13/ Februar 2007
HPLC-CD On-Line Coupling in Combinationwith HPLC-NMR and HPLC- MS/MS for theDetermination of the Full AbsoluteStereostructure of New Metabolites in PlantExtracts
Gerhard Bringmann, Kim Messer, Michael Wohlfarth, Jürgen Kraus, KarifalaDumbuya and Markus RückertInstitut für Organische Chemie der Universität Würzburg, Am Hubland, D-97074Würzburg
Analytical Chemistry, Vol. 71, No. 14, 1998, 2678-2686
The applicability of on-line coupling of gradient eluted nonchiral reversed-phaseHPLC to circular dichroism (CD) spectroscopy for the stereochemical analysis ofcrude plant extracts was inevestigated. The HPLC-system used was a PU-980iternary gradient pump, equipped with a CD-995 circular dichroism chiral detector,simultaneously monitoring the UV and CD signal at one specific wavelength andeven complete characteristc CD spectra in the stop-flow mode.The constitution and relative configuration of two yet unknown natural products, theisoquinoline phylline and the naphthylisoquinoline alcaloid 5`-O-methyldioncopeltineA, were characterized.Subsequent HPLC-CD experiments permitted the deduction of the absoluteconfigurations of their CD data. Thus in combination with other analytical techniques,as NMR and MS, CD spectra permitted the complete structural elucidation of the twometabolites, without any isolation and sample purification prior to the couplingexperiments.
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