- Synthesis and evaluation of arylquinones as BACE1 inhibitors, β-amyloid peptide aggregation inhibitors, and destabilizers of preformed β-amyloid fibrils
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BACE1 activity, inhibition of Aβ aggregation, and disaggregation of preformed Aβ fibrils constitute the three major targets in the development of small-molecule lipophilic new drugs for the treatment of Alzheimer's disease (AD). Quinones are widely distributed among natural products and possess relevant and varied biological activities including antitumor and antibiotic, inhibition of HIV-1 reverse transcriptase, antidiabetic, or COX-inhibition, among others. We report herein the interaction of several arylquinones and their derivatives with the amyloidogenic pathway of the amyloid precursor protein processing. Our studies put forward that these compounds are promising candidates in the development of new drugs which are effective simultaneously towards the three major targets of AD.
- Ortega, Andrea,Rincón, ángela,Jiménez-Aliaga, Karim L.,Bermejo-Bescós, Paloma,Martín-Aragón, Sagrario,Molina, María Teresa,Csák?, Aurelio G.
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- Studies on the Meerwein Arylation-Based Preparation of 2,3-Diarylbenzene-1,4-diones and Its Theoretical Interpretation
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Title compounds possessing a variety of substituents are systematically prepared by means of Meerwein arylation of benzene-1,4-dione. Synthetic aspects and their MNDO calculation-based interpretation are described.
- Takahashi, Ichiro,Muramatsu, Osamu,Fukuhara, Jun,Hosokawa, Yoshinao,Takeyama, Naohiko,et al.
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- Ruthenium(II) Porphyrin Quinoid Carbene Complexes: Synthesis, Crystal Structure, and Reactivity toward Carbene Transfer and Hydrogen Atom Transfer Reactions
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Reactivity study of novel metal carbene complexes can offer new opportunities in catalytic carbene transfer reactions as well as in other synthetic protocols. Metal complexes with quinoid carbene (QC) ligands are assumed to be key intermediates in a variety of metal-catalyzed QC transfer reactions using diazo quinones, which demands development of the chemistry of QC transfer of well characterized metal-QC complexes. Herein we report the isolation and QC transfer of ruthenium porphyrins [Ru(Por)(QC)] which contribute the first examples of (i) structurally characterized metal-QC complex (by X-ray crystallography) and (ii) isolated metal-QC complex that undergoes QC transfer reaction. The complexes [Ru(Por)(QC)] were prepared from reaction of [Ru(Por)(CO)] with diazo quinones and exhibited dual reactivity, i.e., hydrogen atom transfer (HAT) as well as QC transfer. The stoichiometric QC transfer reactions from these Ru-QC complexes to nitrosoarenes (ArNO) afforded nitrones in up to 90% yield, and the corresponding catalytic reactions were also developed. Both the stoichiometric and catalytic reactions for a series of QC ligands bearing electron-donating and -withdrawing substituents showed a reverse substituent effect on the QC transfer reactivity. Complexes [Ru(Por)(QC)] are also reactive toward C-H and X-H (X = N, S) bonds and can catalyze aerobic oxidation of 1,4-cyclohexadiene; their stoichiometric HAT reactions with unsaturated hydrocarbons gave product yields of up to 88%. The unique dual reactivity and electronic feature of [Ru(Por)(QC)] were studied by spectroscopic means and density functional theory (DFT) calculations.
- Wang, Hai-Xu,Wan, Qingyun,Wu, Kai,Low, Kam-Hung,Yang, Chen,Zhou, Cong-Ying,Huang, Jie-Sheng,Che, Chi-Ming
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supporting information
p. 9027 - 9046
(2019/06/13)
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- Palladium-catalyzed direct C-H functionalization of benzoquinone
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A direct Pd-catalyzed C-H functionalization of benzoquinone (BQ) can be controlled to give either mono- or disubstituted BQ, including the installation of two different groups in a one-pot procedure. BQ can now be directly functionalized with aryl, heteroaryl, cycloalkyl, and cyclo-alkene groups and, moreover, the reaction is conducted in environmentally benign water or acetone as solvents.
