Total Synthesis and Antibacterial Study of Cyclohexapeptides Desotamide B, Wollamide B and Their Analogs.

As natural-product-derived antibiotics, desotamides A - D and wollamides exhibit growth inhibitory activity against Gram-posivite bacteria (IC50 0.6 - 7 μm) and are noncytotoxic to mammalian cells (IC50  > 30 μm). Herein we firstly report the total synthesis of above two cyclohexapeptides as well as a series of structural variants through solid phase peptide synthesis, of which 3 displayed a 2-fold increase of antibacterial activity when compared with the original peptide 1. This strategy may offer good improvements for the synthesis of other cyclic peptides.