反应详情

温度

80 °C

The mixture of 3,5-dibromo-3H-isobenzofuran-1-one (B3) (38 g, 130 mmol) in a solution of 10N NaOH (28.6 mL, 286 mmol) and water (240 mL) is heated for 2 h at 80° C. Activated charcoal (2 g) is added and the mixture is refluxed for another 1 hour. Mixture is hot filtered and acidified with 2N methanesulfonic acid (100 mL). The resulting mixture is cooled in an ice-water bath for 1 h. The solid is filtered and washed with water (4×25 mL) and vacuum dried under KOH to yield 4-bromo-2-formyl-benzoic acid (C3) (26.5 g, 89%, mp: 202° C.). Recrystallization: Dissolved 4-bromo-2-formyl-benzoic acid (C3) in hot EtOH (220 mL) and cooled the mixture in an ice-water bath for 4 h. The solid is filtered and rinsed with cold EtOH (3×20 mL). The solid is then vacuum dried over KOH to yield 4-bromo-2-formyl-benzoic acid (16.8 g, 63%, mp: 204-205° C.).

1. temperaturethe mixture is refluxed for another 1 hour
2. filtrationMixture is hot filtered
3. temperatureThe resulting mixture is cooled in an ice-water bath for 1 h
4. filtrationThe solid is filtered
5. washwashed with water (4×25 mL) and vacuum
6. customdried under KOH