- Size and branching effects on the fluorescence of benzylic dendrimers possessing one apigenin fluorophore at the core
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Different generations of dendrimers incorporating one fluorescent core of apigenin and three Fréchet benzylic dendrons have been prepared. The chief geometric features of these dendrimers have been obtained by Molecular Dynamics simulations. These computa
- Vin?, Petr,Vermachová, Martina,Dra?ar, Pavel,Del Barrio, Melisa,Jarne, Carmen,Cebolla, Vicente L.,De Cózar, Abel,Zangi, Ronen,Cossío, Fernando P.
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Read Online
- Flavonoid-based inhibitors of the Phi-class glutathione transferase from black-grass to combat multiple herbicide resistance
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The evolution and growth of multiple-herbicide resistance (MHR) in grass weeds continues to threaten global cereal production. While various processes can contribute to resistance, earlier work has identified the phi class glutathione-S-transferase (AmGSTF1) as a functional biomarker of MHR in black-grass (Alopecurus myosuroides). This study provides further insights into the role of AmGSTF1 in MHR using a combination of chemical and structural biology. Crystal structures of wild-type AmGSTF1, together with two specifically designed variants that allowed the co-crystal structure determination with glutathione and a glutathione adduct of the AmGSTF1 inhibitor 4-chloro-7-nitro-benzofurazan (NBD-Cl) were obtained. These studies demonstrated that the inhibitory activity of NBD-Cl was associated with the occlusion of the active site and the impediment of substrate binding. A search for other selective inhibitors of AmGSTF1, using ligand-fishing experiments, identified a number of flavonoids as potential ligands. Subsequent experiments using black-grass extracts discovered a specific flavonoid as a natural ligand of the recombinant enzyme. A series of related synthetic flavonoids was prepared and their binding to AmGSTF1 was investigated showing a high affinity for derivatives bearing a O-5-decyl-α-carboxylate. Molecular modelling based on high-resolution crystal structures allowed a binding pose to be defined which explained flavonoid binding specificity. Crucially, high binding affinity was linked to a reversal of the herbicide resistance phenotype in MHR black-grass. Collectively, these results present a nature-inspired new lead for the development of herbicide synergists to counteract MHR in weeds. This journal is
- Brazier-Hicks, Melissa,Coxon, Christopher R.,Cummins, Ian,Edwards, Robert,Eno, Rebecca F. M.,Freitag-Pohl, Stefanie,Hughes, David J.,Mitchell, Glynn,Moore, Jenny,Onkokesung, Nawaporn,Pohl, Ehmke,Schwarz, Maria,Steel, Patrick G.,Straker, Hannah E.,Wortley, David J.
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p. 9211 - 9222
(2021/11/16)
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- Discovery of Novel Apigenin-Piperazine Hybrids as Potent and Selective Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors for the Treatment of Cancer
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Poly (ADP-ribose) polymerase-1 (PARP-1) is a potential target for the discovery of chemosensitizers and anticancer drugs. Amentoflavone (AMF) is reported to be a selective PARP-1 inhibitor. Here, structural modifications and trimming of AMF have led to a series of AMF derivatives (9a-h) and apigenin-piperazine/piperidine hybrids (14a-p, 15a-p, 17a-h, and 19a-f), respectively. Among these compounds, 15l exhibited a potent PARP-1 inhibitory effect (IC50 = 14.7 nM) and possessed high selectivity to PARP-1 over PARP-2 (61.2-fold). Molecular dynamics simulation and the cellular thermal shift assay revealed that 15l directly bound to the PARP-1 structure. In in vitro and in vivo studies, 15l showed a potent chemotherapy sensitizing effect against A549 cells and a selective cytotoxic effect toward SK-OV-3 cells through PARP-1 inhibition. 15l·2HCl also displayed good ADME characteristics, pharmacokinetic parameters, and a desirable safety margin. These findings demonstrated that 15l·2HCl may serve as a lead compound for chemosensitizers and the (BRCA-1)-deficient cancer therapy.
- Long, Huan,Hu, Xiaolong,Wang, Baolin,Wang, Quan,Wang, Rong,Liu, Shumeng,Xiong, Fei,Jiang, Zhenzhou,Zhang, Xiao-Qi,Ye, Wen-Cai,Wang, Hao
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p. 12089 - 12108
(2021/09/06)
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- Divergent synthesis of flavones and flavanones from 2′-hydroxydihydrochalconesviapalladium(ii)-catalyzed oxidative cyclization
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Divergent and versatile synthetic routes to flavones and flavanonesviaefficient Pd(ii) catalysis are disclosed. These Pd(ii) catalyses expediently provide a variety of flavones and flavanones from 2′-hydroxydihydrochalcones as common intermediates, depending on oxidants and additives,viadiscriminate oxidative cyclization sequences involving dehydrogenation, respectively, in a highly atom-economic manner.
