Synthesis of oxytocin analogues modified in the tripeptide side-chain by condensation of aminoterminal linear hexapeptide with the carboxyterminal tripeptide

Abstract

For the synthesis of oxytocin (Ia) analogues modified in the carboxyterminal part of the molecule, a method based on the condensation of protected aminoterminal hexapeptide with tripeptides by the action of dicyclohexylcarbodiimide and pentafluorophenol in the presence of 1-hydroxybenzotriazole was devised. Using this method [7-[U-13C]proline]oxytocin (Ib), des-9-glycine-oxytocin (Ic) and methyl ester of oxytocinoic acid ([9-glycine methyl ester]oxytocin) (Id) were prepared.