- Synthesis and antiproliferative activity of novel aminoalkylated flavones
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(Figure presented.) Naturally occurring 5-hydroxy-4',7-dimethoxyflavone (acacetin-7-O-methyl ether) was synthesized through dehydrogenation, glycoside hydrolysis, and selective O-methylation, using naringin as starting material. Two series of sixteen novel aminoalkylated flavones were synthesized from 5-hydroxy-4',7-dimethoxyflavone. Furthermore, antiproliferative activity of the compounds was evaluated in vitro on a panel of three human cancer cell lines (HeLa, HCC1954, and SK-OV-3) using Cell Counting Kit-8 assay. The result showed that most of the synthetic compounds exhibited moderate to potent antiproliferative activities against the three human cancer cell lines with IC50 values of 6.95–64.50 μΜ.
- Yan, Lili,Liu, Haoran,Wang, Qiuan,Wang, Gangqiang
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- Syntheses and crystal structures of two apigenin alkylation derivatives
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Two apigenin alkylation derivatives, 4′,7-dimethoxyl-5-hydroxyflavone (I) and 4′,7-diethoxyl-5-hydroxyflavone (II), have been synthesized and their crystal structures were determined by 1H NMR and single crystal X-ray diffraction study. (I) is triclinic, space group P-1 with a = 7.120(5) A, b = 7.297(5) A, c = 13.559(10) A, α = 89.313(12)°, β = 86.298(12)°, γ = 83.999(13)° and Z = 2. (II) is monoclinic, space group P 21 /c with a = 16. 309(4) A, b = 7.303(2) A, c = 15.185(4) A, α = 90.00°, β = 115.70(2)°, γ = 90.00° and Z = 4. They have the same flavone skeleton which is composed of a benzopyranone moiety and a phenyl moiety. Molecules of (I) are linked into a two-dimensional network by a combination of C-H...O hydrogen bond and π-π stacking interactions. (II) shows some discrepancies with (I) and the molecules are linked into a column by π-π stacking interaction.
- Kou, Li-Qun,Cheng, Xin-Li,Zhang, Zun-Ting
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- Synthesis of Polymethoxyflavonoids from Hesperidin and Naringin and their Antiproliferative Activity
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[Figure not available: see fulltext.] A series of polymethoxyflavonoids were synthesized via cleavage of the glycosidic bond, dehydrogenation, selective methylation, bromination, nucleophilic aromatic substitution, O-prenylation, Claisen–Schmidt aldol condensation, cyclization, and oxidation from very abundant and inexpensive natural flavonoids hesperidin and naringin. The in vitro antiproliferative activity of the synthesized compounds was evaluated against a panel of four human cancer cell lines (Aspc-1, HCT-116, HepG-2, and SUN-5) by the CellTiter-Glo assay. The results showed that some of synthesized compounds exhibited moderate to high antiproliferative activity. Among them, (2E)-1-(2-hydroxy-3,4,5,6-tetramethoxyphenyl)-3-(7-methoxy-1,3-benzodioxol-5-yl)prop-2-en-1-one was revealed to be the most active with IC50 values ranging from 10.35 to 13.89 μM against all four cancer cell lines, the IC50 value (10.35 μM) being below positive control cisplatin (12.36 μM) against HepG-2 cells.
- Su, Liang,Jin, Zhizhong,Liu, Kexiong,Wang, Qiuan
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p. 100 - 105
(2022/03/27)
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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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- Silenerepin – a New C-Glycosylflavone from Silene repens
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The new C-glycosylflavone silenerepin or 5-hydroxy-7,4′-dimethoxyflavone-6,8-di-C-β-D-glucopyranoside and 20 known flavonoids were isolated from the herb Silene repens Patrin (Caryophyllaceae). Their structures were elucidated using UV, IR, and NMR spectroscopy and mass spectrometry.
