Water → 2,2,6,6-Tetramethyl-4-(piperidin-1-yl)-1,2,3,6-tetrahydropyridine

HRID 839998Notes

Reaction equation

HRID 839998 reaction equation
[CH3:1][C:2]1([CH3:11])[CH2:7][C:6](=O)[CH2:5][C:4]([CH3:10])([CH3:9])[NH:3]1.[NH:12]1[CH2:17][CH2:16][CH2:15][CH2:14][CH2:13]1.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.O>C1C=CC=CC=1>[CH3:1][C:2]1([CH3:11])[CH:7]=[C:6]([N:12]2[CH2:17][CH2:16][CH2:15][CH2:14][CH2:13]2)[CH2:5][C:4]([CH3:10])([CH3:9])[NH:3]1

Participants

6

Reactant 4

HCID 962WaterHCID 8082PiperidineHCID 132202,2,6,6-Tetramethyl-4-piperidoneHCID 521998p-Toluenesulfonic acid monohydrate

Product 1

HCID 125926662,2,6,6-Tetramethyl-4-(piperidin-1-yl)-1,2,3,6-tetrahydropyridineYield 21%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

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 by means of a Dean-Stark separator. The reaction mixture was then poured into a mixture of 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 magnesium sulphate. After removal of 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).

Workup

  1. temperatureThe solution was refluxed
  2. customformed in situ
  3. customwas removed by means of a Dean-Stark separator
  4. additionThe reaction mixture was then poured into a mixture of 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 magnesium sulphate
  8. customAfter removal of the solvent
  9. distillationthe residue was distilled under reduced pressure

Sources & evidence

ORD record
ord-1304655af0694a5a94c8c924ec579d5e
Source dataset
uspto-grants-1978_06
Patent number
US04097587

Reaction notes

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