| abstract |
The present invention relates to a process for the preparation of paclitaxel, represented by the following formula 1: characterized in that (a) the oxazolidine derivative represented by the following formula 2 or a salt thereof: in which X represents halogen, is coupled to 7-trihaloacetyl-bacatin III, represented by the following formula 3: wherein R 1 denotes trichloroacetyl, in a solvent and in the presence of a condensing agent, to obtain a taxane, containing oxazolidine as a substituent, represented by the following formula 4: wherein X and R 1 have the meanings defined previously; (b) the oxazolidine ring is opened in a solvent in the presence of an acid, and the product thus obtained is reacted with benzoyl chloride in the presence of a single base to give a trihaloacetyl-protected paclitaxel, represented by the following formula 5: wherein R 1 is as previously defined; (c) then the protecting group is removed from the 7-position with ammonia or ammonia salt, with a weak acid in the solvent. |