COMPOSITIONS AND METHODS FOR PARASITE CONTROL
20230225323 · 2023-07-20
Assignee
Inventors
- Julia Hoeng (Corcelles, CH)
- Nikolai IVANOV (Neuchâtel, CH)
- Kacper KAMINSKI (Neuchâtel, CH)
- Anatoly MAZUROV (Greensboro, NC, US)
- Sandra SCHORDERET WEBER (Neuchâtel, CH)
Cpc classification
Y02A50/30
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C07D401/04
CHEMISTRY; METALLURGY
A01N43/90
HUMAN NECESSITIES
International classification
A01N43/90
HUMAN NECESSITIES
C07D401/04
CHEMISTRY; METALLURGY
C07D401/12
CHEMISTRY; METALLURGY
Abstract
A compound of Formula I and formulations including such a compound may be used for the reduction of infestation with ectoparasites, in particular ectoparasites of the insect class, including fleas and mosquitoes, and/or ectoparasites of the arachnid class, including ticks and mites, etc. Methods for controlling ectoparasites and/or formulations including such compounds may include use as a repellent, and/or application to a mammal, e.g., a human, dog, cat, cattle, horse, or sheep, or to an object or a fabric. The form may be a topical formulation, a shampoo composition, a cleansing composition, or a treatment composition, preferably a lotion, cream, ointment, gel, foam, patch, powder, solid, sponge, tape, vapor, paste, tincture, or spray.
Claims
1.-15. (canceled)
16. A compound, which is: 2-phenyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine; 2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine; 2,3-dichloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine; 3-ethynyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine; 2-[5-(1,2,3,6-tetrahydropyridin-2-yl)-3-pyridyl]-2,5-diazabicyclo[2.2.1]heptane; 3-[(2S)-4-phenyl-1,2,3,6-tetrahydropyridin-2-yl]pyridine; 3-[(2S)-2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine; 2-methyl-3-(2-phenyl-5-pyridyl)-2-azabicyclo[2.2.2]octane; 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene; 5-(2-chloro-5-pyridyl)-2-methyl-2-azabicyclo[2.2.2]oct-5-ene; 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene; 7-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene; 3-[[(2S)-1,2,3,6-tetrahydropyridin-2-yl]methoxy]pyridine; 2-ethynyl-5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine; 2-methyl-7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene; 7-(2-chloro-5-pyridyl)-2-methyl-2-azabicyclo[2.2.2]oct-5-ene; or 7-(2-ethoxypyridin-5-yl)-2-methyl-2-azabicyclo[2.2.2]oct-5-ene, wherein the compound is optionally in salt or solvate form.
17. A method of reducing an infestation with one or more ectoparasites, the method comprising: exposing the one or more ectoparasites to a compound of formula (I), optionally as a salt or crystal: ##STR00092## wherein X is (i) C—R.sup.1 or N, if the attached to X is a double bond, or (ii) C(R.sup.7).sub.2 or N—R.sup.7, if the
attached to X is a single bond, Y is (i) C—R.sup.8 or N, if one of the
attached to Y is a double bond, or (ii) C(R.sup.8).sub.2 or N—R.sup.8, if none of the
attached to Y is a double bond, R.sup.1 and R.sup.2 are each independently H, halogen, alkyl, haloalkyl, heteroalkyl, alkenyl, alkynyl, optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, or optionally substituted heteroaryl, R.sup.3, R.sup.4, and R.sup.5 are each independently H, halogen, alkyl, haloalkyl, heteroalkyl, alkenyl, alkynyl, optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, or optionally substituted heteroaryl, or wherein R.sup.1 and R.sup.4, or R.sup.3 and R.sup.1, are optionally taken together to form group Z, which is —CH.sub.2—, —CH.sub.2—CH.sub.2—, —CH═CH—, —CH.sub.2—NR.sup.9, —NR.sup.9—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—, and —CH.sub.2—CH.sub.2—NR.sup.9—, —NR.sup.9—CH.sub.2—CH.sub.2—, or —CH.sub.2—NR.sup.9—CH.sub.2—, each R.sup.9 being independently H, alkyl, haloalkyl, or heteroalkyl,
, in each case, independently indicates a single bond or a double bond, A is a bond or -L1-L2-L3-L4-, L1 being connected to the ring comprising X and Y, wherein L1 is a methylene group which is optionally substituted with halogen, alkyl, haloalkyl and/or heteroalkyl, L2 is a bond, —O—, or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, L3 is a bond or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, L4 is a bond or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, R.sup.7 and R.sup.8 are each independently H, alkyl, haloalkyl, or heteroalkyl, and wherein an optional substituent of the optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, and optionally substituted heteroaryl is/are each independently halogen, alkyl, haloalkyl, and/or heteroalkyl.
18. A compound of formula (I), optionally as a salt or crystal, suitable for treating an ectoparasite infestation: ##STR00093## wherein X is (i) C—R.sup.7 or N, if the attached to X is a double bond, or (ii) C(R.sup.7).sub.2 or N—R.sup.7, if the
attached to X is a single bond, Y is (i) C—R.sup.8 or N, if one of the
attached to Y is a double bond, or (ii) C(R.sup.8).sub.2 or N—R.sup.8, if none of the
attached to V is a double bond, R.sup.1 and R.sup.2 are each independently H, halogen, alkyl, haloalkyl, heteroalkyl, alkenyl, alkynyl, optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, or optionally substituted heteroaryl, R.sup.3, R.sup.4, and R.sup.5 are each independently H, halogen, alkyl, haloalkyl, heteroalkyl, alkenyl, alkynyl, optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, or optionally substituted heteroaryl, or wherein R.sup.1 and R.sup.4, or R.sup.3 and R.sup.1, are optionally taken together to form group Z, which is from —CH.sub.2—, —CH.sub.2—CH.sub.2—, —CH═CH—, —CH.sub.2—NR.sup.9, —NR.sup.9—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—, and —CH.sub.2—CH.sub.2—NR.sup.9—, —NR.sup.9—CH.sub.2—CH.sub.2—, or —CH.sub.2—NR.sup.9—CH.sub.2—, each R.sup.9 being independently H, alkyl, haloalkyl, or heteroalkyl,
, in each case, independently indicates a single bond or a double bond, A is a bond or -L1-L2-L3-L4-, L1 being connected to the ring comprising X and Y, wherein L1 is a methylene group which is optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, L2 is a bond, —O—, or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, L3 is a bond or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, L4 is a bond or a methylene group, the methylene group being optionally substituted with halogen, alkyl, haloalkyl, and/or heteroalkyl, R.sup.7 and R.sup.8 are each independently H, alkyl, haloalkyl, or heteroalkyl, and wherein an optional substituent of the optionally substituted cycloalkyl, optionally substituted cycloheteroalkyl, optionally substituted aryl, and optionally substituted heteroaryl is/are each independently halogen, alkyl, haloalkyl, and/or heteroalkyl.
19. The method of claim 17, wherein the ring comprising X and Y comprises only two double bonds.
20. The method of claim 17, wherein the ring comprising X and Y comprises only one double bond.
21. The method of claim 17, wherein the compound of formula (I) has formula (Ig): ##STR00094## wherein R.sup.1, R.sup.2, R.sup.4, R.sup.8, A, X, and Z are as defined for the compound of formula (I).
22. The method of claim 17, wherein the compound of formula (I) has formula (Il): ##STR00095## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.8, A, and X are as defined for the compound of formula (I).
23. The method of claim 17, wherein R.sup.1 is H, halogen, alkyl, haloalkyl, heteroalkyl, alkynyl, cycloalkyl, cycloheteroalkyl, or aryl.
24. The method of claim 17, wherein R.sup.2 is H, halogen, alkyl, haloalkyl, heteroalkyl, alkynyl, cycloalkyl, cycloheteroalkyl, or aryl.
25. The method of claim 17, wherein Z is —CH.sub.2—CH.sub.2—, —CH═CH—, —CH.sub.2—NR.sup.9, —NR.sup.9—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—NR.sup.9—, —NR.sup.9—CH.sub.2—CH.sub.2—, or —CH.sub.2—NR.sup.9—CH.sub.2—.
26. The method of claim 17, wherein L1 is a methylene group which is optionally substituted with halogen and/or alkyl.
27. The method of claim 17, wherein L2 is a bond, —O—, or a methylene group, the methylene group being optionally substituted with halogen and/or alkyl.
28. The method of claim 17, wherein L3 and L4 are each a bond.
29. The method of claim 17, wherein R.sup.7, R.sup.8, and R.sup.9 are each independently H, alkyl, haloalkyl, or heteroalkyl.
30. The method of claim 17, wherein the exposing comprises employing the compound of formula (I) as a repellent, and/or wherein the exposing comprises applying the compound of formula (I) to a mammal.
31. The method of claim 17, wherein the exposing comprises applying the compound of formula (I) as a topical formulation, a shampoo composition, a cleansing composition or a treatment composition.
32. The method of claim 17, wherein the one or more ectoparasites comprise a mosquito or a tick.
33. The method of claim 17, A formulation, comprising: the compound of claim 18; and a carrier.
34. The method of claim 17, wherein R.sup.1 is H, halogen, heteroalkyl, or aryl.
35. The method of claim 17, wherein R.sup.1 is H, halogen, —O-alkyl, or phenyl.
Description
EXAMPLES
Example 1: Mosquito Repellency Assay of Anatabine Derivatives
[0347] Results from other compounds of the present invention are shown in Table 1 and compared to DEET, and were similarly tested as follows:
[0348] The compound of the invention is mixed with ethanol to make a composition that can be applied to a surface and allowed to dry. After the surface is treated with the compounds of the invention and dried, it is heated to human body temperature, and the number of landings and the total time spent by the mosquitoes on the warm surface by adult Aedes aegypti mosquitoes is recorded automatically by machine vision to measure repellency of each compound.
[0349] Repellency (based on the number of individual landings on the warm surface) is expressed as a percentage reduction of the control, where the average number of mosquitoes landing on a warm surface treated only with the vehicle solvent is counted. 100% means no mosquitoes landed on the warm surface.
[0350] For mosquitoes that still landed on the warm surface, the time spent on the warm surface is also recorded and expressed as a percentage of the control, corresponding to the average time that mosquitoes spent on the same warm surface when treated only with the vehicle solvent. 100% mean that the mosquitoes spent the same time on the treated warm surface as on a warm surface treated only with the vehicle solvent.
[0351] Each compound/dose is tested in triplicates using an oil pre-coated glass surface of 132.7 cm and 360 microliters of solution without the compound (the placebo) or with the compound dilution spread on the surface, and allowed to dry before the test. The average and standard error on triplicates is calculated. The control (using only vehicle solvent) is run with ethanol/1% (w/w) dimethylsulfoxide. The same population of mosquitoes is exposed first to the warm surface treated with the vehicle solvent, then to the surface treated with the compound. The concentration of the solution comprising the test compound is adjusted to ensure the treatment dosage of the compound is according to the final concentration per surface unit area in the table.
TABLE-US-00001 TABLE 1 Mean Mean probing time repellency on warm-body Concentration (% compared Standard (% compared Standard Compound [μmol/m.sup.2] to control) deviation to control) deviation exo-3-(3-pyridyl)-2- 75 54.1 33.69 28.87 11.44 azabicyclo[2.2.2]oct-5-ene endo-3-(3-pyridyl)-2- 75 62.93 11.55 67.63 28.45 azabicyclo[2.2.2]oct-5-ene 2-methyl-3-(3-pyridyl)-2- 23.7 56.35 15.81 60.34 2.70 azabicyclo[2.2.2]octane 2-methyl-3-(3-pyridyl)-2- 75 78.00 9.63 9.75 6.66 azabicyclo[2.2.2]octane 3-(1,2,3,6-tetrahydropyridin-2- 75 81.53 8.50 29.86 16.61 yl)pyridine 3-(1,2,5,6-tetrahydropyridin-4- 23.7 57.67 16.95 72.95 29.87 yl)pyridine dihydrochloride 3-(1,2,3,6-tetrahydropyridin-6- 23.7 46.46 16.70 54.70 7.64 yl)pyridine dihydrochloride 2-phenyl-5-(1,2,3,6- 23.7 57.79 14.72 48.79 5.49 tetrahydropyridin-2-yl)pyridine dihydrochloride 2-chloro-5-(1,2,3,6- 23.7 33.51 21.05 69.83 8.64 tetrahydropyridin-2-yl)pyridine dihydrochloride 2,3-dichloro-5-(1,2,3,6- 23.7 48.47 17.24 26.95 12.32 tetrahydropyridin-2-yl)pyridine dihydrochloride 3-ethynyl-5-(1,2,3,6- 23.7 38.91 19.39 63.41 9.26 tetrahydropyridin-2-yl)pyridine dihydrochloride 2-[5-(1,2,3,6-tetrahydropyridin-2- 23.7 30.14 13.38 76.37 22.51 yl)-3-pyridyl]-2,5- diazabicyclo[2.2.1]heptane dihydrochloride 3-[(2S)-4-phenyl-1,2,3,6- 23.7 49.39 6.36 66.30 23.15 tetrahydropyridin-2-yl]pyridine dihydrochloride 3-[(2S)-2-(3-pyridyl)-1,2,3,6- 23.7 47.97 3.52 38.50 3.32 tetrahydropyridin-4-yl]pyridine dihydrochloride 2-methyl-3-(3-pyridinyl)-2- 23.7 69.10 15.76 34.22 14.04 azabicyclo[2.2.2]oct-5-ene 3-(6-chloro-3-pyridyl)-2-methyl- 23.7 38.68 21.11 49.89 8.13 2-azabicyclo[2.2.2]oct-5-ene 3-(6-chloro-3-pyridyl)-2-methyl- 23.7 39.07 23.61 64.60 15.48 2-azabicyclo[2.2.2]octane 2-methyl-3-(6-phenyl-3-pyridyl)- 23.7 57.06 16.57 43.54 8.76 2-azabicyclo[2.2.2]octane hydrochloride 5-(3-pyridyl)-2- 23.7 50.40 11.05 84.14 44.59 azabicyclo[2.2.2]oct-5-ene 2-methyl-5-(3-pyridyl)-2- 23.7 82.32 3.68 44.15 13.01 azabicyclo[2.2.2]oct-5-ene 5-(6-chloro-3-pyridyl)-2- 23.7 41.31 20.28 70.65 16.31 azabicyclo[2.2.2]oct-5-ene hydrochloride 5-(6-chloro-3-pyridyl)-2-methyl- 23.7 68.25 15.93 46.57 9.04 2-azabicyclo[2.2.2]oct-5-ene 7-(3-pyridyl)-2- 23.7 60.39 13.79 51.47 20.46 azabicyclo[2.2.2]oct-5-ene 7-(6-chloro-3-pyridyl)-2- 23.7 57.82 15.85 59.26 27.60 azabicyclo[2.2.2]oct-5-ene 3-(2-piperidylmethoxy)pyridine 23.7 54.17 15.40 59.79 11.59 3-[[(2S)-1,2,3,6- 23.7 65.00 11.75 66.81 4.19 tetrahydropyridin-2- yl]methoxy]pyridine 2-ethynyl-5-[2-(3-pyridyl)-1,2,3,6- 23.7 48.17 16.69 57.72 18.59 tetrahydropyridin-4-yl]pyridine 2-methyl-7-(3-pyridyl)-2- 23.7 51.61 2.82 47.77 6.86 azabicyclo[2.2.2]oct-5-ene 7-(6-chloro-3-pyridyl)-2-methyl- 23.7 59.30 8.83 53.84 12.74 2-azabicyclo[2.2.2]oct-5-ene 7-(6-ethoxypyridin-3-yl)-2- 23.7 77.45 2.31 39.97 5.95 methyl-2-azabicyclo[2.2.2]oct-5- ene N,N-diethyl-3-methyl-benzamide, 23.7 75.21 5.59 19.80 10.61 DEET
Example 2: Tick Repellency Assay and Acaricidal Activity of Anatabine Derivatives
[0352] The test for repellency of compounds to ticks relies on their questing behavior. Ticks will explore their habitat to find a suitable host hunting site and try to avoid areas treated with repellent or irritating substances. The compounds of the invention are dissolved in dimethylsulfoxide (DMSO) and then diluted with ethanol to make a composition containing a maximum of 1% (w/w) DMSO, which is suitable for achieving the stated concentration per unit area on the applied surface. The composition or control is applied to the treatment area and allowed to dry. A circular arena of 8.96 cm2 from which ticks cannot escape is used for the assay. Only one quadrant (2.25 cm2) is treated with the test compound or control, while the rest is left untreated. 30 to 60 Rhipicephalus sanguineus tick larvae are deposited in the non-treated area of the circular arena. After 1 minute, the change in position of the ticks in the treated and untreated areas is measured for a duration of 2 minutes. A visual recording device, such as a camera, records the test area, from which number of movements in the treated and untreated areas can be counted and reported as number of tick movements. If the compound shows repellent activity, ticks will avoid walking on the treated quadrant. Repellency is expressed as: 1−M.sub.T/M.sub.U)×100, where M.sub.T is the number of tick movements within the treated area, and M.sub.U is the number of tick movements within the untreated area. 100% means that all the ticks completely avoided the treated surface. The potential acaricidal activity of the test compounds is measured in the same setup over a duration of 8 minutes and the knockdown activity is expressed in % motility reduction between the beginning and the end of the 8 minutes.
