In the same manner as in Example 13 (1), 1-((S)-3-(4-chloro-6-methyl-1-oxypyridin-2-ylamino)pyrrolidin-1-yl)-2-(4-trifluoromethoxyphenyl)ethanone (0.64 g) was obtained from 2,4-dichloro-6-methylpyridin-1-oxide (0.50 g) and 1-((S)-3-aminopyrrolidin-1-yl)-2-(4-trifluoromethoxyphenyl)ethanone mono hydrochloride (1.1 g). (2) A mixture of 1-((S)-3-(4-chloro-6-methyl-1-oxypyridin-2-ylamino)pyrrolidin-1-yl)-2-(4-trifluoromethoxyphenyl)ethanone (300 mg), 4-methylpiperidine (0.30 g), N,N-diisopropylethylamine (0.40 mL), and n-butanol (0.60 mL) was heated at 110° C. for 15 h. The mixture was cooled to room temperature, then the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (NH silica gel, ethyl acetate−ethyl acetate/methanol=10:1) to obtain the title compound (40 mg) and 1-((S)-3-(4,6′-dimethyl-1′-oxy-3,4,5,6-tetrahydro-2H-[1,4′]bipyridinyl-2′-ylamino)pyrrolidin-1-yl)-2-(4-trifluoromethoxyphenyl)ethanone (200 mg). (3) 1-((S)-3-(4,6′-Dimethyl-1′-oxy-3,4,5,6-tetrahydro-2H-[1,4′]bipyridinyl-2′-ylamino)pyrrolidin-1-yl)-2-(4-trifluoromethoxyphenyl)ethanone (200 mg) was dissolved in methanol (6 mL), followed by addition of 10% Pd—C (200 mg), and the mixture stirred overnight at 40° C. under hydrogen atmosphere. The catalyst was removed by Celite filtration, then the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (NH silica gel, chloroform/methanol=10:1) to obtain the title compound (64 mg).
