title: [The behavior of 1,4-benzodiazepine drugs in acidic media. XVI. Estimation of cis/trans isomer ratio of benzodiazepinooxazoles using nuclear magnetic resonance shift reagent].
abstract: The ratio of cis/trans isomers (referring to 11b-substituent and 2- or 3-substituent) of benzodiazepinooxazoles was estimated by using the lanthanide shift reagent (Eu(fod)3-d27) for nuclear magnetic resonance (NMR) spectroscopy. The amide carbonyl oxygen at 6-position is considered to coordinate with the reagent, because the largest downfield shifts were observed at the amide carbonyl carbon (C-6) in 13C-NMR and the amide hydrogen (H-7) in 1H-NMR. The ratios depend largely on the substituents at 11b-, 2-, and 3-positions. The cis isomer for compounds having 11b-hydrogen increases with an increase in the bulkiness of the substituents at 2-position. The cis isomer for compounds having 3-methyl group decreases with change from 11b-2'-chlorophenyl group (mexazolam) to 11b-hydrogen.
authors.affiliation: Department of Pharmacy, NTT Tokai General Hospital, Nagoya, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kuwayama
authors.forename: S
authors.initials: S
authors.lastname: Kato
authors.forename: Y
authors.initials: Y
authors.lastname: Kurono
authors.forename: K
authors.initials: K
authors.lastname: Hatano
authors.forename: T
authors.initials: T
authors.lastname: Hayazaki
authors.forename: T
authors.initials: T
authors.lastname: Yashiro
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
mesh_terms: D001569:Benzodiazepines / Q000737:chemistry*; D002725:Chloroform; D007202:Indicators and Reagents; D007536:Isomerism; D007811:Lanthanum; D009682:Magnetic Resonance Spectroscopy
chemical_list: D007202:Indicators and Reagents; D001569:Benzodiazepines; D007811:Lanthanum; D002725:Chloroform