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

A simple, efficient and green approach to the synthesis of 1 H -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 H 2 O: PEG 400 = 6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method. Graphical abstract