Zn[(l)proline]2 in water: A new easily accessible and recyclable catalytic system for the synthesis of pyrazoles

Zn[(l)proline]2 has been found to be an efficient catalyst for the synthesis of pyrazole derivatives in pure water at room temperature. Reaction afforded moderate to excellent yield within a lesser time. Various pyrazoles which could not be prepared by other methods can be easily prepared by this method efficiently. Catalyst exhibits recyclability up to five runs. Hence our present protocol is economical and clean comprise of green reagent, solvent and catalyst.