Combinatorial Synthesis and Biological Evaluation of Destruxins.

The combinatorial synthesis and biological evaluation of destruxins are described herein. First, the total synthesis of destruxin E was achieved, and its absolute configuration was successfully determined to be (S). In addition, the preparation of a combinatorial library based on the structure of destruxins was carried out by the split-and-pool method. Biological evaluation of the resulting analogs against osteoclast-like multinuclear cells (OCLs) revealed that the N-methyl-alanine residue was crucial to inducing morphological changes in OCLs. In particular, functionalization at the β-position of the proline (Pro) residue was found to be tolerant of the desired biological activity of destruxin E, suggesting that the β-position of the Pro residue should be a promising site for the introduction of a chemical tag toward the preparation of a molecular probe.