反应详情

N-Bromosuccinimide (44.9 g) was added to a solution of methyl 2,4-dimethylbenzoate (41.36 g) in carbon tetrachloride containing a trace of dibenzoyl peroxide. The mixture was heated under reflux until no orange colour persisted then cooled, filtered and the filtrate evaporated to leave an oil. This was distilled until ~16 g distilate bp 98°-140°/0.8-5 mm (starting material) had been collected. The residue was then heated at atmospheric pressure until no more methyl bromide was evolved, to give a mixture of the title compound and 4-methylphthalide. Addition of hot petrol and filtration from the phthalide gave after evaporation the title compound. τ (CDCl3) 7.48 (3H, s), 6.21 (3H, s), 5.65 (2H, s), 2.6-2.93 (2H, m), 2.18 (1H, d, J=8 Hz).

1. temperatureThe mixture was heated
2. temperatureunder reflux until no orange colour
3. temperaturepersisted then cooled
4. filtrationfiltered
5. customthe filtrate evaporated
6. customto leave an oil
7. distillationThis was distilled until ~16 g distilate bp 98°-140°/0.8-5 mm (starting material)
8. customhad been collected
9. temperatureThe residue was then heated at atmospheric pressure until no more methyl bromide
10. customto give