摘要
Two new norisoprenoid derivatives have been isolated from the red alga Gymnogongrus flabelliformis. Their structures were elucidated as （3R, 6R, 7E）-（＋）-3-O-phenylacetyl-4,7-megas- tigmadiene-9-one and （3R,TE）-（-）-3-O-phenylacetyl-5,7-megastigmadiene-9-one, respectively, by spectroscopic methods including HRMS, 1D and 2D NMR techniques.
Two new norisoprenoid derivatives have been isolated from the red alga Gymnogongrus flabelliformis. Their structures were elucidated as （3R, 6R, 7E）-（＋）-3-O-phenylacetyl-4,7-megas- tigmadiene-9-one and （3R,TE）-（-）-3-O-phenylacetyl-5,7-megastigmadiene-9-one, respectively, by spectroscopic methods including HRMS, 1D and 2D NMR techniques.
