Methyl iodide → 1,3,3-Trimethyl-1,2,3,4-tetrahydroquinoxalin-2-one

HRID 990961Notes

Reaction equation

HRID 990961 reaction equation
[CH3:1][C:2]1([CH3:13])[NH:11][C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:12].[H-].[Na+].I[CH3:17]>C1COCC1>[CH3:17][N:4]1[C:5]2[C:10](=[CH:9][CH:8]=[CH:7][CH:6]=2)[NH:11][C:2]([CH3:13])([CH3:1])[C:3]1=[O:12]

Participants

5

Reactant 3

HCID 6328Methyl iodideHCID 24758Sodium hydrideHCID 5952033,3-Dimethyl-1,2,3,4-tetrahydroquinoxalin-2-one

Product 1

HCID 31313661,3,3-Trimethyl-1,2,3,4-tetrahydroquinoxalin-2-oneYield 78%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

In a 200-mL r.b. flask, a solution of 3,4-dihydro-3,3-dimethylquinoxalin-2(1H)-one (1.00 g, 5.66 mmol) in dry THF was treated with NaH (0.28 g, 7.09 mmol, 1.25 equiv). The reaction mixture was stirred at room temperature for 30 minutes before iodomethane (0.39 mL, 6.24 mmol, 1.1 equiv) was added to the reaction flask. The reaction was then stirred at room temperature overnight then partitioned between EtOAc (100 mL) and H2O (20 mL). The aqueous layer was extracted with EtOAc (2×30 mL). The combined organic layers were then washed with brine (20 mL), dried (MgSO4), filtered, and concentrated to a thick oil. Purification by flash chromatography (25% EtOAc/hexane) afforded 830 mg (78%) of 3,4-dihydro-1,3,3-trimethylquinoxalin-2(1H)-one as a white solid. Data for 3,4-dihydro-1,3,3-trimethylquinoxalin-2(1H)-one: 1H NMR (400 MHz, CDCl3) δ 6.90 (m, 3H), 6.67 (d, J=7.7, 1H), 3.69 (bs, 1H), 3.36 (s, 3H), 1.37 (s, 6H).

Workup

  1. additionwas added to the reaction flask
  2. customthen partitioned between EtOAc (100 mL) and H2O (20 mL)
  3. extractionThe aqueous layer was extracted with EtOAc (2×30 mL)
  4. washThe combined organic layers were then washed with brine (20 mL)
  5. dry with materialdried (MgSO4)
  6. filtrationfiltered
  7. concentrationconcentrated to a thick oil
  8. customPurification by flash chromatography (25% EtOAc/hexane)

Sources & evidence

ORD record
ord-968a8efdefed425b978b82bbef959153
Source dataset
uspto-grants-2002_10
Patent number
US06462038B1

Reaction notes

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