- Walker, Sarah E.,Jordan-Hore, James A.,Johnson, David G.,MacGregor, Stuart A.,Lee, Ai-Lan
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supporting information
p. 13876 - 13879
(2015/02/05)
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- Tandem oxidation-oxidative C-H/C-H cross-coupling: Synthesis of arylquinones from hydroquinones
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A concise and efficient approach to arylquinones from widely available hydroquinones has been developed through a tandem reaction involving the oxidation of hydroquinones and subsequent oxidative C-H/C-H cross-coupling of the resulting quinones with arenes.
- Zhang, Shuai,Song, Feijie,Zhao, Dongbing,You, Jingsong
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supporting information
p. 4558 - 4560
(2013/06/04)
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- Degradation of the adsorbent tenax TA by nitrogen oxides, ozone, hydrogen peroxide, OH radical, and limonene oxidation products
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The degradation of the adsorbent Tenax TA was studied qualitatively by sampling oxidants common in indoor air followed by thermal desorption and gas chromatography. A total of 25 degradation products were identified. Several degradation products not reported previously were identified: 9 for nitrogen dioxide; 11 for ozone; 2 for hydrogen peroxide; 12 for hydroxyl radical; 1 for ozonelimonene mixtures, but none for nitrogen oxide. Whereas ozone shows a complex degradation of the adsorbent, hydrogen peroxide and limonene-ozone mixtures show few products. Nitrogen dioxide and the hydroxyl radical behave almost identically and produce 2,6-diphenyl-p-benzoquinone as the major degradation product. Reactant specific degradation products were identified for ozone (11) and nitrogen dioxide (1).
- Kleno, Jacob G.,Wolkoff, Peder,Clausen, Per A.,Wilkins, Cornelius K.,Pedersen, Thorvald
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p. 4121 - 4126
(2007/10/03)
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- Arylation of quinones with aryl mercuryl chloride catalyzed by lithium palladium chloride
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Treatment of benzoquinone/naphthoquinone with aryl mercury chloride in the presence of palladium chloride and lithium chloride gives the corresponding aryl substituted benzoquinone/naphthoquinone at the quinonoid position.
- Singh,Rohtagi,Khanna
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p. 987 - 993
(2007/10/02)
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- Oxidative Coupling of Quinones and Aromatic Compounds by Palladium(II) Acetate
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The oxidation of 1,4-benzoquinone, 2-phenyl-1,4-benzoquinone, 1,4-naphthoquinone, and 1,2-naphthoquinone by palladium(II) acetate in acetic acid containing arenes gave the corresponding aryl-sustituted quinones.Treatment of 1,4-naphthoquinone with aromatic heterocycles such as furfural, 2-acetylfuran, methyl 2-furoate, 2-acetylthiophene, 1-(phenylsulfonyl)pyrrole, 1-(phenylsulfonyl)indole, 4-pyrone, and 1-methyl-2-pyridone in the presence of palladium acetate gave the corresponding 2-heteroaryl-substituted 1,4-naphthoquinones.
- Itahara, Toshio
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p. 5546 - 5550
(2007/10/02)
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- Arylation of Quinones with Arenes and Palladium Acetate
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Oxidation of quinones with palladium acetate in acetic acid, which contained arenes, gave arylated quinones.
- Itahara, Toshio
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p. 859 - 860
(2007/10/02)
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- Nitrations and Oxidations with Inorganic Nitrate Salts in Trifluoroacetic Anhydride
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Metal nitrates in trifluoroacetic anhydride nitrate many aromatic compounds in high yields at room temperature, including polymers with aromatic groups.However, this system oxidizes phenols to quinoid products.
- Crivello, J.V.
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p. 3056 - 3060
(2007/10/02)
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