5,6-二甲氧基吲哚的合成

Synthesis of 5,6-dimethoxyindole

利用商业可购买的3,4-二甲氧基苯甲醛为原料,与叠氮乙酸乙酯缩合得到叠氮基肉桂酸甲酯;再经过分子内环化获得5,6-二甲氧基吲哚甲酸酯,通过水解获得5,6-二甲氧基吲哚-2-甲酸,经过脱羧后合成5,6-二甲氧基吲哚,产品总收率为49%。探讨了浓度,反应温度,反应时间三种参数对该路线中环化反应收率的影响。该合成路线具有原料简单、路线短,可操作性强,合成效率高等优点。所有化合物均采用IR,NMR,MS等多种谱学技术进行了结构表征。

The ethyl cinnamate derivative could be synthesized through condensation of commercially available 3,4-dimethoxybenzaldehyde and ethyl azidoacetate.Intramolecular cyclization of ethyl cinnamate could smoothly afford the methyl 5,6-dimethoxyindole-2-carboxylate.Subsequently,5,6-dimethoxyindole-2-carboxylic acid could be obtained by hydrolysis of methyl 5,6-dimethoxyindole-2-carboxylate in nearly quantitative yield.Finally,decarboxylation of 5,6-dimethoxyindole-2-carboxylic acid could smoothly provide the 5,6-dimethoxyindole in good yield.The optimal reaction condition was established by examining the effect of reaction temperature,solvents,and time.The structures of all compounds were confirmed by IR,NMR and HMMS.