Pirenperone

Pirenperone (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, BANTooltip British Approved Name; developmental code names R-47456 and R-50656) is a serotonin receptor antagonist closely related to ketanserin and risperidone which is described as an antipsychotic and tranquilizer and was never marketed.^[2][3]

Other namesR-47456; R-50656; Pirenpirone

Drug classSerotonin 5-HT_2A receptor antagonist

Elimination half-life4–6 hours^[1]

CAS Number

• 75444-65-4

Quick facts Clinical data, Other names ...

Pirenperone

Clinical data
Other names	R-47456; R-50656; Pirenpirone
Drug class	Serotonin 5-HT2A receptor antagonist
Pharmacokinetic data
Elimination half-life	4–6 hours[1]
Identifiers
IUPAC name 3-[2-[4-(4-Fluorobenzoyl)piperidin-1-yl]ethyl]-2-methylpyrido[1,2-a]pyrimidin-4-one
CAS Number	75444-65-4
PubChem CID	4847
ChemSpider	4681
UNII	Y9FMC4513X
KEGG	D05495
ChEBI	CHEBI:92444
ChEMBL	ChEMBL18331
CompTox Dashboard (EPA)	DTXSID9045182
ECHA InfoCard	100.071.081
Chemical and physical data
Formula	C23H24FN3O2
Molar mass	393.462 g·mol−1
3D model (JSmol)	Interactive image
SMILES CC1=C(C(=O)N2C=CC=CC2=N1)CCN3CCC(CC3)C(=O)C4=CC=C(C=C4)F
InChI InChI=1S/C23H24FN3O2/c1-16-20(23(29)27-12-3-2-4-21(27)25-16)11-15-26-13-9-18(10-14-26)22(28)17-5-7-19(24)8-6-17/h2-8,12,18H,9-11,13-15H2,1H3 Key:HXCNRYXBZNHDNE-UHFFFAOYSA-N

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It is a relatively selective antagonist of the serotonin 5-HT_2A receptor and has been used in scientific research to study the serotonin system.^[4][3][5][6] Its affinities (K_i) for serotonin and other receptors have been reported to be 0.3 to 1.1 nM for the serotonin 5-HT_2A receptor, 6.5 nM for the serotonin 5-HT₇ receptor, 20 nM for the α_1B-adrenergic receptor, 20 nM for the α_2B-adrenergic receptor, 61 nM for the serotonin 5-HT_2B receptor, 60 to 77 nM for the serotonin 5-HT_2C receptor, 485 to 1,700 nM for the serotonin 5-HT_1A receptor, and >1,000 or 6,600 nM for the serotonin 5-HT_1B receptor, whereas other receptors were not reported.^[4][6]

The elimination half-life of pirenperone has been said to be 4 to 6 hours.^[1]

In the 1980s, the drug was found to block the effects of the lysergic acid diethylamide (LSD) in animals, and, along with ketanserin, led to the elucidation of the 5-HT_2A receptor as the biological mediator of the effects of serotonergic psychedelics.^[7] Along similar lines, there has been interest in pirenperone for potential use as a trip killer against psychedelics in humans.^[1]