Clinical data
ATC code
  • none
  • 2-(7-chloro-1,8-naphthyridin-2-yl)-3-[2-(1,4-dioxa-8-azaspiro[4.5]decan-8-yl)-2-oxoethyl]-3H-isoindol-1-one
CAS Number
PubChem CID
Chemical and physical data
Molar mass478.93 g·mol−1
3D model (JSmol)
  • Clc1nc2nc(ccc2cc1)N4C(=O)c3ccccc3C4CC(=O)N6CCC5(OCCO5)CC6
  • InChI=1S/C25H23ClN4O4/c26-20-7-5-16-6-8-21(28-23(16)27-20)30-19(17-3-1-2-4-18(17)24(30)32)15-22(31)29-11-9-25(10-12-29)33-13-14-34-25/h1-8,19H,9-15H2 checkY

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

Pazinaclone has a very similar pharmacological profile to the benzodiazepines 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
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


  1. ^ Wada T, Fukuda N (March 1992). "Effect of a new anxiolytic, DN-2327, on learning and memory in rats". Pharmacology, Biochemistry, and Behavior. 41 (3): 573–9. doi:10.1016/0091-3057(92)90375-p. PMID 1350101. S2CID 20581568.
  2. ^ Suzuki M, Uchiumi M, Murasaki M (October 1995). "A comparative study of the psychological effects of DN-2327, a partial benzodiazepine agonist, and alprazolam". Psychopharmacology. 121 (4): 442–50. doi:10.1007/BF02246492. PMID 8619007. S2CID 35222663.
  3. ^ Atack JR (May 2005). "The benzodiazepine binding site of GABA(A) receptors as a target for the development of novel anxiolytics". Expert Opinion on Investigational Drugs. 14 (5): 601–18. doi:10.1517/13543784.14.5.601. PMID 15926867. S2CID 22793644.