Synthesis and study of prototropic tautomerism of 2-(3-chromenyl)-1- hydroxyimidazoles

Article abstract of DOI:10.1016/j.tet.2013.02.039

A series of novel derivatives of imidazole containing a chromenyl moiety in position 2 of the ring has been synthesized. A characteristic response of the chromenyl ring H-2 proton to its environment allows the study of the prototropic tautomerism of novel 1-hydroxyimidazoles in solution using ¹H NMR spectroscopy. It has been shown that the predominance of one or another tautomer depends on the nature of the substituents of the imidazole ring, and the proton-donating/proton-withdrawing properties of a solvent. X-ray diffraction data for two of the compounds has revealed that in the solid state these 1-hydroxyimidazole derivatives exist as N-oxide tautomers.