Claude Morat

Measurement of long-range heteronuclear couplings: Application to oligosaccharide conformation

3J(C,H) values have been measured using 2D-J heteronuclear-resolved n.m.r. spectroscopy to estimate interglycosidic conformations in various oligosaccharides with a degree of polymerization ranging from 6 to 30.

Study by 23Na-NMR, 1H-NMR, and Ultraviolet Spectroscopy of the Thermal Stability of an 11-basepair Oligonucleotide

23Na-NMR, (1)H-NMR, and ultraviolet (UV) spectroscopy have been used to study the thermal stability of the double helix structure of an 11-basepair oligonucleotide. The denaturation curves obtained by (23)Na-NMR and UV are analyzed using a two-state model. The melting temperature and DeltaH(0) obtained are identical within experimental error, suggesting that modifications in the ionic atmosphere, probed by (23)Na-NMR, and the modifications in the basepair stacking, probed by UV, occur at the same temperature. Additional dynamical information on the denaturation process has been obtained by (1)H-NMR: slow exchange is observed between the thymine methyl resonances, and the disappearance of imino protons shows that a single basepair opening does not contribute significantly to proton exchange.

Interglycosidic 13C-1H coupling constants: an approach to disaccharide conformations

Abstract Interglycosidic 13C-1H coupling constants have been measured for different saccharides by selective 2D-J heteronuclear n.m.r. spectroscopy.

Oxydation chromique de l'adamantanone : preparation de l'acetoxy-5 adamantanone-2

Abstract chromic oxidation of adamantanone gives adamantane-2,6-dione (20%), 5-hydroxy adamantan-2-one (6%) and 5-acetoxy adamantan-2-one (36%).

Synthesis of a nitro group containing ribonucleoside related to guanosine

Abstract The α- and β-anomers of the nitro group containing ribonucleoside 2 have been prepared in a three-step sequence. Both exhibit an intramolecular H-bond between the 4-NH and an oxygen atom of the nitro group.

Syntheses d'oxazolidines substituees par l'adamantane et de nitroxydes oxazolidines stables derives de l'adamantane

Abstract Adamantane oxazolidine derivatives have been prepared. The corresponding mono and biradicals have molecular shapes well suited to the study of the motion anisotropy in solution.