METHOD OF PREPARING ESTERS OF BACCATINE III OR 10-DEACETYLBACCATINE III, ESTERS OF BACCATINE III OR 10-DEACETYLBACCATINE III, AND INTERMEDIATE FOR THIS METHOD

摘要

Disclosed is a method of preparing esters of baccatine III or 10-deacetylbaccatine III of formula (I) by esterification of protected baccatine III or 10-deacetylbaccatine III of formula (II) by means of an activated acid of formula (III). The esters of formula (I) can be used to prepare taxane derivatives having remarkable antileucemia and antitumor properties. In formulae (I), (II) and (III) Ar is an aryl radical, R1 is a hydrogen atom or an aryl radical or an R4-O-CO- radical (R4=alkenyl, alkynyl, optionnally substituted alkyl, cycloalkyl, cycloalkynyl, bicycloalkyl, phenyl, heterocyclyle) and R2 is a hydrogen atom, and R3 stands for a hydroxy function protection grouping, or R1 is defined as above and R2 and R3 together form a 5 or 6 membered, saturated heterocyclic ring, G1 is an acetyl radical or a hydroxy function protection grouping, G2 is a hydroxy function protection grouping, and X is an acyl radical, aryl radical or halogen atom. Also disclosed are esters of baccatine III and 10-deacetylbaccatine III, and an intermediate of the formula (III) for this method.