反应详情

154.7 g of 2,2,6,6-tetramethyl-4-piperidone, 160 g of piperidine and 10.0 g of p-toluenesulphonic acid monohydrate were dissolved in 200 ml of benzene. The solution was refluxed by heating for 8.5 hours, whilst the water formed in situ was removed with a Dean-Stark separator. The reaction mixture was then poured into a mixture comprising 700 ml of water, 200 ml of concentrated aqueous ammonia and 100 g of ice. The organic layer was separated, washed three times with water and then dried over anhydrous magnesium sulphate. After removing the solvent, the residue was distilled under reduced pressure, giving 46.6 g of 1,2,5,6-tetrahydro-2,2,6,6-tetramethyl-4-piperidinopyridine (bp 80° - 82° C/1 mmHg).

1. temperatureThe solution was refluxed
2. customformed in situ
3. customwas removed with a Dean-Stark separator
4. additionThe reaction mixture was then poured into a mixture comprising 700 ml of water, 200 ml of concentrated aqueous ammonia and 100 g of ice
5. customThe organic layer was separated
6. washwashed three times with water
7. dry with materialdried over anhydrous magnesium sulphate
8. customAfter removing the solvent
9. distillationthe residue was distilled under reduced pressure