Study On Multicomponent Reactions In The Synthesis Of Indole-Containing Heterocycles

The indole nucleus is probably the most well-known heterocycle. Compounds carrying the indole moiety exhibit antibacterial and antifungal activities. Multicomponent reactions (MCRs) are of increasing importance in organic and medicinal chemistry. The strategies of MCRs offer significant advantages over conventional linear-type syntheses for their high degree of atom economy, convergence, ease of execution, and broad applications characters, which are particularly useful to generate diverse chemical libraries of'druglike'molecules for biological screening. In this dissertation, much attention has been focused on the MCRs in the synthesis of indole-containing heterocycles. The whole work is mainly composed of following six parts:Part I: A class of indole-containing activated compounds, 3-cyanoacetyl indoles prepared by the Friedel-Crafts acylation reactions, were employed to synthesize a series of 4-aryl-3,5-dicyano-2,6-di(3′-indolyl)pyridine and 4-aryl-3,5-dicyano-1,4-dihydro-2,6-di(3′-indolyl)pyridine derivatives via one-pot MCRs. The compounds were examined by UV-vis and fluorescence emission spectrum for their special structures and potential optical characterers. Moreover, a series of unsymmetric bis(3′-indolyl)pyridine, as well as tri(3′-indolyl)pyridine and multi indolyl-substituted pyridine derivatives were also obtained.Part II: Series of new 3′-indolyl substituted heterocycles, with which 3′-indolyl group binding in position of the nitrogen-containing nucleus were synthesized via three-component reactions of aldehydes, 3-cyanoacetyl indoles with activated amino compounds under both classical oil bath heating and microwave irradiation (MWI) conditions. This protocol has the advantages of high yields of products, broad substrate scope and easy handling.Part III: A simple and clean procedure for three-component synthesis of spirooxindoles catalysted by triethylbenzylammonium chloride (TEBAC) in aqueous medium is described. Particularly valuable features of this method include environmentally benign character, high yields processing and straightforward procedure. Plausible mechanism of the reaction is also presented.Part IV: An efficicent methodology for the synthesis spirooxindoles under MWI in water without catalysts is developed. The current process provides a simple and green method to obtain a variety of novel spirooxindoles, which may have potential biological activities. Part V: A facile microwave-assisted synthesis of new spiro[indoline-pyridine] derivatives by one-pot multicomponent reaction of isatins, activated methylene reagent and enaminones, is described. The products were characterized by spectral data and the structure was confirmed by X-ray crystallographic analysis.