Into 2 ml of N,N-dimethylformamide was suspended 0.07 g of sodium hydride (60% oily), and 0.3 g of 3-(4-trifluoromethylpyridin-2-yl)-1,2,4-oxadiazol-5-one was added at room temperature. After stirring for 15 minutes, 0.35 g of chloromethyl 3-fluorobenzoate was added, and the mixture was stirred at 70° C. for 6 hours. The reaction solution was allowed to cool to room temperature, and poured into an aqueous saturated ammonium chloride solution, followed by extraction with ethyl acetate three times. The organic layers were combined, washed with an aqueous saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to obtain 0.12 g of [3-(4-trifluoromethylpyridin-2-yl)-1,2,4-oxadiazol-5-on-4-yl]methyl 3-fluorobenzoate (present compound (37)).
