To a solution of 0.11 g of 3-(4-aminomethyl-3-chlorophenyl)-5-(3,4,5-trichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazole, 0.051 g of (methylthio) acetic acid and 0.048 g of triethylamine in 2 mL of chloroform, 0.092 g of 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride was added and the resultant mixture was stirred at room temperature for 15 hours. After the completion of the reaction, 2 mL of a saturated sodium hydrogen carbonate aqueous solution was added to the reaction mixture and the organic phase was separated off, followed by purifying the organic phase as it was by preparative medium pressure liquid chromatography eluting with ethyl acetate-hexane (a gradient from 1:4 to 1:1) using a medium pressure preparative apparatus (trade name: YFLC-Wprep; manufactured by Yamazen Corporation) to obtain 0.12 g of the objective substance as a colorless resinoid.
