Silica sulfuric acid promoted aromatization of 1,2-dihydroquinolines by using NaNO2 as oxidizing agent under mild and heterogeneous conditions

A combination of silica sulfuric acid (SSA) and NaNO2 in the presence of wet-SiO2 were used as an effective oxidizing agent for the oxidation of 1,2-dihydroquinolines to their corresponding quinoline derivatives in dichloromethane at room temperature with excellent yields.