Novel A-ring modified camptothecins as topoisomerase I inhibitors

Novel A-ring modified camptothecins as topoisomerase I inhibitors Synthesis and Antitumor Activity of Ring A- and F-Modified Hexacyclic Camptothecin Analogues Novel hexacyclic camptothecin derivatives. Part 1: Synthesis and cytotoxicity of camptothecins with an A-ring fused 1,3-oxazine ring Synthesis, Topoisomerase I Inhibitory Activity, and in Vivo Evaluation of 11-Azacamptothecin Analogs Water Soluble Inhibitors of Topoisomerase I:  Quaternary Salt Derivatives of Camptothecin BN 80245: An E-ring modified camptothecin with potent antiproliferative and topoisomerase I inhibitory activities Modification of the hydroxylactone ring of camptothecin: inhibition of mammalian topoisomerase I and biological activity Synthesis and pharmacological evaluation of novel non-lactone analogues of camptothecin Synthesis and Antitumor Activity of Novel Water Soluble Derivatives of Camptothecin as Specific Inhibitors of Topoisomerase I Synthesis and Biological Evaluation of Novel A-Ring Modified Hexacyclic Camptothecin Analogues