60.0 mg (0.110 mmol) of 4-(3-chlorophenyl)-6-[(2-cyclohexylethoxy)methyl]-2-phenyl-1,4-dihydropyrimidine-5-carboxylic acid and 34.9 mg (0.165 mmol) of 3,3-diphenylpropylamine were dissolved in 10 ml of dichloromethane. 31.6 mg (0.165 mmol) of WSC hydrochloride and 16.8 mg (0.110 mmol) of 1-hydroxybenzotriazole (hereinafter referred to as “HOBT”) were added to the obtained solution under cooling with ice, and they were stirred at room temperature overnight. The reaction mixture was diluted with dichloromethane and then washed with saturated aqueous sodium hydrogencarbonate solution. The organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The residue was purified by the silica gel chromatography (hexane/ethyl acetate=3/1 to 1/1) to obtain the title compound.
