Synthesis
（Synthesis of (2-1) 2-bromo-4-iodotoluene (0143): A mixed solution of 3-bromo-4-methylaniline (18.6 g, 0.1 mol) with 6 M hydrochloric acid (80 mL) was cooled to -5 °C and stirred under argon protection. An aqueous solution of sodium nitrite (15 mL, containing 7.35 g of sodium nitrite) was added slowly and dropwise while maintaining the reaction temperature below 0 °C. The reaction temperature was kept below 0 °C and the reaction temperature was kept below 0 °C. After the dropwise addition, the reaction mixture was continued to be stirred at -8 °C for 45 min. Subsequently, potassium iodide (33.2 g, 0.2 mol) was added in batches over a period of 3 hours while ensuring that the reaction temperature did not exceed 0 °C. The reaction mixture was then stirred at -8 °C for 45 min. After the addition was completed, the reaction mixture was allowed to warm up naturally to room temperature. At the end of the reaction, the reaction was quenched by the addition of 10% aqueous sodium bisulfite (50 mL) and then extracted with ether (3 × 50 mL). The organic layers were combined, washed with 10% aqueous sodium bisulfite (50 mL), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate = 20:1) to afford 2-bromo-4-iodotoluene (14.5 g, 49% yield).
References
[1] Patent: JP2018/90561, 2018, A. Location in patent: Paragraph 0087
[2] Photochemical and Photobiological Sciences, 2018, vol. 17, # 3, p. 290 - 301
[3] Patent: US2017/183291, 2017, A1. Location in patent: Paragraph 0142; 0143
[4] Patent: US5206235, 1993, A
