3-甲基吲哚的合成

Synthesis of 3-methylindole

设计了一条新的合成3-甲基吲哚的工艺路线。以邻乙基苯胺为原料,经与甲酸加热回流缩合反应形成N-甲酰基邻乙基苯胺,再与氢氧化钾反应形成N-甲酰基邻乙苯胺的钾盐,最后升温环合,水解形成3-甲基吲哚。采用正交设计试验的方法对反应条件进行了优化,优化后反应条件为:氢氧化钾与N-甲酰基邻乙基苯胺物质的量比为1.56∶1,溶剂为甲苯,搅拌速率为120 r/min,最终环合反应温度为320℃。在该优化的合成条件下进行的稳定性试验结果较为稳定,3-甲基吲哚平均收率达到了60.62%,产品纯度均大于99%,表明该工艺路线具有较强的可行性。

A new process route for the synthesis of 3-methylindole has been designed.Using o-ethylaniline as the raw material,N-formylo-ethylaniline is formed by heating and reflux condensation reaction with formic acid.Then,it reacts with potassium hydroxide to form a potassium salt of N-formyl-o-ethylaniline.Finally,it is heated and cyclized,hydrolyze to form 3-methylindole.The reaction conditions are optimized using orthogonal design experiments.The optimized reaction conditions are as follows:the molar ratio of potassium hydroxide to N-formyl-o-ethylaniline is 1.56∶1,the solvent is toluene,the stirring rate is 120 r/min,and the final cyclization reaction temperature is 320℃.The stability test results under the optimized synthesis conditions are relatively stable,with an average yield of 3-methylindole reaching 60.62%and product purity exceeding 99%,indicating that the process route has strong feasibility.