) in DMSO (25 mL) and water (25 mL) was added LiCl (0.513 g, 12.1 mmol) and the resulting mixture was heated at 130 C. for 18 hours. After cooling to room temperature the mixture was diluted with EtOAc (250 mL) and water (200 mL). The organic layer was separated and washed with water (100 mL), brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a yellow semi-solid. This material was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.350 g, 39%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.35 (d, J=8.5 Hz, 1H), 7.92 (brs, 2H), 6.72 (d, J=8.5 Hz, 1H), 4.10 (q, J=7.1, 7.1 Hz, 2H), 3.76 (s, 2H), 1.18 (t, J=7.1 Hz, 3H). LCMS-A: rt 5.79 min, m/z (positive ion) 226.1 [M+H].sup.+.
c) Ethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetate (80)
(361) To a suspension of 4-(benzyloxy)benzaldehyde A8 (0.209 g, 0.987 mmol) and ethyl 2-(6-amino-5-nitropyridin-2-yl)acetate A136 (0.202 g, 0.897 mmol) in EtOH (6 mL) was added an aqueous solution of sodium dithionite solution (1.00 M, 2.69 mL, 2.69 mmol). The resulting yellow suspension was heated at 70 C. and stirred for 17 hours. After cooling to room temperature, 28% w/w aqueous solution of NH.sub.4OH (4 mL) was added and the mixture was stirred for a further 5 minutes. The mixture was concentrated in vacuo and the crude material was purified by silica gel chromatography (40 g SiO.sub.2 cartridge, 20-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.072 g, 21%) as a yellow solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 12.51 (br s, 1H), 7.94 (d, J=8.3 Hz, 2H), 7.82-7.64 (m, 1H), 7.36-7.26 (m, 3H), 7.26-7.17 (m, 2H), 7.03-6.89 (m, 1H), 6.81 (d, J=8.4 Hz, 2H), 4.91 (s, 2H), 3.96 (q, J=7.1 Hz, 2H), 3.74 (s, 2H), 1.04 (t, J=7.1 Hz, 3H). LCMS-B: rt 3.28 min, m/z (positive ion) 388.2 [M+H].sup.+.
Example 81: Synthesis of ethyl 2-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetate (81)
(362) ##STR00139##
Ethyl 2-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetate (81)
(363) To a suspension of 4-(phenoxymethyl)benzaldehyde A20 (0.104 g, 0.488 mmol) and (6-amino-5-nitropyridin-2-yl)methyl propionate A136 (0.100 g, 0.444 mmol) in EtOH (4 mL) was added an aqueous solution of sodium dithionite (1.00 M, 1.33 mL, 1.33 mmol). The resulting yellow suspension was irradiated in a microwave at 110 C. for 15 minutes. The mixture was cooled to room temperature, a 28% w/w aqueous solution of NH.sub.4OH (2 mL) was added and the mixture was stirred for 5 minutes. The suspension was filtered to give a yellow solid that was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.020 g, 12%) as a pale yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.22 (d, J=8.3 Hz, 2H), 8.05-7.97 (m, 1H), 7.70-7.56 (m, 2H), 7.37-7.26 (m, 2H), 7.22 (d, J=8.2 Hz, 1H), 7.04 (d, J=7.8 Hz, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.20 (s, 2H), 4.10 (q, J=7.1 Hz, 2H), 3.92 (s, 2H), 1.19 (t, J=7.1 Hz, 3H). LCMS-A: rt 6.00 min, m/z (positive ion) 388.2 [M+H].sup.+.
Example 82: Synthesis of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetic acid (82)
(364) ##STR00140##
a) Diethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)malonate (A137)
(365) To a suspension of 4-(benzyloxy)benzaldehyde A8 (0.196 g, 0.925 mmol) and diethyl 2-(6-amino-5-nitropyridin-2-yl)malonate A135 (0.250 g, 0.841 mmol) in EtOH (6 mL) was added an aqueous solution of sodium dithionite (1.00 M, 2.52 mL, 2.52 mmol). The resulting yellow suspension was irradiated in a microwave at 110 C. for 30 minutes. The mixture was cooled to room temperature, a 28% w/w aqueous solution of NH.sub.4OH (4 mL) was added and the reaction mixture was stirred for 5 minutes. The mixture was concentrated in vacuo and the crude material was purified by silica gel chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH in EtOAc) to give the title compound (0.050 g, 13%) as a yellow semi-solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 10.57 (br s, 1H), 7.96 (d, J=8.9 Hz, 2H), 7.47-7.28 (m, 7H), 7.08-6.96 (m, 2H), 5.09 (s, 2H), 5.00 (s, 1H), 4.25 (qd, J=7.1, 5.9 Hz, 4H), 1.26 (t, J=7.1 Hz, 6H). LCMS-A: rt 6.29 min, m/z (positive ion) 460.2 [M+H].sup.+.
b) 2-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)acetic acid (82)
(366) To a solution of diethyl 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)malonate A137 (0.040 g, 0.087 mmol) in EtOH (2 mL) was added aqueous NaOH (2 M, 2 mL). This mixture was heated at 100 C. for 1 hour and then cooled to room temperature. The volatiles were removed in vacuo and the remaining mixture was acidified with aqueous HCl (2 M, 3 mL) and extracted with DCM (310 mL). The organics were combined, dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.020 g, 64%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 12.40 (s, 1H), 8.16 (d, J=8.8 Hz, 2H), 8.01 (d, J=8.1 Hz, 1H), 7.51-7.45 (m, 2H), 7.45-7.39 (m, 2H), 7.38-7.31 (m, 1H), 7.29-7.18 (m, 3H), 5.23 (s, 2H), 3.86 (s, 2H), OH proton not observed LCMS-B: rt 3.12 min, m/z (positive ion) 360.2 [M+H].sup.+.
Example 83: Synthesis of 2-(4-(benzyloxy)phenyl)-6-(1-(methylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (83)
(367) ##STR00141##
(368) A suspension of 2-(4-(benzyloxy)phenyl)-6-(piperidin-4-yl)-1H-imidazo[4,5-b]pyridine 12 (0.020 g, 0.052 mmol) in DCM (1 mL) was cooled to 0 C. and then treated with DIPEA (0.009 mL, 0.05 mmol). After 5 minutes, methanesulfonyl chloride (0.004 mL, 0.05 mmol) was added and the mixture was stirred at 0 C. for 2 hours. Water (1 mL) was added and the mixture was warmed to room temperature. The mixture was extracted with DCM (310 mL) and the combined organic layers were washed with brine, dried (Na.sub.2SO.sub.4) and concentrated in vacuo to give the title compound (0.006 g, 25%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.19 (s, 1H), 8.23 (s, 1H), 8.19-8.08 (m, 2H), 7.83 (s, 1H), 7.53-7.46 (m, 2H), 7.45-7.39 (m, 2H), 7.39-7.31 (m, 1H), 7.25-7.12 (m, 2H), 5.21 (s, 2H), 3.76-3.67 (m, 2H), 2.92 (s, 3H), 2.90-2.75 (m, 3H), 1.99-1.88 (m, 2H), 1.80 (qd, J=12.5, 4.0 Hz, 2H). LCMS-B: rt 3.22 min, m/z (positive ion) 463.2 [M+H].sup.+.
