Synthesis and Biological Properties of Luotonin a Derivatives

Abstract

A series of new derivatives on the ring A of luotonin A were prepared by Friedländer condensation of 6,7,8,10-tetrahydropyrrolo[2,1-b]quinazoline-6, 10-dione and suitably substituted 2-aminobenzaldehydes and 2-aminoacetophenones. Their inhibitory activities on topoisomerases and cytotoxicities against selected human cancer cell lines were evaluated. Among the compounds tested, 8-fluoroluotonin A showed similar inhibitory activity on topoisomerase I comparable to camptothecin while luotonin A and 9-hydroxyluotonin A showed 1.37 and 0.94 times stronger inhibitory activity, respectively, on topoisomerase II compared to etoposide. Some derivatives of luotonin A showed moderate cytotoxicity. The possible relationship between the inhibitory activity on Topo II and the cytotoxicity of luotonin A and its analogues, thus, cannot be ruled out.