A process for the preparation of taxanes comprising
1
wherein R is a tert. butoxycarbonyl or benzoyl group; PMP is p-methoxyphenyl group; G
1
is acetyl group; G
2
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
2
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;
3
wherein R is a tert. butoxycarbonyl or benzoyl group; G
1
is acetyl group; G
2
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 6-24h in the presence of ammonia or aliphatic amine or aromatic amines or their combination to obtain paclitaxel or docetaxel.
一种制备
紫杉醇的方法,其中R为叔丁氧羰基或苯甲酰基;
PMP为对
甲氧基苯基;G1为乙酰基;G2为含卤代的乙酰基,包括以下步骤:
a) 用卤代
乙酰氯保护10-去乙酰
紫杉醇III的C-7羟基,然后用
乙酰氯使C-10羟基乙酰化,得到保护的10-去乙酰
紫杉醇III(1);
b) 在
缩合剂和活化剂的存在下,将保护的10-去乙酰
紫杉醇III(1)与式22的
噁唑烷-5-
羧酸R为叔丁氧羰基或苯甲酰基,
PMP为对
甲氧基苯基偶联,得到式3的C-13酯;
c) 用弱酸性介质处理偶联产物3,打开
噁唑烷环,得到式4的中间体;
d) 在
氨水或脂肪胺或芳香胺或它们的组合物的存在下,在温度为-20至+40℃的温和碱性条件下,选择性去除中间体4中的卤代乙酰基,得到
紫杉醇或
多西他赛。