- Synthesis of Flavonols via Pyrrolidine Catalysis: Origins of the Selectivity for Flavonol versus Aurone
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A novel synthetic method for flavonol from 2′-hydroxyl acetophenone and benzaldehyde promoted by pyrrolidine under an aerobic condition in water is established. This protocol was supported by efficient synthesis of 44 common examples and three natural products. The α, β-unsaturated iminium ion (enimine ion E) was proved to be the key intermediate in the reaction. H218O and 18O2 isotope tracking experiments demonstrated that both water and the aerobic atmosphere were necessary to ensure the transformation. The selectivity for flavonol or aurone was originated from solvent-triggered intermediates, which were determined by UV-visible spectra from isolated enimine. The phenol-iminium E-A is dominant in water and the ketoenamine intermediate E-B is prevalent in acetonitrile. In the presence of pyrrolidine and oxygen, E-A leads to flavonol through E-I, a zwitterionic-like phenoloxyl-iminium ion, following the key steps of cyclization and a [2 + 2] oxidation; E-B proceeds through path II, a radical process induced by photolysis of E-B with both pyrrolidine and oxygen, to afford aurone. Preliminary mechanistic studies are reported.
- Xiong, Wei,Wang, Xiaohong,Shen, Xianyan,Hu, Cuifang,Wang, Xin,Wang, Fei,Zhang, Guolin,Wang, Chun
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supporting information
p. 13160 - 13176
(2020/11/23)
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- Synthesis of 5-subsituted flavonols via the Algar-Flynn-Oyamada (AFO) reaction: The mechanistic implication
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Herein, we report a synthetic method with improved selectivity for 5-substituted flavonols via the Algar-Flynn-Oyamada reaction (AFO), by using of sodium carbonate/hydrogen peroxide A series of 5-substituted flavonols was obtained with moderate to high yields. The mechanism of the AFO reaction was elucidated. LCMS analysis and in situ 1H NMR analysis indicated that the epoxide was involved in the transformation from chalcone to flavonol and/or aurone under alkaline base/peroxide conditions.
- Shen, Xianyan,Zhou, Qiang,Xiong, Wei,Pu, Wenchen,Zhang, Wei,Zhang, Guolin,Wang, Chun
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p. 4822 - 4829
(2017/07/17)
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- Synthesis, biological evaluation, and molecular simulation of chalcones and aurones as selective MAO-B inhibitors
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A series of chalcones and aurones were synthesized and evaluated in vitro as monoamine oxidase inhibitors (MAOi). Our results show that aurones, which had not been previously reported as MAOi, are MAO-B inhibitors. Thus, both families inhibited selectively the B isoform of MAO in the micromolar range, offering novel scaffolds for the design of new and potent MAO inhibitors. The main structural requirements for their activity were characterized with the aid of 3D-QSAR and docking studies.
- Morales-Camilo, Nicole,Salas, Cristian O.,Sanhueza, Claudia,Espinosa-Bustos, Christian,Sepúlveda-Boza, Silvia,Reyes-Parada, Miguel,Gonzalez-Nilo, Fernando,Caroli-Rezende, Marcos,Fierro, Angélica
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p. 685 - 695
(2015/05/27)
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- A novel chalcone derivative and composition for anticancer comprising the same
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The present invention relates to a novel chalcone derivative and an anticancer composition including the chalcone derivative. In the present invention, provided are an anticancer drug for treating ovarian cancer cells and another anticancer drug for treating ovarian cancer cells having resistance to cisplatin. For this, in the present invention, provided is a compound denoted by chemical formula 1 in which R^1 is H or OCH_3, R^2 is OCH_3 or H, R^3 is OCH_3, R^4 is H, R^5 is OCH_3, R^6 is H and R^7 is OCH_3.
