A 678 mg portion of [(1-trityl-1H-imidazol-4-yl)methyl]amine was dissolved in 10.0 ml of acetonitrile, and 0.52 ml of diisopropylethylamine and 316 mg of the 6-chloro-N-(4-fluorophenyl)-N′-phenyl-1,3,5-triazine-2,4-diamine synthesized in Reference Example 1 were added thereto and stirred at 80° C. for 3 days. After cooling down to room temperature, the reaction solution was mixed with water and extracted with ethyl acetate. The organic layer was washed with citric acid aqueous solution and saturated brine and dried using anhydrous magnesium sulfate. The solvent was evaporated under a reduced pressure, and the thus obtained residue was applied to a silica gel column chromatography and eluted with chloroform:methanol (99:1) to obtain a crude product. This crude product was dissolved in 9 ml of acetic acid and 1 ml of water and stirred at 70° C. for 2 hours. After evaporation of the reaction solution under a reduced pressure, the residue was mixed with ethyl acetate and sodium bicarbonate aqueous solution in that order and extracted with ethyl acetate. The organic layer was washed with saturated brine and dried using anhydrous magnesium sulfate. The solvent was evaporated under a reduced pressure, and the thus obtained residue was applied to a silica gel column chromatography and eluted with chloroform:methanol (90:10) to obtain a crude product. This crued product was dissolved in ethyl acetate and mixed with 4 M hydrochloric acid ethyl acetate solution, and the thus formed crystals were collected by filtration and dried to obtain 306 mg of N-(4-fluorophenyl)-N′-(1H-imidazol-4-ylmethyl)-N″-phenyl-1,3,5-triazine-2,4,6-triamine hydrochloride as colorless crystals.
