- Synthesis and X-ray Characterization of Alkali Metal 2-Acyl-1,1,3,3-tetracyanopropenides
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A novel route for synthesis of 2-acyl-1,1,3,3-tetracyanopropenides (ATCN) salts in high yields and excellent purities starting from readily available methyl ketones, malononitrile, bromine, and alkali metal acetates is reported. The starting aryl(heteroaryl) methyl ketones were oxidized to the corresponding α-ketoaldehydes by new a DMSO-NaBr-H2SO4 oxidation system in yields up to 90% within a short reaction time of 8-10 min. The subsequent stages of ATCN preparation are realized in aqueous media without use of any toxic solvents, in accordance with principle 5 of "green chemistry". Lithium, sodium, potassium, rubidium, and cesium 2-benzoyl-1,1,3,3-tetracyanopropenides were characterized by X-ray diffraction analysis. These salts show a good potential for synthesis of five- and six-membered heterocycles and may serve as potentially useful ligands in coordination and supramolecular chemistry.
- Karpov, Sergey V.,Grigor'Ev, Arthur A.,Kayukov, Yakov S.,Karpova, Irina V.,Nasakin, Oleg E.,Tafeenko, Victor A.
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p. 6402 - 6408
(2016/08/16)
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- Keto-Enol Thermodynamics of Breslow Intermediates
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Breslow intermediates, first postulated in 1958, are pivotal intermediates in carbene-catalyzed umpolung. Attempts to isolate and characterize these fleeting amino enol species first met with success in 2012 when we found that saturated bis-Dipp/Mes imida
- Paul, Mathias,Breugst, Martin,Neud?rfl, J?rg-Martin,Sunoj, Raghavan B.,Berkessel, Albrecht
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supporting information
p. 5044 - 5051
(2016/05/19)
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- Integration of chemical and biological catalysis: Production of furylglycolic acid from glucose via cortalcerone
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Furylglycolic acid (FA), a pseudoaromatic hydroxy-acid suitable for copolymerization with lactic acid, can be produced from glucose via enzymatically derived cortalcerone using a combination of Bronsted and Lewis acid catalysts. Cortalcerone is first converted to furylglyoxal hydrate (FH) over a Bronsted acid site (HCl or Al-containing beta-zeolite), and FH is subsequently converted to FA over a Lewis acid site (Sn-beta zeolite). Selectivity for conversion of FH to FA is as high as 80% at 12% conversion using tetrahydrofuran (THF) as a solvent at 358 K. Higher conversion of FH leads to FA-catalyzed degradation of FH and subsequent deactivation of the catalyst by the deposition of carbonaceous residues. The deactivated catalyst can be regenerated by calcination. Cortalcerone can be produced from 10% glucose solution using recombinant Escherichia coli strains expressing pyranose 2-oxidase and aldos-2-ulose dehydratase from the wood-decay fungus Phanerochaete chrysosporium BKM-F-1767. This enzymatically derived cortalcerone is converted in one pot to FA in a methanol/water solvent over an Al-containing Sn-beta zeolite possessing both Bronsted and Lewis acid sites, achieving 42% selectivity to FA at 53% cortalcerone conversion.
- Schwartz, Thomas J.,Goodman, Samuel M.,Osmundsen, Christian M.,Taarning, Esben,Mozuch, Michael D.,Gaskell, Jill,Cullen, Daniel,Kersten, Philip J.,Dumesic, James A.
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p. 2689 - 2693
(2014/01/06)
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- Metal-free dual sp3 C-H functionalization: I2- promoted domino oxidative cyclization to construct 2,5-disubstituted oxazoles
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An I2-promoted sp3 C-H functionalization has been developed for the synthesis of 2,5-disubstituted oxazoles from easily available methyl ketones and benzylamines without any metal and peroxide catalyst. This domino oxidative cyclization process involves the cleavage of C-H bond and the formation of C-N, C-O bonds.
- Gao, Qing-He,Fei, Zhuan,Zhu, Yan-Ping,Lian, Mi,Jia, Feng-Cheng,Liu, Mei-Cai,She, Neng-Fang,Wu, An-Xin
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- Oxidation of diazo compounds by dimethyl dioxirane: An extremely mild and efficient method for the preparation of labile α-oxo-aldehydes
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A novel method for the preparation of α-oxo-aldehydes by dimethyl dioxirane oxidation of α-diazoketones is described. The procedure is particularly useful when the desired compound cannot be purified by chromatography or distillation: the by-products (ace
- Ihmels,Maggini,Prato,Scorrano
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p. 6215 - 6218
(2007/10/02)
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