A variety of fully substituted pyrazoles were easily prepared through a three-component condensation of aldehydes, arylhydrazines, and ethyl acetoacetate in the presence of catalytic amounts of zinc triflate [Zn(OTf)2] under solvent-free conditions. Selective synthesis of symmetrical and unsymmetrical bispyrazoles from dialdehydes in high yields can be considered as a notable advantage of this method.
An efficient, rapid, and green synthesis of functionalized pyrazoles has been accomplished under solvent-freeconditions by the reaction of phenyl hydrazine, aldehydes and ethyl acetoacetate. This approach exploits the synthetic potential of microwave irradiation and scandium triflate combination and offers many advantages such as excellent product yields, shorter reaction time, easy isolation of products