Novel bromopyrrole alkaloids from the sponge Agelas dispar.

Further investigation of the Caribbean marine sponge Agelas dispar for biologically active constituents has led to the isolation of the novel bromopyrrole alkaloids longamide B (1), and clathramides C (2) and D (3), whose structures have been determined by spectroscopic methods. Isolation of the known keramadine (4) and of the ecdysonic sterols ecdysterone (5) and ajugasterone C (6) is also reported. The antimicrobial activities of the isolated bromopyrrole alkaloids is summarized.