Studies on the chemical constituents of rutaceous plants. LX. Development of a versatile method for syntheses of the antitumor benzo(c)phenanthridine alkaloids. 9. Efficient syntheses and antitumor activities of nitidine and related nonphenolic benzo(c)phenanthridine alkaloids.

Several nonphenolic benzo [c] phenanthridine alkaloids including naturally occurring nitidine (1a) and avicine (1e) were synthesized in excellent yields through an efficient synthetic method developed by us. Antitumor activities of twelve alkaloids including four naturally occurring O5-alkaloids [chelilutine (1g), chelirubine (1h), sanguilutine (1k), and sanguirubine (11)] against Sarcoma 180 were tested. The structure-activity relationship of these alkaloids is discussed.