Topic
Xanthone
About: Xanthone is a research topic. Over the lifetime, 1639 publications have been published within this topic receiving 25870 citations. The topic is also known as: 9-oxo-xanthene & Diphenyline ketone oxide.
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TL;DR: A new prenylated xanthone, butyraxanthone F (1) together with 20 known compounds were isolated from the leaves of Pentadesma butyracea as discussed by the authors.
15 citations
TL;DR: This study represents a first approach to the systematic investigation of the reactivity of α-mangostin and describes the semisynthesis of some minor xanthones isolated from G. mangostana.
15 citations
TL;DR: A new xanthone, 1,4,8-trihydroxyxanthone (1 4 8 trihydroxy-9H-xanthen-9one), was isolated from the roots of Vismia latifolia (Guttiferae).
Abstract: A new xanthone,1,4,8-trihydroxyxanthone (1,4,8-trihydroxy-9H-xanthen-9-one), was isolated from the roots of Vismia latifolia (Guttiferae). Four other known xanthones were isolated: 1,5-dihydroxy-8-methoxyxanthone, 1,7-dihydroxyxanthone, 1,6-dihydroxy-7-methoxyxanthone and 1,3,5,6-tetrahydroxyxanthone. The last two compounds were isolated for the first time from a Vismia species. The structures were established by UV, IR, MS, 1D and 2D NMR spectroscopic techniques.
15 citations
TL;DR: In this paper, the mechanism of free-radical formation was established using the laser flash photolysis, and the photoinitiation ability of the xanthone or thioxanthone-derivative/ amino acid or sulfur-containing amino acid pairs depends on the initiator and co-initiator properties.
Abstract: Photoredox pairs, composed of xanthone or thioxanthone derivatives acting as light absorbers and tetrabutylammonium salts of amino acids or sulfur-containing amino acids as co-initiators, were studied as photoinitiators for free-radical polymerization. The mechanism of free-radical formation was established using the laser flash photolysis. Measurements of polymerization kinetics show that the photoinitiation ability of the xanthone- or thioxanthone-derivative/ amino acid or sulfur-containing amino acid pairs depends on the initiator and co-initiator properties, mostly on the triplet state lifetime of xanthone or thioxanthone derivatives.
15 citations
TL;DR: In this paper, a new xanthone C-glycoside, named homomangiferin, C19H17O10 (OCH3)·1.5H2O, decomposing over 250° without melting, [α]14D+8.7° (pyridine), was isolated from crude mangiferin obtained from the bark of Mangifera indica L. On the basis of chemical and spectral data, it has been formulated as 2-C-β-D-glucopyranosyl-3-meth
Abstract: A new xanthone C-glycoside, named homomangiferin, C19H17O10 (OCH3)·1.5H2O, decomposing over 250° without melting, [α]14D+8.7° (pyridine), was isolated from crude mangiferin obtained from the bark of Mangifera indica L. On the basis of chemical and spectral data, it has been formulated as 2-C-β-D-glucopyranosyl-3-methoxy-1, 6, 7-trihydroxyxanthone (II), i.e., 3-O-methylmangiferin. Of four possible monomethyl ethers in the aglycone moiety of mangiferin (I), the three, 1-, 3- and 7-methyl ethers, have been synthesized and the identity of homomangiferin with synthetic 3-O-methylmangiferin was confirmed by direct comparison. The nuclear magnetic resonance spectra of natural and synthetic II and of the heptaacetate (III) measured in pyridine solution showed the signals of methoxyl and acetoxyl groups as a doublet at room temperature (20-23°) and as a sharp singlet at 50°, whereas the methoxyl signals of 1-O- and 7-O-methylmangiferins (VII, XI) and of swertisin (6-C-β-D-glucopyranosyl-7-methoxy-4', 5-dihydroxyflavone) (XIV) appeared as a sharp singlet.
15 citations