The pyrazole moiety is widely regarded as a privileged heterocyclic skeleton with broad pharmaceutical activities,including antitumor,antifungal,and inhibitory activities.Substituted pyrazoles have also been utilized as useful ligands for metal-catalyzed cross-coupling reactions.Therefore,the development of a highly efficient and regioselective method would be greatly valuable for the synthesis of polyfunctionalized pyrazoles from easily available substrates.Herein,a novel three-component reaction is presented for the synthesis of polysubstituted pyrazoles from simple arylglyoxal monohydrates,tosylhydrazine,and aldehydes with excellent regionselectivity under mild conditions.