In a process for preparing pentostatin, the improvement wherein reduction is performed on ketone prior to deprotection, comprising:
a) reacting 3-(2-deoxy-3,5-di-O-p-toluoyl-b-D-erythro-pentofuranosyl)-6,7-dihydroimidazol [4,5-d][1,3] diazepin-8 (3H)-one with a ruthenium catalyst formed by the reaction of di-μ-chlorobis[(p-cymene) chlororuthenium (II) and N-(arylsulfonyl)-1,2-diarylethylene diamine in a solvent;
b) stopping the reaction in step a) by making the reaction medium alkaline;
c) separating the mixture from step b) into combined organic layers and washing the reaction product from the combined organic layers with water, filtering, and evaporating solvent to provide a crude product, wherein the ratio of 8R vs 8S isomeric alcohol >100;
d) purifying said crude product by chromatography;
e) deprotecting the keto nucleoside in the crude product in methanol/sodium methoxide to obtain pentostatin; and
f) purifying by recrystallizing pentostatin from methanol to remove inorganic and isomeric impurities.
一种制备戊糖霉素的方法,改进在去保护前对酮进行还原,包括:
a) 在溶剂中用二-μ-
氯化双[(
对二甲苯)
氯合
铑(II)]和N-(芳基磺酰基)-1,2-二芳基
乙二胺反应形成的
钌催化剂与3-(2-脱氧-3,5-二-O-p-
甲苯基-β-D-erythro-戊呋糖基)-6,7-二氢
咪唑[4,5-d][1,3]二氮杂
环己烷-8(3H)-酮反应;
b) 通过使反应介质碱性停止步骤a)中的反应;
c) 将步骤b)中的混合物分离成组合的有机层,并用
水洗涤组合的有机层中的反应产物,过滤并蒸发溶剂以提供粗品,其中8R与8S异构醇的比值>100;
d) 通过色谱法纯化所述粗品;
e) 在
甲醇/甲氧基
钠中去保护粗品中的酮核苷,以获得戊糖霉素;
f) 通过在
甲醇中重结晶戊糖霉素以去除无机和异构杂质。