Preparation and biological activity of taxol acetates.

Synthesis and biological activity of 2'-acetyltaxol and 7-acetyltaxol are reported. Activity is measured in vivo by cytotoxicity toward the macrophage-like cell line J774.2, and in vitro by promotion of microtubule assembly in the absence of exogenous GTP. Addition of an acetyl moiety at C-2' results in loss of in vitro activity but not cytotoxicity. The properties of 7-acetyltaxol are similar to those of taxol in its effects on cell replication and on in vitro microtubule polymerization. Therefore a free hydroxyl group at C-7 is not required for in vitro activity and this position is available for structural modifications.