TABLE-US-00002 TABLE 2 Mean Knockdown Concentration repellency Standard activity Standard Compound [μmol/m.sup.2] (%) deviation (%) deviation exo-3-(3-pyridyl)-2- 89 73.50 23.64 41.93 12.40 azabicyclo[2.2.2]oct-5-ene 28.1 52.33 15.47 18.67 4.61 endo-3-(3-pyridyl)-2- 89 63.43 8.06 73.07 6.65 azabicyclo[2.2.2]oct-5-ene 28.1 24.43 12.29 15.67 8.70 2-methyl-3-(3-pyridyl)-2- 89 96.23 4.47 6.70 11.60 azabicyclo[2.2.2]octane 28.1 78.80 5.38 0.00 0.00 3-(1,2,3,6- 89 66.63 10.51 45.23 2.67 tetrahydropyridin-2- 28.1 15.10 13.16 10.47 4.54 yl)pyridine 3-(1,2,5,6- 89 95.43 1.08 5.43 9.41 tetrahydropyridin-4- 28.1 80.17 5.60 16.20 8.85 yl)pyridine dihydrochloride 3-(1,2,3,6- 89 50.40 28.46 0.00 0.00 tetrahydropyridin-6- 28.1 37.33 38.18 0.00 0.00 yl)pyridine dihydrochloride 2-phenyl-5-(1,2,3,6- 89 77.50 21.23 0.00 0.00 tetrahydropyridin-2- 28.1 82.93 6.40 0.00 0.00 yl)pyridine dihydrochloride 2-chloro-5-(1,2,3,6- 89 100.00 0.00 0.00 0.00 tetrahydropyridin-2- 28.1 98.87 1.79 0.00 0.00 yl)pyridine dihydrochloride 2,3-dichloro-5-(1,2,3,6- 89 100.00 0.00 2.50 3.50 tetrahydropyridin-2- 28.1 100.00 0.00 0.00 0.00 yl)pyridine dihydrochloride 3-ethynyl-5-(1,2,3,6- 89 93.93 8.99 0.00 0.00 tetrahydropyridin-2- 28.1 92.63 12.76 0.00 0.00 yl)pyridine dihydrochloride 2-[5-(1,2,3,6- 89 74.00 15.34 0.00 0.00 tetrahydropyridin-2-yl)-3- 28.1 66.33 18.64 0.00 0.00 pyridyl]-2,5- diazabicyclo[2.2.1]heptane dihydrochloride 3-[(2S)-4-phenyl-1,2,3,6- 89 80.63 17.76 0.00 0.00 tetrahydropyridin-2- 28.1 88.20 6.18 0.00 0.00 yl)pyridine dihydrochloride 3-[(2S)-2-(3-pyridyl)- 89 51.73 30.96 0.00 0.00 1,2,3,6-tetrahydropyridin- 28.1 81.37 3.19 1.63 2.83 4-yl]pyridine dihydrochloride 2-methyl-3-(3-pyridinyl)-2- 89 96.47 3.50 0.00 0.00 azabicyclo[2.2.2]oct-5-ene 28.1 91.37 7.23 0.00 0.00 3-(6-chloro-3-pyridyl)-2- 89 54.27 48.71 0.00 0.00 methyl-2- 28.1 29.67 29.61 0.00 0.00 azabicyclo[2.2.2]oct-5-ene 3-(6-chloro-3-pyridyl)-2- 89 67.00 12.57 0.00 0.00 methyl-2- 28.1 41.97 34.07 0.00 0.00 azabicyclo[2.2.2]octane 2-methyl-3-(6-phenyl-3- 89 26.77 29.95 7.20 12.47 pyridyl)-2- 28.1 42.23 27.11 0.00 0.00 azabicyclo[2.2.2]octane hydrochloride 5-(3-pyridyl)-2- 89 58.40 6.05 2.83 4.40 azabicyclo[2.2.2]oct-5-ene 28.1 60.47 34.48 0.00 0.00 2-methyl-5-(3-pyridyl)-2- 89 39.83 34.63 3.53 4.36 azabicyclo[2.2.2]oct-5-ene 28.1 46.23 44.82 0.00 0.00 5-(6-chloro-3-pyridyl)-2- 89 39.67 34.42 6.40 9.09 azabicyclo[2.2.2]oct-5-ene 28.1 44.37 19.62 0.00 0.00 hydrochloride 5-(6-chloro-3-pyridyl)-2- 89 27.53 26.31 2.40 2.95 methyl-2- 28.1 25.03 9.59 0.00 0.00 azabicyclo[2.2.2]oct-5-ene 7-(3-pyridyl)-2- 89 59.07 20.06 9.27 8.20 azabicyclo[2.2.2]oct-5-ene 28.1 15.50 13.03 1.57 2.71 7-(6-chloro-3-pyridyl)-2- 89 21.20 28.50 4.93 4.31 azabicyclo[2.2.2]oct-5-ene 28.1 33.53 29.04 0.00 0.00 3-(2- 89 91.00 10.75 14.37 5.18 piperidylmethoxy)pyridine 28.1 75.50 4.20 0.00 0.00 3-[[(2S)-1,2,3,6- 89 78.47 5.51 6.27 10.85 tetrahydropyridin-2- 28.1 68.53 3.93 3.37 3.62 yl]methoxy]pyridine 2-ethynyl-5-[2-(3-pyridyl)- 89 79.03 9.15 1.20 2.08 1,2,3,6-tetrahydropyridin- 28.1 75.80 6.54 3.33 5.77 4-yl]pyridine 2-methyl-7-(3-pyridyl)-2- 89 81.20 3.18 4.63 8.03 azabicyclo[2.2.2]oct-5-ene 28.1 51.60 3.61 6.77 6.65 7-(6-chloro-3-pyridyl)-2- 89 97.83 3.75 3.57 6.18 methyl-2- 28.1 86.30 8.82 7.40 7.03 azabicyclo[2.2.2]oct-5-ene 7-(6-ethoxypyridin-3-yl)-2- 89 74.50 22.27 15.73 7.66 methyl-2- 28.1 78.03 16.77 17.90 6.15 azabicyclo[2.2.2]oct-5-ene N,N-diethyl-3-methyl- 89 100.00 0.00 0.00 0.00 benzamide,DEET 28.1 91.83 3.79 0.00 0.00 Ethyl alcohol/1% 100 33.17 28.34 0.00 0.00 dimethylsulfoxide (control)
[0353] The following table provides an overview of the compounds whose synthesis will be described hereinbelow:
TABLE-US-00003 No. structure chemical name 1
[0354] Compounds 1-3 were synthesized by SpiroChem, compound 5 was purchased from Enamine, compounds 4, 7-29 were obtained by WuXi Apptec Co., Ltd., N,N-diethyl-3-methyl-benzamide was purchased from Sigma-Aldrich.
##STR00064##
[0355] Diethyl (pyridin-3-ylmethylene)dicarbamate. p-Toluenesulfonic acid (5.00 g, 26.3 mmol) was added to a solution of ethyl carbamate (33.27 g, 373.4 mmol) and nicotinaldehyde (17.53 mL, 186.7 mmol) in benzene (400 mL). The solution was stirred at strong reflux with a Dean Stark apparatus (overnight). A precipitate formed during the reaction. The reaction mixture was cooled to 0° C. and the material was filtrated. It was further washed twice with diethyl ether to afford a colorless solid (6.2 g, 88%).
[0356] Ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. Cyclohexa-1,3-diene (1.57 mL, 16.46 mmol) was added to a solution of diethyl (pyridin-3-ylmethylene)dicarbamate (4.00 g, 14.97 mmol) in acetic acid (30 mL). Boron trifluoride acetic acid complex (17.04 mL, 122.7 mmol) was added and the tube was sealed and heated at 80° C. for 3 h. The mixture was then poured at 0° C. into a sodium hydroxide solution (6M) to reach pH=14. The aqueous layer was then extracted with dichloromethane (3times). The organic layers were dried over sodium sulfate, filtered and evaporated. The residue was purified by flash chromatography using a 50 to 100% ethyl acetate/cyclohexane gradient to afford an orange to brown oil as a mixture exo/endo-isomers (0.650 g, 17%). .sup.1H NMR (400 MHz, chloroform-d) δ 8.47-8.55 (m, 2H), 7.52-7.60 (m, 1H), 7.20-7.26 (m, 1H), 6.38-6.40 (in, 0.45H), 6.24-6.30 (in, 0.55H), 4.76 (s, 0.55H), 4.68 (s, 0.45H), 4.44 (t, J=5.2 Hz, 0.45H), 4.34 (t, J=5.2 Hz, 0.55H), 3.91-4.12 (m, 2H), 2.50-2.60 (m, 1H) 2.40-2.45 (m, 2H), 2.08-2.20 (m, 1H), 1.70-1.76 (m, 1H), 1.27 (t, J=7.1 Hz, 2H), 0.95 (t, J=7.1 Hz, 1H).
[0357] 3-(Pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. KOH (3.30 g, 59.00 mmol) was added to ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate in diglyme (10 mL). The tube was sealed and the solution was heated under microwave 30 min at 160° C. The volatiles were evaporated. Water and dichloromethane were added to the residue and the pH was adjusted to 8-9 with 2M hydrochloric acid. The layers were separated and the aqueous layer was washed with dichloromethane. The organic layers were combined and concentrated under vacuum. The residue was purified by chromatography column using dichloromethane—methanol gradient 1:0 to 4:1 as eluent.
[0358] Compound 1: .sup.1H NMR (400 MHz, chloroform-d) δ 8.53 (d, J=1.8 Hz, 1H), 8.40 (d, J=5.0 Hz, 1H), 7.70 (dt, J=8.05, 1.80, 1H), 7.16-7.20, (m, 1H), 5.95-5.99 (m, 1H), 5.55-5.59 (m, 1H), 4.15 (s, 1H), 3.68 (t, J=5.0 Hz, 1H), 2.95-3.05 (br s, 2H), 2.47-2.18 (m, 3H), 1.99-2.02 (m, 1H), 1.73 (d, J=8.0 Hz, 1H).
[0359] Compound 2: .sup.1H NMR (400 MHz, chloroform-d) δ 8.64 (d, J=1.8 Hz, 1H), 8.45 (d, J=5.0 Hz, 1H), 7.75 (dt, J=8.05, 1.80, 1H), 7.16-7.20, (m, 1H), 6.22-6.18 (m, 1H), 5.58-5.62 (m, 1H), 4.56 (s, 1H), 3.78 (t, J=5.0 Hz, 1H), 2.23-2.53 (m, 2H), 1.84-2.10 (m, 4H), 1.60 (d, J=8.0 Hz, 1H)
##STR00065##
[0360] 2-Methyl-3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. An ether solution of ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate was added to an ether solution of lithium aluminum hydride. The solution was stirred at reflux (6h). Water was added and the organic layer was extracted with dichloromethane (3×). The organic layers were combined, dried over Na.sub.2SO.sub.4 and under vacuum. The residue was purified by flash chromatography using a 0 to 10% dichloromethane—methanol gradient to afford brown oil as a mixture of exo/endo isomers (0.150 g, 48%). .sup.1H NMR (400 MHz, chloroform-d) δ 8.59 (d, J=1.8 Hz, 1H), 8.40 (d, J=5.0 Hz, 1H), 7.67 (dt, J=8.05, 1.80, 1H), 7.17, (dd, J=7.8, 4.6 Hz, 1H), 5.84-5.91 (m, 1H), 5.68-5.74 (m, 1H), 3.35 (t, J=4.8 Hz, 1H), 3.07 (s, 1H), 2.29-2.39 (m, 1H), 2.25 (s, 3H), 2.17-2.23 (m, 1H), 2.06-2.16 (m, 2H), 1.65 (m, 1H).
[0361] 2-Methyl-3-(pyridin-3-yl)-2-azabicyclo[2.2.2]octane. Palladium on carbon (Pd/C) (10 wt. % loading, 8 mg) was added to an ethyl acetate solution of 2-methyl-3-(pyridin-3-yl)-2 azabicyclo[2.2.2]oct-5-ene (80 mg, 0.04 mmol). The solution was stirred 5 h under hydrogen atmosphere (1 atm). Pd/C was filtered and the pad of Celite was washed with ethyl acetate. Pd/C (8 mg) was added to the solution, and the mixture was stirred 16 h under hydrogen atmosphere (1 atm). Pd/C was filtered and the pad of Celite was washed with ethyl acetate. The volatiles were evaporated leading to 2-methyl-3-(pyridin-3-yl)-2-azabicyclo[2.2.2]octane (78 mg, quant.).
[0362] .sup.1H NMR (400 MHz, chloroform-d) δ 8.32-8.37 (m, 2H), 7.37-7.42 (m, 1H), 7.12-7.22 (m, 1H), 2.40-2.55 (m, 1H), 2.31 (s, 3H), 2.17-2.28 (m, 1H), 1.80-1.45 (m, 7H), 1.10-1.20 (m, 1H) 0.75-0.95 (m, 2H).
##STR00066##
[0363] 1,1-Diphenyl-N-(3-pyridylmethyl)methanimine. To a solution of 3-(aminomethyl)pyridine (500 g, 2.74 mol) in toluene (2000 mL) was added p-toluenesulfonic acid (47.2 g, 274 mmol) and benzophenone (374 g, 3.46 mol, 350 mL). The mixture was stirred at 110° C. for 12 hr. TLC (petroleum ether:ethyl acetate=3:1) showed 3-(aminomethyl)pyridine (Rf=0.8) was consumed, and a new major spot (Rf=0.5) formed. The reaction mixture was concentrated under reduced pressure to remove toluene. The residue was diluted with ethyl acetate (500 mL) and filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 1.5 kg SepaFlash® Silica Flash column, eluent of 0˜30% ethyl acetate/petroleum ether gradient, flow rate 200 mL/min). 1,1-Diphenyl-N-(3-pyridylmethyl)methanimine (500 g, 1.80 mol, 65.6% yield, 98.1% purity) was obtained as a yellow oil; TLC (petroleum ether:ethyl acetate, 3:1, product Rf=0.5; m/z=273.3 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.48-8.47 (m, 1H), 8.43-8.42 (m, 1H), 7.65-7.60 (m, 3H), 7.43-7.41 (m, 1H), 7.33-7.29 (m, 2H), 7.27-7.14 (m, 1H), 7.14-7.12 (m, 2H), 4.53 (s, 2H).
[0364] 3-(1,2,3,6-Tetrahydropyridin-2-yl)pyridine. To a mixture of 1,1-diphenyl-N-(3-pyridylmethyl)methanimine (500 g, 1.84 mol) in tetrahydrofuran (1.00 L) was added lithium diisopropylamide (2 M, 1.00 L) at −78° C. After addition, the mixture was stirred at −60° C. for 30 min. Then to the mixture was added cis-1,4-dichloro-2-butene (364 g, 2.91 mol, 305 mL) at −60° C. After addition, the mixture was stirred at −60° C. for 1 hr. The mixture was quenched with 2 N HCl (300 mL) and stirred at 25° C. for 30 min. Then the mixture was extracted with methyl tert-butyl ether (500 mL×3). Then the aqueous water phase was basified with solid K.sub.2CO.sub.3 to pH=12. The water phase was stirred at 25° C. for 2 hr. Then the water phase was extracted with dichloromethane (1 L×5). The combined dichloromethane phases were washed with brine (2 L) and concentrated under reduced pressures to afford an oil residue. TLC (ethyl acetate—methanol=10:1) showed a main new spot was found (Rf=0.2). The oil was purified with chromatography column (silica gel, petroleum ether—ethyl acetate, 1:0 and ethyl acetate—methanol, 10:1, Rf=0.2). Obtained crude material was purified with reverse chromatography (NH.sub.4ON, CH.sub.3CN) to give 3-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (52.0 g, 318 mmol, 17.3% yield, 98.1% purity); m/z (M+H).sup.+=161; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.55 (d, J=2.0 Hz, 1H), 8.44 (dd, J=1.6, 4.8 Hz, 1H), 7.66 (td, J=1.6, 7.6 Hz, 1H), 7.30-7.11 (m, 1H), 5.89-5.60 (m, 2H), 3.83 (t, J=7.2 Hz, 1H), 3.64-3.33 (m, 2H), 2.28-2.14 (m, 2H).
##STR00067##
[0365] Trimethylsilylbut-3-yn-1-ol. To a solution of but-3-yn-1-ol (10.0 g, 142 mmol, 10.8 mL, 1.00 eq.) in tetrahydrofuran (100 mL) was added tert-butyl lithium (2.5 M, 85.5 mL, 1.50 eq.) at −60° C., the mixture was stirred for 1 hr. Then trimethylsilyl chloride (20.1 g, 185 mmol, 23.4 mL, 1.30 eq.) was added at −60° C. The mixture was stirred at 0° C. for 2 hrs. The reaction mixture was quenched by addition of saturated aqueous solution of NH.sub.4Cl (10 mL) at 0° C., and then diluted with water (50 mL) and extracted with ethyl acetate (100 mL×2). The combined organic layers were washed with brine (100 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 120 g SepaFlash® Silica Flash Column, Eluent of 0˜30% ethyl acetate/petroleum ether gradient, flow rate 60 mL/min) to give 4-trimethylsilylbut-3-yn-1-ol (9.40 g, 66.0 mmol, 46.3% yield) as colorless oil; .sup.1HNMR (400 MHz, CDCl.sub.3) δ 3.71 (m, 2H), 2.51 (m, 2H), 0.16 (s, 9H).
[0366] 4-Trimethylsilylbut-3-en-1-ol. To a solution of 4-trimethylsilylbut-3-yn-1-ol in methyl tert-butyl ether (100 mL) was added diisobutylaluminium hydride (1 M, 189 mL, 3.00 eq.) at 0° C. The mixture was stirred at 0° C. for 30 min. The reaction was heated at 60° C. 12 hrs. The reaction mixture was quenched by addition of H.sub.2SO.sub.4 (2M, 100 ml) at 0° C., then the mixture was filtered through Celite and diluted with water (100 mL) and extracted with ethyl acetate (100 mL×2). The combined organic layers were washed with brine (100 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give 4-trimethylsilylbut-3-en-1-ol (7.00 g, crude) as yellow oil. .sup.1HNMR (400 MHz, CDCl.sub.3) δ 6.33-6.26 (m, 1H), 5.71-5.68 (d, J=12 Hz, 1H), 3.70-3.67 (m, 2H), 2.43-2.41 (m, 2H), 0.14 (s, 9H).
