title: Structural characterization of a new class of penem beta-lactam antibiotics by triple quadrupole tandem mass spectrometry.
abstract: A series of new penem beta-lactam antibiotics, having at position 2 of the thiazoline ring an amido-substituted amino acid moiety spaced by a methylene group, was analyzed by collisionally activated dissociation (CAD) tandem mass spectrometry on a triple-quadrupole mass spectrometer, after ionization by cesium ion bombardment. This approach allowed complete structural characterization without any matrix interferences. All the compounds investigated underwent beta-lactam ring cleavage through a typical retro-Diels-Alder reaction, as well as cleavage of the 2-side chain at two different points, with charge retention on both sides of the molecule. Subsequent fragmentation reactions essentially involved combinations of the above processes.
authors.affiliation: A. Menarini SRL, Chemical Research Department, Florence, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Triolo
authors.forename: F
authors.initials: F
authors.lastname: Bonelli
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D015780:Carbapenems / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems