Norisoprenoids from the marine sponge Spheciospongia sp.

Chemical examination of a marine sponge Spheciospongia sp. collected from South China Sea resulted in the isolation of five norisoprenoid derivatives (1-5), of which two new compounds were designated with trivial names of spheciospongones A (1) and B (2). Their structures were determined on the basis of extensive 1D and 2D NMR, and MS spectroscopic data analysis in association with circular dichroism.