Facile and Efficient Synthesis ۲H-indazolo[۲,۱-b]phthalazine-trionesDerivatives Using Fe۳O۴/eggshell/CS@HSO۴ NPs as a heterogeneous andrecyclable nanocatalyst

In this paper, a facile and efficient method for the synthesis of ۲H-indazolo[۲,۱-b]phthalazinetrionesbased on the acid-catalyzed multicomponent reaction of dimedone, hydrazine, and phthalicanhydride with aldehydes reported in the presence of Fe۳O۴/eggshell/CS@HSO۴ in solvent-free.We have synthesized a new nanocomposite material in which eggshell membranes act asnucleation sites for the precipitation of Fe۳O۴/eggshell/CS@HSO۴ nanoparticles in the attendanceof an external magnetic field. In the next step anchoring a chlorosulfonic acid on the surface ofeggshell‐coated magnetic nanoparticles as solid waste was transformed into a magneticbiomaterial, green, cheap, and environmentally friendly catalyst (Fe۳O۴/eggshell/CS@HSO۴).Techniques such as FT-IR, VSM, FESEM, TEM, EDX, XRD, and TGA characterized the assynthesizedcatalyst. The catalytic property of the as-prepared catalyst was examined insynthesizing ۲H-indazolo[۲,۱-b]phthalazine-triones [۱-۳].