Reaktion #41100

Reaktionsgleichung

1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester

LiOH

→

1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid

Ausbeute 80.3%

Lösungsmittel

CH3OH

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux for 4 h
2. 2
   Einengenthe solution was concentrated under reduced pressure
3. 3
   Sonstigeto remove the methanol
4. 4
   workup.ADDITIONThe residue was diluted with water
5. 5
   ExtraktionThe resulting mixture was then extracted with ethyl acetate three times
6. 6
   EinengenThe combined organic extracts were concentrated in vacuo

Vorschrift

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.

Quelle