Abstract A new, facile, and cost-effective process involving the solvent-free synthesis of amidoalkyl naphthols using a three-component, one-pot condensation reaction of β-naphthol, aromatic aldehyde, and amides in the presence of Al(H2PO4)3 as heterogeneous catalyst under thermal conditions and microwave irradiation has been described. This new approach has the advantage of consistently excellent
Zirconocene dichloride (Cp2ZrCl2) was found to be highly efficient catalyst for the synthesis of structurally diverse 1-amidoalkyl-2-naphthols by one-pot multi-component reaction (MCR) of 2-naphthol with a variety of aryl aldehydes and amides under ambient temperature. The activation of both carbonyl groups of aryl aldehydes and the o-quinine methide intermediate accounts for the high reactivity of Cp2ZrCl2.
Silica gel-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multicomponent condensation reaction of aryl aldehydes, 2-naphthol, and urea or amides to afford the corresponding 1-amidoalkyl-2-naphthols in good to excellent yields. This new approach consistently had short reaction times, high conversions, clean reaction profiles, and simple experimental and workup procedures.