Synthesis, structure elucidation and biological evaluation of C-norpaclitaxel

Abstract Oxidation of 2′-TBDMS-6α-hydroxy-7-epipaclitaxel ( 1 ) with lead tetraacetate furnished 2′-TBDMS-C-norpaclitaxel ( 2 ) and the C-seco compound 3. Deprotection of 2 with pyridinium hydrofluoride yielded Cnorpaclitaxel ( 4 ). C-norpaclitaxel ( 4 ) is less effective at promoting the assembly of microtubules and less cytotoxic towards HCT116 cells than paclitaxel.