A mixture of 0.35 g of 2-methylamino-5-trifluoromethylpyridine, 0.50 g of 3-ethylsulfanyl-5-trifluoromethylpicolinic acid, 0.46 g of EDCI hydrochloride, 0.02 g of HOBt and 3 mL of pyridine was stirred at room temperature for 3 hours. A saturated aqueous sodium bicarbonate solution was poured to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure, and the resulting residue was applied to a silica gel column chromatography to obtain 0.18 g of 3-ethylsulfanyl-N-methyl-5-trifluoromethyl-N-(5-trifluoromethylpyridin-2-yl)picolinamide (hereinafter, referred to as Compound of Present Invention 24).
