New Synthetic Approach for the Preparation of Imidazole N3-Oxide

Abstract: A new synthetic procedure of 1-alkyl(aryl)-1H-4-meth-ylimidazole N3-oxide derivatives by cyclocondensation of a-amine-oximes and orthoesters was studied. Low yields in the cyclization process were the result of predominant Z-stereoisomer around the oxime moiety of a-amineoxime reactants. Different attempts to im-prove these yields were assayed, mild conditions being those that produce the best results. Also, the special acidity of hydrogen-2 in the imidazole N3-oxide system was studied in solution by NMR spectroscopy. This property provides a convenient intermediate to access 2-substituted analogues