17O NMR of L-Ascorbic Acid. New Spectroscopy of an Old Molecule

✍ Scribed by A. Ruchmann; J. Lauterwein; T. Bäcker; M. Klessinger

• Book ID: 102652572
• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 603 KB
• Volume: 34
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199602)34:2<116::aid-omr854>3.0.co;2-l

✦ Synopsis

Natural abundance 1 7 0 NMR spectra of L-ascorbic acid were recorded in aqueous solution as a function of pH. The water solvent peak was suppressed through the use of 170-depleted water and inversion-recovery. The 1 7 0 NMR resonances were assigned from chemical shift comparison and pH titration behaviour. The resonance of the fl-enol oxygen could also be located because of its isotopic exchange with water. Charge densities and bond orders were calculated for a-hydroxytetronic acid at the 6-31G** SCF level. Their variations with pH related well with the 7O titration shifts in L-ascorbic acid.