反应详情

温度

60 °C

2-Fluoro-4-methoxybenzoic acid (10.0 g) was suspended in acetic acid (80 mL). To the suspension was slowly added dropwise bromine (20.7 g)/acetic acid (20 mL) solution. After completion of the dropwise addition, the mixture was stirred at 25° C. for 3 hr and further at 60° C. for 4 hr, the completion of the reaction was confirmed by HPLC. After cooling to room temperature, to the suspension was added dropwise an aqueous solution of sodium sulfite (9.63 g) and water (100 mL). After completion of the dropwise addition, the mixture was stirred at 25° C. for 2 hr, and then for 2 hr under ice-cooling. The precipitated crystals were collected by filtration, washed four times with water (30 mL), and vacuum dried to give 5-bromo-2-fluoro-4-methoxybenzoic acid as white crystals (14.5 g, 99%).

1. additionAfter completion of the dropwise addition
2. temperatureAfter cooling to room temperature, to the suspension
3. additionAfter completion of the dropwise addition
4. stirringthe mixture was stirred at 25° C. for 2 hr
5. temperaturefor 2 hr under ice-cooling
6. filtrationThe precipitated crystals were collected by filtration
7. washwashed four times with water (30 mL), and vacuum
8. customdried