To 165 mg (0.250 mmol) of 4-(4,4-Difluorocyclohexyl)-3-{fluoro[4-(trifluoromethyl)phenyl]methyl}-2-[1-(5-formyl pyrimidin-2-yl)piperidin-4-yl]-7,7-dimethyl-5,6,7,8-tetrahydroquinolin-5-ol, which was prepared by a method similar to that of Example (36-1), 1.0 ml of methanol, 0.1 ml of tetrahydrofuran and 0.20 ml (about 2.5 mmol) of about 40% methylamine-methanol solution were added, and the reaction solution was stirred at room temperature for 12 hours. Then, 95 mg (2.5 mmol) of sodium borohydride was added thereto and the reaction solution was stirred at room temperature for 1 hour. After completion of the reaction, saturated ammonium chloride aqueous solution was poured into the reaction solution until the bubbling disappeared. Saturated sodium hydrogencarbonate aqueous solution was poured into the reaction solution to make the reaction solution basic and the reaction solution was extracted with ethyl acetate. The organic layer was washed with saturated sodium chloride aqueous solution and dried with anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure. The obtained residue was subjected to silica gel column chromatography [dichloromethane/methanol/28% ammonia water=100/0/0-90/9.5/0.5 (V/V/V)] and the fraction including the desired compound was concentrated under reduced pressure to provide 128 mg of the title compound as a colorless oil (yield: 76%).
