A Two-Step Synthesis of Cytostatically Active Benzo[c]phenanthridine Derivatives

摘要

The benzo[c]phenanthridine class of substances display a variety of pharmacological properties. A large number of naturally occurring alkaloids that contain a benzo[c]phenanthridine ring system and have a known spectrum of activity are mentioned in the literature.[1], [2] Aside from fagaronine (1), the most important representative of this group of natural products, other alkaloids with extensive pharmacological potential are nitidine (2), chelerythrine (3), and sanguinarine (4; Scheme 1).[3]-[5] The synthesis of these natural products is of great interest, because they can be isolated from plant materials only in very small amounts. Cushman et al.[6] describe yields in the 0.003 to 0.07 % range for the isolation of 2 from a series of zanthoxylum and fagara varieties. Compound 1 was first isolated from the root of Fagara zanthoxyloides in 1972.