A new simple method for the preparation of PbO nanoparticles and implementation of an efficient and reusable catalytic system for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones

Abstract: PbO nanoparticles were explored as a highly efficient, simple, cheap, and recyclable catalyst for the fast synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives by means of a one-pot three-component reaction of phthalhydrazide, aromatic aldehyde, and malononitrile under solvent-free conditions at 80 °C. Furthermore, nanosized PbO was prepared by the two conventional methods of planetary ball milling and dispersion of commercial PbO in n-octane, and their catalytic performances were compared with the commercial bulk PbO. The prepared nano-PbO via ball milling was described by SEM, TEM, XRD, EDX, and FT-IR spectroscopy. The present protocol conveyed major proficiencies such as the use of a reasonable and readily available catalyst, simple work-up and purification of products by nonchromatographic strategy, low reaction times, and enhanced yields under relatively environmental benign conditions. The heterogeneous catalyst was appropriately recyclable and could be reused for several times without loss of activity. Graphical Abstract: [Figure not available: see fulltext.].