[0367] 4-Trimethylsilylbut-3-enyl 4-methylbenzenesulfonate. To a solution of 4-trimethylsilylbut-3-en-1-ol (7.00 g, 48.5 mmol, 1.00 eq.) in dichloromethane (80 mL) was added 4-dimethylaminopyridine (3.50 g, 28.6 mmol, 0.591 eq.) and 4-methylbenzenesulfonyl chloride (11.1 g, 58.2 mmol, 1.20 eq.), triethylamine (4.90 g, 48.4 mmol, 6.74 mL, 0.998 eq.) The mixture was stirred at 0° C. for 2 hrs. The residue was diluted with water (40 mL) and extracted with dichloromethane (20 mL×2). The combined organic layers were washed with brine (40 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO.sub.2, petroleum ether/ethyl acetate=80/1) to give 4-trimethylsilylbut-3-enyl 4-methylbenzenesulfonate (11.3 g, 37.8 mmol, 78.0% yield) as colorless oil. .sup.1HNMR (400 MHz, DMSO-d.sub.6) δ 7.78-7.76 (d, J=8.2 Hz, 2H), 7.49-7.47 (m, 2H), 6.14-6.07 (m, 1H), 5.59-5.55 (d, J=14.0 Hz, 1H), 4.06-4.02 (m, 2H), 2.50-2.42 (s, 2H), 0.05 (s, 9H).
[0368] 1-Azido-4-trimethylsilylbut-3-ene. To a solution of 4-trimethylsilylbut-3-enyl 4-methylbenzenesulfonate (11.3 g, 37.8 mmol, 1.00 eq.) in N,N-dimethylformamide (120 mL) was added NaN.sub.3 (5.66 g, 87.0 mmol, 2.50 eq.) at 25° C. The mixture was stirred at 60° C. for 2 hr. The reaction mixture was diluted with water (60 mL) and extracted with ethyl acetate (100 mL×2). The combined organic layers were washed with brine (100 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give 1-azido-4-trimethylsilylbut-3-ene (5.30 g, crude) as colorless oil. .sup.1HNMR (400 MHz, DMSO-d.sub.6) δ 6.31-6.24 (m, 1H), 5.64-5.60 (d, J=14.5 Hz, 1H), 3.37 (t, J=6.78 Hz, 1H), 2.40-2.35 (m, 2H), 0.12 (s, 9H).
[0369] 1-Amino-4-trimethylsilylbut-3-ene. To a solution of 1-azido-4-trimethylsilylbut-3-ene (4.50 g, 26.5 mmol, 1.00 eq.) in methyl tert-butyl ether (50 mL) was added lithium aluminum hydride (1.21 g, 31.9 mmol, 1.20 eq.) at 0° C. The mixture was stirred at 0° C. for 2 hrs. To the mixture was added water (1 ml), then was added NaOH (15%, 1 ml) and water (3 ml) at 0° C., dried over Na.sub.2SO.sub.4, filtered and the filtrate was used in the next step. 1-Amino-4-trimethylsilylbut-3-ene (3.00 g, crude) was obtained as yellow oil.
[0370] 1-(3-Pyridyl)-N-(4-trimethylsilylbut-3-enyl)methanimine. To a solution of 1-amino-4-trimethylsilylbut-3-ene (3.00 g, 20.9 mmol, 1.00 eq.) in methyl tert-butyl ether (5 mL) was added MgSO.sub.4 (17.6 g, 146 mmol, 7.00 eq.) and 3-pyridinecarboxaldehyde (2.24 g, 20.9 mmol, 1.97 mL, 1.00 eq.). The mixture was stirred at 25° C. for 0.5 hr. The reaction mixture was then filtered and concentrated under reduced pressure The residue was purified by reverse phase chromatography (base condition) to get 1-(3-pyridyl)-N-(4-trimethylsilylbut-3-enyl)methanimine (2.00 g, 8.61 mmol, 41.0% yield) as yellow oil. .sup.1HNMR (400 MHz, CDCl.sub.3) δ 8.86-8.85 (m, 1H), 8.65-8.64 (m, 1H), 8.31-8.30 (m, 1H), 8.12-8.10 (m, 1H), 7.36-7.27 (m, 1H), 6.34-6.29 (m, 1H), 5.63-5.59 (m, 1H), 3.73-3.70 (m, 2H), 2.56-2.53 (m, 2H), 0.12 (m, 9H).
[0371] 3-(1,2,3,6-Tetrahydropyridin-6-yl)pyridine. To a solution of 1-(3-pyridyl)-N-(4-trimethylsilylbut-3-enyl)methanimine (2.00 g, 8.61 mmol, 1.00 eq) in acetonitrile (5 mL) was added Sc(OTf).sub.3 (8.47 g, 17.21 mmol, 2.00 eq.). The mixture was stirred at 60° C. for 12 hrs. The reaction mixture was adjusted to pH 9-111. The residue was diluted with water (10 mL) and extracted with dichloromethane (20 mL×2). The combined organic layers were washed with brine (10 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by prep-HPLC (basic condition: column: Waters X bridge C18 150×50 mm, 10 μm; mobile phase: [water (10 mM NH.sub.4HCO.sub.3)-acetonitrile]; B %: 5%-30%, 11 min) to give 3-(1,2,3,6-tetrahydropyridin-6-yl)pyridine (102 mg, 7.25% yield, 98.7% purity) as yellow oil; m/z=161.2 (M+1).sup.+; .sup.1HNMR (400 MHz, CDCl.sub.3) δ 8.60-8.59 (d, J=2.1 Hz, 1H), 8.53-8.52 (dd, J=4.7 Hz, 1H), 7.72-7.70 (m, 1H), 7.28-7.25 (m, 1H), 6.02-5.99 (ddt, J=7.6 Hz 1H), 5.73-5.70 (dd, J=10.1 Hz, 1H), 4.52-4.51 (s, 1H), 3.09-3.00 (m, 2H), 2.26-2.24 (m, 1H), 2.13-2.05 (m, 1H). 3-(1,2,3,6-Tetrahydropyridin-6-yl)pyridine was converted into dihydrochloride salt by treatment with hydrogen chloride solution in diethyl ether.
##STR00068##
[0372] N-[(6-Chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine. To a solution of (6-chloro-3-pyridyl)methanamine (2.00 g, 11.0 mmol, 1.00 eq), benzophenone (1.57 g, 11.0 mmol, 1.00 eq) in toluene (20 mL) was added p-toluenesulfonic acid (418 mg, 2.20 mmol, 0.200 eq). The mixture was stirred at 110° C. for 10 hrs. The mixture was concentrated. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=1/0 to 5/1) to get the spot (petroleum ether/ethyl acetate=5/1, Rf=0.5). N-[(6-Chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine (1.20 g, crude) was obtained as a colorless oil; m/z=307.0 (M+1).sup.+.
[0373] 2-Chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of N-[(6-chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine (982 mg, 3.20 mmol, 1.00 eq) in tetrahydrofuran (10 mL) was added lithium diisopropylamide (2 M, 3.20 mL, 2.00 eq) at −70° C. The mixture was stirred at −70° C. for 0.5 hr and then cis-1,4-dichloro-2-butene (0.400 g, 3.20 mmol, 336 uL, 1.00 eq) was added. The mixture was stirred at 25° C. for 3 hrs. The mixture was quenched with HCl (1 M) (50 mL) and stirred for 0.5 h. Then adjusted pH to 12 with NaOH solution (40%) and extracted with dichloromethane (20 mL×3). The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by reversed phase (HCl condition, ISCO®; 40 g SepaFlash® Silica Flash Column, eluent of 0-20% acetonitrile/water, flow rate 40 mL/min) to get 2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (100.48 mg, 373 umol, 11.7% yield, 99.4% purity) as a white solid; m/z=195.3 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 8.56-8.55 (d, J=2.8, 1H), 8.05-8.02 (m, 1H), 7.62-7.60 (d, J=8.4, 1H), 6.11-5.89 (m, 2H), 4.66-4.54 (m, 1H), 3.99-3.78 (m, 2H), 2.80-2.64 (m, 2H).
[0374] N-tert-Butyloxycarbonyl-2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of 2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (100 mg, 513 umol, 1.00 eq) and triethylamine (104 mg, 1.03 mmol, 143 uL, 2.00 eq) in dichloromethane (5 mL) was added di-tert-butyl dicarbonate (135 mg, 616 umol, 142 uL, 1.20 eq). The mixture was stirred at 25° C. for 10 hrs. The mixture was washed with water (20 mL), brine (20 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=10/1 to 5/1) to get the product (petroleum ether/ethyl acetate=5/1, Rf=0.6) as a yellow oil; m/z=295.3 (M+1).sup.+.
[0375] N-tert-Butyloxycarbonyl 2-phenyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of N-tert-butyloxycarbonyl-2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (160 mg, 543 umol, 1.00 eq), phenylboronic acid (80 mg, 656 umol, 1.21 eq) and Na.sub.2CO.sub.3 (2 M, 542 uL, 2.00 eq) in toluene (5 mL) and ethanol (1 mL) was added Pd(PPh.sub.3).sub.4 (314 mg, 271 umol, 0.0500 eq). The mixture was stirred at 90° C. for 3 hrs under N.sub.2. The mixture was filtered and the filtrate was poured into water (20 mL) and extracted with ethyl acetate (10 mL×2). The combined organic layers were washed with brine (10 mL), dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20/1 to 5/1) to get the product (petroleum ether/ethyl acetate=5/1, Rf=0.65), (170 mg, 505 umol, 93.1% yield) as a colorless oil; m/z=337.4 (M+1).sup.+.
[0376] 2-Phenyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. A mixture of N-tert-butyloxycarbonyl 2-phenyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (170 mg, 505 umol, 1.00 eq), hydrogen chloride solution in ethyl acetate (4 M, 2 mL, 15.8 eq) in ethyl acetate (5 mL) was stirred at 25° C. for 1 hr. The mixture was filtered and the filter cake was washed with EtOAc (20 mL), collected and concentrated to get 2-phenyl-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (67.86 mg, 218 umol, 43.1% yield, 99.3% purity) as off-white solid; m/z=237.2 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 9.01-9.00 (d, J=2.0, 1H), 8.67-8.65 (m, 1H), 8.43-8.41 (m, 1H), 8.03-8.07 (m, 2H), 7.72-7.67 (m, 3H), 6.15-5.94 (m, 2H), 4.05-3.86 (m, 2H), 2.92-2.73 (m, 2H).
##STR00069##
[0377] N-[(6-Chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine. To a solution of (6-chloro-3-pyridyl)methanamine (2.00 g, 11.0 mmol, 1.00 eq), benzophenone (1.57 g, 11.0 mmol, 1.00 eq) in toluene (20 mL) was added p-toluenesulfonic acid (418 mg, 2.20 mmol, 0.200 eq). The mixture was stirred at 110° C. for 10 hrs. The mixture was concentrated. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=1/0 to 5/1) to get the spot (petroleum ether/ethyl acetate=5/1, Rf=0.5). N-[(6-Chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine (1.20 g, crude) was obtained as a colorless oil; m/z=307.0 (M+1).sup.+.
[0378] 2-Chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of N-[(6-chloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine (982 mg, 3.20 mmol, 1.00 eq) in tetrahydrofuran (10 mL) was added lithium diisopropylamide (2 M, 3.20 mL, 2.00 eq) at −70° C. The mixture was stirred at −70° C. for 0.5 hr and then cis-1,4-dichloro-2-butene (0.400 g, 3.20 mmol, 336 uL, 1.00 eq) was added. The mixture was stirred at 25° C. for 3 hrs. The mixture was quenched with HCl (1 M) (50 mL) and stirred for 0.5 h. Then adjusted pH to 12 with NaOH solution (40%) and extracted with dichloromethane (20 mL×3). The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by reversed phase (HCl condition, ISCO®; 40 g SepaFlash® Silica Flash Column, eluent of 0˜20% acetonitrile/water, flow rate 40 mL/min) to get 2-chloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (100.48 mg, 373 umol, 11.7% yield, 99.4% purity) as a white solid; m/z=195.3 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 8.56-8.55 (d, J=2.8, 1H), 8.05-8.02 (m, 1H), 7.62-7.60 (d, J=8.4, 1H), 6.11-5.89 (m, 2H), 4.66-4.54 (m, 1H), 3.99-3.78 (m, 2H), 2.80-2.64 (m, 2H).
##STR00070##
[0379] 2-[(5,6-Dichloro-3-pyridyl)methyl]isoindoline-1,3-dione. To a solution of (5,6-dichloro-3-pyridyl)methanol (5.00 g, 28.1 mmol, 1.00 eq), phthalimide (4.13 g, 28.1 mmol, 1.00 eq) and PPh.sub.3 (11.1 g, 42.1 mmol, 1.50 eq) in tetrahydrofuran (50 mL) was added diethyl azodicarboxylate (7.34 g, 42.1 mmol, 7.66 mL, 1.50 eq) at 0° C. The mixture was stirred at 25° C. for 10 hrs. The mixture was poured into water (200 mL) and then extracted with ethyl acetate (200 mL×3). The combined organic layers were washed with brine (500 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=50/1 to 5/1) to get 2-[(5,6-dichloro-3-pyridyl)methyl]isoindoline-1,3-dione (petroleum ether/ethyl acetate=3/1, Rf=0.6), (6.00 g, 17.6 mmol, 62.6% yield, 90% purity) as a yellow solid; m/z=307.0 (M+1).sup.+.
[0380] (5,6-Dichloro-3-pyridyl)methanamine. A solution of 2-[(5,6-dichloro-3-pyridyl)methyl]isoindoline-1,3-dione (6.00 g, 19.5 mmol, 1.00 eq) and hydrazine hydrate (4.89 g, 97.7 mmol, 4.75 mL, 5.00 eq) in ethanol (60 mL) was heated to 70° C. for 3 hrs. The mixture was concentrated under reduced pressure to give a residue. The crude product was used in the next step without purification. (5,6-Dichloro-3-pyridyl)methanamine (3.00 g, crude) was obtained as a light yellow solid; m/z=177.2 (M+1)+.
[0381] N-[(5,6-Dichloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine. To a solution of (5,6-dichloro-3-pyridyl)methanamine (3.00 g, 16.5 mmol, 1.00 eq) and benzophenone (2.91 g, 16.5 mmol, 1.00 eq) in toluene (30 mL) was added p-toluenesulfonic acid (567 mg, 3.29 mmol, 0.200 eq). The mixture was stirred at 110° C. for 10 hrs. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (Silica gel, petroleum ether/ethyl acetate=100/1 to 20/1) to get the product (petroleum ether/ethyl acetate=5/1, Rf=0.6) (1.50 g, crude) as yellow oil; m/z=341.4 (M+1).sup.+.
[0382] 2,3-Dichloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. A solution of N-[(5,6-dichloro-3-pyridyl)methyl]-1,1-diphenyl-methanimine (1.36 g, 4.00 mmol, 1.00 eq) in tetrahydrofuran (10 mL) was added lithium diisopropylamide (2 M, 4 mL, 2.00 eq) at −70° C. and stirred for 30 min. Then cis-1,4-dichloro-2-butene (500 mg, 4.00 mmol, 420 uL, 1.00 eq) was added to the mixture. The mixture was warmed to 25° C. and stirred for 8 hrs. The mixture was quenched with HCl (1 M) (50 mL) and stirred for 0.5 h. Then adjust pH to 12 with NaOH solution (40%) and extracted with dichloromethane (20 mL×3). The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by reversed phase (HCl condition, ISCO®; 40 g SepaFlash® Silica Flash Column, eluent of 0˜20% acetonitrile/Water, flow rate 40 mL/min) to get 2,3-dichloro-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (108.21 mg, 357 umol, 8.93% yield, 99.7% purity) as a light yellow solid; m/z=229.1 (M+1).sup.+; 1H NMR (400 MHz, MeOD) 8.49-8.48 (d, J=2.4, 1H), 8.19-8.18 (d, J=2.0, 1H), 6.12-5.90 (m, 2H), 4.67-4.63 (m, 1H), 4.01-3.80 (m, 2H), 2.75-2.68 (m, 2H).
##STR00071## ##STR00072##
[0383] 2-[(5-Bromo-3-pyridyl)methyl]isoindoline-1,3-dione. To a solution of (5-bromo-3-pyridyl)methanol (10.0 g, 53.2 mmol, 1.00 eq) and phthalimide (7.83 g, 53.2 mmol, 1.00 eq), PPh3 (20.9 g, 79.8 mmol, 1.50 eq) in tetrahydrofuran (100 mL) was added diethyl azodicarboxylate (13.9 g, 79.8 mmol, 14.5 mL, 1.50 eq) at 0° C. The mixture was stirred at 25° C. for 10 hrs. The mixture was poured into water (200 mL) and then extracted with ethyl acetate (200 mL×3). The combined organic layers were washed with brine (500 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=50/1 to 5/1) to get 2-[(5-bromo-3-pyridyl)methyl]isoindoline-1,3-dione (14.0 g, 43.7 mmol, 82.2% yield, 99% purity) as a yellow solid, m/z=317.0 (M+1).sup.+.
