A solution of 0.80 g of N-(2-pyridylmethyl)-4-acetylamino-3-aminobenzamide in 10 ml of N,N-dimethylformamide were added 0.962 g of 3,4-methylenedioxybenzyl chloride and 0.710 g of sodium hydrogencarbonate, and the mixture was stirred at 80° C. for 4 hours. Chloroform and water were added to the reaction solution, and the chloroform extraction was conducted. The organic layer was washed with water, concentrated, and purified through silica-gel column chromatography (eluent: a mixture of ethyl acetate and methanol at a ratio of 9:1) to give 0.49 g of N-(2-pyridylmethyl)-4-acetylamino-3-(3,4-methylenedioxybenzylamino)benzamide.
