A practical synthesis of functionalized pyrazoles promoted by a polyoxomolybdate-based iron catalyst

An efficient synthesis of pyrazole scaffolds from arylsulfonylhydrazines and diketones promoted by a molecular molybdenum oxide catalyst (NH₄)₃[FeMo₆O₁₈(OH)₆] is described. The iron-based polyoxometalate catalyst is heterogeneous, reusable with stable recyclability. Using this method, a wide range of arylsulfonylhydrazines and diketones can undergo smoothly condensation cyclization to produce functionalized pyrazoles in high yields.