- Sol-gel synthesis of ceria-zirconia-based high-entropy oxides as high-promotion catalysts for the synthesis of 1,2-diketones from aldehyde
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Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.
- Dinjar, Kristijan,Djerdj, Igor,Koj?inovi?, Jelena,Kukovecz, ákos,Markovi?, Berislav,Mileti?, Aleksandar,Nagy, Sándor Balázs,Sapi, Andras,Stenzel, David,Széchenyi, Aleksandar,Szenti, Imre,Tang, Yushu,Tatar, Dalibor,Varga, Gábor,Ziegenheim, Szilveszter
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- (±)Methanodibenzodiazocine tethered [C-H]δ+ functional site: Study towards benzoin condensation and Baylis-Hillman reactions
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Abstract New heterocyclic ring systems consisting of (±) methanodibenzodiazocine and imidazolium/ benzimidazolium salts were synthesized in very good yield. Subsequently, these halide salts were subjected to the anion exchange reaction with KPF6 to yield the corresponding azolium salts in excellent yield. The possible applications of these newly prepared salts were investigated in homogeneous catalysis. Remarkable changes in the catalytic activity were observed by varying the bulkiness of N-substituent at imidazole. Catalytic activity of these newly prepared salts was tested for the benzoin condensation reaction. Exclusive formation of benzoin products were observed in good yield. Similarly, the dimerization of cyclohexen-1-one to Baylis-Hillman type product, 2-(3-oxocyclohexyl)-2-cyclohexen-1-one was studied. [Figure not available: see fulltext.]
- Sathyanarayana, Arruri,Prabusankar, Ganesan
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p. 821 - 831
(2015/08/06)
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- Unexpected transformation of aldehydes into benzoins with Copper(I)/Samarium
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The reductive coupling of aldehydes to afford pinacolic alcohols using all kinds of reducing agents involving samarium is well known. In this report, however, treatment of aromatic aldehydes with Cu(I)/Sm system produces benoins and/or benzils in good yields. A possible mechanism is proposed where Cu(I) not only activates the Sm metal but also promotes the dehydrogenation of the intermediates, during which a Cu(III) species may be involved. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Liu, Yongjun,Wang, Hui,Fu, Yulong,Qi, Yan,Yang, Kuiwei
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p. 259 - 266
(2013/12/04)
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- Synthesis and evaluation of quinoxaline derivatives as potential influenza NS1A protein inhibitors
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A library of quinoxaline derivatives were prepared to target non-structural protein 1 of influenza A (NS1A) as a means to develop anti-influenza drug leads. An in vitro fluorescence polarization assay demonstrated that these compounds disrupted the dsRNA-NS1A interaction to varying extents. Changes of substituent at positions 2, 3 and 6 on the quinoxaline ring led to variance in responses. The most active compounds (35 and 44) had IC50 values in the range of low micromolar concentration without exhibiting significant dsRNA intercalation. Compound 44 was able to inhibit influenza A/Udorn/72 virus growth.
- You, Lei,Cho, Eun Jeong,Leavitt, John,Ma, Li-Chung,Montelione, Gaetano T.,Anslyn, Eric V.,Krug, Robert M.,Ellington, Andrew,Robertus, Jon D.
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scheme or table
p. 3007 - 3011
(2011/06/24)
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- COMPOUNDS, COMPOSITIONS AND METHODS FOR THE TREATMENT OF AMYLOID DISEASES AND SYNUCLEINOPATHIES SUCH AS ALZHEIMER'S DISEASE, TYPE 2 DIABETES, AND PARKINSON'S DISEASE
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Bis- and tris-dihydroxyaryl compounds and their methylenedioxy analogs and pharmaceutically acceptable esters, their synthesis, pharmaceutical compositions containing them, and their use in the treatment of amyloid diseases, especially A? amyloidosis, such as observed in Alzheimer's disease, IAPP amyloidosis, such as observed in type 2 diabetes, and synucleinophathies, such as observed in Parkinson's disease, and the manufacture of medicaments for such treatment.
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- Catalytic action of azolium salts. VI. Preparation of benzoins and acyloins by condensation of aldehydes catalyzed by azolium salts
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Benzoins 4 (2-hydroxyethanones substituted with aryl groups at the 1- and 2-positions) were prepared by self-condensation of aromatic aldehydes 3 using catalytic amounts of azolium salts 1 and 2 in excellent yields. 1,3-Dimethylbenzimidazolium iodide (2) was an effective catalyst for the preparation of acyloins 6 (2-hydroxyethanones substituted with alkyl groups at the 1- and 2-positions) by self-condensation of aliphatic aldehydes 5. On the other hand, an attempt at the condensation of hexanal (5d) catalyzed by 1,3-dimethylimidazolium iodide (1) failed to yield the acyloin 6d, and instead the aldol-type condensed product 8d was obtained.
- Miyashita,Suzuki,Iwamoto,Higashino
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p. 2633 - 2635
(2007/10/02)
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- CYANOHYDRINS AS SUBSTRATES IN BENZOIN CONDENSATION. REGIOCONTROLLED MIXED BENZOIN CONDENSATION
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O-Benzoylated cyanohydrins of aromatic aldehydes have been used as one of the substrates in the benzoin condensation.They were treated with aromatic aldehydes under phase-transfer conditions to result in benzoin benzoates.By this method aldehydes which fail to undergo condensation using traditional conditions could be converted into benzoins.By the Umpolung of reactivity of the pertinent aldehyde it was possible to prepare both isomeric unsymmetrical benzoins, including the thermodynamically less stable ones.
- Rozwadowska, Maria D.
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p. 3135 - 3140
(2007/10/02)
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