To a solution of 6-(5-{1-[4-(cyclopropylsulfonyl)phenyl]-2-(tetrahydro-2H-pyran-4-yl)ethyl}-1H-pyrrol-2-yl)pyridine-3-carbaldehyde (200 mg) in 1,2-dichloroethane (3 mL) was added (3S)-1-acetyl-3-methylpiperazine (140 mg), and the mixture was stirred at room temperature for 30 min. To the reaction mixture was added sodium triacetoxyborohydride (273 mg), and the mixture was stirred at room temperature for 3 hr. The reaction mixture was diluted with ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate and saturated brine, dried (MgSO4) and concentrated. The residue was subjected to basic silica gel column chromatography, and the title compound (184 mg, yield 72%) was obtained as a colorless amorphous solid from a fraction eluted with ethyl acetate. MS: 591 (MH+).
