Studies of Australian Ascidians. VI. Virenamides D and E, Linear Peptides from the Colonial Didemnid Ascidian Diplosoma virens

Abstract

Two new linear cytotoxic tripeptides, virenamides D and E, have been isolated as minor constituents of extracts of the didemnid ascidianDiplosoma virens collected on the Great Barrier Reef, Australia. Their structures were deduced from one-dimensional and two-dimensional n.m.r. spectroscopic data, and the absolute stereochemistry of virenamide E is proven by synthesis from virenamide A.