Triethylamine → Ethyl ((benzyloxy)carbonyl)-L-phenylalanylglycinate

Glycine ethyl ester.hydrochloride in an amount of 20.6 g was dissolved in 500 ml of chloroform and 20 ml of triethylamine was added thereto. Then, 57.2 g of carbobenzoxyphenylalanine p-nitorphenyl ester was added to the resulting mixture and the reaction was carried out overnight at room temperaure. The resulting mixture was washed with IN-NaHCO3, water, IN-HCl and water in this order and the chloroform layer was dried over magnesium sulfate MgSO4). After removing the solvent by distillation, the residue was recrystallized from ethyl acetate and petroleum ether to give carbobenzoxy-phenylalanyl-glycine ethyl ester having a melting point of 110°-112° C. in yield of 40.5 g (81%).