A new cyclized 9,11-secosterol enol-ether from the australian sponge euryspongia arenaria

The polar fraction of the crude extract from the sponge Euryspongia arenaria was separated by chromatography. Structure elucidation by spectrometric methods allowed the identification of a new steroid, stellattasterenol (2), containing an unprecedented seven-membered cyclic enol-ether in ring C. A related known compound, stellettasterol (3), a pentahydroxy-9,11-secosteroid, was also identified.