144-11-6

Artane,Lederle,US,1949

Anticholinergic; antiparkinsonian.

Trihexyphenidyl, an antiparkinsonian drug, possesses central and peripheral anticholinergic actions, as well as a direct relaxant effect on smooth muscle. It reduces muscle rigidity and general stiffness, and has a relatively minor effect on tremors. It is used in Parkinsonism in the form of monotherapy as well as in combination with levodopa.

ChEBI: Trihexyphenidyl is an amine.

Acetophenone, paraformaldehyde and piperidine are first reacted to give ω-(1- piperidyl)propiophenone. To an absolute ethyl ether solution of cyclohexylmagnesium bromide (prepared from 261 parts of cyclohexyl bromide, 38.8 parts magnesium turnings and 700 parts by volume absolute ethyl ether) a dry solution of 174 parts omega-(1-piperidyl)-propiophenonein 600 parts by volume of ether is added, with stirring, at such a rate that gentle reflux is maintained with no external cooling or heating. The reaction mixture is stirred for about 5 hours and then allowed to stand at room temperature until reaction appears complete. While being cooled the reaction mixture is then decomposed by the dropwise addition of 500 parts by volume of 2.5 N hydrochloric acid, and finally is made strongly acidic to Congo red by the addition of concentrated hydrochloric acid.
The resulting white solid is collected on a filter, air dried, redissolved in 2,500 parts water at 95°C and the resulting solution treated with decolorizing charcoal and clarified by filtration. The cooled filtrate is made alkaline with ammonia and the product, crude 3-(1-piperidyl)-1-cyclohexyl-1-phenyl-1- propanol is collected. The hydrochloride melts with decomposition in ten seconds in a bath held at 258.5°C. The alcohol melts at 114.3° to 115.0°C, according to US Patent 2,716,121.

Artane (Lederle); Tremin (Schering).

Antiparkinsonian

Poison by intraperitoneal, subcutaneous, and intravenous routes. When heated to decomposition it emits toxic fumes of NOx.

Trihexyphenidyl, 1-cyclohexyl-1-phenyl-3-piperidineopropan-1-ol (10.2.2), is synthesized by the reaction of 2-(1-piperidino)propiophenone (10.2.1) with cyclohexylmagnesiumbromide. The initial 2-(1-piperidino)propiophenone is synthesized in turn by the aminomethylation of benzophenone using paraformaldehyde and piperidine [24¨C27].