- Son, Seung Hwan,Cho, Yang Yil,Yoo, Hyung-Seok,Lee, Soo Jin,Kim, Young Min,Jang, Hyu Jeong,Kim, Dong Hwan,Shin, Jeong-Won,Kim, Nam-Jung
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p. 14000 - 14006
(2021/04/22)
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- Novel chromenone derivatives having substituted biphenyl group and a pharmaceutical composition for prevention or treatment of allergic diseases compring the same
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The present invention relates to: a novel chromenone derivative compound capable of effectively suppressing an allergic immune response by inhibiting signal transduction mediated by thymic stromal lymphopoietin (TSLP); and a pharmaceutical composition capable of fundamentally preventing or treating various allergic diseases by using the same.COPYRIGHT KIPO 2021
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Paragraph 0103-0110; 0112-0116
(2020/11/26)
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- Synthesis method of isolicoflavonol
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The invention provides a synthesis method of isolicoflavonol, which comprises the following steps: carrying out condensation reaction on 2,4-O-R1(protective group, the same below)-6-hydroxyacetophenone and 4-O-R2(protective group, the same below)-benzaldehyde to generate 2',4'-O-R1-6'-hydroxy-4-O-R2-chalcone; oxidizing the chalcone to generate flavonol; carrying out selective protection on 3-OH ofthe flavonol to obtain 3,5,7-O-R1-4'-O-R2-flavonol; removing the protecting group R2 from the 3,5,7-O-R1-4'-O-R2-flavonol to obtain 3,5,7-O-R1-4'-hydroxyflavonol; carrying out 1,1-dimethylpropargyl reaction on the 4,4'-OH site to obtain 3,5,7-O-R1-4'-O-(1',1''-dimethyl propargyl)flavonol; carrying out partial hydrogenation on the alkynyl of the 3,5,7-O-R1-4'-O-(1',1''-dimethyl propargyl)flavonolunder the action of a catalyst to obtain 3,5,7-O-R1-4'-O-(1',1''-dimethylpropenyl)flavonol and carrying out Claisen rearrangement on the 3,5,7-O-R1-4'-O-(1',1''-dimethylpropenyl)flavonol to obtain 3,5,7-O-R1-isolicoflavonol, and removing the protecting group R1 from the 3,5,7-O-R1-isolicoflavonol to obtain the isolicoflavonol.
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Paragraph 0111; 0239-0245
(2020/12/29)
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- Correlation study on methoxylation pattern of flavonoids and their heme-targeted antiplasmodial activity
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A library of 33 polymethoxylated flavones (PMF) was evaluated for heme-binding affinity by biomimetic MS assay and in vitro antiplasmodial activity on two strains of P. falciparum. Stability of heme adducts was discussed using the dissociation voltage at 50% (DV50). No correlation was observed between the methoxylation pattern and the antiparasitic activity, either for the 3D7 chloroquine-sensitive or for the W2 chloroquine-resistant P. falciparum strains. However, in each PMF family an increased DV50 was observed for the derivatives methoxylated in position 5. Measurement of intra-erythrocytic hemozoin formation of selected derivatives was performed and hemozoin concentration was inversely correlated with heme-binding affinity. Kaempferol showed no influence on hemozoin formation, reinforcing the hypothesis that this compound may exert in vitro antiplasmodial activity mostly through other pathways. Pentamethoxyquercetin has simultaneously demonstrated a significant biological activity and a strong interaction with heme, suggesting that inhibition of hemozoin formation is totally or partially responsible for its antiparasitic effect.
- Boutefnouchet, Sabrina,Bouzidi, Chouaha,Cojean, Sandrine,Figadère, Bruno,Grougnet, Rapha?l,Maciuk, Alexandre,Michel, Sylvie,Ortiz, Sergio,Vásquez-Ocmín, Pedro G.
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- Scope and Mechanism of the Ruthenium-Catalyzed Dehydrative C-H Coupling of Phenols with α,β-Unsaturated Carbonyl Compounds: Expedient Synthesis of Chromene and Benzoxacyclic Derivatives
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Chromene and benzoxacyclic derivatives were efficiently synthesized from the ruthenium-catalyzed dehydrative C-H coupling reaction of phenols with α,β-unsaturated carbonyl compounds. The cationic ruthenium-hydride complex was found to be an effective catalyst for the coupling and annulation of phenols with enals to form chromene products. The coupling of phenols with linear enones afforded 2,4-disubstituted chromene derivatives, whereas the analogous coupling with cyclic enones yielded 9-hydroxybenzoxazole products. The reaction of 3,5-dimethoxyphenol with PhCH=CHCDO resulted in the chromene product with a significant H/D exchange to both benzylic and vinyl positions. The most significant carbon isotope effect from the coupling of 3,5-dimethoxyphenol with 4-methoxycinnamaldehyde was observed on the α-olefinic carbon of the chromene product (C(2) = 1.067). A Hammett plot from the coupling of 3,5-dimethoxyphenol with para-substituted p-X-C6H4CH=CHCHO displayed a linear correlation, with a strong promotional effect by an electron-withdrawing group (ρ = +1.5; X = OCH3, CH3, H, F, Cl). Several biologically active chromenone derivatives were synthesized by using the catalytic coupling method. The catalytic method provides an expedient synthetic protocol for the coupling of phenols with α,β-unsaturated carbonyl compounds without employing reactive reagents or forming any wasteful byproducts.
