The Copper Catalyzed Oxidative Dehydrogenation Of Nitrogen Hydrogen Bond Coupling Construction Of Nitrogen Nitrogen Bond Synthesis Of Indazole Skeleton

Coupling reaction is one of the main methods of chemical bond formation in organic synthesis, which has been paid more attention by chemists. That through the transition metal catalytic dehydrogenation coupling to form carbon-carbon and carbon-heteroatom is very common, but the literature on the formation of nitrogen-nitrogen bond is rarely reported. As is known to all, compounds containing nitrogen-nitrogen bond is very important in organic compounds, which is widely used in the fields of medicine, pesticide, biology, environment and so on. So to explore a coupling reaction that is fast, effective and environment-friendly method for the formation of nitrogen-nitrogen bond, has important scientific significance and practical value. This article is on the base of copper catalyzed synthesis a series of reaction in our group, then we find a new method that use different subsituent2-amino benzamide as raw materials to synthesize indazolone by dehydrogenation coupling. This synthetic method is simple, short reaction time and material is easy to get, which greatly increased its practical significanse and value. In the middle of the whole reaction process, just a molecule of hydrogen is away, that is accordance with the guiding ideology of atom economy, the sustainable development and green chemistry.This paper mainly does the following several parts of the research:First of all, using the N-Phenyl-2-phenylamino-benzamide as raw material, we explore how the synthesis of 1,2-Diphenyl-1,2-dihydro-indazol-3-one. After a series of optimization of conditions(catalysts, ligands, solvents, temperature, etc.), we choosed the optimum reaction conditions: CuBr(20 mol%) was used as catalyst,DMSO(1 mL) as the solvent, in the air environment, 120 oC under the conditions of condensation reflux stirring for 4 hours. We obtained the target product1,2-Diphenyl-1,2-dihydro-indazol-3-one, and the yield was 94%.Then, in the optimization of the conditions, a series of reaction substrates were explored. The applicability of the reaction substrate and the compatibility of the groups were investigated under the optimum experimental conditions by using the2-amino-benzamide with different substituted groups as the raw materials. Through the results of the experiments, we understand the method for synthesis of multi substituted indazole-3-ketone that is simpler, functional group compatibility good, andthe range of substrates is also good,Finally, in order to further explore, we have made a series of research on the reaction mechanism. We also do the structural characterization of indazoles products,such as infrared, 1HNMR, 13 CNMR, melting point, high resolution mass spectrometry and X-ray diffraction structure data.In a word, this paper through the copper catalyzed dehydrogenation of N-H bond pair united into indazolone, has certain significance as a complement to indazole ketone and its derivative synthesis method.