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ketones aerobic

Zhen Yin, Yumei Zheng, Hong Wang, Jianxin Li, Qingjun Zhu, Ye Wang, Na Ma, Gang Hu, Benqiao He, Axel Knop-Gericke, Robert Schloegl, Ding Ma
Electrochemical oxidation has attracted vast interests as a promising alternative to traditional chemical processes in fine chemical synthesis owing to its fast and sustainable features. An electrocatalytic membrane reactor (ECMR) with a three-dimensional (3D) electrode has been successfully designed for the selective oxidation of alcohols with high current efficiency to the corresponding acids or ketones. The anode electrode was fabricated by the in-situ loading of one-dimensional (1D) Co3O4 nanowires (NWs) on the conductive porous Ti membrane (Co3O4 NWs/Ti) via the combination of a facile hydrothermal synthesis and subsequent thermal treatment...
November 15, 2017: ACS Nano
Pedro Almendros, Benito Alcaide, Israel Fernández, Fernando Herrera, Amparo Luna
An unprecedented metal-free direct preparation of unprotected α-hydroxy ketones from terminal alkynes under mild conditions with diazonium salts as the arene source and without the requirement of irradiation is described. The process is general and fully compatible with a wide variety of substitution in both reactants. Experimental and computational evidences strongly suggest the involvement of radical species in the transformation.
November 2, 2017: Chemistry: a European Journal
Miquel Navarro, Christene A Smith, Martin Albrecht
A set of aryl-substituted pyridylideneamide (PYA) ligands with variable donor properties owing to a pronounced zwitterionic and a neutral diene-type resonance structure were used as electronically flexible ligands at a pentamethylcyclopentadienyl (Cp*) iridium center. The straightforward synthesis of this type of ligand allows for an easy incorporation of donor substituents such as methoxy groups in different positions of the phenyl ring of the C,N-bidentate chelating PYA. These modifications considerably enhance the catalytic activity of the coordinated iridium center toward the catalytic aerobic transfer hydrogenation of carbonyls and imines as well as the hydrosilylation of phenylacetylene...
October 2, 2017: Inorganic Chemistry
Masaki Takahashi, Hiromu Koizumi, Wang-Jae Chun, Makoto Kori, Takane Imaoka, Kimihisa Yamamoto
The catalytic activity of alloy nanoparticles depends on the particle size and composition ratio of different metals. Alloy nanoparticles composed of Pd, Pt, and Au are widely used as catalysts for oxidation reactions. The catalytic activities of Pt and Au nanoparticles in oxidation reactions are known to increase as the particle size decreases and to increase on the metal-metal interface of alloy nanoparticles. Therefore, multimetallic nanoclusters (MNCs) around 1 nm in diameter have potential as catalysts for oxidation reactions...
July 2017: Science Advances
Yu-Feng Liang, Ning Jiao
The selective oxidation of organic molecules is a fundamentally important component of modern synthetic chemistry. In the past decades, direct oxidative C-H and C-C bond functionalization has proved to be one of the most efficient and straightforward methods to synthesize complex products from simple and readily available starting materials. Among these oxidative processes, the use of molecular oxygen as a green and sustainable oxidant has attracted considerable attention because of its highly atom-economical, abundant, and environmentally friendly characteristics...
June 21, 2017: Accounts of Chemical Research
Vincent Escande, Chun Ho Lam, Philip Coish, Paul T Anastas
The aerobic oxidative cleavage of 1,2-diols using a heterogeneous catalyst only based on earth-abundant metals manganese and sodium is reported for the first time. This reusable catalyst cleaves a variety of substrates into aldehydes or ketones with high selectivity. The reaction requires small catalytic loadings and is performed under mild conditions using ambient pressure O2 or air as the oxidant while producing water as the only by-product. Mechanistic investigations reveal a monodentate, two-electron oxidative fragmentation process involving a Mn(IV) species...
