N-(2-Nitrobenzenesulfonyl)-N-[[2-(3,4,5-trimethoxy-phenyl)pyridin-4-yl]methyl]glycine methyl ester (11.35 g) was dissolved in acetonitrile (30 mL), and to the solution potassium carbonate (3.39 g) was added. Thiophenol (2.37 g) was then added to the mixture, and the resultant mixture was stirred overnight at room temperature. Ethyl acetate was added to the reaction mixture, and the resultant mixture was washed with a saturated aqueous solution of sodium hydrogencarbonate, water and saturated brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was then purified by column chromatography on silica gel (chloroform:methanol=20:1) to obtain the title compound.
