Reacción #10365

Ecuación de reacción

ethanol

NaHCO3

oxalyl chloride

2,3,4,6-Tetrafluorobenzoic acid

→

title compound

Rendimiento 60.1%

2,3,4,6-Tetrafluorobenzoic acid ethyl ester

Rendimiento 60.1%

Disolventes

dichloromethane

benzene

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroto yield an oil that
2. 2
   Temperaturacooled to 0° C. under an inert atmosphere
3. 3
   workup.WAITAfter 5 hours at room temperature
4. 4
   Extracciónextracted with chloroform
5. 5
   LavadoThe organic phase is washed with brine
6. 6
   Secadodried over Na2SO4
7. 7
   Filtraciónfiltered
8. 8
   Concentraciónconcentrated under vacuum

Procedimiento

2,3,4,6-Tetrafluorobenzoic acid (4.8 g, 24.7 mmol) in dichloromethane (80 mL) is cooled to 0° C. under a nitrogen atmosphere and treated with oxalyl chloride (11.2 mL, 128 mmol) followed by anhydrous N,N-dimethylformamide (2 drops). The mixture is warmed to room temperature and stirred for 2 hours. The solution is co-evaporated with benzene to yield an oil that is taken up in dichloromethane (80 mL), cooled to 0° C. under an inert atmosphere, and treated with anhydrous ethanol (15 mL, 258 mmol). After 5 hours at room temperature, the solution is poured into saturated NaHCO3 and extracted with chloroform. The organic phase is washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to provide the title compound (3.3 g). This material is used without further purification. 1H NMR (CDCl3): δ 6.93–6.75 (m, 1H), 4.42 (q, 2H), 1.39 (t, 3H).

Fuente