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][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.

[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.