Mild preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives with magnetic Fe3O4 nanoparticles coated by (3-aminopropyl)-triethoxysilane as catalyst under ambient and solvent-free conditions

An efficient, one-pot quantitative procedure for preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives from four-component condensation reaction of hydrazine monohydrate, phthalic anhydride, malononitrile or ethyl cyanoacetate, and aromatic aldehydes in the presence of magnetic Fe₃O₄ nanoparticles coated by (3-aminopropyl)-triethoxysilane as catalyst under mild, ambient, and solvent-free conditions is described. Simple procedure, high yield, short reaction time, and environmentally benign method are advantages of this protocol. The magnetic Fe₃O₄ nanoparticles coated by (3-aminopropyl)-triethoxysilane can be recovered and reused several times without loss of activity.