Example 84: Synthesis of tert-butyl 4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (84)
(369) ##STR00142##
(370) 4-(Phenoxymethyl)benzaldehyde A20 (0.177 g, 0.834 mmol), tert-butyl 4-(5,6-diaminopyridin-2-yl)piperidine-1-carboxylate A89 (0.244 g, 0.834 mmol) and activated 4 sieves (1 g, before activation by heat-gun under vacuum) were combined in a flask, to which MeOH (10 mL) was added. The reaction mixture was heated at reflux for 4 days. The suspension was cooled to room temperature, filtered through a pad of Celite and the solvent was removed in vacuo. THF (10 mL) followed by (diacetoxyiodo)benzene (0.322 g, 1.00 mmol) were added under an atmosphere of nitrogen and the reaction was stirred at room temperature for 2 hours. The mixture was concentrated in vacuo and diluted with EtOAc (100 mL) and a saturated aqueous solution of NaHCO.sub.3 (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (100 mL). The combined organic fractions were washed with brine (100 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the crude product which was purified by silica gel chromatography (40 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound (0.191 g, 47%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.49 (br s, 1H), 8.27-8.16 (m, 2H), 7.95 (s, 1H), 7.62 (d, J=8.0 Hz, 2H), 7.39-7.25 (m, 2H), 7.17 (d, J=8.2 Hz, 1H), 7.10-7.01 (m, 2H), 6.95 (tt, J=7.3, 1.1 Hz, 1H), 5.19 (s, 2H), 4.09 (d, J=11.0 Hz, 2H), 3.03-2.76 (m, 3H), 1.87 (d, J=12.7 Hz, 2H), 1.66 (qd, J=12.6, 4.2 Hz, 2H), 1.43 (s, 9H). LCMS-A: rt 6.38 min, m/z (positive ion) 485.2 [M+H].sup.+.
Example 85: Synthesis of 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (85)
(371) ##STR00143##
(372) tert-Butyl 4-(2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate 84 (0.191 g, 0.394 mmol) was dissolved in DCM (15 mL) under an atmosphere of nitrogen. TFA (2 mL) was added and the mixture was stirred at room temperature for 20 hours. The reaction mixture was concentrated in vacuo and the resulting solid was dissolved in EtOAc (50 mL) and aqueous NaOH (2 M, 50 mL). The layers were separated and the aqueous phase was extracted with EtOAc (50 mL). The combined organic layers were washed with brine (50 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give the title compound (0.164 g, 100%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.27-8.16 (m, 2H), 7.91 (d, J=8.2 Hz, 1H), 7.61 (d, J=8.3 Hz, 2H), 7.31 (dd, J=8.7, 7.2 Hz, 2H), 7.12 (d, J=8.2 Hz, 1H), 7.06-7.02 (m, 2H), 6.95 (t, J=7.3 Hz, 1H), 5.19 (s, 2H), 3.08-3.01 (m, 2H), 2.82 (m, 1H), 2.61 (td, J=11.8, 2.3 Hz, 2H), 1.84-1.76 (m, 2H), 1.68 (qd, J=12.4, 3.9 Hz, 2H) NH proton signal not observed. LCMS-B: rt 2.97 min, m/z 385.3 (positive ion) [M+H].sup.+.
Example 86: Synthesis of 5-(1-methylpiperidin-4-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (86)
(373) ##STR00144##
(374) To a solution of 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 85 (0.030 g, 0.078 mmol) in anhydrous MeOH (6 mL) was added a 37% w/w aqueous solution of formaldehyde (0.017 mL, 0.23 mmol) under an atmosphere of nitrogen followed by sodium triacetoxyborohydride (0.066 g, 0.31 mmol). The mixture was stirred for 18 hours before the volatiles were removed in vacuo. The residue was diluted with EtOAc (20 mL) and a saturated aqueous solution of NaHCO.sub.3 (20 mL), the layers were separated and the aqueous phase extracted with EtOAc (20 mL). The combined organic layers were washed with brine (30 mL), dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to give a semi-solid which was taken up in a 1:1 mixture of DCM/Et.sub.2O (3 mL) and concentrated in vacuo to give the title compound (0.027 g, 87%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) Some signals appear as a mixture of rotamers, denoted with an (*): 13.52* (s, 0.75H), 13.07* (s, 0.25H), 8.22 (d, J=8.4 Hz, 2H), 7.96* (d, J=8.2 Hz, 0.7H), 7.84* (d, J=8.2 Hz, 0.3H), 7.65* (d, J=8.7 Hz, 0.6H), 7.61* (d, J=8.0 Hz, 1.4H), 7.31 (dd, J=8.7, 7.2 Hz, 2H), 7.17 (d, J=8.1 Hz, 1H), 7.04 (dd, J=8.6, 1.2 Hz, 2H), 6.99-6.92 (m, 1H), 5.19 (s, 2H), 2.92 (d, J=10.5 Hz, 2H), 2.78-2.68 (m, 1H), 2.23 (s, 3H), 2.11-1.94 (m, 2H), 1.90-1.81 (m, 4H). LCMS-A: rt 4.78 min, m/z (positive ion) 399.2 [M+H].sup.+.
Example 87: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(1-(methylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (87)
(375) ##STR00145##
(376) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 40 (0.050 g, 0.13 mmol) in THF (2 mL) was cooled to 0 C. To this solution, DIPEA (0.023 mL, 0.130 mmol) was added and then, after 5 minutes, methanesulfonyl chloride (0.010 mL, 0.130 mmol) was added. The mixture was stirred at 0 C. for 1 hour before water (2 mL) was added, and a fine precipitate formed. The volatiles were removed in vacuo and the remaining aqueous suspension was centrifuged for 10 minutes. The water was decanted from the solid pellet and a second aliquot of water (2 mL) was added. The mixture was centrifuged for 10 minutes, followed by decantation of the water and vacuum drying of the precipitate to give the title compound (0.050 g, 83%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.24 (s, 1H), 8.18-8.12 (m, 2H), 7.82 (d, J=7.9 Hz, 1H), 7.50-7.45 (m, 2H), 7.44-7.38 (m, 2H), 7.37-7.32 (m, 1H), 7.19-7.12 (m, 2H), 7.06 (d, J=7.8 Hz, 1H), 5.19 (s, 2H), 3.69 (dt, J=11.8, 3.0 Hz, 2H), 2.91 (s, 3H), 2.86 (td, J=12.1, 2.6 Hz, 3H), 2.03-1.96 (m, 2H), 1.84 (qd, J=12.4, 4.0 Hz, 2H). LCMS-B: rt 3.28 min, m/z (positive ion) 463.2 [M+H].sup.+.
Example 88: Synthesis of ethyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperidine-1-carboxylate (88)
(377) ##STR00146##
(378) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 40 (0.050 g, 0.13 mmol) in THF (2 mL) was cooled to 0 C. To this solution, DIPEA (0.023 mL, 0.13 mmol) was added and then, after 5 minutes, ethyl chloroformate (0.012 mL, 0.130 mmol) was added. The mixture was stirred at 0 C. for 1 hour before water (2 mL) was added, and a fine precipitate formed. The volatiles were removed in vacuo and the aqueous suspension centrifuged for 10 minutes. The water was decanted from the solid pellet and a second aliquot of water (2 mL) was added. The mixture was centrifuged for 10 minutes followed by decantation of the water and vacuum drying of the precipitate gave the title compound (0.048 g, 81%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.26 (br s, 1H), 8.17-8.10 (m, 2H), 7.88 (br s, 1H), 7.51-7.46 (m, 2H), 7.44-7.39 (m, 2H), 7.37-7.32 (m, 1H), 7.19 (d, J=8.4 Hz, 2H), 7.13 (d, J=8.2 Hz, 1H), 5.20 (s, 2H), 4.17-4.06 (m, 2H), 4.06 (q, J=7.1, Hz, 2H), 2.96 (td, J=8.0, 4.4 Hz, 3H), 1.88 (d, J=11.9 Hz, 2H), 1.68 (qd, J=12.6, 4.2 Hz, 2H), 1.20 (t, J=7.1 Hz, 3H). LCMS-B: rt 3.40 min, m/z (positive ion) 457.3 [M+H].sup.+.
