Agesasines A and B, Bromopyrrole Alkaloids from Marine Sponges spp.

Exploration for specialized metabolites of Okinawan marine sponges spp. resulted in the isolation of five new bromopyrrole alkaloids, agesasines A () and B (), 9-hydroxydihydrodispacamide (), 9-hydroxydihydrooroidin (), and 9-keramadine (). Their structures were elucidated on the basis of spectroscopic analyses. Agesasines A () and B () were assigned as rare bromopyrrole alkaloids lacking an aminoimidazole moiety, while - were elucidated to be linear bromopyrrole alkaloids with either aminoimidazolone, aminoimidazole, or -methylated aminoimidazole moieties.