Solvent free one pot synthesis of amidoalkyl naphthols over phosphotungstic acid encapsulated montmorillonite clay catalysts

Montmorillonite KSF clay was effectively modified by the encapsulation of phosphotungstic acid into the clay layers via sonication followed by incipient wet impregnation method. The prepared catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The catalytic activities of the prepared systems were investigated in the solvent free synthesis of amidoalkyl naphthols by the multicomponent one-pot condensation of an aldehyde, β-naphthol and an amide or urea. Excellent yield, shorter reaction time, easy work-up, and reusability of the catalyst are the main attractions of this green procedure.