- A practical synthesis of the flavone, scutellarein
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A practical and economical five-step synthesis of the flavone scutellarein has been achieved in 60% overall yield using the available and cheap 2,6-dimethoxy-1,4-benzoquinone as starting material. The reaction sequence involved reduction to the corresponding quinol, Friedel-Crafts acetylation, Claisen-Schmidt condensation with p-methoxybenzaldehyde, cyclisation and demethylation. The procedure is operationally simple and amenable to scale-up synthesis.
- Wang, Qian,Liao, Xia-Li,Xiang, Cheng,Yang, Jian
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p. 157 - 159
(2017/03/27)
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- Method for preparing scutellarin
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The invention relates to a method for preparing scutellarin. According to the method, the scutellarin can be efficiently prepared from 2,6-dimethoxy benzoquinone as a starting raw material through five reactions of reduction, Friedel-Crafts acetylation, Claisen condensation, dehydrogenation oxidation cyclization and demethylation. The starting raw material and a reagent are cheap and easily available, synthetic steps are few, the operation is simple and convenient, the production control is simple, the product yield is high, and the purity is high. The method is applicable to large-scale preparation and production application of the scutellarin.
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Paragraph 0013
(2017/01/02)
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- A practical and economical high-yielding, six-step sequence synthesis of a flavone: Application to the multigram-scale synthesis of ladanein
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Herein we report a short and economic synthesis of the antiviral flavonoid lead ladanein (1). Ladanein is obtained from 2,6-dimethoxyquinone (11) in six steps with 51% overall yield. After a high-yielding reductive acetylation and Fries rearrangement, the
- Martin-Benlloch, Xavier,Elhabiri, Mourad,Lanfranchi, Don Antoine,Davioud-Charvet, Elisabeth
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p. 613 - 617
(2014/06/09)
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- Flavone derivatives and their use
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The present invention relates to flavone derivatives and to compositions containing one or more of these flavone derivatives. The present invention further relates to flavone derivatives or compositions for use in the treatment and/or prevention of a vira
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- FLAVONE DERIVATIVES AND THEIR USE
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The present invention relates to flavone derivatives and to compositions containing one or more of these flavone derivatives. The present invention further relates to fiavone derivatives or compositions for use in the treatment and/or prevention of a vira
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- Studies of the selective O-alkylation and dealkylation of flavonoids. XVIII. A convenient method for synthesizing 3,5,6,7-tetrahydroxyflavones
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In the demethylation of 6-hydroxy-3,4',7-trimethoxy-5-(tosyloxy)flavone with anhydrous aluminum bromide, the 5-tosyloxyl group was eliminated with bromination to give 8-bromo-3,6,7-trihydroxy-4'-methoxyflavone as the main product. When anhydrous aluminum chloride was used in the demethylation of the acetate, the 5-tosyloxyl group was cleaved prior to the demethylation to give 5,6,7-trihydroxy-3,4'-dimethoxyflavone. Demethylation of 6-hydroxy-4',5,7-trimethoxy-3-(tosyloxy)flavone and its acetate with the bromide or chloride afforded the 5,6,7-trihydroxyflavone without the cleavage of the 3-tosyloxyl group, but was not suitable for the general synthesis of the 3,5,6,7-tetrahydroxyflavones because of the difficulty in removing the protecting group. Consequently, it was found that the direct demethylation of 3,6-dihydroxy-5,7-dimethoxyflavones with anhydrous aluminum chloride-sodium iodide in acetonitrile was the most useful general method for synthesizing 3,5,6,7-tetrahydroxyflavones. Additionally, the reported structures of two natural flavones were revised.
- Horie,Kobayashi,Kawamura,Yoshida,Tominaga,Yamashita
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p. 2033 - 2041
(2007/10/03)
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