Lithium Hydroxide → 1-(tert-Butyl)-5-chloro-1H-pyrazole-4-carboxylic acid

HRID 12828Notes

Reaction equation

HRID 12828 reaction equation
C([O:3][C:4]([C:6]1[CH:7]=[N:8][N:9]([C:12]([CH3:15])([CH3:14])[CH3:13])[C:10]=1[Cl:11])=[O:5])C.[Li+].[OH-]>CO.O>[C:12]([N:9]1[C:10]([Cl:11])=[C:6]([C:4]([OH:5])=[O:3])[CH:7]=[N:8]1)([CH3:15])([CH3:13])[CH3:14]

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 13809947ethyl 1-tert-butyl-5-chloro-1H-pyrazole-4-carboxylate

Product 1

HCID 534235531-(tert-Butyl)-5-chloro-1H-pyrazole-4-carboxylic acidYield 91%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

To a solution of 1-tert-butyl-5-chloro-1H-pyrazole-4-carboxylic acid ethyl ester (5 g, 21.7 mmol) in methanol (50 mL) and water (50 mL) was added LiOH (0.63 g, 26.3 mmol). The reaction mixture was stirred at reflux overnight and then concentrated under reduced pressure to remove the methanol. The residue was diluted with water, acidified to pH 2 with concentrated HCl (4 mL), and extracted with ethyl acetate. The organic extracts were evaporated in vacuo to give 1-tert-butyl-5-chloro-1H-pyrazole-4-carboxylic acid (4 g, 91%) which was used without further purification.

Workup

  1. temperatureat reflux overnight
  2. concentrationconcentrated under reduced pressure
  3. customto remove the methanol
  4. additionThe residue was diluted with water
  5. extractionextracted with ethyl acetate
  6. customThe organic extracts were evaporated in vacuo

Sources & evidence

ORD record
ord-ad561129ebf0485f9785850739c0b24a
Source dataset
uspto-grants-2010_06
Patent number
US07728029B2

Reaction notes

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