Synthesis of 5-amino-1-bromonaphthalene (B): 5-nitro-1-bromonaphthalene (A) (2.5 g, 10 mmol) was dissolved in a solvent mixture of EtOH/AcOH/dioxane/H2O (2:2:2:1, 30 mL). To this solution was added iron powder (5.6 g, 100 mmol) and 2 drops of 2N HCl. The reaction mixture was stirred at 100 °C for 2 h. The reaction was completed by evaporation and removal of the solvent. After completion of the reaction, the solvent was removed by evaporation and the residue was dissolved in 100 mL of dichloromethane (DCM), washed with 5% NaHCO3 solution (3 x 30 mL) and dried over anhydrous Na2SO4. After evaporation of the solvent, the crude product was purified by silica gel column chromatography using DCM/hexane (1:1) as eluent to afford compound B as a white powder (3.0 g, 97% yield). Melting point 65-66 °C. 1H NMR (400 MHz, CDCl3) δ 7.79 (d, J = 8.8 Hz, 1H), 7.76 (d, J = 8.0 Hz, 1H), 7.71 (d, J = 8.4 Hz, 1H), 7.39 (t, J = 7.6 Hz, 1H), 7.28 (t, J = 7.2 Hz, 1H), 6.83 (d J = 7.2 Hz, 1H), 4.18 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 142.5, 133.0, 130.4, 128.0, 125.1, 125.0, 123.9, 121.0, 118.4, 110.9; ESI-MS (m/z) calculated values C10H9BrN [M+ H]+ 222.0, measured value 222.1.Elemental analysis calculated values (C10H8BrN): C, 54.08; H, 3.63; N, 6.31.Measured values: C, 53.81; H, 3.46; N, 6.11.
