title: Synthesis and evaluation of the complex-forming ability of hydroxypyranones and hydroxypyridinones with Ni (II) as possible inhibitors for urease enzyme in Helicobacter pylori.
abstract: The complex-forming ability of 2-methyl-3-hydroxypyran-4-one (1a), 2-ethyl-3-hydroxypyran-4-one (1b), 1,2-dimethyl-3-hydroxypyridin-4-one (4a) and 1-ethyl-2-methyl-3-hydroxypyridin-4-one (4b) with nickel(Ni(II)) were characterized by infrared, ultraviolet, proton nuclear magnetic resonance spectroscopy and melting point. The mole-ratio of nickel:ligands was analyzed by atomic-absorption-spectrometry. The partition-coefficients (KOW) of the compounds were also determined. The binding of ligands with Ni(II) are through deprotonated hydroxyl group (-O(-), disapeared at 3259 cm(-1)) and ioan-pairs of carbonyl group (=CO(.), shifted from 1650 to 1510-1515 cm(-1)). The characterization of complex geometry for bis-(2-methyl-3-hydroxypyranonato)Ni(II) (5a) and bis-(2-ethyl-3-hydroxypyranonato)Ni(II) (5b) predicted to be square-planer while for bis-(1,2-dimethyl-3-hydroxypyridinonato)Ni(II) (5c) and bis-(1-ethyl-2-methyl-3-hydroxypyridinonato)Ni(II) (5d) distorted to tetrahedral-geometry. Inhibitors of Helicobacter pylori urease are nickel chelators. The compounds 1a, 4a and 4b are likely suitable ligands with complex forming-ability to make complexes of 5a, 5c and 5d with nickel. The KOW values show the compound 5c with low partition-coefficient is more suitable ligand with lower penetration from GI lumen. Future studies demand to find out the biological activity of developed compounds on H. pylori.
authors.affiliation: Department of Clinical Biochemistry and Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, I.R. Iran.
authors.forename: Abbasali
authors.initials: A
authors.lastname: Palizban
authors.affiliation: Department of Medicinal Chemistry and Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, I.R. Iran.
authors.forename: Lotfollah
authors.initials: L
authors.lastname: Saghaie
keywords: 3-Hydroxypyran-4-one; 3-Hydroxypyridin-4-one; Helicobacter pylori; Nickel(II) complexes