Title: Zopiclone
CAS Registry Number: 43200-80-2
CAS Name: 4-Methyl-1-piperazinecarboxylic acid 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo[3,4-b]pyrazin-5-yl ester
Additional Names: 6-(5-chloropyrid-2-yl)-5-(4-methylpiperazin-1-yl)carbonyloxy-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine
Manufacturers' Codes: RP-27267
Trademarks: Amoban (Aventis); Imovane (Aventis); Limovan (Aventis); Sopivan (Aventis); Ximovan (Aventis); Zimovane (Aventis)
Molecular Formula: C17H17ClN6O3
Molecular Weight: 388.81
Percent Composition: C 52.51%, H 4.41%, Cl 9.12%, N 21.61%, O 12.34%
Literature References: Cyclopyrrolone member of a family of non-benzodiazepine GABAA receptor agonists. Prepn: C. Cotrel et al., DE 2300491; eidem, US 3862149 (1973, 1975 both to Rhone-Poulenc); C. Jeanmart, C. Cotrel, C.R. Seances Acad. Sci. Ser. C 287, 377 (1978). In vitro and in vivo inhibition of benzodiazepine binding: J. C. Blanchard et al., Life Sci. 24, 2417 (1979); see also P. H. Wu et al., ibid. 28, 1023 (1981). Comparative study with benzodiazepines: E. Wickström, K. E. Giercksky, Eur. J. Clin. Pharmacol. 17, 93 (1980). HPLC determn of enantiomers in plasma: C. Fernandez et al., J. Chromatogr.572, 195 (1991); in urine: eidem, ibid. 617, 271 (1993). Pharmacokinetics of zopiclone and enantiomers: eidem, Drug Metab. Dispos. 21, 1125 (1993). Mechanism of action: A. Doble et al., Eur. Psychiatr. 10, Suppl 3, 117s (1995). Sedative and anxiolytic effects of enantiomers and metabolite in rats: J. N. Carlson et al., Eur. J. Pharmacol. 415, 181 (2001). Series of articles on pharmacokinetics, pharmacology and efficacy in insomnia: Sleep 10, Suppl 1, 1-87 (1987). Clinical overview: B. Musch, F. Maillard, Int. J. Clin. Psychopharmacol. 5, 147-158 (1990). Review of pharmacology, tolerability and therapeutic efficacy: S. Noble et al., Drugs 55, 277-302 (1998).
Properties: Crystals from acetonitrile/diisopropyl ether (1:1), mp 178°.
Melting point: mp 178°
Derivative Type: S-Form
CAS Registry Number: 138729-47-2
Additional Names: Eszopiclone
Trademarks: Estorra (Sepracor); Lunesta (Sepracor)
Literature References: Prepn: C. Cotrel, G. Roussel, WO 9212980 (1992 to Rhone-Poulenc Rorer); see also: eidem, US 6319926 (2001 to Sepracor).
Properties: Crystals from acetonitrile, mp 206.5°. [a]D20 +135 ±3° (c = 1.0 in acetone).
Melting point: mp 206.5°
Optical Rotation: [a]D20 +135 ±3° (c = 1.0 in acetone)
NOTE: This is a controlled substance (depressant): 21 CFR, 1308.14.
Therap-Cat: Sedative, hypnotic.
Keywords: Sedative/Hypnotic.
Zopolrestat Zosuquidar Zotepine Zoxamide Zoxazolamine

Zopiclone ball-and-stick.png
Systematic (IUPAC) name
(RS)-6-(5-chloropyridin-2-yl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl 4-methylpiperazine-1-carboxylate
Clinical data
Trade names Imovane, Zimovane
AHFS/Drugs.com International Drug Names
Pregnancy cat. C (AU) C (US)
Legal status Prescription Only (S4) (AU) POM (UK) Schedule IV (US)
Routes Oral tablets, 3.75mg (UK), 5 or 7.5 mg
Pharmacokinetic data
Bioavailability 52-59% bound to plasma protein
Metabolism Various cytochrome P450 liver enzymes
Half-life ~6 hours
~9 hours for over 65
Excretion Urine
CAS number 43200-80-2 YesY
ATC code N05CF01
PubChem CID 5735
DrugBank DB01198
ChemSpider 5533 YesY
KEGG D01372 YesY
ChEBI CHEBI:32315 YesY
Chemical data
Formula C17H17ClN6O3 
Mol. mass 388.808 g/mol
 YesY (what is this?)  (verify)

Zopiclone (brand name Imovane in Canada, Australia, Sweden, Finland, Norway, Russia and the United Kingdom, brand name Zimovane in Europe) is a nonbenzodiazepine hypnotic agent used in the treatment of insomnia. It is a cyclopyrrolone, which increases the normal transmission of the signal substance GABA in the central nervous system, as benzodiazepines do, but in a different way.

As zopiclone is sedating it is marketed as a sleeping pill. It works by causing a depression or tranquilization of the central nervous system. After prolonged use the body can become accustomed to the effects of zopiclone. When the dose is then reduced or the drug is stopped, withdrawal symptoms may result. These can include a range of symptoms similar to those of benzodiazepine withdrawal.

In the United States, zopiclone is not commercially available,[1] although its active stereoisomer, eszopiclone, is sold under the name Lunesta (see History). Zopiclone is a controlled substance in the United States, Japan, Brazil, and some European countries, and may be illegal to possess without a prescription.

Zopiclone is known colloquially as a "Z-drug." Other Z-drugs include zaleplon (Sonata) and zolpidem (Ambien and AmbienCR) and were initially thought to be less addictive and/or habit forming than benzodiazepines. However, this appraisal has shifted somewhat in the last few years as cases of addiction and habituation have been presented. It is recommended that zopiclone be taken on a short-term basis, usually a week or less.[2] Daily or continuous use of the drug is not usually advised.[3]