Reaktion #41146

Reaktionsgleichung

1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid methyl ester

sodium hydroxide

→

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

Ausbeute 78.0%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   EinengenAt this time, the reaction was concentrated in vacuo
2. 2
   Sonstigeto remove methanol
3. 3
   workup.ADDITIONThe residue was diluted with water (25 mL)
4. 4
   Extraktionwas then extracted with ethyl acetate (1×25 mL)
5. 5
   FiltrationThe resulting precipitate was collected by filtration
6. 6
   Waschenwashed with water and hexanes
7. 7
   Sonstigedried in vacuo

Vorschrift

A solution of 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid methyl ester (2.0 g, 10.19 mmol) in methanol (6.8 mL) cooled to 0° C. was treated dropwise with a 4N aqueous sodium hydroxide solution (5.1 mL, 20.4 mmol). The reaction was allowed to slowly warm to 25° C. The reaction was stirred at 25° C. overnight. At this time, the reaction was concentrated in vacuo to remove methanol. The residue was diluted with water (25 mL) and was then extracted with ethyl acetate (1×25 mL). The aqueous layer was then acidified to pH=1 with a 3N aqueous hydrochloric acid solution. The resulting precipitate was collected by filtration, washed with water and hexanes, and then dried in vacuo to afford 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid (1.43 g, 78%) as a white solid.

Quelle