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Showing papers on "Xanthone published in 1969"


Journal ArticleDOI
TL;DR: A new xanthone C-glucoside, C19H18O11·1/2H2O, decomposing over 260° without melting, [α]21D+5.5° (pyridine), was isolated in a pure state along with mangiferin (I) from the aerial parts of Anemarrhena asphodeloides BUNGE (Liliaceae) and named isomangiferin this article.

37 citations



Journal ArticleDOI
TL;DR: The co-occurrence of isomeric xanthones in certain plant extracts suggests their derivation from a common hydroxylated benzophenone as discussed by the authors, and in vitro oxidation of some of these benzophenones produces xanthone mixtures corresponding to oxidative coupling occurring para and ortho or para only to an activating hydroxy group.
Abstract: The co-occurrence of isomeric xanthones in certain plant extracts suggests their derivation from a common hydroxylated benzophenone. In vitro oxidation of some of these benzophenones produces xanthone mixtures corresponding to oxidative coupling occurring para and ortho or para only to an activating hydroxy-group. The oxidations can also be carried out enzymically.

13 citations


Journal ArticleDOI
TL;DR: In this paper, 2-C and 4-C-methylxanthones with different oxygenation patterns have been synthesized by two methods: (1) nuclear methylation of 1,3-dihydroxy xanthones (I) to the corresponding 2-c-methyl derivatives (II) and (2) condensation of 2-methyl-(VI) and 4methyl-(IX) 3,5-dimethoxyphenols with substituted salicylic acids.

7 citations


Journal ArticleDOI
TL;DR: Polygalaxanthone A has been shown by synthesis to have the structure 1,2,3-trimethoxy-6,7-methylenedioxyxanthone (2a ) and not that originally proposed as discussed by the authors.

3 citations


Journal ArticleDOI
01 Mar 1969
TL;DR: In this article, the synthesis of 3, 5′-dimethyl- and 3, 4′ -dimethylfuraro (2′, 3′:1, 2)−6, 7-benzoxanthones (III and IV) is described.
Abstract: The Synthesis of 3, 5′-dimethyl- and 3,4′-dimethyl-furaro (2′, 3′:1, 2)−6, 7-benzoxanthones (III and IV) is described.

3 citations