NEW CEMBRANOID LACTONES FROM THE INDIAN-OCEAN SOFT CORAL SINULARIA-FLEXIBILIS

A detailed chemical examination of the Indian Ocean soft coral Sinular ia flexibilis yielded two new cembranolide epsilon-lactones, sandensol ide monoacetate (1) and flexibolide (4), in addition to the previously reported cembranolide delta-lactones, flexibilolide and dihydronexibi lolide, and the known cembranoid derivatives, sandensolide, cembrene A , and flexibilene. Their structures have been established by a study d f their spectral data (UV, IR, H-1 and C-13 NMR, 2D NMR (H-1-H-1, COSY and NOESY), and mass spectrometry.