Hydrochloric Acid → Imidazo[1,2-a]pyridine-2-carboxylic acid

HRID 872846Notes

Reaction equation

HRID 872846 reaction equation
[N:1]1[C:2]([C:10]([O:12]CC)=[O:11])=[CH:3][N:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=12.[OH-].[Li+].Cl>C1COCC1.O>[N:1]1[C:2]([C:10]([OH:12])=[O:11])=[CH:3][N:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=12

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 3939Lithium HydroxideHCID 818807Ethyl imidazo[1,2-a]pyridine-2-carboxylate

Product 1

HCID 2062168Imidazo[1,2-a]pyridine-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent2×

Procedure

Into a flask containing a mixture of ethyl imidazo[1,2-a]pyridine-2-carboxylate (1 g, 5.26 mmol), THF (5 ml) and water (5 ml), lithium hydroxide (0.378 g, 15.77 mmol) was added and stirred overnight at RT. The pH of the reaction mixture was adjusted to 2 with 2 M HCl and THF was evaporated. The remaining water phase was extracted with ethyl acetate and the combined ethyl acetate phases were dried. The product had precipitated into the water phase. Water was evaporated, and the remaining solid recrystallized from methanol. The product was used as a salt in the next step. 1H-NMR (400 MHz; DMSO-d6): δ 7.23-7.26 (m, 1H), 7.63-7.70 (m, 1H), 7.76 (dd, 1H), 8.72 (s, 1H), 8.73-8.77 (m, 1H).

Workup

  1. additionInto a flask containing
  2. additionwas added
  3. customwas evaporated
  4. extractionThe remaining water phase was extracted with ethyl acetate
  5. dry with materialthe combined ethyl acetate phases were dried
  6. customThe product had precipitated into the water phase
  7. customWater was evaporated
  8. customthe remaining solid recrystallized from methanol

Sources & evidence

ORD record
ord-f064cd527bf84b528e6f3efe4ef403c7
Source dataset
uspto-grants-2015_03
Patent number
US08975254B2

Reaction notes

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