Water → 7-Bromoimidazo[1,2-a]pyridine-3-carboxylic acid

HRID 79241Notes

Reaction equation

HRID 79241 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][N:5]2[C:8]([C:11]([O:13]CC)=[O:12])=[CH:9][N:10]=[C:4]2[CH:3]=1.O.[OH-].[Li+].O1CCCC1.C(O)C.O.O>ClCCl>[Br:1][C:2]1[CH:7]=[CH:6][N:5]2[C:8]([C:11]([OH:13])=[O:12])=[CH:9][N:10]=[C:4]2[CH:3]=1

Participants

6

Reactant 4

HCID 962WaterHCID 168937Lithium hydroxide, monohydrateHCID 18504229Ethanol tetrahydrofuran waterHCID 67260906Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

Product 1

HCID 672614887-Bromoimidazo[1,2-a]pyridine-3-carboxylic acidYield 61.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate (15 g, 56 mmol) and lithium hydroxide monohydrate (3 g, 71.4 mmol) were mixed with a 1:2:1 mixture of tetrahydrofuran/ethanol/water (560 mL). The mixture was stirred at ambient temperature for 16 hours. The solvent was removed under vacuum to give a yellow gum. Water (300 mL) and dichloromethane were added and the phases were separated. The aqueous phase was cooled in an ice-water bath before adjusting the pH to 3 using 2N sulfuric acid. The product precipitated, was collected by filtration and was washed with a small amount of water (50 mL) then dried under vacuum to give 7-bromoimidazo[1,2-a]pyridine-3-carboxylic acid (8.3 g) as an off-white solid.

Workup

  1. customThe solvent was removed under vacuum
  2. customto give a yellow gum
  3. customthe phases were separated
  4. temperatureThe aqueous phase was cooled in an ice-water bath
  5. customThe product precipitated
  6. filtrationwas collected by filtration
  7. washwas washed with a small amount of water (50 mL)
  8. customthen dried under vacuum

Sources & evidence

ORD record
ord-bfe44e22be44433eb52275e8825d5d1a
Source dataset
uspto-grants-2014_09
Patent number
US08841455B2

Reaction notes

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