反应详情

温度

158 °C

The mixture of 5-bromo-3H-isobenzofuran-1-one (A3) (51.5 g, 242 mmol) in bromobenzene (100 mL) is heated to 158° C. Bromine (18.8 mL, 363 mmol) is added dropwise to the mixture over 2 h. The mixture is stirred for another 30 min. at 158° C. The bromobenzene is removed by distillation under vacuum. The residue is vacuum dried 1 hour at 120° C. to yield a black crystalline residue. Recrystallization: The residue is dissolved in hot isopropyl ether (300 mL). Activated charcoal (1 g) is added, stirred and filtered while hot. The filtrate is cooled in ice-water bath (0° C.) over night. The solid is filtered and is rinsed with cold isopropyl ether (2×10 mL) and vacuum dry over KOH (KOH) to yield 3,5-dibromo-3H-isobenzofuran-1-one (B3) (38 g, 54%, mp: 100° C.).

1. customThe bromobenzene is removed by distillation under vacuum
2. customdried 1 hour at 120° C.
3. customto yield a black crystalline residue
4. customRecrystallization
5. dissolutionThe residue is dissolved in hot isopropyl ether (300 mL)
6. additionActivated charcoal (1 g) is added
7. stirringstirred
8. filtrationfiltered while hot
9. temperatureThe filtrate is cooled in ice-water bath (0° C.) over night
10. filtrationThe solid is filtered
11. washis rinsed with cold isopropyl ether (2×10 mL) and vacuum
12. dry with materialdry over KOH (KOH)