Tandem oxidative amidation of alcohols catalyzed by copper modified well-ordered mesoporous graphitic carbon nitride

Abstract

A novel and efficient protocol for tandem oxidative amidation of alcohols to amides with copper modified well-ordered mesoporous graphitic carbon nitride (Cu/g-C3N4) as a highly beneficial heterogeneous catalyst has been introduced. The conversion of substituted benzyl alcohols to various amides can be efficiently carried out with amine hydrochloride salts via one-pot direct oxidative amidation reaction using tert-butyl hydroperoxide (TBHP) as a green oxidant in acetonitrile. The desired amides were afforded with high to moderate yields and the excellent yield of the corresponding amides (93%) was obtained in the presence of 20 mg of Cu/g-C3N4 at 80 °C under N2 atmosphere for about 4 h. Notably, the one-pot tandem reaction have several outstanding advantages including facile synthetic method, excellent activity, acceptable reusability, eco-friendly nature and simple work-up. The Cu/g-C3N4 was prepared through a simple procedure and characterized by FT-IR, XRD, EDS, UV–vis, DRS, FE-SEM, ICP-OES, N2 adsorption spectroscopy. It is noteworthy that, the oxidative amidation of alcohols was progressed with only 4.36 wt% of copper species on the surface of graphitic carbon nitride.