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. Norisoprenoids were found from the sponge genus Spheciospongia for the first time, and were suggested to be the chemical marks for chemical taxonomy.