Piperidine → 1-Methyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine

Participants

Reaction Steps

To a stirred solution of 200 ml. of 50 g. of phosphorous pentoxide in methanesulfonic acid was added portionwise over four minutes 59 g. of 1-methyl-4-hydroxy-4-(3-hydroxyphenyl)piperidine. The reaction was exothermic, the temperature rising to 70° C. After complete addition of the piperidine derivative, the reaction mixture was poured onto 200 g. of ice, and the resulting aqueous mixture made alkaline by the addition of ammonium hydroxide. The alkaline mixture was extracted several times with diethyl ether, and the ethereal extracts were combined, washed with water, dried, and the solvent removed by evaporation under reduced pressure to provide 44.7 g. of an oil. The oil was distilled to provide 1-methyl-4-(3-methoxyphenyl)-1,2,5,6-tetrahydropyridine; B.P.=123°-138° C. at 0.1 torr.

Provenance & Evidence