- Mokar, Bhanudas Dattatray,Yi, Chae S.
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p. 4625 - 4632
(2019/12/24)
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- Diversity-oriented synthesis of pyrazoles derivatives from flavones and isoflavones leads to the discovery of promising reversal agents of fluconazole resistance in Candida albicans
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Diversity-oriented synthesis of derivatives of natural products is an important approach for the discovery of novel drugs. In this paper, a series of novel 3,4-diaryl-1H-pyrazoles and 3,5-diaryl-1H-pyrazoles derivatives were synthesized through the one-po
- Cui, Chang-Yi,Liu, Jun,Zheng, Hong-Bo,Jin, Xue-Yang,Zhao, Xiao-Yu,Chang, Wen-Qiang,Sun, Bin,Lou, Hong-Xiang
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supporting information
p. 1545 - 1549
(2018/04/02)
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- Synthesis of Benzopyran-Fused Flavone Derivatives via Microwave-Assisted Intramolecular C-H Activation
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A microwave-assisted intramolecular direct arylation method for the synthesis of benzopyran-fused flavone derivatives containing natural flavone backbones is described. Different polyalkoxy flavones were synthesized and functionalized with 2-bromobenzyl bromide. The resulting compounds were subjected to palladium-catalyzed intramolecular direct arylation reactions supported by microwave irradiation to produce fused tetracyclic flavones. In the case of the 7-substituted chrysin derivative, the regioselectivity of the coupling was also examined.
- Sipos, Zoltán,Kónya, Krisztina
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supporting information
p. 1610 - 1620
(2018/03/21)
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- First Total Synthesis of Original Chalcone–Flavone Dimers as Cissampeloflavone Analogues
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The total synthesis of furoflavones closely related to the natural product cissampeloflavone was explored following different pathways. The involvement of a flavone as a key intermediate proved to be the most efficient way to form the 7-phenyl-5H-furo[3,2-g]chromen-5-one scaffold, and the first example of furoflavone formation was achieved in this way. For the synthesis of chalcone–flavone dimers, two different strategies were examined: either acylation at the very end of the synthesis, or introduction of the 3-acyl group during furan-ring formation. The final acylation was hardly achievable with hindered benzoyl chlorides, but a simpler 4-methoxybenzoyl group was added to the furoflavone in modest yield. The alternative direct introduction of this acyl group during furan formation proved to be more efficient. Conjugate addition of an iodoflavone to an ynone followed by intramolecular Heck cyclization gave the best results, leading to the first synthetic chalcone–flavone dimer ever described.
- Thévenin, Marion,Thoret, Sylviane,Dubois, Jo?lle
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p. 5843 - 5852
(2018/11/24)
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- Use of flavone and flavanone derivatives in preparation of sedative and hypnotic drugs
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Disclosed is a use of flavones derivatives and flavanone derivatives in preparation of sedative and hypnotic drugs.
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Page/Page column 38
(2017/07/01)
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- Total synthesis of agalloside, isolated from: Aquilaria agallocha, by the 5-O-glycosylation of flavan
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Agalloside (1) is a neural stem cell differentiation activator isolated from Aquilaria agallocha by our group using Hes1 immobilized beads. We conducted the first total synthesis of agalloside (1) via the 5-O-glycosylation of flavan 25 using glycosyl fluoride 20 in the presence of BF3·Et2O. Subsequent oxidation with DDQ to flavanone 2 and deprotection successively provided agalloside (1). This synthetic strategy holds promise for use in the synthesis of 5-O-glycosylated flavonoids. The synthesized agalloside (1) accelerated neural stem cell differentiation, which is a result comparable to that for the naturally occurring compound 1.
- Arai, Midori A.,Yamaguchi, Yumi,Ishibashi, Masami
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p. 5025 - 5032
(2017/07/10)
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- Identification and structure activity relationship of novel flavone derivatives that inhibit the production of nitric oxide and PGE2 in LPS-induced RAW 264.7 cells
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In an effort to identify novel anti-inflammatory compounds, a series of flavone derivatives were synthesized and biologically evaluated for their inhibitory effects on the production of nitric oxide (NO) and prostaglandin E2 (PGE2), representative pro-inflammatory mediators, in LPS-induced RAW 264.7 cells. Their structure-activity relationship was also investigated. In particular, we found that compound 3g displayed more potent inhibitory activities on PGE2 production, similar inhibitory activities on NO production and less weak cytotoxicity than luteolin, a natural flavone known as a potent anti-inflammatory agent.
