Protection of the Amide Side-Chain of Asparagine with the 1-Tetralinyl Group in the Solid-Phase Peptide Synthesis of Lysine-Vasopressin

Lysine-vasopressin, a nonapeptide, was synthesised on a benzhydryl-resin using solid-phase peptide synthesis via the Boc-strategy. The benzyl group was used in the protection of the side-chains of tyrosine and cysteine, while 1-tetralinyl, benzhydryl and benzyloxycarbonyl groups were used in the protection of the side-chains of asparagine, glutamine and lysine, respectively. Thioanisole-1,2-ethanedithiol-trifluoroacetic acid-trifluoromethanesulphonic acid (2:1:20:2 v/v) was used to cleave the peptide-resin under different temperature conditions. The cleavage at 40 ºC for two hours gave lysine-vasopressin in a one-pot reaction; the yield after reversed-phase HPLC purification was 62%. South African Journal of Chemistry Vol.55 2002: 87-9