Present invention relates to an improved process for the preparation of Zopiclone and its enantiomerically enriched isomer (Eszopiclone). 6-(5-Chloropyridin-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]pyrazine is reacted with 1-chloro-carbonyl-4-methylpiperazine in the presence of alkali earth metal carbonates, hydroxides or oxides in a solvent medium to give Zopiclone. It is reacted with optically active acid in a mixture of water and water miscible organic solvent followed by work up to give Eszopiclone. The present invention also relates to process for the conversion of (R) or (S) Zopiclone to 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydro-pyrrolo-[3,4-b]-pyrazine of the intermediate which can be converted to racemic Zopiclone.
本发明涉及一种改进的制备Zopiclone及其对映富集异构体(Eszopiclone)的过程。将6-(5-
氯吡啶-2-基)-5-羟基-7-氧代-5,6-二氢
吡咯并[3,4-b]
吡嗪与1-
氯甲酰-4-甲基
哌嗪在碱土
金属
碳酸盐、氢氧化物或氧化物的溶剂介质中反应,得到Zopiclone。它与光学活性酸在
水和
水亲和性有机溶剂的混合物中反应,然后进行后处理,得到Eszopiclone。本发明还涉及将(R)或(S)Zopiclone转化为中间体6-(5-
氯吡啶-2-基)-5-羟基-7-氧代-5,6-二氢
吡咯并[3,4-b]
吡嗪的过程,该中间体可以转化为外消旋Zopiclone。