Synthesis and characterization of methyl substituted 3-hydroxypyridin-4-ones and their complexes with iron(III)

Methyl substituted 3-hydroxypyridin-4(1H)-ones have been synthesized. The pK(a) values and Fe3+ affinity constants of these ligands were studied. The introduction of an electron-donating methyl group at a different position of pyridinone ring markedly influences the pKa values of 3-hydroxy and 4-oxo groups. The pFe(3+) values were also affected and are in the range of 17.6-20.7. The findings can be used to guide a design of 3-hydroxypyridin-4-ones with desirable pK(a) and pFe(3+) values.