General procedure for the synthesis of 4-bromo-5-fluoro-2-methylaniline from 5-fluoro-2-methylaniline: In a dry reaction flask, N-bromosuccinimide (NBS, 14.22 g, 80 mmol), 5-fluoro-2-methylaniline (10 g, 80 mmol), and N,N-dimethylformamide (DMF, 200 mL) were added in sequence. The reaction mixture was stirred at 25°C for 12 hours. Upon completion of the reaction, the mixture was slowly poured into ice water and a solid was precipitated. The solid was collected by filtration and washed with cold water to afford 4-bromo-5-fluoro-2-methylaniline (13 g, 71% yield) as a yellow solid. Product mass spectral data: LC-MS m/z 204 ([M + H]+), retention time 1.68 min.
