Base-mediated transformations of 3,5-dibromoverongiaquinolfrom the sponge Aplysina sp. to cavernicolins-1, -2 and a subereatensin analogue

摘要

Treatment of 3,5-dibromoverongiaquinol (1) with NaHCO3-MeOH at room temperature gave cavernicolin-1 (2), cavernicolin-2 (3), the 4,7-dimethoxy analogue of subereatensin (4) and dimethyl ketal (5). These transformations may clarify the origin of the cavernicolins and subereatensin isolated from the extracts of some verongid sponges.