title: Determination of the cation-chelating potential of C-methylthiolated beta-lactams and their sulfones by electrospray ionization mass spectrometry.
abstract: The chelation potential of highly lipophilic C-dimethylthiolated monocyclic beta-lactams was examined using electrospray ionization mass spectrometry (ESI-MS). The metal salts NaCl, KCl, CaCl2, ZnCl2, Cu(NO3)2, CdSO4, MnCl2, and Mg(NO3)2 were used for the analysis. The K+ adducts of the compounds studied were more responsive in ESI analysis, compared to their Na+ adducts, regardless of the oxidation state of the sulfur (in the methylthio or the sulfone groups) and the type of the group adjacent to the lactam carbonyl. Opening of the beta-lactam ring, leading to formation of a chargeable N-atom, had little to no effect on the K+ adduct formation. Interactions of the methylthio group with the divalent zinc ion were also observed.
authors.affiliation: Department of Chemistry, American University, 4400 Massachusetts Ave., NW, Washington, DC 20016, USA. mkonak@american.edu
authors.forename: Monika I
authors.initials: MI
authors.lastname: Konaklieva
authors.forename: Lita S
authors.initials: LS
authors.lastname: Suwandi
authors.forename: Maya B
authors.initials: MB
authors.lastname: Kostova
authors.forename: Jianghong
authors.initials: J
authors.lastname: Gu
mesh_terms: D002412:Cations / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D012996:Solutions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013450:Sulfones / Q000737:chemistry / Q000378:metabolism*; D014867:Water / Q000737:chemistry; D047090:beta-Lactams / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002412:Cations; D008670:Metals; D012996:Solutions; D013450:Sulfones; D047090:beta-Lactams; D014867:Water