Synthesis Of α-Arylamidine Derivatives And 3-Dibromomethyl-imidazo[1,2-α]pyridine Derivatives

As we all know,the heterocycle compounds greatly facilitate our daily life,especially some heterocycle compounds containing nitrogen,oxygen and sulfur are widely used in medicine,biology,materials and other fields.However,with the rapid development of social science and technology,the demand for it is increasing,so it is particularly important to quickly and efficiently construct the keteneimine intermediate of heterocycle compounds.It has outstanding advantage:the keteneimine intermediate has extremely high selectivity,and it also has extremely high reactivity,fast reaction and high yield.Keteneimine plays an important role in the multicomponent reaction to form different heterocycle compounds.In this paper,the copper-catalyzed terminal alkyne and N-sulfonyl azide compounds are first formed into N-sulfonyl ketene imine intermediates,and then complex hybridization and cyclization reactions are carried out to construct heteroatom compounds.In this paper,keteneimine was used as an intermediate to study two different types of reactions.1 The arylene halides,sulfonyl azides,and water were subjected to a novel series reaction by[3+2]cycloaddition and ring opening to form aryl hydrazines under one-pot conditions of terminal alkynes promotion.The reaction was carried out at room temperature for 12h,and 32 substrates were extended under optimal conditions with good yield（68%-92%）,The productes were confirmed by hydrogen spectrum（¹H NMR）,carbon spectrum(¹³C NMR)and mass spectrometry（HRMS）.In addition,the terminal alkyne could be catalyzed in the reaction,and the used of an arylsulfonium halide as a carbon source for the sulfhydryl group and the addition of water had been shown to be critical to the reaction.The experimental protocol has mild reaction conditions and relatively inexpensive raw materials.2 A scheme for the synthesis of 3-dibromomethyl-imidazo[1,2-α]pyridine derivatives mediated by CBr₄ and reacted with N-（2-pyridyl）indole intermediates were investigated.The reaction was sealed at 100°C for 12h under nitrogen protection,extended 29 substrates under optimal conditions and got good yield（46%-78%）,all the products were characterized by ¹H NMR,¹³C NMR and HRMS.The reaction successfully introduced a halogen group,and finally a 3-dibromomethyl-imidazo[1,2-α]pyridine derivatives were successfully constructed.The method is environmentally friendly,the reaction is efficient,the operation is simple,and the product structure is novel.