p-Toluenesulfonic acid → 5,5-Dimethoxypiperidin-2-one

HRID 1586559Notes

Reaction equation

HRID 1586559 reaction equation
[C:1]1(C)C=CC(S(O)(=O)=O)=CC=1.[CH:12]([O-:16])([O-])[O:13][CH3:14].[NH:17]1[CH2:22]C(=O)[CH2:20][CH2:19][C:18]1=[O:24].C(N(CC)CC)C>CO>[CH3:1][O:16][C:12]1([O:13][CH3:14])[CH2:22][NH:17][C:18](=[O:24])[CH2:19][CH2:20]1

Participants

6

Reactant 4

HCID 6101p-Toluenesulfonic acidHCID 8471TriethylamineHCID 5339302,5-PiperidinedioneHCID 53629101Methylorthoformate

Product 1

HCID 117449065,5-Dimethoxypiperidin-2-one

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

About 5 mg of p-toluenesulfonic acid was added to a solution of methyl orthoformate (5 ml), and the resulting mixture was then added to a solution of 2,5-piperidinedione (1.8 g, 16 mmol) in methanol (20 ml). The mixture was heated under reflux for 12 hours. After cooling, triethylamine (1 ml) was added to the mixture, and then the mixture was concentrated by using a rotary evaporator. The residue was purified by silica gel column chromatography (CHCl3 :MeOH=15:1), and then recrystallized from ethyl acetate/ether to obtain 5,5-dimethoxy-2-piperidone as the desired compound (1.85 g, 81%). m.p. 89-90° C.; 1H-NMR (CDCl3, 300 MHz) δ: 2.01 (t, 2H, J=7.0 Hz, NCOCH2 --), 2.43 (t, 2H, J=7.0 Hz, NCOCH2CH2 --), 3.25 (s, 6H, OMe), 3.36 (d, 2H, J=2.5 Hz, NCH2C(OMe)2), 5.89 (bs, 1H, NH). P-SIMS (Glycerin matrix) 182 (M+ +1.8%), 160 (100%), 128 (34%), 101 (5%).

Workup

  1. temperatureThe mixture was heated
  2. temperatureunder reflux for 12 hours
  3. temperatureAfter cooling
  4. concentrationthe mixture was concentrated
  5. customa rotary evaporator
  6. customThe residue was purified by silica gel column chromatography (CHCl3 :MeOH=15:1)
  7. customrecrystallized from ethyl acetate/ether

Sources & evidence

ORD record
ord-a23d066e10e94797878ab518c6e673ae
Source dataset
uspto-grants-1999_08
Patent number
US05945564

Reaction notes

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