反应详情

温度

10 °C

To a stirred solution of 3-fluoro-2-methylaniline (25 g, 200 mmol) in acetic acid (140 mL) at 0-5° C. was added hydrogen bromide (100 mL, 200 mmol) then dimethyl sulfoxide (72 mL) was added slowly dropwise (reaction is exothermic and at temperature higher than 5-15° C. produces dibromoisomer). The mixture was stirred at 5-15° C. for 12 h (mixture became clear solution). The resulting solution was cooled to 0° C. and neutralized with sodium hydroxide then with sodium bicarbonate to pH 7. The mixture was extracted with ethyl acetate. The organic layer was concentrated under reduced pressure. Flash chromatography (0-10% ethyl acetate in hexane) gave the desired product as a white solid (23.3 g, 114 mmol, 57% yield). 1H NMR (400 MHz, CHLOROFORM-d) δ (ppm) 7.11 (t, J=8.20 Hz, 1H), 6.35 (d, J=8.98 Hz, 1H), 3.72 (br. s., 2H), 2.07 (d, J=1.95 Hz, 3H).

1. custom(reaction is exothermic and at temperature higher than 5-15° C. produces dibromoisomer)
2. extractionThe mixture was extracted with ethyl acetate
3. concentrationThe organic layer was concentrated under reduced pressure