![6-(5-chloropyridin-2-yl)-7-oxo-6,7-dihydro-5H-pyrrolo[3.4-b]pyrazin-5-yl acetate](/Databaselist/images/loading.webp)
43200-81-3Relevant academic research and scientific papers
Preparation method of zopiclone intermediate
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, (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.
Zopiclone intermediate preparation method
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Paragraph 0023-0025, (2019/01/14)
The invention relates to a zopiclone intermediate preparation method and belongs to the technical field of chemical synthesis. The preparation method includes the steps of firstly, adding 2-formyl pyrazine carboxylic acid shown in the formula V in an alcohols solvent, dropping 2-amino-5-chlorine pyridine shown in the formula VI, performing reflux reaction to obtain the formula III; under stirringof the formula III with acetic anhydride, heating up to reflux reaction to obtain the formula II; under stirring of the formula II with inorganic acid in ethyl alcohol, heating up to reflux reaction.With the preparation method of zopiclone intermediate 6-(5-chlorine pyridine-2-base)-5H-pyrrole(3,4-B)pyrazine05,7(6H)-diketone, the shortcoming about exceeding of open loop impurities and over-reduced impurities due to the fact that an existing process reduction reaction process is hard to control is overcome.
A method for producing zopiclone
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, (2017/01/05)
The invention relates to a preparation method of zopiclone for improving sleeping, belonging to the field of medicines. In the preparation process of 6-(5-chlro-2-pyridyl)-5, 7-dioxo-5, 6-dihydropyrrolo[3, 4-b] pyrazine, namely a compound 3, by taking DMAP (dimethylaminopyridine) as a catalyst, in the presence of triethylamine, cyclization is directly carried out to synthesize an intermediate 3. The crude product yield is 85%, the yield is improved, the operation is simplified, and irritant reagents such as acetic anhydride, thionyl chloride, ethyl chloroformate and the like are not used, thereby facilitating production, facilitating recovery of xylene as a solvent and reducing emission of three wastes. Zopiclone is further synthesized by the compound 3. The method is concise in whole line, simple and convenient to operate and more suitable for industrialized production.
Preparation method of pyrazine hydroxyl pyrrolidone compound
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Paragraph 0040-0043, (2017/02/09)
The present invention discloses a preparation method of a pyrazine hydroxyl pyrrolidone compound. The preparation method comprises the steps of: (a) adjusting the pH value of water to higher than 7 with inorganic base to obtain an aqueous solution of inorganic base, or adjusting the pH value of a water-containing organic solvent to higher than 7 with inorganic base to obtain an inorganic base water-containing organic solvent solution, and dissolving potassium borohydride or sodium borohydride; and (2) dissolving the raw materials in a solvent in a container to obtain a raw material solution, controlling the reaction temperature at 11-15 DEG C, adding a potassium borohydride solution or a sodium borohydride solution, and reacting to obtain the pyrazine hydroxyl pyrrolidone compound. According to the method, potassium borohydride or sodium borohydride is added in the form of solution into the reaction system, and the control of feed rate by temperature indication avoids instantaneous release of excessive hydrogen. The method solves in the problem of instantaneous release of excessive hydrogen due to difficulty in controlling a single dosage in the traditional methods, and has the characteristics of simpleness, safe and reliable production, high yield and good product quality.
Process for synthesis and purification of anhydrous crystalline S-zopiclone
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Page/Page column 9, (2009/06/27)
Process for synthesis and purification of anhydrous crystalline S-zopiclone for the preparation of enantiomerically pure {S)-5-{chloromethyloxycarbonyloxy)-6-{5-chloropyrid-2-yl)-7-oxo-5,6-dihydropyrrolo[3,4b]pyrazine (S)-(I).
Process for Preparation of Dextrorotatory Isomer of 6-(5- chloro-pyrid-2-yl)-5-[(4-methyl -1-piperazinyl) carbonyloxy] -7-oxo-6,7-dihydro-5H-pyrrolo [3,4-b] pyrazine (Eszopiclone)
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Page/Page column 5; 10, (2009/08/16)
Disclosed herein is the process for preparation of 6-(5-chloro-pyrid-2-yl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (Zopiclone), its resolution to get the dextrorotatory isomer of formula (I) substantially free of R(?) enantiomer and recovery of key raw material i.e. 6-(5-chloro pyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]pyrazine from the R-isomer of Zopiclone followed by conversion of the recovered compound to get pure Eszopiclone (I) in high yield and high purity.
PROCESS FOR PREPARATION OF DEXTROROTATORY ISOMER OF 6-(5-CHLORO-PYRID-2-YI)-5-[(4-METHYL -1-PIPERAZINYL) CARBONYLOXY]-7-OXO-6,7-DIHYDRO-5H-PYRROLO [3,4-B] PYRAZINE (ESZOPICLONE)
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Page/Page column 22; 23, (2009/06/27)
Disclosed herein is the process for preparation of 6-(5-chloro-pyrid-2-yl)-5-[(4-methyl-1-piperazinyl) carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo [3,4-b] pyrazine (Zopiclone), its resolution to get the dextrorotatory isomer of formula (I) substantially free of R (-) enantiomer and recovery of key raw material i.e. 6-(5-chloro pyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo [3,4-b] pyrazine from the R-isomer of Zopiclone followed by conversion of the recovered compound to get pure Eszopiclone (I) in high yield and high purity.
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.
Process for the preparation of eszopiclone
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Page/Page column 5, (2008/12/06)
The invention relates to a process for making of 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo-[3,4-b] pyrazin-5-yl-4-methyl piperazine-1-carboxylate, also known as zopiclone. The invention further describes an effective method for resolving of zopiclone into its enantiomers (eszopiclone and (R)-zopiclone) and also provides a method of recycling of (R)-zopiclone.
Enzymatic resolution of new carbonate intermediates for the synthesis of (S)-(+)-zopiclone
Solares, Laura F.,Diaz, Monica,Brieva, Rosario,Sanchez, Victor M.,Bayod, Miguel,Gotor, Vicente
, p. 2577 - 2582 (2007/10/03)
The lipase from Candida antarctica B catalyzes the enantioselective hydrolysis of (±)-6-(5-chloropyridin-2-yl)-7-chloromethyloxycarbonyloxy-6,7- dihydro-5H-pyrrolo[3,4-b]pyrazin-5-one, a useful intermediate in the synthesis of (S)-(+)-zopiclone. This enzyme also catalyzes the resolution of the corresponding 2-chloroethylcarbonate derivative.
