Research On C-H Functionalization Of Imidazopyridine Heterocycles

In recent years,imidazopyridine heterocycles have attracted considerable attention from chemists due to their high biologically activity,and their derivatives are widely used in medicinal chemistry.At present,various approaches for synthesizing imidazopyridine heterocycles have been developed.However,currently in the realm of C-H functionalization of imidazopyridine heterocycles,the use of green and efficient synthetic methods are extremely rare,the research methods for C-H functionalization of imidazopyridine heterocycles that have been developed all require the addition of chemical amounts of oxidants,catalysts,additives,and harsh reaction conditions.In this paper,a series of thiocyano or selenocyano substituted imidazopyridines compounds was obtained by catalyst and additive-free regioselective oxidative C-H thio/selenocyanation of arenes and heteroarenes with elemental sulfur/selenium and TMSCN,and virous imide compounds were successfully synthesized by the ring-opening reactions of imidazopyridine heterocycles under photochemical conditions.The main contents of the study are as follows:1.Catalyst and additive-free regioselective oxidative C-H thio/selenocyanation of arenes and heteroarenes with elemental sulfur/selenium and TMSCNOur group has developed a novel strategy for the synthesis of sulfur/selenocyano substituted imidazole heterocyclic compounds.This protocol provides a green method for thio/selenocyanation of arenes and heteroarenes without need of any catalysts,oxidants and additives.It is a distinctive approach for the synthesis of sulfur/selenocyano compounds because this method has the advantages of regioselectivity,simple operation,high efficiency,and broad substrate scope.Notably,the yield of the reaction was high to 93%when elemental sulfur/selenium and TMS-CN were employed as SCN/SeCN sources and dimethyl sulfoxide(DMSO)was used as the solvent as well as the mild oxidant in one-pot.In addition,the strategy conforms to the development of green chemistry and provides a reference for C-H functionalization of imidazopyridine heterocycles.Moreover,it is also beneficial for screening new drugs and enriching imidazopyridine molecular libraries.2.Exploring the ring-opening reactions of imidazo[1,5-a]quinolines for the synthesis of imides under photochemical conditionsIn recent years,photocatalysis is considered to be one of the most powerful strategies in the field of organic synthesis mainly due to their characteristics such as green,environmentally friendly and high efficiency.This paper provides a practical method for the synthesis of imide compounds with commercially available photocatalyst under air and room temperature conditions.It is of great significance for screening of imide-based drugs because it has the advantages of easy operation,5 W LED lamp as light source,transition metal free,and broad substrate scope.Figure[42]table[9]reference[71]...