Green synthesis of 1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile derivatives using a new bifunctional base–ionic liquid hybrid magnetic nanocatalyst

The ionic liquid-base N,N,2,2,6,6-hexamethyl-N-(3-(trimethoxysilyl)propyl)piperidin-4-amonium iodide was grafted onto titana-coated NiFe₂O₄ nanoparticles for obtaining an efficient and reusable ionic liquid-base hybrid nanocatalyst. The structure of hybrid nanoparticles was characterized using FT-IR (Fourier-transform infrared spectroscopy), field emission scanning electron microscopy, EDS (energy-dispersive X-ray spectroscopy), EDS map scan, Brunauer–Emmett–Teller surface area analysis, CHN (elemental analysis), vibrating sample magnetometer and thermogravimetric analysis techniques. Furthermore, this novel hybrid catalyst was used in one-pot three-component synthesis of 3-amino-1-aryl-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile derivatives under green and environmentally benign conditions. This protocol avoids the use of harmful catalysts, toxic solvents and harsh reaction conditions. The products were synthesized in excellent yields within short reaction time and identified using elemental analysis, FT-IR, ¹H NMR and ¹³C NMR spectroscopies.