Isolialitulin and Haliclorensins B and C, Three Marine Alkaloids from Haliclona tulearensis

Three new alkaloids, designated isohalitulin (4), haliclorensin B (5). and haliclorensin C (6), were isolated from two specimens of the Madagascan Sponge Haliclona tulearemsis, collected ill two locations in Salary Bay, north of Tulear. Their structures were elucidated by extensive spectroscopic means. Alkaloids 4-6 exhibited mild toxicity ill the brine shrimp test.