Reaction Steps
4-[2-(4-Methoxy-phenylamino)-[1,2,4]triazolo[1,5-a]pyridin-8-yl]-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester was prepared from (8-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-yl)-(4-methoxy-phenyl)-amine (150.0 mg, 0.4700 mmol) and 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (160.0 mg, 0.5174 mmol) with Pd(dppf)Cl2 (0.035 g) as the catalyst in a manner analogous to Step 19e. The reaction product was isolated as a clear viscous oil. 1H NMR (400 MHz, CDCl3, δ, ppm): 8.30 (dd, J=6.6, 1.0 Hz, 1H), 7.52-7.47 (m, 2H), 7.33-7.29 (m, 1H), 7.25-7.20 (m, 1H), 6.94-6.89 (m, 2H), 6.84 (dd, J=7.3, 7.3 Hz, 1H), 6.63 (s, 1H), 4.23-4.19 (m, 2H), 3.81 (s, 3H), 3.73-3.67 (m, 2H), 2.69-2.62 (m, 2H), 1.50 (s, 9H). MS=422 (MH)+. 34b) To a solution of 4-[2-(4-methoxy-phenylamino)-[1,2,4]triazolo[1,5-a]pyridin-8-yl]-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (100.0 mg, 0.2372 mmol) in dichloromethane (2 mL, 30 mmol) was added trifluoroacetic Acid (1 mL, 10 mmol). The mixture was stirred at room temperature for 4 days then evaporated to a resin. The residue was dissolved in dichloromethane (20 mL) and stirred with saturated aqueous potassium carbonate for 10 minutes. The organic layer was separated, dried over magnesium sulfate, filtered and evaporated. (4-Methoxy-phenyl)-[8-(1,2,3,6-tetrahydro-pyridin-4-yl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl]-amine was isolated yellow-brown resin (0.047 g, 62%) and was used without further purification. 1H NMR (400 MHz, CDCl3, δ, ppm): 8.29 (dd, J=6.6, 0.9 Hz, 1H), 7.52-7.47 (m, 2H), 7.32 (dd, J=7.4, 0.8 Hz, 1H), 7.29-7.25 (m, 1H), 6.94-6.89 (m, 2H), 6.83 (dd, J=7.2, 6.7 Hz, 1H), 6.71 (s, 1H), 3.81 (s, 3H), 3.68-3.64 (m, 2H), 3.17 (t, J=5.7 Hz, 2H), 2.61-2.55 (m, 2H). MS=322 (MH)+. 34c) To a solution of (4-methoxy-phenyl)-[8-(1,2,3,6-tetrahydro-pyridin-4-yl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl]-amine (47.0 mg, 0.146 mmol) and triethylamine (31.0 uL, 0.222 mmol) in dichloromethane (2 mL) was added dropwise methanesulfonyl chloride (14.0 L, 0.181 mmol). The mixture was stirred at room temperature for 1 hour then diluted with dichloromethane (20 mL) and water (20 mL). The organic was washed with water and saturated aqueous sodium bicarbonate (10 mL), dried over magnesium sulfate, filtered and evaporated. The residue was purified via chromatography using amine modified silica gel column (4.7 g) using 5%→100% ethyl acetate:hexane solvent gradient. The title compound, [8-(1-Methanesulfonyl-1,2,3,6-tetrahydro-pyridin-4-yl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl]-(4-methoxy-phenyl)-amine, was isolated as a yellow solid (0.037 g, 63%). MP=194-198° C. 1H NMR (400 MHz, CDCl3, δ, ppm): 8.33 (dd, J=6.6, 0.9 Hz, 1H), 7.52-7.47 (m, 2H), 7.32 (dd, J=7.5, 0.8 Hz, 1H), 7.29-7.25 (m, 1H), 6.94-6.89 (m, 2H), 6.86 (dd, J=7.5, 6.8 Hz, 1H), 6.73 (s, 1H), 4.10-4.06 (m, 2H), 3.81 (s, 3H), 3.57 (t, J=5.7 Hz, 2H), 2.87 (s, 3H), 2.84-2.78 (m, 2H). MS=400 (MH)+.
