Study On The Electrocatalytic Synthesis Of Fully Substituted Sulfonyl Pyrazole Compounds

Pyrazole and its derivatives are a class of five membered nitrogen heterocyclic compounds.Because of their antibacterial,anti-cancer,anti-inflammatory,anti proliferation and other biological activities,they have been widely used in pharmaceutical chemistry and agricultural chemistry.In this paper,under the condition of no metal,no external oxidant and TBAI as catalyst,totally substituted sulfonylpyrazole was synthesized by electrocatalysis of1,3 aryl(alkyl)diketones and aryl sulfonyl hydrazides,in which aryl sulfonyl hydrazides were used as ring components and sulfonyl radical precursors.By choosing different electrochemical reaction conditions,1,3-aryl(alkyl)diketone can react with aryl sulfonyl hydrazides to obtain corresponding fully substituted sulfonylpyrazole.Moreover,this method also can be readily applied to gram-scale preparation.The mechanism study showed that the electrochemical cascade reaction of all substituted sulfonylpyrazole was carried out through the sequence of intermolecular condensation,free radical cross coupling sulfonylation and pyrazole cyclization.