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 and the temperature rose to 70° C. After complete addition of the piperidine derivative, the reaction mixture was added to 200 g. of ice, and the aqueous mixture was 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 was removed by evaporation under reduced pressure to provide 44.7 g. of the product as an oil. The oil thus formed was distilled to provide 1-methyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine, B.P. 123°-138° C. at 0.1 torr.

Provenance & Evidence