Reaktion #10369

Reaktionsgleichung

NaHCO3

ethanol

2,4,5-trifluoro-3-methoxybenzoic acid

oxalyl chloride

→

title compound

Ausbeute 98.8%

2,4,5-Trifluoro-3-methoxybenzoic acid ethyl ester

Ausbeute 98.8%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITat room temperature for 2.5 hours
2. 2
   EinengenThe mixture is concentrated
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 dichloromethane
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 2,4,5-trifluoro-3-methoxybenzoic acid (2.513 g, 12.19 mmol) in dichloromethane (50 mL) at 0° C. is treated with oxalyl chloride (5.4 mL, 61.9 mmol) followed by N,N-dimethylformamide (4 drops). The mixture is stirred at 0° C. for 5 minutes and then at room temperature for 2.5 hours. The mixture is concentrated to near dryness and then co-evaporated from benzene. The resulting acid chloride is diluted with dichloromethane (50 mL), cooled to 0° C., and then anhydrous ethanol (7.30 mL, 124 mmol) is added dropwise. The resulting solution is stirred at room temperature for 4.5 hours, poured into saturated NaHCO3 solution, and extracted with dichloromethane. The combined organic extracts are washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford the title compound as a light yellow liquid (2.82 g). 1H NMR (CDCl3): δ 7.47 (ddd, 1H), 4.39 (q, 2H), 4.05 (s, 3H), 1.40 (t, 3H).

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