240 mg (0.78 mmol) of 4-[4-(3-cyanophenoxy)butyryl]benzoic acid, 150 mg (0.78 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 121 mg (0.78 mmol) of 1-hydroxybenzotriazole (hydrous, 87%) and 100 mg of 50% aqueous dimethylamine solution were stirred together in 5 ml of dimethylformamide at room temperature overnight. 1 N hydrochloric acid was added to the resultant mixture. After the extraction with dichloromethane, the extract was washed with saturated aqueous sodium hydrogencarbonate solution and then with saturated aqueous NaCl solution, and dried over anhydrous magnesium sulfate. The solvent was evaporated. The residue was purified by the silica gel chromatography with ethyl acetate as the eluent to obtain the title compound.
