Under strict light protection, 4-tert-butylaniline (10 g, 68 mmol) was dissolved in DMF (150 mL) and cooled to 0 °C. To this solution, N-bromosuccinimide (NBS, 12.1 g, 68 mmol) was slowly added and stirred continuously at 0 °C for 30 min. Subsequently, the ice bath was removed to bring the reaction mixture to room temperature and stirring was continued for 18 hours. Upon completion of the reaction, the mixture was poured into water (300 mL) and extracted with dichloromethane (CH2Cl2). The organic phases were combined, dried with anhydrous magnesium sulfate (MgSO4) and filtered. The filtrate was evaporated under reduced pressure to give a dark brown tarry crude product. Purification by column chromatography (eluent: petroleum ether/ethyl acetate=20:1) afforded the colorless oily target product 2-bromo-4-(tert-butyl)aniline (13.5 g, 87% yield). Thin-layer chromatography (TLC) analysis showed an Rf value of 0.69 (unfolding agent: petroleum ether/ethyl acetate=5:1).1H-NMR (CDCl3, 300 MHz) data were as follows: δ 7.43 (t, J=1.2 Hz, 1H), 7.14 (m, 1H), 6.72 (d, J=8.1 Hz, 1H), 3.96 (br, 2H). 1.30 (s, 9H).
