Sodium Carbonate → 4-chloroimidazo[1,2-a]quinoxaline

HRID 1025475Notes

Reaction equation

HRID 1025475 reaction equation
[NH2:1][C:2]1[C:11]([Cl:12])=[N:10][C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]=1.Br[CH2:14][CH:15](OCC)OCC.C(=O)([O-])[O-].[Na+].[Na+]>O.C1COCC1>[Cl:12][C:11]1[C:2]2[N:3]([CH:14]=[CH:15][N:1]=2)[C:4]2[C:9]([N:10]=1)=[CH:8][CH:7]=[CH:6][CH:5]=2

Participants

5

Reactant 3

HCID 10340Sodium CarbonateHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 8172743-Chloroquinoxalin-2-amine

Product 1

HCID 107745254-chloroimidazo[1,2-a]quinoxalineYield 218.2%

Reagents, catalysts & solvents 1

HCID 21881883Oxolane--water (1/1)Solvent

Procedure

To a stirred suspension of 2-amino-3-chloroquinoxaline (25.5 g, 141.8 mmol) in water/THF 1:1 (500 mL), at rt was added 2-bromo-1,1-diethoxyethane (83.8 g, 425.4 mmol) in one portion. After stirring at rt for 1 h, the mixture was heated to reflux for 3 h under stirring and then stirred for an additional 15 h at rt. The pH value of the mixture was adjusted to pH 8 by addition of solid sodium carbonate and the mixture was subsequently extracted with ethyl acetate (3×500 mL) and the combined organic extracts were dried with sodium sulfate. Removal of the solvent yields 4-chloro-imidazo[1,2-a]quinoxaline as an orange-white solid (63 g, 93%): 1H-NMR (300 MHz, d6-DMS): δ=9.05 (d, 1H), 8.51 (dd, 1H), 8.1 (dd, 1H), 7.99 (d, 1H), 7.89 (td, 1H), 7.76 (td, 1H) ppm. UPLC-MS: RT=0.88 min; m/z 204.6 [MH+]; required MW=203.6.

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 3 h
  3. stirringunder stirring
  4. stirringstirred for an additional 15 h at rt
  5. extractionthe mixture was subsequently extracted with ethyl acetate (3×500 mL)
  6. dry with materialthe combined organic extracts were dried with sodium sulfate
  7. customRemoval of the solvent

Sources & evidence

ORD record
ord-cedf7a8413ec406887fb70da68427251
Source dataset
uspto-grants-2014_05
Patent number
US08729082B2

Reaction notes

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