[0384] (5-Bromo-3-pyridyl)methanamine. A mixture of 2-[(5-bromo-3-pyridyl)methyl]isoindoline-1,3-dione (13.0 g, 40.9 mmol, 1.00 eq) and hydrazine hydrate (10.3 g, 205 mmol, 9.96 mL, 5.00 eq) in EtOH (100 mL) was heated at 70° C. for 3 hrs. The mixture was concentrated under reduced pressure to give a residue. The crude product was used in the next step without purification. (5-Bromo-3-pyridyl)methanamine (10.0 g, crude) was obtained as a yellow solid, m/z=189.2 (M+1).sup.+.
[0385] N-[(5-Bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine. To a solution of (5-bromo-3-pyridyl)methanamine (10.0 g, 54.9 mmol, 1.00 eq) and benzophenone (10.3 g, 54.9 mmol, 1.00 eq) in toluene (100 mL) was added p-toluenesulfonic acid (1.89 g, 11.0 mmol, 0.20 eq). The mixture was stirred at 110° C. for 10 hrs. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=100/1 to 10/1) to get N-[(5-bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine (15.0 g, crude) as yellow oil.
[0386] 3-Bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. A solution of N-[(5-bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine (14.1 g, 40.0 mmol, 1.00 eq) in tetrahydrofuran (50 mL) was added lithium diisopropylamide (2 M, 40 mL, 2.00 eq) at −70° C. and stirred for 30 mins. Then cis-1,4-dichloro-2-butene (5.00 g, 40.0 mmol, 4.2 mL, 1.00 eq) was added to the mixture. The mixture was warmed to 25° C. for 8 hrs. The mixture was quenched with HCl (1 M) (100 mL) and stirred for 0.5 h. Then adjust pH to 12 with NaOH solution (40%) and extracted with dichloromethane (50 mL×3). The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by reversed phase (basic condition, ISCO®; 40 g SepaFlash® Silica Flash Column, Eluent of 0˜20% acetonitrile/water, flow rate 40 mL/min) to get 3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (1.10 g, 4.57 mmol, 11.4% yield, 99.4% purity) as yellow oil, m/z=239.2 (M+1).sup.+.
[0387] N-tert-Butyloxycarbonyl-3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of 3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (1.10 g, 4.57 mmol, 1.00 eq) and 4-(dimethylamino)pyridine (56 mg, 457 umol, 0.100 eq) in dichloromethane (10 mL) was added triethylamine (1.39 g, 13.7 mmol, 1.91 mL, 3.00 eq) and di-tert-butyl dicarbonate (998 mg, 4.57 mmol, 1.05 mL, 1.00 eq). The mixture was stirred at 25° C. for 10 hrs. The mixture was washed with brine (30 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20/1 to 10/1) to get the product (1.10 g, 3.15 mmol, 68.9% yield, 97.2% purity) as a light yellow oil, m/z=339.2 (M+1).sup.+.
[0388] tert-Butyl 2-[5-(2-trimethylsilylethynyl)-3-pyridyl]-3,6-dihydro-2H-pyridine-1-carboxylate. To a solution of N-tert-butyloxycarbonyl-3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (300 mg, 884 umol, 1.00 eq), CuI (17 mg, 88.4 umol, 0.100 eq), Pd(PPh.sub.3).sub.2Cl.sub.2 (62 mg, 88.4 umol, 0.10 eq) in N,N-dimethylformamide (10 mL) was added triethylamine (358 mg, 3.54 mmol, 492 uL, 4.00 eq). Then ethynyl(trimethyl)silane (104 mg, 1.06 mmol, 147 uL, 1.20 eq) was added to the mixture and the mixture was stirred at 25° C. for 3 hrs. The mixture was poured into water (30 mL) and extracted with ethyl acetate (15 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to get a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20/1) to obtain tert-butyl 2-[5-(2-trimethylsilylethynyl)-3-pyridyl]-3,6-dihydro-2H-pyridine-1-carboxylate (300 mg, crude) as a brown oil, m/z=357.4 (M+1).sup.+.
[0389] tert-Butyl 2-(5-ethynyl-3-pyridyl)-3,6-dihydro-2H-pyridine-1-carboxylate. To a solution of tert-butyl 2-[5-(2-trimethylsilylethynyl)-3-pyridyl]-3,6-dihydro-2H-pyridine-1-carboxylate (300 mg, 841 umol, 1.00 eq) in methanol (3 mL) and dichloromethane (6 mL) was added K.sub.2CO.sub.3 (348 mg, 2.52 mmol, 2.99 eq). The mixture was stirred at 25° C. for 2 hrs. The reaction mixture was concentrated under reduced pressure to remove solvent. Then the residue was diluted with water (10 mL) and extracted with dichloromethane (10 mL×2). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative TLC (SiO2, petroleum ether/ethyl acetate=2/1) to get the product (Rf=0.60) (140 mg, 492 umol, 58.5% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.58-8.51 (m, 2H), 7.68 (s, 1H), 5.92-5.89 (m, 2H), 5.71-5.54 (m, 1H), 4.26-4.22 (m, 1H), 3.36-3.32 (m, 1H), 3.21 (s, 1H), 2.77-2.47 (m, 2H), 1.49 (s, 9H).
[0390] 2-(5-ethynyl-3-pyridyl)-3,6-dihydro-2H-pyridine. To a solution of tert-butyl 2-(5-ethynyl-3-pyridyl)-3,6-dihydro-2H-pyridine-1-carboxylate (140 mg, 492 umol, 1.00 eq) in ethyl acetate (5 mL) was added solution of hydrogen chloride in ethyl acetate (4 M, 3 mL, 24.4 eq). The mixture was stirred at 25° C. for 2 hrs. The mixture was concentrated under reduced pressure to give a residue. The residue was stirred in ethyl acetate (20 mL) for 0.5 hr, filtered and the solid was collected to get target 2-(5-ethynyl-3-pyridyl)-3,6-dihydro-2H-pyridine dihydrochloride (77.64 mg, 282 umol, 57.3% yield, 93.4% purity) as a brown solid; m/z=185.3 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 9.01-8.88 (m, 2H), 8.58 (s, 1H), 6.13-5.92 (m, 2H), 4.82-4.77 (m, 1H), 4.32 (s, 1H), 4.25-4.03 (m, 1H), 4.00-3.99 (m, 1H), 2.86-2.73 (m, 2H)
##STR00073##
[0391] 2-[(5-Bromo-3-pyridyl)methyl]isoindoline-1,3-dione. To a solution of (5-bromo-3-pyridyl)methanol (10.0 g, 53.2 mmol, 1.00 eq) and phthalimide (7.83 g, 53.2 mmol, 1.00 eq), PPh3 (20.9 g, 79.8 mmol, 1.50 eq) in tetrahydrofuran (100 mL) was added diethyl azodicarboxylate (13.9 g, 79.8 mmol, 14.5 mL, 1.50 eq) at 0° C. The mixture was stirred at 25° C. for 10 hrs. The mixture was poured into water (200 mL) and then extracted with ethyl acetate (200 mL×3). The combined organic layers were washed with brine (500 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=50/1 to 5/1) to get 2-[(5-bromo-3-pyridyl)methyl]isoindoline-1,3-dione (14.0 g, 43.7 mmol, 82.2% yield, 99% purity) as a yellow solid, m/z=317.0 (M+1).sup.+.
[0392] (5-Bromo-3-pyridyl)methanamine. A mixture of 2-[(5-bromo-3-pyridyl)methyl]isoindoline-1,3-dione (13.0 g, 40.9 mmol, 1.00 eq) and hydrazine hydrate (10.3 g, 205 mmol, 9.96 mL, 5.00 eq) in EtOH (100 mL) was heated at 70° C. for 3 hrs. The mixture was concentrated under reduced pressure to give a residue. The crude product was used in the next step without purification. (5-Bromo-3-pyridyl)methanamine (10.0 g, crude) was obtained as a yellow solid, m/z=189.2 (M+1).sup.+.
[0393] N-[(5-Bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine. To a solution of (5-bromo-3-pyridyl)methanamine (10.0 g, 54.9 mmol, 1.00 eq) and benzophenone (10.3 g, 54.9 mmol, 1.00 eq) in toluene (100 mL) was added p-toluenesulfonic acid (1.89 g, 11.0 mmol, 0.20 eq). The mixture was stirred at 110° C. for 10 hrs. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=100/1 to 10/1) to get N-[(5-bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine (15.0 g, crude) as yellow oil.
[0394] 3-Bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. A solution of N-[(5-bromo-3-pyridyl)methyl]-1,1-diphenyl-methanimine (14.1 g, 40.0 mmol, 1.00 eq) in tetrahydrofuran (50 mL) was added lithium diisopropylamide (2 M, 40 mL, 2.00 eq) at −70° C. and stirred for 30 mins. Then cis-1,4-dichloro-2-butene (5.00 g, 40.0 mmol, 4.2 mL, 1.00 eq) was added to the mixture. The mixture was warmed to 25° C. for 8 hrs. The mixture was quenched with HCl (1 M) (100 mL) and stirred for 0.5 h. Then adjust pH to 12 with NaOH solution (40%) and extracted with dichloromethane (50 mL×3). The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by reversed phase (basic condition, ISCO®; 40 g SepaFlash® Silica Flash Column, Eluent of 0˜20% acetonitrile/water, flow rate 40 mL/min) to get 3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (1.10 g, 4.57 mmol, 11.4% yield, 99.4% purity) as yellow oil, m/z=239.2 (M+1).sup.+.
[0395] N-tert-Butyloxycarbonyl-3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine. To a solution of 3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (1.10 g, 4.57 mmol, 1.00 eq) and 4-(dimethylamino)pyridine (56 mg, 457 umol, 0.100 eq) in dichloromethane (10 mL) was added triethylamine (1.39 g, 13.7 mmol, 1.91 mL, 3.00 eq) and di-tert-butyl dicarbonate (998 mg, 4.57 mmol, 1.05 mL, 1.00 eq). The mixture was stirred at 25° C. for 10 hrs. The mixture was washed with brine (30 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20/1 to 10/1) to get the product (1.10 g, 3.15 mmol, 68.9% yield, 97.2% purity) as a light yellow oil, m/z=339.2 (M+1).sup.+.
[0396] tert-Butyl 5-[5-(1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridin-2-yl)-3-pyridyl]-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate. To a solution of N-tert-butyloxycarbonyl-3-bromo-5-(1,2,3,6-tetrahydropyridin-2-yl)pyridine (200 mg, 589 umol, 1.00 eq) in toluene (10 mL) was added tert-butyl 2,5-diazabicyclo[2.2′0.1]heptane-2-carboxylate (117 mg, 590 umol, 1.0 eq), t-BuONa (85 mg, 884 umol, 1.50 eq), tris(dibenzylideneacetone)dipalladium(0) (54 mg, 58.9 umol, 0.100 eq) and Xantphos (34 mg, 58.9 umol, 0.1 eq). The mixture was stirred at 100° C. for 3 hrs under N.sub.2. The mixture was poured into water (30 mL) and extracted with ethyl acetate (15 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to get a residue. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20/1 to 5/1) to get the product (petroleum ether/ethyl acetate=5/1, Rf=0.25), 120 mg, 244 umol, 41.5% yield, 93.0% as yellow oil; m/z=457.4 (M+1).sup.+.
[0397] 2-[5-(1,2,3,6-Tetrahydropyridin-2-yl)-3-pyridyl]-2,5-diazabicyclo[2.2.1]heptane. To a solution of tert-butyl 5-[5-(1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridin-2-yl)-3-pyridyl]-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate (120 mg, 263 umol, 1.00 eq) in ethyl acetate (5 mL) was added solution of hydrogen chloride in ethyl acetate (4 M, 3.00 mL, 45.6 eq). The mixture was stirred at 25° C. for 1 hr. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (HCl condition; column: Phenomenex Synergi C18 150*25*10 um; mobile phase: [water (0.05% HCl)-acetonitrile]; B %: 0%-10%, 5 min) to obtain 2-[5-(1,2,3,6-tetrahydropyridin-2-yl)-3-pyridyl]-2,5-diazabicyclo[2.2.1]heptane dihydrochloride (48.94 mg, 130 umol, 49.6% yield, 97.4% purity) as a yellow gum; m/z=257.0 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 8.35-8.25 (m, 2H), 8.21-8.18 (m, 1H), 6.13-5.91 (m, 2H), 5.02 (s, 1H), 4.77-4.67 (m, 2H), 4.02-3.84 (m, 4H), 3.77-3.45 (m, 2H), 2.89-2.68 (m, 2H), 2.38-2.19 (m, 2H).
##STR00074##
[0398] N-(p-Tolylmethyl)-1-(3-pyridyl)methanimine. To a solution of pyridine-3-carbaldehyde (13.7 g, 100 mmol, 12.9 mL, 1.00 eq) in 2-propanol (250 mL), p-methoxybenzylamine (16.1 g, 150 mmol, 14.1 mL, 1.50 eq) and acetic acid (1.50 g, 25.0 mmol, 1.43 mL, 0.25 eq) were added. The reaction mixture was stirred at 25° C. for 1.5 hrs. The reaction mixture was concentrated and then diluted with ethyl acetate (150 mL). The resulting solution was washed with saturated NaHCO.sub.3 solution (50 mL×2) and brine (50 mL×2), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (28.1 g, crude) was obtained as a brown oil and used into the next step without further purification.
[0399] 1-(p-Tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one. To a solution of N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (19.5 g, 86.2 mmol, 1.00 eq) in dry tetrahydrofuran (450 mL) was added a solution of ZnCl.sub.2 (12.9 g, 94.8 mmol, 4.44 mL, 1.10 eq) in tetrahydrofuran (50 mL) and dichloromethane (50 mL) at −78° C. and stirred for 10 mins. Then 1-methoxy-3-[(trimethylsilyl)oxy]-1,3-butadiene (18.6 g, 108 mmol, 21.0 mL, 1.25 eq) was added to the mixture, and after stirring for 30 mins the mixture was allowed to warm up to −20° C. and stirred for 20 mins. Then the reaction mixture was allowed to warm to 25° C. and stirred for 12 hrs. The reaction mixture was quenched with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was acidified with 1 M HCl (400 mL). The resulting aqueous phase was separated and further washed with ethyl acetate (400 mL). Then the aqueous phase was neutralized with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0˜80% ethyl acetate/petroleum ether gradient, flow rate 100 mL/min) to obtain 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (13.4 g, 45.4 mmol, 52.6% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.59-8.45 (m, 2H), 7.66-7.63 (m, 1H), 7.27-7.05 (m, 2H), 7.05-7.03 (m, 2H), 6.89-6.87 (m, 2H), 5.11-5.09 (m, 1H), 4.53-4.49 (m, 1H), 4.36-4.31 (m, 1H), 4.09-3.81 (m, 1H), 3.80 (s, 3H), 2.91-2.85 (m, 1H), 2.63-2.56 (m, 1H).
[0400] [1-(p-Tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate. To a solution of 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (11.0 g, 37.4 mmol, 1.00 eq) and N,N-bis(trifluoromethylsulfonyl)aniline (14.7 g, 41.1 mmol, 1.10 eq) in tetrahydrofuran (50 mL), L-selectride (1 M, 41.1 mL, 1.10 eq) was added dropwise at −78° C. After 1 h, the solution was allowed to warm up to 25° C. and stirred for another hour. The reaction mixture was quenched with saturated NH.sub.4Cl solution (500 mL) and extracted with ethyl acetate (300 mL×2). The combined organic phase was washed with brine (500 mL), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated to obtain a brown residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=30/1 to 3/1) to get [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]trifluoromethanesulfonate (Petroleum ether/Ethyl acetate=3/1, Rf=0.6) (5.20 g, 12.1 mmol, 32.5% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.65-8.57 (m, 2H), 7.79-7.77 (m, 1H), 7.36-7.33 (m, 1H), 7.27-7.18 (m, 2H), 6.87-6.84 (m, 2H), 6.01-5.55 (m, 1H), 3.94-3.91 (m, 1H), 3.80 (s, 3H), 3.62-3.58 (m, 1H), 3.26-3.17 (m, 1H), 3.14-3.06 (m, 2H), 2.73-2.71 (m, 2H).
[0401] 3-[4-Phenyl-1-(p-tolylmethyl)-3,6-dihydro-2H-pyridin-2-yl]pyridine. To a solution of [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate (500 mg, 1.17 mmol, 1.00 eq), phenylboronic acid (427 mg, 3.50 mmol, 3.00 eq) in dioxane (10 mL) and H.sub.2O (2 mL) was added K.sub.2CO.sub.3 (484 mg, 3.50 mmol, 700 uL, 3.00 eq) and bis(triphenylphosphine)palladium(II) dichloride (85 mg, 116 umol, 0.100 eq). The mixture was stirred at 80° C. for 2 hrs. The mixture was poured into water (30 mL) and then extracted with Ethyl acetate (15 mL×2). The combined organic layers were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=20/1 to 5/1) to yield 3-[4-phenyl-1-(p-tolylmethyl)-3,6-dihydro-2H-pyridin-2-yl]pyridine (Petroleum ether/Ethyl acetate=1/1, Rf=0.4) (0.400 g, crude) as a yellow solid; m/z=357.4 (M+1).sup.+.
[0402] 3-(4-phenyl-1,2,3,6-tetrahydropyridin-2-yl)pyridine. 3-[4-Phenyl-1-(p-tolylmethyl)-3,6-dihydro-2H-pyridin-2-yl]pyridine (400 mg, 1.12 mmol, 1.00 eq) and trifluoroacetic acid (7.70 g, 67.5 mmol, 5 mL, 60.2 eq) were taken up into a microwave tube. The sealed tube was heated at 100° C. for 2 hrs under microwave. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by reverse phase (0.1% HCl) to yield 3-(4-phenyl-1,2,3,6-tetrahydropyridin-2-yl)pyridine dihydrochloride (94.15 mg); m/z=237.1 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) 9.24-9.16 (m, 1H), 9.03.-9.01 (m, 1H), 8.97-8.95 (m, 1H), 8.29-8.26 (m, 1H), 7.60-7.54 (m, 2H), 7.43-7.38 (m, 3H), 6.31-6.29 (m, 1H), 5.72-5.71 (m, 0.4H), 5.09-5.05 (m, 0.6H), 4.19-4.11 (m, 1H), 3.62-3.61 (m, 1H), 3.28-2.99 (m, 2H).
