Reaktion #41142

Reaktionsgleichung

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

lithium hydroxide

→

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

Ausbeute 92.0%

Lösungsmittel

methanol water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was heated
2. 2
   Temperaturto reflux for 2 hr
3. 3
   Einengenconcentrated to approximately half of the original volume
4. 4
   Extraktionextracted with methylene chloride
5. 5
   TrocknenThe extracts were dried over sodium sulfate
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated

Vorschrift

To a stirred mixture of 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (3.000 g; 11.4 mmol) in methanol/water (1:1 ratio, 50 mL) was added lithium hydroxide (0.383 g; 16.0 mmol) at room temperature. The mixture was heated to reflux for 2 hr, then allowed to cool to room temperature and concentrated to approximately half of the original volume. The resulting mixture was acidified with 1N HCl to ˜pH 1 and extracted with methylene chloride. The extracts were dried over sodium sulfate, filtered and concentrated to provide 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid (2.47 g, 92%).

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