Pirenperone

Pirenperone
Clinical data
Other names	R-47456; R-50656; Pirenpirone
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;

Pirenperone (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, BANTooltip British Approved Name; developmental code names R-47456, 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.

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. 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.

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.