A novel sulfamic acid functionalized nano-catalyst on the basis of calix[4]resorcinarene for the green one-pot synthesis of 2H-indazolo[2,1-b]phthalazine-triones under thermal solvent-free conditions

Abstract

N-propyl sulfamic acid supported nano-catalyst on the basis of calix[4]resorcinarene was prepared via the efficient and facile reaction of amine functionalized polycalix[4]resorcinarene with chlorosulfonic acid. The achieved catalytic system was characterized using some spectroscopic techniques such as Fourier transform Infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and CHNS elemental analysis. This newly developed acidic catalyst was employed efficiently in a one-pot three-component condensation reaction of aromatic aldehydes, dimedone and phthalhydrazide for the synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives through an easy and eco-friendly methodology. The catalyst was easily separated from the reaction mixture by simple filtration and the desired products were achieved in good to excellent yields in short reaction times.