- An, Ji-Young,Lee, Hwi-Ho,Shin, Ji-Sun,Yoo, Hyung-Seok,Park, Jong Seon,Son, Seung Hwan,Kim, Sang Won,Yu, Jihyun,Lee, Jun,Lee, Kyung-Tae,Kim, Nam-Jung
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p. 2613 - 2616
(2017/05/10)
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- An improved synthesis of apigenin and luteolin
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Apigenin and luteolin are the antioxidant flavonoids found in foods such as parsley, artichoke, basil and celery. Both of these compounds have shown the ability to protect cells against cancer and also to inhibit DNA oxidative damage. These flavonoids are part of many nutraceutical formulations available in the market. There is a need for the development of cost effective methodologies to produce them in large quantities. The synthetic process developed for both these compounds is general and can be applied for other flavonoids also. An industrially applicable high pure product, cost effective synthesis and general synthetic method has been developed and presented.
- Rambabu,Kumari,Baby Ramana,Ramani,Subbaraju,Hari Babu
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p. 1139 - 1143
(2016/03/01)
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- An improved synthesis of apigenin
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Two routes for the synthesis of the flavone apigenin are described. In the first, taxicatigenin was converted to 2-hydroxy-4,6- dimethoxyacetophenone and then by condensation with anisaldehyde to 2′-hydroxy-4,4′,6′-trimethoxychalcone. The latter was cyclised with iodine and demethylated with pyridine hydrochloride to form apigenin in 53% overall yield. In the second route, a single step for the preparation of the chalcone was used in which 1,3,5-trimethoxybenzene was acylated with p-methoxycinnamic acid. Although the synthesis of apigenin was achieved in a lower overall yield of 34%, the process was simpler.
- Wang, Qian,Cui, Wei,Liu, Man,Zhang, Ji,Liao, Rong-Qiang,Liao, Xia-Li,Yang, Jian
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- A versatile approach to flavones via a one-pot Pd(II)-catalyzed dehydrogenation/oxidative boron-Heck coupling sequence of chromanones
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A variety of flavones were expediently synthesized from readily accessible chromanones via a one-pot sequence involving Pd(ii)-catalyzed dehydrogenation and oxidative boron-Heck coupling with arylboronic acid pinacol esters. In particular, the use of arylboronic acid pinacol esters was found to significantly improve the yield of the reaction.
- Lee, Jun,Yu, Jihyun,Son, Seung Hwan,Heo, Jinyuk,Kim, Taelim,An, Ji-Young,Inn, Kyung-Soo,Kim, Nam-Jung
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p. 777 - 784
(2016/01/12)
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- Metal-free methodology for the preparation of sterically hindered alkynoylphenols and its application to the synthesis of flavones and aurones
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A metal-free synthesis for the preparation of sterically demanding ortho-demethylated ynones from mixed anhydrides and potassium alkynyltrifluoroborate salts has been developed. The one-pot reaction proceeds rapidly in the presence of a Lewis acid without the exclusion of air and moisture. This method is advantageous in that it is operationally simple, proceeds under mild conditions, and has a broad substrate scope. 2,6-Dimethoxy substituted anhydrides afford the corresponding mono-demethylated ynone products in good yields. In particular, 2-hydroxy substituted ynone products are valuable synthetic intermediates because their conversion to biologically active natural product scaffolds is straightforward. Flavones were obtained via 6-endo cyclization of the o-alkynyoylphenol intermediates under acidic conditions. Cesium carbonate was found to promote rapid 5-exo cyclization to furnish aurone products.
- Taylor, Cassandra,Bolshan, Yuri
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supporting information
p. 4392 - 4396
(2015/06/22)
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- New developments in the synthesis of (e)-8-styrylflavones
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A novel route for the synthesis of new (E)-8-styrylflavones is reported. This methodology involves the regio- and stereoselective Heck cross-coupling reaction of 8-iodoflavones and styrene derivatives. The Heck precursors, 8-iodoflavones, were obtained through an efficient regioselective one-pot oxidative cyclization-iodination reaction of (E)-2′-hydroxychalcones by applying the iodine/dimethyl sulfoxide system.
- De Azevedo, Orlando D. C. C.,Seixas, Raquel S. G. R.,Silva, Artur M. S.
