- Preparation of thioflavones via thiophosphoryl chloride mediated cyclodehydration and thionation of 1-(2-hydroxyphenyl)-3-arylpropane-1,3-diones
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A simple and convenient one-pot strategy for the preparation of thioflavones from 1,3-diketones is described. Cyclodehydration of a range of β-diketones and thionation of the resulting flavones was achieved using thiophosphoryl chloride (PSCl3) which serves as both a catalyst and thionating agent. Georg Thieme Verlag Stuttgart · New York.
- Vimal, Manorama,Pathak, Uma,Pandey, Lokesh Kumar,Suryanarayana, Malladi V. S.
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experimental part
p. 30 - 32
(2011/02/26)
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- Hg2+-selective fluorogenic chemodosimeter based on naphthoflavone
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A new Hg2+-selective chemodosimeter based on α-naphthoflavone was investigated. The chemodosimetric behavior is based on the Hg2+-triggered desulfurization of flavothione into its oxygen analogue flavone. The signaling was effective in aqueous environment and the selective signaling was not affected in the presence of common physiologically and environmentally important metal ions.
- Namgoong, Ji Eun,Jeon, Hye Lim,Kim, Youn Hwan,Choi, Myung Gil,Chang, Suk-Kyu
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supporting information; experimental part
p. 167 - 169
(2010/03/04)
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- A new series of flavones, thioflavones, and flavanones as selective monoamine oxidase-B inhibitors
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A new series of synthetic flavones, thioflavones, and flavanones has been synthesized and evaluated as potential inhibitors of monoamine oxidase isoforms (MAO-A and -B). The most active series is the flavanone one with higher selective inhibitory activity against MAO-B. Some of these flavanones (mainly the most effective) have been separated and tested as single enantiomers. In order to investigate the MAOs recognition of the most active and selective compounds, a molecular modeling study has been performed using available Protein Data Bank (PDB) structures as receptor models for docking experiments.
- Chimenti, Franco,Fioravanti, Rossella,Bolasco, Adriana,Chimenti, Paola,Secci, Daniela,Rossi, Francesca,Yá?ez, Matilde,Orallo, Francisco,Ortuso, Francesco,Alcaro, Stefano,Cirilli, Roberto,Ferretti, Rosella,Sanna, M. Luisa
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experimental part
p. 1273 - 1279
(2010/04/24)
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- NMR of a series of novel hydroxyflavothiones
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Alkylated hydroxyflavothiones, namely flavothione, 5-hydroxyflavothione, 5,7-dihydroxyflavothione (chrysinthione), 7-dodecyloxy-5-hydroxyflavothione, 7-butyloxy-5-hydroxyflavothione, 2′,3,4′,7-tetramethoxy-5- hydroxyflavothione, 3,3′,4′,7-tetramethoxy-5-hydroxyflavothione, 7-butyloxy-4′,5-dihydroxyflavothione and 7-butyloxy-4′,5- hydroxyflavanonethione have been synthesized from the corresponding hydroxyflavones in two steps, alkylation of the non-hydrogen-bonded hydroxyl groups by bromoalkanes or dimethyl sulfate followedby conversion of the carbonyl group to a thione using Lawesson's Reagent undermicrowave irradiation and solvent-free conditions. Part of the alkylated flavanone, 7-butyloxy-4′,5- dihydroxyflavanone, was oxidized during the treatment with Lawesson's reagent to yield a second product 7-butyloxy-4′,5-dihydroxyflavothione in addition to the target product butyloxy-4′,5-hydroxyflavanonethione. Deuterium isotope effects on 13C chemical shifts have been measured in hydroxyflavones, isoflavones, flavanones and the thio analogs. Formal four-bond deuterium isotope effects on 13C chemical shifts, nΔC= S(OD) are very sensitive to variations in structures and substitution patterns. Density functional theory (DFT) calculations are carried out to obtain geometries. Correlations relating distances around the hydrogen bond system to the deuterium isotope effects on 13C chemical shifts are discussed. 13C chemical shifts are calculated by DFT methods. Effects of thiocarbonyl anisotropies are suggested.
