Total synthesis of cis,cis-ceratospongamide, a bioactive thiazole-containing cyclic peptide from marine origin

The first total synthesis of cis,cis-ceratospongamide (1a), isolated from m arine source, was accomplished via thiazole synthesis using CMD methodology , DEPC-mediated peptide coupling, macrolactamization, and cyclodehydration. Comparison of the cyclization sites and coupling reagents in the macrolact amization step was also investigated.