title: Structural isomer differentiation of 1,6-diaza-3,8-dioxabicyclo[4.4.1]undecane and N,N'-methylenebis(oxazolidine) by mass spectrometry.
abstract: The title compound types are structural isomers. The absence of literature studies dealing with the mass spectrometric gas-phase behavior of such compounds prompted a search for the best conditions for differentiation between the two prototype examples (R,R)-5,10-diphenyl-1,6-diaza-3,8-dioxabi-cyclo[4.4.1]undecane and N,N'-methylenebis[(R)-4-phenyloxazolidine]. Attempts to differentiate between the isomers by NMR were inconclusive and X-ray crystallography had to be used. The best mass spectrometric results were obtained using gas-phase ionization techniques, particularly chemical ionization, whereby protonated molecules were observed. The fragmentation pathways were elucidated from MS/MS studies and from experiments performed on hexadeuterated samples of each compound.
authors.affiliation: Laboratoire de Spectrométrie de Masse de l'Université R. Descartes, UMR 8638, Faculté de Pharmacie, 4 Avenue de l'Observatoire, 75270 Paris Cedex 06, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Monnier
authors.forename: Francine
authors.initials: F
authors.lastname: Libot
authors.forename: David J
authors.initials: DJ
authors.lastname: Aitken
authors.forename: Henri-Philippe
authors.initials: HP
authors.lastname: Husson
authors.forename: Denis
authors.initials: D
authors.lastname: Lesage
authors.forename: Françoise
authors.initials: F
authors.lastname: Fournier
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Tabet
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D007202:Indicators and Reagents; D010080:Oxazoles / Q000737:chemistry*; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012997:Solvents; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: C451494:5,10-diphenyl-1,6-diaza-3,8-dioxabicyclo(4.4.1)undecane; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007202:Indicators and Reagents; C451495:N,N'-methylenebis(oxazolidine); D010080:Oxazoles; D011522:Protons; D000644:Quaternary Ammonium Compounds; D012997:Solvents