2,3-Diaminopyridine → Ethyl 8-amino-3-methylimidazo[1,2-a]pyridine-2-carboxylate

HRID 1369585Notes

Reaction equation

HRID 1369585 reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][CH:5]=[CH:4][N:3]=1.[CH2:9]([O:11][C:12](=[O:18])[C:13](=O)[CH:14](Br)[CH3:15])[CH3:10].C(=O)([O-])[O-].[Na+].[Na+]>COCCOC>[NH2:8][C:7]1[C:2]2[N:3]([C:14]([CH3:15])=[C:13]([C:12]([O:11][CH2:9][CH3:10])=[O:18])[N:1]=2)[CH:4]=[CH:5][CH:6]=1

Participants

5

Reactant 3

HCID 99562,3-DiaminopyridineHCID 10340Sodium CarbonateHCID 11117285Ethyl 3-bromo-2-oxobutanoate

Product 1

HCID 22672637Ethyl 8-amino-3-methylimidazo[1,2-a]pyridine-2-carboxylateYield 34%

Reagents, catalysts & solvents 1

HCID 80711,2-DimethoxyethaneSolvent

Procedure

A solution of 2,3-diaminopyridine (6.8 g, 62 mmol) and 3-bromo-2-oxo-butyric acid ethyl ester (13 g, 62 mmol) in 1,2-dimethoxyethane (150 ml) was refluxed for 2 h. Sodium carbonate (6.5 g, 62 mmol) was added and the mixture was refluxed for 2 h. The solids were isolated by filtration and washed with dichloromethane:methanol (10:1). The filtrate and washings were combined and the solvents were removed under reduced pressure. The oily residue was washed with petroleum ether and was purified twice by column chromatography on silica gel using 1) dichloromethane:methanol (10:1) 2) ethyl acetate as eluent to give 4.6 g (34%) of the title compound.

Workup

  1. temperaturethe mixture was refluxed for 2 h
  2. customThe solids were isolated by filtration
  3. washwashed with dichloromethane:methanol (10:1)
  4. customthe solvents were removed under reduced pressure
  5. washThe oily residue was washed with petroleum ether
  6. customwas purified twice by column chromatography on silica gel using 1) dichloromethane:methanol (10:1) 2) ethyl acetate as eluent

Sources & evidence

ORD record
ord-ef5b13daf2b640889a2126a99f9bd955
Source dataset
uspto-grants-2003_06
Patent number
US06579884B1

Reaction notes

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