Example 89: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(1-(cyclopropylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (89)
(379) ##STR00147##
(380) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 40 (0.050 g, 0.13 mmol) in THF (2 mL) was cooled to 0 C. To this solution, DIPEA (0.023 mL, 0.13 mmol) was added and then, after 5 minutes, cyclopropane sulfonyl chloride (0.013 mL, 0.13 mmol) was added. The mixture was stirred at 0 C. for 5 hours, then at room temperature for 72 hours. Water (2 mL) was added and a fine precipitate formed. The volatiles were removed in vacuo and the aqueous suspension was centrifuged for 10 minutes. The water was decanted from the solid pellet and a second aliquot of water (2 mL) was added. The mixture was centrifuged for 10 minutes, followed by decantation of the water. The aqueous supernatants were combined and extracted with EtOAc (210 mL). The organic layers were combined, washed with brine, dried (Na.sub.2SO.sub.4), filtered and concentrated in vacuo to reveal the title compound (0.043 g, 68%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.38 (br s, 1H), 8.20-8.11 (m, 2H), 7.90 (d, J=8.0 Hz, 1H), 7.54-7.45 (m, 2H), 7.44-7.38 (m, 2H), 7.38-7.31 (m, 1H), 7.18 (dd, J=10.3, 8.6 Hz, 3H), 5.21 (s, 2H), 3.79-3.69 (m, 2H), 3.04-2.88 (m, 3H), 2.68-2.58 (m, 1H), 2.06-1.96 (m, 2H), 1.83 (qd, J=12.7, 4.2 Hz, 2H), 1.05-0.91 (m, 4H). LCMS-B: rt 3.32 min, m/z (positive ion) 489.3 [M+H].sup.+.
Example 90: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(1-(ethylsulfonyl)piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (90)
(381) ##STR00148##
(382) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine 40 (0.050 g, 0.13 mmol) in THF (2 mL) was cooled to 0 C. To this was added DIPEA (0.023 mL, 0.13 mmol), then after 5 minutes, ethanesulfonyl chloride (0.012 mL, 0.13 mmol). The mixture was stirred at 0 C. for 2 hours before water (2 mL) was added, and a fine precipitate formed. The volatiles were removed in vacuo and the aqueous suspension was centrifuged for 10 minutes. Water was decanted from the solid pellet before the centrifuge/decantation process was repeated, first with another portion of water (2 mL) and then with a portion of Et.sub.2O (2 mL). Vacuum drying of the solid precipitate gave the title compound (0.048 g, 77%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) Some signals appear as a mixture of rotamers, denoted with an (*): 13.36* (s, 0.7H), 12.90* (s, 0.3H), 8.17-8.12 (m, 2H), 7.87* 7.93* (d, J=8.2 Hz, 0.6H), 7.81* (d, J=8.2 Hz, 0.4H), 7.51-7.46 (m, 2H), 7.44-7.38 (m, 2H), 7.38-7.32 (m, 1H), 7.19 (m, 3H), 5.21 (d, J=3.5 Hz, 2H), 3.78-3.70 (m, 2H), 3.13-3.05 (m, 2H), 3.01-2.89 (m, 3H), 2.02-1.94 (m, 2H), 1.81 (qd, J=12.2, 3.9 Hz, 2H), 1.25 (td, J=7.4, 2.8 Hz, 3H). LCMS-A: rt 5.59 min, m/z (positive ion) 477.2 [M+H].sup.+.
Example 91: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(4-(methylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (91)
(383) ##STR00149##
(384) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine 47 (0.020 g, 0.052 mmol) in DMF (1 mL) was cooled to 0 C. To this was added DIPEA (0.009 mL, 0.05 mmol), then after 5 minutes, methanesulfonyl chloride (0.0040 mL, 0.052 mmol). The mixture was stirred at 0 C. for 1 hour before water (6 mL) was added, and a fine precipitate formed. The suspension was centrifuged for 10 minutes before the supernatant was decanted off from the solid pellet. The centrifuge/decantation process was repeated, first with another portion of water (6 mL) and then with a portion of Et.sub.2O (3 mL). Vacuum drying of the solid precipitate gave the title compound (0.018 g, 75%) as a yellow solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.15 (s, 1H), 8.10-8.05 (m, 2H), 7.82 (d, J=8.8 Hz, 1H), 7.50-7.46 (m, 2H), 7.44-7.38 (m, 2H), 7.37-7.32 (m, 1H), 7.16 (d, J=8.9 Hz, 2H), 6.85 (d, J=8.9 Hz, 1H), 5.19 (s, 2H), 3.65 (t, J=5.0 Hz, 4H), 3.25 (t, J=5.0 Hz, 4H), 2.91 (s, 3H). LCMS-B: rt 3.12 min, m/z (positive ion) 464.3 [M+H].sup.+.
Example 92: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(4-(cyclopropylsulfonyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (92)
(385) ##STR00150##
(386) A solution of 2-(4-(benzyloxy)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine 47 (0.020 g, 0.052 mmol) in DMF (1 mL) was cooled to 0 C. To this was added DIPEA (0.009 mL, 0.052 mmol), then after 5 minutes, cyclopropanesulfonyl chloride (0.0053 mL, 0.052 mmol) was added. The reaction mixture was stirred at 0 C. for 1 hour before water (6 mL) was added, and a precipitate formed. The suspension was centrifuged for 10 minutes, and the solution was decanted off from the solid pellet. The centrifuge/decantation process was repeated, first with another portion of water (6 mL) and then with a portion of Et.sub.2O (3 mL). Vacuum drying of the solid precipitate gave the title compound (0.017 g, 67%) as an off-white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.00 (br s, 1H), 8.09-8.04 (m, 2H), 7.81 (br s, 1H), 7.50-7.46 (m, 2H), 7.44-7.39 (m, 2H), 7.37-7.32 (m, 1H), 7.15 (d, J=8.4 Hz, 2H), 6.83 (d, J=8.8 Hz, 1H), 5.19 (s, 2H), 3.66-3.61 (m, 4H), 2.69-2.60 (m, 1H), 1.03-0.92 (m, 4H). Four proton signals from the piperazine ring are obscured by the water signal. LCMS-B: rt 3.25 min, m/z (positive ion) 490.2 [M+H].sup.+.
Example 93: Synthesis of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)-N-methylacetamide (93)
(387) ##STR00151##
(388) To a suspension of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetic acid 77 (0.050 g, 0.14 mmol), EDCI.HCl (0.080 g, 0.42 mmol) and DMAP (0.051 g, 0.42 mmol) in dry DCM (5 mL) under a nitrogen atmosphere was added a 33% w/w solution of methylamine in EtOH (0.021 mL, 0.17 mmol). The solution was stirred for 17 hours before being diluted with DCM (5 mL). The mixture was washed with 1 M HCl (210 mL), a saturated aqueous solution of NaHCO.sub.3 (10 mL), brine and concentrated in vacuo. The crude material was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH in EtOAc) to give the title compound (0.010 g, 19%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.35 (br s, 1H), 8.23 (br s, 1H), 8.18 (d, J=7.8 Hz, 2H), 8.08-8.01 (m, 1H), 7.49 (d, J=7.2 Hz, 2H), 7.44-7.39 (m, 2H), 7.38-7.33 (m, 1H), 7.20 (d, J=8.5 Hz, 2H), 7.14-7.09 (m, 1H), 5.21 (s, 2H), 3.85 (s, 2H), 2.62 (d, J=4.6 Hz, 3H). LCMS-B: rt 3.07 min, m/z (positive ion) 373.2 [M+H].sup.+.
