反应详情

Methyl 4-methylsalicylate (98.1 g, 590 mmoles) was dissolved in carbon tetrachloride (600 mL), and N-bromosuccinimide (105.0 g, 590 mmoles) and benzoyl peroxide (0.7 g, 3 mmoles) were added. The mixture was refluxed under nitrogen. After 2 hours, an additional portion (0.7 g) of N-bromosuccinimide was added. Reflux was continued for 16 hours. The reaction mixture was cooled to room temperature and the solid removed by filtration. The yellow filtrate was evaporated to dryness to afford a thick yellow syrup that solidified on standing. Hexanes (500 mL) was added to the solid, and the mixture was boiled until almost all solids dissolved. The hot hexanes solution was filtered and concentrated until a solid just began to precipitate. The mixture was heated to dissolve the solid, and the solution was allowed to cool slowly to room temperature. Pale yellow crystals formed slowly. The mixture was then chilled in ice for 2 hours to complete crystallization. Finally, the solid was filtered, washed with cold hexanes (100 mL), and dried in vacuo to afford 83.5 g (58% yield) of methyl 4-bromomethylsalicylate (m.p. 73°-75° C., open capillary, uncorrected).

1. temperatureThe mixture was refluxed under nitrogen
2. temperatureReflux
3. waitwas continued for 16 hours
4. customthe solid removed by filtration
5. customThe yellow filtrate was evaporated to dryness
6. customto afford a thick yellow syrup that solidified
7. dissolutiondissolved
8. filtrationThe hot hexanes solution was filtered
9. concentrationconcentrated until a solid
10. customto precipitate
11. temperatureThe mixture was heated
12. dissolutionto dissolve the solid
13. temperatureto cool slowly to room temperature
14. customPale yellow crystals formed slowly
15. temperatureThe mixture was then chilled in ice for 2 hours
16. customcrystallization
17. filtrationFinally, the solid was filtered
18. washwashed with cold hexanes (100 mL)
19. customdried in vacuo