Lithium Hydroxide → 5-bromo-1-methyl-1H-pyrazole-4-carboxylic acid

HRID 1393041Notes

Reaction equation

HRID 1393041 reaction equation
C([O:3][C:4]([C:6]1[CH:7]=[N:8][N:9]([CH3:12])[C:10]=1[Br:11])=[O:5])C.[Li+].[OH-]>CO.O>[Br:11][C:10]1[N:9]([CH3:12])[N:8]=[CH:7][C:6]=1[C:4]([OH:5])=[O:3]

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 53302113Ethyl 5-Bromo-1-methyl-1H-pyrazole-4-carboxylate

Product 1

HCID 596795725-bromo-1-methyl-1H-pyrazole-4-carboxylic acid

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

To a solution of 5-bromo-1-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (6.9 g, 29.6 mmol) in CH3OH (25 mL) and water (25 mL) was added LiOH (0.78 g, 32.6 mmol). The reaction mixture was stirred at reflux for 4 h, and then the solution was concentrated under reduced pressure to remove the methanol. The residue was diluted with water and the solution was acidified to pH 2 with concentrated HCl (˜3 mL). The resulting mixture was then extracted with ethyl acetate. The combined organic extracts were concentrated in vacuo to give 5-bromo-1-methyl-1H-pyrazole-4-carboxylic acid, which was used without further purification.

Workup

  1. temperatureat reflux for 4 h
  2. concentrationthe solution was concentrated under reduced pressure
  3. customto remove the methanol
  4. additionThe residue was diluted with water
  5. extractionThe resulting mixture was then extracted with ethyl acetate
  6. concentrationThe combined organic extracts were concentrated in vacuo

Sources & evidence

ORD record
ord-4d2bb5b4695d4658939281adcfe64e57
Source dataset
uspto-grants-2008_03
Patent number
US07345058B2

Reaction notes

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