N-(3-bromo-5-fluorophenyl)acetamide (Intermediate 181, 8.7 g, 37.4 mmol) was used as a raw material, which was dissolved in ethanol (30 mL) and then concentrated hydrochloric acid (80 mL) was slowly added. The reaction mixture was heated to 100 °C and kept for 1 h for the reaction. After completion of the reaction, the mixture was cooled to room temperature and neutralized with 5 N sodium hydroxide solution. The crude product was extracted with ethyl acetate (2 x 100 mL) and the combined organic layers were washed with brine and dried over anhydrous magnesium sulfate. After filtration, the solvent was removed by concentration under reduced pressure. Purification by silica gel column chromatography using a gradient elution with 5-10% ethyl acetate in hexane solution gave 5.3 g (75% yield) of the yellow oily target product 3-bromo-5-fluoroaniline (Intermediate 180). Mass spectrum (ES+): m/z 190, 192 ([M+H]+), molecular formula C6H5BrFN. 1H NMR (DMSO-d6) δ: 5.46-6.00 (m, 2H), 6.24-6.37 (m, 1H), 6.44-6.53 (m, 1H), 6.54-6.61 (m, 1H).
