Step B: Synthesis of 2-bromo-3-chloroaniline
To a solution of tert-butyl (2-bromo-3-chlorophenyl)carbamate (0.4 g) in dichloromethane (DCM, 20 mL) was added trifluoroacetic acid (TFA, 10 mL). The reaction mixture was stirred at room temperature for 3 h. The reaction solution was subsequently concentrated by rotary evaporator. Water (10 mL) was added to the concentrated residue and the mixture was extracted with dichloromethane (2 x 20 mL). The organic phase was separated and washed sequentially with saturated aqueous sodium bicarbonate (NaHCO3) and saturated aqueous sodium chloride (NaCl), dried over anhydrous sodium sulfate (Na2SO4), and then the organic phase was concentrated to give the title compound 2-bromo-3-chloroaniline as a solid (0.2 g, 77% yield).
1H NMR (400 MHz, CDCl3) δ 7.03-6.99 (1H, m), 6.85-6.83 (1H, d, J = 8.0 Hz), 6.65-6.63 (1H, d, J = 8.0 Hz), 4.25 (2H, s).
