To a mixture of 2-methyl-1-[6-(5-{1-[5-(methylsulfanyl)pyridin-2-yl]-2-(tetrahydro-2H-pyran-4-yl)ethyl}-1H-pyrrol-2-yl)pyridin-3-yl]propane-1,2-diol (0.37 g), water (4 mL) and acetonitrile (6 mL) was added sodium percarbonate (0.25 g), and the mixture was stirred at room temperature for 2 hr. To the reaction mixture was added sodium percarbonate (0.10 g), and the mixture was stirred at room temperature for 1 hr. To the reaction mixture was added saturated aqueous sodium sulfite solution, 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 basic silica gel column chromatography, and the title compound (0.33 g, yield 84%) was obtained as a pale-yellow amorphous solid from a fraction eluted with tetrahydrofuran-hexane (4:1, volume ratio). MS: 500 (MH+).
