4-substitued cytisine analogues

Abstract

Disclosed are novel analogs of cytisine, a process for their preparation, pharmaceutical compositions containing them, and their use in the prevention of or treatment of CNS disorders including addictive disorders.

Claims

1. An enantiomerically pure compound of formula (I): ##STR00162## or a pharmaceutically acceptable salt, solvate and/or ester thereof, wherein: R.sup.1 is hydroxyl; halogen; alkyl; alkenyl; alkynyl; alkoxy; aryl; —NR.sup.5R.sup.6, wherein R.sup.5 and R.sup.6 are each independently selected from hydrogen, aryl, or alkyl; —CH.sub.2—O—CH.sub.2—R.sup.7, wherein R.sup.7 is an aryl; —CN; —COOR.sup.8, wherein R.sup.8 is hydrogen, or alkyl; —NH(C═O)R.sup.9, wherein R.sup.9 is an aryl or alkyl; —CH.sub.2N.sup.10R.sup.11, wherein R.sup.10 and R.sup.11 are each independently selected from hydrogen, a protecting group, or alkyl; an amino acid or ester thereof; acyl chloride; a protecting group; or cytisinyl; R.sup.2 is hydrogen, halogen, or haloalkyl; R.sup.3 is hydrogen; and R.sup.4 is hydrogen or a protecting group, wherein the protecting group is selected from the group consisting of tert-butyloxycarbonyl (Boc), formyl, acetyl (Ac), succinyl (Suc), methoxysuccinyl (MeOSuc), benzyloxycarbonyl (Cbz), fluorenylmethoxycarbonyl (Fmoc), (pinacolato)borane (BPin), and (catecholato)borane (BCat), provided that, when R.sup.2, R.sup.3, and R.sup.4 are hydrogen, R.sup.1 is not methyl, ethyl, bromine, fluorine, chlorine, vinyl, —CH.sub.2OH, 4-F—C.sub.6H.sub.4, butyl-C.sub.6H.sub.4, cyclohexylmethyl, phenyl, allyl ether, propyloxymethyl, CH.sub.2—C.sub.6H.sub.4—CF.sub.3, CH.sub.2—C.sub.6H.sub.4—F, CH.sub.2—O—CH.sub.2—CH.sub.2—CH.sub.3, CH.sub.2—O—CH.sub.2—C.sub.6Hn, CH.sub.2—O—CH.sub.2—C.sub.6H.sub.5, CH.sub.2—O—CH.sub.2—C.sub.6H.sub.4—CF.sub.3, or CH.sub.2—O—CH.sub.2-C.sub.6H.sub.4—F, and provided that, when R.sup.2 and R.sup.3 are hydrogen and R.sup.4 is BOC, R.sup.1 is not methyl, or —CH.sub.2OH.

2. The compound of claim 1, wherein R.sup.1 is an alkyl and the alkyl is a substituted alkyl.

3. The compound of claim 1, wherein R.sup.2 and R.sup.3 are hydrogen.

4. The compound of claim 1, wherein R.sup.4 is a protecting group.

5. An enantiomerically pure compound selected from the group consisting of: (−) 4-carboxymethycytisine; (−) 4-(carboxyamido)cytisine; (+) 4-aminocytisine; (+) 4-(N-acetylamino)cytisine; and (+) 4-Tolylcytisine.

6. The compound of claim 1, wherein the compound is present in a pharmaceutical composition comprising a pharmaceutically acceptable excipient.

7. A method of preventing or treating addiction in a subject, comprising administering a therapeutically effective amount of a compound of claim 1 to a subject in need thereof.

8. A process for preparing a 4-substituted cytisine analog, comprising i) providing a compound of Formula IIa ##STR00163## wherein R.sup.2 is hydrogen, halogen, or haloalkyl, R.sup.3 is hydrogen, and R.sup.4 is hydrogen or a protecting group, the protecting group selected from the group consisting of tert-butyloxycarbonyl (Boc), formyl, acetyl (Ac), succinyl (Suc), methoxysuccinyl (MeOSuc), benzyloxycarbonyl (Cbz), fluorenylmethoxycarbonyl (Fmoc), (pinacolato)borane (BPin), and (catecholato)borane (BCat); ii) producing a compound of Formula IIb ##STR00164## wherein R.sup.2, R.sup.3 and R.sup.4 are as defined above, and BComp is a borylated complex, by contacting the compound of Formula IIa with a borylating agent; and iii) replacing BComp with R.sup.1 to produce and enantiomerically pure compound of formula (I) of claim 1.

9. The process of claim 8, wherein the compound of Formula IIa provided in step i) comprises a hydrogen atom at the R.sup.4 position, that step further comprising the substitution of the hydrogen atom at the R.sup.4 position with a protecting group.

10. The process of claim 9, wherein the protecting group is Boc.

11. The process of claim 9, wherein the compound of Formula IIa is cytisine.

12. The process of claim 8, wherein the borylating agent is selected from one having the formula (RO).sub.2—B—B—(OR).sub.2 or HB(OR).sub.2, and B.sub.2Pin.sub.2 or B.sub.2Cat.sub.2.

13. The process of claim 8, wherein the molar ratio of borylating agent:starting material of Formula IIa is at least about 0.5:1, at least about 0.75:1, at least about 1:1, at least about 1.5:1 or at least about 2:1.

14. The process of claim 8, wherein the reaction in step ii) is carried out in the presence of a transition metal catalyst comprising iridium, palladium, zinc, nickel and/or rhodium.

15. The process of claim 8, wherein the reaction in step ii) is carried out in a solvent selected from an ester solvent, an ether solvent, a ketone solvent, a sulfoxide solvent, an aromatic solvent, a fluorinated aromatic solvent, an alkane solvent or mixtures thereof.

16. The process of claim 8, wherein step ii) is carried out in the presence of a ligand selected from: tetramethyl-1,10-phenanthroline (Me4phen), di-tert-butyl-2,2′-bipyridyl (dtbpy), 2,2′-bipyridine (bpy), 1,1′-bis(diphenylphosphino)ferrocene (dppf), bis(2-di-tert-butylphosphinophenyl)ether, 1,3-bis(diphenylphosphino)propane, (dppp) 1,2-bis(diphenylphosphino)ethane (dppe), hexamethylbenzene (C.sub.6Me6), xantphos or 1,2-bis(dimethylphosphino)ethane (dmpe); phenanthroline (phen), dimethylphenanthroline (me2phen) tetramethyl-1,10-phenanthroline (me4phen), bathophenanthroline (bathophen), di-tert-butyl-2,2′-bipyridyl (dtbpy), 2,2′-bipyridine (bpy), dimethoxy-2,2′-bipyridyl (MeO-bpy), 1,1′-bis(diphenylphosphino)ferrocene (dppf), bis(2-di-tert-butylphosphinophenyl)ether, 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)ethane (dppe), hexamethylbenzene (C.sub.6Me6), neocuproine, xantphos, 1,2-bis(dimethylphosphino)ethane (dmpe); or one of: ##STR00165##

17. The process of claim 16, wherein the molar ratio of borylating starting material of Formula IIa is less than about 2:1, less than about 1.5:1, less than about 1:1, less than about 0.75:1, less than about 0.5:1, less than about 0.1:1, less than about 0.05:1 to at least about 0.001:1.

18. The process of claim 8, wherein the borylation in step ii) is carried out at a temperature of about 50° C. to about 100° C.

19. The process of claim 8, wherein prior to the commencement of step iii) the compound of Formula IIb is not isolated from the product mixture formed in step ii) and/or no purification step is carried out between steps ii) and iii).

20. The process of claim 8, wherein step iii) is commenced in the same reaction zone in which step ii) was carried out.

21. The process of claim 8, wherein, in step iii) BComp is replaced with a first intermediate R.sup.1 substituent.

22. The process of claim 21, wherein the first intermediate substituent is replaced with a second intermediate R.sup.1 substituent, or with a substituent R.sup.1 to provide the compound of Formula I; or the first intermediate substituent is replaced with a second intermediate R.sup.1 substituent and the second intermediate substituent is replaced with a third intermediate R.sup.1 substituent, or with a substituent R.sup.1 to provide the compound of Formula I.

23. The process of claim 21, wherein the first, second or third intermediate R.sup.1 substituents are independently selected from bromo, chloro, iodo, benzyloxypyridine, alkyl ester, alkenyl, alkynyl, trimethylsilylacetylene, 1,2,3-triazol-1-ylmethyl pivalate, cyano, aminomethyl, N-Boc-aminomethyl or (benzyloxy)carbonyl)piperazin-1-yl.

24. The process of claim 8, wherein the compound of Formula IIb or Formula I comprises a protecting group at the R.sup.4 position, the process further comprising deprotecting the R.sup.4 group of the compound of Formula IIb or Formula I and deprotecting the R.sup.4 group of the compound of Formula IIb or Formula I takes place after the completion of step ii), before the commencement of step iii), during step iii) or after the completion of step iii).

25. The compound of claim 2, wherein the substituted alkyl is a halogenated substituted alkyl.

26. The compound of claim 1, wherein R.sup.1 is an aryl and the aryl is substituted with a heteroaryl.

27. The compound of claim 26, wherein the heteroaryl is a substituted heteroaryl.

28. The compound of claim 1, wherein R.sup.1 is an aryl and the aryl is a substituted aryl.

29. The compound of claim 1, wherein R.sup.1 is an alkyl and the alkyl is substituted with a cycloalkyl.

30. The compound of claim 1, wherein R.sup.1 is an alkyl and the alkyl is substituted with a heterocycloalkyl.

31. The compound of claim 1, wherein R.sup.1 is an alkynyl and the alkynyl is a substituted alkynyl.

32. The compound of claim 1, wherein R.sup.1 is an alkenyl and the alkenyl is a substituted alkenyl.

33. The compound of claim 1, wherein R.sup.1 is an alkoxy and the alkoxy is selected from the group consisting of methoxy, ethoxy, propoxy, benzyloxy, and trifluoromethylbenzyloxy.

34. The compound of claim 1, wherein the amino acid or ester thereof is selected from the group consisting of alanine, arginine, asparagine, aspartate, cysteine, glutamine, glutamate, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, and tyrosine.

35. The compound of claim 1, wherein R.sup.1 is NR.sup.5R.sup.6, one of R.sup.5 or R.sup.6 is a hydrogen, and one of R.sup.5 or R.sup.6 is an alkyl, wherein the alkyl is selected from the group consisting of a methyl, ethyl, or isopropyl.

36. The compound of claim 34, wherein the amino acid or derivative thereof is lysine.

37. The compound of claim 30, wherein the heterocycloalkyl is morpholinyl or piperazyl.

38. The compound of claim 29, wherein the substituted aryl is a tolyl.

39. The compound of claim 1, wherein R.sup.1 is an alkynyl and the alkynyl is trimethylsilyl acetylene, phenylacetylene, or acetylene.

40. The compound of claim 1, wherein R.sup.1 is an alkenyl and the alkenyl is propenoate methyl ester or phenylethenyl.

Description

PREPARATIONS AND EXAMPLES

(1) Extraction of (−)-Cytisine from Laburnum anagyroides Seeds

(2) As explained above, the process of the present invention advantageously commences from cytisine, a naturally occurring compounds which can be isolated from laburnum trees. While cytisine is commercially available, and those skilled in the art will be familiar with processes for extracting cytisine from natural sources, the following process is provided for completeness.

(3) Powdered Laburnum anagyroides seeds (332 g), DCM (465 mL), MeOH (135 mL) and NH.sub.4OH (50 mL, 35% aq. sol.) were stirred vigorously for 3 days at r.t. with a mechanic stirrer (400 rpm). The mixture was filtered and the solids were washed with DCM (4×200 mL) until the filtrate was colourless. The filtrate was acidified with 3M HCl (330 mL) to pH 1 and the mixture was stirred for 2 h (350 rpm). The two layers were separated and the aqueous layer was slowly basified to pH 9-10 with NH.sub.4OH (70 mL, 35% aq. sol.). The mixture was stirred for 2 h, and extracted with DCM (10×70 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo yielding cytisine (4.76 g) as brown-yellow solid. Recrystallisation from toluene (5 mL) yielded (−)-cytisine (4.27 g, 1.3%) as a solid.

(4) Addition of Protecting Group—N-Boc cytisine (56)

(5) ##STR00010##

(6) To a solution of (−)-cytisine (6.41 g, 33.7 mmol) and (Boc).sub.2O (9.3 mL, 40.4 mmol) in THF (135 mL) and water (70 mL) was added an aqueous solution of Na.sub.2CO.sub.3 (4.28 g, 40.4 mmol, 1 M). The mixture was stirred for 3 days, and then diluted with EtOAc (200 mL) and brine (70 mL). The aqueous layer was extracted with EtOAc (3×150 mL) and the combined organic layers were washed with brine (150 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (3% MeOH)] to give 56 (9.10 g, 93%) as a colourless solid.

(7) R.sub.f: 0.28 [DCM/MeOH (5% MeOH)]; mp: 154-155° C. (lit: 156-157° C.); .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.26 (dd, 1H, J=9.0, 7.0 Hz, C4-H), 6.41 (d, 1H, J=9.0 Hz, C3-H), 6.04 (br s, 1H, C5-H), 4.40-4.08 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.81 (dd, 1H, J=15.5, 6.5 Hz, C7-H.sub.b), 3.12-2.91 (m, 3H, C11-H, C12-H, C10-H), 2.40 (br s, 1H, C8-H), 2.00-1.90 (m, 2H, C9-H), 1.31-1.20 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.3 (CO), 154.4/154.3 (C6, rotamers), 149.3/148.7 (CO Boc, rotamers), 138.9/138.4 (C4, rotamers), 117.0 (C3), 105.6/104.9 (C5, rotamers), 80.2/79.6 (q Boc, rotamers), 51.5/50.5/49.2 (C11, C12, rotamers), 48.8 (C7), 34.8 (C10), 28.0 (3C, Boc), 27.5 (C8), 26.1 (C9). The spectroscopic properties of this compound were consistent with the data available in literature.

(8) Removal of Protecting Group

(9) As will be exemplified below, a wide range of 4-substituted cytisine derivatives can be prepared according to the process of the present invention. For such compounds, it may be desirable to remove the Boc protecting group. In the examples below, the Boc protecting group where present on the 4-substituted cytisine analogs was removed by one of the two following processes

(10) General Procedure A

(11) The cytisine derivative was dissolved in a solution 0.5 M HCl in MeOH (concentration of the substrate 0.1 M) and the reaction mixture was stirred for 72 h at r.t. Then, the solvent was removed in vacuo. The residue was dissolved in the minimum amount of MeOH and 10 times the MeOH volume of acetone was added slowly. The solution was stirred for 2 h. After, the precipitate was collected by filtration and washed with cold acetone.

(12) General Procedure B

(13) The cytisine derivative was dissolved in a solution 4.0 M HCl in dioxane (concentration of the substrate 0.1 M) and the reaction mixture was stirred for 72 h at r.t. Then, the solvent was removed in vacuo. The residue was dissolved in the minimum amount of MeOH and 10 times the MeOH volume of acetone was added slowly. The solution was stirred for 2 h. After, the precipitate was collected by filtration and washed with cold acetone.

Example 1—N-Boc 4-Bpincytisine (58)

(14) ##STR00011##

(15) A Schlenk tube was charged with N-Boc-cytisine, 56 (290 mg, 1.00 mmol), bis-(iridium-cycloctadienyl-methoxide) (6.6 mg, 0.01 eq.), 4,4′-2,2′-di-tert-butylbispyridine (5.4 mg, 0.02 eq.) and bis(pinacolato)-diborane (177 mg, 0.7 eq.). The Schlenk tube was placed under vacuum and backfilled with nitrogen for three times, THF (1.4 mL) was added and the mixture was heated at 80° C. for 24 h. The mixture was cooled to r.t. and concentrated in vacuo. Although purification (see below) is possible, this was not essential; the crude reaction mixture was used in a number of subsequent conversion steps without further purification.

(16) The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (5% MeOH)] to give 58 (180 mg, 43%; unstable compound on silica, only pure fractions collected; full conversion by .sup.1H-NMR) as a pale orange foam.

(17) R.sub.f: 0.23 [DCM/MeOH (5% MeOH)]; FTIR v.sub.max/cm.sup.−1 (neat): 3433, 2977, 1688, 1657, 1563, 1423; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.85 (s, 1H, C3-H), 6.31 (s, 1H, C5-H), 4.34-4.10 (m, 3H, C7-H.sub.a, C12-H, C11-H), 3.80 (dd, 1H, J=15.5, 6.5 Hz, C7-H.sub.b), 3.07-2.91 (m, 3H, C10-H, C11-H, C12-H), 2.41 (s, 1H, C10-H), 1.95-1.88 (m, 2H, C9-H), 1.41-1.09 (m, 23H, 12×Bpin-H, 9×Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.9 (CO), 154.6/154.3 (C6, rotamers), 147.9/147.5 (CO Boc, rotamers), 124.4 (C3), 109.3/108.8 (C5, rotamers), 84.4 (q Boc), 82.6/80.3, 79.7/75.0 (2C, q Bpin, rotamers), 51.7/50.6/50.3/49.2 (C11, C12, rotamers), 48.9 (C7), 34.7 (C10), 28.0 (4C, Bpin), 27.5 (C8), 26.1 (C9), 24.8/24.6 (3C, Boc, rotamers), C4 non-detected; .sup.11B NMR (96.4 MHz, CDCl.sub.3, δ.sub.B): 28.94 (br s); HRMS (ESI.sup.+): calculated for C.sub.22H.sub.33BN.sub.2NaO.sub.5 [M+Na].sup.+: 439.2379, found: 439.2373.

Example 2a—N-Boc4-Hydroxycytisine (66)

(18) ##STR00012##

(19) N-Boc-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine discussed above in Example 1 in a 1.0 mmol scale.

(20) The borylation reaction mixture was cooled to 0° C. and dissolved in THF (8.6 mL). NaOH 3 M (1.0 mL, 3.0 mmol) was added followed by a slow addition of 30% aqueous H.sub.2O.sub.2 (1.0 mL) over 5 min. The mixture was stirred at 0° C. for 30 min and then stirred under air at r.t. overnight. The mixture was diluted with water (3 mL) and the aqueous layer was washed with DCM (3×5 mL). The aqueous layer was acidified with 3 M HCl to pH 4-5 and extracted with DCM (5×5 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (5% MeOH)] to give 66 (240 mg, 79%) as an off-white solid.

(21) R.sub.f: 0.13 [DCM/MeOH (5% MeOH)]; mp: >200° C., colourless powder; FTIR v.sub.max/cm.sup.−1 (neat): 2864, 1673, 1652, 1535, 1423; .sup.1H NMR (400 MHz, DMSO-d.sub.6, δ.sub.H): 10.27 (s, 1H, OH), 5.76 (s, 1H, C3-H), 5.45 (s, 1H, C5-H), 4.12-3.78 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.51 (dd, 1H, J=15.0, 6.5 Hz, C7-H), 3.16-2.93 (m, 3H, C10-H, C11-H, C12-H), 2.29 (br s, 1H, C8-H), 1.84 (s, 2H, C9-H), 1.23-1.14 (m, 9H, Boc); .sup.13C NMR (100 MHz, DMSO-d.sub.6, δ.sub.C): 166.0 (C4), 164.2 (CO), 154.1 (C6), 150.4 (CO Boc), 98.8/98.7 (C3, rotamers), 96.3 (C5), 79.3/78.8 (q Boc, rotamers), 51.7/50.6/50.3/49.3 (C11, C12, rotamers), 48.3 (C7), 34.5 (C10), 28.1 (3C, Boc), 27.4 (C8), 25.9 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.23N.sub.2O.sub.4: 307.1652, found [M+H].sup.+: 307.1650, C.sub.16H.sub.22N.sub.2NaO.sub.4: 329.1472, found [M+Na].sup.+: 329.1469.

Example 2b—(+)4-Hydroxycytisine hydrochloride salt (67)

(22) ##STR00013##

(23) Following the general procedure A, alcohol 66 (0.79 mmol) gave alcohol 67 (184 mg, 96%) as an off-white solid.

(24) mp: >200° C., colourless powder; [α].sub.D.sup.25=+3.0 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3444, 2934, 2597, 1641, 1589; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.33 (d, 1H, C3-H, J=2.0 Hz), 6.02 (d, 1H, C5-H, J=2.0 Hz), 4.07 (d, 1H, C7-H.sub.a, J=15.5 Hz), 3.93 (dd, 1H, J=15.5, 6.5 Hz, C7-H.sub.b), 3.40-3.24 (m, 5H, C10-H, C11-H, C12-H), 2.69 (br s, 1H, C8-H), 2.03-1.93 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 168.4 (CO), 164.2 (C6), 149.3 (C4), 105.3 (C3), 97.2 (C5), 49.1 (C11 or C12), 49.0 (C7), 48.1 (C11 or C12), 31.5 (C10), 24.6 (C8), 22.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.15N.sub.2O.sub.2: 207.1128, found [M+H—HCl].sup.+: 207.1136.

Example 3a—N-Boc4-Methoxycytisine (68)

(25) ##STR00014##

(26) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine discussed above in Example 1 in a 0.50 mmol.

(27) A freshly prepared solution of CuSO.sub.4.Math.5H.sub.2O (37 mg, 0.15 mmol), KOH (84 mg, 1.50 mmol) and molecular sieves 4 Å (300 mg) in methanol (5 mL) was stirred for 5 h under nitrogen atmosphere, and then transferred over the crude of the borylation reaction using a syringe. The reaction mixture was stirred at reflux for 18 h under an oxygen atmosphere. The reaction was diluted with 10 mL of methanol, filtered through a celite pad and the solvent was removed under vacuum. The crude was distributed between ammonia solution (15 mL, 15% aq. sol.) and DCM (15 mL), and the aqueous phase was extracted with DCM (4×15 mL). The organic phases were combined, dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [DCM/MeOH, (2% MeOH)] afforded 69 (130 mg, 81%) as a colourless solid.

(28) mp: 170-171° C., colourless needles (toluene); R.sub.f: 0.41 [DCM/MeOH (6% MeOH)]; FTIR v.sub.max/cm.sup.−1 (neat): 2971, 1673, 1646, 1427; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H, 52.0° C.): 5.85 (s, 1H, C3-H), 5.79 (s, 1H, C5-H), 4.39-4.07 (m, 3H, C11-H, C12-H, C7-H), 3.82-3.74 (m, 1H, C7-H), 3.73 (s, 3H, OMe), 3.13-2.85 (m, 3H, C11-H, C12-H, C10-H), 2.38 (s, 1H, C8-H), 1.93 (m, 2H, C9-H), 1.41-1.18 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C, 52.0° C.): 167.4 (C4), 164.9 (CO), 154.4 (C6), 148.7 (CO Boc), 99.5 (C5), 94.8 (C3), 80.1 (q Boc), 55.1 (OMe), 50.6 (C11, C12), 48.4 (C7), 34.9 (C10), 28.1 (3C, Boc), 27.6 (C8), 26.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.25N.sub.2O.sub.4: 321.1809, found [M+H].sup.+: 321.1800; Anal. Calc. for C.sub.17H.sub.25N.sub.2O.sub.4: C, 63.73, H, 7.55, N, 8.74. Found C, 64.15, H, 7.49, N, 8.77.

Example 3b—(−)4-Methoxycytisine (69)

(29) ##STR00015##

(30) To a solution of ether 68 (130 mg, 0.42 mmol) in DCM (4 mL, 0.1 M) was added TFA (0.3 mL, 10 eq.) at once, and the reaction mixture was stirred at r.t. for 18 h. Water (10 mL) was added and the aqueous phase was washed with DCM (3×10 mL). The aqueous phase was basified with ammonia (10 mL, 15% aq. sol.) and extracted with DCM (3×10 mL). The organic phases were combined, dried over MgSO.sub.4, filtered and concentrated, yielding 69 (76 mg, 85%) as a colourless solid.

(31) mp: >200° C., colourless powder; [α].sub.D.sup.24=−42 [c 1.0, EtOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2889, 1645, 1580, 1557, 1158; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 5.87 (d, J=3.0 Hz, 1H, C3-H), 5.74 (d, J=3.0 Hz, 1H, C5-H), 4.10 (d, J=15.0 Hz, 1H, C7-H), 3.85 (dd, J=15.0, 6.5 Hz, 1H, C7-H), 3.77 (s, 3H, OMe), 3.14-2.98 (m, 4H, C11-H, C12-H), 2.84 (s, 1H, C10-H), 2.30 (s, 1H, C8-H), 1.96 (s, 2H, C9-H), 1.55 (s, 1H, NH); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 167.4 (CO), 165.1 (C6), 150.6 (C4), 98.6 (C5), 94.5 (C3), 55.2 (OMe), 53.4, 53.0 (C11, C12), 49.2 (C7), 35.7 (C10), 27.7 (C8), 26.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.17N.sub.2O.sub.2: 221.1285, found [M+H].sup.+: 221.1283.

Example 4a—N-Boc4-(N-Benzylamino)cytisine (70)

(32) ##STR00016##

(33) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as detailed in Example 1 above in a 5.00 mmol scale.

(34) In a separate vessel, Cu(OAc).Math.H.sub.2O (300 mg, 1.5 mmol), KF (320 mg, 5.5 mmol), and molecular sieves 4 Å (4 g) were stirred in MeCN (20 mL) for 15-20 min. The crude of the borylation reaction was solubilised in MeCN (5 mL) and the copper solution was added via syringe to the crude reaction, stirring for 10 min. Freshly distilled BnNH.sub.2 (1.1 mL, 10.0 mmol) was added and the reaction mixture was heated at reflux for 18 h under an oxygen atmosphere. The reaction mixture was cooled, filtered through Celite® and concentrated. The crude of the reaction was distributed between ammonia (25 mL, 15% aq. sol.) and DCM (25 mL) and the aqueous phase was extracted with DCM (4×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The crude reaction mixture was purified by flash column chromatography [DCM/MeOH (2% MeOH)] affording 70 (1.70 g, 72%), together with an inseparable impurity, as a colourless solid.

(35) .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 7.35-7.19 (m, 5H, Ar), 5.52 (s, 1H, C3-H), 5.46 (s, 1H, C5-H), 4.66 (s, 1H, NH), 4.38-4.11 (m, 3H, C13-H, C11-H or C12-H); 4.05 (d, J=15.5 Hz, 1H, C7-H), 3.71 (m, 1H, C7-H), 3.17-2.78 (m, 3H, 2×C11-H or C12-H, 1H×C11-H or C12-H), 2.74 (s, 1H, C10-H), 2.31 (s, 1H, C8-H), 1.96-1.80 (m, 2H, C9-H), 1.28 (s, 9H, Boc).

Example 4b—(+)4-(N-Benzylamino)cytisine (71)

(36) ##STR00017##

(37) To a solution of the secondary amine 70 (1.70 g, 4.30 mmol) in DCM (43 mL, 0.1 M) was added TFA (0.4 mL, 10 eq.) and the solution was stirred at r.t. for 16 h. Water was added (20 mL) and the aqueous phase was washed with DCM (3×30 mL). Then, the aqueous phase was basified with ammonia (15 mL, 15% aq. sol.) and extracted with DCM (4×30 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated, yielding 71 (970 mg, 76%) as a colourless solid.

(38) R.sub.f: 0.39 [DCM/MeOH (8% MeOH)]; mp: 208-211° C., (toluene); [α]D.sup.25=+58 [c 0.5, EtOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3266, 2919, 1637, 1559, 1533; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 7.35-7.23 (m, 5H, Ar), 5.52 (s, 1H, C3-H), 5.48 (s, 1H, C5-H), 4.58 (s, 1H, NHPh), 4.26 (s, 1H, CH.sub.2Ph), 4.25 (s, 1H, CH.sub.2Ph), 4.03 (d, J=14.5 Hz, 1H, C7-H), 3.77 (dd, J=6.5, 14.5 Hz, 1H, C7-H), 3.09-2.93 (m, 4H, C11-H C12-H), 2.71 (s, 1H, C10-H), 2.21 (s, 1H, C8-H), 1.90 (s, 2H, C9-H), 2.07-1.71 (s, 1H, NH); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 164.6 (CO), 154.9 (C4), 149.7 (C6), 137.8 (Ar), 128.7 (Ar, 2C), 127.5 (Ar), 127.4 (Ar, 2C), 97.2 (C5), 91.2 (C3), 53.8 (C11), 52.8 (C12), 48.7 (C7), 47.0 (CH.sub.2-Ph), 35.5 (C10), 27.7 (C8), 26.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.22N.sub.3O: 296.1757, found [M+H].sup.+: 296.1766; Anal. Calc. for C.sub.18H.sub.21N.sub.3O: C: 73.19, H: 7.17, N: 14.23; found C: 73.24, H: 7.18, N: 14.35.

