- Synthesis and evaluation of the thermal behavior of flavonoids: Thermal decomposition of flavanone and 6-hydroxyflavanone
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Flavonoids in the broad sense of the term are virtually universal plant pigments. Synthesis of flavanone and 6-hydroxyflavanone was carried out and identified by H and C NMR. Details concerning the thermal behavior were evaluated by thermogravimetry under oxygen and nitrogen purge gases. Additionally, the kinetic studies were evaluated from several heating rates (5, 10 and 20?°C?min?1) and sample mass of 2?mg in open crucibles. The obtained data were evaluated with the isoconversional method, where the values of activation energy (Ea/kJ?mol?1) were plotted in function of the conversion degree (α). The results of thermal behavior of the flavanone under a nitrogen purge gas showed that this compound has a homogeneous degradation process while the hydroxyl group in the aromatic ring of 6-hydroxyflavanone there are two mass losses.
- Ferreira, Leonardo Miziara Barboza,Kobelnik, Marcelo,Regasini, Luis Octavio,Dutra, Luiz Antonio,da Silva Bolzani, Vanderlan,Ribeiro, Clóvis Augusto
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- Flavanone-based fluorophores with aggregation-induced emission enhancement characteristics for mitochondria-imaging and zebrafish-imaging
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Fluorophores with aggregation-induced emission enhancement (AIEE) characteristics applied in bioimaging have attracted more and more attention in recent years. In this work, a series of flavanone compounds with AIEE characteristics was developed and applied to fluorescence imaging of mitochondria and zebrafish. The compounds were readily prepared by the thermal dehydration of chalcone that was obtained by the reaction of o-hydroxyacetophenone and benzaldehyde. Two of these compounds showed significant AIEE characteristics by fluorescence performance experiments, including optical spectra, fluorescence spectra, fluorescence quantum yield (?F), fluorescence lifetime, and scanning electron microscopy (SEM). Compared with traditional organic fluorescent dyes, these compounds have high fluorescence emission and high fluorescence quantum yield in solid or aggregated state, which overcomes the shortcoming of aggregation-caused quenching (ACQ). More importantly, the two compounds exhibited low cytotoxicity and good cytocompatibility in A549 lung cells at the experimental concentration range and they specifically targeted mitochondria, which make it of great potential use in mitochondria labeling. In addition, they were embryonic membrane permeable and had different affinities for different tissues and organs of zebrafish, but mainly distributed in the digestive system, providing a basis for the application of such compounds in bioimaging. These AIEE compounds with superior properties could be of great potential use in mitochondria imaging and other in vivo studies.
- He, Feng,Li, Na,Liu, Liyan,Luo, Huiqing,Wang, Huaqiao,Yang, Depo
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- Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids
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A total of 47 flavanones were expediently synthesized via one-pot β-arylation of chromanones, a class of simple ketones possessing chemically unactivated β sites, with arylboronic acids via tandem palladium(II) catalysis. This reaction provides a novel route to various flavanones, including natural products such as naringenin trimethyl ether, in yields up to 92percent.
- Cho, Yang Yil,Jang, Hyu Jeong,Kim, Dong Hwan,Kim, Nam Yong,Kim, Nam-Jung,Kim, Young Min,Lee, Soo Jin,Lee, Yong Sup,Park, Boyoung Y.,Son, Seung Hwan,Yoo, Hyung-Seok
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p. 10012 - 10023
(2019/08/30)
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- A novel synthesis of naringenin and related flavanones
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Efficient methods are reported for the preparation of naringenin (4',5,7-trihydroxyflavanone) which could be easily scaled-up. They have been applied to three other flavanones (6.hydroxyflavanone, 6,4'-dihydroxyflavanone, 6,3',4'-trihydroxyflavanone) suitably.
- Cui, Wei,Zhang, Ji,Wang, Qian,Gao, Kai,Zhang, Wei,Yang, Jian
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p. 686 - 689
(2015/02/19)
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- Enantioselective conversion of certain derivatives of 6-hydroxyflavanone
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In the culture of Aspergillus niger MB, three racemic flavonoid derivatives (6-acetoxy-, 6-propionoxy-, and 6-butyryloxyflavanone) undergo microbial transformations resulting in optically pure (-)-(S)-6,4′- dihydroxyflavanone formation. In turn, biotransf
- Kostrzewa-Suslow, Edyta,Dymarska, Monika,Bialonska, Agata,Janeczko, Tomasz
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- Regioselective hydroxylation of diverse flavonoids by an aromatic peroxygenase
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Aromatic peroxygenases are extracellular fungal biocatalysts that selectively oxidize a variety of organic compounds. We found that the peroxygenase of the fungus Agrocybe aegerita (AaeAPO) catalyzes the H 2O2-dependent hydroxylation of diverse flavonoids. The reactions proceeded rapidly and regioselectively yielding preferentially monohydroxylated products, e.g., from flavanone, apigenin, luteolin, flavone as well as daidzein, quercetin, kaempferol, and genistein. In addition to hydroxylation, O-demethylation of fully methoxylated tangeretin was catalyzed by AaeAPO. The enzyme was merely lacking activity on the quercetin glycoside rutin, maybe due to sterical hindrance by the bulky sugar substituents. Mechanistic studies indicated the presence of epoxide intermediates during hydroxylation and incorporation of H2O2-derived oxygen into the reaction products. Our results raise the possibility that fungal peroxygenases may be useful for versatile, cost-effective, and scalable syntheses of flavonoid metabolites.