Example 94: Synthesis of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)-N,N-dimethylacetamide (94)
(389) ##STR00152##
(390) To a solution of 2-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-7-yl)acetic acid 77 (0.050 g, 0.14 mmol), EDCI.HCl (0.080 g, 0.42 mmol) and DMAP (0.051 g, 0.42 mmol) in dry DCM (5 mL) under a nitrogen atmosphere was added a 33% w/w solution of dimethylamine in EtOH (0.030 mL, 0.17 mmol). The solution was stirred for 17 hours. The mixture was diluted with DCM (5 mL) and washed with 1 M HCl (210 mL), a saturated aqueous solution of NaHCO.sub.3 (10 mL), brine and concentrated in vacuo. The crude material was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-20% MeOH in EtOAc) to give the title compound (0.015 g, 28%) as a white solid. .sup.1H NMR (400 MHz, d.sub.6-DMSO): some signals appear as a mixture of rotamers, denoted with an (*) 13.36* (br s, 0.7H), 12.67* (br s, 0.3H), 8.24* (s, 0.4H), 8.17* (d, J=8.8 Hz, 2.6H), 7.49 (d, J=7.2 Hz, 2H), 7.45-7.38 (m, 2H), 7.39-7.32 (m, 1H), 7.25* (s, 0.5H), 7.20* (d, J=8.5 Hz, 1.5H), 7.04* (d, J=4.5 Hz, 0.7H), 6.98* (s, 0.3H), 5.21 (s, 2H), 4.07 (s, 2H), 3.12 (s, 3H), 2.86 (s, 3H). LCMS-B: rt 3.10 min, m/z (positive ion) 387.2 [M+H].sup.+.
Example 95: Synthesis of tert-butyl 4-(2-(4-(benzylthio)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (95)
(391) ##STR00153##
tert-Butyl 4-(2-(4-(benzylthio)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate (95)
(392) A solution of sodium dithionite (85%, 0.23 g, 1.1 mmol), tert-butyl 4-(6-amino-5-nitropyridin-2-yl)piperazine-1-carboxylate A117 (0.12 g, 0.37 mmol) and benzyl 4-formylphenyl sulfide (0.093 g, 0.41 mmol) in EtOH (1.6 mL) and water (1.0 mL) was bubbled with nitrogen for 5 minutes and then heated under microwave irradiation at 70 C. for 16 hours and then at 110 C. for 1.3 hours. The reaction mixture was cooled to room temperature and treated with a 5 M ammonium hydroxide solution (2.0 mL) and stirred at ambient temperature for 1.5 hours. The suspension was filtered, washed with water (210 mL) and the solid dried in vacuo to give the title compound as a yellow solid (0.12 g, 65%). .sup.1H NMR (300 MHz, d.sub.6-DMSO) b 8.03 (d, J=8.58 Hz, 2H), 7.83 (d, J=8.80 Hz, 1H), 7.38-7.47 (m, 4H), 7.20-7.37 (m, 4H), 6.80 (d, J=9.02 Hz, 1H), 4.33 (s, 2H), 3.43-3.57 (m, 8H), 1.44 (s, 9H).
Example 96: Synthesis of 2-(4-(benzylthio)phenyl)-5-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (96)
(393) ##STR00154##
(394) To a solution of tert-butyl 4-(2-(4-(benzylthio)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)piperazine-1-carboxylate 95 (0.0020 g, 0.040 mmol) in DCM (2 mL) was added TFA (0.5 mL). The mixture was stirred at ambient temperature for 2 hours before the volatiles were removed in vacuo. The residue was loaded onto an SCX cartridge (1 g). which was washed with MeOH (10 mL) and then with 2 M ammonia in MeOH (10 mL). The basic fractions were combined and the solvent was removed in vacuo to give the title compound as yellow oil (0.015 g, 93%). .sup.1H NMR (300 MHz, CD.sub.3OD) 7.91 (d, J=8.36 Hz, 2H), 7.76 (d, J=8.80 Hz, 1H), 7.18-7.45 (m, 7H), 6.80 (d, J=8.80 Hz, 1H), 4.23 (s, 2H), 3.53-3.63 (m, 4H), 2.95-3.02 (m, 4H).
Example 97: Synthesis of 2-(4-(benzyloxy)phenyl)-5-(1-(ethylsulfonyl)-1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine (97)
(395) ##STR00155##
(396) A suspension of 2-(4-(benzyloxy)phenyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine 45 (0.038 g, 0.10 mmol) in THF (1.5 mL) was cooled to 0 C. To this suspension was added DIPEA (0.017 mL, 0.10 mmol) and then, after 5 minutes, ethanesulfonyl chloride (0.010 mL, 0.10 mmol). The mixture was stirred at 0 C. for 6 hours and then overnight at room temperature. An additional portion of DIPEA (0.0085 mL, 0.050 mmol) was added, followed by ethanesulfonyl chloride (0.005 mL, 0.050 mmol) after 5 minutes. The reaction mixture was stirred at 0 C. for 6 hours and then at room temperature overnight. Water (1.5 mL) was added and the volatiles removed in vacuo. The resulting precipitate was filtered, washed with water (20 mL) then air dried to give the crude material as an orange solid which was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as an off-white solid (0.010 g, 21%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.43 (brs, 1H), 8.19-8.14 (m, 2H), 7.95 (s, 1H), 7.51-7.47 (m, 3H), 7.46-7.39 (m, 2H), 7.38-7.33 (m, 1H), 7.20 (d, J=8.4 Hz, 2H), 6.70 (s, 1H), 5.21 (s, 2H), 4.02-3.98 (m, 2H), 3.49 (t, J=5.6 Hz, 2H), 3.14 (q, J=7.4 Hz, 2H), 2.76 (d, J=1.6 Hz, 2H), 1.24 (t, J=7.2 Hz, 3H). LCMS-A: rt 5.81 min, m/z (positive ion) 475.2 [M+H].sup.+.
Example 98: Synthesis of 1-(4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3,6-dihydropyridin-1 (2H)-yl)ethan-1-one (98)
(397) ##STR00156##
(398) A suspension of 2-(4-(benzyloxy)phenyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-3H-imidazo[4,5-b]pyridine 45 (0.063 g, 0.13 mmol) in THF (3.5 mL) was cooled to 0 C. To this was added DIPEA (0.051 g, 0.39 mmol) and then, after 5 minutes, acetyl chloride (0.015 g, 0.20 mmol) was added. The reaction mixture was stirred at 0 C. for 2.75 hours. Water (3.5 mL) was added and the volatiles were removed in vacuo. The resulting precipitate was filtered, washed with water (20 mL) and air dried to give the crude material as an orange solid which was purified by silica gel chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C., then 0-15% MeOH in EtOAc) to yield the title compound as a pale yellow solid (0.031 g, 56%). .sup.1H NMR (400 MHz, d.sub.6-DMSO): some signals appear as a mixture of rotamers, denoted with an (*) 13.34 (br s, 1H), 8.19-8.14 (m, 2H), 7.93 (d, J=8.0 Hz, 1H), 7.52-7.45 (m, 3H), 7.45-7.39 (m, 2H), 7.38-7.33 (m, 1H), 7.23-7.17 (m, 2H), 6.67 (s, 1H), 5.21 (s, 2H), 4.20 (dd, J=23.5, 3.2 Hz, 2H), 3.68 (dt, J=11.8, 5.6 Hz, 2H), 2.75 (s, 1H), 2.64 (s, 1H), 2.10 (s, 1.5H*), 2.06 (s, 1.5H*). LCMS-A: rt 5.40 min, m/z (positive ion) 425.2 [M+H].sup.+.
