| abstract |
The present invention relates to an improved process for the preparation of trialkoxy-3,4,5 benzaldehyde and more particularly of trimethoxy-3,4,5 benzaldehyde from 5-bromo-4-hydroxy-3-methoxy-benzaldehyde.n n n More precisely, the invention is a process for preparing 4,5-dialkoxy-3-methoxy-benzaldehyde from 5-bromo-4-hydroxy-3-methoxy-benzaldehyde, characterized in that the intermediate compounds are carried out successively and without separation: - hydrolysis of 5-bromo-4-hydroxy-3-methoxy benzaldehyde to 4,5-dihydroxy-3-methoxy benzaldehyde, by an alkali metal hydroxide, in water and in the presence of a copper catalyst: the etherification of 4,5-dihydroxy-3-methoxy-benzaldehyde obtained previously using a lower alkyl halide in an aqueous medium and maintaining the pH at selected values, optionally in the presence of a catalyst.n n n The 3,4,5-trimethoxybenzaldehyde which can be prepared according to this process is used in particular for the preparation of pharmaceutical products. |