| Veratraldehyde, 3,4-dimethoxy-benzeneacetaldehyde and its derivatives are important synthetic flavour or medicinal intermediates. In this paper, synthetic route with lower cost and simpler operation was designed to the synthesis of veratraldehyde, 3,4-dimethoxy-benzeneacetaldehyde, two protect products which are 4-(2,2-dimethoxyethyl)-1,2-dimethoxybenzene and 2-(3,4-dimethoxybenzyl)-1,3-dioxolane and two derivatives which are 3,4-dimethoxyphenylacetaldoxime and N-methyl-3,4-dimethoxyphenylamine.The processes are mentioned as follows:1) Veratraldehyde was prepared from pyrocatechol by methylation and vilsmeier reaction. Many factors influence the reaction were studied and the better conditions were got. The yield is above 85%. 1,2-dimethoxybenzen unreacted was recovered with solvent. N-methylformanilide can also be recovered in the form of N-methylphenylamine. The yield has increased 25% and this method has a potential application in production.2) 3,4-Dimethoxy-benzeneacetaldehyde was prepared from veratraldehyde by Darzen's condensation, alkaline hydrolysis and decarboxylation three steps, the raw material used in the literature 2-butyl alcohol, potassium 2-butoxide and 2-butyl chloroacetate are respectively replaced by methanol, sodium methoxide and methyl chloroacetate, and molar ratio of the materials is found. The total yield is 58.3%. So the process can be used in the industry.3) Two protects of 3,4-dimethoxy-benzeneacetaldehyde, 4-(2,2-dimethoxyethyl)-1,2-dimethoxybenzene and 2-(3,4-dimethoxybenzyl)-1,3-dioxolane were prepared by condensation with methanol and ethane-1,2-diol, the yield were 81.0% and 55.9% respectively. 2-(3,4-dimethoxybenzyl)-1,3-dioxolane is new compound.4) Two derivatives, 3,4-dimethoxyphenylacetaldoxime and N-methyl-3,4-dimethoxyphenylamine were synthesized. And the latter was prepared through condensation with monomethylamine, reduction by catalized hydrogenation or sodium borohydride, and then react with hydrochloride three steps.
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