Example 99: Synthesis of 5-(1-methylpiperidin-3-yl)-2-(4-(phenoxymethyl)phenyl)-3H-imidazo[4,5-b]pyridine (99)
(399) ##STR00157##
(400) To a solution of 2-(4-(phenoxymethyl)phenyl)-5-(piperidin-3-yl)-3H-imidazo[4,5-b]pyridine 35 (0.030 g, 0.078 mmol) in anhydrous MeOH (6 mL) was added a 37% w/w aqueous solution of formaldehyde (0.019 mL, 0.23 mmol) followed by sodium triacetoxyborohydride (0.066 g, 0.31 mmol). The mixture was stirred at room temperature for 18 hours and the volatiles were removed in vacuo. The residue was diluted with EtOAc (30 mL) and a saturated aqueous solution of NaHCO.sub.3 (30 mL). The aqueous layer was extracted with EtOAc (230 mL), then the combined organic layers were washed with brine (50 mL), dried (Na.sub.2SO.sub.4), then concentrated in vacuo to give the title compound as a pale brown oil (0.027 g, 87%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 13.50 (br s, 1H), 8.24-8.19 (m, 2H), 7.92 (d, J=7.5 Hz, 1H), 7.62 (d, J=8.0 Hz, 2H), 7.35-7.28 (m, 2H), 7.17 (d, J=8.2 Hz, 1H), 7.07-7.02 (m, 2H), 6.96 (tt, J=7.3, 1.0 Hz, 1H), 5.19 (s, 2H), 3.05-2.99 (m, 1H), 2.99-2.93 (m, 1H), 2.81 (d, J=11.0 Hz, 1H), 2.20 (s, 3H), 2.14-2.06 (m, 1H), 1.95-1.89 (m, 1H), 1.86 (dd, J=11.2, 2.8 Hz, 1H), 1.74 (dt, J=11.7, 3.1 Hz, 1H), 1.70-1.50 (m, 2H). LCMS-A: rt 4.76 min, m/z (positive ion) 399.2 [M+H].sup.+.
Example 100: Synthesis of 2-(4-(benzyloxy)phenyl)-6-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (100)
(401) ##STR00158##
a) tert-Butyl 4-(6-amino-5-nitropyridin-3-yl)piperazine-1-carboxylate (A139)
(402) 5-Bromo-3-nitropyridin-2-amine (0.250 g, 1.15 mmol), 1-boc-piperazine (0.320 g, 1.72 mmol) and RuPhos palladacycle precatalyst (19 mg, 2 mol %) were loaded into a tube and flushed with nitrogen. A solution of LiHMDS (1 M in toluene, 3.0 mL, 3.0 mmol) was added and the mixture was stirred at room temperature under nitrogen. After 30 minutes, anhydrous THF (3 mL) was added and stirring was continued at room temperature under nitrogen. After 18 hours, the mixture was added to a saturated aqueous solution of ammonium chloride (10 mL), diluted with EtOAc (30 mL) and water (20 mL), and the resulting mixture was filtered. The aqueous phase was extracted with EtOAc (230 mL), the pooled organic phases were washed with brine (50 mL), dried over sodium sulfate and the volatiles removed under reduced pressure. The crude material was purified by column chromatography (24 g SiO.sub.2 cartridge, 0-60% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a red solid (40 mg, 11%). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.25 (d, J=2.8 Hz, 1H), 7.92 (d, J=2.8 Hz, 1H), 6.46 (s, 2H), 3.63-3.57 (m, 4H), 3.06-2.99 (m, 4H), 1.48 (s, 9H). LCMS-A: rt 6.19 min, m/z (positive ion) 324.2 [M+H].sup.+.
b) tert-Butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperazine-1-carboxylate (A140)
(403) A mixture of tert-butyl 4-(6-amino-5-nitropyridin-3-yl)piperazine-1-carboxylate A139 (40 mg, 0.12 mmol), 4-(benzyloxy)benzaldehyde A8 (32 mg, 0.15 mmol), sodium dithionite (54 mg, 0.31 mmol), water (1 mL) and EtOH (1.5 mL) was irradiated in the microwave (110 C./20 minutes). The crude material was irradiated again in the microwave (110 C./20 minutes). The crude mixture was added to water (25 mL) and extracted with EtOAc (325 mL). The pooled organic phases were washed with brine (50 mL), dried over sodium sulfate and the volatiles evaporated in vacuo. The crude material was purified by column chromatography (4 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.), giving to give a pale yellow solid. The crude solid was washed with diethyl ether (20.5 mL) and dried under vacuum to give the title compound as a pale yellow solid (8.9 mg, 15%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.17-8.08 (m, 3H), 7.53-7.38 (m, 5H), 7.38-7.31 (m, 1H), 7.18 (d, J=8.8 Hz, 2H), 5.20 (s, 2H), 3.53-3.49 (m, 4H), 3.14-3.07 (m, 4H), 1.43 (s, 9H), NH peak not observed. LCMS-A: rt 5.72 min, m/z (positive ion) 486.3 [M+H].sup.+; m/z (negative ion) 484.2 [MH].sup..
c) 2-(4-(Benzyloxy)phenyl)-6-(piperazin-1-yl)-3H-imidazo[4,5-b]pyridine (100)
(404) A mixture of tert-butyl 4-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-6-yl)piperazine-1-carboxylate A140 (8.4 mg, 0.017 mmol), DCM (2 mL) and TFA (0.5 mL) were stirred at room temperature. After three hours, the mixture was diluted with 5% w/v aqueous solution of sodium hydroxide (25 mL) and extracted with EtOAc (325 mL). The pooled organic phases were washed with brine (50 mL), dried over sodium sulfate and concentrated in vacuo to give the title compound as an off-white solid (7 mg, >99%). .sup.1H NMR (400 MHz, CD.sub.3OD) 8.17 (d, J=2.5 Hz, 1H), 8.07-8.02 (m, 2H), 7.51 (d, J=2.5 Hz, 1H), 7.49-7.45 (m, 2H), 7.42-7.36 (m, 2H), 7.35-7.30 (m, 1H), 7.19-7.14 (m, 2H), 5.19 (s, 2H), 3.23-3.17 (m, 4H), 3.09-3.03 (m, 4H). LCMS-A: rt 4.55 min, m/z (positive ion) 386.2 [M+H].sup.+; m/z (negative ion) 384.2 [MH].sup..
Example 101: Synthesis of 1-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-4-methylpiperidin-4-ol (101)
(405) ##STR00159##
a) tert-Butyl 4-hydroxy-4-methylpiperidine-1-carboxylate (A141)
(406) tert-Butyl 4-oxopiperidine-1-carboxylate (1.0 g, 5.0 mmol) was dissolved in anhydrous Et.sub.2O (10 mL) and cooled to 10 C. under nitrogen. A solution of methylmagnesium bromide (3 M in Et.sub.2O, 2.5 mL, 7.5 mmol) was added drop-wise and the mixture stirred for 5 minutes. The cooling bath was removed and the slurry was stirred at room temperature for 2 hours. The mixture was quenched with a saturated aqueous solution of ammonium chloride (10 mL) and then diluted with water (20 mL) and diethyl ether (20 mL). The aqueous phase was extracted with diethyl ether (230 mL), the pooled organic extracts were washed with brine (50 mL), dried over sodium sulfate and concentrated in vacuo to give the title compound as a colourless oil (1.05 g, 97%). .sup.1H NMR (400 MHz, CDCl.sub.3) 3.76-3.64 (m, 2H), 3.29-3.16 (m, 2H), 1.66 (s, 1H), 1.45 (s, 9H), 1.25 (s, 3H) 4H obscured by solvent.
