Antitumor agents. Part 232: Synthesis of cyclosulfite podophyllotoxin analogues as novel prototype antitumor agents

An 11,13-O,O′-cyclosulfite GL-331 analogue (7) was synthesized in six steps from podophyllotoxin and evaluated as a potential antitumor agent. Compound 7 was significantly cytotoxic against human tumor cell lines, but showed no inhibition against human DNA topoisomerase II in vitro. This compound represents a novel prototype of antitumor podophyllotoxin analogues.