General procedure for the synthesis of 4-bromonaphthalen-2-amine from 1-bromo-3-nitronaphthalene: 4-bromo-2-nitronaphthalene (240 mg, 0.95 mmol) was dissolved in ethanol (3 mL), and stannous(II) chloride dihydrate (2.1 g, 9.5 mmol) was added. The reaction mixture was heated to reflux for 3 hours. After completion of the reaction, the solvent was removed by evaporation and the residue was poured into water and extracted with ethyl acetate. The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to afford the target product 4-bromonaphthalen-2-amine (79% yield, brown solid). The product was characterized by 1H-NMR (400 MHz, CDCl3) with chemical shifts of δ 8.05 (d, J = 8.4 Hz, 1H), 7.56 (d, J = 8.2 Hz, 1H), 7.39 (ddd, J = 8.2, 6.8, 1.2 Hz, 1H), 7.33-7.29 (m, 1H), 7.29 (d, J = 2.2 Hz. 1H), 6.95 (d, J = 2.1 Hz, 1H), 3.83 (bs, 2H).