b) 4-Methylpiperidin-4-ol hydrochloride (A142)
(407) tert-Butyl 4-hydroxy-4-methylpiperidine-1-carboxylate A141 (1.05 g, 4.90 mmol), 1,4-dioxane (30 mL) and 4 M HCl in 1,4-dioxane (10 mL) were stirred together for 3 hours. The mixture was concentrated in vacuo, the solid residue suspended in diethyl ether (20 mL), the solvent decanted from the solid and the solid washed with diethyl ether (20 mL). The solid was dried under vacuum to give the title compound as a white solid (584 mg, 79%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.97 (br s, 1H), 8.85 (br s, 1H), 4.66 (br s, 1H), 3.08-2.93 (m, 4H), 1.74-1.53 (m, 4H), 1.15 (s, 3H). LCMS-A rt: 1.38 min, m/z (positive ion) 116.3 [M+H].sup.+.
c) 1-(6-Amino-5-nitropyridin-2-yl)-4-methylpiperidin-4-ol (A143)
(408) 6-Chloro-3-nitropyridin-2-amine A44 (174 mg, 1.00 mmol), 4-methylpiperidin-4-ol hydrochloride A142 (167 mg, 1.10 mmol), potassium carbonate (415 mg, 3.00 mmol) and DMF (5 mL) were heated to 100 C. for 3 hours. The mixture was returned to room temperature, diluted with water (30 mL) and cooled at 4 C. for 3 hours. The precipitate was collected by filtration to give the title compound as a yellow solid (152 mg, 60%). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.16 (d, J=9.5 Hz, 1H), 6.11 (d, J=9.5 Hz, 1H), 4.15 (s, 2H), 3.53-3.35 (m, 2H), 1.70-1.60 (m, 4H), 1.58 (s, 3H), 1.21 (s, 1H), NH.sub.2 protons not observed. LCMS-A: rt 5.29 min, m/z (positive ion) 253.2 [M+H].sup.+.
d) 1-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-4-methylpiperidin-4-ol (101)
(409) 1-(6-Amino-5-nitropyridin-2-yl)-4-methylpiperidin-4-ol A143 (150 mg, 0.60 mmol), 4-(benzyloxy)benzaldehyde A8 (151 mg, 0.714 mmol), sodium dithionite (259 mg, 1.50 mmol), water (2 mL) and EtOH (3 mL) were stirred in a sealed vessel at 70 C. After 18 hours, the mixture was cooled to room temperature, diluted with water (30 mL) and extracted with EtOAc (325 mL). The pooled organic phases were washed with brine (30 mL), dried over sodium sulfate and concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO2 cartridge, 0-20% MeOH in DCM) to give the title compound as a yellow solid (25 mg, 10%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 12.83 (s, 1H), 8.05 (d, J=8.9 Hz, 2H), 7.73 (d, J=8.9 Hz, 1H), 7.53-7.32 (m, 5H), 7.12 (d, J=8.9 Hz, 2H), 6.75 (d, J=9.2 Hz, 1H), 5.18 (s, 2H), 4.33 (s, 1H), 3.87-3.72 (m, 2H), 1.57-1.45 (m, 4H), 1.15 (s, 3H), 2H obscured by solvent. LCMS-A: rt 4.97 min, m/z (positive ion) 415.2 [M+H].sup.+, m/z (negative ion) 413.2 [MH].sup..
Example 102: Synthesis of 2-(phenoxymethyl)-4-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)thiazole (102)
(410) ##STR00160##
a) Ethyl 2-(phenoxymethyl)thiazole-4-carboxylate (A144)
(411) 2-Phenoxyethanethioamide (0.858 g, 5.13 mmol) and ethyl bromopyruvate (0.645 mL, 5.13 mmol) were dissolved in acetone (40 mL) and anhydrous magnesium sulfate (0.617 g, 5.13 mmol) was added. The reaction mixture was then heated at reflux for 18 hours. The mixture was cooled to room temperature and filtered through Celite and the filter cake was washed with EtOAc (520 mL). The combined organic washes were concentrated in vacuo to give the crude material as a brown gum which was purified by column chromatography (40 g SiO2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.) to give the title compound as a pale yellow solid (631 mg, 47%). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.20 (s, 1H), 7.34-7.28 (m, 2H), 7.04-6.96 (m, 3H), 5.41 (s, 2H), 4.44 (q, J=7.1 Hz, 2H), 1.42 (t, J=7.2 Hz, 3H). LCMS-A: rt 6.50 min, m/z (positive ion) 264.1 [M+H].sup.+.
b) 2-(Phenoxymethyl)thiazole-4-carbaldehyde (A145)
(412) Ethyl 2-(phenoxymethyl)thiazole-4-carboxylate A144 (0.300 g, 1.14 mmol) was dissolved in DCM (10 mL) and cooled to 78 C. DIBAL-H (25 wt/% in toluene, 0.814 mL, 1.71 mmol) was added drop-wise and the mixture stirred under nitrogen at 78 C. for 3 hours. The mixture was quenched with a 10% w/v aqueous solution of citric acid (20 mL), the cooling bath was removed and the mixture stirred at room temperature for 20 minutes. The mixture was diluted with water (10 mL) and DCM (20 mL), filtered, and the filtrate aqueous phase extracted with DCM (220 mL). The pooled organic extracts were washed with brine (50 mL), dried over sodium sulfate and concentrated in vacuo. Purification by column chromatography (40 g SiO.sub.2 cartridge, 0-10% EtOAc in DCM) resulted in 2-(phenoxymethyl)thiazole-4-carbaldehyde (125 mg, 0.570 mmol) this was combined with tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (183 mg, 0.627 mmol) and 3 molecular sieves (500 mg) and refluxed in MeOH (10 mL) under air. After 65 hours the mixture was cooled to room temperature and diluted with MeOH (20 mL). The mixture was filtered, the solids washed with MeOH (20 mL) and the combined filtrates concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-20% MeOH in DCM) and the fractions containing product were combined and the solvent removed in vacuo. The resulting residue was washed with diethyl ether. The organic washes and the crude solid were combined, then purified by column chromatography (12 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.). The resulting material was slurried in diethyl ether (5 mL), the mixture diluted with petroleum benzine 40-60 C. (20 mL), the solvents were decanted and the solid dried under vacuum to give the title compound as an off-white solid (26 mg, 5%). The isolated material was used in the next step without further purification. LCMS-A: rt 3.36 min, m/z (positive ion) 492.2 [M+H].sup.+, m/z (negative ion) 490.2 [MH].sup..
c) 2-(Phenoxymethyl)-4-(6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridin-2-yl)thiazole (102)
(413) tert-Butyl 4-(2-(2-(phenoxymethyl)thiazol-4-yl)-2,3-dihydro-1H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A145 (25 mg, 0.051 mmol), DCM (4 mL) and TFA (1 mL) were stirred at room temperature for 18 hours. The mixture was quenched with 5% w/v aqueous sodium hydroxide (25 mL) and the volatiles were removed in vacuo. The resulting solid was collected by filtration, washed with water (22 mL) and air dried to give the title compound as a white solid (10 mg, 53%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.49 (s, 1H), 8.27 (d, J=1.6 Hz, 1H), 7.73 (s, 1H), 7.39-7.32 (m, 2H), 7.15-7.10 (m, 2H), 7.05-6.99 (m, 1H), 5.55 (s, 2H), 3.05 (d, J=11.7 Hz, 2H), 2.81-2.71 (m, 1H), 2.66-2.57 (m, 2H), 1.75 (d, J=12.4 Hz, 2H), 1.59 (qd, J=12.2, 3.9 Hz, 2H), 2NH protons not observed. LCMS-A: rt 4.52 min, m/z (positive ion) 392.2 [M+H].sup.+.
