Boraei Ahmed T A, El Ashry El Sayed H, Barakat Assem, Ghabbour Hazem A
Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt.
Chemistry Department, Faculty of Science, Alexandria University, P. O. Box 426, Ibrahimia, Alexandria 21321, Egypt.
Molecules. 2016 Mar 10;21(3):333. doi: 10.3390/molecules21030333.
Successful alkylations of the nitrogen of ethyl indol-2-carboxylate were carried out using aq. KOH in acetone. The respective N-alkylated acids could be obtained without separating the N-alkylated esters by increasing the amount of KOH and water. The use of NaOMe in methanol led to transesterification instead of the alkylation, while the use of NaOEt led to low yields of the N-alkylated acids. Hydrazinolysis of the ester gave indol-2-carbohydrazide which then was allowed to react with different aromatic aldehydes and ketones in ethanol catalyzed by acetic acid. Indol-2-thiosemicarbazide was used in a heterocyclization reaction to form thiazoles. The new structures were confirmed using NMR, mass spectrometry and X-ray single crystal analysis.
在丙酮中使用氢氧化钾水溶液成功实现了吲哚 - 2 - 羧酸乙酯氮原子的烷基化反应。通过增加氢氧化钾和水的用量，可以在不分离N - 烷基化酯的情况下得到相应的N - 烷基化酸。在甲醇中使用甲氧基钠会导致酯交换反应而非烷基化反应，而使用乙氧基钠则会导致N - 烷基化酸的产率较低。酯的肼解反应生成吲哚 - 2 - 碳酰肼，然后在乙酸催化下，使其与乙醇中的不同芳香醛和酮反应。吲哚 - 2 - 硫代氨基脲用于杂环化反应以形成噻唑。通过核磁共振、质谱和X射线单晶分析对新结构进行了确认。
