Synthesis of the C-terminal tetrapeptide of the oxytocin sequence using various protective groups for the cysteine thiol function

The synthesis of amides of tetrapeptides with the 6–9 sequence of oxytocin containing various protective groups for the thiol function has been performed by 2+2 and 1+3 schemes. Relationships between the yield of tetrapeptide and the structures of the protective groups have been obtained. An advantage of trityl and benzyl protective groups for masking the tiol function of cysteine has been shown. The signals of the¹³C NMR spectra of the compounds obtained have been interpreted.All-Union Scientific-Research Institute of Blood Substitutes and Hormone Preparations, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 400–406, May–August, 1992.