- Catalytic transformation of 2,5-furandicarboxylic acid to adipic acid over niobic acid-supported Pt nanoparticles
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The conversion of biomass-derived molecules into adipic acid represents a highly attractive green route for sustainable production of adipic acid, a key monomer of nylon 66 and polyurethane. Here, we report the direct synthesis of adipic acid from 2,5-furandicarboxylic acid, which can be obtained from cellulose-based 5-hydroxymethylfurfural, using a niobic acid-supported platinum catalyst under hydrogen in water.
- Wei, Longfu,Zhang, Junxian,Deng, Weiping,Xie, Shunji,Zhang, Qinghong,Wang, Ye
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supporting information
p. 8013 - 8016
(2019/07/12)
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- Aerobic oxidation of C4-C6 α,ω-diols to the diacids in base-free medium over zirconia-supported (bi)metallic catalysts
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Oxidation of aliphatic α,ω-diols is a potentially interesting route to the production of valuable α,ω-diacids or ω-hydroxy acids for various polymer synthesis. 1,4-Butanediol (BDO), 1,5-pentanediol (PDO) and 1,6-hexanediol (HDO) are particularly attractive since they may be obtained from lignocellulosic biomass. The aqueous aerobic oxidation of these diols to the corresponding diacids was investigated in water over a set of Au, Pt, Au-Pt and Au-Pd catalysts supported on zirconia at 70 °C or 90 °C under 40 bar air. The nature of the metallic catalyst influenced the distribution of products as oxidation proceeded. The longer the carbon chain linking the terminal alcohol groups, the higher the yield of the diacid. The best yields of succinic acid, glutaric acid and adipic acid reached 83, 84 and 96% from BDO, PDO and HDO, respectively, over Au-Pt/ZrO2. There was some evidence of decarbonylation of the α,ω-hydroxyaldehyde at the early stage of the reaction. The presence of the hydroxyl substituent in 1,2,6-hexanetriol significantly slowed the oxidation rates compared with HDO. Besides, oxidation of PDO or HDO was highly selective to the ω-hydroxycarboxylate in moderate alkaline medium (NaOH/diol = 2) over Au/ZrO2 (90-93%).
- Mounguengui-Diallo, Modibo,Sadier, Achraf,Da Silva Perez, Denilson,Nikitine, Clémence,Puchot, Laura,Habibi, Youssef,Pinel, Catherine,Perret, Noémie,Besson, Michèle
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p. 9873 - 9885
(2019/07/04)
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- Acidic pH is a metabolic switch for 2-Hydroxyglutarate generation and signaling
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2-Hydroxyglutarate (2-HG) is an important epigenetic regulator, with potential roles in cancer and stem cell biology. The D-(R)-enantiomer (D-2-HG) is an oncometabolite generated from α-ketoglutarate (α-KG) by mutant isocitrate dehydrogenase, whereas L-(S)-2-HG is generated by lactate dehydrogenase and malate dehydrogenase in response to hypoxia. Because acidic pH is a common feature of hypoxia, as well as tumor and stem cell microenvironments, we hypothesized that pH may regulate cellular 2-HG levels. Herein we report that cytosolic acidification under normoxia moderately elevated 2-HG in cells, and boosting endogenous substrate α-KG levels further stimulated this elevation. Studies with isolated lactate dehydrogenase-1 and malate dehydrogenase-2 revealed that generation of 2-HG by both enzymes was stimulated severalfold at acidic pH, relative to normal physiologic pH. In addition, acidic pH was found to inhibit the activity of the mitochondrial L-2-HG removal enzyme L-2-HG dehydrogenase and to stimulate the reverse reaction of isocitrate dehydrogenase (carboxylation of α-KG to isocitrate). Furthermore, because acidic pH is known to stabilize hypoxia-inducible factor (HIF) and 2-HG is a known inhibitor of HIF prolyl hydroxylases, we hypothesized that 2-HG may be required for acid-induced HIF stabilization. Accordingly, cells stably overexpressing L-2-HG dehydrogenase exhibited a blunted HIF response to acid. Together, these results suggest that acidosis is an important and previously overlooked regulator of 2-HG accumulation and other oncometabolic events, with implications for HIF signaling.
- Sergiy, M. Nadtochiy,Xenia, Schafer,Dragony, Fu,Keith, Nehrke,Joshua, Munger,Brookes, Paul S.
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p. 20188 - 20197
(2016/11/03)
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- A paradigm for solvent and temperature induced conformational changes
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The complex conformational dependency on environment of Boc-amine (see scheme) has been investigated. This model organic molecule has many features applicable to areas of chemistry, biology, physics, and computational chemistry. It is soluble in both non-polar and polar solvents, conformationally heterogeneous, and capable of supramolecular assembly. Copyright
- Shpasser, Dina,Balazs, Yael S.,Kapon, Moshe,Sheynis, Tania,Jelienk, Raz,Eisen, Moris S.
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supporting information; experimental part
p. 8285 - 8289
(2011/08/07)
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- METHOD FOR SYNTHESIS OF KETO ACID OR AMINO ACID BY HYDRATION OF ACETHYLENE COMPOUND
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An object of the present invention is to provide a method for synthesis of keto acids by hydration of an acetylene compound (acetylene-carboxylic acids) under mild conditions free from harmful mercury catalysts and a method for synthesis of amino acids from acetylene-carboxylic acids in a single container (one-pot or tandem synthesis). In one embodiment of the method according to the present invention for synthesis of keto acids, acetylene-carboxylic acids is hydrated in the presence of a metal salt represented by General Formula (1), where M1 represents an element in Group VIII, IX, or X of the periodic table, and X1, X2, or X3 ligand represents halogen, H2O, or a solvent molecule, and k represents a valence of a cation species, and Y represents an anion species, and L represents a valence of the anion species, and each of K and L independently represents 1 or 2, and k × m = L × n.
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Page/Page column 24
(2008/12/06)
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- Cosmetic compositions for reducing or preventing signs of cellulite
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The invention is directed to increasing the strength and firmness of the skin and reducing the signs of cellulite. The inventive method includes applying to the skin a composition that includes inositol phosphate, particularly phytic acid and its salts, in a cosmetically acceptable carrier.
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