Example 5—(−)4-(2,2,2-Trifluoroethyl)cytisine hydrochloride salt (79)

(39) ##STR00018##

(40) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as detailed in Example 1 above in a 1.00 mmol scale.

(41) To the crude borylation reaction mixture, [Pd.sub.2(dba).sub.3] (23 mg, 1 mmol %), Xphos (47 mg, 2.5 mmol %), caesium fluoride (450 mg, 3.0 eq.) and copper (1) chloride anhydrous (99 mg, 1.0 eq.) were added, and the Schlenk tube was placed under vacuum and backfilled with nitrogen for three times. The reaction mixture was dissolved in DMF (4.0 mL, 0.25 M) and 2-iodo-1,1,1-trifluoroethane (0.19 mL, 2.0 eq.) and water (0.14 mL, 8.0 eq.) were added. The reaction mixture was stirred at 65° C. for 18 h. The solvent was removed in vacuo and the reaction crude distributed between EtOAc (15 mL) and water (15 mL). The aqueous phase was extracted with EtOAc (3×15 mL). The organic phases were combined, dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [DCM/MeOH (2% MeOH)] afforded N-Boc-4-(2,2,2-trifluoroethyl)-cytisine (190 mg, 50%) as a colourless solid. The resulting trifluoro-cytisine derivative was deprotected and converted into its HCl salt following the general procedure A yielded ligand 79 (93 mg, 34%) as a colourless solid.

(42) mp: >200° C., colourless powder; [α].sub.D.sup.26=−42 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2723, 1640, 1563, 1467, 1458; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.61-6.55 (m, 2H, C3-H, C5-H), 4.14-3.88 (m, 2H, C7-H), 3.5-3.26 (m, 7H, C10-H, C11-H, C12-H, CH.sub.2—CF.sub.3), 2.75 (s, 1H, C8-H), 2.15-1.95 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.5 (CO), 147.0 (C6), 145.3 (C4), 125.0 (d, J=276 Hz, CF.sub.3), 118.4, 111.4 (C3, C5), 49.4, 48.2 (C11, C12), 48.6 (C7), 38.3 (q, J=30.0 Hz, C14), 31.4 (C10), 24.7 (C8), 22.5 (C9); .sup.19F NMR (376 MHz, D.sub.2O, δ.sub.F): −64.5 (t, 11.0 Hz); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.16F.sub.3N.sub.2O: 273.1209, found [M+H—HCl].sup.+: 273.1220.

Example 6—(−)4-(Perfluorophenyl)cytisine hydrochloride salt (75)

(43) ##STR00019##

(44) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine detailed in Example 1 above in a 1.00 mmol scale.

(45) Bromopentafluorobenzene (0.15 mL, 1.2 eq.), PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 0.05 eq.) and Cs.sub.2CO.sub.3 (410 mg, 2.5 eq.) were added over the crude of the borylation reaction and the reaction mixture was dissolved in THF (5 mL, 0.2 M) and stirred at 80° C. for 18 h. The reaction mixture was diluted with ammonia (25 mL, 15% aq. sol.), and the aqueous phase was extracted with EtOAc (4×25 mL). The combined organic phases were dried over MgSO.sub.4, the solids were filtered off and the solvent was evaporated in vacuo. Purification of the crude reaction mixture by flash column chromatography [DCM/MeOH (1.5% MeOH)] yielded 74 (509 mg, 99%) as a colourless solid. (Contaminated with [PdCl.sub.2(PPh.sub.3).sub.2]).

(46) .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.53 (s, 1H, C3-H), 6.09 (s, 1H, C5-H), 4.49-4.12 (m, 3H, C11-H C12-H C7-H), 3.88 (dd, J=16.5, 6.5 Hz, 1H, C7-H), 3.18-2.96 (m, 3H, C11-H C12-H C8-H), 2.47 (s, 1H, C10-H), 2.02 (m, 2H, C9-H), 1.29 (s, 9H, Boc).

(47) Following the general procedure A, N-Boc protected cytisine derivative 74 (1.1 mmol) gave 4-(perfluorophenyl)-cytisine hydrochloride salt 75 (160 g, 43%) as a colourless solid.

(48) mp: >200° C., colourless powder; [α].sub.D.sup.26=−16 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2977, 2869, 1658, 1536; .sup.1H NMR (500 MHz, MeOH, δ.sub.H): 6.58 (s, 1H, C3-H), 6.43 (s, 1H, C5-H), 4.13 (d, J=15.5 Hz, 1H, C7-H), 4.00 (dd, J=6.0, 15.0 Hz, 1H, C7-H), 3.14-2.99 (m, 5H, C11-H C12-H C10-H), 2.43 (s, 1H, C8-H), 2.07 (m, 2H, C9-H); .sup.13C NMR (125 MHz, MeOH, δ.sub.C): 163.7 (CO), 152.4 (C4), 144.9 (m), 143.1 (m), 142.2 (m), 140.2 (m), 138.8 (m), 136.7 (m) (6C, Ar), 138.5 (C6), 117.0 (C3), 107.4 (C5), 52.6, 51.6 (C11, C12), 49.8 (C7), 35.2 (C10), 27.4 (C8), 25.2 (C9); .sup.19F NMR (376 MHz, D.sub.2O, δ.sub.F): −140.7, −141.3, −152.9, −160.8, −161.1; HRMS (ESI.sup.+): calculated for C.sub.17H.sub.14F.sub.5N.sub.2O: 357.1021, found [M+H.sup.+—HCl].sup.+: 357.1017.

Example 7a—N-Boc4-(2-Pyridinyl)cytisine (100)

(49) ##STR00020##

(50) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as detailed above in Example 1 in a 1.00 mmol scale.

(51) Anhydrous Cs.sub.2CO.sub.3 (814 mg, 2.5 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) were added over the borylation reaction crude mixture. Dry THF (10 mL) was added followed by 2-bromopyridine (115 μL, 1.2 mmol). The mixture was stirred at 80° C. for 48 h. The reaction was cooled to r.t., diluted with EtOAc (50 mL) and filtered through Celite.® The organic layer was washed with water (10 mL), brine (10 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (4% MeOH)+0.1% ammonia (15% aq. sol.)] to give 100 (205 mg, 56%) as a yellow oil. The product was used in the next step without any further purification.

(52) R.sub.f: 0.17 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 8.65 (d, 1H, J=2.0 Hz, C15-H), 7.75-7.68 (m, 2H, C17-H, C18-H), 7.29-7.26 (m, 1H, C16-H), 6.92 (s, 1H, C3-H), 6.86 (s, 1H, C5-H), 4.37-4.17 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.84 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.11-2.96 (m, 3H, C10-H, C11-H, C12-H), 2.42 (s, 1H, C8-H), 2.01-1.92 (m, 2H, C9-H), 1.30-1.13 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.7 (CO), 154.5 (CO Boc), 154.2 (C6), 149.6 (C4), 148.8 (C13), 145.4 (C16), 136.9 (C17), 123.8 (C16), 121.1 (C18), 113.8 (C3), 104.4/103.9 (C5, rotamers), 80.3/79.8 (q Boc, rotamers), 51.6/50.6/50.3/49.3 (C11, C12, rotamers), 48.9 (C7), 35.1 (C10), 27.5 (C8), 26.2 (C9), 24.8 (3C, Boc); HRMS (ESI.sup.+): calculated for C.sub.21H.sub.26N.sub.3O.sub.3 [M+H].sup.+: 368.1969, found: 368.1965; calculated for C.sub.21H.sub.25N.sub.3NaO.sub.3: 390.1788, found [M+Na].sup.+: 390.1784.

Example 7b—(−)4-(2-Pyridinyl)cytisine dihydrochloride salt (101)

(53) ##STR00021##

(54) Following the general procedure A for the deprotection of cytisine, N-Boc-4-(2-Pyridinyl)-cytisine 100 (0.55 mmol) gave 101 (99.2 mg, 63%) as a colourless solid.

(55) mp: >200° C., colourless powder; [α].sub.D.sup.24=−12 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3471, 2750, 1658, 1572; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 8.71-8.70 (m, 1H, C16-H), 8.53-8.49 (m, 1H, C18-H), 8.16 (d, 1H, J=8.0 Hz, C19-H), 7.97-7.94 (m, 1H, C17-H), 6.89 (d, 1H, J=2.0 Hz, C3-H), 6.84 (s, 1H, J=2.0 Hz, C5-H), 4.11 (d, 1H, J=16.0 Hz, C7-H.sub.a), 3.98 (dd, 1H, J=6.5, 16.0 Hz, C7-H.sub.b), 3.52 (br s, 1H, C10-H), 3.45-3.30 (m, 4H, C11-H, C12-H), 2.77 (br s, 1H, C10-H), 2.10-2.00 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.3 (CO), 149.3 (C6), 148.7 (C4), 146.9 (Ar py), 143.3 (Ar py), 142.7 (Ar py), 127.3 (Ar py), 126.2 (Ar py), 116.4 (C3), 107.0 (C5), 49.3, 49.0 (C11, C12), 48.2 (C7), 31.8 (C8), 24.7 (C10), 22.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.18N.sub.3O: 268.1444, found [M+H.sup.+-2HCl].sup.+: 268.1444.

Example 8—(−)4-(3-Pyridinyl)cytisine dihydrochloride salt (104)

(56) ##STR00022##

(57) A Schlenk tube was charged with N-Boc-4-bromo-cytisine 61 (370 mg, 1.0 mmol), [Pd.sub.2(dba).sub.3] (9.0 mg, 1 mmol %), tricyclohexylphosphine (7.0 mg, 2.4 mmol %) and 3-pyridinylboronic acid (140 mg, 1.1 eq.), and placed under vacuum and backfilled with nitrogen three times. The mixture was dissolved in dioxane (2.6 mL, 0.4 M) and a solution of tripotassium phosphate in water (360 g, 1.7 eq., 1.3 M) was added dropwise with a syringe over 10 min. The reaction mixture was heated at 100° C. for 18 h. The solution was filtered through celite and the solvent was removed in vacuo. Ammonia solution (5 mL, 15% aq. sol.) was added and the aqueous phase was extracted with DCM (4×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The resulting N-Boc-4-(3-pyridinyl)-cytisine derivative was deprotected and converted into the HCl salt following the general procedure A yielding 104 (210 mg, 78%) as a colourless solid.

(58) mp: >200° C., colourless powder; [α].sub.D.sup.24=−11 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2926, 2528, 2072, 1650, 1539; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 9.39 (s, 1H, Ar Py), 9.07 (s, 1H, Ar Py), 9.01 (s, 1H, Ar Py), 8.27 (s, 1H, Ar Py), 7.10 (s, 1H, C3-H), 7.06 (s, 1H, C5-H), 4.35 (d, 1H, J=15.5 Hz, C7-H), 4.14 (dd, 1H, J=15.5, 6.0 Hz, C7-H), 3.69-3.53 (m, 5H, C11-H C12-H C10-H), 2.89 (s, 1H, C8-H), 2.28 (d, J=13.5 Hz, 1H, C9-H), 2.17 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (125 MHz, MeOD, δ.sub.C): 163.6 (CO), 148.9 (C6), 145.3 (q Py), 144.9 (Py), 141.7 (Py), 140.2 (Py), 136.7 (C4), 127.7 (Py), 115.0 (C5), 107.1 (C3), 49.1, 48.5 (C11, C12), 48.9 (C7), 32.0 (C10), 25.2 (C8), 22.7 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.18N.sub.3O: 268.1444, found [M+H-2HCl].sup.+: 268.1444.

Example 9a—(−)N-Boc4-(4-Pyridinyl)cytisine (102)

(59) ##STR00023##

(60) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine detailed in Example 1 above in a 1.00 mmol scale.

(61) Anhydrous Cs.sub.2CO.sub.3 (814 mg, 2.5 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) were added over the crude borylation reaction mixture. Dry THF (10 mL) was added followed by 4-iodopyridine (246 mg, 1.2 mmol). The mixture was stirred at 80° C. for 48 h. The mixture was cooled to r.t., diluted with EtOAC (50 mL) and filtered through Celite.® The organic layer was washed with brine (10 mL), dried on Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude mixture was purified by flash column chromatography on silica gel [DCM/MeOH (5% MeOH)+0.1% ammonia (15% aq. sol.) to give 102 (312 mg, 85%) as an orange oil. The product was used in the next step without any further purification.

(62) R.sub.f: 0.39 [DCM/MeOH (10% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 8.63 (d, 2H, J=6.0 Hz, C15-H, C17-H), 7.41 (d, 2H, J=6.0 Hz, C14-H, C18-H), 6.66 (s, 1H, C3-H), 6.28 (s, 1H, C5-H), 4.38-4.15 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.82 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.06 (br s, 3H, C10-H, C11-H, C12-H), 2.42 (br s, 1H, C8-H), 2.02-1.93 (m, 2H, C9-H), 1.30-1.13 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.3 (CO), 154.5/154.2 (CO Boc, rotamers), 150.4 (C15, C17), 149.6 (C6), 148.0/147.8 (C4, rotamers), 145.2 (C13), 121.1 (C14, C18), 114.4 (C3), 104.3/103.5 (C5, rotamers), 80.5/79.8 (q Boc, rotamers), 51.7/50.6/50.3/49.3 (C11, C12, rotamers), 49.0 (C7), 35.1 (C10), 27.4 (C8), 26.1 (C9), 24.8 (3C, Boc); HRMS (ESI.sup.+): calculated for C.sub.21H.sub.26N.sub.3O.sub.3: 368.1969, found [M+H].sup.+: 368.1970, calculated for C.sub.21H.sub.25N.sub.3NaO.sub.3: 390.1788, found [M+Na].sup.+: 390.1791.

Example 9b—(−)4-(4-Pyridinyl)cytisine dihydrochloride salt (103)

(63) ##STR00024##

(64) Following the general procedure A, N-Boc4-(4-pyridinyl)cytisine 102 (0.85 mmol) gave 103 (122 mg, 48%) as a pale-orange solid.

(65) mp: >200° C., colourless powder; [α].sub.D.sup.24=−12 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2590, 1653 (w), 1631, 1579, 1545; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 8.75 (d, 2H, J=6.5 Hz, C14-H, C18-H), 8.20 (d, 2H, J=6.5 Hz, C15-H, C17-H), 6.90 (d, 1H, J=2.0 Hz, C3-H), 6.86 (s, 1H, J=2.0 Hz, C5-H), 4.10 (d, 1H, J=16.0 Hz, C7-H.sub.a), 3.97 (dd, 1H, J=6.5, 16.0 Hz, C7-H.sub.b), 3.51 (s, 1H, C10-H), 3.45-3.28 (m, 4H, C11-H, C12-H), 2.76 (br s, 1H, C8-H), 2.09-1.99 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.5 (CO), 154.3 (C4), 148.7 (C6), 146.7 (C13), 141.6 (2C, C15, C17), 125.2 (2C, C14, C17), 116.3 (C3), 107.4 (C5), 49.4 (C11 or C12), 48.9 (C7), 48.2 (C11 or C12), 31.8 (C10), 24.7 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.18N.sub.3O: 268.1444, found [M+H].sup.+: 268.1453.

Example 10a—N-Boc4-(4-(2-Benzyloxy)pyridine)cytisine 105

(66) ##STR00025##

(67) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine detailed above in Example 1 in a 1.00 mmol scale.

(68) Anhydrous Cs.sub.2CO.sub.3 (814 mg, 2.5 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) were added over the crude borylation reaction mixture. Dry THF (5.0 mL) was added followed by a solution of 4-bromo-2-benzyloxypyridine (316 mg, 1.2 mmol) in dry THF (5.0 mL). The mixture was stirred at 80° C. for 48 h. The solution was cooled to r.t., diluted with EtOAc (50 mL) and filtered through Celite®. The organic layer was washed with water (10 mL), brine (10 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (4% MeOH)+0.1% ammonia (15% aq. sol.)] to give 105 (485 mg, 99%) with few impurities as a pale yellow oil. The product was used in the next step without any further purification.

(69) R.sub.f: 0.23 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 8.22 (d, 1H, J=5.0 Hz, C16-H), 7.46 (d, 2H, J=7.0 Hz, C20-H, C24-H), 7.39-7.29 (m, 3H, C21-H, C22-H, C23-H), 7.04 (d, 1H, J=5.0 Hz, C17-H), 6.96 (s, 1H, C14-H), 6.67 (s, 1H, C3-H), 6.27 (s, 1H, C5-H), 5.41 (s, 2H, C18-H), 4.40-4.18 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.84 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.05 (s, 3H, C10-H, C11-H, C12-H), 2.44 (s, 1H, C8-H), 2.03-1.94 (m, 2H, C9-H), 1.33-1.17 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 164.4 (C15), 163.4 (CO), 154.7/154.4 (CO Boc, rotamers), 150.0, 149.5 (C6, C4), 148.3, 147.7 (C13, C16), 137.2 (C19), 128.6, 128.1, 128.0 (5C, C20, C21, C22, C23, C24), 114.9, 114.5 (C3, C17), 108.9/108.7 (C14, rotamers), 104.4/103.7 (C5, rotamers), 80.5/79.9 (q Boc, rotamers), 68.0 (C18), 51.8/50.7/50.5/49.4 (C11, C12, rotamers), 49.0 (C7), 35.3 (C10), 28.2 (3C, Boc), 27.6 (C8), 26.3 (C9); HRMS (ESI.sup.+): calculated for C.sub.28H.sub.32N.sub.3O.sub.4: 474.2387, found [M+H].sup.+: 474.2383, calculated for C.sub.28H.sub.31N.sub.3NaO.sub.4: 496.2207, found [M+Na].sup.+: 496.2198.

Example 10b—(+)4-(4-(2-Pyridone))cytisine hydrochloride salt (106)

(70) ##STR00026##

(71) To a solution of N-Boc 4-(4-(2-benzyloxy)pyridine)cytisine 105 (448 mg, 0.95 mmol) in MeOH (5.7 mL) was added HCl (2.9 mL, conc. aq. sol.). The mixture was heated at reflux for 24 h. After cooling to r.t., the solvent was removed in vacuo. The crude was solubilized in MeOH (55 mL) and acetone (550 mL) was added. The mixture was stirred for 2 h. The solids were filtered, washed with acetone and dried to give 106 (254 mg, 84%) as a pale yellow solid.

(72) mp: >200° C., colourless powder; [α].sub.D.sup.23=+26 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2946, 2732, 2582, 1638, 1567; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 7.56 (d, 1H, J=6.5 Hz, C18-H), 6.77-6.64 (m, 4H, C3-H, C5-H, C15-H, C19-H), 4.19 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.00 (dd, 1H, J=5.5, 15.5 Hz, C7-H.sub.b), 3.56-3.34 (m, 5H, C10-H, C11-H, C12-H), 2.89 (s, 1H, C8-H), 2.23-2.09 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.3 (C16), 164.0 (CO), 150.4 (C14), 148.4 (C4), 147.8 (C6), 135.4 (C18), 116.3, 114.3 (C15, C19), 107.2 (C3), 106.9 (C5), 49.3 (C11 or C12), 48.7 (C7), 48.2 (C11 or C12), 31.6 (C10), 24.7 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.17N.sub.3O.sub.2: 284.1394, found [M+H—HCl].sup.+: 284.1386.

Example 11—(−)N-Boc 4-Chlorocytisine (59)

(73) ##STR00027##

(74) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine outlined in Example 1 above in a 1.00 mmol scale.

(75) The borylation reaction crude mixture was solubilized in MeOH (2.5 mL). A solution of CuCl.sub.2 (470 mg, 3.5 mmol) in H.sub.2O (2.5 mL) was added and the mixture was stirred at r.t. for 4 days under air. The mixture was diluted with NH.sub.4OH (10 mL, 15% aq.sol.) and the aqueous phase was extracted with DCM (3×10 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 59 (247 mg, 76%) as an off-white solid.

(76) R.sub.f: 0.21 [EtOAc]; mp: 148-149° C. (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2976, 2925, 1678, 1639, 1539; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.43 (s, 1H, C3-H), 6.08 (s, 1H, C5-H), 4.34-4.07 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.74 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.12-2.94 (m, 3H, C10-H, C11-H, C12-H), 2.40 (s, 1H, C8-H), 1.90 (s, 2H, C9-H), 1.31-1.22 (m, 9H, Boc); .sup.13C NMR (100 Hz, CDCl.sub.3, δ.sub.C): 162.5 (CO), 154.5/154.2 (CO Boc, rotamers), 149.9/149.4 (C4, rotamers), 146.1/145.8 (C6, rotamers), 115.7 (C3), 107.1/106.4 (C5, rotamers), 80.5/80.0 (q Boc, rotamers), 51.5/50.5/50.1/49.2 (C11, C12, rotamers), 48.9 (C7), 34.8 (C10), 28.0 (3C, Boc), 27.4 (C8), 26.0 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22ClN.sub.2O.sub.3: 325.1313, found [M+H].sup.+: 325.1301, calculated for C.sub.16H.sub.21ClN.sub.2NaO.sub.3: 347.1133, found [M+Na].sup.+: 347.1121.

Example 12—(−)4-Chlorocytisine (60)

(77) ##STR00028##

(78) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as outlined above in Example 1 in a 1.00 mmol scale.

(79) In a sealed tube, the borylation reaction crude mixture was solubilized in MeOH (2.5 mL) and an aqueous solution of CuCl.sub.2 (470 mg, 3.5 mmol, 1.4 M) was added. The reaction was stirred at 90° C. for 18 h. The reaction was coded, diluted with NH.sub.4OH (5 mL, 15% aq. sol.) and the aqueous phase was extracted with DCM (5×5 mL). The combined organic layers were concentrated in vacuo. The residue was partitioned between 3M HCl (5 mL) and DCM (5 mL). The aqueous layer was washed with DCM (2×5 mL), basified with concentrated NH.sub.4OH to pH 10 and extracted with DCM (5×5 mL). The combined organic layers were dried on Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH/ammonia (89:10:1)] to give 60 (179 mg, 80%) as an off-white solid. A high purity sample was obtained by recrystallization in toluene.

(80) R.sub.f: 0.22 [DCM/MeOH (10% MeOH)]; mp: 167-168° C., colourless solid (toluene); [α].sub.D.sup.25=−32 [c 1.0, EtOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3330, 3064, 2930, 2793, 1634, 1538; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.45 (d, 1H, J=2.0 Hz, C3-H), 6.02 (d, 1H, J=2.0 Hz, C5-H), 4.03 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.82 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.07-2.85 (m, 4H, C11-H, C12-H), 2.85 (s, 1H, C10-H), 2.31 (s, 1H, C8-H), 1.92 (s, 2H, C9-H), 1.36 (s, 1H, NH); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.7 (CO), 151.8 (C4), 146.0 (C6), 115.2 (C3), 106.3 (C5), 53.7, 52.9 (C11, C12), 49.8 (C7), 35.6 (C10), 27.5 (C8), 26.2 (C9); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.14ClN.sub.2O: 225.0789, found [M+H].sup.+: 225.0791. Anal. Calc. for C.sub.11H.sub.13ClN.sub.2O: theor. C=58.80, H=5.83, N=12.47, found C=58.40, H=5.86, N=12.32.

Example 13a—(−)N-Boc 4-Iodocytisine (64)

(81) ##STR00029##

(82) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as detailed in Example 1 above in a 5.00 mmol scale.

(83) Cu(NO.sub.3).sub.2.Math.3H.sub.2O (2.42 g, 10.0 mmol), NH.sub.4I (1.45 g, 10.0 mmol) and sieves molecules 4 Å (500 mg) were added over the crude borylation reaction mixture, and the Schlenk flask was placed under nitrogen and backfilled with oxygen for three times. The reaction mixture was dissolved in DMF (25 mL) and heated at 80° C. for 24 h. The solvent was removed in vacuo and the residue was dissolved in DCM. The mixture was poured over ammonia (30 mL, 15% aq. sol.) and the aqueous phase was extracted with DCM (4×25 mL). The combined organic layers were dried on MgSO.sub.4, filtered and concentrated, and the crude was purified by flash column chromatography [DCM/MeOH (2% MeOH)]) yielding iodide 64 (1.99 g, 95%) as an off-yellow solid.

(84) R.sub.f: 0.21 [DCM:MeOH (3% MeOH)]; mp: 139-140° C., needles (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2920, 1679, 1632, 1523; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H, 52.0° C.): 6.90 (d, J=2.0 Hz, 1H, C3-H), 6.37 (d, J=2.0 Hz, 1H, C5-H), 4.39-4.04 (m, 3H, C11-H, C12-H, C7-H), 3.72 (dd, J=16.0, 7.0 Hz, 1H, C7-H), 3.09-2.93 (m, 2H, C11-H, C12-H), 2.89 (s, 1H, C10-H), 2.39 (s, 1H, C8-H), 1.99-1.87 (m, 2H, C9-H), 1.26 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C, 52.0° C.): 161.6 (CO), 154.3 (CO Boc), 148.8 (C6), 126.3 (C3), 114.3 (C5), 108.2 (C4), 80.1 (q Boc), 50.4, 49.3 (C11, C12), 48.8 (C7), 34.5 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.1 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22IN.sub.2O.sub.3: 417.0670, found [M+H].sup.+: 417.0672; calculated for C.sub.16H.sub.21IN.sub.2NaO.sub.3: 439.0489, found [M+Na].sup.+: 439.0491.

Example 13b—(+)4-Iodocytisine hydrochloride salt (65)

(85) ##STR00030##

(86) Following the general procedure A, N-Boc 4-Iodocytisine 64 (0.68 mmol) gave 65 (0.18 g, 86%) as a colourless solid.

(87) mp: >200° C., colourless powder; [α].sub.D.sup.21=+12 [c 1.0, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2714, 1615, 1551, 1455; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 7.07 (s, 1H, C3-H), 6.89 (s, 1H, C5-H), 4.03 (d, J=15.5 Hz, 1H, C7-H), 3.88 (dd, J=15.5, 6.0 Hz, 1H, C7-H), 3.44 (s, 1H, C10-H), 3.41-3.29 (m, 4H, C11-H C12-H), 2.76 (s, 1H, C8-H), 2.08-1.98 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 163.3 (CO), 146.8 (C6), 126.4 (C3), 118.9 (C5), 110.7 (C4), 49.3, 48.2 (C11, C12), 48.7 (C7), 31.0 (C10), 24.7 (C8), 22.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.14IN.sub.2O: 317.0145, found [M+H.sup.+—HCl].sup.+: 317.0141.

Example 14a—(−)N-Boc 4-Trifluoromethylcytisine (76)

(88) ##STR00031##

(89) A Schlenk flask was charged with N-Boc 4-iodocytisine 64 (2.08 g, 5 mmol), copper iodide (4.52 g, 23.7 mmol), potassium fluoride anhydrous (1.38 g, 23.7 mmol) and trimethyl (trifluoromethyl)silane (3.5 mL, 23.7 mmol) and the reaction mixture was placed under nitrogen. DMF (24 mL, 0.2 M) was added and the reaction mixture was stirred at 50° C. for 16 h. The solvent was removed in vacuo and the residue distributed between DCM (20 mL) and ammonia (20 mL, 15% aq. sol.). The aqueous phase was extracted with DCM (3×20 mL) and the combined organic phases were dried over MgSO.sub.4, the solids were filtered off and the solvent was evaporated in vacuo. Purification of the crude of the reaction by flash column chromatography [EtOAc/n-Hexane (4:1)] yielded 76 (1.52 g, 85%) as a colourless solid.

