A Facile Approach for One-Pot Synthesis of 1H-pyrazolo [1,2-b]phthalazine-5,10-dione Derivatives Catalyzed by ZrCl4 as an Efficient Catalyst Under Solvent-Free Conditions

A simple synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives via one-pot four-component condensation reaction of phthalimide, hydrazine monohydrate, aromatic aldehyde derivatives and malononitrile in the presence of a catalytic amount of zirconium tetrachloride (ZrCl4) as a mild and efficient Lewis acidic catalyst under thermal and solvent-free conditions with good yields and short reaction times is developed. This present methodology has notable benefits such as high efficiency, inexpensive and non-toxic catalyst, environmentally benign nature, solvent-free conditions and simplicity of operation.