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

HRID 12822Notes

Reaction equation

HRID 12822 reaction equation
C([O:3][C:4]([C:6]1[CH:7]=[N:8][N:9]([C:15]([CH3:18])([CH3:17])[CH3:16])[C:10]=1[C:11]([F:14])([F:13])[F:12])=[O:5])C.[Li+].[OH-]>CO.O>[C:15]([N:9]1[C:10]([C:11]([F:13])([F:14])[F:12])=[C:6]([C:4]([OH:5])=[O:3])[CH:7]=[N:8]1)([CH3:18])([CH3:16])[CH3:17]

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 2782985Ethyl 1-(tert-butyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

Product 1

HCID 14820391-tert-Butyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acidYield 80.3%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

To a solution of 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (5 g, 21.2 mmol, purchased from Bionet) in CH3OH (45 mL) and water (45 mL) was added LiOH (0.54 g, 22.5 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. The resulting mixture was then extracted with ethyl acetate three times. The combined organic extracts were concentrated in vacuo to give 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid (4.02 g, 80%), 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 three times
  6. concentrationThe combined organic extracts were concentrated in vacuo

Sources & evidence

ORD record
ord-7c97ea2069d945458aadd4baa1d276b4
Source dataset
uspto-grants-2010_06
Patent number
US07728029B2

Reaction notes

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