Example 103: Synthesis of 7-(2-(4-(benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (103)
(414) ##STR00161##
a) 6-(3-Methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)-3-nitropyridin-2-amine (A146)
(415) 6-Chloro-3-nitropyridin-2-amine A44 (0.15 g, 0.86 mmol), 3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (125 mg, 0.907 mmol), DMF (2 mL) and DIPEA (0.301 mL, 1.73 mmol) were irradiated in the microwave at 100 C. for 30 minutes. The cooled mixture was added to water (40 mL), the precipitate collected by filtration, washed with water (2 mL) and air dried to give the title compound as a yellow solid (194 mg, 82%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.15 (d, J=9.5 Hz, 1H), 7.95 (br s, 2H), 6.52 (d, J=9.5 Hz, 1H), 5.05 (s, 2H), 4.15 (t, J=5.5 Hz, 2H), 4.00 (t, J=5.4 Hz, 2H), 2.30 (s, 3H). LCMS-B rt 2.73 min, m/z (positive ion) 276.1 [M+H].sup.+.
b) 7-(2-(4-(Benzyloxy)phenyl)-3H-imidazo[4,5-b]pyridin-5-yl)-3-methyl-5, 6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (103)
(416) 6-(3-Methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)-3-nitropyridin-2-amine A146 (0.100 g, 0.363 mmol), 4-(benzyloxy)benzaldehyde A8 (0.081 g, 0.38 mmol), sodium dithionite (0.190 g, 1.09 mmol), water (1 mL) and EtOH (1.6 mL) were stirred in a sealed vessel at 70 C. After 18 hours, the mixture was added to 5 M aqueous ammonia (10 mL), the precipitate collected by filtration and washed with 5 M aqueous ammonia (3 mL). Purification of the precipitate by column chromatography (Isolera Biotage, 4 g SiO.sub.2 cartridge, 0-20% MeOH in DCM) gave the title compound as a yellow solid (48 mg, 30%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 12.96 (s, 1H), 8.07 (d, J=8.8 Hz, 2H), 7.83 (d, J=8.8 Hz, 1H), 7.48 (d, J=7.0 Hz, 2H), 7.44-7.38 (m, 2H), 7.38-7.31 (m, 1H), 7.15 (d, J=8.9 Hz, 2H), 6.98 (d, J=8.8 Hz, 1H), 5.19 (s, 2H), 4.87 (s, 2H), 4.10-3.97 (m, 4H), 2.30 (s, 3H). LCMS-B: rt 3.17 min, m/z (positive ion) 438.2 [M+H].sup.+.
Example 104: Synthesis of 2-(1-benzyl-1H-pyrazol-4-yl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (104)
(417) ##STR00162##
a) 1-Benzyl-4-iodo-1H-pyrazole (A147)
(418) 4-Iodo-1H-pyrazole (1.00 g, 5.16 mmol) in DMF (15 mL) was cooled to 0 C. before sodium hydride (60% w/w dispersion in mineral oil, 258 mg, 6.44 mmol) was added. After 15 minutes, benzyl bromide (0.674 mL, 6.44 mmol) was added and the mixture stirred at room temperature. After two hours, the mixture was added to water (200 mL), cooled at 4 C. for one hour then filtered. The collected solid was washed with cyclohexane (23 mL) and air dried to give the title compound as a white solid (0.859 g, 59%). .sup.1H NMR (400 MHz, CDCl.sub.3) 7.51 (s, 1H), 7.36 (s, 1H), 7.35-7.28 (m, 3H), 7.21-7.17 (m, 2H), 5.27 (s, 2H). LCMS-B: 3.48 min, m/z (positive ion) 285.1 [M+H].sup.+.
b) 1-Benzyl-1H-pyrazole-4-carbaldehyde (A148)
(419) 1-Benzyl-4-iodo-1H-pyrazole A147 (859 mg, 3.02 mmol) in THF (5 mL) was cooled to 0 C. under nitrogen before a 2.0 M solution of isopropylmagnesium chloride in THF (1.66 mL, 3.33 mmol) was added. After 1 hour, DMF (0.5 mL) was added. The mixture was stirred for 30 minutes at 0 C. then a further 30 minutes at room temperature. The mixture was quenched with a saturated aqueous solution of ammonium chloride (10 mL), diluted with water (20 mL) and extracted with CHCl.sub.3 (325 mL). The pooled organics were washed with brine (50 mL), dried with sodium sulfate and concentrated in vacuo. The crude material was purified by column chromatography (12 g SiO.sub.2 cartridge, 0-50% EtOAc in hexanes) to give the title compound as a colourless oil (170 mg, 30%). .sup.1H NMR (400 MHz, CDCl.sub.3) 9.83 (s, 1H), 8.00 (s, 1H), 7.88 (s, 1H), 7.42-7.33 (m, 3H), 7.29-7.25 (m, 2H), 5.33 (s, 2H). LCMS-B: rt 3.10 min, m/z (positive ion) 187.1 [M+H].sup.+.
c) tert-Butyl 4-(2-(1-benzyl-1H-pyrazol-4-yl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate (A149)
(420) 1-Benzyl-1H-pyrazole-4-carbaldehyde A148 (85.0 mg, 0.456 mmol), tert-butyl 4-(5,6-diaminopyridin-3-yl)piperidine-1-carboxylate A32 (133 mg, 0.456 mmol) and absolute EtOH (1.5 mL) were heated to 80 C. After 18 hours, the mixture was cooled and the solvent evaporated. THF (1 mL) and PhI(OAc).sub.2 (147 mg, 0.456 mmol) were added and the mixture stirred for three hours at room temperature. The mixture was added to water (30 mL) and extracted with EtOAc (330 mL). The pooled organic phases were washed with brine, dried over sodium sulfate and concentrated in vacuo. Purification by column chromatography (4 g SiO.sub.2 cartridge, 0-100% EtOAc in hexanes, then 0-20% MeOH in EtOAc) gave the title compound as an orange-brown solid (71 mg, 34%). LCMS-B: rt 3.23 min, m/z (positive ion) 459.3 [M+H].sup.+.
d) 2-(1-Benzyl-1H-pyrazol-4-yl)-6-(piperidin-4-yl)-3H-imidazo[4,5-b]pyridine (104)
(421) tert-Butyl 4-(2-(1-benzyl-1H-pyrazol-4-yl)-3H-imidazo[4,5-b]pyridin-6-yl)piperidine-1-carboxylate A149 (0.070 g, 0.15 mmol), DCM (10 mL) and TFA (1 mL) were combined and stood for 2.5 hours. The mixture was quenched with 10% w/v aqueous sodium hydroxide (20 mL) and the volatiles removed in vacuo. The residue was extracted with EtOAc (330 mL), the pooled organics were washed with brine (30 mL), dried over sodium sulfate and concentrated in vacuo to give the title compound as an off-white solid (40 mg, 73%). .sup.1H NMR (400 MHz, d.sub.6-DMSO) 8.48 (s, 1H), 8.14 (s, 1H), 8.13-8.12 (m, 1H), 7.69 (s, 1H), 7.41-7.29 (m, 5H), 5.44 (s, 2H), 3.09-3.01 (m, 2H), 2.77-2.68 (m, 1H), 2.66-2.58 (m, 2H), 1.77-1.70 (m, 2H), 1.60 (qd, J=12.3, 3.9 Hz, 2H), 2H not observed. LCMS-B: rt 2.75 min, m/z (positive ion) 359.3 [M+H].sup.+, m/z (negative ion) 357.2 [MH].sup..
