- 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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- Dichlororuthenium(IV) complex of meso-Tetrakis(2,6-dichlorophenyl) porphyrin: Active and robust catalyst for highly selective oxidation of arenes, Unsaturated steroids, and electron-deficient alkenes by using 2,6-dichloropyridine N-oxide
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[RuIV(2,6-Cl2tpp)Cl2], prepared in 90% yield from the reaction of [RuVI(2,6-Cl2tpp)O2] with Me3SiCl and structurally characterized by X-ray crystallography, is markedly superior to [RuIv(tmp)Cl2], [RuIV(ttp)Cl2], and [RuII(por)(CO)] (por = 2,6-Cl2tpp, F20-tpp, F28-tpp) as a catalyst for alkene epoxidation with 2,6-Cl2pyNO (2,6Cl2tpp = meso-tetrakis(2,6-dichlorophenyl)porphyrinato dianion; tmp = meso-tetramesitylporphyrinato dianion; ttp = meso-tetrakis(p-tolyl)porphyrinato dianion; F20-tpp = meso-tetrakis(pentafluorophenyl)porphyrinato dianion; F28-tpp = 2,3,7,8,12,13,17,18-octafluoro-5,10,15,20- tetrakis(pentafluorophenyl)-porphyrinato dianion). The "[Ru IV(2,6-Cl2tpp)Cl2] + 2,6-Cl 2pyNO" protocol oxidized, under acid-free conditions, a wide variety of hydrocarbons including 1) cycloalkenes, conjugated enynes, electron-deficient alkenes (to afford epoxides), 2) arenes (to afford quinones), and 3) Δ5-unsaturated steroids, Δ4-3- ketosteroids, and estratetraene derivatives (to afford epoxide/ketone derivatives of steroids) in up to 99% product yield within several hours with up to 100% substrate conversion and excellent regio- or diastereoselectivity. Catalyst [RuIv(2,6-Cl2tpp)Cl2] is remarkably active and robust toward the above oxidation reactions, and turnover numbers of up to 6.4 × 103, 2.0 × 104, and 1.6 × 104 were obtained for the oxidation of α,β-unsaturated ketones, arenes, and Δ5-unsaturated steroids, respectively.
- Zhang, Jun-Long,Che, Chi-Ming
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p. 3899 - 3914
(2007/10/03)
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- Cytotoxic 2',5'-dihydroxychalcones with unexpected antiangiogenic activity.
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A series of 2',5'-dihydroxychalcones were synthesized and evaluated for cytotoxicity against tumor cell lines and human umbilical venous endothelial cells (HUVEC). It was found that chalcones with electron-withdrawing substituents on the B ring exhibited potent cytotoxicity against a variety of tumor cell lines while compounds with electron-releasing groups were less potent in general. Those compounds with B ring replaced by extended or heteroaromatic rings exhibited significant bioactivity. Several compounds were shown to have marked cytotoxic selectivity towards HUVECs. Especially, among the synthesized compounds, 2-chloro-2',5'-dihydroxychalcone (2-3) showed the highest selectivity index up to 66 in comparison to HCT116 cells. This compound also exhibited strong inhibitory effects on the HUVEC tube formation in an in vitro model. When administered into BDF1 mice bearing Lewis lung carcinoma cells at 50 mg kg(-1) day(-1), 2-3 was found to inhibit the growth of tumor mass by 60.5%.
- Nam, Nguyen-Hai,Kim, Yong,You, Young-Jae,Hong, Dong-Ho,Kim, Hwan-Mook,Ahn, Byung-Zun
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p. 179 - 187
(2007/10/03)
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- 2',5'-Dihydroxychalcone as a potent chemical mediator and cyclooxygenase inhibitor
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Eleven chalcone derivatives have been tested for their inhibitory effects on platelet aggregation in rabbit platelet suspension and the activation of mast cells and neutrophils. Arachidonic acid-induced platelet aggregation was potently inhibited by almost all the compounds and some also had a potent inhibitory effect on collagen-induced platelet aggregation and cyclooxygenase. Some hydroxychalcone derivatives showed strong inhibitory effects on the release of β-glucuronidase and lysozyme, and on superoxide formation by rat neutrophils stimulated with the peptide fMet-Leu-Phe (fMLP). We found that the anti-inflammatory effect of 2',5'-dihydroxychalcone was greater than that of trifluoperazine. 2',5'-Dihydroxy and 2',3,4,4'-tetrahydroxyl chalcones, even at low concentration (50 μM), tested in platelet-rich plasma from man almost completely inhibited secondary aggregation induced by adrenaline. These results suggest that the anti-platelet effects of the chalcones are mainly a result of inhibition of thromboxane formation.
- Lin, Chun-Nan,Lee, Tai-Hua,Hsu, Mei-Feng,Wang, Jih-Pyang,Ko, Feng-Nien,Teng, Che-Ming
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p. 530 - 536
(2007/10/03)
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- A Novel and Convenient One-pot Synthesis of 3-Benzylidene-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-ones
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A novel and convenient one-pot synthesis of 3-benzylidene-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-ones from hydroxyacetophenones is described.It was also observed that the title compounds are the major side products in the Claisen-Schmidt chalcone synthesi
- Chawla, H. Mohindra,Sharma, S. Kumar
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p. 901 - 913
(2007/10/02)
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- NOVEL ONE POT CONVENIENT SYNTHESIS OF 3- BENZYLIDENE-2-PHENYL-2,3-DIHYDRO-4H-1-BENZOPYRAN-4-ONES
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A novel one pot good yield synthesis of 3-benzylidene-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-ones by the condensation of o-hydroxyacetophenones with aromatic aldehydes has been described and the new compounds were identified by their chemical, analytical and spectroscopic data.
- Chawla, H. Mohindra,Sharma, S. Kumar
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p. 1527 - 1534
(2007/10/02)
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