Under a nitrogen atmosphere, triethylamine (1.08 ml, 7.8 mmol) and methanesulfonyl chloride (0.52 ml, 6.8 mmol) were added to a methylene chloride solution (30 ml) of the 2-[(2,5-difluorophenyl)-hydroxymethyl]-5-(1,3-dioxolan-2-yl)pyridine (1.52 g, 5.2 mmol) obtained in Referential Example 22 under ice cooling. The resulting mixture was stirred at room temperature for 3 hours. After addition of a saturated aqueous solution of sodium bicarbonate, the resulting mixture was extracted with ether. The extract was washed with brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue thus obtained was dissolved in dimethylformamide (30 ml). To the resulting solution were added chlorobenzenethiol (901 mg, 6.2 mmol) and potassium carbonate (1.08 g, 7.8 mmol), followed by stirring at 60° C. for 3 hours. After cooling to room temperature, the reaction mixture was diluted with ether. The diluted solution was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue thus obtained was purified by silica gel chromatography (hexane:ethyl acetate=5:1) to give the title compound (1.56 g, 71%) as colorless needle crystals.
