284 mg (1.40 mmol) of {[(1-ethyl-1-methylpropoxy)carbonyl]-amino}-acetic acid, 320 mg (1.17 mmol) of 4-(5H-dibenzo[a,d][7]annulen-5-ylidene)-piperidine and 322 mg (1.68 mmol) of 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride were dissolved in a mixed solvent of 15 ml of dichloromethane and 5 ml of dimethylformamide. 0.23 ml (1.68 mmol) of triethylamine and 14.7 mg (0.12 mmol) of dimethylaminopyridine were added to the obtained solution, and they were stirred at room temperature overnight. After the concentration under reduced pressure, ethyl acetate was added to the reaction mixture. The resultant mixture was washed with saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure. The obtained residue was purified by the silica gel chromatography (hexane:dichloromethane=95:5 to 2:3) to obtain the title compound.
