Nitro and aminobenzimidazoles

Abstract

A summary of the preparation methods of 2 tautomeric and 4 N -methylated benzimidazoles with a nitro group on the benzene ring ( 1–6 ) and with an amino group in the same positions ( 7–12 ) were summarized. Annular tautomerism of the title compounds 1–12 has been studied using 1 H, 13 C and 15 N NMR spectra in liquid and solid state (CPMAS), UV spectra and quantum chemical calculations.