- Olennikov
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p. 423 - 426
(2020/06/17)
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- Discovery of potent and selective acetylcholinesterase (AChE) inhibitors: acacetin 7-O-methyl ether Mannich base derivatives synthesised from easy access natural product naringin
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Naringin, as a component universal existing in the peel of some fruits or medicinal plants, was usually selected as?the material to synthesise bioactive derivates since it was easy to gain with low cost. In present investigation, eight new acacetin-7-O-methyl ether Mannich base derivatives (1–8) were synthesised from naringin. The bioactivity evaluation revealed that most of them exhibited moderate or potent acetylcholinesterase (AChE) inhibitory activity. Among them, compound 7 (IC50 for AChE?=?0.82?±?0.08?μmol?L?1, IC50 for BuChE?=?46.30?±?3.26?μmol?L?1) showed a potent activity and high selectivity compared with the positive control Rivastigmine (IC50 for AChE?=?10.54?±?0.86?μmol?L?1, IC50 for BuChE?=?0.26?±?0.08?μmol?L?1). The kinetic study suggested that compound 7 bind to AChE with mix-type inhibitory profile. Molecular docking study revealed that compound 7 could combine both catalytic active site (CAS) and peripheral active site (PAS) of AChE with four points (Trp84, Trp279, Tyr70 and Phe330), while it could bind with BuChE via only His 20.
- Liu, Hao-ran,Men, Xue,Gao, Xiao-hui,Liu, Lin-bo,Fan, Hao-qun,Xia, Xin-hua,Wang, Qiu-an
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p. 743 - 747
(2017/10/06)
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- Encoding matter with regiospecific 12C/13C isotopic labels
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Society suffers due to an inability to regulate matter. This study presents a practical tool for the encryption of materials by adjusting the levels of 13C at regiospecific atoms within a molecule to generate a stable-isotopically encoded signature. This system is demonstrated by securing a document by adapting natural product chemistry as an encryption device. This approach delivers a complex signal that would be difficult to intercept due to the need for access to extraction protocols, sophisticated NMR instrumentation and a vital level of prior knowledge. Overall, this discovery offers an important tool to monitor and track valuable entities on our planet.
- La Clair, James J.
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p. 2611 - 2614
(2018/03/21)
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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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p. 1610 - 1620
(2018/03/21)
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- Synthesis and Antiproliferative Activity of Thioxoflavones Mannich Base Derivatives
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Two series of 12 novel thioxoflavones Mannich base derivatives 5a–f and 6a–f were synthesized via Mannich reaction of 4′,7-dimethoxy-5-hydroxyflavothione (3) or 3′,4′,7-trimethoxy-5-hydroxyflavothione (4) with appropriate aliphatic amines or alicyclic amines and formaldehyde. Thioxoflavones 3 and 4 were prepared from 4′,7-dimethoxy-5-hydroxyflavone (1) and 3′,4′,7-trimethoxy-5-hydroxyflavone (2) with Lawesson's reagent, respectively. Their antiproliferative activities in vitro were evaluated on a panel of three human cell lines (HeLa, HCC1954, and SK-OV-3) by CCK-8 assay. The results showed that most of the thioxoflavones and their Mannich base derivatives exhibited potential antiproliferative activities on the tested cancer cell lines, with IC50 values ranging from 9.16 to 55.50 μM. In particular, thioxoflavone 4 and the thioxoflavone Mannich base derivatives 5a and 5d showed the best antiproliferative activity on all three human cancer cell lines; they are promising candidates worthy of further development. The structures of all synthesized compounds were confirmed by 1H NMR, 13C NMR, IR, and MS techniques.
