General procedure for the synthesis of 3-bromo-5-nitroaniline from 3,5-dinitrobromobenzene: To a solution of 1-bromo-3,5-dinitrobenzene (3.0 g, 12 mmol, 1 eq.) in ethanol (15 mL) was added an aqueous 20% (NH4)2S solution (9.0 mL, 26 mmol, 2.2 eq.) at room temperature. The reaction mixture was heated to reflux for 2 hours. After the reaction was completed, it was cooled to room temperature and diluted with ethyl acetate and water. The organic layer was separated, washed with saturated saline and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using ethyl acetate/hexane (1:4) as eluent to give 2.2 g of 3-bromo-5-nitroaniline (84% yield) as an orange solid.1H NMR (CDCl3, 300 MHz): δ 7.70 (s, 1H), 7.41 (d, J = 1.8 Hz, 1H), 7.08 (d, J = 1.5 Hz, 1H), 4.07 (d, J = 1.5 Hz, 1H), 4.07 (d, J = 1.5 Hz, 1H). 1H), 4.07 (br.s, 2H); m/z = 217 (M)+.
