title: 13C NMR discrimination of regioisomeric bispyrroloquinone/bispyrroloiminoquinone ring systems.
abstract: The structural assignment of bispyrroloquinone and bispyrroloiminoquinone regioisomers was achieved using (13)C NMR spectral data. In the case of bispyrroloiminoquinones, the carbonyl group in the regioisomer possessing a nitrogen atom in both alpha-positions was systematically less deshielded than the carbonyl group in the other regioisomer. In the case of bispyrroloquinones, the most deshielded carbonyl group in the regioisomer with a nitrogen atom in both alpha-positions was more deshielded than the same carbonyl group in the other regioisomer.
authors.affiliation: Université Paul Sabatier, UMR CNRS 5068, Laboratoire de Synthèse et Physicochimie de Molécules d'Intérêt Biologique, 118 Route de Narbonne, 31062 Toulouse Cédex 9, France.
authors.forename: Stefan
authors.initials: S
authors.lastname: Chassaing
authors.forename: Evelyne
authors.initials: E
authors.lastname: Delfourne
mesh_terms: D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D047608:Pyrroloiminoquinones / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D002247:Carbon Isotopes; D047608:Pyrroloiminoquinones