反应详情

A solution of methyl 3-bromo-2-methoxy-6-methylbenzoate (Intermediate 91, 20 g) in 1,2-dichloroethane (400 ml) was stirred and illuminated with a 500 W tungsten filament lamp and treated with a catalytic amount of AIBN. Solid 1,3-dibromo-5,5-dimethylhydantoin (20 g) was gradually added over 3 hours until NMR analysis indicated complete conversion to the desired benzyl bromide. After cooling, the mixture was evaporated to dryness and the residue was triturated with cyclohexane and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of DCM and cyclohexane with a gradient of 1-25% to give methyl 3-bromo-6-bromomethyl-2-methoxybenzoate (16.3 g) as an orange solid.

1. temperatureAfter cooling
2. customthe mixture was evaporated to dryness
3. customthe residue was triturated with cyclohexane
4. filtrationfiltered
5. customThe filtrate was evaporated to dryness
6. customthe residue was purified by chromatography on silica
7. washeluting with a mixture of DCM and cyclohexane with a gradient of 1-25%