Zinc–proline complex as a novel and efficient catalyst for the green synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones.

A simple, efficient and green approach to the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones has been developed via one-pot three-component reaction of aromatic aldehyde, malononitrile and phthalhydrazide catalyzed by zinc–proline complex (Zn[L-proline]₂) using H₂O: PEG₄₀₀ = 6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method. [ABSTRACT FROM AUTHOR]