反应详情

温度

0 °C

5-(Trifluoromethoxy)isatin (15.0 g, 65 mmol) and potassium hydroxide pellets (4 g) were mixed in water (35 mL) and cooled to 0° C. With vigorous stirring, a solution of 30% aqueous hydrogen peroxide (11.7 g), potassium hydroxide pellets (5.8 g), and water (80 mL) was added drop-wise keeping the temperature below 10° C. After stirring 1 hour at 0° C., glacial acetic acid (22 mL) was added drop-wise, causing foaming and formation of a precipitate. The contents were stirred overnight and filtered to afford the 2-amino-5-trifluoromethoxybenzoic acid as an amber solid (12.5 g, 87%). A small amount was recrystallized from ethyl acetate-hexanes to afford amber needles for an analytical sample and the remaining compound was used without further purification: mp 142.5-144.2° C. 1H NMR (CDCl3, 300 MHz) 7.98 (s, 1H), 7.18 (d, 1H, J=8.0 Hz) 6.62 (d, 1H, J=8.0 Hz), 6.40 (brs, 2H). Anal. Calc'd for CBH6NO3F3: C, 43.45; H, 2.73; N, 6.33. Found: C, 43.40; H, 2.65; N, 6.35.

1. customthe temperature below 10° C
2. stirringThe contents were stirred overnight
3. filtrationfiltered