Sinulariols A-S, 19-oxygenated cembranoids from the Chinese soft coral Sinularia rigida

Chemical examination of a Chinese soft coral Sinularia rigida resulted in the isolation and characterization of 19 new cembrane-type diterpenoids, designated as sinulariols A-S (1-19). Their structures were determined on the basis of extensive spectroscopic (2D NMR, IR, and MS) analysis in association with modified Mosher's method. All compounds featured unusual 19-oxygenated functionalities, which are rarely found from cembranoid family. The biogenetic transformation of the isolated compounds is postulated. Part of the isolated cembranoids showed significant anti-fouling activity.