THE AMPHIONIC STRUCTURE OF 3-HYDROXY-2-METHYL-4H-PYRAN-4-ONE AND THE PROPERTIES OF ITS COMPLEXES WITH IRON IONS

3-Hydroxy-2-methyl-4H-pyran-4-one (I), in aqueous solutions may assume depending on their pH-IH+ form at pH <1, I- at pH> 7 and I+/- at pH = 5.5. Considering pH(i) = 5.5 the value of K(a1) = 10(-2.3) correspond ing to IH+ half arrow right over half arrow left I couple was calculat ed. The compound I forms with Fe2+ and Fe3+ ions at a pH = 5.5 in aero bic conditions a mixture of complexes containing both Fe3+ and Fe2+ an d thus it controls the Fe2+ half arrow right over half arrow left Fe3 equilibrium. These complexes (dissolved in CHCl3) are stable against H2O2 and a series of compounds of biological relevance (amino acids, h ydroxyacids, proteins, enzymes, etc.)