[(7S)-6-(5-chloropyridin-2-yl)-5-oxo-7H-pyrrolo[3,4-b]pyrazin-7-yl] 2,2,3,3,5,5,6,6-octadeuterio-4-methylpiperazine-1-carboxylate; 1-Piperazine-2,2,3,3,5,5,6,6-d8-carboxylic acid, 4-methyl-, (5S)-6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo[3,4-b]pyrazin-5-yl ester;(+)-Eszopiclone-D8;(+)-Zopiclone-D8;(S)-Eszopiclone-D8;(S)-Zopiclone-D8;1-Piperazinecarboxylic acid, 4-methyl-, 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo[3,4-b]pyrazin-5-yl ester, (S)--D8;5H-Pyrrolo[3,4-b]pyrazine, 1-piperazinecarboxylic acid deriv.-D8;[(7S)-6-(5-Chloropyridin-2-yl)-5-oxo-7H-pyrrolo[3,4-b]pyrazin-7-yl] 4-methylpiperazine-1-carboxylate-D8;Esopiclone-D8;Estorra-D8;Eszopiclone-D8;Lunesta-D8;