N—N bond, as an important chemical bond, is widely present in various natural products, organic functional materials, and drug molecules, and plays a crucial role. Although there were various synthetic methods for the formation of N—N bonds, the aforementioned reported coupling methods typically rely on expensive oxidants, metal catalysts, noble metal electrodes, expensive light sources, non-environmentally friendly solvents. Therefore, developing efficient, green, and widely applicable N—N bond construction methods has always been one of the research hotspots in the field of organic synthesis. A simple and efficient N—N self coupling reaction synthesis method based on the structural characteristics of diarylamine compounds was developed. This method uses inexpensive and readily available iodobenzene diacetic acid (PIDA) as an environmentally friendly oxidant, and 1,2-dichloroethane (DCE) as a reaction solvent to achieve selective oxidative self coupling between diarylamine molecules under mild conditions at 60 ℃, with a yield of 94%. The reaction system does not require any metal catalysts or additional ligands, making the operation simple and the post-treatment convenient. It effectively avoids the potential residual and toxicity issues associated with traditional metal reagents. Experimental results show that this strategy can efficiently construct a series of hydrazine compounds, including mono- and poly-substituted electron-donating groups, with excellent yields. Moreover, this reaction is particularly suitable for diarylamine substrates with bulky functional groups (such as tert-butyl, poly-substituted aromatic rings, and large fluorescent groups), achieving high yields and effectively solving the problem of difficult synthesis of diarylamines with bulky functional groups. It can still maintain good reactivity and chemical selectivity, demonstrating a wide range of substrate applicability. In summary, this study has established a novel strategy for constructing N—N bonds that is mild in reaction conditions, easy to operate, and economically feasible. This not only provides a greener and more efficient pathway for the synthesis of hydrazine compounds, but also offers new ideas and practical tools for the later modification and structural diversification of functional molecules and drug intermediates.

Key words: iodobenzene diacetic acid, hydrazine compounds, diarylamine, homo-coupling