##STR00075##
[0403] N-(p-Tolylmethyl)-1-(3-pyridyl)methanimine. To a solution of pyridine-3-carbaldehyde (13.7 g, 100 mmol, 12.9 mL, 1.00 eq) in 2-propanol (250 mL), p-methoxybenzylamine (16.1 g, 150 mmol, 14.1 mL, 1.50 eq) and acetic acid (1.50 g, 25.0 mmol, 1.43 mL, 0.25 eq) were added. The reaction mixture was stirred at 25° C. for 1.5 hs. The reaction mixture was concentrated and then diluted with ethyl acetate (150 mL). The resulting solution was washed with saturated NaHCO.sub.3 solution (50 mL×2) and brine (50 mL×2), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (28.1 g, crude) was obtained as a brown oil and used into the next step without further purification.
[0404] 1-(p-Tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one. To a solution of N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (19.5 g, 86.2 mmol, 1.00 eq) in dry tetrahydrofuran (450 mL) was added a solution of ZnCl.sub.2 (12.9 g, 94.8 mmol, 4.44 mL, 1.10 eq) in tetrahydrofuran (50 mL) and dichloromethane (50 mL) at −78° C. and stirred for 10 mins. Then 1-methoxy-3-[(trimethylsilyl)oxy]-1,3-butadiene (18.6 g, 108 mmol, 21.0 mL, 1.25 eq) was added to the mixture, and after stirring for 30 mins the mixture was allowed to warm up to −20° C. and stirred for 20 mins. Then the reaction mixture was allowed to warm to 25° C. and stirred for 12 hrs. The reaction mixture was quenched with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was acidified with 1 M HCl (400 mL). The resulting aqueous phase was separated and further washed with ethyl acetate (400 mL). Then the aqueous phase was neutralized with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0˜80% ethyl acetate/petroleum ether gradient, flow rate 100 mL/min) to obtain 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (13.4 g, 45.4 mmol, 52.6% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.59-8.45 (m, 2H), 7.66-7.63 (m, 1H), 7.27-7.05 (m, 2H), 7.05-7.03 (m, 2H), 6.89-6.87 (m, 2H), 5.11-5.09 (m, 1H), 4.53-4.49 (m, 1H), 4.36-4.31 (m, 1H), 4.09-3.81 (m, 1H), 3.80 (s, 3H), 2.91-2.85 (m, 1H), 2.63-2.56 (m, 1H).
[0405] [1-(p-Tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate. To a solution of 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (11.0 g, 37.4 mmol, 1.00 eq) and N,N-bis(trifluoromethylsulfonyl)aniline (14.7 g, 41.1 mmol, 1.10 eq) in tetrahydrofuran (50 mL), L-selectride (1 M, 41.1 mL, 1.10 eq) was added dropwise at −78° C. After 1 h, the solution was allowed to warm up to 25° C. and stirred for another hour. The reaction mixture was quenched with saturated NH.sub.4Cl solution (500 mL) and extracted with ethyl acetate (300 mL×2). The combined organic phase was washed with brine (500 mL), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated to obtain a brown residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=30/1 to 3/1) to get [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]trifluoromethanesulfonate (Petroleum ether/Ethyl acetate=3/1, Rf=0.6) (5.20 g, 12.1 mmol, 32.5% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.65-8.57 (m, 2H), 7.79-7.77 (m, 1H), 7.36-7.33 (m, 1H), 7.27-7.18 (m, 2H), 6.87-6.84 (m, 2H), 6.01-5.55 (m, 1H), 3.94-3.91 (m, 1H), 3.80 (s, 3H), 3.62-3.58 (m, 1H), 3.26-3.17 (m, 1H), 3.14-3.06 (m, 2H), 2.73-2.71 (m, 2H).
[0406] 3-[1-(p-Tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]pyridine. To a solution of [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate (500 mg, 1.17 mmol, 1.00 eq) and 3-pyridinylboronic acid (430 mg, 3.50 mmol, 3.00 eq) in water (2 mL) and dioxane (8 mL) was added K.sub.2CO.sub.3 (2 M, 1.75 mL, 3.00 eq) and bis(triphenylphosphine)palladium(II) dichloride (85 mg, 117 umol, 0.100 eq). The mixture was stirred at 80° C. for 2 hrs. The mixture was poured into water (30 mL) and then extracted with ethyl acetate (15 mL×2). The combined organic layers were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=10/1 to 2/1) to yield 3-[1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]pyridine (TLC: Petroleum ether/Ethyl acetate=0/1, Rf=0.3) (0.330 g, crude) as a yellow oil; m/z=358.3 (M+1).sup.+.
[0407] 3-[2-(3-Pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine. 3-[1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]pyridine (0.330 g, 923 umol, 1.00 eq) and trifluoroacetic acid (7.70 g, 67.5 mmol, 5 mL, 73.2 eq) were taken up into a microwave tube. The sealed tube was heated at 100° C. for 2 hrs under microwave. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by reverse phase (0.1% HCl) to yield 3-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine dihydrochloride (177 mg, 555 umol, 60.1% yield, 97.2% purity) as a light yellow solid; m/z=238.2 (M+1).sup.+; .sup.1H NMR (400 MHz, DMSO-d.sub.6) 11.03 (s, 1H), 10.49 (s, 1H), 9.17-9.06 (m, 1H), 9.06-8.91 (m, 1H), 8.90-8.84 (m, 1H), 8.82-8.76 (m, 1H), 8.76-8.65 (m, 1H), 8.65-8.50 (m, 1H), 8.03-7.99 (m, 2H), 6.75 (s, 1H), 4.86 (s, 1H), 4.10-3.97 (m, 2H), 3.30-3.23 (m, 1H), 3.14-3.09 (m, 1H).
##STR00076##
[0408] Diethyl (pyridin-3-ylmethylene)dicarbamate. To a solution of nicotinaldehyde (10.0 g 93.4 mmol, 8.77 mL, 1.00 eq) and ethyl carbamate (18.3 g, 205 mmol, 2.20 eq) in toluene (20.0 mL) was added p-toluenesulfonic acid (804 mg, 4.67 mmol, 0.05 eq). The mixture was stirred at 120° C. for 12 hrs. The reaction mixture was cooled to 0° C. The residue was filtered and washed with toluene (100 mL×3) to yield diethyl (pyridin-3-ylmethylene)dicarbamate (10.0 g, 37.4 mmol, 40.1% yield) as a white solid; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.67-8.66 (m, 1H), 8.54-8.52 (m, 1H), 7.76-7.73 (m, 1H), 7.30-7.28 (m, 1H), 6.21 (s, 3H), 4.17-4.11 (m, 4H), 1.27-1.23 (m, 6H).
[0409] Ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of diethyl (pyridin-3-ylmethylene)dicarbamate (8.00 g, 29.9 mmol, 1.00 eq) in chloroform (40.0 mL) was added boron trifluoride diethyl etherate (21.2 g, 149 mmol, 18.5 mL, 5.00 eq) and cyclohexa-1,3-diene (4.80 g, 59.9 mmol, 5.70 mL, 2.00 eq). The mixture was stirred at 70° C. for 3 hrs. The reaction mixture was quenched by addition saturated solution of NaHCO.sub.3 (100 mL) at 25° C., and then diluted with water (100 mL) and extracted with dichloromethane (100 mL×3). The combined organic layers were washed with water (100 mL×2) and brine (100 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (10.0 g, crude) as a yellow oil; m/z=259 (M+1).sup.+. 2-Methyl-3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of lithium aluminum hydride (2.35 g, 61.9 mmol, 8.00 eq) in dry tetrahydrofuran (25.0 mL) at 0° C., ethyl 3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (2.00 g, 7.74 mmol, 1.00 eq) in tetrahydrofuran (25.0 mL) was added. The mixture was stirred at 25° C. for 10 hrs. The reaction mixture was quenched with water (2.00 mL), 15% NaOH (aq, 2.00 mL) and water (6.00 mL). Then the reaction mixture was dried over Na.sub.2SO.sub.4, filtered and the filtrate was concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (neutral condition; column: Phenomenex Gemini 150*25 mm*10 um; mobile phase: [water (0.04% NH.sub.4OH+10 mM NH.sub.4HCO.sub.3)—acetonitrile]; B %: 40%-67%, 10 min) to yield 2-methyl-3-(pyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (12.9 mg, 63.4 μmol, 0.819% yield, 97.9% purity) as a yellow oil; m/z=201 (M+1).sup.+; .sup.1H NMR (400 MHz, MeOD) δ 8.65 (m, 1H), 8.40 (m, 1H), 8.02-7.93 (m, 1H), 7.47-7.35 (m, 1H), 6.62-6.57 (m, 1H), 6.43-6.32 (m, 1H), 3.49-3.41 (m, 1H), 3.12-3.05 (m, 1H), 2.53-2.44 (m, 1H), 2.17 (s, 3H), 2.06-1.94 (m, 1H), 1.39-1.19 (m, 2H), 0.95-0.86 (m, 1H).
##STR00077##
[0410] Diethyl (6-chloropyridin-3-ylmethylene)dicarbamate. To a solution of 6-chloropyridine-3-carbaldehyde (10.0 g, 70.7 mmol, 1.00 eq) and ethyl carbamate (14.0 g, 157 mmol, 2.22 eq) in toluene (50.0 mL) was added p-toluenesulfonic acid (608 mg, 3.53 mmol, 0.05 eq). The mixture was stirred at 120° C. for 24 hrs. The reaction mixture was cooled to 0° C. The residue was filtered and the solid was collected. Diethyl (6-chloropyridin-3-ylmethylene)dicarbamate (20.0 g, crude) was white solid; m/z=302 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.45-8.44 (m, 1H), 7.73-7.70 (m, 1H), 7.33-7.31 (m, 1H), 6.18-6.14 (m, 1H), 6.05-6.04 (m, 1H), 4.19-4.12 (m, 4H), 1.28-1.24 (m, 6H).
[0411] Ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of diethyl (6-chloropyridin-3-ylmethylene)dicarbamate (10.0 g, 33.1 mmol, 1.00 eq) in chloroform (50.0 mL) was added boron trifluoride diethyl etherate (23.5 g, 165 mmol, 20.5 mL, 5.00 eq) and cyclohexa-1,3-diene (5.31 g, 66.3 mmol, 6.31 mL, 2.00 eq). The mixture was stirred at 70° C. for 12 hrs. The reaction mixture was quenched by addition saturated solution of NaHCO.sub.3 (100 ml) at 25° C., and then diluted with water (100 mL) and extracted with dichloromethane (100 mL×3). The combined organic layers were washed with brine (100 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to yield ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (9.00 g, crude) as a yellow oil; m/z=293 (M+1).sup.+.
[0412] 3-(6-Ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (7.00 g, 23.9 mmol, 1.00 eq) in ethanol (60.0 mL) was added NaOH (12.0 g, 300 mmol, 12.6 eq). The reaction mixture was stirred at 90° C. for 12 hrs. The reaction mixture was concentrated under reduced pressure. Then the residue was adjusted to pH=1 (1 M HCl), then the mixture was extracted with ethyl acetate (50.0 mL×2). The combined aqueous layers were adjusted to pH=10 (NaOH), then the mixture was extracted with ethyl acetate (50.0 mL×2), dried over sodium sulfate, filtered and concentrated under reduced pressure to give a residue. 3-(6-Ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (2.00 g, 8.68 mmol, 36.3% yield) was obtained as a yellow oil; m/z=231 (M+1).sup.+.
[0413] 2-Methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of 3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (2.00 g, 8.68 mmol, 1.00 eq) in formic acid (10.0 mL) was added formaldehyde (6.54 g, 80.6 mmol, 6.00 mL, 37.0% purity, 9.28 eq). The mixture was stirred at 100° C. for 2 hrs. The mixture was quenched with a 40 percent (w/v) solution of NaOH (pH=9) and extracted with dichloromethane (20.0 mL×2). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.10% NH.sub.4OH mobile phase). 2-Methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (500 mg, 2.05 mmol, 23.5% yield) was obtained as a yellow oil; m/z=245 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.16-8.13 (m, 1H), 7.74-7.68 (m, 1H), 6.74-6.68 (m, 1H), 6.59-6.53 (m, 1H), 6.32-6.26 (m, 1H), 4.26-4.21 (m, 2H), 3.41-3.39 (m, 1H), 2.39-2.34 (m, 1H), 2.13 (s, 3H), 1.99-1.90 (m, 1H), 1.36-1.28 (m, 5H), 0.93-0.81 (m, 1H).
[0414] 2-Methyl-3-(6-hydroxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. Solution of 2-methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene 8 (260 mg, 1.06 mmol, 1.00 eq) in hydrochloric acid (3 M, 5.00 mL, 14.1 eq) was stirred at 100° C. for 12 hrs. The reaction mixture was concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.10% HCl condition). 2-Methyl-3-(6-hydroxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (100 mg, 462 μmol, 43.5% yield) was obtained as a yellow oil; m/z=217 (M+1).sup.+.
[0415] 2-Methyl-3-(6-chloroxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. Solution of 2-methyl-3-(6-hydroxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene 9 (100 mg, 462 umol, 1.00 eq) in POCl.sub.3 (8.27 g, 53.9 mmol, 5.01 mL, 116 eq) was stirred at 70° C. for 12 hrs. The reaction mixture was poured into the water (10.0 mL), then the mixture was adjusted to pH=10 and extracted with dichloromethane (20.0 mL×2). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (basic condition; column: Waters Xbridge 150*25 5u; mobile phase: [water (0.05% ammonia hydroxide v/v)—ACN]; B %: 48%-78%, 10 min). 2-Methyl-3-(6-chloroxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (17.6 mg, 73.7 umol, 15.9% yield, 98.2% purity) was obtained as a yellow solid; m/z=235 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.46-8.53 (m, 1H), 7.83-7.79 (m, 1H), 7.31-7.27 (m, 1H), 6.59-6.53 (m, 1H), 6.37-6.32 (m, 1H), 3.44-3.38 (m, 1H), 3.02-2.98 (m, 1H), 2.46-2.41 (m, 1H), 2.16 (s, 3H), 2.01-1.92 (m, 1H), 1.36-1.21 (m, 2H), 0.96-0.86 (m, 2H).
##STR00078##
[0416] Diethyl (6-chloropyridin-3-ylmethylene)dicarbamate. To a solution of 6-chloropyridine-3-carbaldehyde (10.0 g, 70.7 mmol, 1.00 eq) and ethyl carbamate (14.0 g, 157 mmol, 2.22 eq) in toluene (50.0 mL) was added p-toluenesulfonic acid (608 mg, 3.53 mmol, 0.05 eq). The mixture was stirred at 120° C. for 24 hrs. The reaction mixture was cooled to 0° C. The residue was filtered and the solid was collected. Diethyl (6-chloropyridin-3-ylmethylene)dicarbamate (20.0 g, crude) was white solid; m/z=302 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.45-8.44 (m, 1H), 7.73-7.70 (m, 1H), 7.33-7.31 (m, 1H), 6.18-6.14 (m, 1H), 6.05-6.04 (m, 1H), 4.19-4.12 (m, 4H), 1.28-1.24 (m, 6H).
[0417] Ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of diethyl (6-chloropyridin-3-ylmethylene)dicarbamate (10.0 g, 33.1 mmol, 1.00 eq) in chloroform (50.0 mL) was added boron trifluoride diethyl etherate (23.5 g, 165 mmol, 20.5 mL, 5.00 eq) and cyclohexa-1,3-diene (5.31 g, 66.3 mmol, 6.31 mL, 2.00 eq). The mixture was stirred at 70° C. for 12 hrs. The reaction mixture was quenched by addition saturated solution of NaHCO.sub.3 (100 ml) at 25° C., and then diluted with water (100 mL) and extracted with dichloromethane (100 mL×3). The combined organic layers were washed with brine (100 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to yield ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (9.00 g, crude) as a yellow oil; m/z=293 (M+1).sup.+.
[0418] 3-(6-Ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of ethyl 3-(6-chloropyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (7.00 g, 23.9 mmol, 1.00 eq) in ethanol (60.0 mL) was added NaOH (12.0 g, 300 mmol, 12.6 eq). The reaction mixture was stirred at 90° C. for 12 hrs. The reaction mixture was concentrated under reduced pressure.
[0419] Then the residue was adjusted to pH=1 (1 M HCl), then the mixture was extracted with ethyl acetate (50.0 mL×2). The combined aqueous layers were adjusted to pH=10 (NaOH), then the mixture was extracted with ethyl acetate (50.0 mL×2), dried over sodium sulfate, filtered and concentrated under reduced pressure to give a residue. 3-(6-Ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (2.00 g, 8.68 mmol, 36.3% yield) was obtained as a yellow oil; m/z=231 (M+1).sup.+.
