Oxidation of 1,4-Dihydropyridines under Mild and Heterogeneous Conditions Using Solid Acids

M.A. Zolfigol ^a,*, M. Bagherzadeh^b, K. Niknam^c,*, F. Shirini^d, I. Mohammadpoor-Baltork^e, A. Ghorbani Choghamarani^a and M. Baghbanzadeh^a

^aChemistry Department, College of Science, Bu-Ali Sina University, Hamadan 65174, Iran

^bCollege of Chemistry, Sharif University of Technology, Tehran, Iran

^cChemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75168 Iran

^dChemistry Department, College of Science, Guilan University, Rasht, Iran

^eChemistry Department, College of Science, Isfahan University, Isfahan, Iran

(Received 12 November 2005, Accepted 4 January 2006)

      A combination of solid acids, including Oxone^®, HIO₃, H₅IO₆, and polystyrenesulfonic acid and sodium nitrite, in the presence of wet SiO₂ were used as an effective oxidizing agents for the oxidation of dihydropyridines to their corresponding pyridine derivatives under mild and heterogeneous conditions in good to excellent yields.

Keywords: Oxidation, 1,4-Dihydropyridines, Pyridines, Solid acids