- Synthesis of various kinds of isoflavones, isoflavanes, and biphenyl- ketones and their 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activities
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Forty-eight kinds of isoflavones (8), thirty-one isoflavanes (9), and forty-seven biphenyl-ketones (10, 10') were synthesized from eleven kinds of substituted phenols (11) and six phenylacetic acids (12). Among them, seventy-five compounds are new. The radical scavenging activities of these compounds were evaluated using 1,1- diphenyl-2-picrylhydrazyl (DPPH) at pH 6.0. We found that thirty-nine out of forty-three compounds having a catechol moiety on either the A- or the B-ring exhibited a high activity (ED50=12-54 μM) similar to that of catechin. In these cases, the remaining part of their structure seemed to have little effect on their activity. Many 6- or 8-hydroxyisoflavanes (9E-I) and their biphenyl-ketone derivatives (10E-H) also showed a high activity (ED50=50=26-32 μM). This study suggests that natural isoflavones have the possibilities of exhibiting antioxidant activities through the hydroxylation at the C6-, C8-, or C3'-position or the formation of the isoflavanes (9) and/or the biphenyl-ketone derivatives (10') by metabolism or biotransformation.
- Goto, Hideyuki,Terao, Yoshiyasu,Akai, Shuji
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experimental part
p. 346 - 360
(2009/12/27)
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- Microwave-promoted synthesis of polyhydroxydeoxybenzoins in ionic liquids
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A microwave-promoted synthesis of polyhydroxydeoxybenzoins and -phenylpropanones has been developed, using bis{(trifluoromethyl)sulfonyl}amine (HNTf2) or BF3·OEt2 in an ionic liquid solvent.
- Hakala, Ullastiina,W?h?l?, Kristiina
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p. 8375 - 8378
(2007/10/03)
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- Expedient Synthesis of Polyhydroxyisoflavones
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A general and direct synthesis of polyhydroxy isoflavones (3-phenyl-4H-1-benzopyran-4-ones) starting from the corresponding unprotected phenols and arylacetic acids is described.The aryl rings may carry additional alkyl, methoxy and/or halogeno groups.Intermediate polyhydroxydeoxybenzoins (1,2-diphenylethanones) can also be isolated in good yields.
- Waehaelae, Kristiina,Hase, Tapio A.
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p. 3005 - 3008
(2007/10/02)
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