August 1, 2017: Angewandte Chemie
Gábor Zoltán Elek, Victor Borovkov, Margus Lopp, Dzmitry G Kananovich
An efficient, mild, and environmentally benign method was developed for the asymmetric synthesis of 2-oxyranyl ketones from easily available tertiary cyclopropanols. The one-pot protocol includes the aerobic oxidation of cyclopropanol derivatives catalyzed by Mn(III) complexes followed by the poly-l-leucine-assisted stereoselective elimination of water from the intermediate peroxides with DBU to afford the corresponding epoxy ketones in high yields and good-to-excellent enantioselectivities (up to 97%).
June 13, 2017: Organic Letters
Tzuen-Yang Ye, Manikandan Selvaraju, Chung-Ming Sun
A three-component cascade reaction of 2-aminobenzimidazole, aldehyde, and terminal alkyne has been explored for an efficient synthesis of benzimidazole-linked tetrasubstituted pyrroles. The reaction sequence involves the formation of propargylamine, insertion of a terminal alkyne, and a ring opening reaction followed by an intramolecular carbonylative cyclization under aerobic conditions. It represents a novel strategy to the construction of C═N, C═C, C═O bonds and a new five-membered 2-ketopyrrole ring...
June 5, 2017: Organic Letters
Le Shi, Daina Zhao, Chen Hou, Yunhua Peng, Jing Liu, Shuangxi Zhang, Jiankang Liu, Jiangang Long
Alzheimer's disease (AD) is considered a multifactorial disease that affects the central nervous system and periphery. A decline in brain glucose metabolism is an early feature of AD and is accompanied by a phenotypic shift from aerobic glycolysis to ketogenesis. The liver is responsible for the generation of the ketone body. However, the mechanism that underlies hepatic ketogenesis in AD remains unclear. Here, we investigated hepatic ketogenesis during the early stage of AD pathogenesis in amyloid precursor protein (APPSWE) and presenilin (PSEN1dE9) (APP/PS1) mice...
April 26, 2017: Neurobiology of Aging
Katsuhiko Moriyama, Tsukasa Hamada, Yu Nakamura, Hideo Togo
Catalytic dehydrogenative dual functionalization (DDF) of ethers via oxidation, dealkylation, and α-bromination by the aerobic oxidation of bromide was developed to obtain the corresponding α-bromo ketones in high yields. In particular, the reaction of substituted tetrahydrofurans as cyclic ethers provided 3,3-dibromo tetrahydrofuran-2-ols in high yields selectively through the double α-bromination.
June 16, 2017: Chemical Communications: Chem Comm
Damian P Hruszkewycz, Kelsey C Miles, Oliver R Thiel, Shannon S Stahl
A simple cobalt(ii)/N-hydroxyphthalimide catalyst system has been identified for selective conversion of benzylic methylene groups in pharmaceutically relevant (hetero)arenes to the corresponding (hetero)aryl ketones. The radical reaction pathway tolerates electronically diverse benzylic C-H bonds, contrasting recent oxygenation reactions that are initiated by deprotonation of a benzylic C-H bond. The reactions proceed under practical reaction conditions (1 M substrate in BuOAc or EtOAc solvent, 12 h, 90-100 °C), and they tolerate common heterocycles, such as pyridines and imidazoles...
February 1, 2017: Chemical Science
Arianna Roda, Luigi Lucini, Fabrizio Torchio, Roberta Dordoni, Dante Marco De Faveri, Milena Lambri
Vinegar is an inexpensive commodity, and economic considerations require that a relatively low-cost raw material be used for its production. An investigation into the use of a new, alternative substrate - pineapple waste - is described. This approach enables the utilization of the pineapple's (Ananas comosus) peels and core, which are usually discarded during the processing or consumption of the fruit. Using physical and enzymatic treatments, the waste was saccharified, and the resulting substrate was fermented with Saccharomyces cerevisiae for 7-10days under aerobic conditions at 25°C...
August 15, 2017: Food Chemistry
Keisuke Ueda, Chiaki Sanbongi, Shoko Takai, Shuji Ikegami, Satoshi Fujita
During exercise, blood levels of several hormones increase acutely. We hypothesized that consumption of a specific combination of amino acids (arginine, alanine, and phenylalanine; A-mix) may be involved in secretion of glucagon, and when combined with exercise may promote fat catabolism. Ten healthy male volunteers were randomized in a crossover study to ingest either A-mix (3 g/dose) or placebo (3 g of dextrin/dose). Thirty minutes after ingesting, each condition subsequently performed workload trials on a cycle ergometer at 50% of maximal oxygen consumption for 1 h...
