SEMISYNTHESIS OF SOME 7-DEOXYPACLITAXEL ANALOGS FROM TAXINE-B

Taxine B (3), isolated from the dried needles of Taxus baccata, was co nverted into six novel 7-deoxypaclitaxel analogs, 20, 21a,b, and 23-25 , that have structural changes at C1, C2, and C4. A method for the int roduction of the benzoyl function at C2, via a benzylidene acetal at C 1-C2, will be revealed. All compounds showed very little or no measura ble cytotoxic activity against some well-characterized human tumor cel l lines, probably due to the nonacylated hydroxyl group at C4.