Study On The Transformations Of Arylhydrazines Through Heating/light-promotion Precedure

Arylhydrazines are not only one of the core skeletons existing in various natural products,drugs,polymers,dyes and agrochemicals,but also have the advantages of high reaction activity,low cost and easy availability.As important and widely used starting materials,arylhydrazines are not only used as nitrogen sources for the synthesis of nitrogen-containing compounds,but also employed as aryl sources for environment-friendly arylation reactions.Therefore,the research on the conversion and application of arylhydrazines is of great significance and has become one of the most popular research topics in recent years.This work mainly focuses on the one-step,green and effective synthesis of biologically active nitrogen-containing compounds including thiazoles,hydrazides,and 1,2,4-triazol-3-amines.These transformations were accomplished using inexpensive and available arylhydrazines as starting materials through the cleavage of N-N/N-H/C-H bonds under simple and mild reaction conditions.（1）Carbon sulfide is a kind of raw material with easy availability,low price and high reactivity,which is often used as a sulfur source for the construction of various organic sulfur compounds in organic chemistry and pharmaceutical chemistry.In this case,benzo[d]thiazole-2（3H）-thiones and benzo[d]thiazol-2（3H）-ones were directly constructed using arylhydrazines and CS₂ as reaction substrates at different reaction temperatures in the presence of DMSO.These reactions were performed in the absence of any external catalysts,transition metals,bases,ligands,and oxidants with high step economy.In addition,the reaction involved C-S/C-N bond formation and the intermolecular[3+2]annulation to provide the target compounds.（2）N,N-Disubstituted acyl hydrazides are useful synthetic building blocks as well as important pharmaceutical scaffolds in the fields of organo-pharmaceutical chemistry.Direct C（=O）-N-N bond formation represents one of the most effective strategies through cross-dehydrogenative coupling（CDC）process.We developed an efficient method for the divergent synthesis of N,N-disubstituted acyl hydrazides and their bromides from N,N-disubstituted hydrazines and aldehydes by photoredox-catalytic CDC reactions.This versatile protocol enabled the direct construction of C（=O）-N-N and C（sp²）-Br bonds simultaneously from available starting materials without prefunctionalization.This one-pot strategy showed the advantages of mild reaction conditions,high atom and step economy,high regioselectivity,as well as good functional group tolerance.In addition,the selected compounds exhibited potential antitumor activities as new chemical entities,thus showing potential applications in the field of new anticancer drugs research.（3）Cyano addition/C（sp³）-H cyclization has the advantages of rapid,high efficiency and environment-friendly.The readily available reaction substrates can be converted into various high-value nitrogen-containing heterocyclic compounds through this strategy.We developed an efficient cyano addition/C（sp³）-H cyclization cascade reaction to synthesize different substituted1,2,4-triazol-3-amines from arylhydrazines and N-Cyano-N-phenyl-p-methylbenzenesulfonamides（NCTS）,using Eosin Y as photocatalysts,potassium carbonate as a base in the presence of DMF/DMSO under visible light irradiation.The highlight of this strategy is the construction of two C=N bonds in one step without the addition of any metal photocatalysts and external oxidants.In addition,the reaction has the remarkable advantages of mild reaction conditions,good functional group tolerance and broad substrate scope.