- Cyanide as a primordial reductant enables a protometabolic reductive glyoxylate pathway
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Investigation of prebiotic metabolic pathways is predominantly based on abiotically replicating the reductive citric acid cycle. While attractive from a parsimony point of view, attempts using metal/mineral-mediated reductions have produced complex mixtures with inefficient and uncontrolled reactions. Here we show that cyanide acts as a mild and efficient reducing agent mediating abiotic transformations of tricarboxylic acid intermediates and derivatives. The hydrolysis of the cyanide adducts followed by their decarboxylation enables the reduction of oxaloacetate to malate and of fumarate to succinate, whereas pyruvate and α-ketoglutarate themselves are not reduced. In the presence of glyoxylate, malonate and malononitrile, alternative pathways emerge that bypass the challenging reductive carboxylation steps to produce metabolic intermediates and compounds found in meteorites. These results suggest a simpler prebiotic forerunner of today’s metabolism, involving a reductive glyoxylate pathway without oxaloacetate and α-ketoglutarate—implying that the extant metabolic reductive carboxylation chemistries are an evolutionary invention mediated by complex metalloproteins. [Figure not available: see fulltext.].
- Krishnamurthy, Ramanarayanan,Pulletikurti, Sunil,Yadav, Mahipal,Yerabolu, Jayasudhan R.
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p. 170 - 178
(2022/02/11)
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- Method for preparing hydroxy dibasic acid by catalyzing oxidation of acetyl acid raw material
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The invention provides a method for preparing hydroxy dibasic acid by catalyzing oxidation of an acetyl acid raw material. A two-component catalytic system is adopted. One or more than two of metal or metal oxides in transition metal ruthenium, palladium, platinum, gold, silver, nickel, cobalt, copper, molybdenum, iron, rhodium and iridium form a first catalytic component. One or more than two of an alkaline compound of calcium and an alkaline compound of strontium form a second catalytic component. According to the method, an acetyl acid compound is used as a reaction raw material and is subjected to a one-step catalytic oxidation process under the hydrothermal conditions that the temperature is 50-170 DEG C and the oxygen pressure is greater than 0.1 MPa, so that the hydroxyl dibasic acid is prepared from the acetyl acid compound with high efficiency, high selectivity and high yield. Compared with the existing hydroxyl dibasic acid synthesis route, the method provided by the invention has the remarkable advantages of mild reaction conditions, environmental friendliness, high oxidation efficiency, easiness in recovery of the heterogeneous catalyst, good practicability, good application prospect and the like.
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Paragraph 0028-0084
(2021/06/09)
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- Catalytic Aerobic Oxidation of Lignocellulose-Derived Levulinic Acid in Aqueous Solution: A Novel Route to Synthesize Dicarboxylic Acids for Bio-Based Polymers
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The world is facing grand and ever-increasing pressures on energy and environmental issues. Using carbon-neutral biomass to prepare monomers such as dicarboxylic acids for degradable polymers is of great significance and an urgent but challenging task. Herein, we report a catalytic route for the synthesis of 2-hydroxy-2-methylsuccinic acid, an excellent monomer: e.g., it is able to remarkably enhance the comprehensive properties of polybutylene succinate as shown herein. By catalytic aerobic oxidation of levulinic acid, a bulk platform chemical derived from lignocellulose, the target product was obtained with a very high selectivity of up to ca. 95%. The mild reaction conditions below 100 °C in water and the low-cost reusable heterogeneous catalyst further make the process highly attractive for applications. This process was also found to be effective for the conversion of homologues of levulinic acid to dicarboxylic acids. We studied the C-C bond rearrangement and the roles of catalysts in the reaction that are highly likely involved in a superoxide anion radical mechanism. This study may provide inspiration for the synthesis of bio-based dicarboxylic acids via alternative routes.
- Che, Li,Jiang, Min,Jiang, Yu,Pang, Jifeng,Song, Lei,Wang, Rui,Zhang, Tao,Zhao, Yu,Zheng, Mingyuan,Zhou, Guangyuan,Zhou, Mo
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p. 11588 - 11596
(2021/09/22)
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- Anchimeric-Assisted Spontaneous Hydrolysis of Cyanohydrins Under Ambient Conditions: Implications for Cyanide-Initiated Selective Transformations
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Nitrile/cyanide hydrolysis is of importance from the perspective of organic chemistry, especially, prebiotic chemistry. Herein we report that cyanohydrins, generated by the reaction of cyanide with β-keto acids and γ-keto-alcohols, spontaneously hydrolyze
- Yerabolu, Jayasudhan Reddy,Liotta, Charles L,Krishnamurthy, Ramanarayanan
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supporting information
p. 8756 - 8765
(2017/06/30)
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- Chemical compositions of secondary organic aerosol from the ozonolysis of cyclohexene in the absence of seed particles
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The composition of the aerosol from the ozonolysis of cyclohexene in the absence of seed particles has been investigated by laboratory chamber experiments. The aerosol collected on filters was analyzed by a liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry. Low-molecular weight products, i.e., dicarboxylic acids, oxocarboxylic acids, and hydroxydicarboxylic acids, as well as oligomers with molecular weights more than 200 were found in the aerosol. Copyright
- Sato, Kei
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p. 1584 - 1585
(2007/10/03)
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- Oxidation of Creosol with Oxygen in Alkaline Aqueous Solution. Model Experiments on Oxygen Pulping of Wood
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Reaction of creosol (2-methoxy-4-methyl-phenol) with oxygen in alkaline aqueous solution gave several neutral and acidic compounds which were identified.By quantitative determination of the degradation products an evaluation of the degradation pathways was possible. - Keywords: Cyclohexadienons as intermediates; Oxygen bleaching; Oxygen pulping; Phenol oxidation; Gas chromatography of methyl esters
- Fricko, Paul,Holocher-Ertl, Martin,Kratzl, Karl
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p. 1025 - 1042
(2007/10/02)
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- Reaction of Dinitrogen Tetraoxide with Hydrophilic Olefins: Synthesis of Citric and 2-Hydroxy-2-methylbutanedioic Acids
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Liquid olefins typically react with N2O4 by free-radical reactions to form dinitro and nitronitrite derivatives.Introduction of hydrophilic substituents into 1-olefins altered the course of the reaction of the olefins with N2O4 in aqueous HNO3.Citric acid was formed in 64 mol percent yield by the reaction of 3-methylene-1,5-pentanediol with N2O4 in aqueous HNO3.Similarly, 2-hydroxy-2-methylbutanedioic acid was made from 3-methyl-3-buten-1-ol in 88percent yield.These results are explained by solution of the hydrophilic olefins in aqueous HNO3-N2O4 and addition of N2O4 to the double bond as NO+ and NO3- ions to yield nitrosonitrates, which react further to give the final products.
- Wilkes, John B.,Wall, Robert G.
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p. 247 - 250
(2007/10/02)
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