1-Piperazinecarboxylic acid, 4-methyl-, 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo(3,4-b)pyrazin-5-yl ester, 4-oxide 43200-96-0 6-(5-Chloro-2-pyridyl)-7-((4-oxo-4-methyl-1-piperazinyl)carbonyloxy)-6,7-dihydro(5H)pyrrolo(3,4-b)pyrazin-5-one N-Oxidezopiclone OXZOP Zopiclone N-oxide