Two New Cembrane-Based Diterpenoids from the Marine Soft Coral Sinularia crassa

Two new cembrane diterpenes, sicrassarines A and B (compounds 1 and 2), were isolated from the Taiwanese soft coral Sinularia crassa. The structures of the new metabolites were determined on the basis of extensive spectroscopic analysis, particularly mass spectroscopy and 2D NMR (H-1-H-1 COSY, HMQC, HMBC, and NOESY) spectroscopy.