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)

摘要

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.;