Reacción #10364

Ecuación de reacción

NaHCO3

ethanol

2,3,4,5-tetrafluorobenzoic acid

oxalyl chloride

→

title compound

Rendimiento 100.3%

2,3,4,5-Tetrafluorobenzoic acid ethyl ester

Rendimiento 100.3%

Disolventes

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.WAITat room temperature for 1.5 hours
2. 2
   ConcentraciónThe mixture is concentrated to dryness
3. 3
   workup.ADDITIONThe resulting acid chloride is diluted with dichloromethane (50 mL)
4. 4
   Temperaturacooled to 0° C.
5. 5
   workup.STIRRINGThe resulting solution is stirred at room temperature for 4.5 hours
6. 6
   Extracciónextracted with chloroform
7. 7
   LavadoThe combined organic extracts are washed with brine
8. 8
   Secadodried over Na2SO4
9. 9
   Filtraciónfiltered
10. 10
    Concentraciónconcentrated under vacuum

Procedimiento

A solution of 2,3,4,5-tetrafluorobenzoic acid (4.68 g, 24.1 mmol) in dichloromethane (50 mL) at 0° C. is treated with oxalyl chloride (11.5 mL, 132 mmol) followed by N,N-dimethylformamide (4 drops). The mixture is stirred at 0° C. for 5 minutes and then at room temperature for 1.5 hours. The mixture is concentrated to dryness and subsequently co-evaporated from benzene. The resulting acid chloride is diluted with dichloromethane (50 mL), cooled to 0° C., and anhydrous ethanol (15.0 mL, 256 mmol) is added dropwise. The resulting solution is stirred at room temperature for 4.5 hours, then poured into saturated NaHCO3 and extracted with chloroform. The combined organic extracts are washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford the title compound (5.37 g). 1H NMR (CDCl3): δ 7.67–7.55 (m, 1H), 4.42 (q, 2H), 1.41 (t, 3H).

Fuente