Synthesis and study of prototropic tautomerism of 2-(2-hydroxyphenyl)-1-hydroxyimidazoles

Abstract Novel 2-(2-hydroxyphenyl) substituted imidazoles have been synthesized. A prototropic tautomerism of the 1-hydroxyimidazole derivatives has been studied. X-ray diffraction analysis and IR-spectroscopy have revealed that in the solid state the title compounds exist as the N -hydroxy tautomers. The 1 H and 13 C NMR spectra of the new imidazole derivatives are discussed. It has been shown that in chloroform solutions 5-carbonyl substituted 2-(2-hydroxyphenyl)-1-hydroxyimidazoles exist in the N -hydroxy tautomeric form. A transition to DMSO results in the existence of the 1-hydroxyimidazoles under study as the N -oxide tautomers.