METABOLITES FROM THE MARINE SPONGE SPONGINELLA GRACILIS. THREE FURTHER NOR-DITERPENES, ONE OF THEM BASED ON A NOVEL CARBOCYCLIC SKELETON.

Article abstract of DOI:10.1016/S0040-4020(01)82087-1

Three new nor-diterpenes have been isolated from the Mediterranean sponge Spongionella gracilis and their structure have been determined by spectroscopic and chemical evidences.The structures of two of the new metabolites (3 and 4) are strictly related to gracilin A (2), a previously isolated nor-diterpene from the same source, whereas the third compound, spongionellin (1), possesses a new carbocyclic skeleton.The biogenesis of nor-diterpenes from S. gracilis is briefly discussed.