Cyclic peptides. II. Synthesis of a cyclodepsipeptide, rotodestruxin

Synthesis of a cyclohexadepsipeptide corresponding to the sequence of protodestruxin from linear hexapeptides was attempted through five different routes in a conventional method, and three routes afforded the same cyclopeptide. Biological and physiocochemical properties of the synthetic peptide were identical to those of natural protodestruxin. Differences in the yields of the cyclization were explained through the assumed conformations of the linear hexapeptides.