- Formation of 6-formyl-7-hydroxy-8-methoxycoumarin and 5,8-dioxopsoralen by reaction of 8-methoxypsoralen with H2O2 and potassium superoxide (KO2) catalyzed by halogenated or perhalogenated 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides
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The oxidation of 8-methoxypsoralen (2) with hydrogen peroxide and potassium superoxide catalyzed by 5,10,15,20-(2,4,6-trimethylphenyl)porphyrinatoiron(III) chlorides [Me12-TPPFe(III)Cl] (1a) and 5,10,15,20-(2,6-dichlorophenyl)porphyrinatoiron(III) chlorides [Cl8TPPFe(III)Cl] (1b) in dichloromethane gives 6-formyl-7-hydroxy-8-methoxycoumarin (3) in moderate yields, whereas the oxidation of (2) with H2O2 catalyzed by 5,10,15,20-(2,6-dichlorophenyl)-β-octahaloporphyrinatoiron(III) chlorides [Cl8βX8TPPFe(III)Cl] (X=Cl, Br) (1c, 1d) gives specifically 5,8-dioxopsoralen (4) in moderate yields.
- Chauhan,Sahoo,Mohapatra,Kalra,Gulati
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Read Online
- Structure-activity relationships for naturally occurring coumarins as β-secretase inhibitor
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The present study was demonstrated to evaluate the effects of naturally occurring coumarins (NOCs) including simple coumarins, furanocoumarins, and pyranocoumarins on the inhibition of β-secretase (BACE1) activity. Of 41 NOCs examined, some furanocoumarins inhibited BACE1 activity, but simple coumarins and pyranocoumarins did not affect. The most potent inhibitor was 5-geranyloxy-8-methoxypsoralen (31), which has an IC50 value of 9.9 μM. Other furanocoumarin derivatives, for example, 8-geranyloxy-5- methoxypsoralen (35), 8-geranyloxypsoralen (24), and bergamottin (18) inhibited BACE1 activity, with the IC50 values 25.0 μM. Analyses of the inhibition mechanism by Dixon plots and Cornish-Bowden plots showed that compounds 18, 31 and 35 were mixed-type inhibitor. The kinetics of inhibition of BACE1 by coumarins 24 was non-competitive inhibitors.
- Marumoto, Shinsuke,Miyazawa, Mitsuo
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supporting information; experimental part
p. 784 - 788
(2012/03/22)
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- Psoralenquinones as a novel class of proteasome inhibitors: Design, synthesis and biological evaluation
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Proteasome subunit specificity: Psoralenquinones were identified as a novel class of nonpeptide proteasome inhibitors. Depending on the scaffold decoration, these compounds demonstrate interesting subunit specificity. Interactions with Thr1, Thr21 and Ser129 are critical for inhibition.
- Marzaro, Giovanni,Gandin, Valentina,Marzano, Christine,Guiotto, Adriano,Chilin, Adriana
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scheme or table
p. 996 - 1000
(2012/01/06)
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- FUNCTIONALIZED PHENOLIC COMPOUNDS AND POLYMERS THEREFROM
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The present invention relates to compounds of formula I, which are functionalized phenolic compounds, and polymers formed from the same. Ar—[O—(X)p—R′]q??I Polymers formed from the functionalized phenolics are expected to have controllable degradation profiles, enabling them to release an active component over a desired time range. The polymers are also expected to be useful in a variety of medical applications.
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Page/Page column 23
(2009/07/17)
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- Alkoxypsoralens, novel nonpeptide blockers of Shaker-type K+ channels: Synthesis and photoreactivity
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A series of psoralens and structurally related 5,7-disubstituted coumarins was synthesized and investigated for their K+ channel blocking activity as well as for their phototoxicity to Artemia salina and their ability to generate singlet oxygen and to photomodify DNA. After screening the compounds on Ranvier nodes of the toad Xenopus laevis, the affinities of the most promising compounds, which proved to be psoralens bearing alkoxy substituents in the 5-position or alkoxymethyl substituents in the neighboring 4- or 4'-position, to a number of homomeric K+ channels were characterized. All compounds exhibited the highest affinity to Kv1.2. 5,8- Diethoxypsoralen (10d) was found to be an equally potent inhibitor of Kv1.2 and Kv1.3, while lacking the phototoxicity normally inherent in psoralens. The reported compounds represent a novel series of nonpeptide blockers of Shaker-type K+ channels that could be further developed into selective inhibitors of Kv1.2 or Kv1.3.
- Wulff, Heike,Rauer, Heiko,Düring, Tim,Hanselmann, Christine,Ruff, Katharina,Wrisch, Anja,Grissmer, Stephan,H?nsel, Wolfram
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p. 4542 - 4549
(2007/10/03)
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- SYNTHESIS OF FUROCOUMARIN DERIVATIVES LIKELY TO POSSESS ANTIMICROBIAL ACTIVITY
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The reaction of fuming nitric acid with bergapten (I) and xanthotoxin (II) afforded the corresponding nitro derivatives (IV and V respectively). With imperatorin (III) the reaction was found to be oxidation rather than nitration, and a nitrogen-free compound (VII) resulted. Molecular bromine reacted with bergapten (I) to afford three products (VIIIa - c) in a mixture, and with xanthotoxin (II) to produce the 5-bromo derivative (IX). Anomalously, molecular bromine reacted with imperatorin (III) to give the phenolic compound 5-bromo-9-hydroxy-furo(3,2-g)-coumarin (X). Structures of all products (VI - X) were confirmed by IR, 1H-NMR and mass spectral data.
- Kadry, H.,Osman, A. N.,Al-Azizi, M.,Ashour, M. S.
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p. 915 - 920
(2007/10/03)
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