- Nguyen, Tuyen Kim Pham,Nguyen, Kim Phi Phung,Kamounah, Fadhil S.,Zhang, Wei,Hansen, Poul Erik
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experimental part
p. 1043 - 1054
(2010/08/05)
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- Synthesis and antibacterial activity of substituted flavones, 4-thioflavones and 4-iminoflavones
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Synthesis of flavones, 4-thioflavones and 4-iminoflavones was carried out with the substitution of variable halogens, methyl, methoxy and nitro groups in the A, B and AB rings of the respective compounds and we also report here their antibacterial activity. Most of the synthesized compounds were found to be active against Escherichia coli, Bacillus subtilis, Shigella flexnari, Salmonella aureus, Salmonella typhi and Pseudomonas aeruginosa. Activity of 4-thioflavones and 4-iminoflavones was found to be higher than that of their corresponding flavone analogues. Investigated compounds having substituents like F, OMe and NO2 at 4′-position in ring-B exhibited enhanced activity and the presence of electronegative groups in the studied compounds showed a direct relationship to the antibacterial activity.
- Ullah Mughal, Ehsan,Ayaz, Muhammad,Hussain, Zakir,Hasan, Aurangzeb,Sadiq, Amina,Riaz, Muhammad,Malik, Abdul,Hussain, Samreen,Choudhary, M. Iqbal
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p. 4704 - 4711
(2007/10/03)
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- A facile and cheap method for the conversion of flavones into 4-thioflavones using phosphorus pentasulfide and sodium hydrogen carbonate
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A facile, rapid, high yielding and relatively cheaper method has been developed for the synthesis of 4-thioflavones by using phosphorus pentasulfide and sodium hydrogen carbonate. Seven new and five known substituted 4-thioflavones prepared by this method are reported.
- Mughal, Ehsan Ullah,Hasan, Aurangzeb,Rasheed, Lubna
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p. 445 - 450
(2007/10/03)
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- Photophysical properties of hydroxy-substituted flavothiones
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Flavothione and a number of synthesized hydroxy- (mono- and di-) substituted flavothiones have been thoroughly examined, particularly regarding their absorption, emission, photophysical (triplet yields and lifetimes), and oxygen-photosensitizing characteristics. These were all studied as a function of the nature of the solvent (four), which was particularly critical in terms of aiding in determining the energy and configurational nature of the lowest triplet state as well as the mechanism of intersystem crossing. Theoretical calculations were also performed. Both the location and number of hydroxyl groups have a substantial impact on the nature of the lowest excited triplet state as well as on the relative location of the two lowest excited singlet and triplet states. These in turn affect the magnitude and even the existence of triplet-state occupation as well as the ability to sensitize oxygen (to singlet oxygen). Three groups of compounds exist as characterized by the configurational nature of the triplet and the mechanism of intersystem crossing, or the essential absence of intersystem crossing altogether. The quantum yield of singlet oxygen formation is high for one group where the T(π, π*) state is lowest and generally high in another group where the T(n, π*) state is lowest, except in ethanol where competitive H-atom abstraction occurs. The potential of all hydroxy compounds as photosensitizers is evaluated.
- Elisei, Fausto,Lima, Joao C.,Ortica, Fausto,Aloisi, Gian G.,Costa, Manuela,Leitao, Emilia,Abreu, Isabel,Dias, Antonio,Bonifacio, Vasco,Medeiros, Jorge,Macanita, Antonio L.,Becker, Ralph S.
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p. 6095 - 6102
(2007/10/03)
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- Microwave-accelerated solvent-free synthesis of thioketones, thiolactones, thioamides, thionoesters, and thioflavonoids
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Formula presented An expeditious, solvent-free, and high yield conversion of ketones, flavones, isoflavones, lactones, amides, and esters to the corresponding thio analogues is described utilizing Lawesson's reagent in a process that circumvents the use of dry solvents and excess of the reagent.
