The syntheses and biological evaluation of the first anti-protozoa imidazole N-oxide and benzimidazole N-oxide and their derivatives are reported. They were tested in vitro against two different protozoa, Trypanosoma cruzi and Trichomonas vaginalis. Derivative 7c, ethyl-1-(i-butyloxycarbonyloxy)-6-nitrobenzimid-azole-2-carboxylate, displayed activity on both protozoa. Lipophilicity and redox potential were experimentally determined in order to study the relationship with activity of the compounds. These properties are well related with the observed bioactivity. Imidazole and benzimidazole N-oxide derivatives are becoming leaders for further chemical modifications and advanced biological studies
