反応 #10372

反応方程式

NaHCO3

ethanol

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

oxalyl chloride

→

title compound

収率 77.1%

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

収率 77.1%

溶媒

dichloromethane

反応条件

後処理

1. 1
   濃縮concentrated
2. 2
   その他dried in vacuo
3. 3
   workup.ADDITIONThe acid chloride is diluted with dichloromethane
4. 4
   温度cooled to 0° C.
5. 5
   workup.STIRRINGThe resulting solution is stirred at room temperature for 20 hours
6. 6
   抽出extracted with dichloromethane
7. 7
   洗浄The organic extracts are washed with brine
8. 8
   乾燥dried over Na2SO4
9. 9
   ろ過filtered
10. 10
    濃縮concentrated under vacuum

実験手順

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).

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