Abstract
The synthesis of sequence 71-86 of human proinsulin (sequence 6-21 of human insulin A-chain) via its monomeric cyclic dicystine peptide derivative and the corresponding tetra-S-trityl-peptide derivative is described. Good solubility of the derivatives in organic solvents makes it possible to purify both in their protected forms. The S-trityl derivative enables synthesis of the fragment 71-86 in a scale needed for planned synthesis of human proinsulin.