- Li, Wei,Li, Xueli,Liu, Manhui,Wang, Qiuan
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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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- Activities of Wogonin Analogs and Other Flavones against Flavobacterium columnare
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In our on-going pursuit to discover natural products and natural product-based compounds to control the bacterial species Flavobacterium columnare, which causes columnaris disease in channel catfish (Ictalurus punctatus), we synthesized flavone and chalcone analogs, and evaluated these compounds, along with flavonoids from natural sources, for their antibacterial activities against two isolates of F. columnare (ALM-00-173 and BioMed) using a rapid bioassay. The flavonoids chrysin (1a), 5,7-dihydroxy-4′-methoxyflavone (11), isorhamnetin (26), luteolin (27), and biochanin A (29), and chalcone derivative 8b showed strong antibacterial activities against F. columnare ALM-00-173 based on minimum inhibition concentration (MIC) results. Flavonoids 1a, 8, 11, 13 (5,4′-dihydroxy-7-methoxyflavone), 26, and 29 exhibited strong antibacterial activities against F. columnare BioMed based upon MIC results. The 24-h 50% inhibition concentration (IC50) results revealed that 27 and 29 were the most active compounds against F. columnare ALM-00-173 (IC50 of 7.5 and 8.5 mg/l, resp.), while 26 and 29 were the most toxic compound against F. columnare BioMed (IC50 of 9.2 and 3.5 mg/l, resp.). These IC50 results were lower than those obtained for wogonin against F. columnare ALM-00-173 and F. columnare BioMed (28.4 and 5.4 mg/l, resp.). However, based on MIC results, none of the compounds evaluated in this study were as active as wogonin (MIC 0.3 mg/l for each F. columnare isolate). Further modification of the wogonin structure to enhance antibacterial is of interest.
- Tan, Cheng-Xia,Schrader, Kevin K.,Khan, Ikhlas A.,Rimando, Agnes M.
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p. 259 - 272
(2015/10/19)
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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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- Regioselective iodination of flavonoids by N-iodosuccinimide under neutral conditions
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Regioselective synthesis of C-6 and C-8 monoiodo flavonoids, which are important intermediates for the synthesis of flavonoid natural products and drug molecules, was achieved by iodination of suitably alkylated flavonoids with N-iodosuccinimide (NIS) in DMF. The iodination gives either a C-6 or C-8 iodo flavonoid in high yield, depending on the protection pattern of the C-5 and C-7 OH groups. The mild and neutral conditions render this novel protocol particularly useful for the regioselective iodination of acid-sensitive substrates.
- Lu, Kui,Chu, Jie,Wang, Haomeng,Fu, Xiaoli,Quan, Dewu,Ding, Hongxia,Yao, Qingwei,Yu, Peng
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supporting information
p. 6345 - 6348
(2013/11/06)
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- Efficient synthesis of scutellarein
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Scutellarein is a component of Scutellaria, recently known as a potent cytotoxic agent on human leukaemia cells. The aim of this study was the synthesis of scutellarein and its methylated derivative. The new features are the innovating method to afford flavones from flavanones and the A-ring regioselective bromination step that lead to the target molecule by a facile and high-yielding pathway.
- Righi, Giuliana,Silvestri, Ilaria Proietti,Barontini, Maurizio,Crisante, Fernanda,Di Manno, Andrea,Pelagalli, Romina,Bovicelli, Paolo
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experimental part
p. 1278 - 1284
(2012/09/25)
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- Structure-activity relationships of biflavonoids for β-secretase (BACE-1) inhibitory activity
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Bioactive natural products are useful sources of new pharmaceutics. Their analogues are also important for evaluating structure-activity relationships. In this study the structure-activity relationships of 2,3-dihydro-6-methylginketin (1) for BACE-1 inhibitory activity were studied. Biflavonoids consisting of flavanone and flavone, and also the presence of a methoxy group at the C-4' position, were found to be important for strong activity. 2,3-Dihydro-6- methylbilobetin (2) showed strong activity with an IC50 value of 0.56 μM.
- Sasaki, Hiroaki,Kitoh, Yuki,Miki, Kazuhiko,Kinoshita, Kaoru,Koyama, Kiyotaka,Kaneda, Miyuki,Takahashi, Kunio
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p. 2749 - 2756
(2013/01/15)
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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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- Use of Flavone Compounds as Potassium Channel Inhibitors
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This invention provides a method for treating or preventing human atrial arrhythmia (fibrillation) using the leading flavone compound acacetin, and its derivatives and analogues that inhibit the ultra-rapidly-activating delayed rectifier potassium current (IKur or IKsus), transient outward potassium (Ito), and acetylcholine-activated potassium current (IK.ACh).
