Reaktion #74168

Reaktionsgleichung

4-bromo-5-(2,6-difluoro-3-nitrophenyl)-1H-pyrazole

methyl iodide

→

solid

Ausbeute 57.5%

4-Bromo-3-(2,6-difluoro-3-nitrophenyl)-1-methyl-1H-pyrazole

Ausbeute 57.5%

Lösungsmittel

dichloromethane

sodium hydroxide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   SonstigeThe phases were separated
3. 3
   Waschenthe organic layer was washed with water
4. 4
   Trocknendried over anhydrous sodium sulfate
5. 5
   Einengenconcentrated
6. 6
   SonstigeThe crude residue was purified by flash chromatography (eluant: dichloromethane/petroleum ether 2:1)
7. 7
   workup.ADDITIONThe title compound, mixture of the two regioisomers

Vorschrift

To a mixture of 4-bromo-5-(2,6-difluoro-3-nitrophenyl)-1H-pyrazole (0.88 g, 2.9 mmol) and methyl iodide (2 mL, 32 mmol) in dichloromethane (20 mL), tetrabutylammonium bromide (0.32 g, 1 mmol) in 7 N sodium hydroxide (20 mL) was added and the mixture was rapidly stirred at room temperature for 3 h. The phases were separated and the organic layer was washed with water, dried over anhydrous sodium sulfate and concentrated. The crude residue was purified by flash chromatography (eluant: dichloromethane/petroleum ether 2:1). The title compound, mixture of the two regioisomers, was obtained as a waxy solid (0.53 g, 57%).

Quelle