Actinobenzoquinoline and Actinophenanthrolines A–C, Unprecedented Alkaloids from a Marine Actinobacterium

Chemical investigation of a marine actinomycete within the family Streptomycetaceae (our strain CNQ-149) has led to the isolation of the unprecedented alkaloids, actinobenzoquinoline (1) and actinophenanthrolines A–C (2–4). The chemical structures of 1–4 were assigned by interpretation of NMR spectroscopic data, and their absolute configurations were assigned by X-ray analysis. Actinobenzoquinoline possesses a 5-methyloxazolidin-4-one moiety and a dihydrobenzo[h]quinoline core structure, while actinophenanthrolines A–C are composed of hydroxypropanamide-substituted 1,7-phenanthroline core skeletons.