Study On Synthesis Of Nitrogen-containing Five-membered Heterocyclic Compounds

In recent years, Organic chemists have been working on the synthesis and studying the properties of heterocyclic compounds, especially five nitrogenous heterocyclic compounds, which are one of the core skeletons of many natural products and drug molecules. Meanwhile, five nitrogenous heterocyclic compounds are attracted in pharmaceutical chemistry, materials chemistry, organic synthesis chemistry and natural product chemistry.Although, the synthesis methods of five nitrogen heterocyclic compounds are numerous, the study of these synthesis methods are in the ascendant because of widespread application of these compounds. Therefore, it is important to explore an effective and environmental friendly method to synthesis five nitrogenous heterocyclic compounds.In this paper, we disclosed new method to synthesize polysubstituted oxazole derivatives, imidazole derivatives, triazole derivatives and pyrazole derivatives.1. First we synthesized the derivative of diphenyl ketone ethylene, then diphenyl ketone react with 2,3-butanedione at the existence of ammonium acetate to give 2,3,5-triaryl oxazole and 2-methyl-4,5-diaryl imidazole in one pot. This method has the following advantages compare with the method published in literature:A) the raw material of diphenylethyl diones are cheap and easy to get rather than aldehyde compounds; B) the catalyst is inexpensive and environmental friendly ammonium acetate rather than transition metal; C)the substituted oxazole and imidazole compounds were generated in one pot. All compounds were characterized by IR and NMR and some products have been characterized by X-Ray diffraction method.2. We obtained 4,5-diaryl-1,2,3-triazoles via pre-synthesized acrylonitriles reacted with sodium azide taking copper iodide as the catalyst. All products have been characterized by NMR and IR and part of the products have been characterized by X-Ray diffraction method.3. We first optimized the conditions for the synthesis of toluenesulfonylhydrazide and tosylhydrazones, then tosylhydrazones reacted with acrylonitrile in the present of alkali to obtain 3,4,5-triaryl-1,2-pyrazole. All products have been characterized by NMR and IR and some products have been characterized by X-Ray diffraction method.