(90) mp: 150-151° C., colourless solid (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2981, 1680, 1664, 1547; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.73 (s, 1H, C3-H), 6.22 (s, 1H, C3-H), 4.48-4.15 (m, 3H, C11-H C12-H C7-H), 3.85 (dd, 1H, J=16.0, 6.5 Hz, C7-H), 3.22-2.95 (m, 3H, C11-H, C12-H, C8-H), 2.49 (s, 1H, C10-H), 2.02 (m, 2H, C7-H), 1.43-1.15 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 162.2 (CO), 153.6 (d, J=43.0 Hz, CO Boc), 151.0 (d, J=53.0 Hz, C6), 140.5 (C4), 122.3 (d, J=273 Hz, C13), 114.1 (C3), 100.1 (d, J=83.0 Hz, C5), 80.0 (d, J=62.0 Hz, q Boc), 51.1, 50.3 (C11, C12), 49.3 (C7), 35.3 (C10), 28.0 (3C, Boc), 27.4 (C8), 26.0 (C9); .sup.19F NMR (470 MHz, CDCl.sub.3, δ.sub.F): −66.5 (d, J=102 Hz); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.22F.sub.3N.sub.2O.sub.3: 359.1577, found [M+H].sup.+: 359.1584, calculated for C.sub.17H.sub.21F.sub.3N.sub.2NaO.sub.3: 381.1396, found [M+Na].sup.+: 381.1406; Anal. Calc: calculated: C, 56.9; H, 5.91; N, 7.82. found: C, 56.6; H, 5.5; N, 8.1.

Example 14b—(−)4-Trifluoromethylcytisine hydrochloride salt (77)

(91) ##STR00032##

(92) Following the general procedure A, N-Boc 4-trifluoromethylcytisine 76 (0.28 mmol) gave 77 (55 mg, 77%) as a colourless solid.

(93) mp: >200° C.; colourless powder; [α].sub.D.sup.26=−66 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 1658, 1551, 1278, 1166, 857; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.82 (s, 1H, C3-H), 6.70 (s, 1H, C5-H), 4.11 (d, 1H, J=15.5 Hz, C7-H), 3.97 (d, 1H, J=15.5, 6.5 Hz, C7-H), 3.53-3.30 (m, 5H, C11-H C12-H C10-H), 2.78 (s, 1H, C8-H), 2.05 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.3 (CO), 149.3 (C6), 141.5 (q, J=34.0 Hz, C4), 122.2 (q, J=273.0 Hz, CF.sub.3), 114.5 (C3), 104.4 (C5), 49.2, 48.9 (C11, C12), 48.2 (C7), 31.8 (C10), 24.7 (C8), 22.3 (C9); .sup.19F NMR (376 MHz, D.sub.2O, δC, ppm): −66.2 (s); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.14F.sub.3N.sub.2O; 259.1053, found [M+H—HCl].sup.+: 259.1060.

Example 15a—N-Boc4-Bromocytisine (61)

(94) ##STR00033##

(95) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine detailed in Example 1 above in a 5.00 mmol scale.

(96) The borylation reaction crude mixture was solubilized in MeOH (12.5 mL) and cooled to 0° C. A solution of CuBr.sub.2 (3.35 g, 15.0 mmol) in H.sub.2O (12.5 mL) was added over 5 min. The ice bath was removed after 30 min and the reaction mixture was stirred at r.t. for two days in an open-air flask. The mixture was diluted with NH.sub.4OH (25 mL, 15% aq.sol.) and the aqueous phase extracted with DCM (3×50 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 61 (1.54 g, 83%) as an off-white solid.

(97) R.sub.f: 0.25 [EtOAc]; mp: 163-164° C., off-white solid (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2976, 2924, 1679, 1635, 1531; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.66 (s, 1H, C3-H), 6.21 (s, 1H, C5-H), 4.35-4.06 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.73 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.10-2.93 (m, 3H, C10-H, C11-H, C12-H), 2.40 (s, 1H, C8-H), 1.94 (s, 2H, C9-H), 1.31-1.23 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.2 (CO), 154.4/154.2 (CO Boc, rotamers), 149.6/149.1 (C6, rotamers) 135.1/134.6 (C4, rotamers), 119.2 (C3), 109.6/109.0 (C5, rotamers), 80.5/80.0 (q Boc, rotamers), 51.5/50.5/50.1/49.2 (C11, C12, rotamers), 48.9 (C7), 34.7 (C10), 28.0 (3C, Boc), 27.3 (C8), 26.0 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22BrN.sub.2O.sub.3: 369.0808, found [M+H].sup.+: 369.0797, calculated for C.sub.16H.sub.21BrN.sub.2NaO.sub.3: 391.0628, found [M+Na].sup.+: 391.0620.

Example 15b—(−)4-Bromocytisine (62)

(98) ##STR00034##

(99) N-Boc-4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-cytisine 58 was made following the general procedure for the borylation of cytisine as detailed above in Example 1 in a 1.00 mmol scale.

(100) The borylation reaction crude mixture was solubilized in MeOH (2.5 mL) in a sealed tube, and a solution of CuBr.sub.2 (670 mg, 3.0 mmol) in H.sub.2O (2.5 mL) was added. The mixture was heated at 80° C. overnight. The mixture was cooled, diluted with NH.sub.4OH (5 mL, 15% aq.sol.) and extracted with DCM (5×5 mL). The combined organic layers were concentrated in vacuo. The crude was partitioned between 3M HCl (5 mL) and DCM (5 mL). The aqueous layer was washed with DCM (2×5 mL), basified with concentrated NH.sub.4OH to pH 10 and extracted with DCM (5×5 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH: (89:10:1)] to give bromide 62 (228 mg, 85%) as an off-white solid. A high purity sample was obtained by recrystallization in toluene.

(101) R.sub.f: 0.21 [DCM/MeOH (10% MeOH)]; mp: 169-170° C., off-white solid (toluene); [α].sub.D.sup.25=−32 [c 1.0, EtOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3335, 3061, 2934, 2791, 2741, 1622, 1531; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.67 (d, 1H, J=2.0 Hz, C3-H), 6.17 (d, 1H, J=2.0 Hz, C5-H), 4.04 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.83 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.10-2.97 (m, 4H, C11-H, C12-H), 2.87-2.86 (m, 1H, C10-H), 2.35-2.32 (m, 1H, C8-H), 1.94 (s, 2H, C9-H), 1.46 (s, 1H, NH); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.5 (CO), 151.6 (C4), 135.0 (C6), 118.7 (C3), 108.8 (C5), 53.7, 52.9 (C11, C12), 49.8 (C7), 35.5 (C10), 27.6 (C8), 26.2 (C19); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.14BrN.sub.2O: 269.0284, found [M+H].sup.+: 269.0289.

Example 16a—N-Boc 4-aminocytisine (80)

(102) ##STR00035##
Method A:

(103) In a Schlenk tube, a mixture of N-Boc-4-bromo-cytisine 61 (184 mg, 0.5 mmol), NaN.sub.3 (65 mg, 1.0 mmol), CuI (9 mg, 10 mol %), L-proline (17 mg, 30 mol %), NaOH (6 mg, 30 mol %) in EtOH/H.sub.2O (7:3) (5 mL) was heated at 95° C. overnight. The mixture was cooled and partitioned between H.sub.2O and DCM. The aqueous layer was extracted with DCM (2×10 mL). The combined organic layers were washed with brine, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (89:10:1)] to give amine 80 (116 mg, 76%) as an off-white solid.

(104) Method B:

(105) A mixture of N-Boc-4-bromo-cytisine 61 (92 mg, 0.25 mmol) and copper (2 mg, 10 mol %) in NH.sub.4OH (0.5 mL, conc. aq. sol.) was stirred at 100° C. for 24 h in a sealed tube. The mixture was cooled and extracted with DCM (5×5 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH: (89:10:1)] to give 80 (64 mg, 85%) as an off-white solid.

(106) R.sub.f: 0.28 [DCM/MeOH (10% MeOH)]; mp: >200° C.; FTIR v.sub.max/cm.sup.−1 (neat): 3414, 3302, 3211, 2905, 1679, 1642, 1551; .sup.1H NMR (400 MHz, MeOD, δ.sub.H): 5.83 (s, 1H, C3-H), 5.51 (s, 1H, C5-H), 4.29-4.02 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.68 (dd, 1H, J=6.5, 14.5 Hz, C7-H.sub.b), 3.34-2.93 (m, 3H, C10-H, C11-H, C12-H), 2.36 (s, 1H, C8-H), 1.98 (s, 2H, C9-H), 1.34-1.24 (m, 9H, Boc); .sup.13C NMR (100 MHz, MeOD, δ.sub.C): 165.2 (CO), 157.7 (CO Boc), 154.7 (C6), 149.0/148.8 (C4, rotamers), 99.6/99.3 (C3, rotamers), 91.9 (C5), 80.1/79.6 (q Boc, rotamers), 51.4/50.2/50.1 (C11, C12, rotamers), 49.0 (C7), 34.9 (C10), 27.9/27.7 (C8, rotamers), 27.0 (3C, Boc), 25.7 (C9); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.24N.sub.3O.sub.3: 306.1812, found [M+H].sup.+: 306.1809.

Example 16b—(+)4-aminocytisine dihydrochloride salt (81)

(107) ##STR00036##

(108) Following the general procedure A, N-Boc 4-amino-cytisine 80 (1.0 mmol) gave amine 81 (273 mg, 98%) as an off-white solid.

(109) mp: >200° C.; [α].sub.D.sup.25=+77 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2929, 2790, 1649, 1533; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.26 (s, 1H, C3-H), 4.09 (d, 1H, J=15.0 Hz, C7-H.sub.a), 3.95 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.41-3.26 (m, 5H, C10-H, C11-H, C12-H), 2.68 (s, 1H, C8-H), 2.07-1.94 (m, 2H, C9-H), C5-H not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 160.9 (CO), 159.1 (C4), 148.1 (C6), 104.5 (d, J=7.2 Hz, C3), 91.5-91.0 (m, C5), 49.2 (C11 or C12), 48.8 (C7), 48.1 (C11 or C12), 31.2 (C10), 24.5 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.16N.sub.3O: 206.1288, found [M+H-2HCl].sup.+: 206.1292.

Example 17—(−)4-Fluorocytisine (82)

(110) ##STR00037##

(111) To a solution of N-Boc-4-amino-cytisine 80 (305 mg, 1.0 mmol) in HF-pyridine complex (70%, 2.0 mL) at −20° C. was slowly added tBuONO (0.18 mL, 1.5 mmol) over 1 min. The reaction was stirred at −20° C. for 30 min, then allowed to warm to r.t. for 2 h and finally heated at 60° C. overnight. The mixture was cooled to 0° C. and quenched to pH 10 with conc. aq. NH.sub.4OH. The mixture is diluted with EtOAC (10 mL) and filtered to remove the insoluble salts. The aqueous layer was extracted with EtOAc (4×10 mL). The combined organic layers were concentrated in vacuo. The crude was partitioned between 3M HCl (5 mL) and DCM (5 mL). The aqueous layer was washed with DCM (2×5 mL), basified with concentrated NH.sub.4OH to pH 10 and extracted with DCM (5×5 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (89:10:1)] to give 82 (140 mg, 67%) as a pale yellow solid. An analytic pure sample was obtained by recrystallization in toluene.

(112) R.sub.f: 0.25 [DCM/MeOH (20% MeOH)]; mp: 143-145° C. (toluene); [α].sub.D.sup.25=−92 [c 1.0, EtOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3391, 3289, 3069, 2948, 2898, 2852, 1644, 1552; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.06 (dd, 1H, J=2.5, 11.0 Hz, C3-H), 5.87 (dd, 1H, J=2.5, 7.0 Hz, C5-H), 4.04 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.83 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.08-2.95 (m, 4H, C11-H, C12-H), 2.89-2.86 (m, 1H, C10-H), 2.34-2.29 (m, 1H, C8-H), 1.93 (t, 2H, J=3.0 Hz, C9-H), 1.56 (br s, 1H, NH); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 169.9 (d, J=264.0 Hz, C4), 164.8 (d, J=19.0 Hz, CO), 153.5 (d, J=13.5 Hz, C6), 99.6 (d, J=16.5 Hz, C3), 96.5 (d, J=26.0 Hz, C5), 53.7, 52.9 (C11, C12), 49.8 (C7), 36.0 (d, J=2.0 Hz, C10), 27.5 (C8), 26.2 (C9); .sup.19F NMR (376 MHz, CDCl.sub.3, δ.sub.F): −99.6 (m); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.14FN.sub.2O: 209.1090, found [M+H].sup.+: 209.1095. Anal. Calc. for C.sub.11H.sub.13FN.sub.2O: theor. C=63.45, H=6.29, N=13.45, found C=63.05, H=6.33, N=13.20.

Example 18a—N-Boc 4-N-Methylamino)cytisine (83)

(113) ##STR00038##

(114) A mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and copper (7 mg, 10 mol %) in 40% aq. MeNH.sub.2 (2.0 mL) was stirred at 100° C. for 24 h in a sealed tube. The mixture was cooled to r.t. and extracted with DCM (5×10 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash chromatography on silica gel (DCM/MeOH (94:6)] to give 83 (274 mg, 86%) as an off-white solid.

(115) R.sub.f: 0.58 [DCM/MeOH (10% MeOH)]; mp: 198-200° C. (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 3266, 2928, 1684, 1641, 1571; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 5.49 (s, 1H, C3-H), 5.37 (s, 1H, C5-H), 4.53 (s, 1H, NH), 4.28-4.03 (m, 3H, C7-H.sub.a, C10-H, C12-H), 3.72 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.02-2.70 (m, 6H, C10-H, C11-H, C12-H, C14-H), 2.31 (s, 1H, C8-H), 1.93-1.81 (m, 2H, C9-H), 1.32-1.22 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 164.7 (CO), 156.0 (CO Boc), 154.8/154.5 (C6, rotamers), 147.9/147.3 (C4, rotamers), 98.0/97.2 (C3, rotamers), 90.4/90.1 (C5, rotamers), 80.2/79.6 (q Boc, rotamers), 51.7/50.7/50.4/49.4 (C11, C12, rotamers), 47.9 (C7), 34.8 (C10), 29.4 (C14), 28.1 (3C, Boc), 27.6 (C8), 26.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.26N.sub.3O.sub.3: 320.1969, found [M+H].sup.+: 320.1974.

Example 18b—(+)4-(N-Methylamino)cytisine dihydrochloride salt (84)

(116) ##STR00039##

(117) Following the general procedure A, 4-N-methylamino-N-Boc-cytisine 83 (0.77 mmol) gave amine 84 (190 mg, 85%) as a colourless solid.

(118) mp: >200° C., colourless powder; [α].sub.D.sup.25=+66 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3240, 2939, 2714, 2583, 1644, 1557; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.25 (s, 1H, C3-H), 4.09 (d, 1H, J=15.0 Hz, C7-H.sub.a), 3.95 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.42-3.26 (m, 5H, C10-H, C11-H, C12-H), 2.71 (s, 4H, C8-H, C14-H), 2.05-1.94 (m, 2H, H.sub.9), C5-H not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 160.7 (CO), 158.7 (C4), 147.1 (C6), 103.6 (C3), 88.4-87.9 (C5), 49.3 (C11 or C12), 48.7 (C7), 48.1 (C11 or C12), 31.3 (C10), 28.5 (C14), 24.5 (C8), 22.6 (C9); HRMS(ESI.sup.+): calculated for C.sub.12H.sub.18N.sub.3O: 220.1444, found [M+H-2HCl].sup.+: 220.1441.

Example 19a—N-Boc 4-(N,N′-Dimethylamino)cytisine (85)

(119) ##STR00040##

(120) A mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and copper (6 mg, 10 mol %) in 40% aq. Me.sub.2NH (2.0 mL) was stirred at 100° C. for 24 h in a sealed tube. The mixture was cooled, diluted with 35% ammonia (2 mL) and the aqueous phase was extracted with DCM (5×10 mL). The combined organic layers were dried on Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (94.5:5:0.5)] to give 85 (212 mg, 64%) as a white foam.

(121) R.sub.f: 0.19 [DCM/MeOH (10% MeOH)]; FTIR v.sub.max/cm.sup.−1 (neat): 2972, 2928, 2863, 1687, 1645, 1578; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 5.64 (d, 1H, J=2.5 Hz, C3-H), 5.42 (s, 1H, C5-H), 4.31-4.04 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.73 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.04-2.81 (m, 9H, C10-H, C11-H, C12-H, 2×C14-H), 2.31 (s, 1H, C8-H), 1.94-1.83 (m, 2H, C9-H), 1.32-1.19 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 164.2 (CO), 156.0 (CO Boc), 154.8/154.4 (C4, rotamers), 147.9/147.5 (C6, rotamers), 95.6/95.1 (C3, rotamers), 91.9/91.5 (C5, rotamers), 80.2/79.5 (q Boc, rotamers), 51.8/50.7/50.4/49.3 (C11, C12, rotamers), 47.8 (C7), 39.3 (2C, C14), 35.2 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.28N.sub.3O.sub.3: 334.2125, found [M+H].sup.+: 334.2113.

Example 19b—(+)4-(N,N′-dimethylamino)cytisine dihydrochloride salt (86)

(122) ##STR00041##

(123) Following the general procedure A, N-Boc-4-N,N′-dimethylamino-cytisine 85 (202 mg, 0.61 mmol) gave amino 86 (174 mg, 93%) as a colourless solid.

(124) mp: >200° C., colourless powder; [α].sub.D.sup.25=+84 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3202, 2960, 2753, 1644, 1551; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.41 (s, 1H, C3-H), 4.12 (d, 1H, J=15.0 Hz, C7-H.sub.a), 3.98 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.42-3.27 (m, 5H, C10-H, C11-H, C12-H), 2.96 (s, 6H, C14-H), 2.68 (s, 1H, C8-H), 2.07-1.96 (m, 2H, C9 H), H.sub.5 not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 159.8 (CO), 157.4 (C4), 147.1 (C6), 102.5 (d, J=5.0 Hz, C3), 89.0-88.5 (m, C5), 49.3 (C11 or C12), 48.7 (C7), 48.1 (C11 or C12), 39.1 (2C, C14), 31.5 (C10), 24.5 (C8), 22.6 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.20N.sub.3O [M+H-2HCl].sup.+: 234.1601, found: 234.1606.

Example 20a—N-Boc 4-(N-benzoylamino)cytisine (95)

(125) ##STR00042##

(126) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), CuI (19 mg, 10 mol %), benzamide (145 mg, 1.2 mmol) and K.sub.2CO.sub.3 (276 mg, 2.0 mmol) in dry toluene (5.0 mL) was added N,N′-dimethylethylenediamine (11 μL, 10 mol %). The mixture was heated at 110° C. for three days. After cooling, the mixture was diluted with H.sub.2O (10 mL) and the aqueous phase was extracted with DCM (5×10 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (95:5:0.1)] to give the 95 (425 mg) as a yellow solid. The resultant solid was washed in boiling toluene (10 mL) overnight to give 95 (372 mg, 91%) as a colourless solid.

(127) R.sub.f: 0.49 [DCM/MeOH (10% MeOH)]; mp: >200° C., colourless powder; FTIR v.sub.max/cm.sup.−1 (neat): 3067, 2972, 2864, 1648, 1626, 1548, 1483; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.74-7.72 (m, 2H, C17-H), 7.40-7.28 (m, 3H, C18-H, C19-H), 7.06/6.75 (2 br s, 2×0.5H, C3-H, rotamers), 6.62/6.33 (2 br s, 2×0.5H, C5-H, rotamers), 4.08-3.94 (m, 4H, NH, C7-H.sub.a, C11-H, C12-H), 3.61 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.16-2.91 (m, 3H, C10-H, C11-H, C12-H), 2.27 (s, 11H, C8-H), 1.83 (s, 2H, C9-H), 1.16-1.05 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 167.5 (C14), 164.5 (CO), 154.5 (CO Boc), 149.5, 148.8 (C6, C4), 133.9 (C16), 131.9 (C19), 128.2 (C17, C21), 127.4 (C18, C20), 102.2/101.9 (C3, rotamers), 101.2 (C5), 80.5/79.9 (q Boc, rotamers), 51.3/50.3/50.1/49.1/48.9/48.7/48.5/48.4/48.2/48.0/47.8 (C7, C11, C12, rotamers), 34.8 (C10), 27.5 (3C, Boc), 27.2 (C8), 25.7 (C9); HRMS (ESI.sup.+): calculated for C.sub.23H.sub.28N.sub.3O.sub.4: 410.2074, found [M+H].sup.+: 410.2064, calculated for C.sub.23H.sub.27N.sub.3NaO.sub.4: 432.1894, found [M+Na].sup.+: 432.1884.

Example 20b—(+)4-(N-Benzoylamino)cytisine hydrochloride salt (96)

(128) ##STR00043##

(129) Following the general procedure B, N-Boc-4-(N-benzamide)-cytisine 95 (363 mg, 0.89 mmol) gave benzamide 96 (290 mg, 80%) as a colourless solid.

(130) mp: >200° C., colourless powder; [α].sub.D.sup.26=+30 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2937, 2798, 1677, 1633, 1599; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 7.55 (d, 2H, J=7.5 Hz, C17-H, C21-H), 7.45-7.42 (m, 1H, C19-H), 7.32-7.28 (m, 2H, C18-H, C20-H), 6.76 (d, 1H, J=2.0 Hz, C3-H), 6.62 (d, 1H, J=2.0 Hz, C5-H), 3.96 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.70 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.39-3.23 (m, 5H, C10-H, C11-H, C12-H), 2.64 (s, 1H, C8-H), 1.96 (d, 1H, J=13.5 Hz, C9-H), 1.76 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 169.1 (C14), 164.6 (CO), 149.2 (C4), 147.6 (C6), 133.0 (C19), 132.6 (C16), 128.7 (C18, C20), 127.5 (C17, C21), 104.1 (C5), 102.8 (C3), 49.2 (C11 or C12), 48.6 (C7), 48.2 (C11 or C12), 31.5 (C10), 24.6 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.20N.sub.3O.sub.2: 310.1550, found [M+H—HCl].sup.+: 310.1549.

Example 21a—N-Boc 4-(N-acetylamino)cytisine (93)

(131) ##STR00044##

(132) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), CuI (19 mg, 10 mol %), acetamide (70 mg, 1.2 mmol) and K.sub.2CO.sub.3 (276 mg, 2.0 mmol) in dry toluene (5.0 mL) was added N,N′-dimethylethylenediamine (11 μL, 10 mol %). The mixture was heated at 110° C. for 24 h. After cooling to r.t., the mixture was diluted with H.sub.2O (10 mL), then extracted with DCM (5×10 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (95:5:0.1)] to give 93 (340 mg, 98%) as a pale yellow foam with few impurities. The product was used in the next step without further purification.

(133) R.sub.f: 0.49 [DCM/MeOH (10% MeOH)]; FTIR v.sub.max/cm.sup.−1 (neat): 2971, 2929, 1688, 1644, 1556, 1422; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.11/6.74 (2×s, 1H, C3-H, rotamers), 6.58/6.23 (2×s, 1H, H5, rotamers), 4.34-4.12 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.77 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.04-2.97 (m, 3H, C10-H, C11-H, C12-H), 2.51 (s, 1H, C8-H), 2.09 (s, 3H, C16-H), 2.01-1.89 (m, 2H, C9-H), 1.33-1.21 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 170.2 (C15), 164.4 (CO), 154.8/154.5 (CO Boc, rotamers), 148.5, 148.3 (C6, C4), 101.9 (C3), 100.4 (C5), 80.7/79.6 (q Boc, rotamers), 51.6/50.7/50.5/49.3 (C11, C12, rotamers), 48.6 (C7), 35.0 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.2 (C9), 24.6 (C16); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.26N.sub.3O.sub.4: 348.1918, found [M+H].sup.+: 348.1916, C.sub.18H.sub.25N.sub.3NaO.sub.4: 370.1737, found [M+Na].sup.+: 370.1737.

Example 21b—(+)4-(N-acetylamino)cytisine (94)

(134) ##STR00045##

(135) Following the general procedure B, N-Boc-4-(N-acetamide)-cytisine 93 (306 mg, 0.88 mmol) gave 94 (250 mg, quantitative) as a pale yellow solid.

(136) mp: >200° C., colourless powder; [α].sub.D.sup.25=+30 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2457, 2374, 1612, 1530, 1506; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.79 (d, 1H, J=2.0 Hz, C3-H), 6.64 (d, 1H, J=2.0 Hz, C5-H), 4.04 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.88 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.40-3.25 (m, 5H, C10-H, C11-H, C12-H), 2.70 (s, 1H, C8-H), 2.05-1.91 (m, 5H, C9-H, C16-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 173.6 (C15), 164.5 (CO), 149.4 (C4), 148.1 (C6), 104.4 (C5), 101.7 (C3), 49.2 (C11 or C12), 48.8 (C7), 48.1 (C11 or C12), 31.5 (C10), 24.6 (C8), 23.6 (C16), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.18N.sub.3O.sub.2: 248.1394, found [M+H—HCl].sup.+: 248.1394.

Example 22—(+)4-N-morpholinecytisine dihydrochloride salt (92)

(137) ##STR00046##

(138) A sealed tube was charged with N-Boc-4-bromo-cytisine 61 (370 mg, 1.0 mmol), copper (II) oxide (15 mg, 0.1 eq.) and morpholine (0.4 mL, 5 eq.), and the reaction mixture was dissolved in water (2.0 mL, 0.5 M) and heated at 100° C. under air for 18 h. The reaction mixture was cooled to r.t. and the aqueous phase was extracted with DCM (4×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The resulting N-Boc protected cytisine derivative was deprotected and converted into the HCl salt using the general procedure A, yielding 92 (180 mg, 85%) as a colourless solid.

(139) mp: >200° C., colourless powder; [α].sub.D.sup.25=+61 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2560, 1641, 1541; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.48 (s, 1H, C3-H), 4.09 (d, 1H, J=16.0 Hz, C7-H), 3.96 (dd, 1H, J=16.0, 5.5 Hz, C7-H), 3.74 (s, 4H, C11-H, C12-H), 3.39 (m, 9H, CH.sub.2 morpholine, C10-H), 2.71 (s, 1H, C8-H), 2.04 (m, 2H, C9-H); C5-H is not visible due to H-solvent exchange; .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 162.5 (CO), 157.9 (C6), 147.4 (C4), 101.6 (C3), 91.7 (C5), 65.8 (2C, C15), 49.4, 48.2 (C11, C12), 48.4 (C7), 45.7 (2C, C16), 31.7 (C10), 24.6 (C8), 22.7 (C9); HRMS (ESI.sup.+): calculated for C.sub.15H.sub.22N.sub.3O.sub.2: 276.1707, found [M+H—HCl].sup.+: 276.1718.

Example 23a—N-Boc 4-(N-(L-proline methyl ester)cytisine (136)

(140) ##STR00047##

(141) A mixture of N-Boc 4-bromocytisine 61 (369 mg, 1.0 mmol), L-proline methyl ester hydrochloride (198 mg, 1.2 mmol), Cs.sub.2CO.sub.3 (814 mg, 2.5 mmol), Pd(OAc).sub.2 (11 mg, 5 mol %) and (±)-BINAP (44 mg, 7 mol %) in dry toluene (5.0 mL) was stirred for 48 h at 100° C. The mixture was cooled to r.t., filtered through a short pad of Celite,® washed with EtOAc and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (95:5:0.1)] to give 136 (371 mg, 89%) as an off-white foam with few impurities.

(142) R.sub.f: 0.11 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 5.55 (s, 1H, C3-H), 5.28 (s, 1H, C5-H), 4.27-4.02 (m, 4H, C7-H.sub.a, C11-H, C12-H, C15-H), 3.73-3.67 (m, 4H, C7-H.sub.b, C20-H), 3.48 (s, 1H, C18-H), 3.36 (s, 1H, C18-H), 3.00-2.85 (m, 3H, C10-H, C11-H, C12-H), 2.31-2.16 (m, 2H, C18-H, C16H), 2.08-1.99 (m, 3H, C16-H, C17-H), 1.91-1.81 (m, 2H, C9-H), 1.31-1.18 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 173.3 (C19), 164.0 (CO), 154.7/154.4 (CO Boc, rotamers), 153.0 (C4), 148.6/148.2 (C6, rotamers), 96.2/95.5 (C3, rotamers), 92.3 (C5), 80.2/79.6 (q Boc, rotamers), 60.0 (C15), 52.3 (C20), 50.7/50.6/50.4/49.4 (C11, C12, rotamers), 47.9 (C18), 47.8 (C7), 35.1 (C10), 30.6 (C16), 28.1 (3C, Boc), 27.5 (C8), 26.3 (C9), 23.5 (C17); HRMS (ESI.sup.+): calculated for C.sub.22H.sub.32N.sub.3O.sub.5: 418.2336, found [M+H].sup.+: 418.2340, calculated for C.sub.22H.sub.31N.sub.3NaO.sub.5: 440.2156, found [M+Na].sup.+: 440.2161.

