Modified taxols. 5. Reaction of taxol with electrophilic reagents and preparation of a rearranged taxol derivative with tubulin assembly activity
摘要:
Reaction of the antineoplastic natural product taxol (1) with Meerwein's reagent leads to a product 4 with an opened oxetane ring. Reaction of taxol with acetyl chloride yields a product 16 in which the oxetane ring is opened and the A ring is contracted; a taxol derivative with a contracted A ring alone (22) can be prepared from taxol on treatment with mesyl chloride. The ring-contracted taxol derivative 22 shows comparable activity to taxol in a tubulin disassembly assay, but does not show significant cytotoxicity against KB cells in a cell culture assay; the derivatives 4 and 16 are inactive in both assays.