Reaktion #8209

Reaktionsgleichung

NaH

2-(Trimethylsilylethynyl)-4,6-difluoro-N-carbethoxyaniline

ethyl acetate hexane

→

sodium ethoxide

5,7-difluoro-indole

Ausbeute 78.4%

Lösungsmittel

ethanol

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigereaction
2. 2
   Sonstigeis consumed
3. 3
   TemperaturThe mixture is heated
4. 4
   Temperaturto reflux
5. 5
   Sonstigeis consumed (approx. 1 hour)
6. 6
   SonstigeReaction
7. 7
   Einengenconcentrated
8. 8
   workup.ADDITIONdiethylether is added
9. 9
   Waschenwashed with H2O, brine
10. 10
    Trocknendried (Na2SO4)
11. 11
    Filtrationfiltered
12. 12
    Einengenconcentrated
13. 13
    Sonstigeis purified by flash chromatography (SiO2, ethyl acetate/hexane gradient)

Vorschrift

Fresh sodium ethoxide is prepared by carefully adding NaH (16 g of 60% oil dispersion, 400 mmol) to 550 mL of ethanol under N2. 2-(Trimethylsilylethynyl)-4,6-difluoro-N-carbethoxyaniline (28 g, 100 mmol) in 150 mL of ethanol is added and reaction is stirred at room temperature approximately 45 minutes, while monitoring by TLC (20% ethyl acetate/hexane, UV) until all the starting material is consumed. The mixture is heated to reflux and monitored by TLC until the intermediate material is consumed (approx. 1 hour). Reaction is cooled to room temperature, concentrated, diethylether is added, washed with H2O, brine, dried (Na2SO4), filtered, concentrated, and is purified by flash chromatography (SiO2, ethyl acetate/hexane gradient) to yield 12 g of 5,7-difluoro-indole (78%).

Quelle