The invention relates to an eszopiclone preparation method comprising main steps that: zopiclone is subjected to a reaction with D-dibenzoyltartaric acid or a hydrate thereof, such that dextral zopiclone-D-dibenzoyltartrate is produced; and the salt is dissociated, such that eszopiclone is obtained. According to the method, D-dibenzoyltartaric acid with a substance amount of a quarter to a half of that of zopiclone is adopted. The reaction conditions are mild, operation is convenient, product yield is high, and product purity is high. The method is suitable for large-scale industrialized productions.
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Paragraph 0038; 0039; 0049; 0050
(2017/05/05)
PROCESS FOR RESOLVING ZOPICLONE
The present invention provides a process for the preparation of the dextrorotatory isomer of zopiclone (eszopiclone). The present invention also provides eszopiclone di-p-anisolyl-L-tartrate and eszopiclone diacetyl-L-tartrate, which are useful as intermediates in a process for preparing eszopiclone.
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Page/Page column 10
(2010/06/11)
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)
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.
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Page/Page column 20; 21
(2009/06/27)
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)
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.
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Page/Page column 5; 9
(2009/08/16)
IMPROVED PROCESS FOR THE PREPARATION OF ZOPICLONE AND IT'S ENANTIOMERICALLY ENRICHED ISOMER
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.
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(2008/12/08)
Process for the preparation of eszopiclone
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.
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Page/Page column 5
(2008/12/06)
More Articles about upstream products of 144025-94-5
Get Best Price for144025-94-5(R)-6-(5-chloropyridin-2-yl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4b]pyrazin-5-yl 4-methylpiperazine-1-carboxylate D-(+)-O,O'-dibenzoyltartaric acid salt