Synthesis Of Benzimidazole Derivatives Based On Heteroatom Wittig-equivalent

In recent years,benzimidazoles have attracted a great deal of attention as they are widely used in new drugs including antihypertensives,GABA A receptor agonists,hepatitis C virus(HCV)and NS5 B polymerase inhibitors,Chemistry has a very important meaning.In recent decades,the development of benzimidazole derivatives has made great strides.One of the important improvements is the efficient synthesis of these functional benzimidazole compounds.The reported methods for the synthesis of benzimidazoles include the condensation of aniline and aldehyde under relatively harsh conditions,the direct oxidative coupling between amine and imine,and the transition metal-catalyzed intramolecular cyclization reaction.However,the reported approach consists mainly of harsh and severe conditions or expensive catalysts.Considering the harsh conditions may lead to the decomposition of substrates or products,to explore the synthesis of benzimidazole conditions are more important.The synthesis of benzimidazoles involves the construction of C-N bonds,an important class of transformations in organic synthesis.Schiff bases represent synthetic nitrogen in all C-N bond formation reactions,however,in some cases,the Schiff base reaction activity is not high enough.Our group recently successfully established an effective C-S functionalization strategy and based on these investigations developed a variety of useful Wittig-like processes.For example,the synthesis of 3-substituted arylisothiazoles by the all-atom Wittig equivalent method provides a novel method for isothiazole.Based on this finding,we are interested in investigating the possibility of constructing C-N bonds in order to synthesize substituted benzimidazoles by means of the equivalent aza method.In this respect,the reaction presents very mild conditions compared to the reported method.In this work,we synthesized 1,2-disubstituted benzimidazoles using o-phenylenediamine derivatives in t-butylsulfoxide and NBS under acid conditions,suggesting a new synthetic route to functional benzimidazoles.Because this synthesis method is still in the preliminary research stage,it cannot guarantee its application to industrialized production.The development of new synthesis processes and the synthesis of benzimidazoles from the perspective of atomic economy of green chemistry,and the direct synthesis of benzimidazoles from simple,inexpensive raw materials in one step is a new direction for future research.