A reassignment of (-)-mycothiazole and the isolation of a related diol

A reinvestigation of the thiazole constituents from Cacospongia mycofijiensis, collected in Vanuatu, yielded known mycothiazole (3) plus a new derivative, mycothiazole-4,19-diol (6). The E stereochemistry at Delta(14,11) of 3 has been revised to Z and the structural features of 6 are elucidated. These compounds, which presumably arise by the action of a polyketide-nonribosomal peptide synthetase (PKS/NRPS) hybrid, possess cytotoxic properties that need further exploration.