A variety of dipyrazolylmethane derivatives were synthesized from the reactions of readily available β-keto esters with arylhydrazine hydrochlorides and DMF in the presence of p-toluenesulfonic acid (p-TsOH). This methodology provides a concise and practical one-pot route for the construction of diverse dipyrazolylmethane derivatives in good yield. As an application, the synthesized nitro-substituted compound displayed an excellent turn-off fluorescence sensing property for the detection of Cu2+ ions.
