Synthesis and Biological Evaluation of Vioprolide B and Its Dehydrobutyrine-Glycine Analogue

Herein, we describe the total synthesis of the depsipeptide vioprolide B and of an analogue, in which the (E)-dehydrobutyrine amino acid was replaced by glycine. The compounds were studied in biological assays which revealed cytotoxicity solely for vioprolide B presumably by covalent binding to cysteine residues of elongation factor eEF1A1 and of chromatin assembly factor CHAF1A.