Intermediate A150: Synthesis of tert-butyl 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine-3-carboxylate
(422) ##STR00163##
tert-butyl 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine-3-carboxylate (A150)
(423) To a solution of 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine 17 (25.3 g, 75.2 mmol) in anhydrous THF (200 mL) was added di-tert-butyl dicarbonate (25.9 g, 113 mmol), DMAP (0.919 g, 7.52 mmol) and Et.sub.3N (15.7 mL, 113 mmol) and the mixture was stirred at 65 C. for 2 hours. The mixture was cooled, concentrated in vacuo, and the resulting oily residue was partitioned between EtOAc (1 L) and a 1:1 mixture of water: saturated aqueous solution of NH.sub.4Cl (1 L). The mixture was filtered and the biphasic filtrate mixture was separated. The organic layer was washed with an aqueous 0.5 M HCl solution (1 L), brine (1 L), dried (Na.sub.2SO.sub.4) and concentrated in vacuo to give the title compound (30.8 g, 94%). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.20 (d, J=8.4 Hz, 1H), 7.68-7.62 (m, 2H), 7.47-7.33 (m, 5H), 7.31 (d, J=8.5 Hz, 1H), 7.09-7.04 (m, 2H), 5.15 (s, 2H), 1.47 (s, 9H).
Examples 105-107
Suzuki on tert-butyl 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine-3-carboxylate (A150)
(424) ##STR00164##
(425) General Procedure G:
(426) A suspension of tert-butyl 2-(4-(benzyloxy)phenyl)-5-chloro-3H-imidazo[4,5-b]pyridine-3-carboxylate A150 (0.100 g, 0.229 mmol), a boronic acid or boronic pinacol ester (0.41 mmol), XPhos (22 mg, 0.046 mmol) and K.sub.3PO.sub.4 (61 mg, 0.29 mmol, 1.25 equiv) in DME (3.0 mL) was sonicated for 10 minutes before Pd.sub.2(dba).sub.3 (21 mg, 0.023 mmol) was added. The reaction mixture was irradiated in the microwave at 110 C. for 20 minutes, then loaded onto silica gel and separated by column chromatography (24 g SiO.sub.2 cartridge, 0-100% EtOAc in petroleum benzine 40-60 C.). The resulting residue was dissolved in DCM (5 mL), TFA (0.5 mL) was added and the mixture stirred at room temperature for 3 hours. The volatiles were removed under reduced pressure and the residue was loaded onto an SCX cartridge (1 g). The cartridge was washed with MeOH (15 mL) and the product was eluted with 0.5 M NH.sub.3 in 1,4-dioxane (15 mL). The fractions containing product were combined and the volatiles removed in vacuo to yield the desired product.
(427) TABLE-US-00006 TABLE E Example Product Name and Structure LCMS data Method 105
PRMT5 Biochemical Assay
(428) Compounds of the invention may be tested for in vitro activity in the following assay: A histone H4 derived peptide is used as substrate (amino acid sequence: Ser-Gly-Arg-Gly-Lys-Gly-Gly-Lys-Gly-Leu-Gly-Lys-Gly-Gly-Ala-Lys-Arg-His-Arg-Lys-Val-N H.sub.2). Full-length PRMT5 enzyme (NCBI Reference sequence NP_006100.2) was co-expressed with His.sub.6-MEP50 in insect cells and purified via Nickel immobilized metal affinity and gel filtration chromatography (the enzyme).
(429) The 6 L assay reactions are run in Greiner brand black 384-well low volume plates. All reactions contained assay buffer (phosphate buffered saline, 0.01% (v/v) Tween-20, 0.01% (w/v) albumin from chicken egg white, 1 mM dithiothreitol, 200 nM peptide substrate, 1 M S-Adenosyl methionine, and 15 ng/reaction enzyme, with the enzyme being omitted from negative control reactions. Compounds were added in a volume of 100 nL from dilution series prepared in DMSO, positive and negative control reactions receiving the same volume DMSO without compound. The plates were sealed with adhesive seals and incubated for 4 hours at 37 C. Reaction progress was measured using the Transcreener EPIGEN methyltransferase assay (BellBrook Labs, Madison, Wis.) as recommended by the manufacturer. To each reaction 2 L detection mix were added, containing coupling enzymes, fluorescence polarisation tracer, and AMP antibody. Plates were incubated for 90 minutes before being read on a PerkinElmer EnVision plate reader in fluorescence polarisation mode. IC.sub.50 values were obtained from the raw readings by calculating percent inhibition (%1) for each reaction relative to controls on the same plate (% I=(ICN)/(CPCN) where CN/CP are the averages of the negative/positive reactions, respectively), then fitting the % I data vs. compound concentration [I] to % I=(A+((BA)/(1+((C/[I])^D)))) where A is the lower asymptote, B is the upper asymptote, C is the IC.sub.50 value, and D is the slope.
(430) Results
(431) TABLE-US-00007 Example IC.sub.50 (uM) 1 1.494 2 2.218 3 3.971 4 0.182 5 0.633 6 1.318 7 0.890 8 0.767 9 0.431 10 0.375 11 0.482 12 0.122 13 0.339 14 1.008 15 1.719 16 0.107 17 4.093 18 0.914 19 1.688 20 0.847 21 0.774 22 0.487 23 0.497 24 0.570 25 0.619 26 0.132 27 0.148 28 1.679 29 0.970 30 2.664 31 1.237 32 0.827 33 0.609 34 1.048 35 0.204 36 0.700 37 0.592 38 2.391 39 0.726 40 0.223 41 1.483 42 0.710 43 0.335 44 2.667 45 0.083 46 0.703 47 0.197 48 0.450 49 2.625 50 0.317 51 0.547 52 0.935 53 0.581 54 0.583 55 0.426 56 1.864 57 0.981 58 0.333 59 0.535 60 1.661 61 2.869 62 0.331 63 0.215 64 0.336 65 0.276 66 0.608 67 3.722 68 1.285 69 0.447 70 1.110 71 0.542 72 17.102 73 2.006 74 1.365 75 0.306 76 2.101 77 0.901 78 0.633 79 0.680 80 0.687 81 2.654 82 2.390 83 1.111 84 0.866 85 0.151 86 0.151 87 0.355 88 0.477 89 1.345 90 0.148 91 0.820 92 0.279 93 2.136 94 1.020 95 2.820 96 0.585 97 0.217 98 0.166 99 0.148 100 0.327 101 0.224 102 1.109 103 0.560 104 2.646 105 1.499 106 8.999 107 1.672
PRMT5 Biomarker Assay
(432) Compounds of the invention may be tested for potency to inhibit the histone H4 Arginine 3 dimethylation mark in the following assay:
(433) The cell line TE11 was seeded at a density of 12,000 cells per well in 96 well tissue culture plates in DME medium and 10% foetal bovine serum, and allowed to adhere overnight under standard culture conditions (37 C., 5% CO.sub.2). Compound dilutions prepared in DMSO were added to the medium, with negative control wells reserved for treatment with DMSO only and positive controls receiving a potent PRMT5 inhibitor. The concentration of the inhibitor had been previously determined to give maximum inhibition of the methylation. After incubation for 72 hours, cells were washed twice in ice-cold PBS, lysed in lysis buffer (20 mM Tris pH 7.4, 135 mM NaCl, 1.5 mM MgCl.sub.2, 1 mM EGTA, 10% glycerol and 1% Triton-X100), centrifuged at 15,000g and the supernatants collected for subsequent analysis. The methylation level was determined using the EpiQuik Global Di-Methyl Histone H4R3 Quantification ELISA Kit (Epigentek, Farmingdale, N.Y.) as per the manufacturer's recommendations; in parallel the total protein amount in the lysate was quantified using a Lowry protein assay. The methylation level was corrected for the total protein amount of each sample, normalised to the controls, and the data fitted against a four-parameter logistic model to determine the 50% inhibitory concentration (IC.sub.50).
(434) Results
(435) TABLE-US-00008 Example IC.sub.50 (uM) 4 0.127 9 0.645 16 1.826 40 0.731 45 1.212
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