- Catalytic Alkyne Arylation Using Traceless Directing Groups
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By using Pd0/Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C?C bond formation.
- Park, Jung-Woo,Kang, Bubwoong,Dong, Vy M.
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supporting information
p. 13598 - 13602
(2018/09/25)
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- A versatile synthesis of O-desmethylangolensin analogues from methoxy-substituted benzoic acids
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The synthesis of O-desmethylangolensin (O-DMA) analogues from methoxy-substituted benzoic acids was described. Treatment of methoxy-substituted benzoic acids with 2 equiv of ethyllithium afforded methoxypropiophenones, which were subsequently transformed to ethyl 2-(methoxyphenyl)propionates via 1,2-rearrangement of the methoxyphenyl group using Pb(OAc)4/HClO4 in triethyl orthoformate. After hydrolysis with KOH, the 2-(methoxyphenyl)propionic acids were reacted with di- 2-pyridyl carbonate to afford 2-pyridyl 2-(methoxyphenyl)propionates, which were acylated with methoxy-substituted phenylmagnesium bromides to give methoxy-α-methyldesoxybenzoins. The methoxy groups of these compounds were selectively or fully demethylated using boron tribromide to give diverse O-DMA analogues in high yields.
- Hong, Hyo Jeong,Lee, Jae In
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p. 569 - 574
(2015/02/05)
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- 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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- Synthesis of α-methyldeoxybenzoins
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Reduction of hydroxy and/or methoxy-substituted isoflavones using LiAlH4 in refluxing THF provides an easy access to a number of α-methyldeoxybenzoins, possible metabolites of phytoestrogens in man. The synthesis of O-demethylangolensin 2b, 6′-hydroxyangolensin 2c, angolensin 2d, 1-(2,4-dihydroxyphenyl)-2-phenylpropan-1-one 2e, 1-(2-hydroxy-4-methoxyphenyl)-2-(4-hydroxyphenyl)propan-1-one2f, 4′-O-methylangolensin 2g, 1-(2-hydroxy-4-methoxyphenyl)-2-phenylpropan-1-one 2h, and 1-(2-hydroxyphenyl)-2-phenylpropan-1-one 2i is described. The Royal Society of Chemistry 1999.
- Salakka,Waehaelae
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p. 2601 - 2604
(2007/10/03)
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