17.4 g (0.05 mol) of glycyl-L-tyrosine ethyl ester·HBr, 9 g (0.05 mol) of p-acetoxybenzoic acid and 5.1 g (0.05 mol) of triethylamine were dissolved in 250 ml of dichloromethane, and after the solution was cooled to 0° C., 9.6 g (0.05 mol) of 1-ethyl-3(3-dimethylaminopropyl)carbodiimide·HCl was added to the solution, and the solution was stirred overnight. The reaction mixture was washed with a 0.1% aqueous solution of Na2CO3 and with a 0.1 N HCl solution, and was dried over anhydrous sodium sulfate. Dichloromethane was removed from the mixture under reduced pressure to obtain p-acetoxybenzoylglycyl-L-tyrosine ethyl ester.
