氧化吲哚合成方法的改进

Improvement in Synthesis of Oxindole

以邻硝基甲苯为原料,在乙醇钠催化下与草酸二乙酯缩合,经水解、氧化、酸化制得邻硝基苯乙酸,收率62.1%。在FeCl3/活性炭催化下,邻硝基苯乙酸经水合肼还原、环合制得氧化吲哚。考察了还原剂水合肼用量、催化剂FeCl3·6H2O用量及反应时间对氧化吲哚收率的影响。结果表明,在邻硝基苯乙酸用量3.62g、水合肼用量5.0g、FeCl3·6H2O用量0.4g、活性炭用量2.0g、回流温度反应5.0h的最佳操作条件下,氧化吲哚收率达88.1%,两步总收率达54.7%。

o - Nitrophenylactic acid was synthesized by condesation of o - nitrotoluene with diethyl oxalate, hydrolysis, oxidation and acidization with the yield of the product 62.1%. o - Nitmphenylacetic acid was further converted to oxindole by reduction of hydrazine hydrate, cyclization in the presence of FeCl3/activated carbon with the yield 88.1%. The effects reaction conditions including amount of hydrazine hydrate as reducer and FeCl3·6H2O, and reaction time on the yield of oxindole were examined. The result showed that the yield of oxindole was up to 88.1% under the optimum conditions as follows ： the amount of o - nitrophenylacetic acid, hydrazine hydrate, FeCl3· 6H2O, and activated carbon 8.62,5.0,0.4, and 2.0 g, reaction time 5 hours at reflux temperature.