- Microanalysis of a selective potent anti-Helicobacter pylori compound in a Brazilian medicinal plant, Myroxylon peruiferum and the activity of analogues
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A selective potent anti-Helicobacter pylori isoflavone was isolated from a Brazilian Medicinal Plant, Myroxylon peruiferum. The isolation bioassay- guided and the characterization of an active anti-H, pylori constituent was performed using the methanol extract of plant of minute amount. The active compound was identified as cabreuvin (1), an isoflavone derivative. The structure-activity relationships of several related compounds were also investigated.
- Ohsaki, Ayumi,Takashima, Junko,Chiba, Noriko,Kawamura, Makoto
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- Enantioselective Synthesis of Isoflavanones and Pterocarpans through a RuII-Catalyzed ATH-DKR of Isoflavones
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Noyori-Ikariya RuII complexes promoted the one-pot C=C/C=O bonds reduction of isoflavones using sodium formate as the hydrogen source through Asymmetric Transfer Hydrogenation-Dynamic Kinetic Resolution (ATH-DKR). Due to the neutral conditions employed, isoflavones with different substituents at the 2’-position of B-ring (H, OH, OMe and Br) were successfully reduced. Ten cis-3-phenylchroman-4-ols were selectively obtained (>20 : 1 dr) in good yields (up to 86 %) and excellent enantioselectivities (up to >99 : 1 er). The synthetic applications of these chiral compounds were also demonstrated. Enantioenriched isoflavanones were obtained under mild metal-free oxidation of the cis-3-phenylchroman-4-ols while pterocarpans were synthesized by two strategies: an acid-catalyzed cyclization and a novel approach based on a Pd-catalyzed C?O intramolecular cross-coupling reaction.
- Caleffi, Guilherme S.,Costa, Paulo R. R.,Costa-Júnior, Paulo C. T.,Gaspar, Francisco V.
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p. 5097 - 5108
(2021/10/20)
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- Natural Isoflavones and Semisynthetic Derivatives as Pancreatic Lipase Inhibitors
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Obesity, now widespread all over the world, is frequently associated with some chronic diseases. Thus, there is a growing interest in the prevention and treatment of obesity. To date, the only antiobesity drug is orlistat, a natural product-derived pancreatic lipase (PL) inhibitor with some undesired side effects. In the last decades, many natural compounds or derivatives have been evaluated as potential PL inhibitors, and natural polyphenols are among the most promising for possible exploitation as antiobesity agents. However, few studies have been devoted to isoflavones. In this work, we report a study on the PL inhibitory properties of a small library of semisynthetic isoflavone derivatives together with the natural leads daidzein (1), genistein (2), and formononetin (3). In vitro lipase inhibition assay showed that 2 is the most promising PL inhibitor. Among synthetic isoflavones, the hydroxylated and brominated derivatives were more potent than their natural leads. Detailed studies through fluorescence measurements and kinetics of lipase inhibition showed that 2 and the bromoderivatives 10 and 11 have the greatest affinity for PL. Docking studies corroborated these findings highlighting the interactions between isoflavones and the enzyme, confirming that hydroxylation and bromination are useful modifications.
- Cardullo, Nunzio,Muccilli, Vera,Pulvirenti, Luana,Tringali, Corrado
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p. 654 - 665
(2021/04/02)
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- Stille coupling for the synthesis of isoflavones by a reusable palladium catalyst in water
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Isoflavones were synthesized from the reaction of 3-bromochromone derivatives and aryltributylstannanes via Stille coupling catalyzed by a water-soluble and reusable PdCl2(NH3)2/2,2′-cationic bipyridyl system in aqueous solution. For prototype 3-bromochromone, the coupling reaction was performed at 80°C for 24 hr with 2.5 mol% catalyst in water in the presence of tetrabutylammonium fluoride. After the reaction, the aqueous solution could be reused for several runs, indicating that its activity was only slightly decreased. For substituted 3-bromochromones, the addition of NaHCO3 and a higher reaction temperature (120°C) were required to gain satisfactory outcomes. In addition, naturally occurring products, such as daidzein, could be obtained by this protocol via a one-pot reaction.
