A process for the preparation of taxanes comprising
##STR1##
wherein R is a tert. butoxycarbonyl or benzoyl group; PMP is p-methoxyphenyl
group; G1 is acetyl group; G2 is haloacetyl group comprising
- a) protecting the C-7 hydroxyl group of 10-deacetylbaccatin III with
haloacetyl chlorides and then acetylating the C-10 hydroxyl group with acetyl chloride
to obtain a protected 10-deacetylbaccatin III (1);
- b) subjecting the protected 10-deacetylbaccatin III (1) to coupling
with an oxazolidine-5-caboxylic acid of formula 2
##STR2##
wherein R is tert. butoxycarbonyl or benzoyl; PMP is p-methoxyphenyl group
in the presence of a condensation agent and an activating agent to obtain C-13
esters of formula 3;
- c) treating the coupled products 3 with weak acidic medium to open the
oxazolidine ring to obtain intermediates of formula 4;
##STR3##
wherein R is a tert. butoxycarbonyl or benzoyl group; G1 is acetyl
group; G2 is haloacetyl group
- d) subjecting the intermediates of compound 4 to selective deprotection
of haloacyl group in the presence of acetyl group under mild alkaline condition
at -20 to +40 C. for 6-24 h in the presence of ammonia or aliphatic amine
or aromatic amines or their combination to obtain paclitaxel or docetaxel.
