Efficient and metal-free oxidation of 1,4-dihydropyridine and urazole derivatives with Poly-(4-vinylpyridinium nitrate) and Cellulose Sulfuric Acid.

An efficient and metal-free oxidative aromatization of alkyl or aryl-substituted derivatives of 1, 4-dihydropyridines and urazoles is studied using poly-(4-vinylpyridinium nitrate) in the presence of cellulose sulfuric acid. Th e reaction was carried out in 1-butyl-3-methylimidazolium chloride [bmim]Cl at room temperature and the products were isolated in good to excellent yields.