Reacción #10372

Ecuación de reacción

NaHCO3

ethanol

3-methyl-2,4,5-trifluorobenzoic acid

oxalyl chloride

→

title compound

Rendimiento 77.1%

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

Rendimiento 77.1%

Disolventes

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   Concentraciónconcentrated
2. 2
   Otrodried in vacuo
3. 3
   workup.ADDITIONThe acid chloride is diluted with dichloromethane
4. 4
   Temperaturacooled to 0° C.
5. 5
   workup.STIRRINGThe resulting solution is stirred at room temperature for 20 hours
6. 6
   Extracciónextracted with dichloromethane
7. 7
   LavadoThe organic extracts are washed with brine
8. 8
   Secadodried over Na2SO4
9. 9
   Filtraciónfiltered
10. 10
    Concentraciónconcentrated under vacuum

Procedimiento

A solution of 3-methyl-2,4,5-trifluorobenzoic acid (Shimizu T., Asai T., Kumai S., Jpn. Kokai Tokkyo Koho (1997) Japanese Appl. JP 95-219069, 4.3 g, 22.6 mmol) in dichloromethane (100 mL) at 0° C. is treated with oxalyl chloride (4.2 g, 33 mmol) followed by N,N-dimethylformamide (2 drops). The mixture is stirred at room temperature for 3 hours, concentrated and dried in vacuo. The acid chloride is diluted with dichloromethane, cooled to 0° C., and treated with absolute ethanol (10 mL, 170 mmol). The resulting solution is stirred at room temperature for 20 hours, poured into saturated NaHCO3 solution and extracted with dichloromethane. The organic extracts are washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum to afford the title compound (3.8 g). 1H NMR (200 MHz, CDCl3): δ 7.67–7.26 (m, 1H), 4.44 (q, 2H), 2.27 (dd, 3H), 1.42 (t, 3H).

Fuente