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Anomeric sugar configuration of anthocyanin O ‐pyranosides determined from heteronuclear one‐bond coupling constants
Author(s) -
Pedersen Atle T.,
Andersen Øyvind M.,
Aksnes Dagfinn W.,
Nerdal Willy
Publication year - 1995
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.2800060608
Subject(s) - chemistry , anomer , heteronuclear molecule , coupling constant , peonidin , monosaccharide , anthocyanin , crystallography , stereochemistry , analytical chemistry (journal) , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , organic chemistry , cyanidin , physics , delphinidin , food science , particle physics
Using the nuclear magnetic resonance technique, two‐dimensional inverse heteronuclear shift correlation through multiple quantum coherence (HMQC), the one‐bond coupling constants between the carbon atoms and protons ( 1 J (C, H) ) have been measured for a number of anthocyanins represented by 6‐hydroxydelphinidin and all the common aglycones (except peonidin) and monosaccharides found as building blocks of anthocyanins. The large anomeric 1 J (C, H) values of rhamnopyranosyls (168‐170 Hz) show that these protons are in equatorial positions while the smaller 1 J (C, H) values of the other anomeric protons (162‐165 Hz) correspond to axial positions, thus assigning the anomeric configurations of the examined anthocyanins to be β for the gluco‐, galacto‐ and xylopyranosyls and α for the rhamno‐ and arabinopyranosyls. In the pentoses, xylo‐ and arabinopyranosyls, it was found that the 1 J (C, H) couplings for the equatorial H‐5 protons (149‐150 Hz) are larger than for the corresponding axial H‐5 protons (140‐143 Hz).