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Two-Dimensional Proton Chemical Shift Correlated NMR Spectroscopy of Digitoxose1
Titel:
Two-Dimensional Proton Chemical Shift Correlated NMR Spectroscopy of Digitoxose1
Auteur:
Coxon, Bruce
Verschenen in:
Journal of carbohydrate chemistry
Paginering:
Jaargang 3 (1984) nr. 4 pagina's 525-543
Jaar:
1984
Inhoud:
The hydroxyl proton coupled 1H NMR spectra of solutions of β-d-digitoxopyranose and of an equilibrated mixture of the four ring forms of d-digitoxose in dimethylsulfoxide-d6 have been assigned completely by two-dimensional, proton chemical shift correlated NMR spectroscopy and spin decoupling at 400 MHz. Analysis of resolution enhanced, one-dimensional 1H NMR spectra yielded an almost complete set of CH and OH proton-proton coupling constants for the four ring forms. The free aldehydo form of d-digitoxose in dimethylsulfoxide-d6 solution has been detected by means of its characteristic H-l quartet at 6 9.687. Quantitative analysis of the equilibrated mixture of the five forms of d-digitoxose gave the composition:- α-pyranose, β-pyranose, α-furanose, β-furanose, aldehydo form, 11.2, 67.3, 8.4, 13.0, and 0.1%, respectively. The 4C1 chair conformations have been assigned to the α- and β-pyranose forms by analysis of the coupling constants and are discussed qualitatively in terms of their relative stabilities.
Uitgever:
Taylor & Francis
Bronbestand:
Elektronische Wetenschappelijke Tijdschriften
Details van artikel 173 van 178 gevonden artikelen
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