Amphidinolides B6 and B7, cytotoxic macrolides from a symbiotic dinoflagellate Amphidinium species.

Two 26-membered macrolides, amphidinolides B6 ( 2) and B7 ( 1), have been isolated from a marine symbiotic dinoflagellate Amphidinium sp., and the structures were elucidated on the basis of detailed analyses of 2D NMR data. The relative and absolute configurations for 1 and 2 were assigned by comparison of NMR data and CD data with those of known amphidinolides.