43200-82-4Relevant articles and documents
Preparation method of zopiclone intermediate
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Paragraph 0024-0064, (2020/06/17)
The invention provides a preparation method of zopiclone. According to the method, anhydride is used as a reaction solvent, pyrazine-2,3-dianhydride and 2-amino-5-chloropyridine are synthesized into 6-(5-chloro-2-pyridyl)-5,7-dioxo-6,7-dihydro-5H-pyrrolo(3,4-b)pyrazine in one step, so that the process is simplified, the obtained product is high in yield and purity, production conditions and environment friendliness are achieved, and the method is suitable for industrial production.
Preparation method for pyrrolo-pyrazine
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Paragraph 0043, (2016/11/09)
The invention discloses a preparation method for pyrrolo-pyrazine. The preparation method comprises the following steps that 1, levo-zopiclone (I) is dissolved into organic solvent, the pH is regulated to 8-10, and heating reflux is performed; 2, water is added, stirring is performed, standing is performed for layering, and a water layer is separated out; 3, the step 2 is repeated; 4, a drying agent is added in an organic layer for drying, filtering is performed, and filtrate is concentrated under reduced pressure until the filtrate is dried into a compound (II); 5, the compound (II) is dissolved into the organic solvent, an oxidizing agent is added, heating reflux oxidation is performed, filtering is performed, filtrate is concentrated under reduced pressure, cooling and crystallizing are performed, filtering is performed, and solids are dried to obtain the pyrrolo-pyrazine (III). According to the method, the by-product levo-zopiclone generated in eszopiclone production can be taken as the raw material to generate the pyrrolo-pyrazine (III) through reacting, the pyrrolo-pyrazine (III) generates zopiclone according to a conventional technique, waste utilization is maximized on the premise that the quality is guaranteed, and discharge of three wastes is greatly reduced.
IMPROVED PROCESS FOR THE PREPARATION OF ZOPICLONE AND IT'S ENANTIOMERICALLY ENRICHED ISOMER
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, (2008/12/08)
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.