【作者】 杜云飞；

【导师】 赵康；

【作者基本信息】 天津大学 ， 应用化学， 2007， 博士

【摘要】 随着人们对已知吲哚环化合物用途认识的深入和大量新型吲哚环化合物的发现,需要不断开发吲哚类衍生物的合成新方法。本文即针对N-取代吲哚衍生物的合成方法进行研究,主要包含以下几方面:1.为了将苯环侧链上的氮原子在最后一步与芳环碳原子直接键连(C-H官能团化)形成C-N键来构建吲哚环,设计了新型氮正离子中间体并合成了其前体化合物:主要研究了α-芳基-β-酮腈和α-芳基-β-羰基羧酸酯分别与烷基胺、芳胺和烷氧基胺的缩合反应,并对其产物的结构和构型进行了判断。2.在高价碘有机氧化剂—二(三氟乙酰氧)碘苯(PIFA)作用下,2-芳基-3-取代胺基(芳胺或烷基胺)-烯腈类化合物能够在短时间(5 min)内发生分子内环合反应生成N-取代-吲哚-3-腈类衍生物。此外,底物中苄位的氰基还可以替换为酯基,从而使该方法还可以用来合成N-取代(芳基或烷基)-吲哚-3-羧酸酯类衍生物。反应时间和反应收率不明显受苯环取代基团电子效应及空间位阻的影响。反应条件温和,后处理简单。氮正离子历程不能合理解释一些实验结果,故又提出了新的可能反应机理,包括一个氮自由基机理。3.在单电子氧化剂三氯化铁作用下,PIFA作用下不能有效环合的3-烷氧亚胺基-2-芳基-烷腈类化合物能够顺利发生分子内环合反应生成N-烷氧基-吲哚-3-腈类衍生物。反应条件温和,后处理简单。对比实验表明底物中苄位腈基为该反应的必需基团,相同条件下,2-芳基-3-取代胺基-烯腈类化合不能发生分子内环合生成N-取代吲哚化合物。对反应的可能机理进行了研究。4.实验过程中发现3-烷氧亚胺基-2-芳基-烷基腈类化合物在二氧化锰作用下发生苄位碳碳键相连的分子间偶联反应,高产率生成二聚体。当苯环的邻位或对位有甲氧基的时候,该二聚体在三氯化铁作用下发生苄位相连的C-C键(即偶联的碳碳键)断裂,经分子内环合反应生成N-甲氧基-吲哚-3-腈类衍生物,提出了一个可能的反应机理。三氯化铁作用下的类似碳碳键断裂反应未见相关文献报道。更多还原

【Abstract】 With the increased understanding of the existed indole derivatives′application and the continuous discovery of new indole compounds in natural products, there is a demand to develop novel methods for the construction of indole compounds. This paper launches an investigation on the synthetic methodology of N-substituted indole derivatives and covers the following aspects:1. In order to construct the indole compounds by joining the N-moiety on the side chain to the benzene ring, which enables the formation of C-N bond via direct C-H functionalization, several new-type nitrenium ion intermediates were designed and synthesized: the condensation reaction betweenα-aryl-β-ketonitriles andα-aryl-β-carbonyl-carboxylates with alkylamines, arylamines, or alkoxyamines respectively were mainly studied. Furthermore, the structure and the configuration of the final products were established.2. Mediated by hypervalent organoiodine reagent, i.e. phenyliodine bis(trifluoroacetate) (PIFA), 2-aryl-3-arylamino-2-alkenenitriles and 2-aryl-3-alkylamino-2-alkenenitriles were found to undergo intramolecular cyclization to afford N-subustituted (arylated or alkylated)-indole-3-carbonitrile derivatives within a short period of time (5 mins). In addition, the benzylic cyano group in such substrates can be replaced by an ester group, which makes the method applicable to the synthesis of N-aryl or N-alkyl-indole-3-carboxylic ester derivatives. The electronic effects of the substituents on the benzene ring and the steric hindrance do not significantly alter the reaction time and yield. The reaction condition is mild and the work up procedure is simple. Owing to the fact that the nitrenium ion mechanism could not explain well some experimental result, several other mechanisms were proposed, including a nitrogen radical pathway.3. 3-Alkoxyimino-2-aryl-alkylnitriles, which could not efficiently cyclize by PIFA, could undergo intramolecular cyclization to furnish N-alkoxyindole- indole-3-carbonitrile derivatives, mediated by single electron oxidant, i.e. ferric chloride. The reaction condition is mild and the work up procedure is simple. The results of comparative experiments indicate that the benzylic cyano group in the sustrate is indispensable. Under the same reaction condition, 2-aryl-3-amino-2-alkenenitriles were unable to cyclize to give N-substituted indole derivatives. 4. In the presence of manganese dioxide, 3-alkoxyimino-2-ary-alkylnitriles can undergo intermolecular coupling to give dimer in high yields by joining the two benzylic carbons. The formed dimers substituted with methoxy group in the para or ortho positions of the benzene ring will lead to the cleavage of the formed carbon-carbon bond and the subsequent intramolecular cyclization in the presence of ferric chloride, which results in the building of N-alkoxyindole skeleton. A possible mechanism was proposed for the process. To our knowledge, the similar FeCl3-mediated carbon-carbon bond cleavage was not reported before.更多还原