Investigation of the Dimethylsulfoxide-Trifluoroacetic Acid Oxidation System for the Synthesis of Cystine-Containing Peptides

Disulfide bonds of peptides were effectively established between S-protected cysteine residues as well as free cysteine residues by the action of dimethylsulfoxide in trifluoroacetic acid. Oxytocin and a-human calcitonin gene-related peptide were synthesized using this oxidation system. The feasibility of this method for the formation of two disulfide bridges of apamin was also examined.