Radical Cyclization ofN-Acylcyanamides: Total Synthesis of Luotonin A

Synthesis and topoisomerase poisoning activity of A-ring and E-ring substituted luotonin A derivatives

A series of A-ring and E-ring analogues of the natural product luotonin A, a known topoisomerase I poison, was evaluated for growth inhibition in human carcinoma and leukemia cell lines. Rational design of structures was based on analogues of the related alkaloid camptothecin, which has been demonstrated to exert cytotoxic effects by the same mechanism of action. When compared to luotonin A, several compounds exhibited an improved topoisomerase I-dependent growth inhibition of a human leukemia cell line.

Total synthesis of luotonin A and 14-substituted analogues

A new and concise synthesis of luotonin A was achieved from the previously described compounds ethyl 4-oxo-3,4-dihydroquinazoline-2-carboxylate and 1-(2-nitrophenyl)prop-2-en-1-one. New 14-substituted luotonin A analogues were prepared using 14-chloroluotonin A as the key intermediate.