The general procedure for the synthesis of 1-bromo-4-chloro-2-iodobenzene from 2-bromo-5-chloroaniline was as follows: 2-bromo-5-chloroaniline (50 g, 242.16 mmol) was dissolved in hydrochloric acid (500 ml) and the mixture was stirred at 0°C. Subsequently, a solution of sodium nitrite (NaNO2, 17.5 g, 253.62 mmol) dissolved in water (50 ml) was added dropwise to the reaction mixture over a period of 1 hour, keeping the temperature at -10°C. Next, a solution of potassium iodide (KI, 44.2 g, 266.26 mmol) dissolved in water (50 ml) was added dropwise to the reaction system at 0°C with continuous stirring for 1 hour. After completion of the reaction, the reaction mixture was extracted with ethyl acetate, filtered and the organic phase was dried with magnesium sulfate (MgSO4). The dried organic layer was filtered under reduced pressure and subsequently concentrated by evaporation under reduced pressure. Finally, the concentrate was purified by column chromatography to afford the target compound 1-bromo-4-chloro-2-iodobenzene (62 g, yield: 66%).
