A New Method For Synthesis Of 3,5-dichloroaniline And Studies On Reactions Of 2-trifluoromethyl-1,3-envnes With Nucleophilic Reagent

3,5-Dichloroaniline is an important intermediates of pharmaceutical,pesticide and dye.This compound is widely used in medicine,dyes,pigments,photochromic materials,synthesis of plant growth promoters.Recently,the intermediates 3,5-dichloroaniline has become a trend in short supply owing to the increasing yield of ring imide kind of agricultural fungicide,Therefore,the research for a simple,economic and industrializated synthetic method for such compound has become a certain practical significance.On the other hand,because the fluoride atoms have a strong draw point and a very small atomic radius,the introduction of fluorine atoms or fluorine-containing groups into the organic compound molecules may result in some changes in the physical and chemical properties of the nonfluorinated products,such as good reactivity and good lipophilic effect and metabolic barrier effect.In particular,many fluorine-containing organic molecules have some physiological activities that are different from their non-fluorine analogs,make it get more and more application in the field of medicine and biology.Therefore,the study for the synthesis of various types of fluorine-containing compounds has a very important significance.Inthe first part of the dissertation,we have developed a simple new synthetic approachto 3,5-dichloroaniline from 1,3,5-trichlorobenzene.It was found that 3,5-dichloroaniline can be obtained in high yield in one step via palladium catalyzed cross-coupling reaction of 1,3,5-trichlorobenzene with an ammonia or ammonium salt through proper choice of base and ligand.In the second part of the dissertation,we have studied the silver-catalysed tandem hydroamination and cyclization of 2-trifluoromethyl-1,3-enynes with primary amines.We have developed a new method for the synthesis of 4-trifluoromethyl-2,4-disubstituted-2,5-dihydropyrrole derivatives via double hydroamination.It has' been found that 4-trifluoromethyl-2,4-disubstituted-2,5-dihydropyrrole derivatives are very useful organic synthetic intermediates for synthesizing proline,pyrrolidone,pyrrole and fluoropyrrole derivatives.In the third part of the dissertation,the selective nucleophilic addition reaction of 2-trifluomethyl-1,3-conjugated enynes with thiophenol was studied.It was found that the addition pattern such as 1,2-addition and 3,4-addition can be controlled by using different reaction solvents,functionalized alkynes and dienes derivatives can be obtained respectively.Tetrasubstituted olefins bearing sulfur and iodine elements which has a potential anti-cancer activity can be synthesized via iodine mediated cyclization/ring opening cascade reaction of 1,2-nucloephilic addition adducts.Dienes type adducts can undergo simple Diels Alder reaction to afford fluorinated six-membered carboncycle.