A mixture of 6-(5-{1-[4-(cyclopropylsulfonyl)phenyl]-2-(tetrahydro-2H-pyran-4-yl)ethyl}-1H-pyrrol-2-yl)pyridine-3-carbaldehyde (3.0 g), methyl (methylsulfinyl)methyl sulfide (2.43 g), 40% benzyltrimethylammonium hydroxide methanol solution (5 mL), and tetrahydrofuran (50 mL) was heated under reflux for 24 hr. Water was added to the reaction mixture and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. A mixture of the residue and 10% hydrogen chloride methanol solution (60 mL) was heated under reflux for 15 hr, and cooled to room temperature. To the reaction mixture was basified with saturated aqueous sodium hydrogen carbonate and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The residue was subjected to silica gel column chromatography, and the title compound (2.02 g, yield 64%) was obtained as a brown amorphous solid from a fraction eluted with ethyl acetate-hexane (1:1-2:1, volume ratio). MS: 509 (MH+).
