Antitumor Agents. V. Synthesis and Antileukemic Activity of E-Ring-Modified (RS)-Camptothecin Analogues

Several E-ring-modified analogues of (RS)-camptothecin were synthesized by total synthesis via Friedlander condensation and evaluated for cytotoxicity and antitumor activity against P388 mouse leukemia cells. Among them, (RS)-20-deoxyamino-7-ethyl-10-methoxycamptothecin (25c) was found to be more active than (RS)-camptothecin (1) in the in vivo assay.