Chemistry of Benzo [c] phenanthridine Alkaloids having Antineoplastic Activity

Abstract
The recent progress of the chemistry of benzo[c]phenanthridine alkaloids was reviewed. Structural establishment of 4 new naturally occurring amides, arnottianamide, isoarnottianamide, integriamide and iwamide, was performed by deriving from chelerythrine, nitidine, avicine and decarine, respectively, by using the Baeyer-Villiger type oxidation of an immonium group, develop. The fully aromatized O5-benzo[c]phenanthridine alkaloids, chelirubine, cheliutine, sanguilutine, and sanguirubine, were synthesized by photo-cyclization of an enamide or by the revised Robinson method. In general, this revised method is also applicable to the synthesis of the 8,9-oxygenated O4-bases, for example nitidine was prepared by this method in 40% total yield. The induced shift of 1H-NMR signals of oxybases is discussed.