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13 C NMR spectroscopy of substituted xanthones—II: 13C NMR spectral study of polyhydroxy xanthones

✍ Scribed by A.W. Frahm; R.K. Chaudhuri

Publisher
Elsevier Science
Year
1979
Tongue
French
Weight
385 KB
Volume
35
Category
Article
ISSN
0040-4020

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✦ Synopsis

&&act-The '%ZNMR chemical shifts of eleven hydroxy-, two hydroxymethoxy xanthones, and xanthone-C-gfucoside, mangiferin. arc presented and analyzed. Hydroxy substituent effects depending on substituent lxmition as well as on shielded ring carbon position have been evaluated. Hydroq substituent increments for xanthones arc proposed. Effccta of hydroxylation on carbonyl carbon shift and the methyl&ion of hydroxy group and the corresponding shift increments which are of diagnostic vslue have been observed and d&ussed.

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