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p. 1379 - 1384
(2015/06/16)
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- Structure-activity relationship study of biflavonoids on the dengue virus polymerase DENV-NS5 RdRp
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Dengue virus is the worlds most prevalent human pathogenic arbovirus. There is currently no treatment or vaccine, and solutions are urgently needed. We previously demonstrated that biflavonoids from Dacrydium balansae, an endemic gymnosperm from New Caledonia, are potent inhibitors of the Dengue virus NS5 RNA-dependent RNA polymerase. Herein we describe the structure-activity relationship study of 23 compounds: biflavonoids from D. balansae (1-4) and from D. araucarioides (5-10), hexamethyl-amentoflavone (11), cupressuflavone (12), and apigenin derivatives (13-23). We conclude that 1) over the four different biflavonoid skeletons tested, amentoflavone (1) and robustaflavone (5) are the most promising ones for antidengue drug development, 2) the number and position of methyl groups on the biflavonoid moiety modulate their inhibition of Dengue virus NS5 RNA-dependent RNA polymerase, and 3) the degree of oxygenation of flavonoid monomers influences their antidengue potential. Sotetsuflavone (8), with an IC50 = 0.16 μM, is the most active compound of this series and is the strongest inhibitor of the Dengue virus NS5 RNA-dependent RNA polymerase described in the literature. Georg Thieme Verlag KG Stuttgart New York.
- Coulerie, Paul,Nour, Mohammed,Maciuk, Alexandre,Eydoux, Cecilia,Guillemot, Jean-Claude,Lebouvier, Nicolas,Hnawia, Edouard,Leblanc, Karine,Lewin, Guy,Canard, Bruno,Figadere, Bruno
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p. 1313 - 1318
(2013/10/22)
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- Total synthesis of apigenin
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An efficient method for the synthesis of apigenin (4',5,7- trihydroxyflavone, a traditional medicine) from phloroglucinol and anisaldehyde has been developed. This transformation features a green method for hydroxyl protection as methyl ethers and a different way for cyclisation using iodine in DMSO. The overall yield of 40% is satisfactory.
- Wang, Jin,Zhou, Rong-Guang,Wu, Ting,Yang, Tao,Qin, Qi-Xue,Li, Li,Yang, Bo,Yang, Jian
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experimental part
p. 121 - 122
(2012/09/21)
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- Solution phase synthesis of a combinatorial library of chalcones and flavones as potent cathepsin v inhibitors
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Cathepsin V is a papain-like cysteine protease. It is involved in the control of human T cells (responsible for cell immunity), and presents the largest elastolytic activity among the proteolytic enzymes. Therefore, cathepsin V is a potential molecular ta
- Alvim, Joel,Severino, Richele P.,Marques, Emerson F.,Martinelli, Ariane M.,Vieira, Paulo C.,Fernandes, Joao B.,Da Silva, M. Fatima Das G. F.,Correa, Arlene G.
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experimental part
p. 687 - 695
(2010/11/18)
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- Divergent approach to flavones and aurones via dihaloacrylic acids. unexpected dependence on the halogen atom
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The reaction of phenols with 7a led to the synthesis of aurones, while the reaction of phenols with 7b led to the synthesis of flavones.
- Kraus, George A.,Gupta, Vinayak
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supporting information; experimental part
p. 5278 - 5280
(2011/02/21)
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- Synthesis and preliminary biological evaluation of chrysin derivatives as potential anticancer drugs
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A series of chrysin derivatives were prepared from 2-hydroxyacetophenone, 2,4-dihydroxyacetophenone, 2,4,6-trihydroxy- acetophenone, using modified Baker-Venkataraman transformation. Their anticancer activities in vitro were evaluated by the standard MTT method. The results of biological test showed that some of chrysin derivatives showed stronger anticancer activity than 5-fluorouracil.
- Zheng, Xing,Zhao, Fei Fei,Liu, Yun Mei,Yao, Xu,Zheng, Zi Tong,Luo, Xing,Liao, Duan Fang
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scheme or table
p. 6 - 8
(2011/10/31)
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- COMPOSITIONS AND METHODS FOR POTENTIATING ANTIBIOTIC ACTIVITY
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[205] The present invention provides compounds that potentiate the activity of antibiotic agents, particularly quinolones such as norflaxin. The invention further provides compositions, e.g., pharmaceutical compositions, comprising the inventive compounds. The invention also provides compositions comprising an antibiotic (e.g., a quinolone) and a compound that potentiates activity of the antibiotic. The invention further provides methods of treating a subject comprising administering any of the inventive compounds or compositions to the subject. The invention also provides screening methods to identify compounds that potentiate the activity of an antibiotic, e.g., a quinolone.
