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Systematic (IUPAC) name
CAS Number 103255-66-9 YesY
ATC code None
PubChem CID: 59743
ChemSpider 53893 YesY
Chemical data
Formula C25H23ClN4O4
Molecular mass 478.928 g/mol
 YesY (what is this?)  (verify)

Pazinaclone (DN-2327) is a sedative and anxiolytic drug in the cyclopyrrolone family of drugs. Other cyclopyrrolone drugs include zopiclone and eszopiclone.

Pazinaclone has a very similar pharmacological profile to the benzodiazepine family of drugs including sedative and anxiolytic properties, but with less amnestic effects,[1] and at low doses it is a relatively selective anxiolytic, with sedative effects only appearing at higher doses.[2]

Pazinaclone produces its sedative and anxiolytic effects by acting as a partial agonist at GABAA benzodiazepine receptors, although pazinaclone is more subtype-selective than most benzodiazepines.[3]


Pazinaclone synthesis: U.S. Patent 4,778,801

Reaction of 2-Amino-7-chloro-1,8-naphthyridine with phthalic anhydride leads to the corresponding phthalimide. Selective reduction of one of the imide carbonyl groups in essence converts that to an aldehyde. Condensation with tert-Butyl(triphenylphosphoranylidene)acetate gives the Wittig product.

The carboxylic acid is then treated with Diethyl cyanophosphonate to convert that to an activated acid cyanide; reaction with 1,4-Dioxa-8-azaspiro(4.5)decane results in formation of the corresponding amide, pazinaclone.

See also[edit]


  1. ^ Wada T, Fukuda N. Effect of a new anxiolytic, DN-2327, on learning and memory in rats. Pharmacology, Biochemistry and Behavior. 1992 Mar;41(3):573-9.
  2. ^ Suzuki M, Uchiumi M, Murasaki M. A comparative study of the psychological effects of DN-2327, a partial benzodiazepine agonist, and alprazolam. Psychopharmacology (Berlin). 1995 Oct;121(4):442-50.
  3. ^ Atack JR. The benzodiazepine binding site of GABA(A) receptors as a target for the development of novel anxiolytics. Expert Opinion on Investigational Drugs. 2005 May;14(5):601-18.