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Room‐temperature ( 1 H, 13 C) and variable‐temperature ( 1 H) NMR studies on spinosin
Author(s) -
Lewis K. C.,
Maxwell A. R.,
McLean S.,
Reynolds W. F.,
Enriquez R. G.
Publication year - 2000
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/1097-458x(200009)38:9<771::aid-mrc729>3.0.co;2-4
Subject(s) - chemistry , heteronuclear single quantum coherence spectroscopy , conformational isomerism , proton nmr , two dimensional nuclear magnetic resonance spectroscopy , carbon 13 nmr , stereochemistry , organic chemistry , molecule
Spinosin, a C ‐glycoside flavonoid, was isolated from the plant Desmodium tortuosum (Sw.) DC. The 1 H and 13 C NMR data acquired at room temperature exhibited doubling of signals, suggesting the presence of two rotamers in solution. Variable‐temperature 1 H NMR experiments confirmed this hypothesis. T‐ROESY experiments in conjunction with theoretical (MM2) calculations supported the proposal that the two rotamers interchange via rotation about the C‐6— C‐1′′ bond. The spectral data were completely assigned using 1 H– 1 H COSY, HMQC, HSQC and HMBC experiments. Copyright © 2000 John Wiley & Sons, Ltd.