A solution of dimethylsulfoxide (0.30 mL, 4.2 mmol) in dichloromethane (1.0 mL) was added to a solution of oxalyl chloride (0.11 mL, 1.26 mmol) at −78° C. and the resulting mixture was stirred for 15 minutes. A solution of N-[4-[2-(1-hydroxyethyl)-4-(3-methylphenyl)-1,3-thiazol-5-yl]-2-pyridyl]propionamide (0.38 g, 1.0 mmol) in dichloromethane (1.5 mL) was added to the mixture and the resulting mixture was stirred for 45 minutes. The reaction mixture was allowed to warm up to −50° C. and triethylamine (0.72 mL, 5.17 mmol) was added dropwise to the mixture. The resulting mixture was stirred for 30 minutes and poured into aqueous sodium hydrogen carbonate. The mixture was extracted with ethyl acetate and the extracts were washed with aqueous sodium hydrogen carbonate solution and brine. The resulting solution was dried, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane-ethyl acetate=2:1) to obtain a crude crystal. The obtained crude crystal was recrystallized from isopropyl ether to give a title compound (0.22 g, yield 58%).
