Potassium Carbonate → 6-Bromo-2,3-dimethylimidazo[1,2-a]pyridine

HRID 1943987Notes

Reaction equation

HRID 1943987 reaction equation
Br[CH:2]([CH3:6])[C:3](=O)[CH3:4].[NH2:7][C:8]1[CH:13]=[CH:12][C:11]([Br:14])=[CH:10][N:9]=1.C(=O)([O-])O.[Na+].C(=O)([O-])[O-].[K+].[K+]>C(O)C.O>[Br:14][C:11]1[CH:12]=[CH:13][C:8]2[N:9]([C:2]([CH3:6])=[C:3]([CH3:4])[N:7]=2)[CH:10]=1

Participants

7

Reactant 4

HCID 11430Potassium CarbonateHCID 131422-Butanone, 3-bromo-HCID 706222-Amino-5-bromopyridineHCID 516892Sodium Bicarbonate

Product 1

HCID 145903676-Bromo-2,3-dimethylimidazo[1,2-a]pyridineYield 16.9%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Procedure

13.53 mL (130.06 mmol) of 3-bromobutan-2-one are added to a mixture, stirred at 20° C., of 5 g (28.90 mmol) of 2-amino-5-bromopyridine and 4.85 g (57.80 mmol) of sodium hydrogen carbonate in 100 mL of ethanol. The mixture is refluxed for 12 hours and then concentrated under reduced pressure. The mixture obtained is taken up in 100 mL of water. The pH of the solution is basified by successive additions of potassium carbonate. The mixture is then extracted with 3×50 mL of ethyl acetate. The combined organic phases are washed with water (50 mL), dried over sodium sulfate and then concentrated under reduced pressure. An oil is obtained, which is purified by chromatography on a column of silica, eluting with a mixture of dichloromethane and methanol. 1.1 g of the expected product are thus isolated.

Workup

  1. temperatureThe mixture is refluxed for 12 hours
  2. concentrationconcentrated under reduced pressure
  3. customThe mixture obtained
  4. extractionThe mixture is then extracted with 3×50 mL of ethyl acetate
  5. washThe combined organic phases are washed with water (50 mL)
  6. dry with materialdried over sodium sulfate
  7. concentrationconcentrated under reduced pressure
  8. customAn oil is obtained
  9. customwhich is purified by chromatography on a column of silica
  10. washeluting with a mixture of dichloromethane and methanol

Sources & evidence

ORD record
ord-45ac94157fe94ece9503285807d874bb
Source dataset
uspto-grants-2013_03
Patent number
US08394820B2

Reaction notes

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