synthesis and evaluation of the complex-forming ability of hydroxypyranones and hydroxypyridinones with ni (ii) as possible inhibitors for urease enzyme in helicobacter pylori

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 (k ow ) 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 k ow 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 .