SOLID-PHASE PEPTIDE SYNTHESIS OF ISOTOCIN WITH AMIDE OF ASPARAGINE PROTECTED WITH 1-TETRALINYL. TRIFLUOROMETHANESULPHONIC ACID (TFMSA) DEPROTECTION, CLEAVAGE AND AIR OXIDATION OF MERCAPTO GROUPS TO DISULPHIDE

Isotocin, a nonapeptide amide, was synthesised on a benzhydryl-resin using the Boc-strategy. Benzyl group was used in the protection of the side-chains of tyrosine, serine and cysteine. Tetralinyl group was used to protect asparagine side-chain. TFMSA-TFA-thioanisole-1,2-ethanedithiol (2:20:2:1 v/v) was used on the peptide-resin under different cleavage conditions to obtain isotocin in a one-pot reaction. The cleavage at 40 ° C for two hours gave isotocin quantitatively. Isotocin could be isolated in 61% yield. (Received February 13, 2001; revised August 31, 2001) Bull.Chem.Soc.Ethiop. 2001, 15(2), 143-15