2. Taxol Skeleton

Taxol is made up of several rings: a six membered double bond containing (A) ring, an eight membered (B) ring, another six membered (C) ring and a four membered (D) ring. Modification of the taxol skeleton and studying it's activity has lead us to the following features:-

Removal of the C2, C7 and the C10 acetyl groups doesn't seem to have any effect on the activity.

Removing the C2-O-benzoyl group causes a drastic reduction in activity. Changing the eight membered (B) ring to a seven membered ring still provides

the molecule with tubulin depolymerization properties. The oxetane (B) ring is crucial in maintaining the molecules activity and ring

opening leads to a dramatic decrease in biological activity.

The following diagram summarises the structure-activity relationship of Taxol.