Cobalt-based nanocatalyst catalyzed one-pot four-component synthesis 2H-indazolo[2,1-b]phthalazine-triones under solvent-free condition

In this research, an efficient procedure for the one-pot four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones catalyzed by a cobalt-based nanocatalyst (Co/Al₂O₃ nanocatalyst) is reported. The catalyst was prepared by a co-precipitation method and characterized by BET surface area, SEM, TEM, EDS and XRD analyses. A wide range of various aromatic aldehydes including electron-withdrawing and electron-releasing groups were applied and corresponding products obtained in high yields without any by-product. Moreover, the Co/Al₂O₃ is recyclable up to 7 consecutive runs by simple filtration.