Part B. Synthesis of 6-bromoquinoxalin-2(1H)-one: To a solution of sodium hydroxide (337 mg, 8.4 mmol) in water (2.1 mL) was added the product of Part A (423 mg, 1.4 mmol) and the reaction was stirred for 1 hr at 65°C. The reaction was completed with the addition of sodium borohydride (31.9 mg, 0.84 mmol). Upon completion of the reaction, the solution was cooled to room temperature, diluted with water (4 mL), followed by the addition of sodium borohydride (31.9 mg, 0.84 mmol), and continued to be stirred at room temperature for 1.5 hours. Ice was added to the reaction mixture and 6 μL of hydrochloric acid was added slowly and dropwise until the solution became acidic. The precipitated solid product was collected by filtration, washed with water and dried in a vacuum oven to afford 6-bromoquinoxalin-2(1H)-one (273 mg, 86% yield).
