[Use of oximinoiminopyrrazoline esters in the synthesis of solids phase peptides: synthesis of bradykinin].

Since oximinyliminopyrrazoline ester (OPmp) present a peculiar characteristic in the omogenous peptide synthesis, the use of them, also in the synthesis of bradikinine by the solid phase technique, was duly taken into consideration and tried out. This synthesis was achieved by employing N-protected amino acid OPmp esters containing a methoxycarbonyl or a benzylaminocarbonyl as the acyl function in position 5 of the pyrazoline ring. No significant differences were found in the reactivity of such derivatives in respect of OPmp esters containing the benzyloxycarbonylglycyl moiety. The biological activity of the synthetized braikinine is similar to that of a sample of natural "standard".