使用二醋酸碘苯(PIDA)为氧化剂, 在室温无溶剂条件下, 实现了N-烷氧基酰胺类化合物的N—N自偶联反应. 该方法不仅体系简单易操作, 反应效率高, 可以克量级制备产物, 还具有良好的官能团兼容性, 适用于各种不同取代的苯环、芳香杂环及脂肪族酰胺底物, 为不同取代基的N-烷氧基酰胺类化合物的N—N自偶联提供了一种简捷、温和、高效、有潜在应用价值的制备方法. 该条件下已扩展了28种目标化合物, 产率最高达96%.

Organic synthesis usually requires organic solvents to dissolve reactants or catalysts for reaction, but this leads to serious waste of solvents and environmental pollution. The solvent-free organic synthesis reaction method can effectively avoid resource waste and environmental pollution caused by the use of solvents, and without the use of solvents, the concentration of reactants is the highest, it has significant advantages over reactions in solution in terms of reaction speed, reaction operation, yield, etc. Therefore, solvent-free organic synthesis reaction is favored by organic synthesis chemists as a cleaner and more sustainable synthesis reaction method. However, skeleton structures containing N—N bonds are a very important class of structural units, such as azo compounds, hydrazine derivatives, pyrazole, indazole, triazole derivatives, etc. that exist in various natural products, functional drug molecules, and organic materials. Currently, more than 300 drug molecules have been reported to contain N—N bonds. Especially N,N-disubstituted hydrazine has a wide range of physiological and pharmacological activities, such as antihypertensive, anticancer, and antibacterial. Therefore, we reported using iodobenzenediacetic acid (PIDA) as an oxidant, N-alkoxyamide compounds underwent N—N self coupling reaction at room temperature and solvent-free conditions. This method not only has a simple and easy to operate system, high reaction efficiency, and can prepare products at the gram level, but also has good functional group compatibility, suitable for various substituted benzene rings, aromatic heterocycles, and aliphatic amide substrates. This provides a simple, mild, efficient and potentially useful preparation method for N—N self-coupling of N-alkoxyamide compounds with different substituents. Under this condition, 28 coupling products were prepared with a maximum yield of 96%. The typical procedure is as follows: the mixture of N-alkoxyamide (0.2 mmol, 1 equiv.) and oxidant PIDA (0.15 mmol, 0.75 equiv.) is stirred under a magnetic stirrer until the starting material is completely consumed under thin layer chromatography monitoring. After the reaction, the N—N coupling product was purified by silica gel chromatography.