109360-95-4Relevant academic research and scientific papers
7-O-METHYL-(2R:3R)-DIHYDROQUERCETIN 5-O-β-D-GLUCOSIDE AND OTHER FLAVONOIDS FROM PODOCARPUS NIVALIS
Markham, Kenneth R.,Webby, Rosemary F.,Vilain, Christian
, p. 2049 - 2052 (1984)
In the course of a chemotaxonomic survey of New Zealand Podocarpus species, a number of new flavonoid glycosides have been isolated from P. nivalis.These are: luteolin 3'-O-β-D-xyloside, luteolin 7-O-β-D-glucoside-3'-O-β-D-xyloside, dihydroquercetin 7-O-β-D-glucoside, 7-O-methyl-(2R:3R)-dihydrokaempferol 5-O-β-D-glucopyranoside, 7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucopyranoside, 7-O-methylkaempferol 5-O-β-D-glucopyranoside and 7-O-methylquercetin 5-O-β-D-glucopyranoside.Diagnostically useful physical techniques for distinguishing substitution patterns in dihydroflavonols are discussed and summarized.Glucosylation of the 5-hydroxyl group in (+)-dihydroflavonols is shown to reverse the sign of rotation at 589 nm.Key Word Index- Podocarpus nivalis; Podocarpaceae; snow totara; gymnosperm; flavonoid glycosides; 7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucoside; 7-O-methylquercetin 5-O-β-D-glucoside; luteolin 3'-O-β-D-xyloside; luteolin 7-O-β-D-glucoside-3'-O-β-D-xyloside; FAB-MS; 13C NMR.
Structure-activity relationship for (+)-taxifolin isolated from silymarin as an inhibitor of amyloid β aggregation
Sato, Mizuho,Murakami, Kazuma,Uno, Mayumi,Ikubo, Haruko,Nakagawa, Yu,Katayama, Sumie,Akagi, Ken-Ichi,Irie, Kazuhiro
, p. 1100 - 1103 (2013/07/27)
Silymarin, the seed extract of Silybium marianum, has preventive effects against Alzheimer's disease-like pathogenesis in vivo. We isolated (+)-taxifolin (4) from silymarin as an inhibitor of aggregation of the 42- residue amyloid -protein. Structure-activity relationship studies revealed the 30,40-dihydroxyl groups to be critical to the anti-aggregative ability, whereas the 7-hydroxyl group and the stereochemistry at positions 2 and 3 were not important.
Methylation of Dihydroquercetin Acetates: Synthesis of 5-O-Methyldihydroquercetin
Kiehlmann, Eberhard,Slade, Peter W.
, p. 1562 - 1566 (2007/10/03)
The major products of methylation of dihydroquercetin (1, dhq) with diazomethane have been identified as 7-O-methyldhq (9), 7,3′ -di-O-methyldhq (10), 7,4′-di-O-methyldhq (11), and 7,3′,4′ -tri-O-methyldhq (2). With dhq 3,7,3′,4′-tetraacetate (6), dhq 3,5,3′,4′-tetraacetate (5), dhq 3,3′,4′-triacetate (7), dhq 7,3′,4′-triacetate (8), and dhq 3-acetate (4) the same reaction affords mainly 5-O-methyldhq 3,7,3′,4′-tetraacetate (15), 7-O-methyldhq 3,5,3′,4′-tetraacetate (13), 7-O-methyldhq 3,3′,4′-triacetate (14), 5-O-methyldhq 7,3′,4′ -triacetate (25), and 7-O-methyldhq 3-acetate (12), respectively. The methylation of 8 is accompanied by intermolecular acetyl migration from phenolic oxygen to the hydroxy group of the heterocyclic ring. 5-O-Methyldhq (28) is accessible by deacetylation of 25. 5,7-Di-O-methyldhq (29), four known methyl ethers, 13 new and three known methyl ether acetates of dhq, and six new isomers with 2,3-cis stereochemistry were spectroscopically identified.
