Here, the application of guanidine supported on magnetic nanoparticles Fe3O4 (MNPs-guanidine) as a novel magnetically separable base nanocatalyst is described. We have investigated the application of this new catalyst for the synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives from the three-component, one-pot condensation reaction of phthalhydrazide, cyclic 1,3-dicarbonyl, and aromatic aldehydes under solvent-free conditions. The products were obtained in short reaction times with good to high yields. The supported catalyst could be simply separated and recovered from the reaction mixture with the assistance of an external magnet and reused 18 times with little loss of activity.
