Hydrochloric Acid → 2,6-Diethyl-2,3,6-trimethylpiperidin-4-one

Participants

Reaction Conditions

Reaction Steps

19.6 g of 2,4,6-triethyl-2,6-dimethyl-1,2,5,6-tetrahydropyrimidine and 0.4 g of ammonium bromide were added to 200 ml of methanol. Whilst maintaining the mixture at 10° C and stirring, 10 g of 37% hydrochloric acid were added dropwise. After completion of the addition, the resulting mixture was stirred at room temperature for 4 hours and there were then added dropwise 20 ml of 18% hydrochloric acid. The mixture was then heated at 30°-40° C for 7 hours and allowed to stand overnight at room temperature. After this, the mixture was made alkaline by the addition of a 40% aqueous solution of potassium carbonate, the methanol was evaporated off under reduced pressure, and the mixture was extracted with diethyl ether. The ethereal solution was dried over potassium carbonate and the diethyl ether was then removed. The residue was distilled under reduced pressure, giving 15.1 g of 2,6-diethyl-2,3,6-trimethyl-4-piperidone as an oil boiling at 91° - 93° C/2.0 mmHg.

Provenance & Evidence