SMENOCHROMENES, UNUSUAL MACROCYCLIC SESQUITERPENE HYDROQUINONE DERIVATIVES FROM A SEYCHELLES SPONGE OF THE GENUS SMENOSPONGIA

Smenochromenes A-D (2-5) are four unusual macrocyclic chromenes that can be derived by cyclization of farnesyl hydroquinone. The structure of smenochromene A (2) was determined by X-ray analysis and the structures of the remaining compounds were elucidated by interpretation of spectral data. The unusual geometry of smenochromene A gives rise to some unexpected spectral data. The sponge Smenospongia sp. also contains smenodiol (6), which is related to compounds previously found in this genus.