Example 23b—(+)4-(N-(L-proline methyl ester)cytisine dihydrochloride salt (137)

(143) ##STR00048##

(144) Following the general procedure B, N-Boc-4-(N-(L-proline methyl ester)-cytisine 136 (0.88 mmol) gave 137 (304 mg, 89%) as a colourless solid.

(145) mp: >200° C., colourless powder; [α].sub.D.sup.26=+2 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2951, 2714, 2385, 1740, 1637, 1538, 1484; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.38 (s, 1H, C3-H), 4.62 (s, 1H, C15-H), 4.25 (d, 1H, J=15.0 Hz, C7-H.sub.a), 4.12 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.79 (s, 3H, C20-H), 3.60-3.40 (m, 7H, C10-H, C11-H, C12-H, C18-H), 2.82 (s, 1H, C8-H), 2.43-2.26 (m, 2H, C16-H), 2.18-1.99 (m, 4H, C14-H, C17-H), H3 not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 174.6 (C19), 160.9 (CO), 155.2 (C4), 147.8 (C6), 102.9 (C3), 60.5 (C15), 53.2 (C20), 49.3, 48.7, 48.6, 48.0 (C7, C11, C12, C18), 31.4 (C10), 30.1 (C16), 24.5 (C8), 23.0 (C17), 22.5 (C20), C3 not detected due to deuterium exchange; HRMS (ESI.sup.+): calculated for C.sub.17H.sub.24N.sub.3O.sub.3: 318.1812, found [M+H-2HCl].sup.+: 318.1802.

Example 24—(−)4-(N-(L-proline)cytisine dihydrochloride salt (138)

(146) ##STR00049##

(147) A mixture of N-Boc-4-(N-(L-proline methyl ester)-cytisine 138 (341 mg, 0.82 mmol) in HCl (37% in water, 8.2 mL) was heated at reflux for 48 h. The mixture was cooled to r.t. and concentrated in vacuo. The crude was solubilized in MeOH (4 mL) and then acetone was slowly added (40 mL). The resulting suspension was stirred for 1 h. The solid was filtered off, washed with acetone and dried under vacuum to give 138 (261 mg, 85%) as a pale brown solid.

(148) mp: >200° C., colourless powder; [α].sub.D.sup.26=−32 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2908, 2754, 2583, 1719, 1640, 1546; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.28 (s, 1H, C3-H), 4.51 (s, 1H, C15-H), 4.21 (d, 1H, J=15.0 Hz, C7-H.sub.a), 4.07 (dd, 1H, J=6.5, 15.0 Hz, C7-H.sub.b), 3.59-3.39 (m, 7H, C10-H, C11-H, C12-H, C18-H), 2.81 (s, 1H, C8-H), 2.46-2.36 (m, 1H, C16-H), 2.28-2.22 (m, 1H, C16-H), 2.17-2.01 (m, 4H, C14-H, C17-H), H.sub.5 not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 176.1 (C19), 160.8 (CO), 155.2 (C4), 147.8 (C6), 102.8 (C3), 60.6 (C15), 49.3, 48.8, 48.6, 48.0 (C7, C11, C12, C18), 31.4 (C10), 30.3 (C16), 24.5 (C8), 23.0 (C17), 22.5 (C9), C3 not detected; HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22N.sub.3O.sub.3 [M+H-2HCl].sup.+: 304.1656, found: 304.1651.

Example 25a—N-Boc 4-(carboxymethyl)cytisine (119)

(149) ##STR00050##

(150) A solution of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), Et.sub.3N (0.4 mL, 2.5 mmol), dppp (82 mg, 0.2 mmol) and Pd(OAc).sub.2 (45 mg, 0.2 mmol) in DMF/MeOH (1:1) (5 mL) was stirred at 80° C. under 1 atm of CO for 24 h. The mixture was cooled to r.t., filtered through Celite® and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 119 (300 mg, 86%) as a yellow foam.

(151) R.sub.f: 0.25 [EtOAc]; FTIR v.sub.max/cm.sup.−1 (neat): 2931, 1683, 1657, 1575, 1547; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.00 (s, 1H, C3-H), 6.54 (s, 1H, C5-H), 4.31-4.06 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.85 (s, 3H, Me), 3.79 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.14-2.88 (m, 3H, C10-H, C11-H, C12-H), 2.41 (s, 1H, C8-H), 1.98-1.91 (m, 2H, C9-H), 1.28-1.15 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 165.4 (C14), 163.2 (CO), 154.32 (CO Boc), 150.0/149.5 (C4, rotamers) 139.5 (C6), 118.4 (C3), 104.1/103.5 (C5, rotamers), 80.4/79.9 (q Boc, rotamers), 52.7 (C7), 51.5/50.5/50.3 (C11, C12, rotamers), 49.2 (Me), 35.0 (C10), 28.0 (3C, Boc), 27.4 (C8), 26.0 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.25N.sub.2O.sub.5: 349.1758, found [M+H].sup.+: 349.1750.

Example 25b—(−)4-carboxymethycytisine (120)

(152) ##STR00051##

(153) To a solution of N-Boc-4-methyl-ester-cytisine 119 (95 mg, 0.27 mmol) in DCM (1.3 mL) was added TFA (0.21 mL, 2.7 mmol). The mixture was stirred for 24 h then concentrated in vacuo. The crude was partitioned between HCl 3M (5 mL) and DCM (5 mL). The aqueous layer was washed with DCM (2×5 mL), basified with Na.sub.2CO.sub.3 to pH 9 and then extracted with DCM (5×5 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo to give 120 (55 mg, 81%) as an off-white solid. An analytic pure sample was obtained by recrystallization in toluene.

(154) R.sub.f: 0.23 [DCM/MeOH (10% MeOH)]; mp: 141-142° C., (toluene); [α].sub.D.sup.25=−96 [c 0.3, water]; FTIR v.sub.max/cm.sup.−1 (neat): 3300, 2926, 2893, 2847, 1719 (w), 1648, 1571; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.02 (d, 1H, J=1.5 Hz, C3-H), 6.49 (d, 1H, J=1.5 Hz, C5-H), 4.08 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.88 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.87 (s, 3H, Me), 3.08-2.95 (m, 5H, C10-H, C11-H, C12-H), 2.33 (s, 1H, C8-H), 1.97-1.90 (m, 2H, C9-H), 1.50 (s, 1H, NH); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 165.6 (COOMe), 163.4 (CO), 151.9 (C6), 139.4 (C4), 118.0 (C3), 103.3 (C5), 53.8, 52.9 (C12, C11), 52.7 (Me), 50.2 (C7), 35.8 (C10), 27.7 (C8), 26.2 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.17N.sub.2O.sub.3: 249.1234, found [M+H].sup.+: 249.1245.

Example 26—(−)4-Carboxylic acidcytisine, hydrochloride salt (229)

(155) ##STR00052##

(156) A solution of N-Boc-4-methyl-ester-cytisine 119 (263 mg, 0.75 mmol) in HCl (37% aq.sol. 7.5 mL) was heated at reflux for 24 h. The mixture was cooled to r.t. then concentrated in vacuo. The crude reaction mixture was solubilized in MeOH (30 mL) and then acetone was slowly added (300 mL). The resulting suspension was stirred for 1 h. The solids were filtered off, washed with acetone and dried under vacuum to give 229 (164 mg, 81%) as a colourless solid.

(157) mp: >200° C., colourless powder; [α].sub.D.sup.22=−33 [c 0.3, water]; FTIR v.sub.max/cm.sup.−1 (neat): 1698, 1648, 1543, 1471; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.88 (s, 1H, C3-H), 6.79 (s, 1H, C5-H), 4.06 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.91 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.44-3.27 (m, 5H, C10-H, C11-H, C12-H), 2.75 (s, 1H, C8-H), 2.08-1.96 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 167.7 (COOH), 164.8 (CO), 148.0 (C6), 142.1 (C4), 118.1 (C3), 107.8 (C5), 49.4 (C11 or C12), 49.0 (C7), 48.2 (C11 or C12), 31.7 (C10), 24.7 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.15N.sub.2O.sub.3: 235.1077, found [M+H—HCl].sup.+: 235.1078.

Example 27a—N-Boc 4-(hydroxymethyl)cytisine (121)

(158) ##STR00053##

(159) To a solution of N-Boc-4-methyl ester-cytisine 119 (350 mg, 1.00 mmol) in THF (4 mL) was added LiAlH.sub.4 (1.0 M in Et.sub.2O) dropwise at −78° C. during 5 min. and the reaction mixture was stirred for 3.5 h. EtOAc (2 mL) was added dropwise followed by the addition of a saturated Rochelle's salt solution (10 mL). The reaction mixture was stirred for 30 min, and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification by flash column chromatography [DCM/MeOH (2% MeOH to 5% MeOH)] yielded 121 (194 mg, 62%) as a colourless foam.

(160) mp: 201-203° C., colourless solid (toluene); .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.49 (s, 1H, C3-H), 6.16 (s, 1H, C5-H), 4.55 (s, 2H, C14-H), 4.28-4.16 (m, 3H, C7-H, C11-H, C12-H), 3.86 (dd, 1H, J=6.5, 16.0 Hz, C7-H), 3.19-2.92 (m, 3H, C11-H, C12-H, C10-H), 2.45 (s, 1H, C8-H), 1.99 (m, 2H, C9-H), 1.41-1.18 (m, 9H, Boc). .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.5 (CO), 154.6 (C6), 153.5 (C4), 112.7 (C3), 104.5 (C5), 80.6, 80.5 (C11, C12), 63.2 (C13), 48.8 (C7), 34.9 (C8), 28.0 (3C, Boc), 27.6 (C10), 26.2 (C9). The quaternary carbon of the boc group has not been found.

Example 27b—(−)4-(Hydroxymethyl)cytisine hydrochloride salt (122)

(161) ##STR00054##

(162) Following the general procedure A, N-Boc 4-hydroxymethylcytisine 121 (0.60 mmol) gave alcohol 122 (120 mg, 90%) as a colourless solid.

(163) mp: >200° C., colourless solid; [α].sub.D.sup.23=−24 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3292, 2726, 2323, 1643, 1571; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.50 (s, 1H, C3-H), 6.47 (s, 1H, C5-H), 4.50 (s, 2H, C14-H), 4.10 (d, 1H, J=15.0 Hz, C7-H), 3.96 (dd, 1H, J=15.0, 6.0 Hz, C7-H), 3.48-3.31 (m, 5H, C11-H C12-H C10-H), 2.77 (s, 1H, C8-H), 2.11-1.99 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.8 (CO), 156.1 (C4), 147.0 (C6), 112.5 (C3), 108.4 (C5), 61.5 (C13), 49.6 (C7), 48.5, 48.3 (C11, C12), 31.5 (C10), 24.7 (C8), 22.6 (C9); m/z (ESI.sup.+): 224 [M+H—HCl].sup.+; HRMS (ESI.sup.+): calculated for C.sub.12H.sub.16N.sub.2O.sub.2: 224.1757, found [M+H—HCl].sup.+: 224.1758.

Example 28a—N-Boc 4-(4-(Trifluoromethyl)benzyl)oxycytisine (123)

(164) ##STR00055##

(165) To a solution of the alcohol 121 (240 mg, 0.75 mmol) in dry THF (7.5 mL) was added NaH (33 mg, 1.1 eq., 60% dispersion in mineral oil) and the mixture was stirred at 0° C. After 30 min, TBAI (14 mg, 0.05 eq.) and 4-(trifluoromethyl) benzyl bromide (358 mg, 2 eq.) were added. The reaction was allowed to warm up to r.t. and stirred for 18 h. The reaction was quenched with water (10 mL) and the aqueous phase was extracted with EtOAc (3×15 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (1% MeOH)] to give 123 (250 mg, 71%) as colourless solid, which was used in the next step without further purification.

(166) FTIR v.sub.max/cm.sup.−1 (neat): 2975, 2931, 2864, 1686, 1660, 1545; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 7.60 (d, 2H, J=8.5 Hz, C18-H), 7.46 (d, 2H, J=8.5 Hz, C17-H), 6.42 (s, 1H, C3-H), 6.06 (d, 1H, J=1.5 Hz, C5-H), 4.58 (s, 2H, CH.sub.2), 4.37 (s, 2H, CH.sub.2), 4.26-4.08 (m, 3H, C7-H, C11-H, C12-H), 3.80 (dd, 1H, J=15.0, 6.5 Hz, C7-H), 3.13-2.89 (m, 3H, C10-H, C11-H, C12-H), 2.40 (s, 1H, C8-H), 1.95 (m, 2H, C9-H), 1.39-1.12 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.4 (CO), 154.6 (CO), 149.9 (C4), 148.5 (C6), 141.7 (CF.sub.3), 129.3 (q, J=33.8 Hz, Ar), 127.7 (2C, Ar), 125.4 (2C, Ar), 123.3 (Ar), 114.2 (C3), 104.5/103.7 (C5 rotamers), 80.4/79.4 (q Boc rotamers), 71.5 (CH.sub.2), 70.5 (CH.sub.2), 51.6/50.6/50.5/49.3 (C11, C12 rotamers), 48.8 (C7), 34.9 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.2 (C9); HRMS (ESI.sup.+): found [M+H].sup.+: 479.2142, calculated C.sub.25H.sub.30F.sub.3N.sub.2O.sub.4: 479.2152.

Example 28b—(−)4-(4-(Trifluoromethyl)benzyl)oxycytisine (124)

(167) ##STR00056##

(168) Ester 123 (0.25 g, 0.52 mmol) was converted into the HCl salt using the general procedure A yielding 124 (110 mg, 60%) as a colourless solid.

(169) mp: >200° C., colourless solid; [α].sub.D.sup.25=−18 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2974, 2930, 1687, 1658, 1545, 1421; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 7.65 (d, 2H, J=9.0 Hz, Ar), 7.50 (d, 2H, J=9.0, Ar), 6.47 (s, 1H, C3-H), 6.45 (s, 1H, C5-H), 4.64 (s, 2H, CH.sub.2), 4.48 (s, 2H, CH.sub.2), 4.07 (d, 1H, J=15.0 Hz, C7-H), 3.92 (dd, 1H, J=15.0, 6.0 Hz, C7-H), 3.47-3.28 (m, 5H, C10-H, C11-H, C12-H), 2.76 (s, 1H, C8-H), 2.07 (d, 1H, J=13.5 Hz, C9-H), 1.99 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.8 (CO), 152.4 (C4), 146.9 (C6), 141.2 (CF.sub.3), 129.6 (q, J=30 Hz, C—CF.sub.3), 128.7 (2C, Ar), 125.4 (2C, Ar), 123.4 (Ar), 114.4 (C3), 108.7 (C5), 72.1 (CH.sub.2), 70.0 (CH.sub.2), 49.5, 48.3 (C11, C12), 48.6 (C7), 31.5 (C10), 24.8 (C8), 22.6 (C9); .sup.19F NMR (376 MHz, D.sub.2O, δ.sub.F): −63.2 (s); HRMS (ESI.sup.+): calculated for C.sub.20H.sub.22F.sub.3N.sub.2O.sub.2: 379.1628, found [M+H.sup.+—HCl].sup.+: 379.1623.

Example 29a—N-Boc 4-Methyl cytisine (109)

(170) ##STR00057##

(171) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) in dry toluene (5.0 mL) was added Me.sub.4Sn (0.35 mL, 2.5 mmol). The mixture was stirred at 100° C. for 24 h under N.sub.2. The mixture was cooled to r.t., filtered through Celite,® washed with EtOAc (50 mL) and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (97:3)] to give 109 (308 mg, quantitative) as a pale yellow solid with few impurities.

(172) R.sub.f: 0.26 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.19 (s, 1H, C3-H), 5.87 (s, 1H, C5-H), 4.30-4.06 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.74 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.06-2.90 (m, 3H, C10-H, C11-H, C12-H), 2.35 (s, 1H, C8-H), 2.09 (s, 3H, Me), 1.94-1.85 (m, 2H, C9-H), 1.29-1.16 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.5 (CO), 154.7/154.3 (CO Boc, rotamers), 150.4/149.8 (C4, rotamers), 148.0/147.5 (C6, rotamers), 116.0 (C3), 108.3/107.6 (C5, rotamers), 80.4/79.7 (q Boc, rotamers), 51.8/50.7/50.5/49.4 (C11, C12, rotamers), 48.6 (C7), 34.8 (C10), 28.1 (3C, Boc), 27.6 (C8), 26.3 (C9), 21.2 (Me); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.25N.sub.2O.sub.3: 305.1860, found [M+H].sup.+: 305.1864, calculated for C.sub.17H.sub.24N.sub.2NaO.sub.3: 327.1679, found [M+Na].sup.+: 327.1684.

Example 29b—(−)4-Methylcytisine hydrochloride salt (110)

(173) ##STR00058##

(174) Following the general procedure A, N-Boc 4-Methylcytisine 109 (1.40 mmol) gave 110 (337 mg, quantitative) as a colourless solid.

(175) mp: >200° C., colourless powder; [α].sub.D.sup.26=−28 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2714, 2604, 2038, 1727, 1643, 1567; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.67 (s, 1H, C3-H), 6.59 (s, 1H, C5-H), 4.21 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.07 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.52-3.37 (m, 5H, C10-H, C11-H, C12-H), 2.83 (s, 1H, C8-H), 2.27 (s, 3H, Me), 2.16-2.13 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 163.3 (CO), 156.0 (C4), 146.5 (C6), 114.6 (C3), 114.5 (C5), 49.3 (C11 or C12), 49.0 (C7), 48.1 (C11 or C12), 31.2 (C10), 24.7 (C8), 22.4 (C9), 20.4 (Me); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.17N.sub.2O: 205.1335, found [M+H.sup.+—HCl].sup.+: 205.1336.

Example 30a—(−)N-Boc 4-Vinylcytisine (115)

(176) ##STR00059##

(177) A mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), 2,4,6-trivinylcyclotriboroxane pyridine complex (194 mg, 1.2 mmol), K.sub.2CO.sub.3 (276, 2.0 mmol) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) in dioxane/H.sub.2O (8:2) (5.0 mL) was stirred at 90° C. for 24 h under N.sub.2. The mixture was cooled to r.t., filtered through Celite,® and washed with EtOAc (50 mL). The organic layer was washed with water (10 mL), brine (10 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (97:3)] to give 115 (271 mg, 86%) as a pale yellow foam, which was used in the next step without further purification.

(178) R.sub.f: 0.22 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.44 (s, 1H, C14-H), 6.32 (s, 1H, C3-H), 6.14 (s, 1H, C5-H), 5.77 (d, 1H, J=17.5 Hz, C15-H.sub.A), 5.39 (d, 1H, J=11.0 Hz, C15-HB), 4.33-4.10 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.77 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.09-2.89 (m, 3H, C10-H, C11-H, C12-H), 2.38 (s, 1H, C8-H), 1.97-1.88 (m, 2H, C9-H), 1.30-1.15 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.8 (CO), 154.6/154.3 (CO Boc, rotamers), 148.6/148.2 (C6, rotamers), 147.1/146.9 (C4, rotamers), 134.8 (C14), 118.9 (C15), 114.7 (C3), 102.9/102.2 (C5, rotamers), 80.4/79.7 (q Boc, rotamers), 51.9/50.7/50.4/49.3 (C11, C12, rotamers), 48.8 (C7), 35.0 (C10), 28.1 (3C, Boc), 27.6 (C8), 26.3 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.25N.sub.2O.sub.3: 317.1860, found [M+H].sup.+: 317.1844, calculated for C.sub.18H.sub.24N.sub.2NaO.sub.3: 339.1679, found [M+Na].sup.+: 339.1665.

Example 30b—(+)4-Vinylcytisine hydrochloride salt (116)

(179) ##STR00060##

(180) Following the general procedure B, N-Boc-4-Vinyl-cytisine 115 (271 mg, 0.86 mmol) gave 116 (214 mg, 99%) as a colourless solid.

(181) mp: >200° C., colourless powder; [α].sub.D.sup.26=+18 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3376, 2938, 2717, 2574, 2386, 1643, 1552; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.82 (d, 1H, J=1.5 Hz, C3-H), 6.63-6.55 (m, 2H, C5-H, C14-H), 6.03 (d, 1H, J=17.5 Hz, C15-H.sub.A), 5.60 (d, 1H, J=11.0 Hz, C15-HB), 4.16 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.00 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.52-3.37 (m, 5H, C10-H, C11-H, C12-H), 2.83 (s, 1H, C8-H), 2.18-2.04 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.5 (CO), 150.3 (C4), 146.8 (C6), 133.2 (C14), 122.0 (C15), 113.2 (C5), 108.0 (C3), 49.4 (C11 or C12), 48.8 (C7), 48.1 (C11 or C12), 31.5 (C10), 24.7 (C8), 22.6 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.17N.sub.2O: 217.1335, found [M+H—HCl].sup.+: 217.1332.

Example 31a—N-Boc 4-Ethylcytisine (117)

(182) ##STR00061##

(183) To a solution of 4-vinyl-N-Boc-cytisine 115 (353 mg, 1.1 mmol) in methanol (22 mL) was added Pd/C 10% w/w (35 mg). The reaction vessel was placed under vacuum and backfilled with hydrogen three times. The mixture was stirred at r.t. for 24 h under 1 atm of H.sub.2. The mixture was filtered through Celite,® washed with EtOAc (50 mL) and concentrated in vacuo to give 117 (337 mg, 95%) as an off-white solid.

(184) R.sub.f: 0.17 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.22 (s, 1H, C3-H), 5.88 (s, 1H, C5-H), 4.33-4.30 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.74 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.05-2.91 (m, 3H, C10-H, C11-H, C12-H), 2.41-2.34 (m, 3H, C8-H, C14-H), 1.94-1.85 (m, 2H, C9-H), 1.28-1.14 (m, 12H, C15-H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 163.8 (CO), 156.0/155.5 (CO Boc, rotamers), 154.7/154.3 (C4, rotamers), 148.1/147.6 (C6, rotamers), 114.5 (C3), 107.3/106.4 (C5, rotamers), 80.3/79.7 (q Boc, rotamers), 51.7/50.7/50.5/49.3 (C11, C12, rotamers), 48.7 (C7), 34.8 (C10), 28.1 (3C, Boc), 27.6 (C8), 26.5 (C14), 26.3 (C9), 13.7/13.3 (C15, rotamers); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.27N.sub.2O.sub.3: 319.2016, found [M+H].sup.+: 319.2015, calculated for C.sub.18H.sub.26N.sub.2NaO.sub.3: 341.1836, found [M+Na].sup.+: 341.1840.

Example 31b—(−)4-Ethylcytisine hydrochloride salt (118)

(185) ##STR00062##

(186) Following the general procedure A, N-Boc-4-ethyl-cytisine 117 (0.92 mmol) gave 118 (227 mg, 97%) as a colourless solid.

(187) mp: >200° C., colourless powder; [α].sub.D.sup.26=−16 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2724, 2603, 1716, 1634, 1555; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.67 (d, 1H, J=1.5 Hz, C3-H), 6.57 (s, 1H, C5-H), 4.21 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.06 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.53-3.39 (m, 5H, C10-H, C11-H, C12-H), 2.83 (s, 1H, C8-H), 2.58 (q, 2H, J=7.5 Hz, C14-H), 2.17-2.06 (m, 2H, H.sub.9), 1.16 (t, 3H, J=7.5 Hz, C15-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 163.9 (CO), 161.1 (C4), 146.5 (C6), 113.5 (C5), 112.9 (C3), 49.4 (C11 or C12), 48.9 (C7), 48.1 (C11 or C12), 31.3 (C10), 27.7 (C14), 24.7 (C8), 22.5 (C9), 12.6 (C15); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.19N.sub.2O: 219.1492, found [M+H.sup.+—HCl].sup.+: 219.1494.

Example 32a—N-Boc 4-p-tolylcytisine (72)

(188) ##STR00063##

(189) A Schlenk tube was charged with N-Boc-4-bromo-cytisine 61 (370 mg, 1.0 mmol), potassium carbonate (250 mg, 1.8 eq.), tetrakis (triphenylphosphine) palladium (0) (58 mg, 5 mol %) and p-tolylboronic acid (160 mg, 1.2 eq. and a mixture of DME/water (5:1, 10 mL) was added. The reaction mixture was heated at 80° C. for 18 h. The solution was cooled and the solvent was removed in vacuo. The crude of the reaction was partitioned between water (15 mL) and DCM (15 mL), and the aqueous phase was extracted with DCM (3×15 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [DCM/MeOH (1.5% MeOH)] afforded 72 as a colourless solid. Recrystallization of the crude in hot toluene afforded 72 (260 mg, 71%) as a colourless foam.

(190) mp: 194-195° C., colourless foam (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2922, 1678, 1648, 1431; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 7.44 (d, 2H, J=8.0 Hz, Ar), 7.20 (d, 2H, J=8.0 Hz, Ar), 6.62 (s, 1H, C3-H), 6.28 (s, 1H, C5-H), 4.41-4.13 (m, 3H, C11-H, C12-H, C7-H), 3.83 (dd, 1H, J=15.0, 6.5 Hz, C7-H), 3.15-2.91 (m, 3H, C11-H, C12-H, C10-H), 2.39 (s, 1H, C8-H), 2.36 (s, 3H, Me), 1.99 (d, 1H, J=13.5 Hz, C9-H), 1.93 (d, 1H, J=13.5 Hz, C9-H), 1.23 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.5 (CO), 154.3 (CO), 150.5 (C3), 148.6 (C5), 139.2 (Ar), 134.9 (Ar), 129.5 (2C, Ar), 126.5 (2C, Ar), 113.2 (C3), 104.6 (C5), 79.8 (q Boc), 51.0, 50.6 (C11, C12), 48.6 (C7), 35.0 (C10), 28.0 (3C, Boc), 27.7 (C8), 26.4 (C9), 21.1 (Me); HRMS (ESI.sup.+): calculated for C.sub.23H.sub.29N.sub.2O.sub.3: 381.2173, found [M+H].sup.+: 381.2164; calculated for C.sub.23H.sub.28N.sub.2NaO.sub.3: 403.1992, found [M+Na].sup.+: 403.1984.

Example 32b—(+)4-p-Tolylcytisine (73)

(191) ##STR00064##

(192) In a schlenk flask N-Boc-4-p-tolyl-cytisine 72 (270 mg, 0.71 mmol) was dissolved in DCM (7.0 mL) and TFA (0.3 mL, 10 eq.) was added. The reaction mixture was stirred for 18 h at r.t. Then, water (10 mL) was added over the reaction mixture and the aqueous phase was washed with DCM (3×15 mL). Then, ammonia solution (20 mL, 15% aq. sol.) was added and the aqueous phase was extracted with DCM (3×15 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated, yielding 73 (140 mg, 74%) as a colourless solid. Recrystallization of the product in hot toluene afforded 73 (73 mg, 40%) as a colourless solid.

(193) mp: >200° C., colourless solid (toluene); [α].sub.D.sup.25=+44 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 1638, 1552, 1531; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 7.56 (d, 2H, J=8.0 Hz, Ar), 7.27 (d, 2H, J=8.0 Hz, Ar), 6.65 (d, 1H, J=2.0 Hz, C3-H), 6.58 (d, 1H, J=2.0 Hz, C5-H), 4.10 (d, 1H, J=15.5 Hz, C7-H), 3.93 (dd, 1H, J=15.5, 7.0 Hz, C7-H), 3.10-2.97 (m, 5H, C11-H, C12-H, C10-H), 2.38 (s, 3H, Me), 2.34 (s, 1H, C8-H), 2.01 (m, 2H, C9-H); .sup.13C NMR (125 MHz, MeOD, δ.sub.C): 164.5 (CO), 152.0 (C4), 151.4 (C6), 139.5 (Ar), 134.4 (Ar, 2C), 129.3 (Ar, 2C), 126.2 (Ar), 111.2 (C3), 105.6 (C5), 53.0, 51.9 (C11, C12), 49.5 (C7), 35.4 (C10), 27.6 (C8), 25.5 (C9), 19.7 (Me); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.21N.sub.2O: 281.1648, found [M+H].sup.+: 281.1653.

