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

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. To the mixture were added dropwise 10 g of a 37% aqueous hydrochloric acid solution at 10° C., with stirring. When the addition was complete, the whole mixture was stirred at room temperature for 4 hours, after which 20 ml of 18% aqueous hydrochloric acid were then added. The mixture was then heated at 30°-40° C. for 7 hours and allowed to stand overnight at room temperature. The resulting mixture was made alkaline by addition of a 40% aqueous solution of potassium carbonate and, after evaporating off the methanol under reduced pressure, the mixture was extracted with diethyl ether. The ethereal extract was dried over potassium carbonate, after which the diethyl ether was removed. The residue was then distilled under reduced pressure, giving 15.1 g of the title compound as an oil boiling at 91°-93° C./2.0 mmHg.

1. additionWhen the addition
2. stirringthe whole mixture was stirred at room temperature for 4 hours
3. temperatureThe mixture was then heated at 30°-40° C. for 7 hours
4. customafter evaporating off the methanol under reduced pressure
5. extractionthe mixture was extracted with diethyl ether
6. extractionThe ethereal extract
7. dry with materialwas dried over potassium carbonate
8. customafter which the diethyl ether was removed
9. distillationThe residue was then distilled under reduced pressure

ORD record

ord-779d405a13e24094a88e12e748ee8b2d

Source dataset

uspto-grants-1979_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04141883