Sinulaspirolactam A, a novel aza-spirocyclic valerenane sesquiterpenoid from soft coral Sinularia sp.

AbstractA novel valerenane sesquiterpenoid sinulaspirolactam A (1), together with five known compounds, was isolated from the soft coral Sinularia sp. Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 was the first example of valerenane sesquiterpenoid bearing an aza-spiro[4.5] ring moiety, the plausible biogenetic pathway of which was proposed. Cytotoxic activities of these compounds were also evaluated.