Example 33a—N-Boc 4-(N-2-pyridone)cytisine (107)

(194) ##STR00065##

(195) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), CuI (19 mg, 10 mol %), 2-hydroxypyridine (114 mg, 1.2 mmol) and K.sub.2CO.sub.3 (277 mg, 2.0 mmol) in dry toluene (5.0 mL) was added N,N′-dimethylethylenediamine (22 μL, 20 mol %). The mixture was heated at 110° C. for 24 h under nitrogen. More CuI (19 mg, 10 mol %) and N,N′-dimethylethylenediamine (DMEDA) (22 μL, 20 mol %) were added, and the stirring was carried on for 36 h. After cooling, the mixture was diluted with EtOAc (50 mL) then filtered through Celite.® The organic layer was washed with NH.sub.4OH (2×10 mL, 15% aq.sol.). The combined aqueous layers were extracted with DCM (5×10 mL). The combined organic layers (EtOAc and DCM) were dried on Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (95:5)] to give 107 (336 mg, 88%) as a pale yellow solid, which was used in the next step without further purification.

(196) R.sub.f: 0.17 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.37-7.33 (m, 1H, C17-H), 7.22 (d, 1H, J=6.0 Hz, C19-H), 6.57 (d, 1H, J=9.0 Hz, C16-H), 6.33-6.32 (m, 2H, C3-H, C5-H), 6.24-6.21 (m, 1H, C18-H), 4.36-4.15 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.76 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.04-2.98 (m, 3H, C10-H, C11-H, C12-H), 2.41 (s, 1H, C8-H), 2.04-1.90 (m, 2H, C9-H), 1.31-1.24 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.6 (CO py), 161.5 (CO), 154.7/154.4 (CO Boc, rotamers), 151.1 (C4), 149.7 (C6), 140.4 (C17), 136.7/136.2 (C19, rotamers), 122.3/122.0 (C16, rotamers), 113.0/112.7 (C3, rotamers), 106.7 (C18), 104.9/104.3 (C5, rotamers), 80.5/80.0 (q Boc, rotamers), 51.4/50.6/50.5/49.3 (C11, C12, rotamers), 49.1 (C7), 35.1 (C10), 28.1 (3C, Boc), 27.4 (C8), 26.0 (C9); HRMS (ESI.sup.+): calculated for C.sub.21H.sub.26N.sub.3O.sub.4: 384.1918, found [M+H].sup.+: 384.1921, calculated for C.sub.21H.sub.25N.sub.3NaO.sub.4: 406.1737, found [M+Na].sup.+: 406.1747.

Example 33b—(−)4-(N-2-pyridone)cytisine hydrochloride salt (108)

(197) ##STR00066##

(198) Following the general procedure B, N-Boc 4-(N-2-pyridone)-cytisine 107 (289 mg, 0.75 mol) gave 108 (182 mg, 76%) as a pale orange solid.

(199) mp: >200° C., colourless powder (toluene); [α].sub.D.sup.25=−20 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2922, 2710, 2601, 1662, 1638, 1595; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 7.74-7.70 (m, 1H, C17-H), 7.60 (dd, 1H, J=1.5, 7.0 Hz, C19-H), 6.69-6.62 (m, 4H, C3-H, C5-H, C16-H, C18-H), 4.23 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.07 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.57-3.40 (m, 5H, C10-H, C11-H, C12-H), 2.87 (s, 1H, C8-H), 2.20-2.10 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 165.1 (CO), 163.1 (CO py), 151.4 (C4), 148.8 (C6), 143.6 (C17), 137.3 (C19), 119.8 (C16), 114.3 (C3), 109.4 (C18), 108.0 (C5), 49.2 (C11 or C12), 48.9 (C7), 48.1 (C11 or C12), 31.7 (C10), 24.7 (C8), 22.4 (C9); HRMS(ESI.sup.+): calculated for C.sub.16H.sub.18N.sub.3O.sub.2: 284.1394, found [M+H—HCl].sup.+: 284.1388.

Example 34a—N-Boc 4-(trimethylsilylacetylene)cytisine (125)

(200) ##STR00067##

(201) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol), CuI (19 mg, 10 mol %) and PdCl.sub.2(PPh.sub.3).sub.2 (35 mg, 5 mol %) in dry THF (10.0 mL) was added i-Pr.sub.2NH (0.42 mL, 3.0 mmol) followed by trimethylsilylacetylene (0.16 mL, 1.1 mmol). The mixture was stirred at r.t. for 24 h under nitrogen. The mixture was diluted with DCM (50 mL). The organic layer was washed with NH.sub.4Cl (10 mL, sat. sol.), brine (10 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 125 (406 mg, quantitative) as a pale brown foam with few impurities (palladium catalyst). The product was used in the next step without further purification.

(202) R.sub.f: 0.21 [EtOAc]; FTIR v.sub.max/cm.sup.−1 (neat): 2972, 2932, 1689, 1651, 1574; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.48 (s, 1H, C3-H), 6.05 (s, 1H, C5-H), 4.32-4.09 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.78 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.08-2.92 (m, 3H, C10-H, C11-H, C12-H), 2.38 (s, 1H, C8-H), 1.96-1.88 (m, 2H, C9-H), 1.30-1.23 (m, 9H, Boc), 0.21 (s, 9H, C16-H); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.7 (CO), 154.4 (CO Boc), 148.8, 148.5 (C6, C4), 119.7 (C3), 107.9, 107.3 (C5, rotamers), 107.9 (C14), 100.2 (C15), 80.4, 79.9 (q Boc, rotamers), 51.5, 50.5, 50.3, 49.3 (C11, C12, rotamers), 48.8 (C7), 34.7 (C10), 28.0 (3C, Boc), 27.5 (C8), 26.1 (C9), −0.35 (3C, C16); HRMS (ESI.sup.+): calculated for C.sub.21H.sub.31N.sub.2O.sub.3Si: 387.2098, found [M+H].sup.+: 387.2094, calculated for C.sub.21H.sub.30N.sub.2NaO.sub.3Si: 409.1918, found [M+Na].sup.+: 409.1910.

Example 34b—A-Boc 4-(acetylene)cytisine 126

(203) ##STR00068##

(204) To a solution of N-Boc-4-(trimethylsilylacetylene)-cytisine 125 (379 mg, 0.98 mmol) in a mixture of MeOH (14 mL) and DCM (7 mL) was added K.sub.2CO.sub.3 (270 mg, 1.96 mmol). The mixture was stirred for 24 h. Water was added (10 mL) and the aqueous phase was extracted with DCM (3×20 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 126 (275 mg, 89%) as a white solid together with few impurities (palladium catalyst). The product was used in the next step without further purification.

(205) R.sub.f: 0.21 [EtOAc]; FTIR v.sub.max/cm.sup.−1 (neat): 3225, 2915, 2862, 1686, 1654, 1574; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 6.52 (s, 1H, C3-H), 6.06 (s, 1H, C5-H), 4.31-4.09 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.76 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.23 (s, 1H, C15-H), 3.04-2.93 (m, 3H, C10-H, C11-H, C12-H), 2.38 (s, 1H, C8-H), 1.96-1.88 (m, 2H, C9-H), 1.30-1.21 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.5 (CO), 154.4/154.3 (CO Boc, rotamers), 149.3, 148.8 (C6, C4), 120.3 (C3), 107.8/107.1 (C5, rotamers), 82.1 (C15), 80.8 (C14), 80.3/79.9 (q Boc, rotamers), 51.6/50.5/50.2/49.3 (C11, C12, rotamers), 48.9 (C7), 34.7 (C10), 28.0 (3C, Boc), 27.4 (C8), 26.0 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.23N.sub.2O.sub.3: 315.1703, found [M+H].sup.+: 315.1696, calculated for C.sub.18H.sub.22N.sub.2NaO.sub.3: 337.1523, found [M+Na].sup.+: 337.1516.

Example 34c—(−)4-(acetylenyl)cytisine hydrochloride salt (127)

(206) ##STR00069##

(207) Following the general procedure B, N-Boc 4-(acetylene)cytisine 126 (0.77 mmol) gave 127 (150 mg, 78%) as a pale yellow solid.

(208) mp: >200° C., pale yellow solid; [α].sub.D.sup.26=−32 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2726, 2604, 1631, 1540; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.55 (s, 1H, C3-H), 6.48 (s, 1H, C5-H), 4.00 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.86 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.74 (s, 1H, C15-H), 3.39-3.23 (m, 5H, C10-H, C11-H, C12-H), 2.70 (s, 1H, C8-H), 2.03-1.91 (m, 2H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.0 (CO), 147.4 (C4), 135.0 (C6), 119.8 (C3), 111.9 (C5), 85.2 (C15), 79.7 (C14), 49.3 (C11 or C12), 48.8 (C7), 48.1 (C11 or C12), 31.4 (C10), 24.7 (C8), 22.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.15N.sub.2O: 215.1179, found [M+H—HCl].sup.+: 215.1176.

Example 35a—N-Boc 4-(phenylacetylene)cytisine (128)

(209) ##STR00070##

(210) To a mixture of N-Boc 4-bromo cytisine 61 (369 mg, 1.0 mmol), CuI (38 mg, 20 mol %) and PdCl.sub.2(PPh.sub.3).sub.2 (70 mg, 10 mol %) in dry THF (5.0 mL) was added i-Pr.sub.2NH (0.42 mL, 3.0 mmol) followed by phenylacetylene (0.22 mL, 2.0 mmol). The mixture was stirred at r.t. for 24 h under nitrogen. The mixture was diluted with EtOAc (50 mL). The organic layer was washed with NH.sub.4Cl (10 mL, saturated solution), brine (10 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [EtOAc] to give 128 (376 mg, 96%) as a pale brown foam with few impurities (palladium catalyst). The product was used in the next step without further purification.

(211) R.sub.f: 0.14 [EtOAc]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.50-7.48 (m, 2H, C17-H), 7.34-7.33 (m, 3H, C18-H, C19-H), 6.56 (s, 1H, C3-H), 6.13 (s, 1H, C5-H), 4.34-4.12 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.79 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.05-2.96 (m, 3H, C10-H, C11-H, C12-H), 2.40 (s, 1H, C8-H), 1.98-1.89 (m, 2H, C9-H), 1.32-1.23 (m, 9H, Boc); .sup.13C NMR (100 MHz, CDCl.sub.3, δ.sub.C): 162.7 (CO), 154.4 (CO Boc), 148.9/148.5 (C6, rotamers), 134.0/133.7 (C4, rotamers), 131.8 (C17, C21), 129.1 (C19), 128.4 (C18, C20), 122.1 (C16), 119.2 (C3), 107.8/107.1 (C5, rotamers), 94.2 (C15), 86.6 (C14), 80.4/79.9 (q Boc, rotamers), 51.6/50.5/50.4/49.3 (C11, C12, rotamers), 48.8 (C7), 34.8 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.1 (C9); HRMS (ESI.sup.+): calculated for C.sub.24H.sub.27N.sub.2O.sub.3: 391.2016, found [M+H].sup.+: 391.2024, calculated for C.sub.24H.sub.26N.sub.2NaO.sub.3: 413.1836, found [M+Na].sup.+: 413.1876.

Example 35b—(+)4-(phenylacetylene)cytisine hydrochloride salt (129)

(212) ##STR00071##

(213) Following the general procedure B, N-Boc-4-(phenylacetylene)-cytisine 128 (0.88 mmol) gave 129 (267 mg, 92%) as a pale yellow solid.

(214) mp: >200° C., pale yellow solid; [α].sub.D.sup.26=+42 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2925, 2717, 2214, 1630, 1537; .sup.1H NMR (400 MHz, MeOH, δ.sub.H): 7.51-7.49 (m, 2H, C17-H), 7.41-7.33 (m, 3H, C18-H, C19-H), 7.00 (s, 1H, C3-H), 6.89 (s, 1H, C5-H), 4.33 (d, 1H, J=15.5 Hz, C7-H.sub.a), 4.17 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.56-3.22 (m, 5H, C10-H, C11-H, C12-H), 2.78 (s, 1H, C8-H), 2.17 (d, 1H, J=13.0 Hz, C9-H.sub.a), 2.07 (d, 1H, J=13.0 Hz, C9-H.sub.b); .sup.13C NMR (100 MHz, MeOD, δ.sub.C): 163.8 (CO), 150.3 (C6), 139.4 (C4), 133.2 (C17, C21), 131.4 (C19), 129.9 (C18, C20), 122.4 (C16), 117.5 (C5), 116.6 (C3), 99.4 (C15), 86.3 (C14), 51.4 (C7), 50.3 (C11, C12), 33.0 (C10), 26.4 (C8), 23.6 (C9); HRMS (ESI.sup.+): calculated for C.sub.19H.sub.19N.sub.2O: 291.1492, found [M+H—HCl]: 291.1486.

Example 36a—N-Boc 4-(E-2-propenoate methyl ester)cytisine (111)

(215) ##STR00072##

(216) To a mixture of N-Boc 4-bromocytisine 61 (369 mg, 1.0 mmol) and Pd.sub.2(dba).sub.3 (12 mg, 2.5 mol %) in dry dioxane (5.0 mL) was added Cy.sub.2NMe (0.2 mL, 1.1 mmol), P(t-Bu).sub.3 (0.1M in dioxane, 0.5 mL, 5 mol %) and ethyl acrylate (0.2 mL, 2.0 mmol). The mixture was stirred at r.t. for 24 h under nitrogen. Pd.sub.2(dba).sub.3 (12 mg, 2.5 mol %), P(t-Bu).sub.3 (0.1 M in dioxane, 0.50 mL, 5 mol %) and ethyl acrylate (0.2 mL, 2.0 mmol) were added again and the mixture stirred for 24 h more. The mixture was filtered through Celite,® washed with EtOAc and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (97:3)] to give 111 (321 mg, 83%) as a pale yellow solid.

(217) R.sub.f: 0.26 [DCM/MeOH (5% MeOH)]; mp: >200° C., colourless powder; FTIR v.sub.max/cm.sup.−1 (neat): 2973, 2934, 1723, 1679, 1655, 1640, 1567, 1431; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.35 (d, 1H, J=16.0 Hz, C14-H), 6.47 (s, 1H, C3-H), 6.38 (d, 1H, J=16.0 Hz, C15-H), 6.15 (s, 1H, C5-H), 4.34-4.07 (m, 5H, C7-H.sub.a, C11-H, C12-H, C17-H), 3.77 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.10-2.90 (m, 3H, C10-H, C11-H, C12-H), 2.39 (s, 1H, C8-H), 1.98-1.90 (m, 2H, C9-H), 1.31-1.14 (m, 12H, Boc, C18-H); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 165.9 (C16), 163.3 (CO), 154.5/154.2 (CO Boc, rotamers), 149.8/148.9 (C6, rotamers), 144.1/143.8 (C4, rotamers), 141.7 (C14), 123.1 (C15), 117.4 (C3), 102.9/102.0 (C5, rotamers), 80.4/79.8 (q Boc, rotamers), 60.9 (C17), 51.7/50.6/50.4/49.2 (C11, C12, rotamers), 49.0 (C7), 35.1 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.2 (C9), 14.2 (C18); HRMS (ESI.sup.+): calculated for C.sub.21H.sub.29N.sub.2O.sub.5: 389.2071, found [M+H].sup.+: 389.2059, calculated for C.sub.21H.sub.28N.sub.2NaO.sub.5: 411.1890, found [M+Na].sup.+: 411.1880.

Example 36b—(+)4-(E-2-propenoate methyl ester)cytisine hydrochloride salt (112)

(218) ##STR00073##

(219) Following the general procedure B, 111 (1.00 mmol) gave 112 (300 mg, 92%) as a pale yellow solid.

(220) mp: >200° C., pale yellow solid; [α].sub.D.sup.26=+22 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2943, 2751, 1706, 1655, 1637, 1570; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 7.28 (d, 1H, J=16.0 Hz, C14-H), 6.62 (d, 1H, J=1.5 Hz, C3-H), 6.47-6.43 (m, 2H, C5-H, C15-H), 4.11 (q, 2H, J=7.0 Hz, C17-H), 4.00 (d, 1H, J=16.0 Hz, C7-H.sub.a), 3.83 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.40-3.24 (m, 5H, C10-H, C11-H, C12-H), 2.69 (s, 1H, C8-H), 2.05-1.92 (m, 2H, C9-H), 1.16 (t, 3H, J=7.0 Hz, C18-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 167.9 (C16), 164.7 (CO), 147.2 (C4), 146.2 (C6), 141.1 (C14), 124.0 (C15), 116.9 (C3), 106.9 (C5), 62.1 (C17), 49.4 (C11 or C12), 48.7 (C7), 48.2 (C11 or C12), 31.6 (C10), 24.7 (C8), 22.6 (C9), 13.2 (C18); HRMS (ESI.sup.+): calculated for C.sub.16H.sub.21N.sub.2O.sub.3: 289.1547, found [M+H.sup.+—HCl].sup.+: 289.1561.

Example 37a—N-Boc-4-(E-(2-phenylethenyl))cytisine (113)

(221) ##STR00074##

(222) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and Pd.sub.2(dba).sub.3 (12 mg, 2.5 mol %) in dry dioxane (5.0 mL) was added Cy.sub.2NMe (0.2 mL, 1.1 mmol), P(t-Bu).sub.3 (0.1 M in dioxane, 0.50 mL, 5 mol %) and styrene (0.2 mL, 2.0 mmol). The mixture was stirred at r.t. for 24 h under nitrogen. Pd.sub.2(dba).sub.3 (12 mg, 2.5 mol %), P(t-Bu).sub.3 (0.1M in dioxane, 0.50 mL, 5 mol %) and styrene (0.2 mL, 2.0 mmol) were added again and the mixture stirred for 24 h more. The mixture was filtered through Celite®, washed with EtOAc and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (97:3)] to give 113 (373 mg, 95%) as a pale yellow foam. The product was used in the next step without further purification.

(223) R.sub.f: 0.19 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 7.49-7.47 (m, 2H, C17-H, C21-H), 7.36-7.25 (m, 3H, C18-H, C19-H, C20-H), 7.11 (d, 1H, J=16.0 Hz, C15-H), 6.81 (s, 1H, C14-H), 6.43 (s, 1H, C3-H), 6.28 (s, 1H, C5-H), 4.39-4.13 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.80 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.12-2.92 (m, 3H, C10-H, C11-H, C12-H), 2.39 (s, 1H, C8-H), 2.00-1.91 (m, 2H, C9-H), 1.37-1.17 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.8 (CO), 154.6/154.3 (CO Boc, rotamers), 148.5/148.1 (C6, rotamers), 147.0/146.7 (C4, rotamers), 136.1 (C16), 133.4/133.3 (C15, rotamers), 128.8 (C18, C20), 128.7 (C19), 127.0 (C17, C21), 126.0 (C14), 114.6 (C3), 103.1/102.3 (C5, rotamers), 80.3/79.7 (q Boc, rotamers), 51.8/50.6/50.5/49.3 (C11, C12, rotamers), 48.7 (C7), 35.0 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.3 (C9); HRMS (ESI.sup.+) calculated for C.sub.24H.sub.29N.sub.2O.sub.3: 393.2173, found [M+H].sup.+: 393.2173, calculated for C.sub.24H.sub.28N.sub.2NaO.sub.3: 415.1992, found [M+Na].sup.+: 415.1991.

Example 37b—(+)4-(E-(2-phenylethenyl))cytisine hydrochloride salt (114)

(224) ##STR00075##

(225) Following the general procedure B, 113 (0.88 mmol) gave 114 (259 mg, 89%) as an off-white solid.

(226) mp: >200° C., off-white solid; [α].sub.D.sup.26=+90 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2925, 2713, 2606, 1629, 1553; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 7.26-7.16 (m, 5H, C17-H, C18-H, C19-H), 6.99 (d, 1H, J=16.5 Hz, C15-H), 6.59 (d, 1H, J=16.5 Hz, C14-H), 6.51 (s, 1H, C3-H), 6.23 (s, 1H, C5-H), 3.87 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.54 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.31-3.16 (m, 5H, C10-H, C11-H, C12-H), 2.56 (s, 1H, C8-H), 1.91 (d, 1H, J=13.5 Hz, C9-H), 1.67 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.1 (CO), 149.8 (C16), 146.3 (C6), 135.4 (C15), 135.3 (C14), 129.2 (C19), 128.8 (C18, C20), 127.2 (C17, C21), 124.3 (C4), 113.1 (C3), 107.7 (C5), 49.5 (C11 or C12), 48.5 (C7), 48.1 (C11 or C12), 31.4 (C10), 24.6 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.19H.sub.21N.sub.2O: 293.1648, found [M+H—HCl].sup.+: 293.1655.

Example 38a—N-Boc 4-(1-(4-phenyl)-NH-1,2,3-triazolyl)cytisine (134)

(227) ##STR00076##

(228) To a mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.00 mmol), NaN.sub.3 (130 mg, 2.0 mmol), sodium ascorbate (20 mg, 10 mol %) and CuI (19 mg, 10 mol %) in EtOH/H.sub.2O (7:3) (5.0 mL) was added DMEDA (22 μL, 20 mol %) then phenylacetylene (132 μL, 1.2 mmol). The mixture was stirred at 50° C. for 24 h under nitrogen. The mixture was cooled to r.t., diluted with NH.sub.4OH solution (20 mL, 15% aq.sol.) and then extracted with EtOAc (3×50 mL). The combined organic layers were washed with brine (20 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude (86-93% conversion based on .sup.1H NMR) was purified by flash column chromatography on silica gel [EtOAc then DCM/MeOH/NH.sub.4OH (97:3:0.1)] to give 134 (214 mg, 49%) as an off-white solid, which was used in the next step without further purification.

(229) R.sub.f: 0.11 [EtOAc]; 1H NMR (400 MHz, CDCl.sub.3, δ.sub.H): 8.22 (s, 1H, C14-H), 7.89 (d, 2H, J=7.0 Hz, C17-H, C21-H), 7.47-7.44 (m, 2H, C18-H, C20-H), 7.39-7.36 (m, 1H, C19-H), 6.91 (s, 1H, C3-H), 6.70 (s, 1H, C5-H), 4.39-4.20 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.87 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.15-3.00 (m, 3H, C10-H, C11-H, C12-H), 2.47 (s, 1H, C8-H), 2.06-1.98 (m, 2H, C9-H), 1.34-1.19 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.3 (CO), 154.6 (CO Boc), 152.0/151.5 (C6, rotamers), 149.0 (C15), 145.0 (C4), 129.7 (C16), 129.1 (C18, C20), 128.9 (C19), 126.1 (C17, C21), 116.9 (C14), 103.8 (C5), 98.3/97.8 (C3, rotamers), 80.7/80.1 (q Boc, rotamers), 51.6/50.8/50.3/49.4 (C11, C12, rotamers), 49.3 (C7), 35.5 (C10), 28.2 (3C, Boc), 27.5 (C8), 26.1 (C9); HRMS (ESI.sup.+): calculated for C.sub.24H.sub.27N.sub.5NaO.sub.3: 456.2006, found [M+Na].sup.+: 456.1993.

Example 38b—(+)4-(1-(4-phenyl)-NH-1,2,3-triazolyl)cytisine dihydrochloride salt (135)

(230) ##STR00077##

(231) Following the general procedure B, N-Boc-4-((4-phenyl)-NH-1, 2, 3, triazole)-cytisine 134 (0.46 mmol) gave 135 (151 mg, 81%) as a colourless solid.

(232) mp: >200° C., colourless powder; [α].sub.D.sup.22=+36 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 3436, 3034, 2565, 1656, 1563; .sup.1H NMR (400 MHz, DMSO-d6, δ.sub.H): 9.50 (s, 1H, C14-H), 8.58 (s, 1H, NH), 7.94 (d, 2H, J=7.5 Hz, C17-H, C21-H), 7.50 (app t, 2H, J=7.5 Hz, C18-H, C20-H), 7.40 (app t, 1H, J=7.5 Hz, C19-H), 7.10 (d, 1H, J=2.5 Hz, C3-H), 6.93 (d, 1H, J=2.5 Hz, C5-H), 4.01 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.85 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.46 (s, 1H, C10-H), 3.35-3.16 (m, 4H, C11-H, C12-H), 2.67 (s, 1H, C8-H), 2.07 (d, 1H, J=13.0 Hz, C9-H), 1.94 (d, 1H, J=13.0 Hz, C9-H); .sup.13C NMR (100 MHz, DMSO-d6, δ.sub.C): 162.7 (CO), 150.2 (C4), 147.8 (C15), 144.4 (C6), 129.7 (C19), 129.1 (C18, C20), 128.6 (C16), 125.5 (C17, C21), 119.5 (C14), 103.8 (C5), 97.6 (C3), 48.4 (C11 or C12), 48.1 (C7), 47.4 (C11 or C12), 31.6 (C10), 24.5 (C8), 22.7 (C9); HRMS (ESI.sup.+): calculated for C.sub.19H.sub.20N.sub.5O: 334.1662, found [M+H.sup.+-2HCl].sup.+: 334.1676; calculated for C.sub.19H.sub.19N.sub.5NaO: 356.1482, found [M+Na-2HCl].sup.+: 356.1503.

Example 39a—N-Boc 4-(1,2,3-triazol-1-yl)methyl pivalate)cytisine (131)

(233) ##STR00078##

(234) To a solution of N-Boc-4-(acetylene)-cytisine 126 (544 mg, 1.73 mmol) in a mixture of tBuOH/H.sub.2O (1:1) (8.6 mL) were successively added azidomethyl pivalate (0.3 mL, 2.08 mmol), CuSO.sub.4.Math.5H.sub.2O (22 mg, 5 mol %) and sodium ascorbate (102 mg, 30 mol %). The mixture was stirred at r.t. for 48 h. The mixture was diluted with NH.sub.4OH (10 mL, 15% aq. sol.) then extracted with EtOAc (3×20 mL). The combined organic layers were washed with brine (20 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (95:5:0.1)] to give 131 (722 mg, 89%) with few impurities as a pale yellow oil, which was used in the next step without further purification.

(235) R.sub.f: 0.08 [DCM/MeOH (5% MeOH)]; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 8.07 (s, 1H, C15-H), 6.78-6.72 (m, 2H, C3-H, C5-H), 6.26 (s, 2H, C16-H), 4.37-4.16 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.84 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.08-2.95 (m, 3H, C10-H, C11-H, C12-H), 2.43 (s, 1H, C8-H), 2.02-1.94 (m, 2H, C9-H), 1.32-1.13 (m, 18H, Boc, C19-H); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 178.0 (C17), 163.5 (CO), 154.7/154.5 (CO Boc, rotamers), 150.1/149.5 (C4, rotamers), 145.5 (C14), 140.1/139.9 (C6, rotamers), 123.2/123.0 (C15, rotamers), 112.4 (C3), 103.5/102.9 (C5, rotamers), 80.5/79.9 (q Boc, rotamers), 69.9 (C16), 51.7/50.8/50.4/49.4 (C11, C12, rotamers), 49.0 (C7), 38.9 (C18), 35.1 (C10), 28.2 (3C, Boc), 27.7 (C8), 26.9 (3C, C19), 26.3 (C9); HRMS (ESI.sup.+): calculated for C.sub.24H.sub.34N.sub.5O.sub.5: 472.2554, found [M+H].sup.+: 472.2551; calculated for C.sub.24H.sub.33N.sub.5NaO.sub.5: 494.2374, found [M+Na].sup.+: 494.2371.

Example 39b—N-Boc4-(NH-1,2,3-triazolyl))-cytisine (132)

(236) ##STR00079##

(237) To a solution of N-Boc-4-(1,2,3-triazol-1-yl)methyl pivalate)-cytisine 131 (688 mg, 1.46 mmol) in MeOH (3.2 mL) was added NaOH (3.2 mL, 1M aq. sol.). The mixture was stirred at r.t. for 12 h. The reaction was neutralized with HCl (3.2 mL, 1M aq. sol.), diluted with water (30 mL) and extracted with EtOAc (5×20 mL). The combined organic layers were washed with brine (20 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH/NH.sub.4OH (97:3:0.1)] to give 132 (461 mg, 88%) as an off-white solid.

