11,20-Epoxybriaranes from the gorgonian coral Ellisella robusta (Ellisellidae).

Chemical investigation on the organic extract of the gorgonian coral Ellisella robusta furnished two 11,20-epoxybriaranes 1 and 2. The structures of briaranes 1 and 2 were assigned on the basis of spectroscopic evidence. The natural products of this type (11,20-epoxybriarane) were found to be a chemical marker for the gorgonian corals belonging to the family Ellisellidae.