反应详情

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).

1. concentrationconcentrated
2. customdried in vacuo
3. additionThe acid chloride is diluted with dichloromethane
4. temperaturecooled to 0° C.
5. stirringThe resulting solution is stirred at room temperature for 20 hours
6. extractionextracted with dichloromethane
7. washThe organic extracts are washed with brine
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated under vacuum