An Efficient Method for the Oxidation of 1,4-Dihydropyridines under Mild and Heterogeneous Conditions via in Situ Generation of NOCl †

Abstract

A combination of inorganic chloride salts [e.g. AlCl₃, ZrCl₄, and ZnCl₂] and sodium nitrite in the presence of wet SiO₂ was used as an effective oxidising agent for the oxidation of dihydropyridines to their corresponding pyridine derivatives under mild and heterogeneous conditions in moderate to excellent yields.