b) Synthesis of 7-bromoquinolin-3-amine: 2-(7-bromoquinolin-3-yl)isoindoline-1,3-dione (10 g, 28.3 mmol) was suspended in ethanol (200 mL), hydrazine (1.777 mL, 56.6 mmol) was added, followed by heating and refluxing for 1 hour. After completion of the reaction, the mixture was allowed to cool to room temperature and the precipitate was collected and washed with a small amount of ethanol. The filtrate was concentrated to dryness to give a gray solid. The resulting solid was dissolved in warm ethanol and adsorbed on silica gel. Purification by silica gel column chromatography (eluent: 50-100% ethyl acetate/hexane gradient) afforded the target compound 7-bromoquinolin-3-amine (3.5 g, 56% yield).1H NMR (400 MHz, DMSO-d6) δ ppm: 5.83 (s, 2H), 7.14 (d, J = 2.53 Hz, 1H), 7.49 (dd, J = 8.84, 2.02Hz, 1H), 7.54-7.65 (m, 1H), 7.94 (d, J = 1.77Hz, 1H), 8.46 (d, J = 2.78Hz, 1H).
