2-Aminopyridine → Ethyl 2-{imidazo[1,2-a]pyridin-2-yl}acetate

HRID 356276Notes

Reaction equation

HRID 356276 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][N:3]=1.Cl[CH2:9][C:10](=O)[CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13].C(=O)([O-])[O-].[K+].[K+]>C(#N)C>[N:1]1[C:10]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])=[CH:9][N:3]2[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=12

Participants

5

Reactant 3

HCID 104392-AminopyridineHCID 11430Potassium CarbonateHCID 69484Ethyl 4-chloroacetoacetate

Product 1

HCID 10822054Ethyl 2-{imidazo[1,2-a]pyridin-2-yl}acetateYield 8.4%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A solution of 14.6 g of 2-aminopyridine and 25.5 g of ethyl 4-chloroacetoacetate in 200 ml of acetonitrile was heated under reflux for 14.5 hours. At the end of this time, the reaction mixture was freed from the solvent by distillation under reduced pressure. The residue thus obtained was mixed with an aqueous solution of potassium carbonate, after which it was extracted with ethyl acetate. The extract was washed with an aqueous solution of sodium chloride and dried over anhydrous sodium sulfate, after which the solvent was removed by distillation under reduced pressure. The residue was purified by column chromatography through silica gel, using ethyl acetate as the eluent, to give 2.65 g of the title compound having Rf=0.33 (on silica gel thin layer chromatography using ethyl acetate as the developing solvent).

Workup

  1. temperatureunder reflux for 14.5 hours
  2. distillationAt the end of this time, the reaction mixture was freed from the solvent by distillation under reduced pressure
  3. customThe residue thus obtained
  4. extractionafter which it was extracted with ethyl acetate
  5. washThe extract was washed with an aqueous solution of sodium chloride
  6. dry with materialdried over anhydrous sodium sulfate
  7. customafter which the solvent was removed by distillation under reduced pressure
  8. customThe residue was purified by column chromatography through silica gel

Sources & evidence

ORD record
ord-608034d9cb5f444baafef4e88430ceba
Source dataset
uspto-grants-1998_11
Patent number
US05834501

Reaction notes

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