Carbobenzyloxy (S-benzyl)cyteinyl (S-benzyl) cysteinylalanylglycylvalyl (S-benzyl) cysteinyl ethyl ester (Ⅱ), a derivative of the hexapeptide fragment (A_6-11) of A-Chain of insulin, had been prepared by coupling alanylglycylvalyl(S-benzyl)cysteinyl ethyl ester with carbo-benryloxy(S-benzyl)cysteinyl(S-benryl)cysteine by the carbodiimide or the mixed anhydride methods respectively. This paper reports that the same peptide can also be prepared by the azide method, but with much better yield and without the formation of the amide. Using the same method we have also prepared three other analogous hexapeptides, namely, carbobenryloxy (S-benryl) cysteinyl-alanylalanylglycylvalyl (S-benzyl) cysteinyl ethyl ester (Ⅷ), carbobenzyloxy(S-benzyl)cysteinylleucylalanylglycylvalyl (S-benryl) cysteinyl ethyl ester (Ⅸ), and carbobenryloxy(S-benryl)cysteinylglycylalanylglycylvalyl(S-benzyl)cysteinyl ethyl ester (Ⅹ) with excellent results.