A novel elemane-type sesquiterpenoid lactam Clavulinin

Many interesting compounds with novel structures and possessing biological activitieshave been isolated from soft coral of genus Clavularia.From the soft coral Clavulariaviridis we have isolated eight new diterpenes and a new sterol.Some of them exhibitedantitumor activity.In a continuation of systematic investigation on the chemical con-stituents of soft corals,we isolated a new sesquterpenoid named clavulinin (1) from thesoft coral Clavularia inflata Schenk.Its structure was determined mainly on the basis ofspectral analysis.Clavulinin is a member of elemane-type sesquiterpene acid ester containinga very rare γ-hydroxy-α,β-butalactam system.