Study On The Green Method Of Copper-Catalyzed Synthesis Of 1,2,4-Triazoles And ILs-catalyzed Knoevenagel Condensation Reaction

Green chemistry has been always one of the most important direction of chemical research.Research on green chemistry is around the greening of raw materials, solvents, catalysts, products, and the synthesis methods. Moreover, the formation of C-C and C-N bond has been an active field in organic synthesis. In this dissertation, we investigated the green synthetic method of 1,2,4-triazoles from simple and readily available nitriles under copper-catalyzed condition, and ILs-catalyzed Knoevenagel condensation in the water. Some results were obtained as follows:A green and highly efficient copper-catalyzed method has been developed for one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials,inexpensive Cu(OAc)2 as the catalyst, and the corresponding 1,2,4-triazole derivatives were obtained in moderate to good yields. The reactions underwent sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile and intramolecular dehydration cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives.Knoevenagel condensation has been playing an important role in the formation of C=C bond. The eco-friendly Ionic liquids(ILs) have been used as green solvents and catalysts usually. In this dissertation, A simple, green and highly efficient Knoevenagel condensation has been developed,catalyzed by eco-friendly basic ionic liquids based on N-methyl morpholine(Nmm) in the water. This class of catalysts are compatible with various carbonyl compounds includingaromatic/aliphatic/heterocyclic/?,?-unsaturated aldehydes and aliphatic ketones, meanwhile they are also tolerant of various activated methylene compounds such as malononitrile/ cyano acid ester/acetylacetone/benzothiazole-2-acetonitrile/1H-benzimidazol-2-acetonitrile/thiazolidine-2,4-dione/barbit uric acid. Most of products can be quantitatively synthesized by this protocol under mild condition in the water. At the same time, the majority of target compounds just need to be washed twice with water after solidifying from the reaction system in a few minutes, and did not need to be further purified. The catalysts can be recycled seven times without activity loss. The method will have great application prospect in the mass production.