Note
Fused ring alkaloids having the pyridol[4,3,2-mn]acridine skeleton comprise a new class of marine natural products.1a–h Their biological activity1e and challenging structure elucidation make them an interesting group of compounds. In this paper we report the identification of four newcytotoxic and structurally related alkaloids: nordercitin (1), dercitamine (2), dercitamide (3), and cyclodercitin (4).