Iodine-mediated Oxidative N–N Coupling Of Secondary Amines To Hydrazines

Compounds containing N–N bonds are widely found in nature,and only 200natural products have been found with a vast degree of structural diversity which are commonly found in azos,hydrazines and various heterocyclics.It also plays an important role in the synthesis field and has been used to synthesize various polymers,dendrimers and bioactive molecules.Given the various advantages of such compounds,researchers have developed a number of methods for constructing N–N bonds,however,much less effort has been focused on the oxidative N–N coupling of secondary amines.In the field of organic synthesis and medicinal chemistry,hydrazines are a very important class of intermediates,which have received extensive attention at home and abroad,and have extremely important applications and good development prospects.Therefore,in this topic we focus on the synthesis of hydrazines.An I₂-mediated N–N coupling reaction has been established for oxidative dimerization of N-aryl aminopyridines to a variety of novel hydrazine derivatives under mild conditions.The method uses iodine molecule as a sole oxidant and is environmentally friendly;It does not require use of transition metals and can be conveniently carried out on a gram scale;It has mild reaction condition and simple operation that a pre-stirred mixture of I₂ and KI in DMSO was treated with substrates and K₂CO₃,and then heated to 60°C;It is applicable to diphenylamine and N-alkylaniline substrates.Through the screening of conditions,we have extended a series of considerable yields of hydrazine derivatives under optimal conditions.