Sulfuric Acid → Ethyl 8-bromo-6-chloroimidazo[1,2-a]pyridine-3-carboxylate

HRID 931019Notes

Reaction equation

HRID 931019 reaction equation
[Br:1][C:2]1[C:3]([NH2:9])=[N:4][CH:5]=[C:6]([Cl:8])[CH:7]=1.Cl[C:11]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:12][O-].[K+].S(=O)(=O)(O)O>C(O)C>[Br:1][C:2]1[C:3]2[N:4]([C:11]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:12][N:9]=2)[CH:5]=[C:6]([Cl:8])[CH:7]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 27639713-Bromo-5-chloropyridin-2-amineHCID 74089075Potassium 2-chloro-3-ethoxy-3-oxoprop-1-en-1-olate

Product 1

HCID 118378994Ethyl 8-bromo-6-chloroimidazo[1,2-a]pyridine-3-carboxylateYield 57.4%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 3-bromo-5-chloropyridin-2-amine (1.0 g), potassium 2-chloro-3-ethoxy-3-oxoprop-1-en-1-olate (2.27 g), sulfuric acid (0.334 mL) and ethanol (20 mL) was heated with reflux overnight. The solvent was evaporated under reduced pressure, the residue was neutralized with saturated aqueous sodium bicarbonate solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane), and the obtained solid was recrystallized from ethyl acetate/hexane to give the title compound (0.84 g).

Workup

  1. temperaturewas heated
  2. temperaturewith reflux overnight
  3. customThe solvent was evaporated under reduced pressure
  4. extractionthe mixture was extracted with ethyl acetate
  5. washThe organic layer was washed with water and saturated brine
  6. dry with materialdried over anhydrous magnesium sulfate
  7. customthe solvent was evaporated under reduced pressure
  8. customThe residue was purified by silica gel column chromatography (ethyl acetate/hexane)
  9. customthe obtained solid was recrystallized from ethyl acetate/hexane

Sources & evidence

ORD record
ord-9b39ab2b6ee84de1b9b05caea2c1f1e5
Source dataset
uspto-grants-2016_03
Patent number
US09296746B2

Reaction notes

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