Pazinaclone

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

Pazinaclone

Clinical data
ATC code	none
Identifiers
IUPAC name 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	103255-66-9 Y
PubChem CID	59743
ChemSpider	53893 Y
UNII	MHK03047IJ
KEGG	D05378 Y
ChEMBL	ChEMBL2107504 Y
CompTox Dashboard (EPA)	DTXSID70869388
Chemical and physical data
Formula	C25H23ClN4O4
Molar mass	478.93 g·mol−1
3D model (JSmol)	Interactive image
SMILES Clc1nc2nc(ccc2cc1)N4C(=O)c3ccccc3C4CC(=O)N6CCC5(OCCO5)CC6
InChI 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 Y Key:DPGKFACWOCLTCA-UHFFFAOYSA-N Y
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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 GABA_A benzodiazepine receptors, although pazinaclone is more subtype-selective than most benzodiazepines.^[3]

Synthesis

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

• Pagoclone