- Varma, Rajender S.,Kumar, Dalip
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p. 697 - 700
(2008/02/11)
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- Synthesis and biological evaluation of flavonoids and related compounds as gastroprotective agents
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Several analogs of the gastroprotective molecule flavone have been synthesized and evaluated for gastroprotective activity. A C2-C3 double bond and an intact C ring appear necessary for optimum activity. Activity can be retained by replacing the 2-phenyl substituent with other groups but is eliminated when this ring is moved from the 2- to the 3-position.
- Ares, Jeffrey J.,Outt, Pamela E.,Randall, Jared L.,Johnston, Jeffrey N.,Murray, Peter D.,O'Brien, Linda M.,Weisshaar, Pamela S.,Ems, Beth L.
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p. 995 - 998
(2007/10/03)
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- Photochemical reactions of bianthrone and related substances
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Photocleavage reactions of a wide range of ethylene compounds were investigated. Photosensitized oxygenation resulted in formation of their corresponding ketones. On the other hand, photoreaction of these substrates with elemental sulfur yielded the corresponding thioketones. Furthermore, photobehaviour of some ethylene episulfides also was studied. It could be concluded that UV-irradiation provides a rapid and effective desactivation pathway for this class of compounds.
- Abdou, Wafaa M.,Elkhoshnieh, Yehia O.,Sidky, Mahmoud M.
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p. 3595 - 3602
(2007/10/02)
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- ORGANOPHOSPHORUS CHEMISTRY, 20. THE BEHAVIOUR OF CERTAIN γ-PYRONE DERIVATIVES TOWARD 2,4-BIS-(4-METHOXYPHENYL)-1,3,2,4-DITHIAPHOSPHETAN-2,4-DISULPHIDE (LAWESSON REAGENT)
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Lawesson reagent LR, 1 converts 2,6-dimethyl-γ-pyrone 2a, flavone 3a into their corresponding thioketones 2b and 3b in high yields.Thiation of flavone 3a with Lawesson reagent LR, 1 can be also induced photochemically to give thioflavone 3b together with the ring phosphorane product 6A.Thiation of khellin 4a by LR to give 4b is accompanied by demethylation of 4b to give desmethylthiokhellin 4c.The behaviour of γ-pyrones 2a, 3a and 4a toward thiation with LR, 1 was discussed in the light of the principle of vinylogy.
- Hafez, Taghrid S.,El-Khoshnieh, Yehia O.,Mahran, Mohamed R.,Atta, Sanaa M. S.
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p. 165 - 171
(2007/10/02)
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- ORGANOPHOSPHORUS COMPOUNDS ACTION OF 2,4-BIS-(4-METHOXYPHENYL)-1,3,2,4-DITHIADIPHOSPHETANE-2,4-DISULFIDE (LAWESSON REAGENT) AND 2,4-BIS-(PHENYLTHIO)-1,3-DITHIA-2,4-DIPHOSPHETANE-2,4-DISULFIDE (JAPANESE REAGENT) ON FLAVONE, α-NAPHTHOFLAVONE AND β-NAPHTHOFLAVONE
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Japanese reagent JR, 1b converts 2-phenyl-(5,6-benz)-γ-pyrone (flavone, 2a) into 2-phenyl-5,6-benzpyrane-4-thione 2b.Lawesson reagent LR, 1a converts 2-phenyl-7,8-benzo-1,4-chromone (α-naphthoflavone, 3a) and 2-phenyl-5,6-benzo-1,4-chromone (β-naphthoflavone 4a) into their corresponding thioketones 3b and 4b respectively.Thiation of 3a and 4a with Lawesson reagent, 1a can be induced photochemically to give 3b and 4b.Thiation of α-naphthoflavone 3a and β-naphthoflavone 4a with Japanese reagent JR, 1b is accompanied with ring opening at the heterocyclic oxygen atom of the γ-pyrone ring, to yield products 5 and 6 respectively.The given structures were based upon analytical, chemical and spectroscopic results. Key words: Lawesson reagent; Japanese reagent; thiation; γ-pyrones.
- Hafez, Taghrid S.
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p. 249 - 253
(2007/10/02)
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