The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 13, 2012
Filed:
Apr. 10, 2008
OM Dutt Tyagi, Hyderabad, IN;
Tushar Kumar Srivastava, Hyderabad, IN;
Vellanki Siva Ram Prasad, Hyderabad, IN;
Dnyandev Ragho Rane, Hyderabad, IN;
Bandi Naga Durga Rao, Hyderabad, IN;
Daggula Srinivas Reddy, Hyderabad, IN;
Om Dutt Tyagi, Hyderabad, IN;
Tushar Kumar Srivastava, Hyderabad, IN;
Vellanki Siva Ram Prasad, Hyderabad, IN;
Dnyandev Ragho Rane, Hyderabad, IN;
Bandi Naga Durga Rao, Hyderabad, IN;
Daggula Srinivas Reddy, Hyderabad, IN;
Mylan Laboratories Ltd., Hyderabad, IN;
Abstract
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.