title: Nuclear magnetic resonance studies of the 4R and 4S diastereomers of spiroiminodihydantoin 2'-deoxyribonucleosides: absolute configuration and conformational features.
abstract: The present study was aimed at gaining further insights into stereochemical and conformational features of the 4R and 4S diastereomers of spiroiminodihydantoin 2'-deoxyribonucleosides that have been shown to be the predominant singlet oxygen oxidation products of 2'-deoxyguanosine in aqueous solutions. It may be added that spiroiminodihydantoin derivatives are efficiently generated by one-electron and singlet oxygen oxidation of the 8-oxo-7,8-dihydroguanine moiety of several nucleic acid components including nucleosides, nucleotides, and oligonucleotides. The reported structural data on the pair of diastereomeric spiroiminodihydantoin 2'-deoxyribonucleosides 1 and 2 are mostly inferred from extensive (1)H and (13)C NMR analyses including two-dimensional nuclear Overhauser effect measurements performed in both D(2)O and dimethyl sulfoxide. This approach that has been shown previously to be suitable to assign the stereochemistry of the base moiety of oxidized pyrimidine nucleosides was completed by molecular modeling and quantum mechanics studies. Thus, application of these two complementary approaches together with the consideration of the results of a recent relevant quantum mechanic study has allowed the assignment of the absolute stereoconfiguration of the C-4 carbon of diastereomers 1 and 2. In addition, information is provided on the conformational features of the 2-deoxyribose moiety and the orientation of the base around the N-glycosidic bond of both 2'-deoxyribonucleosides 1 and 2.
authors.affiliation: Laboratoire de Chimie Inorganique et Biologique, UMR-E No. 3 (CEA-UJF), Département de Recherche Fondamentale sur la Matière Condensée, CEA/Grenoble, F-38054 Grenoble Cedex 9, France.
authors.forename: Boleslaw
authors.initials: B
authors.lastname: Karwowski
authors.forename: François
authors.initials: F
authors.lastname: Dupeyrat
authors.forename: Michel
authors.initials: M
authors.lastname: Bardet
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Ravanat
authors.forename: Piotr
authors.initials: P
authors.lastname: Krajewski
authors.forename: Jean
authors.initials: J
authors.lastname: Cadet
mesh_terms: D002244:Carbon / Q000737:chemistry; D003853:Deoxyribonucleosides / Q000737:chemistry*; D006151:Guanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D003853:Deoxyribonucleosides; D013141:Spiro Compounds; C408822:spiroiminodihydantoin; D006151:Guanosine; D002244:Carbon