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Page/Page column 11
(2008/12/08)
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- INHIBITION OF MONOCYTE SURVIVAL, DIFFERENTIATION, OR PROLIFERATION
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Methods comprising administering to the subject apigenin, an apigenin derivative, apigeni and at least one apigenin derivative, or a combination of apigenin derivatives are provided fo treating inflammation in a subject in need of the same.
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Page/Page column 9
(2008/06/13)
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- Semisynthesis of linarin, acacetin, and 6-iodoapigenin derivatives from diosmin
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Semisynthesis of linarin and acacetin from the Citrus flavonoid diosmin was performed via, as first intermediate, the 3′-O-phenyltetrazolyl ether of diosmin. This paper relates also a semisynthetic access to 6-iodoapigenin derivatives, which are key compounds in the synthesis of some biflavonoids such as robustaflavone.
- Quintin, Jerome,Lewin, Guy
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p. 1624 - 1627
(2007/10/03)
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- Structural requirements of flavonoids and related compounds for aldose reductase inhibitory activity
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The methanolic extracts of several natural medicines and medicinal foodstuffs were found to show an inhibitory effect on rat lens aldose reductase. In most cases, flavonoids were isolated as the active constituents by bioassay-guided separation, and among them, quercitrin (IC50=0.15 μM), guaijaverin (0.18 μM), and desmanthin-1 (0.082 μM) exhibited potent inhibitory activity. Desmanthin-1 showed the most potent activity, which was equivalent to that of a commercial synthetic aldose reductase inhibitor, epalrestat (0.072 μM). In order to clarify the structural requirements of flavonoids for aldose reductase inhibitory activity, various flavonoids and related compounds were examined. The results suggested the following structural requirements of flavonoid: 1) the flavones and flavonols having the 7-hydroxyl and/or catechol moiety at the B ring (the 3′,4′-dihydroxyl moiety) exhibit the strong activity; 2) the 5-hydroxyl moiety does not affect the activity; 3) the 3-hydroxyl and 7-O-glucosyl moieties reduce the activity; 4) the 2-3 double bond enhances the activity; 5) the flavones and flavonols having the catechol moiety at the B ring exhibit stronger activity than those having the pyrogallol moiety (the 3′,4′,5′-trihydroxyl moiety).
- Matsuda, Hisashi,Morikawa, Toshio,Toguchida, Iwao,Yoshikawa, Masayuki
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p. 788 - 795
(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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- 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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- A biomimetic approach to the synthesis of rocaglamide based on a photochemical [2 + 2] cycloaddition of a cinnamate unit to a flavone
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In attempting a biomimetic synthesis of rocaglamide, we have discovered the first examples of photochemically induced cycloaddition reactions involving a flavone system.
- Hailes,Raphael,Staunton
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p. 5313 - 5316
(2007/10/02)
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- O-methylation of flavonoids by cell-free extracts of calamondin orange
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Cell-free extracts of calamondin orange (Citrus mitis) catalysed the O-methylation of almost all hydroxyls of a number of flavonoids, indicating the existence in citrus tissues of ortho, meta, para and 3-O-methyltransferases. The latter, hitherto unreported enzyme, catalysed the formation of 3-O-methyl ethers of galangin and quercetin. The stepwise O-methylation of a number of compounds, especially quercetin and quercetagetin, tends to suggest a coordinated sequence of O-methylations on the surface of a multienzyme complex. The methyl acceptor abilities of the flavonoid substrates used are discussed in relation to their hydroxyl substitution patterns and their negative electron density distribution.
- Brunet, Gunter,Ibrahim, Ragai K.
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p. 741 - 746
(2007/10/02)
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