| abstract |
A method of acylating 10-deacetylbaccatin III at the C-10 position over the C-7 hydroxy position thereof to produce baccatin III is accomplished first by dissolving 10-deacetylbaccatin III in an anhydrous ether solvent, such as tetrahydrofuran, at a reduced temperature, preferably -78° C. At least an equivalent of a lithium base, preferably about two equivalents n-butyl lithium, is next added followed by the addition of an acylating agent, such as acetyl chloride. The resulting solution is quenched, for example with ammonium chloride, to eliminate excess of the lithium base and the acylating agent. The result is baccatin III in solution. The baccatin III may be recovered by removing the ether solvent under vacuum to produce a residue that may then be dissolved, for example in ethyl acetate, with this solution being washed to remove unwanted salt compounds. Recrystallization and column chromatography may be employed to purify the baccatin III. |