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- Structural basis for the activity of the RSK-specific inhibitor, SL0101
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Inappropriate activity of p90 ribosomal S6 kinase (RSK) has been implicated in various human cancers as well as other pathologies. We previously reported the isolation, characterization, and synthesis of the natural product kaempferol 3-O-(3″,4″-di-O-acetyl-α-l-rhamnopyranoside), termed SL0101 [Smith, J. A.; Poteet-Smith, C. E.; Xu, Y.; Errington, T. M.; Hecht, S. M.; Lannigan, D. A. Cancer Res., 2005, 65, 1027-1034: Xu, Y.-M; Smith, J. A.; Lannigan, D. A.; Hecht, S. M. Bioorg. Med. Chem., 2006, 14, 3974-3977: Maloney, D. J.; Hecht, S. M. Org. Lett., 2005, 7, 1097-1099]. SL0101 is a potent and specific inhibitor of RSK; therefore, we performed an analysis of the structural basis for the inhibitory activity of this lead compound. In in vitro kinase assays we found that acylation of the rhamnose moiety and the 4′, 5, and 7-hydroxyl groups are responsible for maintaining a high affinity interaction of RSK with SL0101. It is likely that the hydroxyl groups facilitate RSK binding through their ability to form hydrogen bonds. To determine whether the SL0101 derivatives were specific for inhibition of RSK we analyzed their ability to preferentially inhibit the growth of the human breast cancer line, MCF-7, compared to the normal human breast line, MCF-10A. We have previously validated this differential growth assay as a convenient readout for analyzing the specificity of RSK inhibitors [Smith, J. A.; Maloney, D. J.; Clark, D. E.; Xu, Y.-M.; Hecht, S. M.; Lannigan, D. A. Bioorg. Med. Chem., 2006, 14, 6034-6042]. We found that acylation of the rhamnose moiety was essential for maintaining the selectivity for RSK inhibition in intact cells. Further, the efficacy of SL0101 in intact cells is limited by cellular uptake as well as possible hydrolysis of the acetyl groups on the rhamnose moiety by ubiquitous intracellular esterases. These studies should facilitate the development of a RSK inhibitor, based on the SL0101 pharmacophore, as an anti-cancer chemotherapeutic agent.
- Smith, Jeffrey A.,Maloney, David J.,Hecht, Sidney M.,Lannigan, Deborah A.
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p. 5018 - 5034
(2008/03/12)
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- Silica gel supported InBr3 and InCl3: New catalysts for the facile and rapid oxidation of 2′-hydroxychalcones and flavanones to their corresponding flavones under solvent free conditions
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Silica gel supported InBr3 or InCl3 (15-20 mol %) were explored as a new solid-support catalysts for the facile and efficient oxidation, under solvent free conditions, of 2′-hydroxychalcones and flavanones to yield the corresponding flavones in >80% yield. The catalysts are easily prepared, stable, and efficient under mild reaction conditions.
- Ahmed, Naseem,Ali, Hasrat,Van Lier, Johan E.
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p. 253 - 256
(2007/10/03)
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- Formation of the unexpected 3-alkylated flavonoids in the alkylation of B-ring substituted 5,7-dihydroxy flavones
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Treatment of B-ring substituted 5,7-dihydroxy flavones with alkyl halides in the presence of potassium carbonate gave unexpected 3-alkylated flavonoids. Related experiments were carried out to explain the formation of 3-alkylated flavonoids and a ring opening followed by alkylation and ring closure mechanism was proposed.
- Wang, Cai-Ling,Zheng, Xing,Meng, Wei-Dong,Li, Hong-Qi,Qing, Feng-Ling
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p. 5399 - 5402
(2007/10/03)
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- Total synthesis of kaempferol and methylated kaempferol derivatives
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Kaempferol (1), a natural product from various plants, was synthesized in which the longest linear sequence is only seven steps in overall yields of 47% from commercially available 1,3,5-trimethoxybenzene (10). The methylated kaempferols 2-5 were also prepared by use of this concise synthetic methodology. The key transformations in this synthesis involved the I2 oxidative-promoting-cyclization and DDO oxidative hydroxylation. Several strategies to achieve 1 are provided.
- Lee, Yean-Jang,Wu, Tsao-Dong
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p. 201 - 206
(2007/10/03)
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- An environmentally benign synthesis of aurones and flavones from 2′-acetoxychalcones using n-tetrabutylammonium tribromide
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A wide variety of aurones (3a-f) can be prepared exclusively from 2′-acetoxychalcones (1a-f) in high yields in two steps, by bromination using n-tetrabutylammonium tribromide (TBATB) in the presence of CaCO3 in CH2Cl2-MeOH (5:2) at 0-5°C followed by cyclization of the brominated products 2a-f on treating with 0.2 M ethanolic KOH solution at 0-5°C, respectively. In contrast various flavone derivatives 6a-f can be obtained exclusively from compounds 1a-f in fairly good yields, by brominating with the same reagent in CH2Cl2, followed by dehydrobromination and finally cyclization on treating with 0.1 M NaOMe solution.
- Bose, Gopal,Mondal, Ejabul,Khan, Abu T,Bordoloi, Manob J.
