Ocinaplon

Ocinaplon is an anxiolytic drug in the pyrazolopyrimidine family of drugs. Other pyrazolopyrimidine drugs include zaleplon and indiplon.

Ocinaplon

Clinical data
ATC code	none
Identifiers
IUPAC name pyridin-2-yl-(7-pyridin-4-ylpyrazolo[1,5-a]pyrimidin-3-yl)methanone
CAS Number	96604-21-6 Y
PubChem CID	216456
IUPHAR/BPS	4277
ChemSpider	187602 Y
UNII	2H6KVC5E76
KEGG	D02617 Y
CompTox Dashboard (EPA)	DTXSID00242362
Chemical and physical data
Formula	C17H11N5O
Molar mass	301.309 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C(c1cnn2c(ccnc12)c3ccncc3)c4ncccc4
InChI InChI=1S/C17H11N5O/c23-16(14-3-1-2-7-19-14)13-11-21-22-15(6-10-20-17(13)22)12-4-8-18-9-5-12/h1-11H Y Key:OQJFBUOFGHPMSR-UHFFFAOYSA-N Y
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Ocinaplon has a similar pharmacological profile to the benzodiazepine family of drugs, but with mainly anxiolytic properties and relatively little sedative or amnestic effect.^[1]

Medical uses

A 2019 review found tentative evidence of benefit in anxiety.^[2]

Mechanism of action

The mechanism of action by which ocinaplon produces its anxiolytic effects is by modulating GABA_A receptors,^[3] although ocinaplon is more subtype-selective than most benzodiazepines.^[4]

Availability

Development of ocinaplon is discontinued due to liver complications that occurred in one of the Phase III subjects.^[5]

Synthesis

Ocinaplon synthesis: U.S. patent 4,521,422 Further reading:^[6][7]

Condensation of 4-Acetylpyridine^[8] with N,N-Dimethylformamide dimethyl acetal (DMFDMA) gives the "enamide" (3). This is then condensed with (3-Amino-1H-pyrazol-4-yl)(2-pyridinyl)methanone (4) (96219-90-8).^[9][10] This is the same intermediate as was used in the synthesis of zaleplon in which the nitrile is replaced by a 2-acetylpyridil moiety. This affords the anxiolytic agent ocinaplon (5).