(238) R.sub.f: 0.32 [DCM/MeOH (10% MeOH)]; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 8.01-7.82 (m, 1H, C15-H), 7.03-6.92 (m, 1H, C3-H), 6.77 (s, 1H, C5-H), 4.39-4.15 (m, 3H, C7-H.sub.a, C11-H, C12-H), 3.91 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.15-2.99 (m, 3H, C10-H, C11-H, C12-H), 2.47 (s, 1H, C8-H), 2.06-1.97 (m, 2H, C9-H), 1.36-1.14 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 164.0 (CO), 155.0/154.7 (CO Boc, rotamers), 149.9/149.1 (C4, rotamers), 143.6 (C14), 141.2 (C6), 128.7/128.3 (C15, rotamers), 112.4 (C3), 104.7/104.2 (C5, rotamers), 81.3/80.1 (q Boc, rotamers), 51.8/50.9/50.8/49.5 (C11, C12, rotamers), 49.2 (C7), 35.2 (C10), 28.2 (3C, Boc), 27.3 (C8), 26.3 (C9); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.24N.sub.5O.sub.3: 358.1874, found [M+H].sup.+: 358.1874; calculated for C.sub.18H.sub.23N.sub.5NaO.sub.3: 380.1693, found [M+Na].sup.+: 380.1703.

Example 39c—(+)4-(NH-1,2,3-triazolyl))cytisine dihydrochloride salt 133 (A)

(239) ##STR00080##

(240) Following the general procedure A, N-Boc-4-(NH-1,2,3-triazole)-cytisine 132 (1.22 mmol) was deprotected and converted into the HCl salt using the general procedure A yielding 133 (352 mg, 87%) as an colourless solid.

(241) mp: >200° C., colourless powder; [α].sub.D.sup.22=+32 [c 0.5, water]; FTIR v.sub.max/cm.sup.−1 (neat): 3094, 2905, 2723, 2396, 1651, 1552; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 8.19 (s, 1H, C15 H), 6.81 (d, 1H, J=1.5 Hz, C3-H), 6.68 (d, 1H, J=1.5 Hz, C5-H), 4.13 (d, 1H, J=15.5 Hz, C7-H.sub.a), 3.90 (dd, 1H, J=6.5, 15.5 Hz, C7-H.sub.b), 3.54-3.38 (m, 5H, C10-H, C11-H, C12-H), 2.83 (s, 1H, C8-H), 2.16 (d, 1H, J=13.5 Hz, C9-H), 2.05 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 164.2 (CO), 147.9 (C6), 142.1 (C14), 141.5 (C4), 125.4 (C15), 111.2 (C5), 107.0 (C3), 49.3 (C11 or C12), 48.7 (C7), 48.2 (C11 or C12), 31.6 (C10), 24.7 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.13H.sub.16N.sub.5O: 258.1349, found [M+H.sup.+-2HCl].sup.+: 258.1342; calculated for C.sub.13H.sub.15N.sub.5NaO: 280.1169, found [M+Na-2HCl].sup.+: 280.1163.

Example 40—(+)4-(N-ethylamino)cytisine (87)

(242) ##STR00081##

(243) A mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and copper (7 mg, 10 mol %) in EtNH.sub.2 (2.0 mL, 2.0 M in THF) was stirred in water (1 mL) at 100° C. for 24 h in a sealed tube. The mixture was cooled and extracted with DCM (5×10 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (6% MeOH)] to give 87 (102 mg, 42%) as an off-white solid.

(244) Mp: ≥200° C.; [α].sub.D.sup.23=+50 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3269, 2901, 2868, 1639, 1532; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 5.92 (d, 1H, J=2.0 Hz, C3-H), 5.54 (d, 1H, J=2.0 Hz, C5-H), 3.92 (d, 1H, J=15.0 Hz, C7-H), 3.79 (dd, 1H, J=6.0, 15.0 Hz, C7-H), 3.13 (q, 2H, J=7.5 Hz, CH.sub.2), 3.06-2.90 (m, 5H, C10-H, C11-H, C12-H), 2.33 (s, 1H, C8-H), 1.98 (d, 1H, J=13.5 Hz, C9-H), 1.91 (d, 1H, J=13.5 Hz, C9-H), 1.10 (t, 3H, J=7.5 Hz, CH.sub.3); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 165.3 (CO), 157.1 (C4), 150.7 (C6), 99.5 (C3), 89.4 (C5), 52.0, 50.8 (C11, C12), 48.9 (C7), 36.8 (CH.sub.2), 34.5 (C10), 26.8 (C8), 24.9 (C9), 13.0 (CH.sub.3); HRMS (ESI.sup.+): calculated C.sub.13H.sub.20N.sub.3O: 234.1601, found [M+H].sup.+: 234.1609.

Example 41—(+)4-(N-isopropylamino)cytisine 88

(245) ##STR00082##

(246) A mixture of N-Boc-4-bromo-cytisine 61 (369 mg, 1.0 mmol) and copper (7 mg, 10 mol %) in 40% aq. iPrH.sub.2 (2.0 mL) was stirred at 100° C. for 24 h in a sealed tube. The mixture was cooled and extracted with DCM (5×10 mL). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (6% MeOH)] to give 88 (88 mg, 33%) as an off-white solid.

(247) Mp: ≥200° C.; [α].sub.D.sup.24=+50 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2969, 1639, 1535, 1276; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 5.76 (d, J=2.5 Hz, 1H, C3-H), 5.46 (d, J=2.5 Hz, 1H, C5-H), 3.97 (d, J=15.0 Hz, 1H, C7-H), 3.79 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.57 (hept, J=6.5 Hz, 1H, C13-H), 3.07-2.92 (m, 4H, C11-H C12-H), 2.83 (s, 1H, C10-H), 2.27 (s, 1H, C8-H), 1.95 (m, 2H, C9-H), 1.20 (dd, J=6.5, 2.0 Hz, 6H, C14-H); .sup.13C NMR (125 MHz, MeOD, δ.sub.C): 165.5 (CO), 155.7 (C4), 149.7 (C6), 98.7 (C3), 89.1 (C5), 52.7, 51.6 (C11 C12), 48.5 (C7), 43.1 (C13), 35.1 (C10), 27.6 (C8), 25.6 (C9), 21.0 (2C, C14); HRMS (ESI.sup.+): calculated C.sub.14H.sub.22N.sub.3O: 248.1757, found [M+H.sup.+—HCl].sup.+: 248.1766.

Example 42a—N-Boc 4-cyanocytisine (139)

(248) ##STR00083##

(249) A Schlenk tube was charged with N-Boc-4-bromo-cytisine 61 (1.85 g, 5.00 mmol), Pd((PPh.sub.3).sub.4) (230 mg, 0.20 mmol), and zinc cyanide (350 mg, 3.00 mmol), and placed under nitrogen. DMF (6.2 mL) was added and the reaction mixture was heated at 80° C. for 18 h. The reaction mixture was cooled and the solvent was removed in vacuo. Purification of the crude reaction mixture by flash column chromatography [DCM:MeOH (1% MeOH)] afforded 139 (1.6 g, 99%) as a colourless solid.

(250) R.sub.f: 0.7 [DCM/MeOH (4% MeOH)]; mp: 153-156° C., colourless powder (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2973, 2233 (weak peak as conjugated, CN band), 1658, 1572; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H, 52.0° C.): 6.74 (s, 1H, C3-H), 6.18 (s, 1H, C5-H), 4.42-4.07 (m, 3H, C11-H, C12-H, C7-H), 3.81 (dd, 1H, J=6.5, 16.0 Hz, C7-H), 3.19-2.91 (m, 3H, C11-H, C12-H, C10-H), 2.48 (s, 1H, C8-H), 1.98 (s, 2H, C9-H), 1.38-1.17 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C, 52.0° C.): 161.3 (CO), 154.1 (C4), 151.7 (C6), 121.9 (C3), 115.9 (CN), 104.3 (C5), 80.5 (q Boc), 50.1, 49.8 (C11, C12), 49.2 (C7), 34.8 (C10), 28.4 (3C, Boc), 27.4 (C8), 25.8 (C9). (Carbonyl carbon of the Boc group not observed); HRMS (ESI.sup.+): calculated C.sub.17H.sub.21N.sub.3NaO: 338.1475, found [M+Na].sup.+: 338.1467.

Example 43—(−)4-Cyanocytisine (140)

(251) ##STR00084##

(252) In a Schlenk flask, N-Boc-4-cyano-cytisine 139 (140 mg, 0.46 mmol) was dissolved in DCM (3.0 mL, 0.1 M) and TFA (0.3 mL, 10 eq.) was added. The solution was stirred at r.t. for 16 h. Water was added (10 mL) and the aqueous phase was washed with DCM (3×20 mL). Ammonia was added (10 mL, 15% aq. sol.) and the aqueous phase was extracted with DCM (4×20 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated, yielding 140 (86 mg, 86%) as a colourless solid.

(253) mp: 161-163° C., colourless needles (toluene); [α].sub.D.sup.23=−53 [c 0.66, MeOH]; (FTIR v.sub.max/cm.sup.−1 (neat): 2233 (weak peak as conjugated, CN band), 1649, 1581; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 6.87 (d, 1H, J=2.0 Hz, C3-H), 6.59 (d, 1H, J=2.0 Hz, C5-H), 4.19 (d, 1H, J=16.0 Hz, C7-H), 4.01 (dd, 1H, J=16.0, 7.0 Hz, C7-H), 3.52-3.35 (m, 5H, C10-H, C11-H, C12-H), 2.78 (s, 1H, C8-H), 2.18 (d, 1H, J=14.0 Hz, C9-H), 2.10 (d, 1H, J=14.0 Hz, C9-H); .sup.13C NMR (125 MHz, MeOD, δ.sub.C): 161.6 (C2), 154.1 (C6), 122.7 (C4), 121.4 (C3), 116.4 (C13), 104.1 (C5), 53.7, 52.9 (C11, C12), 50.4 (C7), 35.7 (C10), 27.5 (C8), 25.9 (C9); HRMS (ESI.sup.+): calculated C.sub.12H.sub.14N.sub.3O: 216.1131, found [M+H].sup.+: 216.1129.

Example 44a—N-Boc-4-(carboxyamido)cytisine (141)

(254) ##STR00085##

(255) To a solution of N-Boc-4-cyano-cytisine 139 (320 mg, 1.0 mmol) in an equimolar mixture of EtOH/water (5 mL) was added NaBH.sub.4 (33 mg, 0.75 mmol) and the reaction mixture was stirred at 75° C. for 18 h. The reaction mixture was cooled to r.t., and quenched with water (5 mL). Ethanol was removed in vacuo. Then, the aqueous phase was extracted with DCM (3×15 mL) and the combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [DCM/MeOH (from 2% to 4% MeOH)] yielded 141 (150 mg, 46%) as a colourless solid which was recrystallized from toluene.

(256) R.sub.f: 0.43 [DCM/MeOH (4% MeOH)]; mp: >200° C., colourless powder; FTIR v.sub.max/cm.sup.−1 (neat): 3317, 3148, 2974, 1690, 1639, 1562; .sup.1H NMR (500 MHz, MeOD, 5H, 52° C.): 6.83 (s, 1H, C3-H), 6.69 (s, 1H, C5-H), 4.35-4.31 (s, 1H, C11-H), 4.20-4.16 (br s, 1H, C7-H), 4.14 (s, 1H, C12-H), 3.84 (dd, 1H, J=6.0, 15.0 Hz, C7-H), 3.27-2.98 (m, 3H, C10-H C11-H C12-H), 2.49 (s, 1H, C8-H), 2.12-1.97 (m, 2H, C9-H), 1.41-1.06 (s, 9H, Boc); .sup.13C NMR (125 MHz, MeOD, δ.sub.C, 52° C.): 167.8 (CO amide), 163.4 (CO pyridone), 154.6 (CO Boc), 150.8 (C6), 144.4 (C4), 114.3 (C3), 104.6 (C5), 80.2 (q Boc), 67.4 (C11, C12), 49.3 (C7), 35.2 (C10), 27.7 (C8), 26.9 (3C, Boc), 25.1 (C9); HRMS (ESI.sup.+): calculated C.sub.17H.sub.24N.sub.3O.sub.4: 334.1761, found [M+H].sup.+: 334.1753; calculated C.sub.17H.sub.23N.sub.3NaO.sub.4: 356.1581, found [M+Na].sup.+: 356.1570.

Example 44b—(−)4-(carboxyamido)cytisine hydrochloride salt (142)

(257) ##STR00086##

(258) Following the general procedure A, N-Boc-4-amido-cytisine 141 (0.44 mmol) gave 142 (90 mg, 88%) as a colourless solid.

(259) mp: >200° C., colourless powder; [α].sub.D.sup.25=−2 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 1646, 1543; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 6.92 (d, 1H, J=2.0 Hz, C3-H), 6.75 (d, 1H, J=2.0 Hz, C3-H), 4.21 (d, 1H, J=16.0 Hz, C7-H), 4.05 (dd, 1H, J=16.0, 6.5 Hz, C7-H), 3.53-3.41 (m, 5H, C11-H, C12-H, C10-H), 2.82 (s, 1H, C8-H), 2.20 (d, 1H, J=13.5 Hz, C9-H), 2.12 (d, 1H, J=13.5 Hz, C9-H); .sup.13C NMR (125 MHz, MeOD, δ.sub.C): 167.7 (CO CONH.sub.2), 164.1 (CO), 147.4 (C4), 144.8 (C6), 115.8 (C3), 105.3 (C5), 49.4 (C7), 32.1 (C10), 25.2 (C8), 22.8 (C9), (C11 and C12 are under the signal of the solvent); HRMS (ESI.sup.+): calculated C.sub.12H.sub.16N.sub.3O.sub.2: 234.1237, found [M+H—HCl].sup.+: 234.1229.

Example 45a—N-Boc 4-(Aminomethyl)cytisine (143)

(260) ##STR00087##

(261) Raney Ni (0.3 mL, slurry in water) was added over a solution of N-Boc-4-cyano-cytisine 139 (320 mg, 1.0 mmol) and KOH (84 mg, 1.5 mmol) in EtOH (10 mL, 0.1 M). The reaction vessel was placed under vacuum and backfilled with hydrogen three times, and stirred at r.t. for 18 h. The reaction mixture was filtered through Celite® and the crude reaction mixture was concentrated. Purification by flash column chromatography [DCM:MeOH (10% MeOH)+0.1% ammonia (35% aq. sol.)] yielded amine 143 (260 mg, 82%) as a colourless solid.

(262) R.sub.f: 0.22 [DCM:MeOH (10% MeOH)]; mp: 157-160° C., colourless powder (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2928, 1673, 1644, 1542; .sup.1H NMR (500 MHz, MeOD, 5H, 52° C.): 6.40 (s, 1H, C3-H), 6.34 (d, 1H, J=2.0 Hz, C5-H), 4.27 (s, 1H, C11-H), 4.16 (s, 1H, C12-H), 4.12 (s, 1H, C7-H), 3.30 (dd, 1H, J=6.0, 15.0 Hz, C7-H), 3.67 (s, 2H, C13-H), 3.22-3.04 (m, 3H, C11-H, C12-H, C10-H), 2.45 (s, 1H, C8-H), 2.08-1.99 (m, 2H, C9-H), 1.42-1.11 (s, 9H, Boc); .sup.13C NMR (125 MHz, MeOD, 5c, 52° C.): 164.3 (CO), 155.6 (CO), 154.7 (C6), 149.3 (C4), 112.3 (C3), 106.5 (C5), 79.97 (q Boc), 50.3 (C11, C12), 48.9 (C7), 44.1 (C13), 34.9 (C10), 27.7 (C8), 27.0 (3C, Boc), 25.4 (C9); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.25N.sub.3O.sub.3: 319.1896, found [M+H].sup.+: 320.1958, calculated for C.sub.17H.sub.24N.sub.3NaO.sub.3: 342.1794, found [M+Na].sup.+: 342.1783.

Example 45b—(−)4-(aminomethyl)cytisine dihydrochloride salt (144)

(263) ##STR00088##

(264) Following the general procedure A, N-Boc-4-methylamino-cytisine 143 (0.76 mmol) was converted into the HCl salt yielding 144 (150 mg, 89%) as a colourless solid.

(265) mp: >200° C., colourless powder; [α].sub.D.sup.26=−46 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2789, 1653, 1518; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.50 (s, 1H, C3-H), 6.46 (s, 1H, C5-H), 4.07 (d, 1H, J=16.0 Hz, C7-H), 4.02 (s, 2H, C13-H), 3.94 (dd, 1H, J=16.0, 6.5 Hz, C7-H), 3.45-3.29 (m, 5H, C11-H, C12-H, C8-H), 2.75 (s, 1H, C10-H), 2.06 (d, 1H, J=13.6 Hz, C9-H), 2.00 (d, 1H, J=13.6 Hz, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.6 (CO), 148.0 (C4), 16.9 (C6), 115.4 (C3), 108.5 (C5), 48.7 (C7), 49.3, 48.2 (C11, C12), 41.2 (C13), 31.5 (C8), 24.8 (C10), 22.4 (C9); HRMS (ESI.sup.+): calculated C.sub.12H.sub.18N.sub.3O: 220.1444, found [M+H—HCl].sup.+: 220.1441.

Example 46a—N-Boc 4-(N-Boc aminomethyl)cytisine

(266) ##STR00089##

(267) To a solution of N-Boc-4-aminomethyl-cytisine 143 (264 mg, 0.83 mmol) in THF (8 mL) were added Boc.sub.2O (0.2 mL, 0.91 mmol) and triethylamine (0.16 mL, 1.16 mmol), and the reaction mixture was stirred for 18 h at r.t. Then, water (15 mL) was added and the aqueous phase was extracted with DCM (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered, and concentrated. Purification by flash column chromatography [DCM:MeOH (3% MeOH)] yielded N-Boc-4-(N-Boc-aminomethyl)-cytisine (280 mg, 82%) as a colourless oil.

(268) FTIR v.sub.max/cm.sup.−1 (neat): 3316, 2975, 1683, 1653, 1546, 1423; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H, 52° C.): 6.33 (s, 1H, C3-H), 5.98 (d, 1H, J=2.0 Hz, C5-H), 4.82 (s, 1H, NH), 4.36-4.07 (m, 5H, C7-H, C11-H, C12-H, C13-H), 3.81 (dd, 1H, J=5.5, 15.5 Hz, C7-H), 3.10-2.94 (m, 3H, C11-H, C12-H, C10-H), 2.41 (s, 1H, C8-H), 1.99 (d, 1H, J=13.5 Hz, C9-H), 1.92 (d, 1H, J=13.5 Hz, C9-H), 1.46 (s, 9H, Boc), 1.38-1.23 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C, 52° C.): 166.4 (CO), 155.8 (CO Boc), 154.5 (CO Boc), 150.9 (C6), 148.7 (C4), 113.8 (C3), 104.4 (C5), 79.6 (2C, q Boc), 50.8, 50.5 (C11, C12), 48.7 (C7), 43.5 (C13), 35.0 (C10), 28.3, 28.0 (6C, Boc), 27.6 (C8), 26.3 (C9); HRMS (ESI.sup.+): calculated for C.sub.22H.sub.34N.sub.3O.sub.5: 420.2492, found [M+H].sup.+: 420.2490.

Example 46b—(−)4-((N-methyl)aminomethyl)cytisine (152)

(269) ##STR00090##

(270) To a solution of N-Boc-4-(N-Boc-aminomethyl)-cytisine (255 mg, 0.61 mmol) in THF (6.0 mL) was added NaH (17 mg, 0.70 mmol, 60% dispersion oil) and the solution was stirred for 30 min. Iodomethane (0.05 mL, 0.70 mmol) was added and the reaction mixture was stirred for 18 h at r.t. The crude was distributed between water (10 mL) and EtOAc (10 mL) and the aqueous phase was extracted with EtOAc (3×10 mL). The combined organic phases were dried over MgSO.sub.4, filtered, and concentrated. The resulting compound was deprotected and converted into its HCl salt using the general procedure A, yielding 152 (89 mg, 65%) as a colourless solid.

(271) mp: >200° C.; FTIR v.sub.max/cm.sup.−1 (neat): 2728, 1651, 1548; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.57 (s, 1H, C3-H), 6.51 (s, 1H, C5-H), 4.14-4.05 (m, 3H, C7-H, CH.sub.2), 3.97 (dd, J=6.0, 15.5 Hz, 1H, C7-H), 3.50-3.31 (m, 5H, C10-H, C11-H, C12-H), 2.79 (s, 1H, C10-H), 2.70 (s, 3H, NHMe), 2.13-2.00 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.5 (CO), 148.3 (C6), 145.0 (C4), 117.2 (C3), 109.1 (C5), 50.4 (CH.sub.2), 49.4, 48.1 (C11, C12), 48.7 (C7), 32.6 (NHMe), 31.7 (C10), 24.8 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated C.sub.13H.sub.20N.sub.3O: 234.1601, found [M+H—HCl].sup.+: 234.1595.

Example 47a—Tert-butyl (1R,5R)-10-(hydroxymethyl)-8-oxo-1,5,6,8-tetrahydro-2H-1,5-methanopyrido[1,2-a][1,5]diazocine-3(4H)-carboxylate (153)

(272) ##STR00091##

(273) N-Boc-4-cyano-cytisine 139 (200 mg, 0.63 mmol) was dissolved in a mixture of pyridine, acetic acid and water in a proportion (2:1:1) and NaH.sub.2PO.sub.2 (340 mg, 3.27 mmol) and Ni Raney (1.0 mL, slurry in water) were added. The reaction mixture was stirred at 50° C. for 6 h. The solution was filtered through Celite® and concentrated. The crude was distributed between water (15 mL) and DCM (15 mL) and the aqueous phase was extracted with DCM (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by column chromatography [DCM/MeOH (4% MeOH)] yielded 153 (170 mg, 86%) as a colourless pale-yellow solid.

(274) R.sub.f: 0.10 [DCM/MeOH (4% MeOH)]; mp: 75-78° C., pale-yellow solid (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 2928, 1651, 1543, 1423; .sup.1H NMR (500 MHz, MeOD, δ.sub.H, 52° C.): 6.44 (s, 2H, C3-H), 6.39 (d, 2H, J=2.0 Hz, C5-H), 4.31 (m, 6H, C11-H, C12-H, NH), 4.15 (d, 2H, J=15.0 Hz, C7-H), 3.80 (dd, 2H, J=15.0, 6.5 Hz, C7-H), 3.64 (s, 4H, C14-H), 3.13 (s, 5H, C10-H, C11-H, C12-H), 2.45 (s, 2H, C8-H), 2.05 (m, 4H, C9-H), 1.28 (s, 18H, Boc); .sup.13C NMR (125 MHz, MeOD, δ.sub.C, 52° C.): 164.1 (2×CO), 157.7 (2×CO), 153.3 (2×C4), 149.7 (2×C6), 113.6 (2×C3), 107.3 (2×C5), 80.0 (2×q Boc), 50.8, 50.7 (4×C11, C12), 50.6 (2×C14), 48.8 (2×C7), 35.0 (2×C10), 27.7 (2×C8), 27.0 (6×C Boc), 25.4 (2×C9); HRMS (ESI.sup.+): calculated for C.sub.34H.sub.48N.sub.5O.sub.6: 622.3605, found [M+H].sup.+: 622.3591, calculated for C.sub.34H.sub.46NaN.sub.5O.sub.6: 644.3424, found [M+Na].sup.+: 644.3412.

Example 47b—Amine bis(cytisine) Derivative (154)

(275) ##STR00092##

(276) Following the general procedure A, tert-butyl(1R,5R)-10-(hydroxymethyl)-8-oxo-1,5,6,8-tetrahydro-2H-1,5-methano-pyrido[1,2-a][1,5]diazocine-3(4H)-carboxylate 153 (0.53 mmol) gave 154 (113 mg, 97%) as a colourless solid.

(277) mp: >200° C.; colourless solid; [α].sub.D.sup.23=+116 [c 0.18, DMF]; FTIR v.sub.max/cm.sup.−1 (neat): 2955, 2590, 1654, 1584, 1547, 1099, 857; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.47 (s, 2H, C3-H), 6.44 (s, 2H, C5-H), 4.07 (s, 4H, C13-H), 4.00 (d, J=15.0 Hz, 2H, C7-H), 3.86 (dd, J=15.0, 6.65 Hz, 2H, C7-H), 3.40-3.20 (m, 10H, C11-H C12-H C10-H), 2.69 (s, 2H, C8-H), 1.98 (d, J=14.5 Hz, 2H, C9-H), 1.94 (d, J=14.5 Hz, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.6 (2×CO), 148.5 (2×C4), 144.6 (2×C6), 117.5 (2×C3), 109.2 (2×C5), 49.4, 48.2 (2×C11, 2×C12), 49.1, 48.8 (2×C7, 2×C13), 31.6 (2×C10), 24.7 (2×C8), 22.5 (2×C9); HRMS (ESI.sup.+): calculated C.sub.24H.sub.32N.sub.5O.sub.2:422.2550, found [M+H].sup.+: 422.2544.

Example 48—Methylamino bis(cytisine) derivative (156)

(278) ##STR00093##

(279) To a solution of 153 (200 mg, 0.32 mmol) in an equimolar mixture of MeOH/THF (3 mL) was added formaldehyde (0.14 mL, 6 eq., 37% aq. sol.) followed by NaCNBH.sub.3 (74 mg, 3.5 eq.) and the reaction mixture was stirred for 24 h. The solution was concentrated and the crude was distributed between ammonia (20 mL, 15% aq. sol.) and DCM (20 mL), and the aqueous phase was extracted with DCM (3×20 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated. Purification by flash column chromatography [DCM/MeOH (3% MeOH)] afforded the corresponding N-Boc protected bis(cytisine) derivative (160 mg, 82%) as a colourless solid. Subsequent deprotection and conversion into the HCl salt using the general procedure B gave 156 (89 mg, 87%) as a colourless solid.

(280) mp: >200° C.; colourless solid; [α].sub.D.sup.23=−30 [c 0.3, water]; FTIR v.sub.max/cm.sup.−1 (neat): 3341, 1655, 1548, 1455; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.67 (s, 2H, C3-H, C3′-H)), 6.65 (s, 2H, C5-H, C5′-H), 4.35 (s, 4H, C13-H, C13-H), 4.18 (d, 2H, J=15.0 Hz, C7-H, C7′-H), 4.04 (dd, 2H, J=6.0, 15.0 Hz, C7-H, C7′-H), 3.60-3.40 (m, 10H, C10-H, C10′-H, C11-H, C11′-H, C12-H, C12′-H), 2.93 (s, 3H, NMe), 2.89 (s, 2H, C8-H, C8′-H), 2.23-2.06 (m, 4H, C9-H, C9′-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 161.9 (CO, CO′), 146.5 (C4, C4′), 140.6 (C6, C6′), 117.1 (C3, C3′), 107.9 (C5, C5′), 56.2 (C13, C13′), 47.0, 46.6 (C11, C11′, C12, C12′), 45.9 (C7, C7′), 38.7 (C NMe), 29.4 (C10, C10′), 22.5 (C8, C8′), 20.2 (C9, C9′); HRMS (ESI.sup.+): calculated C.sub.25H.sub.34N.sub.5O.sub.2: 436.2707, found [M+H].sup.+: 436.2692.

Example 49—(−)4-tetrazoylcytisine dihydrochloride salt (149)

(281) ##STR00094##

(282) A Schlenk flask was charged with N-Boc-4-cyano-cytisine 139 (240 mg, 0.75 mmol), zinc bromide (170 mg, 0.75 mmol) and sodium azide (58 mg, 0.90 mmol) and placed under nitrogen. Water (2.5 mL, 0.3 M) and isopropanol (0.8 mL, 1.0 M) were added and the reaction mixture was heated at 60° C. for 18 h. The solvent was removed in vacuo and the residue was dissolved in DCM (20 mL) and poured over water (20 mL). The mixture was acidified with HCl (0.1 M aq. sol.) to pH=4-5 and washed with DCM (3×20 mL). The aqueous phase was acidified to pH=1, and extracted with DCM (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and the solvent was evaporated in vacuo. The product was converted into the HCl salt using the general procedure A yielding 149 (102 mg, 53%) as a colourless solid.

