Study On The Mononitrification Of N-aryl Aromatic Formamide

As an important organic functional group,nitro not only have strong electron-withdrawing effect,which could improve electronic effect of integral molecule,but also nitro could be transferred to all kind s of molecular group.For example,it could be transferred to amino.Furthermore,amino group as a active group,it could react with many chemical reagent.Nitro group is widely exists in pharmaceutical molecules,and is also an important functional group for building other fuctional molecules.For example,nitro aromatic amines are widely applied in chemical medicine,plastic,natural products,dyes,and also as synthetic intermediates in the chemical industry.Therefore,the methodology of nitro introduce d on compounds has attracted wide attention.The traditional nitrification method is achieved by using H₂SO₄/HNO₃ mixed acid system,but this method has harsh reaction conditions,severe corrosion on industrial equipment,poor product selectivity,easy to form isomers or polynitrification products,product separation and purification is difficult.This nitrification method used in this study was under mild conditions,and the reaction process was carried out in solid phase without transition metal catalysis.It has the characteristics of high reaction yield,fast reaction speed,easy purification and economical saving.On the basis of reading and summarizing a large number of literatures,the authors put forword a method of solid phase synthesis of nitroaromatic amines catalyzed by non-transition metal and promoted by high iodide through the exploring and optimizing conditions.In this paper,the nitrification reaction of N-aryl-2-pyridine formamide and its analogues was studied as follows:This thesis first introduced the research background and significance of the subject,elaborated the characteristics of this subject nitrification method,analyzes its advantages,and finally determined the research content of the subject.Its main contents include the following three aspects.Firstly,in this study,N-aryl aromatic were obtained by one-step condensation reaction with cheap and readily available aryl formic acid and aryl amine as raw materials.Then sodium nitrite?NaNO₂?was used as the nitro source,and N-phenyl-2-pyridine formamide was used as the aryl source for the exploration and screening of the reaction,and the optimal conditions for the nitrification reaction were obtained,that is,the addition of difluoroacet oxyiodobenzene into the reactant for grinding.Under the optimal conditions,the adaptability of different substrates was investigated.Compared with the reported nitrification method,this method is characterized by mild reaction conditions,environmental friendliness,high selectivity of location,cheap and easy to get raw materials,and simple operation.It provides an efficient and economical method for the synthesis of nitroaromatic amines.Secondly,the free radical signal was detected by adding free radical catcher and electron magnetic spin resonance?EPR?to the reaction system.Thirdly,all target products of this study were determined by ¹H NMR,¹³C NMR,³¹P NMR,¹⁹F NMR,HRMS and ESI.Especially,the spatial configuration of 2n product was verified by X-ray single crystal diffraction.The results indicate the structure of the nitration products is right.