[Synthesis]
Step 1. 5-Nitrobenzofuran (Compound 104, 1.89 g, 11.63 mmol), iron powder (6.5 g, 116 mmol), 36.5% hydrochloric acid (1 mL), ethanol (30 mL), and water (6 mL) were mixed, stirred, and heated to 100 °C, and the reaction was maintained for 3 hours. After completion of the reaction, the precipitate was filtered and washed with ethanol. The filtrates were combined and the solvent was removed by evaporation to give a residue. The residue was dissolved in dichloromethane (50 mL) and the organic layer was washed sequentially with aqueous sodium bicarbonate (20 mL x 2) and brine (20 mL x 1), dried over magnesium sulfate, filtered and the solvent was evaporated to afford 1-benzofuran-5-amine (Compound 105) as a brown solid (0.8 g, 51% yield).LC-MS: 134 [M + 1]+; 1H NMR ( DMSO-d6): δ 4.8 (s, 2H), 6.57 (m, 1H), 6.67 (m, 1H), 6.69 (m, 1H), 7.21 (d, J = 9.3 Hz, 1H), 7.74 (d, J = 2.4 Hz, 1H). |