Reaktion #10364

Reaktionsgleichung

NaHCO3

ethanol

2,3,4,5-tetrafluorobenzoic acid

oxalyl chloride

→

title compound

Ausbeute 100.3%

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

Ausbeute 100.3%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITat room temperature for 1.5 hours
2. 2
   EinengenThe mixture is concentrated to dryness
3. 3
   workup.ADDITIONThe resulting acid chloride is diluted with dichloromethane (50 mL)
4. 4
   Temperaturcooled to 0° C.
5. 5
   workup.STIRRINGThe resulting solution is stirred at room temperature for 4.5 hours
6. 6
   Extraktionextracted with chloroform
7. 7
   WaschenThe combined organic extracts are washed with brine
8. 8
   Trocknendried over Na2SO4
9. 9
   Filtrationfiltered
10. 10
    Einengenconcentrated under vacuum

Vorschrift

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).

Quelle