(283) mp: >200° C., colourless solid; [α].sub.D.sup.23=−23 [c 0.13, DMF]; FTIR v.sub.max/cm.sup.−1 (neat): 3005, 2807, 1653, 1565; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.47 (s, 1H, C3-H), 6.44 (s, 1H, C5-H), 4.07 (s, 2H, C13-H), 4.00 (d, J=15.0 Hz, 1H, C7-H), 3.86 (dd, J=15.0, 6.65 Hz, 1H, C7-H), 3.40-3.20 (m, 5H, C10-H, C11-H, C12-H), 2.69 (s, 1H, C8-H), 1.98 (d, J=14.5 Hz, 1H, C9-H), 1.94 (d, J=14.5 Hz, 1H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.6 (CO), 155.9 (C4), 148.7 (C6), 137.3 (C13), 114.4 (C3), 106.7 (C5), 49.4, 48.2 (C11, C12), 48.8 (C7), 31.7 (C10), 24.8 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.15N.sub.6O: 259.1301, found [M+H-2HCl].sup.+: 259.1301.

Example 50—N-Boc-4-(dimethylamino)methyl-cytisine, and 4-(dimethylamino)methyl-(−)-cytisine dihydrochloride salt (151)

(284) ##STR00095##

(285) To a solution of amine 143 (320 mg, 1.0 mmol) in an equimolar mixture of THF/water (12 mL) were consecutively added formaldehyde (480 mg, 6 eq., 35% water sol.) and NaCNBH.sub.3 (219 mg, 3.5 eq.). The reaction mixture was stirred at r.t for 18 h. The reaction was quenched with 10 mL of water and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic layers were dried over MgSO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (1% MeOH)] to give the product as green oil (207 mg, 60%).

(286) Data for N-Boc4-((dimethylamino)methyl)cytisine: FTIR v.sub.max/cm.sup.−1 (neat): 2973, 2866, 1680, 1650, 1545; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.35 (s, 1H, C3-H), 6.20 (s, 1H, C5-H), 4.44-4.08 (m, 3H, C11-H, C12-H, C7-H); 3.84 (dd, 1H, J=15.0, 6.0 Hz, C7-H), 3.29 (s, 1H, C13-H), 3.20 (s, 1H, C13-H), 3.13-2.91 (m, 3H, C10-H, C11-H, C12-H), 2.41 (s, 1H, C8-H), 2.27 (s, 6H, NMe.sub.2), 2.03-1.90 (m, 2H, C9-H), 1.41-1.15 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 163.5 (CO), 154.4 (C4), 150.6/148.4 (C6 rotamers), 116.1 (C3), 106.5/105.5 (C5 rotamers), 80.3/79.7 (q Boc rotamers), 63.2 (C13), 51.6/50.5/49.3 (C11, C12 rotamers), 48.8 (C7), 45.5 (2C, NMe.sub.2), 34.8 (C10), 28.0 (3C, Boc), 27.5 (C8), 26.2 (C9) (carbonyl carbon of the Boc group has not been found); HRMS (ESI.sup.+): calculated for C.sub.19H.sub.30N.sub.3O.sub.3: 348.2282, found [M+H].sup.+:348.2281.

(287) Following the general procedure A, N-Boc-4-(Dimethylamino)methyl-cytisine (0.60 mmol) gave 151 (120 mg, 81%) as a colourless solid, which turned into a viscous oil after several days under air.

(288) Data for 4-((dimethylamino)methyl)cytisine: mp: >200° C., colourless foam; [α].sub.D.sup.26=−46 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2948, 1656, 1549, 1457; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.70 (d, J=1.5 Hz, 1H, C3-H), 6.62 (d, J=1.5 Hz, 1H, C5-H), 4.24 (s, 2H, C13-H), 4.19 (d, J=15.0 Hz, 1H, C7-H), 4.06 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.58-3.39 (m, 5H, C10-H, C11-H, C12-H), 2.92 (s, 6H, NMe.sub.2), 2.88 (s, 1H, C8-H), 2.15 (m, 2H, C9-H); .sup.13C NMR (MHz, D.sub.2O, δ.sub.C): 164.5 (CO), 148.6 (C6), 143.2 (C4), 118.9 (C3), 109.7 (C5), 59.1 (C13), 49.3, 48.7 (C11, C12), 48.1 (C7), 42.7 (2C, NMe.sub.2), 31.5 (C10), 24.7 (C8), 22.4 (C9); HRMS (ESI.sup.+): calculated C.sub.14H.sub.22N.sub.3O: 248.1757, found [M+H—HCl].sup.+: 248.1755.

Example 51—(−)4-((trimethylammonium)methyl)cytisine iodide salt (150)

(289) ##STR00096##

(290) To a solution of amine 143 (220 mg, 0.63 mmol) in EtOH (6.3 mL) was added iodomethane (0.1 mL, 1.3 eq.) and the reaction was stirred for 18 h at 60° C. The solution was concentrated. Deprotection and conversion into the HCl salt using the general procedure A yielding 150 (80 mg, 42%) as a off-green amorphous solid.

(291) Mp: ≥200° C.; [α].sub.D.sup.23=−65 [c 1.3, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 1656, 1551, 1479; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.77 (s, 1H, C3-H), 6.70 (s, 1H, C5-H), 4.42 (s, 2H, C13-H), 4.20 (d, J=15.0 Hz, 1H, C7-H), 4.09 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.60-3.41 (m, 5H, C10-H C11-H C12-H), 3.19 (s, 9H, NMe.sub.3), 2.89 (s, 1H, C8-H), 2.20 (d, J=14.0 Hz, 1H, C9-H), 2.12 (d, J=14.0 Hz, 1H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 164.3 (CO), 148.4 (C4), 140.8 (C6), 121.9 (C3), 111.7 (C5), 67.5 (C13), 53.2 (3C, NMe.sub.3), 49.4, 48.2 (C11, C12), 48.8 (C7), 31.6 (C10), 24.7 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated C.sub.15H.sub.24N.sub.3O: 262.1913, found [M+H.sup.+—HCl—Cl.sup.−]: 262.1924.

Example 52—(−)4-(N-acetyl)aminomethyl) cytisine (148)

(292) ##STR00097##

(293) Amine 143 (310 mg, 1.0 mmol) was dissolved in isopropenyl acetate (0.33 mL, 3 eq.) and stirred at r.t. for 24 h. Then, the reaction was concentrated. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (3% MeOH)] to give the product (330 mg, 92%) as a colourless solid. Deprotection and conversion using the general procedure A gave 148 (237 mg, 80%) as a colourless foam.

(294) mp: >200° C., colourless foam; [α].sub.D.sup.23=−20 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 2197 (w), 1678, 1640, 1571, 1468; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.54-6.44 (m, 2H, C3-H, C5-H), 4.29 (s, 2H, C13-H), 4.17 (d, J=15.0 Hz, 1H, C7-H), 4.04 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.55-3.38 (m, 5H, C10-H, C11-H, C12-H), 2.83 (s, 1H, C8-H), 2.18-2.05 (m, 5H, C9-H C16-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 174.6 (C14), 164.7 (CO), 153.3 (C4), 146.9 (C6), 112.3 (C3), 108.7 (C5), 49.5, 48.2 (C11, C12), 48.6 (C7), 41.7 (C13), 31.5 (C10), 24.8 (C8), 22.60 (C9), 21.7 (C15); HRMS (ESI.sup.+): calculated C.sub.14H.sub.20N.sub.3O: 262.1550, found [M+H—HCl].sup.+: 262.1543.

Example 53—N-Boc 4-(4-((benzyloxy)carbonyl)piperazin-1-yl)cytisine (89)

(295) ##STR00098##

(296) A solution of bromide 61 (180 mg, 0.5 mmol), Cu.sub.2O (8 mg, 0.1 eq.) and 1-Z-piperazine (0.5 mL, 2.5 mmol) in water (1.0 mL) was stirred in a seal tube at 100° C. for 18 h. The reaction was cooled and the residue was extracted with EtOAc (3×25 mL). The combined organic layers were dried on MgSO.sub.4, filtered and concentrated in vacuo. The crude reaction mixture was purified by flash column chromatography on silica gel [DCM/MeOH (2% MeOH)] to give 89 as colourless solid (220 mg, 89%), which was used in the next step without further purification.

(297) .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 7.37-7.30 (m, 5H, Ar), 5.74 (d, J=2.5 Hz, 1H, C3-H), 5.64 (s, 1H, C5-H), 5.16 (s, 2H, CH.sub.2-Ph), 4.39-4.06 (m, 3H, C7-H, C11-H, C12-H), 3.77 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.60 (m, 4H, C13-H), 3.27 (m, 4H, C14-H), 3.01 (m, 2H, C11-H C12-H), 2.87 (s, 1H, C10-H), 2.35 (s, 1H, C8-H), 1.97 (d, J=12.5 Hz, 1H, C9-H), 1.89 (d, J=12.5 Hz, 1H, C9-H), 1.40-1.18 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 164.3 (CO), 156.4 (CO), 155.1 (CO), 154.6 (C4), 148.3 (C6), 136.4 (Ar), 128.5 (2C, Ar), 128.1 (Ar), 127.9 (2C, Ar), 96.4 (C3), 95.0 (C5), 80.1 (q Boc), 67.7 (CH.sub.2-Ph), 50.6, 50.5 (C11, C12), 47.9 (C7), 46.1 (2C, C13), 43.1 (2C, C14), 35.4 (C10), 28.1 (3C, Boc), 27.7 (C8), 26.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.28H.sub.37N.sub.4O.sub.5: 509.2758, found [M+H].sup.+: 509.2733.

Example 54—N-Boc 4-(piperazin-1-yl) cytisine

(298) ##STR00099##

(299) A solution of 89 (160 mg, 0.32 mmol) in methanol (5 mL) was placed under nitrogen and palladium on activated charcoal 10 wt % (5 mg, 0.1 eq.) was added. The vessel was placed under vacuum and backfilled with hydrogen for three times and stirred for 18 h. The reaction mixture was filtered through Celite® and the solvent was concentrated, giving the piperazinyl derivative (85 mg, 71%) as a colourless solid, which was used in the next step without further purification.

(300) .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 5.85 (s, 1H, C3-H), 5.72 (s, 1H, C5-H), 5.49 (br, 1H, NH), 4.33-4.01 (m, 3H, C7-H, C11-H, C12-H), 3.74 (dd, J=15.0, 6.0 Hz, 1H, C7-H), 3.55 (s, 4H, C13-H), 3.19 (s, 4H, C14-H), 3.07-2.94 (m, 2H, C11-H, C12-H), 2.92 (s, 1H, C10-H), 2.36 (s, 1H, C8-H), 1.96 (d, J=13.5 Hz, 1H, C9-H), 1.89 (d, J=13.5 Hz, 1H, C9-H); 1.38-1.19 (s, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 164.6 (CO), 156.4 (CO), 154.5 (C4), 148.8 (C6), 96.9 (C3), 95.0 (C5), 80.0 (q Boc), 50.6, 50.5 (C11, C12), 48.2 (C7), 44.7 (2C, C13), 43.6 (2C, C14), 35.2 (C10), 28.1 (3C, Boc), 27.5 (C8), 26.4 (C9); HRMS (ESI.sup.+): calculated C.sub.20H.sub.31N.sub.4O.sub.3: 375.2391, found [M+H].sup.+: 375.2383.

Example 55—(+)4-(N-piperazinyl)cytisine trihydrochloride salt (90)

(301) ##STR00100##

(302) A solution of N-Boc 4-N—(N′-Cbz)-piperazine-cytisine (323 mg, 0.64 mmol) in MeOH (6.4 mL) was placed under nitrogen and Pd/C (10 wt %) (6.5 mg, 0.1 eq) was added. The vessel was placed under vacuum and backfilled with hydrogen for three times and stirred for 24 h. The mixture was filtered through Celite® and concentrated in vacuo. Deprotection and conversion into its HCl salt using the general procedure A gave 90 (237 mg, 96%) as a colourless solid.

(303) mp: >200° C., colourless powder; [α].sub.D.sup.25=+52 [c 1.0, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3374, 2924, 2712, 2585, 2451, 1638, 1538; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.55 (s, 1H, C3-H), 4.10 (d, J=15.0 Hz, 1H, C7-H.sub.a), 3.98 (dd, J=6.5, 15.0 Hz, 1H, C7-H.sub.b), 3.69-3.66 (m, 4H, C14-H), 3.47-3.26 (m, 9H, C10-H, C11-H, C12-H, C13-H), 2.70 (s, 1H, C8-H), 2.07-1.96 (m, 2H, C9-H), C5-H not detected due to deuterium exchange; .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 162.1 (CO), 157.2 (C4), 148.1 (C6), 102.4 (C3), 92.2-91.7 (m, C5), 49.2 (C11 or C12), 48.8 (C7), 48.1 (C11 or C12), 42.7 (2C, C13), 42.5 (2C, C14), 31.7 (C10), 24.5 (C8), 22.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.15H.sub.23N.sub.4O: 275.1866, found [M+H-3HCl].sup.+: 275.1868.

Example 56a—N-Boc 3-(trifluoromethyl)-4-bromocytisine 161

(304) ##STR00101##

(305) A solution of N-Boc 4-bromo-cytisine 61 (370 mg, 1.0 mmol) in a mixture of DMSO (3.8 mL) H.sub.2O (1.6 mL) was cooled to 0° C. and sodium trifluoromethylsulfonate (470 mg, 3.0 mmol) was added. Tert-butyl hydroperoxide (0.7 mL, 70% aq.sol.) was added dropwise during 5 min. and the solution was allowed to warm to r.t. and stirred for 24 h. The solvent was removed in vacuo. The crude was distributed between ammonia (15 mL, 15% aq. sol.) and DCM (15 mL), and the aqueous phase was extracted with DCM (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The crude was purified by flash column chromatography on silica gel [n-Hexane/EtOAc (1:1)] to give 161 (130 mg, 30%) as colourless solid, together with 3% of N-Boc-5-CF.sub.3-4-Bromo-cytisine. [1H NMR: 98% (C3-substituted), 2% (C5-substituted; 87% conversion)].

(306) FTIR v.sub.max/cm.sup.−1 (neat): 2972, 2923, 2865, 1677, 1645, 1543; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.41 (s, 1H, C5-H), 4.45-4.10 (m, 3H, C7-H, C11-H, C12-H), 3.88-3.76 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.23-2.91 (m, 3H, C11-H, C12-H, C10-H), 2.48 (s, 1H, C8-H), 1.99 (s, 2H, C9-H), 1.44-1.18 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 158.7 (CO), 154.5/154.0 (CO, rotamers), 152.2/151.7 (C6), 135.0/134.7 (C4), 122.6 (q, J=276 Hz, CF.sub.3), 116.2 (q, J=30 Hz, C3), 121.3/110.5 (C5, rotamers), 80.9/80.3 (q Boc, rotamers), 51.2/50.4/49.8/49.1 (C11, C12, rotamers), 49.4 (C7, rotamers), 34.7 (C10), 28.0 (3C, Boc), 27.2 (C8), 25.5 (C9); HRMS (ESI.sup.+): calculated for C.sub.17H.sub.21BrF.sub.3N.sub.2O.sub.3: 437.0682, found [M+H].sup.+: 437.0679.

Example 56b—(−)3-(Trifluoromethyl)-4-bromocytisine hydrochloride salt (162)

(307) ##STR00102##

(308) Following the general procedure A, bromide 161 (0.25 mmol) gave 162 (0.45 mg, 48%).

(309) mp: >200° C., colourless powder; [α].sub.D.sup.23=−19 [c 0.20, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 1651, 1543, 1130, 1076; .sup.1H NMR (400 MHz, D.sub.2O, δ.sub.H): 6.83 (s, 1H, C5-H), 4.04 (d, J=15.5 Hz, 1H, C7-H), 3.89 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.46-3.28 (m, 5H, C10-H, C11-H, C12-H), 2.76 (s, 1H, C8-H), 2.06 (d, J=13.5 Hz, 1H, C9-H), 2.00 (d, J=13.5 Hz, 1H, C9-H); .sup.13C NMR (100 MHz, D.sub.2O, δ.sub.C): 160.7 (CO), 150.3 (C6), 136.5 (C4), 122.4 (q, J=275 Hz, CF.sub.3), 116.2 (q, J=30 Hz, C3-H), 114.3 (C5-H), 48.9, 48.0 (C11, C12), 48.8 (C7), 31.4 (C10), 24.5 (C8), 22.1 (C9); HRMS (ESI.sup.+): calculated for C.sub.12H.sub.13BrF.sub.3N.sub.2O: 337.0158, found [M+H].sup.+: 337.0162.

Example 57a—N-Boc 3-bromo-4-iodocytisine (159)

(310) ##STR00103##

(311) N-Boc-4-iodo-cytisine 65 (120 mg, 0.286 mmol) was dissolved in THF (6 mL, 0.05 M) and N-bromosuccinimide (51 mg, 0.286 mmol) was added. The reaction mixture was stirred at r.t. for 24 h. The reaction was diluted with water (15 mL), and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The crude was purified by flash column chromatography on silica gel [n-Hexane/EtOAc (1:1)] to give 159 (91 mg, 65%), contaminated with N-Boc-5-bromo-4-iodo-cytisine (in a ratio 22:3).

(312) FTIR v.sub.max/cm.sup.−1 (neat): 2925, 2865, 1669, 1634, 1569; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 6.58 (s, 1H, C5-H), 4.43-4.06 (m, 3H, C7-H, C11-H, C12-H), 3.78 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.16-2.86 (m, 3H, C10-H, C11-H, C12-H), 2.42 (s, 1H, C8-H), 1.96 (m, 2H, C9-H), 1.40-1.15 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 157.7 (CO), 156.5 (CO), 154.6/154.1 (C6, rotamers), 147.7/147.2 (C4, rotamers), 121.4 (C3), 115.5/114.9 (C5, rotamers), 80.6/80.1 (q Boc, rotamers), 51.8/51.5/50.0/49.4 (C11, C12, rotamers), 50.4 (C7, rotamers), 34.3 (C10), 28.1 (3C, Boc), 27.4 (C8), 25.9 (C9), HRMS (ESI.sup.+): calculated for C.sub.16H.sub.21BrIN.sub.2O.sub.3: 494.9774, found [M+H].sup.+: 494.9761.

Example 57b—(+)3-Bromo-4-iodocytisine hydrochloride salt (160)

(313) ##STR00104##

(314) Following the general procedure A, iodide 159 (0.16 mmol) gave 160 (57 mg, 81%); contaminated with 5-bromo-4-iodo-cytisine (ratio 22:3).

(315) [α].sub.D.sup.23=+7 [c 0.3, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2985, 1606, 1566, 1096; .sup.1H NMR (500 MHz, DMSO, δ.sub.H): 6.83 (s, 1H, C5-H), 3.92 (d, J=15.5 Hz, 1H, C7-H), 3.79 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.33-3.12 (m, 5H, C11-H, C12-H, C10-H), 2.62 (s, 1H, C8-H), 1.99 (d, J=13.5 Hz, 1H, C9-H), 1.87 (d, J=13.5 Hz, 1H, C9-H); .sup.13C NMR (125 MHz, DMSO, δ.sub.C): 157.7 (CO), 147.7 (C6), 121.0 (C4), 116.4 (C3), 115.6 (C5), 49.8 (C7), 48.8, 48.0 (C11, C12), 30.9 (C10), 14.9 (C8), 22.9 (C9); HRMS (ESI.sup.+): calculated for C.sub.11H.sub.13BrIN.sub.2O: 394.9250, found [M+H—HCl].sup.+: 394.9249.

Example 58a—N-Boc 3-Bromo-4-methylaminocytisine (157)

(316) ##STR00105##

(317) To a solution of N-methyl amine 83 (96 mg, 0.30 mmol) in THF (6.0 mL) was added N-bromosuccinimide (54 mg, 0.30 mmol) and the reaction was stirred at r.t. for 24 h. The reaction was diluted with water (15 mL) and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. The crude was purified by flash column chromatography on silica gel [DCM/MeOH (2% MeOH)] to give 157 (N-Boc-3-bromo-4-methylamino-cytisine) (84 mg, 70%), and N-Boc-5-bromo-4-methylamino (27 mg, 22%), which was used in the next step without further purification.

(318) Data for 157: FTIR v.sub.max/cm.sup.−1 (neat): 3290, 2946, 2761, 2623, 1633, 1493, 1206, 1100, 1025, 567, 521; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 5.68 (s, 1H, C5-H), 4.84 (s, 1H, NH), 4.36-4.05 (m, 3H, C11-H, C12-H, C7-H), 3.79 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.13-2.85 (m, 6H, C11-H, C12-H, C10-H, NHMe), 2.33 (s, 1H, C8-H), 1.91 (m, 2H, C9-H), 1.36-1.13 (m, 9H, Boc); .sup.13C NMR (125 MHz, CDCl.sub.3, δ.sub.C): 159.2 (CO), 154.7, 154.2 (C6, rotamers), 152.4 (CO), 148.0, 147.7 (C4, rotamers), 93.0, 92.5 (C5-H), 90.4 (C3), 80.3, 79.7 (q Boc, rotamers), 51.6, 50.6, 50.2, 49.3 (C11, C12), 49.1 (C7), 35.0 (C10), 29.8 (C8), 28.0, 27.7 (Boc, rotamers), 26.2 (C9).

Example 58b—(+)3-Bromo-4-N-methylaminocytisine hydrochloride salt (158)

(319) ##STR00106##

(320) Following the general procedure A, N-Methyl amine 157 (0.21 mmol) gave 158 (45 mg, 73%) as a colourless solid, contaminated with 9% of 5-Bromo-4-methylamino-cytisine.

(321) [α].sub.D.sup.23=+38 [c 0.5, MeOH]; FTIR v.sub.max/cm.sup.−1 (neat): 3291, 2949, 2761, 2624, 1634, 1583; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.14 (s, 1H, C5-H), 4.13 (d, J=15.5 Hz, 1H, C7-H), 3.88 (dd, J=6.5, 15.5 Hz, 1H, C7-H), 3.52-3.32 (m, 5H, C11-H, C12-H, C10-H), 2.84 (s, 3H, NHMe), 2.70 (s, 1H, C8-H), 2.04 (m, 2H, C9-H); .sup.13C NMR (125 MHz, D.sub.2O, δ.sub.C): 160.5 (CO), 154.3 (C6), 145.6 (C4), 97.0 (C3), 89.6 (C5), 49.3, 48.5 (C11, C12), 48.9 (C7), 31.6 (C10), 28.9 (NHMe), 24.9 (C8), 22.9 (C9); HRMS(ESI.sup.+): calculated for C.sub.12H.sub.17BrN.sub.3O: 298.0549, found [M+H].sup.+: 298.0549.

Example 59—Iridium-catalyzed C—H borylation of (−)-cytisine

Synthesis of 4-Bpincytisine

(322) A Schlenk tube was charged with (−)-cytisine (190 mg, 1.0 mmol), [Ir(COD)(OMe)]2 (6.6 mg, 0.01 eq), 4,4′-2,2′-di-tert-butylbispyridine (5.4 mg, 0.02 eq) and bis(pinacolato)diboron (380 mg, 1.50 eq). After purging with nitrogen, THF (1.4 mL) was added and the reaction mixture was heated at reflux for 24 h. After this time, the volatile materials were removed under reduced pressure and 4-Bpincytisine was partially characterized without further purification and obtained as a brown foam.

(323) 1H NMR (500 MHz, CDCl.sub.3): δ=6.88 (d, 1H, J=1.0 Hz), 6.27 (s, 1H), 4.11 (d, 1H, J=15.5 Hz), 3.86 (dd, 1H, J=6.5, 15.5 Hz), 3.15-2.78 (m, 5H), 3.21 (s, 1H), 1.94-1.91 (m, 2H), 1.23 (s, 12H).

(324) 13C NMR (125 MHz, CDCl.sub.3): δ=163.1, 149.2, 124.1, 108.8, 84.4, 82.7, 53.3, 52.3, 49.6, 35.1, 27.5, 25.5, 14.5.

(325) To confirm the identity of 4-Bpincytisine, that compound was further converted to 4-bromocytisine by treatment with an aqueous solution of CuBr.sub.2 in MeOH. The spectroscopic properties of 4-bromocytisine were consistent with the data available in literature.

Example 60—Iridium-catalyzed C—H borylation of (−)-cytisine

Synthesis of 4-Bpincytisine

(326) The process of Example 59 was carried out, using the same apparatus and solvents, catalysts and ligands in the same molar amounts as outlined above, except that Me4phen was used as a ligand and the borylating agent B.sub.2Pin.sub.2 was present at 3.00 eq. The process resulted in 100% conversion of cytisine to 4-Bpincytisine.

Example 61—Iridium-catalyzed C—H borylation of (−)-cytisine

Synthesis of 4-Bpincytisine

(327) The process of Example 59 was carried out, using the same apparatus and solvents, catalysts and ligands in the same molar amounts as outlined above, except that neocuproine was used as a ligand. The process resulted in 100% conversion of cytisine to 4-Bpincytisine.

Example 62—Iridium-Catalyzed C—H Borylation of N-Boc Cytisine (56)

Synthesis of N-Boc 4-Bpincytisine (58)

(328) A Schlenk tube was charged with N-Boc cytisine (56) (290 mg, 1.0 mmol), [Ir(COD)(OMe)]2 (6.6 mg, 0.01 eq), 4,4′-2,2′-di-tert-butylbispyridine (5.4 mg, 0.02 eq) and bis(pinacolato)diboron (178 mg, 0.70 eq). After purging with nitrogen, THF (1.4 mL) was added and the reaction mixture was heated at reflux for 18 h. After this time, 1H NMR showed essentially 100% conversion, the volatile materials were removed under reduced pressure.

(329) The crude product N-Boc 4-Bpincytisine (58) was shown to be essentially pure by 1H NMR and although further purification is possible, this is unnecessary prior to using N-Boc 4-Bpincytisine (58) as a reactant.

(330) Further purification of crude N-Boc 4-Bpincytisine (58) was achieved using chromatography (DCM-MeOH, 95:5) to give pure N-Boc 4-Bpincytisine (58) (180 mg, 43%) as a pale yellow foam;

(331) Rf=0.23 (DCM-MeOH, 95:5).

(332) IR (neat): 3433, 2977, 1688, 1657, 1563, 1423 cm-1.

(333) 1H NMR (400 MHz, CDCl.sub.3): δ=6.85 (s, 1H), 6.31 (s, 1H), 4.34-4.10 (m, 3H), 3.80 (dd, 1H, J=6.5, 15.5 Hz), 3.07-2.91 (m, 3H), 2.41 (s, 1H), 1.95-1.88 (m, 2H), 1.41-1.09 (m, 21H).

(334) 13C NMR (100 MHz, CDCl.sub.3): δ=162.9, 154.6/154.3 (rotamers), 147.9/147.5 (rotamers), 124.4, 109.3/108.8 (rotamers), 84.4, 82.6/80.3, 79.7/75.0 (2C, rotamers), 51.7/50.6/50.3/49.2 (2C, rotamers), 48.9, 34.7, 28.0 (4C), 27.5, 26.1, 24.8/24.6 (3C, rotamers); C-Bpin was not observed.

(335) 11B NMR (96.4 MHz, CDCl.sub.3): δ=28.94 (br s).

(336) HRMS-ESI: m/z [M+H]+ calcd for C22H33BN2NaO5: 439.2379; found: 439.2373.

Example 63—Iridium-Catalyzed C—H Borylation of N-Boc Cytisine (56)

Synthesis of N-Boc 4-Bpincytisine (58)

(337) The process of Example 62 was carried out, using the same apparatus and solvents, catalysts and ligands in the same molar amounts as outlined above, except that N-methyl cytisine was used as a starting material of Formula IIa. The process resulted in 98% conversion of cytisine to 4-Bpincytisine.

Example 64—Iridium-Catalyzed C—H Borylation of N-Boc Cytisine (56)

Synthesis of N-Boc 4-Bpincytisine (58)

(338) The process of Example 62 was carried out, using the same apparatus and solvents, catalysts and ligands in the same molar amounts as outlined above, except that N-Cbz cytisine was used as a starting material of Formula IIa. The process resulted in 88% conversion of cytisine to 4-Bpincytisine.

