To a suspension of 200 mg of N-[2-(5-bromo-3-chloropyridin-2-yl)-2-(hydroxyimino)ethyl]-2-(trifluoromethyl)benzamide and 189 mg of potassium carbonate in 1 ml of N,N-dimethylformamide, 97 mg of iodomethane was added, and the mixture was stirred at room temperature for 23 hours. After completion of the reaction, the reaction mixture was mixed with 10 ml of water and extracted with ethyl acetate (20 ml×2), the resulting organic layers were combined, washed with water (10 ml×2) and dried over saturated aqueous sodium chloride and then anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The resulting residue was purified by silica gel column chromatography using ethyl acetate-hexane (with a gradient of from 5:95 to 50:50) as the eluent to obtain 143 mg of the desired product as a pale yellow resinous substance.
