New Nor-Isomalabaricanic Acids from the Vietnamese Marine Sponge Rhabdastrella globostellata
摘要
New nor-isomalabaricanic acids 1 and 2 were isolated from polar fractions of the EtOH extract of the Vietnamese sponge Rhabdastrella globostellata using a combination of column chromatography and reversed-phase HPLC. The chemical structures of the new compounds, which were called stellettins W (1) and X (2), were elucidated by analyzing data from NMR experiments and HR-ESI-MS spectra and by comparison with the structures of associated isolated metabolites. Stellettin W was the first isomalabaricane derivative with a 13,14-epoxide group in its structure.