Azacyclonol

Azacyclonol
Clinical data
Other names	MER-17; MDL-4829; Diphenylmethanolpiperidine
Routes of; administration	Oral
ATC code	none;
Legal status
Legal status	BR: Class C1 (Other controlled substances); In general: ℞ (Prescription only);
Identifiers
	IUPAC name Diphenyl(piperidin-4-yl)methanol;
CAS Number	115-46-8 ; 1798-50-1 (HCl);
PubChem CID	15723;
ChemSpider	14952 ;
UNII	2MMR990PEM;
ChEMBL	ChEMBL127508 ;
CompTox Dashboard (EPA)	DTXSID2045280 ;
ECHA InfoCard	100.003.720
Chemical and physical data
Formula	C18H21NO
Molar mass	267.372 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES OC(c1ccccc1)(c2ccccc2)C3CCNCC3;
	InChI InChI=1S/C18H21NO/c20-18(15-7-3-1-4-8-15,16-9-5-2-6-10-16)17-11-13-19-14-12-17/h1-10,17,19-20H,11-14H2 ; Key:ZMISODWVFHHWNR-UHFFFAOYSA-N ;
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Azacyclonol (trade names Ataractan, Calmeran, Frenoton, Frenquel, Psychosan), also known as γ-pipradrol, is a drug which is an ataractive; an agent which diminishes hallucinations in psychotic individuals.^[2]^[3] It has also been called a tranquilizer and antipsychotic, though these definitions are not accurate as it does not actually possess such properties. Despite being a positional isomer of pipradrol, it is not a psychostimulant, and instead has mild depressant effects.^[2]^[4]

The drug was introduced in Europe in the mid-1950s for the treatment of schizophrenia likely because it was found to attenuate the subjective psychedelic effects of LSD and mescaline in humans.^[2]^[5] However, due to poor and mixed clinical effectiveness,^[5] it never gained widespread acceptance and was eventually discontinued.

Azacyclonol is also known as diphenylmethanolpiperidine and is the parent structure of the antihistamines fexofenadine and terfenadine. Terfenadine produces azacyclonol as a major active metabolite.^[6]

It is made by the organometallic addition of 4-bromopyridine to benzophenone, followed by catalytic hydrogenation of the pyridine heteroaromatic ring system to the corresponding piperidine.^[7]