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p. 8907 - 8909
(2007/10/03)
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- Total synthesis of robustaflavone, a potential anti-hepatitis B agent
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Robustaflavone, a naturally occurring compound, is an inhibitor of hepatitis B virus replication in vitro. Robustaflavone is a biflavanoid composed of two units of apigenin (5,7,4'-trihydroxyflavone) joined via a biaryl linkage between the 6-position of one unit and the 3'-position of the other (I6,II3'-biapigenin). The natural material was isolated from the seed- kernels of Rhus succedanea. To provide ready access to sufficient quantities of material for continued biological studies, as well as to provide a general route for the preparation of structural analogues, a total synthesis of robustaflavone was pursued. The total synthesis was approached by constructing apigenin ethers containing functionalities at the 6- and 3'- positions which could be cross-coupled using transition metal catalysis. Key steps of the synthesis included development of a regioselective iodination of an apigenin derivative at the 6-position. Also key was the formation of an apigenin 3'-boronate using a palladium-catalyzed exchange of the corresponding 3'-iodide with a diboron reagent. Finally, identification of appropriate reaction conditions for Suzuki coupling to form the sterically congested 6-3''' biaryl bond of robustaflavone provided access to the desired biflavanoid system. This work represents the first total synthesis of robustaflavone.
- Zembower, David E.,Zhang, Heping
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p. 9300 - 9305
(2007/10/03)
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- An efficient conversion of 2'-hydroxychalcones into flavanones: Use of tetra-n-butylammonium iodide
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2'-Hydroxychalcones 1 possessing different substitution patterns in rings A and B, have been found to undergo efficient isomerization to the corresponding flavanones 2 when heated in ethanol with hydrochloric acid and tetra-n-butylammonium iodide.
- Dhawan, Deepika,Grover, S. K.
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- Taste modifier and a method of modifying taste
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Taste modifier comprising a flavone derivative as an active ingredient of the general formula (I): STR1 wherein R1, R3, R4, R6 and R8 are independently a methoxy group or an hydrogen atom, R2 and R7 are methoxy groups, and R5 is a methoxy group or an hydroxy group, and a method of modifying taste, comprising adding a taste-modifying effective amount of the flavone derivative (I) to a product used in a mouth or an orally ingestible product. Various factors associated with taste can be modified, for example, the derivative can enhance sourness, reduce saltiness, inhibit unpleasant lasting of sweetness, enhance refreshing flavor and its continuity, reduce flavor associated with acetic acid, and enhance body, deliciousness and savor associated with the combination of these tastes.
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- Cyclodehydrogenation of 2'-Hydroxychalcones with Hypervalent Iodine Reagent: A New Synthesis of Flavones
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A new synthesis of chrysin (1) and luteolin (4) was accomplished by the cyclodehydrogenation of the appropriately substituted 2'-hydroxychalcones 21 and 22 in the presence of iodosobenzene diacetate/potassium hydroxide in methanol.The scope and limitation of this transformation is discussed. - Keywords: Cyclodehydrogenation / 2'-Hydroxychalcones / Flavones / Iodosobenzene diacetate
- Litkei, Gyoergy,Gulasci, Katalin,Antus, Sandor,Blasko, Gabor
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p. 1711 - 1716
(2007/10/02)
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- An efficient conversion of 2'-hydroxychalcones to flavones
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2'-Hydroxychalcones have been found to undergo smooth conversion to flavones when heated with sodium periodate in dimethyl sulphoxide.
- Hans,Grover
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p. 1021 - 1023
(2007/10/02)
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- ONE-STEP CONVERSION OF FLAVANONES INTO ISOFLAVANONES: A NEW FACILE BIOMIMETIC SYNTHESIS OF ISOFLAVONES
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One-step chemical conversion of flavanones into isoflavones by use of thallium trinitrate (TTN) is reported, and the mechanism of a 2,3-aryl migration in this reaction is discussed in relation to in vivo rearrangement process of flavanone precursors in the isoflavone biosynthesis.
- Kinoshita, Takeshi,Ichinose, Koji,Sankawa, Ushio
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p. 7355 - 7356
(2007/10/02)
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- Synthesis of a New Flavone
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The structure of the naturally occuring flavone 5-O-methylacacetin (I) has been confirmed by its synthesis. 5,7-Di-O-methylacacetin has been synthesised.
- Srivastava, Savitri D.,Srivastava, Santosh K.
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- Dehydrogenation of Flavanoids with the Iodine-Dimethyl Sulphoxide-Sulphuric Acid Reagent Systemm.
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A new synthetic application of the I2-Me2SO-H2SO4 reagent system for the high yield dehydrogenation of various flavanoid systems is described.
