title: Benzyl ions from 1,1-(2,2'-dimethoxyphenyl)-substituted 2-methylpropanes under electron ionization.
abstract: The electron ionization (EI)-induced fragmentations of a series of 1,1-(2,2'-dimethoxyphenyl)-substituted 2-methylpropanes (1-20) in both 70 eV and mass-analyzed ion kinetic energy (MIKE) spectra have been investigated. The EI-MS spectra of these compounds are characterized by the presence of abundant benzyl ions. These ions result from competitive hydrogen migration from the 2- and 2'-methoxy groups on the carbenium center of the diphenylmethyl cations formed by benzylic cleavage of the molecular ions. The relative abundances of the benzyl ions arising from such competitive processes are discussed and rationalized. The steric effect of the 3- or 3'-substituents is the main discriminating factor between the two competitive processes. The structural information, arising either from the 70 eV or the MIKE spectra, is discussed.
authors.affiliation: Dipartimento di Chimica e Tecnologie Farmaceutiche, Università di Palermo, via Archirafi 32, I-90123 Palermo, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Bongiorno
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Ceraulo
authors.forename: Felice
authors.initials: F
authors.lastname: Filizzola
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Fontana
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: Natoli
mesh_terms: D001593:Benzyl Compounds / Q000737:chemistry*; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D011407:Propane / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D001593:Benzyl Compounds; D006846:Hydrocarbons, Halogenated; D006859:Hydrogen; D011407:Propane