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Paragraph 0052-0055; 0074-0075
(2020/05/06)
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- 1H and 13C NMR spectral assignments of 2′-hydroxychalcones
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Chalcones are of interest to medicinal chemists because their structures can be easily modified with various functional groups. The syntheses and biological activities of chalcones from natural sources are well known. In this study, 24 2′-hydroxychalcones bearing methoxy substituents were synthesized, among which five are new. The NMR data for all synthesized chalcones are described for the first time. The complete assignments of the 1H and 13C NMR data can be used for the identification of newly discovered and widely isolated, synthesized chalcones. Copyright
- Yong, Yeonjoong,Ahn, Seunghyun,Hwang, Doseok,Yoon, Hyuk,Jo, Geunhyeong,Kim, Young Hwa,Kim, Sang Ho,Koh, Dongsoo,Lim, Yoongho
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p. 364 - 370
(2013/07/28)
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- Synthesis and PPAR-γ ligand-binding activity of the new series of 2′-hydroxychalcone and thiazolidinedione derivatives
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Fifteen chalcones and three thiazolidinedione (TZD) chalcones were prepared to evaluate their peroxisome proliferator-activated receptor-γ (PPAR-γ) ligand-binding activities. Among the three TZDs, one compound possessed PPAR-γ transactivation potential, while the others showed antagonistic activity against PPAR-γ transactivation. Among the chalcones, compound 5 was the most potent, and structure-activity relationship studies indicated that a methoxyl group in position C-4 and hydroxyl group in position C-4′ or 5′ in chalcone plays a key role in determining the potency of PPAR-γ activation.
- Sang, Hoon Jung,Soo, Young Park,Kim-Pak, Youngmi,Hong, Kyu Lee,Kyong, Soo Park,Kuk, Hyun Shin,Ohuchi, Kazuo,Shin, Hyun-Kyung,Sam, Rok Keum,Soon, Sung Lim
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p. 368 - 371
(2007/10/03)
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- Synthesis and inhibitory activity against COX-2 catalyzed prostaglandin production of chrysin derivatives
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A series of chrysin derivatives were prepared and evaluated for their inhibitory activities of cyclooxygenase-2 catalyzed prostaglandin production. Chrysin derivatives were prepared from 2-hydroxyacetophenone, 2,4-dihydroxyacetophenone and 2,6-dihydroxyacetophenone in 2 to 4 steps, respectively. Methxoylated chrysin derivatives were converted to the corresponding hydroxylated chrysin derivatives by the reaction with BBr 3 in good yields. The inhibitory activity of the chrysin derivatives against prostaglandin production from lipopolysaccharide-treated RAW 264.7 cells was measured. We found that chrysin derivatives with 3′,4′- dichloro substituents (5e, 6e and 7e) exhibited good inhibitory activity of prostaglandin production.
- Dao, Tran Thanh,Chi, Yeon Sook,Kim, Jeongsoo,Kim, Hyun Pyo,Kim, Sanghee,Park, Haeil
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p. 1165 - 1167
(2007/10/03)
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- 4'-Hydroxy-3-methoxyflavones with potent antipicornavirus activity
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4'-Hydroxy-3-methoxyflavones are natural compounds with known antiviral activities against picornaviruses such as poliomyelitis and rhinoviruses. In order to establish a structure-activity relationship a series of analogues were synthesized, and their antiviral activities and cytotoxicities were compared with those of flavones from natural origin. The 4'-hydroxyl and 3-methoxyl groups, a substitution in the 5 position and a polysubstituted A ring appeared to be essential requirements for a high activity. The most interesting compound was 4',7-dihydroxy-3-methoxy-5,6-dimethylflavone possessing in vitro TI99 values of > 1000 and > 200 against poliovirus type 1 and rhinovirus type 15, respectively. This compound was also active against other rhinovirus serotypes (2, 9, 14, 29, 39, 41, 59, 63, 70, 85, and 89) tested, having MIC50 values ranging from 0.016 to 0.5 μg/mL. Finally in contrast to quercetin it showed to be not mutagenic in concentrations up to 2.5 mg in the Ames test.
- De Meyer,Haemers,Mishra,Pandey,Pieters,Vanden Berghe,Vlietinck
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p. 736 - 746
(2007/10/02)
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- HETEROCYCLES. XIX. REACTION OF 2'-HYDROXYCHALCONES WITH ALKALINE HYDROGEN PEROXIDE
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Reaction of 2'-hydroxychalcones, which contain the hydroxyl and/or the methoxyl group at the 4- and 6'-positions, with alkaline hydrogen peroxide has been examined.It is observed that these substituents intricately influence the formation of the products.
- Takahashi, Hiroshi,Kubota, Yumiko,Fang, Lin,Onda, Masayuki
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p. 1099 - 1107
(2007/10/02)
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- Synthesis of (+/-)-Fistacacidin
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Synthesis of fistacacidin and (+/-)-2,3-trans-5,4'-dimethoxyflavan-3-ol (XVII) are reported.Synthesis of XII, starting from monobenzyl ether of 2,6-dihydroxyacetophenone (I) involves the reacti
- Patil, A. D.,Deshpande, V. H.
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p. 109 - 113
(2007/10/02)
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