Sesquiterpenes from marine sponge Dysidea fragilis

By various chromatographic separations, three sesquiterpenes, furodysinin lactone (1), O-methyl furodysinin lactone (2) and O-methyl-9-oxofurodysinin lactone (3) were isolated from Vietnamese marine sponge Dysidea fragilis. Their structures were determined by 1D-, 2D-NMR spectra and in comparison with the reported data. Compound 3 was reported from sponge D. fragilis for the first time