Example 1A; 4-Bromo-5-chloro-2-methylaniline; 321.6 g (2.01 mol) of bromine was slowly added dropwise to 6000 ml of glacial acetic acid solution containing 300.0 g (2.12 mol) of 5-chloro-2-methylaniline at 10-15 °C. After the dropwise addition, the reaction mixture was stirred at room temperature overnight. After completion of the reaction, the precipitate was separated by filtration and the filtrate was washed with ethyl acetate. Subsequently, the resulting solid was stirred with ethyl acetate and saturated sodium bicarbonate solution to separate the organic phase and the solvent was thoroughly removed using a rotary evaporator. After two recrystallizations from hexane, 186 g (38% yield) of the target product 4-bromo-5-chloro-2-methylaniline was obtained.The results of the LC-MS (Method 1) analysis were: retention time Rt = 2.26 min, and mass-to-charge ratio m/z = 220 ([M + H]+).