- Fatma, Waseem,Iqbal, Jawaid,Manchanda, Veena,Shaida, Waris A.,Rahman, Wasiur
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p. 2656 - 2671
(2007/10/02)
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- A One Step Synthesis of 3-Iodoflavones from 2'-Hydroxychalcones
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Syntheses of 3-iodo-5,7,4'-trimethoxyflavone (2) and 3-iodo-7,4'-dimethoxyflavone (4) in one step from 2'-hydroxy-4,4',6'-trimethoxychalcone (1) and 2'-hydroxy-4,4'-dimethoxychalcone (3), respectively, using I2-DMSO-H2SO4 reagent system are described.
- Iqbal, Jawaid,Fatma, Waseem,Shaida, Waris A.,Rahman, Wasiur
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p. 1001 - 1011
(2007/10/02)
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- NIVYASIDE - A NEW GLYCOSIDE FROM Leucanthemum vulgare
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From the ligulate flowers of Leucanthemum vulgare Lam. growing on the territory of the Georgian SSR a new glycoside has been isolated which has been called nivyaside and has the structure 8-(1-α-D-glucopyranosyl-5-deoxyquercit-5-yl)-4',5,7-trihydroxyflavone.
- Sagareishvili, T. G.,Alaniya, M. D.,Kikoladze, V. S.,Kemertelidze, E. P.
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p. 408 - 412
(2007/10/02)
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- STRUCTURAL ELUCIDATION OF POLYMETHOXYFLAVONES FROM SHIFT REAGENT PROTON NMR MEASUREMENTS
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Key Word Index - Polymethoxyflavones; 1H NMR; shift reagents; Pr(fod)3; structural elucidation. The quantitative shift reagent behavior of polymethoxylated flavones in the presence of Pr(fod)3 shows that for structural elucidation of these molecules the degree of substitution on the neighbourhood of the carbonyl group can be determined from the number of signals that are strongly shifted and broadened.The induced shifts of the remaining signals are of complementary help and even the resonances of individual methoxy groups can be ascribed.
- Joseph-Nathan, P.,Abramo-Bruno, D.,Torres, Ma. A.
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p. 313 - 318
(2007/10/02)
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- Prenylation of Apigenin
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Apigenin (I) on prenylation with 2-methylbut-3-ene-2-ol affords two major and four minor products.The major products are characterized as 6-C-prenylapigenin (II) and 5,4'-dihydroxy-6'',6''-dimethyl-4'',5''-dihydropyranoflavone (III) and the minor products as 7-O-prenylapigenin (IV), 5,4'-dihydroxy-6'',6''-dimethyl-5''-C-prenyl-4'',5''-dihydropyranoflavone (V), 5,4'-dihydroxy-6'',6''-dimethyl-4'',5''-dihydropyranoflavone (VI) and 5,4'-dihydroxy-6'',6''-dimethyl-5''-C-prenyl-4'',5''-dihydropyranoflavone (VII).Prenylation of apigenin with prenyl bromide in presence of methanolic sodium methoxide yields two major products, identified as 6,8-di(C-prenyl)apigenin (VIII) and 6-C-prenylapigenin (II), and four minor products, viz. 7,4'-di-O-prenylapigenin (IX), 8-C-prenyl-5,4'-dihydroxy-6'',6''-dimethyl-4'',5''-dihydropyranoflavone (X), 7-O-prenylapigenin (IV) and 5,4'-dihydroxy-6'',6''-dimethyl-4'',5''-dihydropyranoflavone (VI).Apigenin has been synthesized by a new route in a better yield.
- Roy, D,Khanna, R. N.
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p. 583 - 586
(2007/10/02)
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- Some Novel Photochemical and Related Aryl Couplings and Migrations in Flavonoid Synthesis
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2'-Methoxymethoxy-4,4',6'-trimethoxychalcone epoxide couples at the β-position with 3,5-dimethoxyphenol under photolytic conditions to form isomeric 1,3,3-triaryl-2-hydroxypropiophenones.These propiophenones are subject to photo-induced α-ketol rearrangements yielding isomeric 1-hydroxypropan-2-ones.Together these serve as useful synthetic intermediates for 4-arylflavan-3-ones and novel 2-hydroxy-2-arylbenzylbenzofuran-3(2H)-ones and 4-aryl-3-hydroxy-3,4-cis-dihydrocoumarins.The same epoxide reacts ionically under ambient conditions with 2,4,6-trihydroxybenzoic acid to afford a 3-O-benzoylpropiophenone intermediate, which provides novel access to isoflavones in high overall yield.Analogous coupling of phloroglucinol to epoxycinnamates gives diastereoisomeric 3,3-diaryl-2-hydroxypropionates which serve as precursors for 3,4-trans- and 3,4-cis-4-aryl-3-hydroxydihydrocoumarins and thence for 3-aryl- and 3-hydroxycoumarins.
- Westhuizen, Jan H. van der,Ferreira, Daneel,Roux, David G.
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p. 2856 - 2865
(2007/10/02)
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