Synthesis and cytotoxicity of podophyllotoxin analogues modified in the A ring.

Several podophyllotoxin derivatives lacking the methylenedioxy group or with different functionalization of the A-ring of the cyclolignan skeleton have been prepared and evaluated for their cytotoxic activities on four neoplastic cell lines (P-388, A-549, HT-29 and MEL-28). Most of them maintained their cytotoxicity at the microM level.