- Barková, Kate?ina,Kinne, Matthias,Ullrich, René,Hennig, Lothar,Fuchs, Annett,Hofrichter, Martin
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experimental part
p. 4874 - 4878
(2011/08/03)
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- Microbial metabolism part 9.1 Structure and antioxidant significance of the metabolites of 5,7-dihydroxyflavone (chrysin), and 5- and 6-hydroxyflavones
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5,7-Dihydroxyflavone (chrysin) (1) when fermented with fungal cultures, Aspergillus alliaceous (ATCC 10060), Beauveria bassiana (ATCC 13144) and Absidia glauco (ATCC 22752) gave mainly 4′-hydroxychrysin (4), chrysin 7-O-β-D-4-O-methylglucopyranoside (5) and chrysin 7-sulfate (6), respectively. Mucore ramannianus (ATCC 9628), however, transformed chrysin into six metabolites: 4′-hydroxy-3′-methoxychrysin (chrysoeriol) (7), 4′-hydroxychrysin (apigenin) (4) 3′,4′-dihydroxychrysin (luteolin) (8), 3′-methoxychrysin 4′-O-α-D-6- deoxyallopyranoside (9), chrysin 4′-O-α-D-6-deoxyallopyranoside (10), and luteolin 3′-sulfate (11). Cultures of A. alliaceous (ATCC 10060) and B. bassiana (ATCC 13144) metabolized 5-hydroxyflavone (2) into 5,4′-dihydroxyflavone (12) and 4′-hydroxyflavone 5-O-β-D-4-O-methylglucopyranoside (13), respectively. 6-Hydroxyflavone (3) was transformed into 6-hydroxyflavanone (14), flavone 3-O-β-D-4-O- methylglucopyranoside (15) and (±)-flavanone 6-O-β-D-4-O- methylglucopyranoside (16) by cultures of Beauveria bassiana (ATCC 13144). The structures of the metabolic products were elucidated by means of spectroscopic data. The significance of the metabolites as antioxidants in relation to their structure is briefly discussed.
- Herath, Wimal,Mikell, Julie Rakel,Hale, Amber Lynn,Ferreira, Daneel,Khan, Ikhlas Ahmad
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experimental part
p. 418 - 422
(2009/04/11)
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- Preparative monohydroxyflavanone syntheses and a protocol for gas chromatography-mass spectrometry analysis of monohydroxyflavanones
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We describe a facile efficient, and preparative approach for monohydroxyflavanone syntheses. Using this protocol, a hydroxyl is regio-selectively introduced at one carbon of a flavanone A- or B-ring per synthesis. The seven possible isomers were each synthesized from the corresponding monomethoxymethoxylated 2′-hydroxychalcones in acidic solution. These monohydroxyflavanones were characterized using a gas chromatography-mass spectrometry (GC-MS) system that incorporated a DB-5 capillary column. Ours is the first report of a preparative synthetic method during which a single hydroxyl can be selectively added to a flavanone A- or B-ring at any position. We are also the first to develop a procedure that separates the seven isomers by GC and characterizes the mass spectra of the isomers. Both the synthetic method and the GC-MS conditions may become important tools during future flavanone metabolism and oxidation studies.
- Kagawa, Hitoshi,Shigematsu, Asako,Ohta, Shigeru,Harigaya, Yoshihiro
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p. 547 - 554
(2007/10/03)
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- SOME REACTIONS OF PHENYL-BISMETHANE
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As a result of condensing 2,5-dihydroxyacetophenone with benzoic aldehyde in an alkaline medium the not yet described phenyl-bismethane (1) was obtained.It has been shown that in reactions of compound 1 with hydroxylamine and hydrazine monooxime (2) and monohydrazone (4) are formed.The low stability of compound 1 has been found.
- Kamecki, Jerzy,Pijewska, Lucyna
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p. 791 - 796
(2007/10/02)
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