Chemoselective thioacylation of amino acids. Preparation of the four monothiothymopentin analogs and their biological activity

Abstract A methodology for the specific site incorporation of thioamide linkages into a growing peptide under mild conditions using thioacylating agent 1 is described. Thus, the synthesis of the four monothioanalogues of thymopentin ( TP-5 ): [Valt 4 ]- 18 , [Aspt 3 ]- 19 , [Lyst 2 ]- 20 and [Argt 1 ]- 17 is reported. These thiopeptides retained the biological activity of the parent compound.