Studies On The Synthesis Of Sulfonyl Pyrazoles And Thiosulfonates Involving Sulfonyl Hydrazines

Sulfonyl hydrazides have been widely used in organic synthesis as a substitute for sulfinic acid and its salts or sulfonyl halides in recent years.And they mainly participate in organic chemical reactions through the following ten pathways:（1）[RO₂S·],（2）RO₂SSR,（3）[Ar S·],（4）[RO₂S^-],（5）RSO₂-[Metal]species,（6）Ar-[Metal]species,（7）RSX,（8）RS-DBU,（9）nucleophilic amino group,（10）as diazene or sulfinic acid surrogate.Under the conditions of heat,alkalinity,oxidation,free radicals and transition metal catalysis,hydrazine groups can easily be removed from sulfonyl hydrazides.In addition,some carbon-sulfur bonding reactions have been successfully applied in the construction of carbon rings,heterocycles,and stereocenters.The purpose of this thesis is to introduce the synthesis of sulfonyl pyrazoles and thiosulfonates with sulfonyl hydrazides.This thesis is mainly divided into the following four chapters:Chapter 1 Research progress on the reaction of sulfonyl hydrazides in organic synthesisIn this chapter,the research progress of sulfonyl hydrazides in organic synthesis is reviewed in detail from three aspects:research progress of organic synthesis involving sulfonyl hydrazides light,heat,and electricity mediated.Chapter 2 Synthesis of sulfonyl pyrazoles under electrochemical conditionsA new synthesis method of 18 sulfonyl pyrazoles at room temperature is developed with acetonitrile and water as mixed solvent,tetrabutylammonium tetrafluoroborate as electrolyte,C as anode Pt as cathode,with 72-91%yield.The economical steps,simple operation,cheap reagents,good functional group tolerance and mild reaction conditions make this novel and effective strategy very useful.Chapter 3 Iodine promoted CS₂ mediated sulfonylation reaction involving aryl diazonium saltsA mild and rapid method for constructing thiosulfonates without using metal catalysts are developed.This method uses sulfonyl hydrazide as the raw material,CS₂and diazonium salt as the aryl sulfur source,iodine as the catalyst,and TBHP as the oxidant to construct a series of asymmetric thiosulfonates with a maximum yield of82%.The reaction is simple,high yielding,scalable,and proceeds smoothly with wide substrate scope and good functional group tolerance.Chapter 4 Summary and perspectiveThis thesis mainly focuses the synthesis of sulfonyl pyrazoles and thiosulfonates with the participation of sulfonyl hydrazides.3,5-dimethyl-1-toluenesulfonyl-1H-pyrazole and S-（4-methoxyphenyl）4-methylbenzenesulfonate are synthesized under two different reaction conditions respectively.The first part mainly introduces the synthesis of sulfonyl pyrazoles by sulfonyl hydrazides under electrochemical conditions,and the sulfonyl group is not removed.The second part introduces the combination of sulfonyl hydrazides as sulfonyl sources and aryl diazonium salts,CS₂generated aryl sulfur free radicals to generate thiosulfonates.Both reactions have mild reaction conditions,simple experimental operation,wide substrate range,and can obtain the target product with good yields.In future work,we will continue to explore the organic chemical reactions involving sulfonyl hydrazide.