134 mg (0.70 mmol) of 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride, 176 mg (0.59 mmol) of protriptyline hydrochloride and 0.176 ml (1.26 mmol) of triethylamine were added to 129 mg (0.74 mmol) of t-butoxycarbonylglycine in 5 ml of dichloromethane, and they were stirred at room temperature overnight. Saturated aqueous sodium hydrogencarbonate solution was added to the reaction mixture. After extracting with dichloromethane, 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 obtain the title compound.
