The present invention provides a process for the preparation of a citric acid salt of a compound of formula II:
wherein R1 and R2 have the meanings given in the specification, comprising the steps of:
(i) allowing a compound of formula III, described herein, to react with a compound of formula IV, described herein, in the presence of a metal carbonate and wherein said process is characterized by the use of water as solvent, excluding mixtures of water and organic solvents; to form a compound of formula I, described herein;
(ii) reacting the compound of formula I as formed in step (i) with an acyl chloride or hydrochloric acid dissolved in an aqueous alkanol;
(iii) reacting the hydrochloride salt of the compound of formula I formed in step (ii) in the presence of a base in a suitable solvent with a compound of formula V, described herein, to form the compound of formula II; and
(iv) mixing the compound of formula II and citric acid in a suitable solvent to form a citric acid salt.
本发明提供了一种制备式 II 化合物
柠檬酸盐的工艺:
其中 R1 和 R2 具有说明书中给出的含义,包括以下步骤
(i) 使本文所述的式 III 化合物在
金属
碳酸盐存在下与本文所述的式 IV 化合物反应,其中所述 工艺的特征在于使用
水作为溶剂,不包括
水和有机溶剂的混合物;以形成本文所述的式 I 化合物;
(ii) 将步骤(i)中形成的式 I 化合物与溶解在烷醇
水溶液中的酰基
氯或
盐酸反应;
(iii) 在碱存在下,在适当溶剂中使步骤(ii)中形成的式 I 化合物盐酸盐与本文所述的式 V 化合物反应,形成式 II 化合物;以及
(iv) 将式 II 化合物和
柠檬酸在合适的溶剂中混合,形成
柠檬酸盐。