Chloroacetaldehyde → Methyl imidazo(1,2-a)pyridine-7-carboxylate

HRID 408569Notes

Reaction equation

HRID 408569 reaction equation
[CH3:1][O:2][C:3](=[O:11])[C:4]1[CH:9]=[CH:8][N:7]=[C:6]([NH2:10])[CH:5]=1.Cl[CH2:13][CH:14]=O.C([O-])(O)=O.[Na+]>C(O)C>[CH3:1][O:2][C:3]([C:4]1[CH:9]=[CH:8][N:7]2[CH:13]=[CH:14][N:10]=[C:6]2[CH:5]=1)=[O:11]

Participants

5

Reactant 3

HCID 33ChloroacetaldehydeHCID 236984Methyl 2-aminopyridine-4-carboxylateHCID 516892Sodium Bicarbonate

Product 1

HCID 15096964Methyl imidazo(1,2-a)pyridine-7-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a solution of 2-amino-isonicotinic acid methyl ester (1 eq.) and chloroacetaldehyde (45% w/w in water) (4.5 eq.) in ethanol was added NaHCO3 (1.7 eq.). The reaction mixture was refluxed for 15 h and the solvents removed under reduced pressure. The residue was partitioned between water and EtOAc, the organic layer was washed with a saturated aqueous solution of Na2CO3 and brine, dried over MgSO4, filtered and concentrated under reduced pressure. The crude was purified by chromatography on silica gel (elution with DCM/MeOH: 100/0 to 98/2) to afford imidazo[1,2-a]pyridine-7-carboxylic acid methyl ester.

Workup

  1. temperatureThe reaction mixture was refluxed for 15 h
  2. customthe solvents removed under reduced pressure
  3. customThe residue was partitioned between water and EtOAc
  4. washthe organic layer was washed with a saturated aqueous solution of Na2CO3 and brine
  5. dry with materialdried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customThe crude was purified by chromatography on silica gel (elution with DCM/MeOH: 100/0 to 98/2)

Sources & evidence

ORD record
ord-77e53244b5014dc7b92b1caeab6c24a6
Source dataset
uspto-grants-2014_06
Patent number
US08759334B2

Reaction notes

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