(-)-Zopiclone; 4-Methyl-(5R)-6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo-[3,4-b]pyrazin-5-yl ester-1-piperazinecarboxylic acid
(-)-Zopiclone; 4-Methyl-(5R)-6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo-[3,4-b]pyrazin-5-yl ester-1-piperazinecarboxylic acid