反应详情

温度

110 °C

Benzotriazol-2-yl-4,6-di-tert-butyl-phenol (48.6 g, 0.15 mol) was placed in a 3-neck 1-L flask equipped with a stir bar, an addition funnel, a reflux condenser, and a flow control adapter. Through a three-way connecting tube the nitrogen flow was diverted to the flask via the condenser and to an oil bubbler. The bubbler was connected to a filtration flask containing aqueous sodium hydroxide. Hydrobromic acid (45% in acetic acid, 300 mL) was added. The system was purged with nitrogen for 15 min. The slurry was heated to 110° C. for 0.5 h and bromine (23.2 mL, 0.45 mol, 3 equivalent) was added dropwise. The addition was completed in 1 h and the mixture was stirred for an additional 1 h. Three more portions of bromine (3×23.2 mL, 3×0.45 mol) were added and stirring continued for one more hour. The flask was cooled to room temperature. Water (200 mL) was added and the mixture was filtered. The solid was collected and dissolved in dichloroethane (0.5 L). The solution was neutralized first with NaOH (aq) and then with NaHCO3 (aq). The organic layer was dried over magnesium sulfate. The drying agent was filtered off. The solvent of the filtrate was removed by rotary evaporation resulting in a viscous oil. Upon addition of acetone (200 mL) yellow crystalline solid was produced. The product was purified by recrystallization from acetone. Purity: 99+%. Yield: 5.1%. Melting point 244-246° C.

1. customequipped with a stir bar, an addition funnel, a reflux condenser, and a flow control adapter
2. customThe bubbler was connected to a filtration flask
3. customThe system was purged with nitrogen for 15 min
4. additionThe addition
5. stirringstirring
6. temperatureThe flask was cooled to room temperature
7. filtrationthe mixture was filtered
8. customThe solid was collected
9. dissolutiondissolved in dichloroethane (0.5 L)
10. dry with materialThe organic layer was dried over magnesium sulfate
11. filtrationThe drying agent was filtered off
12. customThe solvent of the filtrate was removed by rotary evaporation
13. customresulting in a viscous oil
14. customwas produced
15. customThe product was purified by recrystallization from acetone