Transition-Metal-Free Synthesis Of Quinoxalines And Isoxazoles Under Basic Conditions

Five or six-membered heterocyclic compounds not only are one of the most common heterocycles, but also are one of the most important heterocycles. They had a wide range of applications in organic synthetic chemistry, organometallic chemistry, materials chemistry, medicinal chemistry, biochemistry and many other areas because of their efficient biological activity and drug activity, and they mainly can be used as pesticides, herbicides, pharmaceuticals, dyes, and so on. In this paper, we made an overview of the different artificial synthesis of quinoxalines and isoxazoles. And then, we summarized our work. This dissertation was composed of the following two parts.1. We introduced the synthesis of quinoxalines. Quinoxalines are one of the most important nitrogen-containing heterocycles since they are useful as biologically active compounds, antibiotics, electroluminescent materials, and dyes. Quinoxalines were attracted the extensive attention because of its unique structure and drug activity. During the last decades, various synthetic strategies were developed for the preparation of substituted quinoxalines. Although they are efficient processes, there are very few general methods that convert commercially available or readily accessible materials in one step into quinoxalines, and they suffer from one or more limitations, for example, the use of expensive reagents, long reaction times, elevated temperature, and poor scope of substrates. Herein, we report a novel approach for the synthesis of quinoxalines in good to excellent yields by the direct oxidative condensation of o-phenylenediamine with arylacetaldehyde. The process involves a one-pot procedure and proceeds smoothly in air without adding any transition-metal catalyst. An inorganic base (K2CO3) is the only reagent required.2. We introduced the synthesis of isoxazoles. Isoxazoles play an important role in the area of five-membered nitrogen-and oxygen-containing heterocyclic compounds as they are prominent structural motif of numerous natural products, we will summarize and review the different artificial synthesis of isoxazoles, and then introduce our work. Transition-metal-free synthesis of isoxazoles from chloro-oximes and alkylβ-diketones under basic conditions. The method is general, convenient, and environmentally benign.