[0420] 2-Methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of 3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (2.00 g, 8.68 mmol, 1.00 eq) in formic acid (10.0 mL) was added formaldehyde (6.54 g, 80.6 mmol, 6.00 mL, 37.0% purity, 9.28 eq). The mixture was stirred at 100° C. for 2 hrs. The mixture was quenched with a 40 percent (w/v) solution of NaOH (pH=9) and extracted with dichloromethane (20.0 mL×2). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.10% NH.sub.4OH mobile phase). 2-Methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (500 mg, 2.05 mmol, 23.5% yield) was obtained as a yellow oil; m/z=245 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.16-8.13 (m, 1H), 7.74-7.68 (m, 1H), 6.74-6.68 (m, 1H), 6.59-6.53 (m, 1H), 6.32-6.26 (m, 1H), 4.26-4.21 (m, 2H), 3.41-3.39 (m, 1H), 2.39-2.34 (m, 1H), 2.13 (s, 3H), 1.99-1.90 (m, 1H), 1.36-1.28 (m, 5H), 0.93-0.81 (m, 1H).
[0421] 3-(6-Ethoxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane. To a solution of 2-methyl-3-(6-ethoxypyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (250 mg, 1.02 mmol, 1.00 eq) in ethanol (5.00 mL) was added Pd/C (100 mg, 1.02 mmol, 10.0%, 1.00 eq) under N.sub.2. The suspension was degassed under vacuum and purged with H.sub.2 several times. The mixture was stirred under H.sub.2 (15 psi) at 25° C. for 10 hrs. The mixture was filtered and concentrated under reduced pressure to give a residue. 3-(6-Ethoxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane (150 mg, 608 umol, 59.5% yield) was obtained as colorless oil; m/z=247 (M+1).sup.+.
[0422] 3-(6-Hydroxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane. Solution of 3-(6-ethoxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane (250 mg, 1.01 mmol, 1.00 eq) in hydrochloric acid (3 M, 25.0 mL, 73.9 eq) was stirred at 100° C. for 24 hrs. The reaction mixture was concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.10% HCl condition). 3-(6-Hydroxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane hydrochloride (230 mg, 902 umol, 88.9% yield) was obtained as a white solid; m/z=219 (M+1).sup.+.
[0423] 3-(6-Chloro-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane. Solution of 3-(6-hydroxy-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane hydrochloride (230 mg, 1.05 mmol, 1.00 eq) in POCl.sub.3 (8.10 g, 52.8 mmol, 4.91 mL, 50.1 eq) was stirred at 70° C. for 12 hrs. The reaction mixture was poured into the water (10.0 mL), then pH of the solution was adjusted to 10 (NaHCO.sub.3, aq) and extracted with dichloromethane (20.0 mL×2). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (basic condition; column: Xtimate C18 150*25 mm*5 um; mobile phase: [water (0.05% ammonium hydroxide v/v) —acetonitrile]; B %: 60%-90%, 10 min) to 3-(6-chloro-3-pyridyl)-2-methyl-2-azabicyclo[2.2.2]octane (87.9 mg, 369 umol, 35.1% yield, 99.4% purity) was obtained as an off-white solid; m/z=237 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.41-8.38 (m, 1H), 7.54-7.51 (m, 1H), 7.26-7.23 (m, 1H), 3.38-3.35 (m, 1H), 2.63-2.59 (m, 1H), 2.44 (s, 3H), 2.09-1.99 (m, 1H), 1.94-1.75 (m, 2H), 1.69-1.61 (m, 1H), 1.56-1.31 (m, 4H), 1.24-1.19 (m, 1H).
##STR00079##
[0424] 6-Phenylpyridine-3-carbaldehyde. To a solution of 6-bromopyridine-3-carbaldehyde (24.5 g, 132 mmol, 1.00 eq), phenylboronic acid (24.1 g, 198 mmol, 1.50 eq) in toluene (70.0 mL) and ethanol (70.0 mL) was added solution of Na.sub.2CO.sub.3 (2 M, 35.0 mL, 5.31e-1.00 eq), then Pd(PPh.sub.3).sub.4 (15.2 g, 13.1 mmol, 0.10 eq) was added under N.sub.2. The mixture was stirred at 80° C. for 3 hrs. The reaction mixture was quenched by addition of water (200 mL), and extracted with ethyl acetate (150 mL×3). The combined organic layers were washed with aqueous NaCl (100 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=1:0 to 5:1). TLC (Petroleum ether/Ethyl acetate=5/1, Rf of P1 was 0.50). 6-Phenylpyridine-3-carbaldehyde (18.0 g, 94.4 mmol, 71.7% yield, 96.1% purity) was obtained as a light yellow solid; m/z=184 (M+1).sup.+.
[0425] Diethyl (6-phenylpyridin-3-ylmethylene)dicarbamate. To a solution of 6-phenylpyridine-3-carbaldehyde (18.0 g, 98.3 mmol, 1.00 eq) in toluene (200 mL) was added p-toluenesulfonic acid (845 mg, 4.91 mmol, 0.05 eq) and ethyl carbamate (21.9 g, 245 mmol, 2.50 eq). The mixture was stirred at 120° C. for 12 hrs. The reaction mixture was cooled to 0° C. and filtered. The crude product was triturated with toluene (50.0 mL) at 25° C. for 30 min. Diethyl (6-phenylpyridin-3-ylmethylene)dicarbamate (25.0 g, 72.8 mmol, 74.1% yield) was obtained as a white solid; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.81-8.74 (m, 1H), 8.03-7.93 (m, 2H), 7.86-7.78 (m, 1H), 7.71-7.62 (m, 1H), 7.52-7.38 (m, 3H), 6.32-6.16 (m, 1H), 6.11-5.76 (m, 2H), 4.22-4.09 (m, 4H), 1.35-1.20 (m, 6H).
[0426] 3-(6-Phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of diethyl (6-phenylpyridin-3-ylmethylene)dicarbamate (5.00 g, 14.5 mmol, 1.00 eq) in chloroform (50.0 mL) was added cyclohexa-1,3-diene (2.33 g, 29.1 mmol, 2.77 mL, 2.00 eq) and trifluoride diethyl etherate (10.3 g, 72.8 mmol, 8.99 mL, 5.00 eq). The mixture was stirred at 70° C. for 10 hrs. The mixture was quenched with saturated solution of NaHCO.sub.3 (100 mL) and extracted with dichloromethane (50.0 mL×2). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated to get the residue. 3-(6-Phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (4.00 g, crude) was obtained as a yellow oil; m/z=335 (M+1).sup.+.
[0427] 3-(6-Phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene. 3-(6-Phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (1.00 g, 2.99 mmol, 1.00 eq) was dissolved in a 20 percent (w/v) solution of NaOH (10.0 g, 250 mmol, 83.6 eq) in absolute ethanol (50.0 mL) and the mixture was stirred at 100° C. for 12 hrs. The reaction mixture was concentrated under reduced pressure. Then the residue was washed with water (50.0 mL) and extracted with ethyl acetate (50.0 mL×2). The combined organic layers were adjusted to pH=2 (1 M HCl), then the mixture was extracted with ethyl acetate (50.0 mL×2). The combined aqueous layers were adjusted to pH=10 (NaHCO.sub.3), then the mixture was extracted with ethyl acetate (50.0 mL×2), dried over sodium sulfate, filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (neutral condition; column: Waters Xbridge 150*25 5u; mobile phase: [water (10 mM NH.sub.4HCO.sub.3) —ACN]; B %: 35%-65%, 10 min) to yield 3-(6-phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (51.4 mg, 191 umol, 6.41% yield, 97.8% purity) as an off-white solid; m/z=263 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.81-8.76 (m, 1H), 8.05-7.95 (m, 3H), 7.76-7.69 (m, 1H), 7.51-7.48 (m, 3H), 6.64-6.57 (m, 1H), 6.51-6.44 (m, 1H), 3.97-3.87 (m, 1H), 3.74-3.64 (m, 1H), 2.66-2.55 (m, 1H), 2.07-1.93 (m, 1H), 1.44-1.24 (m, 3H), 1.04-0.93 (m, 1H).
[0428] 3-(6-Phenyl-3-pyridyl)-2-azabicyclo[2.2.2]octane. To a solution of 3-(6-phenylpyridin-3-yl)-2-azabicyclo[2.2.2]oct-5-ene (300 mg, 1.14 mmol, 1.00 eq) in ethanol (10.0 mL) was added Pd/C (100 mg, 1.14 mmol, 10.0%, 1.00 eq) under N.sub.2. The suspension was degassed under vacuum and purged with H.sub.2 several times. The mixture was stirred under H.sub.2 (15 psi) at 25° C. for 10 hrs. The mixture was filtered and then the filtrate was concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (basic condition, column: Xtimate C18 150*25 mm*5 um; mobile phase: [water (0.05% ammonium hydroxide v/v)—acetonitrile]; B %: 47%-77%). 3-(6-Phenyl-3-pyridyl)-2-azabicyclo[2.2.2]octane (250 mg, 945 μmol, 82.7% yield, 100% purity) was obtained as an off-white solid; m/z=265 (M+1).sup.+; 1H NMR (400 MHz, CDCl.sub.3) δ 8.76-8.71 (m, 1H), 8.04-7.47 (m, 3H), 7.76-7.63 (m, 1H), 7.51-7.39 (m, 3H), 4.41-4.32 (m, 1H), 3.07-2.96 (m, 1H), 2.07-1.72 (m, 7H), 1.54-1.23 (m, 3H).
[0429] 2-Methyl-3-(6-phenyl-3-pyridyl)-2-azabicyclo[2.2.2]octane. To a solution of 3-(6-phenyl-3-pyridyl)-2-azabicyclo[2.2.2]octane (170 mg, 643 μmol, 1.00 eq) in formic acid (5.00 mL) was added formaldehyde (545 mg, 6.72 mmol, 0.50 mL, 37.0% purity, 10.4 eq). The mixture was stirred at 100° C. for 10 hrs. The mixture was quenched with a 40 percent (w/v) solution of NaOH (pH=9) and extracted with dichloromethane (20.0 mL×2). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (HCl condition, column: Phenomenex Synergi C18 150*25*10 um; mobile phase: [water (0.05% HCl)—acetonitrile]; B %: 8%-28%, 9 min). 2-Methyl-3-(6-phenyl-3-pyridyl)-2-azabicyclo[2.2.2]octane (87.5 mg, 276 μmol, 42.9% yield, 99.3% purity, HCl) was obtained as an off-white solid; m/z=279 (M+1).sup.+; 1H NMR (400 MHz, MeOD) δ 9.26-9.18 (m, 1H), 9.03-8.92 (m, 1H), 8.54-8.49 (m, 1H), 8.06-7.97 (m, 2H), 7.79-7.66 (m, 3H), 3.66-3.62 (m, 1H), 3.04 (s, 3H), 2.66-2.52 (m, 1H), 2.46-2.34 (m, 1H), 2.24-1.81 (m, 8H).
##STR00080##
[0430] tert-Butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate. To a solution of 3-iodopyridine (682 mg, 3.33 mmol, 1.50 eq) in tetrahydrofuran (5 mL) was added n-BuLi (2.50 M, 1.33 mL, 1.50 eq) at −78° C. The mixture was stirred at −78° C. for 0.5 hr. Then tert-butyl 5-oxo-2-azabicyclo[2.2.2]octane-2-carboxylate (0.500 g, 2.22 mmol, 1.00 eq) in tetrahydrofuran (5 mL) was added. The mixture was stirred at −78° C. for 2 hrs. The reaction mixture was quenched by addition of saturated aqueous solution of NH.sub.4Cl (3 mL) at −78° C., and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=10/1 to 1/1). tert-Butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (0.224 g, 736 umol, 33.2% yield) was obtained as an yellow oil; m/z=305 (M+1).sup.+.
[0431] tert-Butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of tert-butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (224 mg, 736 umol, 1.00 eq) in dichloromethane (10 mL) was added triethylamine (744 mg, 7.36 mmol, 1.02 mL, 10.0 eq) and methanesulfonyl chloride (421 mg, 3.68 mmol, 284 μL, 5.00 eq) at 0° C. The mixture was stirred at 25° C. for 2 hrs. The reaction mixture was quenched by addition water 2 mL at 0° C. and then concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% NH.sub.4OH). tert-Butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.150 g, 523 umol, 71.2% yield) was obtained as an yellow oil; m/z=287 (M+1).sup.+.
[0432] 5-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of tert-butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.150 g, 523 umol, 1.00 eq) in dioxane (5 mL) was added HCl/dioxane (4 M, 131 uL, 1 eq). The mixture was stirred at 25° C. for 0.5 hr. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by prep-TLC (SiO2, DCM/MeOH=10/1). TLC (Dichloromethane/Methanol=10/1) showed one major spot (Rf=0.35) was detected. 5-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (11.7 mg, 62.6 umol, 11.9% yield, 99.7% purity) was obtained as an yellow solid; m/z=205 (M+19).sup.+; .sup.1H NMR (400 MHz, MeOD) δ 8.72 (s, 1H), 8.48 (m, 1H), 8.00 (m, 1H), 7.46 (m, 1H), 6.85 (m, 1H), 4.15 (m, 1H), 3.41 (s, 1H), 3.22-3.18 (m, 1H), 2.80-2.70 (m, 1H), 2.19-2.13 (m, 1H), 1.94-1.89 (m, 1H), 1.60-1.49 (m, 2H).
##STR00081##
[0433] tert-Butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate. To a solution of 3-iodopyridine (682 mg, 3.33 mmol, 1.50 eq) in tetrahydrofuran (5 mL) was added n-BuLi (2.50 M, 1.33 mL, 1.50 eq) at −78° C. The mixture was stirred at −78° C. for 0.5 hr. Then tert-butyl 5-oxo-2-azabicyclo[2.2.2]octane-2-carboxylate (0.500 g, 2.22 mmol, 1.00 eq) in tetrahydrofuran (5 mL) was added. The mixture was stirred at −78° C. for 2 hrs. The reaction mixture was quenched by addition of saturated aqueous solution of NH.sub.4Cl (3 mL) at −78° C., and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=10/1 to 1/1). tert-Butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (0.224 g, 736 umol, 33.2% yield) was obtained as an yellow oil; m/z=305 (M+1).sup.+.
[0434] tert-Butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of tert-butyl 5-hydroxy-5-(3-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (224 mg, 736 umol, 1.00 eq) in dichloromethane (10 mL) was added triethylamine (744 mg, 7.36 mmol, 1.02 mL, 10.0 eq) and methanesulfonyl chloride (421 mg, 3.68 mmol, 284 μL, 5.00 eq) at 0° C. The mixture was stirred at 25° C. for 2 hrs. The reaction mixture was quenched by addition water 2 mL at 0° C. and then concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% NH.sub.4OH). tert-Butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.150 g, 523 umol, 71.2% yield) was obtained as an yellow oil; m/z=287 (M+1).sup.+.
[0435] 5-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of tert-butyl 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.150 g, 523 umol, 1.00 eq) in dioxane (5 mL) was added HCl/dioxane (4 M, 131 uL, 1 eq). The mixture was stirred at 25° C. for 0.5 hr. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by prep-TLC (SiO2, DCM/MeOH=10/1). TLC (Dichloromethane/Methanol=10/1) showed one major spot (Rf=0.35) was detected. 5-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (11.7 mg, 62.6 umol, 11.9% yield, 99.7% purity) was obtained as an yellow solid; m/z=205 (M+19).sup.+; .sup.1H NMR (400 MHz, MeOD) δ 8.72 (s, 1H), 8.48 (m, 1H), 8.00 (m, 1H), 7.46 (m, 1H), 6.85 (m, 1H), 4.15 (m, 1H), 3.41 (s, 1H), 3.22-3.18 (m, 1H), 2.80-2.70 (m, 1H), 2.19-2.13 (m, 1H), 1.94-1.89 (m, 1H), 1.60-1.49 (m, 2H).
[0436] 2-Methyl-5-(3-pyridyl)-2-azabicyclo[2.2.2]ocit-5-ene. To a solution of 5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene in formic acid (5 mL) was added formaldehyde (545 mg, 6.72 mmol, 0.5 mL, 37.0% purity, 17.8 eq). The mixture was stirred at 100° C. for 2 hrs. The mixture was quenched with a 40 percent (w/v) solution of NaOH (pH=9) and extracted with dichloromethane (20 mL×2). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by prep-TLC (SiO2, DCM/MeOH=10/1). TLC (DCM/MeOH=10/1) showed one major spot (Rf=0.25) was detected. 2-Methyl-5-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (24.0 mg, 118 μmol, 31.5% yield, 98.7% purity) was obtained as a brown gum; m/z=201 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.73 (m, 1H), 8.57 (m, 1H), 7.78-7.73 (m, 1H), 7.35-7.32 (m, 1H), 6.73-6.67 (m, 1H), 4.28 (m, 1H), 4.07-3.99 (m, 1H), 3.67 (m, 1H), 3.31 (m, 1H), 2.58 (s, 3H), 2.36-2.32 (m, 1H), 1.95-1.91 (m, 1H), 1.54-1.42 (m, 2H).
##STR00082##
[0437] tert-Butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate. To the solution of 2-chloro-5-iodopyridine (1.28 g, 5.33 mmol, 1.20 eq) in tetrahydrofuran (15.0 mL) was added n-BuLi (2.50 M, 2.2 mL, 1.24 eq) drop-wise at −60° C. The mixture was stirred at −60° C. for 0.5 hr. Then the solution of tert-butyl 5-oxo-2-azabicyclo[2.2.2]octane-2-carboxylate (1.00 g, 4.44 mmol, 1.00 eq) in tetrahydrofuran (15.0 mL) was added drop-wise. The resulting mixture was stirred at −60° C. for 1.5 hr. The reaction mixture was quenched by saturated solution of NH.sub.4Cl (30 mL), diluted with water (50 mL) and extracted with ethyl acetate (30 mL×3). The combined organic phases were washed with brine (60 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuum. The residue was purified by column chromatography (SiO.sub.2, Petroleum ether/Ethyl acetate=5:1 to 2:1) to obtain tert-butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (750 mg, 2.05 mmol, 46.3% yield, 92.8% purity) as a yellow oil; m/z=339.1 (M+H).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.57-8.46 (m, 1H), 7.88-7.67 (m, 1H), 7.37-7.29 (m, 1H), 4.37-4.17 (m, 1H), 3.31-3.11 (m, 1H), 3.01-2.92 (m, 1H), 2.79-2.61 (m, 1H), 2.50-2.30 (m, 2H), 2.27-2.20 (m, 1H), 2.18-2.06 (m, 1H), 1.92-1.82 (m, 2H), 1.63-1.57 (m, 1H).
