Methanol → Methyl imidazo[1,2-a]pyridine-8-carboxylate

HRID 1423031Notes

Reaction equation

HRID 1423031 reaction equation
[N:1]1[CH:2]=[CH:3][N:4]2[CH:9]=[CH:8][CH:7]=[C:6]([C:10]([OH:12])=[O:11])[C:5]=12.S(Cl)(Cl)=O.[CH3:17]O>>[CH3:17][O:11][C:10]([C:6]1[C:5]2[N:4]([CH:3]=[CH:2][N:1]=2)[CH:9]=[CH:8][CH:7]=1)=[O:12]

Participants

4

Reactant 3

HCID 887MethanolHCID 24386Thionyl ChlorideHCID 11715357Imidazo[1,2-a]pyridine-8-carboxylic acid

Product 1

HCID 15098894Methyl imidazo[1,2-a]pyridine-8-carboxylate

Procedure

To a stirred solution of imidazo[1,2-a]pyridine-8-carboxylic acid (3.8 g, 23 mmol) in methanol (100 mL) is added thionylchloride (8.36 g, 70.3 mmol) and the mixture is warmed at reflux. After 8 hours, the reaction mixture is cooled to room temperature and quenched with saturated aqueous NaHCO3, and extracted with EtOAc (3×250 mL). The combined organic layers are washed with water, brine, dried over Na2SO4 and concentrated. The crude material is purified by silica gel chromatography eluting with 3% MeOH in CH2Cl2 to afford imidazo[1,2-a]pyridine-8-carboxylic acid methyl ester. Mp: 71-73° C.

Workup

  1. temperaturethe mixture is warmed
  2. temperatureat reflux
  3. customquenched with saturated aqueous NaHCO3
  4. extractionextracted with EtOAc (3×250 mL)
  5. washThe combined organic layers are washed with water, brine
  6. dry with materialdried over Na2SO4
  7. concentrationconcentrated
  8. customThe crude material is purified by silica gel chromatography
  9. washeluting with 3% MeOH in CH2Cl2

Sources & evidence

ORD record
ord-85dc751de7d84869972e614a832321dd
Source dataset
uspto-grants-2015_01
Patent number
US08927550B2

Reaction notes

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