Chiroptical detection during liquid chromatography, part 5: On-line measurement of circular dichroism spectra ??(?) during stops of chromatographic flow

Brandl, G.; Kästner, Fritz; Fritsch, Rainer; Zinner, H.; Mannschreck, Albrecht

doi:10.1007/bf00810937

Cited by 17 publications

(2 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the hyphenation of CD measurements with HPLC techniques has been known for several years, [6][7][8][9] applications are still rare and mainly concern the measurement of isomerization barriers of configurationally unstable known compounds or the determination of the elution order of enantiomers of given (known) chiral substances on a chiral phase, e.g., of drugs. 10 So the introduction of this methodology for the determination of the absolute configuration of new compounds-and not only natural ones-directly from a crude mixture is a rewarding goal.…”

Section: Introductionmentioning

confidence: 99%

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

et al. 2008

View full text Add to dashboard Cite

The application of modern online methods, e.g., HPLC-MS/MS and HPLC-NMR, allows the elucidation of constitutions and relative configurations of new natural products directly from crude extracts. To additionally establish the full absolute configurations of such secondary metabolites without the necessity of first isolating the compounds, we have introduced HPLC-CD coupling (CD = circular dichroism) into natural product analysis, taking advantage of the different chiroptical properties of stereoisomers, in particular of enantiomers. In combination with quantum chemical CD calculations this method allows the stereochemical characterization of (even structurally unprecedented) chiral molecules, thus avoiding the--often risky--merely empirical assignment by comparison with the CD spectra of related compounds with known absolute stereostructures, or by other methods such as, e.g., the exciton chirality approach. This review presents the experimental requirements for the hyphenation and the theoretical background of the calculation of UV and CD spectra, which is then exemplified by some recent HPLC-CD applications to the elucidation of absolute configurations of most diverse compounds of mainly natural origin.

show abstract

Section: Introductionmentioning

confidence: 99%

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The application of CD spectroscopy, however, usually requires pure compounds. Although the on-line coupling of liquid chromatography with chiral detectors is well-known, − applications are still rare, while in the field of phytochemical analysis virtually no work in this direction has been done at all. In the past, detectors based on optical rotation dispersion (ORD) have mainly been used for this purpose. , Because of the operation principle, which is based on refractive index differences between right and left circularly polarized light, there are some limitations which include low sensitivity and the lack of compatibility with gradient elution.…”

mentioning

confidence: 99%

HPLC−CD On-Line Coupling in Combination with HPLC−NMR and HPLC−MS/MS for the Determination of the Full Absolute Stereostructure of New Metabolites in Plant Extracts

et al. 1999

View full text Add to dashboard Cite

The applicability of on-line coupling of gradient eluted nonchiral reversed-phase high-pressure liquid chromatography (HPLC) to circular dichroism (CD) spectroscopy for the stereochemical analysis of crude plant extracts was investigated. A detector measuring simultaneously UV absorbances and CD effects at constant wavelengths in the same detection cell was used. The solvent system water/acetonitrile was found to be suited to give high-quality CD chromatograms as a function of the elution time and even complete characteristic CD spectra in the stop-flow mode. The method was applied to the tropical liana Habropetalum dawei (Dioncophyllaceae). First, the extract solution was investigated by the combined application of HPLC−NMR and HPLC−ESI-MS/MS techniques. The constitution and relative configuration of two as yet unknown natural products thus detected, the isoquinoline phylline (5) and the naphthylisoquinoline alkaloid 5‘-O-methyldioncopeltine A (6), were characterized. Subsequent HPLC−CD experiments permitted the deduction of the absolute configurations of these new metabolites by empirical analysis of their CD data. Thus, using identical sample solutions and chromatographic conditions (including the same columns and solvent gradient programs), the combination of NMR, MS, and CD data permitted the complete structural elucidation of the two new metabolites in the extract matrix solution, without any isolation and sample purification prior to the coupling experiments.

show abstract

Spirobinaphthopyrans: Synthesis, x-ray crystal structure, separation of enantiomers, and barriers to thermal racemization

et al. 1999

View full text Add to dashboard Cite

Chiroptical detection during liquid chromatography, part 5: On-line measurement of circular dichroism spectra ??(?) during stops of chromatographic flow

Cited by 17 publications

References 21 publications

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

HPLC−CD On-Line Coupling in Combination with HPLC−NMR and HPLC−MS/MS for the Determination of the Full Absolute Stereostructure of New Metabolites in Plant Extracts

Spirobinaphthopyrans: Synthesis, x-ray crystal structure, separation of enantiomers, and barriers to thermal racemization

Contact Info

Product

Resources

About