Ethyl chloroformate → Ethyl 2-chloroimidazo[1,2-a]pyridine-3-carboxylate

HRID 82543Notes

Reaction equation

HRID 82543 reaction equation
C([Li])CCC.[Cl:6][C:7]1[N:8]=[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][N:10]2[CH:15]=1.[C:16](Cl)(=[O:20])[O:17][CH2:18][CH3:19]>C1COCC1>[Cl:6][C:7]1[N:8]=[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][N:10]2[C:15]=1[C:16]([O:17][CH2:18][CH3:19])=[O:20]

Participants

5

Reactant 3

HCID 10928Ethyl chloroformateHCID 21139722-Chloroimidazo[1,2-a]pyridineHCID 178418339Butyllithium

Product 1

HCID 21643308Ethyl 2-chloroimidazo[1,2-a]pyridine-3-carboxylateYield 89.7%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

n-Butyllithium (1.6M in hexane, 45.1 mL) was added to a solution of 2-chloroimidazo[1,2-a]pyridine (10 g) in THF (120 mL) at −78° C. After stirring for 30 min, ethyl chlorocarbonate (7.82 g) in THF (10 ml) was added to the mixture at the same temperature and stirred for 1 h and then 10 h at room temperature. The mixture was quenched with water, and extracted with ethyl acetate, and the extract was washed with brine, and dried over magnesium sulfate. The residue was purified by column chromatography (silica gel, eluted with 10%-50% EtOAc in hexane) to give ethyl 2-chloroimidazo[1,2-a]pyridine-3-carboxylate (13.20 g) as an off-white solid.

Workup

  1. stirringstirred for 1 h
  2. custom10 h
  3. customat room temperature
  4. customThe mixture was quenched with water
  5. extractionextracted with ethyl acetate
  6. washthe extract was washed with brine
  7. dry with materialdried over magnesium sulfate
  8. customThe residue was purified by column chromatography (silica gel, eluted with 10%-50% EtOAc in hexane)

Sources & evidence

ORD record
ord-09efbdb4cbb5426cb06c1f8b02650b1a
Source dataset
uspto-grants-2014_09
Patent number
US08846713B2

Reaction notes

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