反应详情

3,4-Dimethoxybenzaldehyde (398.8 g) is dissolved in acetic acid (1.8 liter), and thereto is added dropwise bromine (136 ml) at room temperature over a period of four hours. The mixture is stirred overnight, and thereto is added dropwise slowly again bromine (60 ml), and the mixture is stirred overnight. The reaction solution is added to water (7 liters), and the precipitated crystals are collected by filtration, washed with water, and dissolved in chloroform (2 liters). The chloroform solution is washed, dried, concentrated, and the residue is crystallized from diisopropyl ether to give 6-bromo-3,4-dimethoxybenzaldehyde (470 g) as a colorless crystal.

1. stirringthe mixture is stirred overnight
2. filtrationthe precipitated crystals are collected by filtration
3. washwashed with water
4. dissolutiondissolved in chloroform (2 liters)
5. washThe chloroform solution is washed
6. customdried
7. concentrationconcentrated
8. customthe residue is crystallized from diisopropyl ether