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Carbon‐13 NMR spectroscopy of the biological pigments luteoskyrin and rugulosin and some polyhydroxyanthraquinone analogues
Author(s) -
Toma F.,
Bouhet J. C.,
Van Choung P. Pham,
Fromageot P.,
Haar W.,
Rüterjans H.,
Maurer W.
Publication year - 1975
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270071008
Subject(s) - chemistry , tautomer , intramolecular force , chemical shift , carbon fibers , nuclear magnetic resonance spectroscopy , carbon 13 nmr , spectroscopy , hydrogen bond , carbon atom , nucleic acid , photochemistry , organic chemistry , computational chemistry , molecule , ring (chemistry) , materials science , physics , quantum mechanics , composite number , composite material , biochemistry
The bianthraquinonic biological pigments luteoskyrin and rugulosin and five polyhydroxyanthraquinone derivatives are studied by carbon‐13 NMR in DMSO solution. Peak assignment for the fourteen carbon atoms of these compounds is achieved by proton spin decoupling and by investigating the effect of ionisation of the hydroxyl groups upon the carbon chemical shifts. Carbon chemical shifts in the planar hydroxyanthraquinones can be rationalised in terms of conjugation and intramolecular hydrogen bonding. The latter is responsible for the relative acidity of the hydroxyl groups in the analogues, and for the different conformations proposed for luteoskyrin and rugulosin. Tautomeric equilibria occur in DMSO and water–DMSO solutions for the anionic species [LS] 2− and [RG] 2− . This can account for the binding of luteoskyrin and rugulosin to nucleic acids.