Sulfuric Acid → Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

HRID 335308Notes

Reaction equation

HRID 335308 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([NH2:8])[CH:3]=1.Cl/[C:10](/[CH:16]=O)=[C:11](\[O:13][CH2:14][CH3:15])/[O-:12].[K+].S(=O)(=O)(O)O>C(O)C>[Br:1][C:2]1[CH:7]=[CH:6][N:5]2[C:10]([C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:16][N:8]=[C:4]2[CH:3]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 6932822-Amino-4-bromopyridineHCID 86695681Potassium (Z)-2-chloro-1-ethoxy-3-oxoprop-1-en-1-olate

Product 1

HCID 67260906Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Conditions

Temperature
90 °C

Procedure

A solution of 4-bromopyridin-2-amine (10 g, 57.8 mmol) and potassium (Z)-2-chloro-1-ethoxy-3-oxoprop-1-en-1-olate (step 1) (23.4 g, 124 mmol) in ethanol (200 ml) was cooled to 5° C. Sulfuric acid (7.70 ml, 144 mmol) was added dropwise and the reaction heated to reflux at 90° C. for 3 hrs. The mixture was cooled to RT and TEA (20.03 ml, 144 mmol) was slowly added and heating continued at 90° C. for 18 hrs. After cooling to RT, the mixture was filtered and the solid was partitioned between EtOAc and aqueous 2M HCl. The aqueous layer was basified (NaOH, solid pellets) and extracted using EtOAc. The combined organic extracts were dried (MgSO4) and concentrated in vacuo to afford the title compound;

Workup

  1. temperaturethe reaction heated
  2. temperatureThe mixture was cooled to RT
  3. temperatureheating
  4. temperatureAfter cooling to RT
  5. filtrationthe mixture was filtered
  6. customthe solid was partitioned between EtOAc and aqueous 2M HCl
  7. extractionextracted
  8. dry with materialThe combined organic extracts were dried (MgSO4)
  9. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-5535a7177e464896b4518d7df2a759c0
Source dataset
uspto-grants-2014_11
Patent number
US08883819B2

Reaction notes

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