Mild combination of nitro urea, derived from urea nitrate, and silica sulfuric acid (SiO(2)OSO(3)H) might act as an efficient oxidizing media, which could be able to oxidize different types of heterocyclic compounds including urazoles and 1,4-dihydropyridines. The process presented here is operationally simple, environmentally benign, and reactions have been mildly carried out in dichloromethane at room temperature.
