98755-25-0Relevant academic research and scientific papers
SYNTHESIS OF 5,8-DIHYDROXY-6,7-DIMETHOXYFLAVONES AND REVISED STRUCTURES FOR SOME NATURAL FLAVONES
Horie, Tokunaru,Kawamura, Yasuhiko,Yamamoto, Hitoshi,Kitou, Takeshi,Yamashita, Kazuyo
, p. 1201 - 1210 (2007/10/02)
Six 5,8-dihydroxy-6,7-dimethoxyflavones and three 8-hydroxy-5,6,7-trimethoxyflavones were synthesized from 2',5'-dihydroxy-3',4',6'-trimethoxyacetophenone by adapting the selective O-alkylation and dealkylation, and the differentiation between the flavones and their isomeric 6-hydroxyflavones was clarified by 1H NMR and UV spectra.Four natural flavones proposed as 5,8-dihydroxy-6,7-dimethoxyflavones, must have other structures and three are shown to be isomeric 5,7-dihydroxy-6,8-dimethoxyflavones.A flavone, isolated from Helichrysum, is revised to the isomeric 7-hydroxy-5,6,7-trimethoxyflavone,
TLC, UV AND ACIDIC TREATMENT IN THE DIFFERENTIATION OF 5,6- AND 5,8-DIHYDROXYFLAVONES, 3-METHOXYFLAVONES AND FLAVONOLS
Barberan, F.A.T.,Ferreres, F.,Tomas, F.
, p. 5733 - 5740 (2007/10/02)
UV and TLC techniques constitute easy procedures to distinguish between 5,6-dihydroxy-7,8-dimethoxy- and 5,8-dihydroxy-6,7-dimethoxyflavonoids, that are difficult to characterize by NMR and classical UV techniques.The acidic treatment of the original products to obtain Wessely-Moser isomers, useful for comparison purposes, yielded novel demethylated products.UV and MS data of 5,8,4' -trihydroxy-6,7,3'-trimethoxyflavone, 5,6,8,3',4'-pentahydroxy-7-methoxyflavone and 5,6,8,4'-tetrahydroxy-7,3'-dimethoxyflavone are presented for the first time.
5,6,4'-TRIHYDROXY-7,8-DIMETHOXYFLAVONE FROM THYMUS MEMBRANACEUS
Ferreres, Federico,Barberan, Francisco A. T.,Thomas, Francisco
, p. 1869 - 1871 (2007/10/02)
From the extracts of Thymus membranaceus subsp. membranaceus, the new naturally occuring 5,6,4'-trihydroxy-7,8-dimethoxyflavone (thymusin) has been isolated and identified.Its structure was elucidated by comparison with its isomeric flavone obtained on ac