Example 65—N-Boc 4-p-tolylcytisine (72)

(339) N-Boc 4-Bpincytisine 58 was made following the general procedure discussed above on a 0.5 mmol scale. To crude N-Boc 4-Bpincytisine was added potassium carbonate (124 mg, 0.90 mmol), tetrakis (triphenylphosphine) palladium(0) (28 mg, 0.05 eq) and 4-bromotoluene (0.25 mL, 1.0 mmol) and a mixture of DME/water (5:1) (5 mL, 0.1 M) was added. The mixture was heated at 80° C. for 24 h, then cooled to room temperature and diluted with water (15 mL). The aqueous phase was extracted with DCM (3×15 mL) and the combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification by flash column chromatography [DCM/MeOH (1.5% MeOH)] afforded N-Boc 4-(p tolyl)cytisine (104 mg, 55%) as a colourless solid.

Example 66—N-Boc 4-methylcytisine (109)

(340) N-Boc 4-Bpincytisine 58 was made following the general procedure discussed above for the borylation of cytisine on a 0.5 mmol scale.

(341) Using a modification of a related procedure, to crude N-Boc 4-Bpincytisine 58 were added Pd.sub.2dba.sub.3 (11 mg, 0.025 eq), tri(p tolyl)phosphine (7.6 mg, 0.05 eq), potassium carbonate (138 mg, 2.0 eq), iodomethane (0.03 mL, 1.0 eq) and the vessel was placed under vacuum and backfilled with nitrogen three times. A mixture of DMF/water (9:1.5 mL) was added and the reaction mixture was stirred at 60° C. for 18 h. The mixture was cooled to r.t. and the solvent removed in vacuo. The residue was partitioned between EtOAc (15 mL) and water (15 mL) and the aqueous phase was extracted with EtOAc (3×15 mL). The combined organic phases were dried over MgSO.sub.4, filtered, concentrated and purified by flash column chromatography on silica gel [DCM/MeOH (3% MeOH)] to give N-Boc 4-methylcytisine (98 mg, 64%) as a pale yellow solid.

Example 67a—N-Boc (3-bromo-4-hydroxy)cytisine

(342) ##STR00107##

(343) A solution of N-Boc 4-aminocytisine (512 mg, 1.67 mmol) in THF (32 mL) was cooled to 0° C., N-bromosuccinimide (312 mg, 1.76 mmol) was added, and the reaction mixture was stirred at 0° C. for 18 hours. Water (25 mL) was added and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [EtOAc/MeOH (1% MeOH)] afforded N-Boc (3-bromo-4-hydroxy)cytisine (350 mg, 55%) as a colourless solid.

(344) R.sub.f: 0.37 [DCM/MeOH (5% MeOH)]; FTIR v.sub.max/cm.sup.−1 (neat): 2864, 1698, 1581, 1408, 1245, 1129; .sup.1H NMR (500 MHz, DMSO, δ.sub.H): 11.00 (s, 1H), 5.94 (s, 1H), 4.18-3.81 (m, 3H), 3.58 (dd, J=15.0, 6.5 Hz, 1H), 3.14-2.85 (m, 3H), 2.30 (s, 1H), 1.85 (s, 2H), 1.29-1.02 (m, 9H); .sup.13C NMR (500 MHz, DMSO, δ.sub.C): 162.6, 160.4, 154.1, 149.0, 98.0, 93.2, 79.1, 51.7, 50.5, 49.6, 34.3, 28.0, 27.4, 25.7; HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22.sup.79BrN.sub.2O.sub.4: 385.0757, found [M+H].sup.+: 385.0764.

Example 67b—(−)-(3-bromo-4-hydroxy)cytisine hydrochloride salt (BS70)

(345) ##STR00108##

(346) Following the general procedure A, N-Boc (3-bromo-4-hydroxy)cytisine (0.83 mmol) gave BS70 (236 mg, quantitative) as a colourless solid.

(347) mp: >200° C.; [α].sub.D.sup.24=−0.12 [c 1.0, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2573, 1646, 1550, 1408, 1310, 1097, 854; .sup.1H NMR (500 MHz, D.sub.2O, δ.sub.H): 6.34 (s, 1H), 4.26 (d, J=15.5 Hz, 1H), 4.00 (dd, J=15.5, 7.0 Hz, 1H), 3.60 (d, J=13.5 Hz, 1H), 3.50-3.40 (m, 4H), 2.82 (s, 1H), 2.13 (m, 2H); .sup.13C NMR (500 MHz, D.sub.2O, δ.sub.C): 163.3, 162.3, 146.4, 101.5, 94.8, 49.3, 49.2, 48.3, 31.4, 24.8, 22.7; HRMS (ESI.sup.+): calculated for C.sub.11H.sub.14.sup.79BrN.sub.2O.sub.2: 285.0160, found [M+H].sup.+: 285.0230.

Example 68a—N-Boc (3-bromo-4-amino)cytisine

(348) ##STR00109##

(349) A solution of 4-aminocytisine (250 mg, 0.82 mmol) in THF (16 mL) was cooled to 0° C., N-bromosuccinimide (153 mg, 0.86 mmol) was added, and the reaction mixture was stirred at 0° C. for 18 hours. Water (25 mL) was added and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flash column chromatography [EtOAc] afforded N-Boc (3-bromo-4-amino)cytisine (95 mg, 30%) as a colourless solid.

(350) R.sub.f: 0.43 [DCM/MeOH (6% MeOH)]; mp: ≥200° C. (toluene); FTIR v.sub.max/cm.sup.−1 (neat): 3441, 3178, 2917, 1682, 1633, 1591, 1427, 1124, 820, 751; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 5.67 (s, 1H), 4.59 (s, 2H), 4.43-4.00 (m, 3H), 3.82 (dd, J=15.5, 6.5 Hz, 1H), 3.13-2.87 (m, 3H), 2.36 (s, 1H), 1.95 (d, J=12.5 Hz, 1H), 1.91 (d, J=12.5 Hz, 1H), 1.39-1.18 (m, 9H); .sup.13C NMR (500 MHz, CDCl.sub.3, δ.sub.C): 159.8, 154.4, 151.5, 146.9, 96.1, 91.4, 80.3, 51.5, 50.4, 49.3, 34.7, 28.0, 27.4, 26.3; HRMS (ESI.sup.+): calculated for C.sub.16H.sub.22.sup.81BrN.sub.3NaO.sub.3: 408.0737, found [M+Na].sup.+: 408.0713.

Example 68b—(+)-(3-bromo-4-amino)cytisine hydrochloride salt (BS71)

(351) ##STR00110##

(352) Following the general procedure A, N-Boc (3-bromo-4-amino)cytisine gave BS71 (62 mg, 64%) as a colourless solid.

(353) mp: ≥200° C. (toluene); [α].sub.D.sup.24=+0.08 [c 1.0, water]; FTIR v.sub.max/cm.sup.−1 (neat): 3313, 3132, 2934, 2756, 1641, 1532, 1454, 1163; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 6.15 (s, 1H), 4.37 (d, J=15.5 Hz, 1H), 3.92 (dd, J=15.5, 6.5 Hz, 1H), 3.54 (d, J=13.0 Hz, 1H), 3.49-3.36 (m, 3H), 3.31 (s, 1H), 2.70 (s, 1H), 2.15 (d, J=13.5 Hz, 1H), 2.07 (d, J=13.5 Hz, 1H); .sup.13C NMR (500 MHz, MeOD, δ.sub.C): 159.9, 154.7, 144.9, 100.2, 89.3, 49.2, 48.9, 48.3, 31.6, 25.4, 23.2; HRMS (ESI.sup.+): calculated for C.sub.11H.sub.15.sup.79BrN.sub.3O: 284.0393, found [M+H].sup.+: 284.0390.

Example 69a—N-Boc (3-bromo-4-ethyl)cytisine

(354) ##STR00111##

(355) A solution of N-Boc 4-ethyl-cytisine (341 mg, 1.07 mmol) in THF (20 mL) was cooled to 0° C., N-bromosuccinimide (190 mg, 1.07 mmol) was added, and the reaction mixture was stirred at 0° C. for 18 hours. Water (25 mL) was added and the aqueous phase was extracted with EtOAc (3×25 mL). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated. Purification of the crude reaction mixture by flask column chromatography [DCM/MeOH (2% MeOH)] afforded N-Boc (3-bromo-4-ethyl)cytisine (296 mg, 70%) as a colourless solid.

(356) R.sub.f: 0.22 [DCM/MeOH (2% MeOH)]; .sup.1H NMR (500 MHz, CDCl.sub.3, δ.sub.H): 5.99 (s, 1H), 4.45-4.02 (m, 3H), 3.86 (dd, J=15.5, 6.5 Hz, 1H), 3.16-2.86 (m, 3H), 2.66 (m, 2H), 2.40 (s, 1H), 2.00-1.88 (m, 2H), 1.44-1.03 (m, 12H); .sup.13C NMR (500 MHz, CDCl.sub.3, δ.sub.C): 159.5, 154.5, 146.8, 112.9, 106.3, 80.3, 51.5, 50.4, 50.0, 29.8, 29.6, 28.0, 27.4, 26.2, 12.7, (C9 has not been found); HRMS (ESI.sup.+): calculated for C.sub.18H.sub.26.sup.79BrN.sub.2O.sub.3: 397.1121, found [M+H].sup.+: 397.1121.

Example 69b—(−)-(3-bromo-4-ethyl)cytisine (BS74)

(357) ##STR00112##

(358) Following the general procedure A, N-Boc (3-bromo-4-ethyl)cytisine (296 mg, 0.75 mmol) gave BS74 (80 mg, 37%) as a colourless solid.

(359) mp: ≥200° C.; [α].sub.D.sup.24=−0.21 [c 1.0, water]; FTIR v.sub.max/cm.sup.−1 (neat): 2935, 2544, 1635, 1572, 1450, 1101, 705; .sup.1H NMR (500 MHz, MeOD, δ.sub.H): 6.50 (s, 1H), 4.45 (d, J=15.5 Hz, 1H), 4.02 (dd, J=15.5, 6.5 Hz, 1H), 3.63 (d, J=13.5 Hz, 1H), 3.54-3.42 (m, 4H), 2.81 (s, 1H), 2.72 (m, 2H), 2.22 (d, J=13.5 Hz, 1H), 2.12 (d, J=13.5 Hz, 1H), 1.25 (t, J10=7.0 Hz, 3H); .sup.13C NMR (500 MHz, MeOD, δ.sub.C): 159.9, 156.0, 144.9, 112.9, 108.8, 49.6, 49.3, 48.4, 31.6, 29.4, 25.4, 22.9, 11.5; HRMS (ESI.sup.+): calculated for C.sub.13H.sub.18.sup.79BrN.sub.2O: 297.0597, found [M+H].sup.+: 297.0591.

Example 70 Binding to Nicotinic Receptor Subtypes

(360) The binding of a group of compounds mentioned above were tested for their affinity at different nAChR subtypes, specifically the α4β2, the α3β4 and α7. The protocol for these tests is set out below, and the results are provided at Table 1 below.

(361) Binding to Heterologously Expressed_α4β2 and α3β4 Human Subtypes

(362) HEK 293 cells were grown in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% L-Glutamine, 100 units/ml penicillin G, and 100 μg/streptomycin in a humidified atmosphere containing 10% CO.sub.2. The cDNAs encoding α3 and β4 or α4 and β2 (were transfected into the HEK 293 cells at 30% confluency). The cell transfections were carried out in 100 mm Petri dishes using 30 μL of JetPEI™ (Polypus, France) (1 mg/ml, pH 7.2) and 3 μg of each cDNA. After 24 h transfection, the cells were collected, washed with PBS by centrifugation, and used for binding analysis.

(363) [.sup.3H]-epibatidine saturation binding experiments to HEK transfected α3β4 or α4β2 receptors were performed by means of overnight incubation at 4° C. at concentrations ranging from 0.005 to 1 nM in a buffer containing 50 mM Tris-HCl, pH 7, 150 mM NaCl, 5 mM KCl, 1 mM MgCl.sub.2, 2.5 mM CaCl.sub.2 and 2 mg/ml BSA, in the presence (aspecific binding) or absence (total binding) of 100 nM cold epibatidine. Specific ligand binding was defined as total binding minus the binding in the presence of 100 nM cold epibatidine.

(364) The inhibition of [.sup.3H]-epibatidine binding induced by the compounds or nicotinic ligands was measured by incubating increasing concentrations (10 pM-10 mM) of the test compounds for 30 min at room temperature (r.t.), followed by overnight incubation at 4° C. with a final concentration of 0.25 nM [.sup.3H]-epibatidine (in the case of the α4β2* subtype) or 0.5 nM (in the case of the α3β4 subtype). After incubation, the membranes of HEK cells transfected with α4β2* or α3β4 subtypes were washed by filtration on GFC filters with ice-cold PBS. The GFC filters were pre-soaked in polyethylenimine and filtered through an harvester apparatus. [.sup.3H]-epibatidine binding was determined by means of liquid scintillation counting in a beta counter.

(365) Binding to Heterologously Expressed_α7 Subtype

(366) The human α7 cDNA was transfected into SH-SY5Y human neuroblastoma cells. The cell transfections were carried out in 100 mm Petri dishes using 30 μL of JetPEI™ (Polypus, France) (1 mg/ml, pH 7.2) and 6 μg of α7 cDNA. After 24 h transfection, the cells were collected, washed with PBS by centrifugation, and used for binding analysis.

(367) The [.sup.125I]-α-Bungarotoxin (purchased from Perkin Elmer, Boston Mass.) saturation binding was performed by incubating SH-SY5Y membranes overnight with 0.1-10 nM concentrations of [.sup.125I]-α-bungarotoxin at r.t. Non-specific binding was determined in parallel by means of incubation in the presence of 1 μM unlabelled α-bungarotoxin. After incubation, the samples were filtered as described above and the bound radioactivity directly counted in a γ counter. The inhibition of [.sup.125I]-α-Bungarotoxin binding by the test compounds was measured by preincubating SH-SY5Y membranes with increasing concentrations (10 M-1 mM) of the drug to be tested for 30 min at r.t., followed by overnight incubation with a final concentration of 2-3 nM [.sup.125I]-α-bungarotoxin at room temperature.

(368) After overnight incubation, the membranes of SH-SY5Y cells transfected with α7 were washed by filtration on GFC filters with ice-cold PBS. The GFC filters were pre-soaked in polyethylenimine and filtered through an harvester apparatus. and [.sup.125I]-α-Bungarotoxin binding was determined by directly counting in a gamma counter.

(369) Data Analysis

(370) The ligand binding data were analyzed by means of nonlinear regression using Prism version 5 (GraphPad Software, Inc., La Jolla, Calif.). The K.sub.i values were calculated from the experimental IC.sub.50 values using the Cheng-Prusoff equation for a single population of competitive sites: K.sub.i=IC.sub.50/[1+(L/K.sub.d)], where L is the concentration of radioligand used in each experiment and the K.sub.d values were determined by saturation binding experiment. All of the assays were performed in duplicate and repeated at least two-three times.

(371) TABLE-US-00001 TABLE 1 Binding Results α4β2 α3β4 Ratio Rat α7 (Ki) Human α7 K(i) CODE COMPOUND Mw nM nM α3β4/α4β2 nM nM Cytisine 190.74  1.27  103 81.1  661.7   690.7 0.89-1.8  70.2-152  363/1206 nM 362-1318 nM Nicotine 162.23 8.6  172 20.0  4.8-15.6 109-274 68 220.27 41  27.5-61.2 8452  4011-17810 206.1 21300   5347-84810 78 296.39 12.5   6.8-22.9 1563  832-2933 125.0 29000    8887-94320 82 208.23  2.87 1.98-4.1  1921 1018-3626 699.3 9760   4689-20340 60 224.69  2.31 1.17-4.6   759  486-1186 328.6  223  94.04-527.5 62 269.14  1.77 0.98-3.2   537  275-1049 303.4  323  69.02-1510  73 280.37 14.1  5.822-34.2  2280  759-6840 161.7 5630   2136-14830 104 340.25 13.4   5.8-31.1 2260 1223-4182 168.7 11900    4432-31870 101 0 340.25  1.24 0.66-2.43 1953 1018-3746 1575.0 5780   3302-10130  4960   1956-12410 103 340.25  3.24 1.32-7.94 2785 1590-4881 859.6 3090  2161-4419 92 311.81 18.5  8.74-39.4 1306  582-2928 70.6 7773   732.3-82500  (query?) 90 347.28 430    153-1209 6080  116-33110 14.1 7879   2910-21330 66 242.7 22.5   5.0-100.8 8951  4083-19620 397.8 12400    5329-28900 81 278.18  6.36 5.37-20.4 9928  4005-24610 1561.0 9680   4992-13090 10270   5163-20420 84 292.2 10.8  5.37-20.4 27500  11170-66270 2546.3 15600    7638-32170 24550   5634-106900 (query) 86 306.23 573    264-1245 3329 1769-6264 5.8 12400    6463-24050 140 215.26  1.84 1.18-2.87  367 196-687 199.5 25600    9971-65750 142 269.73 69   46.7-102.2 2497  739-8434 36.2 21900    9400-51230 149 0 331.2 92.6  55.3-157  13820   2974-64230 149.2 10400    4684-23140 77 294.7 30.9  6.09-156   399 214-745 12.9 1820  762.5-4328  119 248.28  7.29 3.97-13.3 2672 1076-6631 366.5 77500    22320-268800 120 270.71 39.5   15.3-102.4 2281  691-7525 57.7 8890   3617-21860 96 345.83 11.9  3.64-39.4 1066  560-2028 89.6 5610   1391-22620 94 283.76 10.5  5.63-19.5 7886  2796-22240 751.0 14500    3731-57010 144 292.2 90.3    46-177.2 7046  2178-22800 78.0 1030  164.4-6456  154 256.73 3.5 2.28-5.38 26000   4031-167600 7428.0 8080   4992-13090 10600   1739-64410 79 308.73  5.21  0.8-33.6  143 74.6-275  27.4 1040  314.2-3462  127 250.73  0.86 0.52-1.43  611  136-2733 710.5 8970   2302-34950 114 0 328.84 2.9 1.66-5.19  422  159-1124 145.5 5400   1577-18500 112 324.81 8.1  4.8-13.5 1238  547-2801 152.8 3060   591.9-15780  160 431.5  0.238 0.166-0.341   11.9 5-27.8 50.0   26  19.4-35   162 373.6  0.88 0.69-1.18  120 43.8-328  136.4 5450   1676-17740 74 356.3 19.1  7.57-48.4  154  89-268 8.1 10890   1919-61830 116 252.74 14.2   6.9-29.5 1422  419-4820 100.1 40600   10090-163800 118 254.76  3.01 2.06-4.39 5723  2403-13630 1901.3  6928   2276-21080 137 353.85 No data 138 339.82 671.8   194-2326 1785  472-6746 2.7 39810   12990-122000 129 326.82  2.94 1.67-5.81  95  45-198 32.2  3946  1856-8389 110 0 240.73  2.63 1.59-4.36 2273  536-9633 864.3  5027   1071-23590 108 319.79 35.8  20.5-23.8  3233.00 1458-7171 90.3 17080   1972-147900 98* 335.23 160   41.9-627  267200.00  13130-543700 1670.0 54660   10480-285000 122 256.73 36.8  18-75  2685.00  864-8345 73.0 116000    18400-731500 ? 330.86  7.15 4.16-12.2   155.00 70.4-340  21.7 22470   8590-58780 156 544.95 30.2  18.8-48.4  6278.00  1023-38510 207.3 29270   6790-126200 151 320.25 226   81.3-630   23890.00  6020-94800 105.7 250900     5517-1141000 148 297.78 94.1  23.4-378   19270.00  6908-53760 204.8 34150   5669-205700 87 233.32 17.9   4.3-74.2  14950.00  7611-29370 835.2  9804   1255-76600 152 306.23 124.9  35.4-439  100800.00  14770-687400 807.0 89600   19560-410500 124 0 414.85 22.8  16.7-31.1 1402  322-6097 61.5 56190   21780-144900 158 334.64 27.2   5.6-132   2908.00  973-8689 106.9  6593   2235-19450

(372) As can be seen from this data, the compounds of the present invention exhibit high selectivity at the human α4β2 receptor subtypes as compared to both α3β4 subtype and α7 (in both rat cells and human cells, where tested), minimising the likelihood of ‘off-target’ effects.

Example 71—Relative Efficacy at Nicotinic Receptor Subtypes

(373) Compounds of the invention were tested for effects on the function of human α4β2, α3β4 and α7 nicotinic acetylcholine receptors (nAChRs) expressed heterologously in Xenopus oocytes. Human α4β2 nACh receptors were expressed as either (α4).sub.3(β2).sub.2 (low sensitivity for ACh) or (α4).sub.2(β2).sub.3 receptors (high sensitivity for ACh) (Moroni et al., 2006). Expression in oocytes was obtained as follows: pCI (Promega, UK) plasmid containing human α4, β2, β4 or α7 complementary DNA were injected as previously described (Moroni et al., 2006). To express (α4).sub.3(β2).sub.2 nACh receptors, a mixture of 10α4:1β2 cDNAs was injected into the nucleus of oocytes, whereas for (α4).sub.2(β2).sub.3 receptors the cDNA ratio injected was 1α4:10β2.

(374) Functional studies: Recordings were performed manually using a Geneclamp amplifier (Molecular Devices, USA) or using an automated HiClamp system. In both cases the oocytes were impaled with two electrodes filled with 3 M KCl and the cells were held at −60 mV throughout the experiments.

(375) Oocyte isolation and two-electrode voltage-clamp recordings on oocytes were carried out as previously described (Moroni et al., 2006; Carbone et al., 2009). Concentration-response curves for agonists were obtained by normalizing the compounds-induced responses to the responses elicited by 1 mM ACh, a concentration of ACh that maximally activates all the receptors tested (Abin-Carriquiry et al., 2006; Moroni et al., 2006; Carbone et al., 2009). A minimum interval of 5 min was allowed between agonist applications to ensure reproducible recordings. Oocytes were exposed to increasing concentrations of the compounds until no further increases in the response amplitude were obtained. This concentration was taken as the concentration that causes maximal responses on the receptors tested. The data summarised in Tables 1-4 were obtained from at least 5 experiments carried out on oocytes obtained from at least three different donors.

(376) a) Effects of Compounds on (α4).sub.3(β2).sub.2 nAChRs (Low Sensitivity Stoichiometry)

(377) Maximal gating efficacy of the compounds: The concentration of the compounds of the invention causing maximal activation of the (α4).sub.3(β2).sub.2 nAChRs expressed heterologously in Xenopus oocytes was determined using two electrode voltage clamping. The maximal currents elicited by the compounds was relativized to the maximal concentration elicited by 1 mM ACh (which induces maximal responses for (α4).sub.3(β2).sub.2 receptors.

(378) TABLE-US-00002 TABLE 2 Compound Relative efficacy (ACh) ACh 1 Cytisine 0.19 ± 0.07 Varenicline 0.40 ± 0.09 Nicotine 0.48 ± 0.3  69 0.071 ± 0.009 82 0.12 ± 0.02 60 0.110 ± 0.08  62 0.057 ± 0.007 73 0.017 ± 0.019 101 0.009 ± 0.008 103 0.023 ± 0.006 67  0.07 ± 0.009 81  0.007 ± 0.01061 84 0.048 ± 0.040 140 0.050 ± 0.027 119 0.021 ± 0.007 94 0.153 ± 0.006 154 0.013 ± 0.008 127 0.071 ± 0.009 162 0.072 ± 0.026 75 0.011 ± 0.010 118 0.036 ± 0.055 110 0.014 ± 0.007 122 0.058 ± 0.057 156 0.052 ± 0.007 148 0.041 ± 0.057 87 0.011 ± 0.001 152 0.031 ± 0.043 158 0.049 ± 0.012 BS70 0.114 ± 0.113 BS71  0.152 ± 0.1223 BS74 0.126 ± 0.067
b) Effects on (α4).sub.2(β2).sub.3 nAChRS

(379) Maximal gating efficacy of compounds on (α4).sub.2(β2).sub.3 receptors (high sensitivity receptors): The concentration of the compounds causing maximal activation of the (α4).sub.2(β2).sub.3 nAChRs expressed heterologously in Xenopus oocytes was determined using two electrode voltage clamping. The maximal current elicited by the compounds was then relativized to the maximal concentration elicited by 1 mM ACh (which induces maximal responses on (α4).sub.2(β2).sub.3 receptors.

(380) TABLE-US-00003 TABLE 3 Compound Relative efficacy (ACh) ACh 1.0 Cytisine  0.02 ± 0.001 Varenicline 0.14 ± 0.03 Nicotine 0.31 ± 0.07 69  0.009 ± 0.0008 82  0.01 ± 0.001 60  0.01 ± 0.007 62  0.009 ± 0.0001 73 0.030 ± 0.013 101  0.0001 ± 0.00008 103 0.0067 ± 0.0006 67  0.005 ± 0.0001 81 0.024 ± 0.034 84 0.042 ± 0.059 140 0.026 ± 0.036 119 0.0065 ± 0.0005 94  0.001 ± 0.0006 154  0.0001 ± 0.00001 127  0.009 ± 0.0009 162 0.042 ± 0.060 75 0.050 ± 0.071 118 0.062 ± 0.025 110 0.041 ± 0.004 122 0.025 ± 0.000 156 No response 148 0.015 ± 0.021 87 0.023 ± 0.032 158 0.038 ± 0.054 BS74 0.121 ± 0.171
c) Effects of the Compounds on α3β4 nAChRs

(381) Maximal gating efficacy of the compounds on α3β4 nAChRs: The concentration of the compounds causing maximal activation of α3β4 nAChRs expressed heterologously in Xenopus oocytes was determined using two electrode voltage clamping. The maximal currents elicited by the compounds were then relativized to the maximal concentration elicited by 1 mM ACh (which induces maximal responses on α3β4 receptors).

(382) TABLE-US-00004 TABLE 4 Compound Relative efficacy (ACh) ACh 1.0 Cytisine 0.54 ± 0.01 Varenicline 0.51 ± 0.09 Nicotine 0.71 ± 0.07 69 0.044 ± 0.059 82 0.073 ± 0.06  60 0.133 ± 0.017 62 0.184 ± 0.046 73 0.076 ± 0.093 101 0.066 ± 0.056 103 0.016 ± 0.010 67 0.047 ± 0.036 81 0.0210 ± 0.008  84 0.0233 ± 0.005  140 0.172 ± 0.064 119 0.040 ± 0.049 94 0.055 ± 0.047 154 0.093 ± 0.091 127 0.165 ± 0.064 162 0.250 ± 0.077 75 0.120 ± 0.039 118 0.086 ± 0.106 110 0.0708 ± 0.059  122 0.015 ± 0.020 156 0.012 ± 0.007 148 0.034 ± 0.038 87 0.010 ± 0.009 158 0.057 ± 0.016 BS70 0.108 ± 0.149 BS71 0.632 ± 0.067 BS74 1.75 ± 0.56
d) Effects of the Compounds on α7 nAChRs

(383) Relative efficacy of the compounds on α7 nAChRs: The amplitude of currents elicited by the compounds at 100 μM was measured and then relativized to the amplitudes of the responses to 1 mM ACh, the concentration of ACh that causes maximal activation of α7 nAChRs.

(384) TABLE-US-00005 TABLE 5 Compound Relative efficacy (ACh) ACh 1.0 Cytisine   1 ± 0.0.08 Varenicline 0.96 ± 0.03 Nicotine 0.96 ± 0.1  69 0.061 ± 0.09  82 0.18 ± 0.04 60 0.38 ± 0.09 62 0.28 ± 0.01 73 0.0027 ± 0.0021 101 0.16 ± 0.03 103  0.07 ± 0.009 67 No response at 100 μM 94  0.0001 ± 0.00001 154 No response at 100 μM 127 0.17 ± 0.03 75 0.0007 ± 0.0006 118 0.0057 ± 0.0028 110 0.0017 ± 0.0024 122 0.0067 ± 0.0015

(385) The data in Table 5 show that the compounds of the invention exhibit lower relative efficacy on the α7 receptor compared to cytisine and varenicline.