- Chang, Ya-Ting,Liu, Ling-Jun,Peng, Wen-Sheng,Lin, Lin-Ting,Chan, Yi-Tsu,Tsai, Fu-Yu
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p. 469 - 475
(2021/02/03)
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- Synthesis method of 3 ', 4', 7-trihydroxy isoflavone
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The invention discloses a synthesis method of 3', 4', 7-trihydroxy isoflavone. The method comprises the steps that 4', 7-dimethoxyisoflavone and bromine are subjected to a mixed reaction in a dichloromethane medium to obtain 3'-bromo-4 ', 7-dimethoxyisoflavone, wherein the molar ratio of 4', 7-dimethoxyisoflavone to bromine is 1: 1.1-1.5, and the reaction temperature is 20-30 DEG C; the 3'-bromo-4', 7-dimethoxyisoflavone reacts with sodium methoxide under the action of cuprous salt to obtain 3', 4', 7-trimethoxyisoflavone; and the 3', 4', 7-trimethoxyisoflavone is demethylated to obtain the 3', 4', 7-trihydroxy isoflavone. Compared with the prior art, the method has the advantages of abundant sources of initial raw materials, mild reaction conditions, high selectivity and high yield, and is suitable for industrial production.
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- Synthesis of isoflavones containing naturally occurring substitution pattern by oxidative rearrangement of respective flavanones using thallium(III) p-tosylate
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Claisen condensation of substituted 2′-hydroxyacetophenones 1a-c with aromatic aldehydes affords respective substituted 2′-hydroxychalcones 2a-n which on base catalyzed cyclization in pyridine:methanol:water (1:1:1) give respective flavanones 3a-n. The oxidative rearrangement of flavanones with thallium(III) p-tosylate furnishes respective isoflavones 4a-n in overall 62-72% yields starting from 1. The present methodology has been successfully applied for the synthesis of naturally occurring isoflavones such as di-O-methyldaidzein 4a, cabruvin 4b, pseudobabtigenin methylether 4d, 5,7-dimethoxyisoflavone 4f, 5,7,4′-trimethoxyisoflavone 4g, derrustone 4i, 7,8,3′,4′- tetramethoxyisoflavone 41, purpuranin-A 4m and 7,8,3′,4′,5′- pentamethoxyisoflavone 4n and thus the first synthesis of 4n is reported.
- Singh, Om V.,Muthukrishnan,Sunderavadivelu
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p. 2575 - 2581
(2007/10/03)
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- HYDROBORATIONS: NEW SYNTHESIS OF PSEUDO-BAPTIGENIN, O-METHYL PSEUDO-BAPTIGENIN AND CABREUVIN.
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Application of hydroboration followed by chromic acid oxydation to 4-hydroxy 7-methoxy(3',4'-methylenedioxyphenyl) coumarin and 4-hydroxy 7-benzyloxy 3-(3',4'-methylenedioxyphenyl) coumarin forms the corresponding isoflavanones which are dehydrogenated into isoflavones.
- Kirkiacharian, B. Serge,Brion, Jean-Daniel,Gomis, Michel,Reynaud, Pierre
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p. 1929 - 1934
(2007/10/02)
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- Flavonoid synthesis based on photolysis of flavan-3-ols, 3-hydroxyflavanones, and 2-benzylbenzofuranones
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Irradiation of flavan-3-ols, 3-hydroxyflavanones, and 2-benzylbenzofuranones in methanol leads mainly to photochemical opening of the heterocyclic ring, or to its complete photofragmentation, the products being trapped by reaction with the solvent. Fission of exocyclic C-O bonds also occurs, accompanied by intramolecular rearrangements. The course of these reactions is often dependent on the position and nature of substituents. The conversions provide novel routes to 1,3-diaryl-1-methoxypropan-2-ols, 1,3-diaryl-2,2-dimethoxypropan-1-ones, cis-3-methoxyflavanones, isoflavones, flavanones, and trans-chalcones, and hence to α-hydroxychalcones, cis- and trans-α-methoxychalcones, and 2-methoxy-2-(α-methoxybenzyl)benzofuranones.
- Fourie, Theunis G.,Ferreira, Daneel,Roux, David G.
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p. 125 - 133
(2007/10/07)
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