Tautomery and acid-base properties of some azoderivatives of benzoylacetone

► ADB exist in solution as a mixture of enol-azo and hydrazo tautomeric forms. ► Tautomeric balance shifts to the enol-azo form an increase in the solvent polarity. ► Proton dissociation in ADB is unspontaneous, endothermic and entropically unfavorable.