3-Bromo-4-fluorotoluene

542-56-3

583-68-6

452-62-0

Example 4: 84 g of 2-bromo-4-methylaniline and 54.5 g of isobutyl nitrite were slowly added dropwise through two dropping funnels, respectively, to a solution of 160 g of dimethoxyethane containing 37 g of boron trifluoride and 10.3 g of hydrogen fluoride at a temperature of -5°C to 0°C (the dropping process lasted for 1 hour). After the dropwise addition, the reaction mixture was continued to be stirred at 0°C for 15 min, followed by diafiltration. The resulting crystalline diazonium salt was washed with 50 mL of pre-cooled dimethoxyethane and then dried under vacuum at room temperature. A diazonium salt product of 122.5 g was obtained in a yield of 86% of the theoretical value. The decomposition reaction was carried out according to the method of Example 6, resulting in 3-bromo-4-fluorotoluene in 92.4% yield of the theoretical value.