Design, Synthesis and Biological Activity of (20S, 21S)-7-Cyclohexyl-21-fluorocamptothecin Carbamates as Potential Antitumor Agents.

(20S, 21S)-7-Cyclohexyl-21-fluorocamptothecin 6 was discovered by a fluorine drug design strategy with potent antitumor activity and increased metabolic stability. In continuous efforts to find novel antitumor agents derived from natural product camptothecin, 20-carbamates of active compound 6 have been designed and synthesized. Among them, compound 10g with diethyl group shows greater antiproliferative activity than the other 20-carbamate derivatives. The following biological activity assays indicates that compound 10g is a valuable lead compound with excellent Topo I inhibitory activity and solution stability.