This invention relates to a process for preparation of taxanes comprising
subjecting 7,10-diprotected intermediates 7-O-(2-haloacyl)baccatin III 6c
or 7,10-O-di-(2-haloacyl)-10-deacetylbaccatin III 6b to a step of
coupling with
(4S,5R)-3-[(2-alkyl/aryl-2-trialkylsilyl)ethoxy-carbonyl]-4-aryl-2-substi-
tuted-1,3-oxazolidine-5-carboxylic acid 1 in the presence of a
condensation agent, an activating agent and an aromatic hydrocarbon to
obtain 7-O-[2-(haloacyl)]-13-[(4S,5R)-4-aryl-2-substituted-3(2-unsubstitu-
ted/substituted-2-trialkylsilyl)-ethoxycarbonyl-1,3-oxazolidinyl-5-carbony-
l]baccatin III 7a or
7,10-di-O[2-(haloacyl)]-13-[(4S,5R)-4-aryl-2-substituted-3-(2-unsubstitut-
ed/substituted-2-trialkylsilyl)ethoxy-carbonyl-1,3-oxazolidinyl-5-carbonyl-
]-10-deacetylbaccatin III 7b; treating the coupled products
7-O-[2-(haloacyl)]-13-[(4S,5R)-4-aryl-2-substituted-3-(2-substituted-2-tr-
ialkylsilyl)ethoxy-carbonyl-1,3-oxazolidinyl-5-carbonyl]baccatin III 7a or
7,10-di-O-[2[(haloacyl)]-13-[(4S,5R)-4-aryl-2-substituted-3-(2-substitute-
d-2-trialkylsilyl)ethoxycarbonyl-1,3-oxazolidinyl-5-carbonyl]-10-deacetylb-
accatin III 7b with tetraalkylammonium halide in a haloalkane to obtain
free amine of structure 8; treating free amine 8 with acid chloride or
acid anhydride in the presence of a base in a heterogeneous phase to
obtain the intermediates of structure 9; subjecting the intermediates of
compound 9 to the deprotection of 2-haloacyl group under mild alkaline
condition at -20 to +40.degree. C. for 6 24 h in the presence of ammonia
or aliphatic amines or aromatic amines or their combination to obtain
paclitaxel or docetaxel.