Sinularianins A and B, novel sesquiterpenoids from the Formosan soft coral Sinularia sp.

Two novel sesquiterpenoids, sinularianins A and B (1 and 2), have been isolated from the Formosan coral Sinularia sp. The skeleton of sinularianins A (1), namely sinulariolane, was found to be unprecedented. Sinularianin B (2), with a novel spirobutenolide moiety, possesses a vaterenane skeleton, which had been reported mostly from the plant. The structures of both metabolites were established by extensive analysis of spectroscopic data. (c) 2006 Elsevier Ltd. All rights reserved.