Reaktion #41193

Reaktionsgleichung

1-(2-hydroxy-1,1-dimethyl-ethyl)-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester

LiOH

→

1-(2-hydroxy-1,1-dimethyl-ethyl)-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid

Ausbeute 95.0%

Lösungsmittel

methanol

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux overnight
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-(2-hydroxy-1,1-dimethyl-ethyl)-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (328 mg, 1.17 mmol) in methanol (5 mL) and water (5 mL) was added LiOH (34 mg, 1.4 mmol). The reaction mixture was stirred at reflux overnight, 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-(2-hydroxy-1,1-dimethyl-ethyl)-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid (280 mg, 95%), which was used without further purification.

Quelle