Peroxypolasol and mugipolasol: two novel diterpenes from the marine sponge epipolasis sp

Two novel diterpenes, peroxypolasol (1) and mugipolasol (2), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1 and 2 were determined on the basis of spectroscopic data. Compound 1 is a diterpene with a peroxide ring in the side chain, and 2 is an unusual six/five-membered ring diterpene with an ethyl unit at C-2.