title: Multinuclear NMR and FTIR studies of new polyoxaalkyl esters of lasalocid and their complexes with lithium and sodium cations.
abstract: Three new polyoxaalkyl esters of lasalocid are synthesized. Their ability to form complexes with Li(+) and Na(+) cations is studied using multinuclear NMR methods, FTIR spectroscopy in the middle and far IR regions, and mass spectrometry. It is found that lasalocid esters form only 1:1 complexes with the metal cations. The results of the NMR study in pyridine show that the polyoxaalkyl chain of the ester does not influence the complex formation of the lasalocid part of the esters. The reason for this is the competition of the pyridine molecules in the complexation process of metal cations. In chloroform the properties of the complex formation have changed and the oxaalkyl chain plays an important role within the complexation process, as demonstrated by the dependence of the respective continuous absorptions in the far IR region on the length of the oxaalkyl chain (i.e., on the number of the oxygen atoms in the chain). The modifications of the lasalocid molecule influences the complexation of the metal cation and probably the interactions with the membrane. An increase in antibiotic activity is found as a consequence of these changed interactions.
authors.affiliation: Department of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland.
authors.forename: Radosław
authors.initials: R
authors.lastname: Pankiewicz
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Schroeder
authors.forename: Błazej
authors.initials: B
authors.lastname: Gierczyk
authors.forename: Bogumił
authors.initials: B
authors.lastname: Brzezinski
authors.forename: Franz
authors.initials: F
authors.lastname: Bartl
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002412:Cations; D004952:Esters / Q000737:chemistry; D006860:Hydrogen Bonding; D066298:In Vitro Techniques; D007832:Lasalocid / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D011091:Polyesters / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects; D013816:Thermodynamics
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D004952:Esters; D046911:Macromolecular Substances; D011091:Polyesters; D008094:Lithium; D012964:Sodium; D007832:Lasalocid