Benzaldehyde → racemic 8-(1-benzylpiperidin-4-yl)-2-{(E)-2-[3-methoxy-4-(4-methyl-1H-imidazol-1-yl)phenyl]vinyl}-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-a]pyridine

Participants

Reaction Steps

Benzaldehyde (15 μl) and glacial acetic acid (16 μl) were added to a solution of racemic 2-{(E)-2-[3-methoxy-4-(4-methyl-1H-imidazol-1-yl)phenyl]vinyl}-8-(piperidin-4-yl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-a]pyridine obtained in Examples 118 and 119 (30 mg) in THF (2 ml), and the reaction solution was stirred at room temperature for 30 minutes. Sodium triacetoxyhydroborate (46 mg) was added to the reaction solution, and the reaction solution was stirred at room temperature for four hours. A saturated sodium bicarbonate solution and ethyl acetate were added to the reaction solution, and the organic layer was separated. The organic layer was washed with brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (carrier: Chromatorex™ NH; elution solvent: ethyl acetate) to obtain 27 mg of racemic 8-(1-benzylpiperidin-4-yl)-2-{(E)-2-[3-methoxy-4-(4-methyl-1H-imidazol-1-yl)phenyl]vinyl}-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-a]pyridine. Then, the racemate was separated by CHIRALPAK™ IB manufactured by Daicel Chemical Industries, Ltd. (2 cm×25 cm; mobile phase: 50% ethanol-hexane) to obtain the title optically active compound with a retention time of 14 minutes and positive optical rotation (9.4 mg; >99% ee) and the title optically active compound with a retention time of 20 minutes and negative optical rotation (8.9 mg; 99% ee).

Provenance & Evidence