1-Tetralinyl as carboxamine-protecting group for asparagine and application to N-a-t-Butyloxycarbonyl (Boc) solid-phase pentide synthesis of oxytocin

Abstract

Oxytocin, a nonapeptide amide, was synthesized on a benzhydryl-resin using the Boc strategy. Benzyl group was used in the protection of sulfhydryl group of cysteine and tyrosine side-chain. Benzhydryl and tetralinyl groups were used in the protection of glutamine and asparagine side-chains respectively. TFMSA-TFA-thioanisole-I,2- ethanedithiol (2:20:2:1 v/v) was used on the peptide-resin under different cleavage conditions to obtain oxytocin in a one-pot reaction. The cleavage at 40°C for two hours gave oxytocin quantitatively. Oxytocin could be isolated in 56% yield