title: Gas-phase fragmentation of protonated benzodiazepines.
abstract: Protonated 1,4-benzodiazepines dissociate in the gas phase by the common pathway of CO elimination and by unique pathways dictated by the substituents; the latter typically differentiate one benzodiazepine from another. Protonated 3-dihydro-5-phenyl-1,4-benzodiazepin-2-one, the base diazepam devoid of substituents, dissociates by eliminating CO, HNCO, benzene, and benzonitrile. Mechanisms of these reactions are proposed with ionic products being resonance stabilized. The abundant [MH-CO]+ ion dissociates to secondary products via elimination of benzene, benzonitrile, the NH2 radical, and ammonia, yielding again ionic products that are stabilized by resonance.
authors.affiliation: Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Antonella
authors.initials: A
authors.lastname: Risoli
authors.forename: Joey B Y
authors.initials: JB
authors.lastname: Cheng
authors.forename: Udo H
authors.initials: UH
authors.lastname: Verkerk
authors.forename: Junfang
authors.initials: J
authors.lastname: Zhao
authors.forename: Gaetano
authors.initials: G
authors.lastname: Ragno
authors.forename: Alan C
authors.initials: AC
authors.lastname: Hopkinson
authors.forename: K W Michael
authors.initials: KW
authors.lastname: Siu
mesh_terms: D001569:Benzodiazepines / Q000032:analysis / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005740:Gases / Q000032:analysis / Q000737:chemistry*; D044367:Phase Transition; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D005740:Gases; D011522:Protons; D001569:Benzodiazepines