[0438] tert-Butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To the solution of tert-butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (500 mg, 1.48 mmol, 1.00 eq) and triethylamine (900 mg, 8.89 mmol, 1.24 mL, 6.03 eq) in dichloromethane (10.0 mL) was added methanesulfonyl chloride (845 mg, 7.38 mmol, 570 μL, 5.00 eq) at 0° C. Then the mixture was stirred at 30° C. for 2 hr. The reaction mixture was diluted with water (30 mL), extracted with dichloromethane (15 mL×2). The combined organic phases were washed with brine (30 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuum. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=10/1 to 5/1), the spot (Rf=0.8) to obtain tert-butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (363 mg, 1.06 mmol, 71.6% yield, 93.4% purity) as a colorless oil; m/z=321.1 (M+H).sup.+.
[0439] 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2. To the solution of tert-butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (363 mg, 1.13 mmol, 1.00 eq) in ethyl acetate (8.00 mL) was added HCl/ethyl acetate (4.00 M, 6.13 mL, 21.7 eq). Then the mixture was stirred at 30° C. for 1 hr. The reaction mixture was concentrated under vacuum to yield 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2 hydrochloride (310 mg, crude) as a light yellow oil; m/z=192.1 (M−28).sup.+; .sup.1H NMR (400 MHz, METHANOL-d4) δ 8.57 (d, J=2.4 Hz, 1H), 8.60-8.54 (m, 1H), 8.04-7.98 (m, 1H), 7.53-7.48 (m, 1H), 6.83 (dd, J=2.0, 6.0 Hz, 1H), 4.50-4.39 (m, 1H), 3.53 (br d, J=2.4 Hz, 1H), 3.34 (s, 1H), 2.91 (br d, J=11.6 Hz, 1H), 2.24-2.14 (m, 1H), 2.01-1.91 (m, 1H), 1.70-1.53 (m, 2H).
##STR00083##
[0440] tert-Butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate. To the solution of 2-chloro-5-iodopyridine (1.28 g, 5.33 mmol, 1.20 eq) in tetrahydrofuran (15.0 mL) was added n-BuLi (2.50 M, 2.2 mL, 1.24 eq) drop-wise at −60° C. The mixture was stirred at −60° C. for 0.5 hr. Then the solution of tert-butyl 5-oxo-2-azabicyclo[2.2.2]octane-2-carboxylate (1.00 g, 4.44 mmol, 1.00 eq) in tetrahydrofuran (15.0 mL) was added drop-wise. The resulting mixture was stirred at −60° C. for 1.5 hr. The reaction mixture was quenched by saturated solution of NH.sub.4Cl (30 mL), diluted with water (50 mL) and extracted with ethyl acetate (30 mL×3). The combined organic phases were washed with brine (60 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuum. The residue was purified by column chromatography (SiO.sub.2, Petroleum ether/Ethyl acetate=5:1 to 2:1) to obtain tert-butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (750 mg, 2.05 mmol, 46.3% yield, 92.8% purity) as a yellow oil; m/z=339.1 (M+H).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.57-8.46 (m, 1H), 7.88-7.67 (m, 1H), 7.37-7.29 (m, 1H), 4.37-4.17 (m, 1H), 3.31-3.11 (m, 1H), 3.01-2.92 (m, 1H), 2.79-2.61 (m, 1H), 2.50-2.30 (m, 2H), 2.27-2.20 (m, 1H), 2.18-2.06 (m, 1H), 1.92-1.82 (m, 2H), 1.63-1.57 (m, 1H).
[0441] tert-Butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To the solution of tert-butyl 5-hydroxy-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]octane-2-carboxylate (500 mg, 1.48 mmol, 1.00 eq) and triethylamine (900 mg, 8.89 mmol, 1.24 mL, 6.03 eq) in dichloromethane (10.0 mL) was added methanesulfonyl chloride (845 mg, 7.38 mmol, 570 μL, 5.00 eq) at 0° C. Then the mixture was stirred at 30° C. for 2 hr. The reaction mixture was diluted with water (30 mL), extracted with dichloromethane (15 mL×2). The combined organic phases were washed with brine (30 mL), dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuum. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=10/1 to 5/1), the spot (Rf=0.8) to obtain tert-butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (363 mg, 1.06 mmol, 71.6% yield, 93.4% purity) as a colorless oil; m/z=321.1 (M+H).sup.+.
[0442] 5-(2-Chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2. To the solution of tert-butyl 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (363 mg, 1.13 mmol, 1.00 eq) in ethyl acetate (8.00 mL) was added HCl/ethyl acetate (4.00 M, 6.13 mL, 21.7 eq). Then the mixture was stirred at 30° C. for 1 hr. The reaction mixture was concentrated under vacuum to yield 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2 hydrochloride (310 mg, crude) as a light yellow oil; m/z=192.1 (M−28).sup.+; .sup.1H NMR (400 MHz, METHANOL-d4) δ 8.57 (d, J=2.4 Hz, 1H), 8.60-8.54 (m, 1H), 8.04-7.98 (m, 1H), 7.53-7.48 (m, 1H), 6.83 (dd, J=2.0, 6.0 Hz, 1H), 4.50-4.39 (m, 1H), 3.53 (br d, J=2.4 Hz, 1H), 3.34 (s, 1H), 2.91 (br d, J=11.6 Hz, 1H), 2.24-2.14 (m, 1H), 2.01-1.91 (m, 1H), 1.70-1.53 (m, 2H).
[0443] 2-Methyl-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2. The solution of 5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2 hydrochloride (210 mg, 951.53 umol, 1 eq) and formaldehyde (1.64 g, 20.1 mmol, 1.50 mL, 21.2 eq) in formic acid (4.00 mL) was stirred at 95-100° C. for 10 hr. The reaction mixture was diluted with water (10 mL), adjusted pH to 8 with sat. NaHCO.sub.3, extracted with ethyl acetate (20 mL×4). The combined organic phases were dried over MgSO.sub.4, filtered and concentrated under vacuum to obtain 2-methyl-5-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2 (20 mg, 72.43 umol, 7.61% yield, 85% purity) as a light yellow oil; m/z=235.1 (M+H).sup.+; 1H NMR (400 MHz, METHANOL-d4) δ 8.58 (d, J=2.0 Hz, 1H), 8.01 (dd, J=2.4, 8.4 Hz, 1H), 7.50 (d, J=8.8 Hz, 1H), 6.83 (d, J=6.0 Hz, 1H), 4.56 (s, 2H), 3.51-3.37 (m, 2H), 2.72 (s, 3H), 2.22 (br d, J=7.2 Hz, 1H), 1.93-1.84 (m, 1H), 1.70-1.53 (m, 2H).
##STR00084## [0444] 3-Vinylpyridine. A mixture of 3-iodopyridine (16.0 g, 78.1 mmol, 1.00 eq), potassium trifluoro(vinyl)borate (14.6 g, 109 mmol, 1.40 eq), triethylamine (23.7 g, 234 mmol, 32.6 mL, 3.00 eq), bis(triphenylphosphine)palladium(II) dichloride (2.86 g, 3.90 mmol, 0.05 eq) and water (50.0 g, 2.77 mol, 50 mL, 35.5 eq) in 2-propanol (160 mL) was degassed and purged with N.sub.2 for 3 times, and then the mixture was stirred at 80° C. for 3 hrs under N.sub.2 atmosphere. The reaction mixture was diluted with water (100 mL) and extracted with ethyl acetate (50 mL×3). The organic layer was washed with brine (50 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated to give the residue. The product was purified by chromatography on a silica gel eluted with petroleum ether:ethyl acetate (from 100:1 to 2:1, petroleum ether/ethyl acetate=5/1, product Rf=0.4) to give a yellow liquid. 3-Vinylpyridine (3.91 g, 36.8 mmol, 47.2% yield, 99.1% purity) was obtained as a yellow liquid; .sup.1H NMR (400 MHz, CDCl3) δ 8.62 (d, 1H), 8.48 (dd, 1H), 7.73 (dt, 1H), 7.23-7.27 (m, 1H), 6.71 (dd, 1H), 5.83 (d, 1H), 5.38 (d, 1H).
[0445] Ethyl 2H-pyridine-1-carboxylate. To a solution of pyridine (10.0 g, 126 mmol, 10.2 mL, 1.00 eq) in methanol (200 mL) was added NaBH4 (6.00 g, 158 mmol, 1.25 eq) at −78° C. Then ethyl chloroformate (13.0 g, 120 mmol, 11.4 mL, 0.952 eq) was added dropwise at −78° C. The mixture was stirred at −78° C. for 1 hr. The reaction mixture was quenched by addition of water (100 mL) at 0° C., and then diluted with water (100 mL) and extracted with ethyl acetate (200 mL×3). The combined organic layers were washed with brine (150 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0˜20% Ethyl acetate/Petroleum ether gradient @ 100 mL/min). Ethyl 2H-pyridine-1-carboxylate (10.0 g, 65.3 mmol, 511.6% yield) was obtained as an yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 6.84-6.67 (m, 1H), 5.86-5.82 (m, 1H), 5.53-5.52 (m, 1H), 5.13-5.11 (m, 1H), 4.38-4.36 (m, 2H), 4.24-4.20 (m, 2H), 1.32-1.30 (m, 3H).
[0446] Ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of ethyl 2H-pyridine-1-carboxylate (0.800 g, 5.22 mmol, 2.00 eq) in decalin (5 mL) was added 3-vinylpyridine (274 mg, 2.61 mmol, 1.00 eq). The mixture was stirred at 250° C. for 1 hr under microwave irradiation. The reaction mixture was concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% NH.sub.4OH). Ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (100 mg, 387 μmol, 7.41% yield) was obtained as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.65-8.43 (m, 2H), 7.57-7.42 (m, 1H), 7.22-7.15 (m, 1H), 6.63-6.57 (m, 1H), 6.32-6.26 (m, 1H), 4.82-4.79 (m, 1H), 4.26-4.11 (m, 2H), 3.47-3.43 (m, 2H), 3.38-3.35 (m, 1H), 2.92 (s, 1H), 2.22-2.16 (m, 2H), 1.30-1.24 (m, 3H).
[0447] 7-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.100 g, 387 umol, 1.00 eq) in ethanol (10 mL) was added NaOH (774 mg, 19.3 mmol, 50.0 eq). The mixture was stirred at 100° C. for 3 hrs. NaOH (619.35 mg, 15.48 mmol, 40.0 eq) was added, the mixture was stirred at 100° C. for 12 hrs. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% NH.sub.4OH). 7-(3-Pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (39.0 mg, 182 umol, 47.1% yield, 87.0% purity) was obtained as a yellow solid; m/z=187 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.48-8.45 (m, 1H), 8.43-8.41 (m, 1H), 7.47-7.44 (m, 1H), 7.18-7.15 (m, 1H), 6.56 (t, J=7.4 Hz, 1H), 6.37-6.34 (m, 1H), 3.53-3.52 (m, 1H), 3.52-3.51 (m, 1H), 3.02-2.99 (m, 1H), 2.79-2.77 (m, 1H), 2.51-2.49 (m, 1H), 2.21-2.12 (m, 1H), 1.51-1.44 (m, 2H).
##STR00085##
[0448] 7-(2-Chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene was obtained from 2-chloro-5-iodopyridine and ethyl 2H-pyridine-1-carboxylate according to procedures described for Compound 22; m/z=221 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.33-8.32 (m, 1H), 7.81-7.80 (m, 1H), 7.31-7.29 (m, 1H), 6.62-6.59 (m, 1H), 6.44-6.41 (m, 1H), 3.32-3.30 (m, 1H), 3.06-3.03 (m, 1H), 2.77-2.73 (m, 2H), 2.59-2.56 (m, 1H), 1.86-1.79 (m, 1H), 1.29-1.27 (m, 1H).
##STR00086## [0449] 2-Piperidylmethanol. To a solution of N-tert-butoxycarbonyl-2-piperidylmethanol (500 mg, 27.9 mmol, 1.00 eq) in dichloromethane (20 mL) was added solution of hydrogen chloride in dioxane (4 M, 13.9 mL, 2.00 eq), the mixture was stirred at 25° C. for 0.5 hr. The reaction was concentrated to give 2-piperidylmethanol hydrochloride (350 mg, 27.9 mmol, 100% yield) as a white solid.
[0450] 3-(2-Piperidylmethoxy)pyridine. To a solution of 2-piperidylmethanol hydrochloride (350 mg, 27.9 mmol, 1.00 eq, HCl) in dimethylsulfoxide (10 mL) was added t-BuOK (1.71 g, 139 mmol, 5.00 eq) and 3-fluoropyridine (443 mg, 41.8 mmol, 390 uL, 1.50 eq), the mixture was stirred at 100° C. for 8 hrs. The reaction was diluted with water (100 mL), K.sub.3PO.sub.4 (3.00 g) was added, extracted with ethyl acetate (100 mL×2), combined organic phase was dried over Na.sub.2SO.sub.4, concentrated to give a residue. The residue was purified by column chromatography (SiO2, MeOH/Ethyl acetate=0/1 to 1/1; TLC:MeOH/Ethyl acetate=1/0 P1: Rf=0.27) to give 3-(2-piperidylmethoxy)pyridine (200.53 mg, 20.8 mmol, 74.6% yield) as a yellow gum; m/z=193.2 (M+1).sup.+; .sup.1H NMR (400 MHz, DMSO-d.sub.6) 8.29-8.27 (m, 1H), 8.17-8.15 (m, 1H), 7.39-7.37 (m, 1H), 7.33-7.30 (m, 1H), 3.95-3.91 (m, 1H), 3.85-3.81 (m, 1H), 2.96-2.94 (m, 1H), 2.84-2.80 (m, 1H), 2.43-2.16 (m, 1H), 1.76-1.74 (m, 1H), 1.66-1.63 (m, 1H), 1.53-1.51 (m, 1H), 1.34-1.31 (m, 2H), 1.29-1.21 (m, 1H).
##STR00087##
[0451] Benzyl (2S)-1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridine-2-carboxylate. To a solution of (2S)-1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridine-2-carboxylic acid (500 mg, 2.20 mmol, 1.00 eq) in DMF (5 mL) was added NaHCO.sub.3 (400 mg, 4.76 mmol, 185 uL, 2.16 eq) and benzyl bromide (576 mg, 3.37 mmol, 400 uL, 1.53 eq). The mixture was stirred at 25° C. for 12 hrs. The reaction mixture was partitioned between water (100 mL) and ethyl acetate 80 (mL).
[0452] The organic phase was separated, washed with water 80 mL (40 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 12 g SepaFlash® Silica Flash Column, eluent of 0˜20% ethyl acetate/petroleum ether gradient, flow rate 60 mL/min), to obtain benzyl (2S)-1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridine-2-carboxylate (600 mg, 1.89 mmol, 85.9% yield) as a colorless oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 7.37-7.32 (m, 5H), 5.75-5.65 (m, 2H), 5.17-5.11 (m, 3H), 4.08-4.03 (m, 1H), 3.82-3.74 (m, 1H), 2.73-2.65 (m, 1H), 2.53-2.48 (m, 1H), 1.47-1.41 (m, 9H).
[0453] [(2S)-1-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridin-2-yl]methanol. To a solution of benzyl (2S)-1-tert-butoxycarbonyl-3,6-dihydro-2H-pyridine-2-carboxylate (600 mg, 1.89 mmol, 1.00 eq) in THE (5 mL) was added LiBH.sub.4 (250 mg, 11.5 mmol, 6.07 eq). The mixture was stirred at 25° C. for 2 hrs. The reaction mixture was quenched by addition of NH.sub.4Cl (20 mL) at 25° C., and then diluted with water (20 mL) and extracted with ethyl acetate (20 mL×3). The combined organic layers were washed with brine 930 mL0, dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 12 g SepaFlash® Silica Flash Column, eluent of 0˜30% ethyl acetate/petroleum ether gradient, flow rate 60 mL/min), (360 mg, 1.69 mmol, 89.3% yield) to obtain [(2S)-1-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridin-2-yl]methanol as a colorless oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 5.74-5.72 (m, 1H), 5.71-5.68 (m, 1H), 4.48 (s, 1H), 4.19 (s, 1H), 3.66-3.49 (m, 3H), 2.43-2.37 (m, 1H), 2.05-1.99 (m, 1H), 1.49 (s, 9H).
[0454] [(2S)-1,2,3,6-tetrahydropyridin-2-yl]methanol. To a solution of [(2S)-1-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridin-2-yl]methanol (300 mg, 1.41 mmol, 1.00 eq) in dichloromethane (10 mL) was added solution of hydrogen chloride in dioxane (4 M, 2 mL, 5.69 eq). The mixture was stirred at 25° C. for 0.5 hr. The mixture was concentrated to give [(2S)-1,2,3,6-tetrahydropyridin-2-yl]methanol hydrochloride (210 mg, 1.41 mmol, 100.00% yield) as a white solid that was used into the next step without further purification.
[0455] 3-[[(2S)-1,2,3,6-Tetrahydropyridin-2-yl]methoxy]pyridine. To a solution of [(2S)-1,2,3,6-tetrahydropyridin-2-yl]methanol hydrochloride (210 mg, 1.41 mmol, 1.00 eq) in dimethylsulfoxide (5 mL) was added t-BuOK (789 mg, 7.03 mmol, 5.00 eq) and 3-fluoropyridine (205 mg, 2.11 mmol, 180 uL, 1.50 eq). The mixture was stirred at 100° C. for 8 hrs. The mixture was purified by preparative HPLC (basic condition) to give 3-[[(2S)-1,2,3,6-tetrahydropyridin-2-yl]methoxy]pyridine (114.58 mg, 586 umol, 41.7% yield, 97.3% purity) as a yellow oil; m/z=191.2 (M+1).sup.+; .sup.1H NMR) 400 MHz, DMSO-d.sub.6) 8.30-8.17 (m, 1H), 8.16-8.15 (m, 1H), 7.41-7.39 (m, 1H), 7.33-7.31 (m, 1H), 5.72 (s, 2H), 4.03-3.99 (m, 1H), 3.94-3.89 (m, 1H), 3.29-3.21 (m, 2H), 3.05-3.04 (m, 1H), 2.04-2.01 (m, 1H), 1.89-1.85 (m, 1H).
##STR00088## ##STR00089##
[0456] 2-(5-Bromo-2-pyridyl)ethynyl-trimethyl-silane. A mixture of 2,5-dibromopyridine (5.00 g, 21.1 mmol, 1.00 eq), triethylamine (8.54 g, 84.4 mmol, 11.7 mL, 4.00 eq), CuI (200 mg, 1.06 mmol, 0.0500 eq), Pd(PPh.sub.3).sub.2Cl.sub.2 (740 mg, 1.06 mmol, 0.0500 eq) and dimethylformamide (25 mL) was stirred. Ethynyl(trimethyl)silane (2.49 g, 25.3 mmol, 3.51 mL, 1.20 eq) was added and the mixture was stirred at 25° C. for 2 hrs. The mixture was filtered and was added water (100 mL), extracted with ethyl acetate (50 mL×3), washed with brine (100 mL), dried by Na.sub.2SO.sub.4, filtered and concentrated on vacuum. The residue was purified by column chromatography (SiO2, Petroleum ether/Ethyl acetate=1/0 to 10/1). TLC (Petroleum ether/Ethyl acetate=10/1, Rf of P1 was 0.5). 2-(5-Bromo-2-pyridyl)ethynyl-trimethyl-silane (3.00 g, 10.8 mmol, 51.5% yield, 92.1% purity) was obtained as a light yellow oil; m/z=254 (M+1).sup.+.
[0457] [6-(2-Trimethylsilylethynyl)-3-pyridyl]boronic acid. A mixture of 2-(5-bromo-2-pyridyl)ethynyl-trimethyl-silane (3.00 g, 11.8 mmol, 1.00 eq), bis(pinacolato)diboron (3.60 g, 14.1 mmol, 1.20 eq), KOAc (3.47 g, 35.4 mmol, 3.00 eq), Pd(PPh.sub.3).sub.2Cl.sub.2 (431 mg, 590 umol, 0.0500 eq) and dioxane (30 mL) was degassed and stirred at 85° C. for 2 hrs. To the mixture was added water (100 mL), extracted with ethyl acetate (50 mL×3), washed with brine (100 mL), dried by Na.sub.2SO.sub.4, filtered and concentrated on vacuum. The residue was purified by preparative HPLC (HCl). [6-(2-Trimethylsilylethynyl)-3-pyridyl]boronic acid (1.40 g, 4.89 mmol, 41.4% yield, 76.6% purity) was obtained as a dark brown oil; m/z=220 (M+1).sup.+.
[0458] N-(p-Tolylmethyl)-1-(3-pyridyl)methanimine. To a solution of pyridine-3-carbaldehyde (13.7 g, 100 mmol, 12.9 mL, 1.00 eq) in 2-propanol (250 mL), p-methoxybenzylamine (16.1 g, 150 mmol, 14.1 mL, 1.50 eq) and acetic acid (1.50 g, 25.0 mmol, 1.43 mL, 0.25 eq) were added. The reaction mixture was stirred at 25° C. for 1.5 hs. The reaction mixture was concentrated and then diluted with ethyl acetate (150 mL). The resulting solution was washed with saturated NaHCO.sub.3 solution (50 mL×2) and brine (50 mL×2), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (28.1 g, crude) was obtained as a brown oil and used into the next step without further purification.
[0459] 1-(p-Tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one. To a solution of N-(p-tolylmethyl)-1-(3-pyridyl)methanimine (19.5 g, 86.2 mmol, 1.00 eq) in dry tetrahydrofuran (450 mL) was added a solution of ZnCl.sub.2 (12.9 g, 94.8 mmol, 4.44 mL, 1.10 eq) in tetrahydrofuran (50 mL) and dichloromethane (50 mL) at −78° C. and stirred for 10 mins. Then 1-methoxy-3-[(trimethylsilyl)oxy]-1,3-butadiene (18.6 g, 108 mmol, 21.0 mL, 1.25 eq) was added to the mixture, and after stirring for 30 mins the mixture was allowed to warm up to −20° C. and stirred for 20 mins. Then the reaction mixture was allowed to warm to 25° C. and stirred for 12 hrs. The reaction mixture was quenched with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was acidified with 1 M HCl (400 mL). The resulting aqueous phase was separated and further washed with ethyl acetate (400 mL). Then the aqueous phase was neutralized with saturated NaHCO.sub.3 (400 mL) and extracted with ethyl acetate (150 mL×2). The combined organic phase was dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0˜80% ethyl acetate/petroleum ether gradient, flow rate 100 mL/min) to obtain 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (13.4 g, 45.4 mmol, 52.6% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.59-8.45 (m, 2H), 7.66-7.63 (m, 1H), 7.27-7.05 (m, 2H), 7.05-7.03 (m, 2H), 6.89-6.87 (m, 2H), 5.11-5.09 (m, 1H), 4.53-4.49 (m, 1H), 4.36-4.31 (m, 1H), 4.09-3.81 (m, 1H), 3.80 (s, 3H), 2.91-2.85 (m, 1H), 2.63-2.56 (m, 1H).
[0460] [1-(p-Tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate. To a solution of 1-(p-tolylmethyl)-2-(3-pyridyl)-2,3-dihydropyridin-4-one (11.0 g, 37.4 mmol, 1.00 eq) and N,N-bis(trifluoromethylsulfonyl)aniline (14.7 g, 41.1 mmol, 1.10 eq) in tetrahydrofuran (50 mL), L-selectride (1 M, 41.1 mL, 1.10 eq) was added dropwise at −78° C. After 1 h, the solution was allowed to warm up to 25° C. and stirred for another hour. The reaction mixture was quenched with saturated NH.sub.4Cl solution (500 mL) and extracted with ethyl acetate (300 mL×2). The combined organic phase was washed with brine (500 mL), dried over anhydrous Na.sub.2SO.sub.4, filtered and concentrated to obtain a brown residue. The residue was purified by column chromatography (silica gel, Petroleum ether/Ethyl acetate=30/1 to 3/1) to get [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]trifluoromethanesulfonate (Petroleum ether/Ethyl acetate=3/1, Rf=0.6) (5.20 g, 12.1 mmol, 32.5% yield) as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.65-8.57 (m, 2H), 7.79-7.77 (m, 1H), 7.36-7.33 (m, 1H), 7.27-7.18 (m, 2H), 6.87-6.84 (m, 2H), 6.01-5.55 (m, 1H), 3.94-3.91 (m, 1H), 3.80 (s, 3H), 3.62-3.58 (m, 1H), 3.26-3.17 (m, 1H), 3.14-3.06 (m, 2H), 2.73-2.71 (m, 2H).
[0461] Trimethyl-[2-[5-[1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]-2-pyridyl]ethynyl]silane. A mixture of [1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl] trifluoromethanesulfonate (500 mg, 1.17 mmol, 1.00 eq), [6-(2-trimethylsilylethynyl)-3-pyridyl]boronic acid (400 mg, 1.40 mmol, 1.20 eq), LiCl (49 mg, 1.17 mmol, 23.9 uL, 1.00 eq), Pd(PPh.sub.3).sub.2Cl.sub.2 (170 mg, 233 umol, 0.200 eq), K.sub.3PO.sub.4 (2 M, 1.75 mL, 3.00 eq) and dioxane (10 mL) was degassed and stirred at 80° C. for 2 hrs. The mixture was filtered and to the solution was added water (10 mL), extracted with ethyl acetate (5 mL×3), washed with brine (10 mL), dried by Na.sub.2SO.sub.4, filtered and concentrated on vacuum. The residue was purified by preparative HPLC (HCl). Trimethyl-[2-[5-[1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]-2-pyridyl]ethynyl]silane (0.300 g, 552 umol, 47.3% yield, 83.5% purity) was obtained as a dark brown oil; m/z=454 (M+1).sup.+.
[0462] Trimethyl-[2-[5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]-2-pyridyl]ethynyl]silane. Trimethyl-[2-[5-[1-(p-tolylmethyl)-2-(3-pyridyl)-3,6-dihydro-2H-pyridin-4-yl]-2-pyridyl]ethynyl]silane (0.250 g, 551 umol, 1.00 eq) and trifluoroacetic acid (2 mL) were taken up into a microwave tube. The sealed tube was heated at 100° C. for 2 hrs under microwave. The reaction mixture was concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% TFA condition). Trimethyl-[2-[5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]-2-pyridyl]ethynyl]silane (0.120 g, 359 umol, 65.3% yield) was obtained as a dark brown oil; m/z=334 (M+1).sup.+.
[0463] 2-Ethynyl-5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine. To a solution of trimethyl-[2-[5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]-2-pyridyl]ethynyl]silane (0.100 g, 299 umol, 1.00 eq) in methanol (1 mL) and dichloromethane (3 mL) was added K.sub.2CO.sub.3 (124 mg, 899 umol, 3.00 eq). The mixture was stirred at 25° C. for 1 h. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (basic condition; column: Xtimate C18 150*25 mm*5 um; mobile phase: [water (0.05% ammonia hydroxide v/v)-ACN]; B %: 12%-42%, 10 min). 2-Ethynyl-5-[2-(3-pyridyl)-1,2,3,6-tetrahydropyridin-4-yl]pyridine (15.8 mg, 58.5 umol, 19.5% yield, 96.7% purity) was obtained as a yellow solid; m/z=262 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) 8.69-8.65 (m, 2H), 8.58-8.56 (m, 1H), 7.79-7.78 (m, 1H), 7.65-7.63 (m, 1H), 7.45-7.43 (m, 1H), 7.44-7.33 (m, 1H), 6.35-6.33 (m, 1H), 4.06-4.02 (m, 1H), 3.82-3.74 (m, 2H), 3.18 (s, 1H), 2.64-2.67 (m, 2H).
##STR00090##
[0464] 3-Vinylpyridine. A mixture of 3-iodopyridine (16.0 g, 78.1 mmol, 1.00 eq), potassium trifluoro(vinyl)borate (14.6 g, 109 mmol, 1.40 eq), triethylamine (23.7 g, 234 mmol, 32.6 mL, 3.00 eq), bis(triphenylphosphine)palladium(II) dichloride (2.86 g, 3.90 mmol, 0.05 eq) and water (50.0 g, 2.77 mol, 50 mL, 35.5 eq) in 2-propanol (160 mL) was degassed and purged with N.sub.2 for 3 times, and then the mixture was stirred at 80° C. for 3 hrs under N.sub.2 atmosphere. The reaction mixture was diluted with water (100 mL) and extracted with ethyl acetate (50 mL×3). The organic layer was washed with brine (50 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated to give the residue. The product was purified by chromatography on a silica gel eluted with petroleum ether:ethyl acetate (from 100:1 to 2:1, petroleum ether/ethyl acetate=5/1, product Rf=0.4) to give a yellow liquid. 3-Vinylpyridine (3.91 g, 36.8 mmol, 47.2% yield, 99.1% purity) was obtained as a yellow liquid; .sup.1H NMR (400 MHz, CDCl3) δ 8.62 (d, 1H), 8.48 (dd, 1H), 7.73 (dt, 1H), 7.23-7.27 (m, 1H), 6.71 (dd, 1H), 5.83 (d, 1H), 5.38 (d, 1H).
[0465] Ethyl 2H-pyridine-1-carboxylate. To a solution of pyridine (10.0 g, 126 mmol, 10.2 mL, 1.00 eq) in methanol (200 mL) was added NaBH4 (6.00 g, 158 mmol, 1.25 eq) at −78° C. Then ethyl chloroformate (13.0 g, 120 mmol, 11.4 mL, 0.952 eq) was added dropwise at −78° C. The mixture was stirred at −78° C. for 1 hr. The reaction mixture was quenched by addition of water (100 mL) at 0° C., and then diluted with water (100 mL) and extracted with ethyl acetate (200 mL×3). The combined organic layers were washed with brine (150 mL×2), dried over Na.sub.2SO.sub.4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0˜20% Ethyl acetate/Petroleum ether gradient @ 100 mL/min). Ethyl 2H-pyridine-1-carboxylate (10.0 g, 65.3 mmol, 51.6% yield) was obtained as an yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 6.84-6.67 (m, 1H), 5.86-5.82 (m, 1H), 5.53-5.52 (m, 1H), 5.13-5.11 (m, 1H), 4.38-4.36 (m, 2H), 4.24-4.20 (m, 2H), 1.32-1.30 (m, 3H).
[0466] Ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate. To a solution of ethyl 2H-pyridine-1-carboxylate (0.800 g, 5.22 mmol, 2.00 eq) in decalin (5 mL) was added 3-vinylpyridine (274 mg, 2.61 mmol, 1.00 eq). The mixture was stirred at 250° C. for 1 hr under microwave irradiation. The reaction mixture was concentrated under reduced pressure to give a residue. The crude product was purified by reversed-phase HPLC (0.1% NH.sub.4OH). Ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (100 mg, 387 μmol, 7.41% yield) was obtained as a yellow oil; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.65-8.43 (m, 2H), 7.57-7.42 (m, 1H), 7.22-7.15 (m, 1H), 6.63-6.57 (m, 1H), 6.32-6.26 (m, 1H), 4.82-4.79 (m, 1H), 4.26-4.11 (m, 2H), 3.47-3.43 (m, 2H), 3.38-3.35 (m, 1H), 2.92 (s, 1H), 2.22-2.16 (m, 2H), 1.30-1.24 (m, 3H).
[0467] 2-Methyl-7-(3-pyridyl)-2-azabicyclo[2.2.2]ocit-5-ene. To a solution of ethyl 7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene-2-carboxylate (0.100 g, 387 umol, 1.00 eq) in tetrahydrofuran (5 mL) was added lithium aluminum hydride (117 mg, 3.10 mmol, 8.00 eq) at 0° C. The mixture was stirred at 25° C. for 2 hrs. The reaction mixture was quenched by addition water 5 mL at 0° C. and then filtered and concentrated under reduced pressure to give a residue. The residue was purified by prep-TLC (SiO2, DCM/MeOH=10/1). TLC (DCM/MeOH=10/1) showed one major spot (Rf=0.3) was detected. 2-Methyl-7-(3-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (15.9 mg, 78.7 μmol, 20.3% yield, 98.7% purity) was obtained as a white solid; m/z=201 (M+1).sup.+; .sup.1H NMR: (400 MHz, MeOD) δ 8.45-8.42 (m, 2H), 7.71-7.68 (m, 1H), 7.41-7.38 (m, 1H), 6.93-6.89 (m, 1H), 6.30-6.27 (m, 1H), 4.00 (m, 1H), 3.69-3.65 (m, 1H), 3.42-3.39 (m, 1H), 3.04 (m, 1H), 2.67 (s, 3H), 2.53-2.50 (m, 1H), 2.30-2.27 (m, 1H), 1.68-1.64 (m, 1H).
##STR00091##
[0468] 2-Methyl-7-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene. To a solution of 7-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (0.100 g, 453 umol, 1.00 eq) in formic acid (3 mL) was added formaldehyde (327 mg, 4.03 mmol, 0.3 mL, 37.0% purity, 8.89 eq). The mixture was stirred at 100° C. for 1 hr. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (basic condition; column: Xtimate C18 150*25 mm*5 um; mobile phase: [water (0.05% ammonia hydroxide v/v)-acetonitrile]; B %: 32%-62%, 10 min). 2-Methyl-7-(2-chloro-5-pyridyl)-2-azabicyclo[2.2.2]oct-5-ene (10.0 mg, 40.3 umol, 8.9% yield, 94.5% purity) was obtained as an yellow oil; m/z=235 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 8.20 (s, 1H), 7.45-7.43 (m, 1H), 7.20-7.18 (m, 1H), 6.68-6.65 (m, 1H), 6.17-6.13 (m, 1H), 3.55-3.53 (m, 1H), 3.41 (d, J=2.6 Hz, 1H), 3.23-3.20 (m, 1H), 2.76-2.74 (m, 1H), 2.33-2.13 (m, 3H), 2.13-2.01 (m, 1H), 1.99-1.97 (m, 1H), 1.47-1.43 (m, 1H).
[0469] Compound 29 was isolated as a side product during synthesis of Compound 28, m/z=245 (M+1).sup.+; .sup.1H NMR (400 MHz, CDCl.sub.3) δ 7.95 (s, 1H), 7.43-7.36 (m, 1H), 6.68-6.64 (m, 1H), 6.61-6.59 (m, 1H), 6.19-6.14 (m, 1H), 4.33-4.28 (m, 2H), 3.58-3.56 (m, 1H), 3.45-3.44 (m, 1H), 3.29-3.27 (m, 1H), 2.76-2.75 (m, 1H), 2.37 (s, 3H), 2.16-2.12 (m, 1H), 2.03-1.99 (m, 1H), 1.47-1.43 (m, 1H), 1.39-1.35 (m, 3H).