Veratrylamine → 7-Chloro-5-(3,4-dimethoxybenzylamino)-2-(2-furyl)[1,2,4]triazolo[1,5-c]pyrimidine

Into 600 mL of THF, 50.0 g (188 mmol) of Compound B was dissolved, and 42.0 mL (280 mmol) of DBU was added thereto, followed by stirring at room temperature for about 30 minutes. During the period, crystals were precipitated from the reaction solution. Next, 94 g (563 mmol) of 3,4-dimethoxybenzylamine was added thereto, followed by stirring at 60° C. for about 2 hours. After completion of the reaction, the solvent was evaporated, the residue was diluted with chloroform and washed with water, and the organic layer was dried over magnesium sulfate. The solvent was evaporated, and the resulting residue was triturated with ethyl acetate to obtain 53.2 g of Compound D as a white solid (yield: 74%). The residue obtained by concentrating the solution part present after trituration was purified by silica gel column chromatography (hexane/ethyl acetate=7/3) to additionally recover Compound D in about 10% yield.