July 2017: Bioscience, Biotechnology, and Biochemistry
Daniela A Rubin, Susan J Clark, Andrea M Haqq, Diobel M Castner, Jason Ng, Daniel A Judelson
BACKGROUND: Prader-Willi syndrome (PWS) is characterized by excessive adiposity. Excess adiposity negatively affects hormonal and metabolic responses to aerobic exercise. This study determined whether PWS and/or adiposity affected hormonal and metabolic responses to resistance exercise. METHODS: Eleven children with PWS (11.4 ± 3.1 years, 43.9 ± 7.5% body fat), 12 lean children (9.3 ± 1.4 years, 18.3 ± 4.9% body fat), and 13 obese children (9.6 ± 1.3 years, 40...
2017: Hormone Research in Pædiatrics
Paul Urbain, Lena Strom, Lena Morawski, Anja Wehrle, Peter Deibert, Hartmut Bertz
BACKGROUND: The ketogenic diet (KD) is a very low-carbohydrate, high-fat and adequate-protein diet that without limiting calories induces different metabolic adaptations, eg, increased levels of circulating ketone bodies and a shift to lipid metabolism. Our objective was to assess the impact of a 6-week non-energy-restricted KD in healthy adults beyond cohorts of athletes on physical performance, body composition, and blood parameters. METHODS: Our single arm, before-and-after comparison study consisted of a 6-week KD with a previous preparation period including detailed instructions during classes and individual counselling by a dietitian...
2017: Nutrition & Metabolism
Peng-Yi Ji, Yu-Feng Liu, Jing-Wen Xu, Wei-Ping Luo, Qiang Liu, Can-Cheng Guo
A novel K2S2O8-promoted decarboxylative cross coupling of α,β-unsaturated carboxylic acids with cyclic ethers was developed under aerobic conditions. The present protocol, which includes C-C and C═O bond formation in one step through addition, oxidation, and decarboxylation processes, leads to the desired ketone products in moderate to excellent yields. In addition, mechanism studies showed that the transformation process undergoes a radical pathway via a direct activation of the α-sp(3) C-H bond of oxygen of the cyclic ether...
February 28, 2017: Journal of Organic Chemistry
Wenhui Wang, Junwen Han, Jinwei Sun, Yun Liu
An efficient synthesis of diversified indolizine derivatives was developed via CuBr-catalyzed reaction of pyridines, methyl ketones and alkenoic acids under solvent-free conditions in oxygen atmosphere. This synthesis involves cascade processes of copper-catalyzed bromination of the methyl ketone, 1,3-dipolar cycloaddition of the pyridinium ylide with the alkenoic acid, followed by oxidative decarboxylation and dehydrogenative aromatization of the primary cycloadduct. By this protocol, a wide range of indoliznes with different substitution patterns were selectively prepared in one pot from simple substrates in good to excellent yields...
February 28, 2017: Journal of Organic Chemistry
Arunachalam Sagadevan, Vaibhav Pramod Charpe, Ayyakkannu Ragupathi, Kuo Chu Hwang
Direct oxidative coupling of phenols and terminal alkynes was achieved at room temperature by a visible-light-mediated copper-catalyzed photoredox process. This method allows regioselective synthesis of hydroxyl-functionalized aryl and alkyl ketones from simple phenols and phenylacetylene via C≡C triple bond cleavage. 47 examples were presented. From a synthetic perspective, this protocol offers an efficient synthetic route for the preparation of pharmaceutical drugs, such as pitofenone and fenofibrate.
February 15, 2017: Journal of the American Chemical Society
Christian-Alexandre Castellano, Nancy Paquet, Isabelle J Dionne, Hélène Imbeault, Francis Langlois, Etienne Croteau, Sébastien Tremblay, Mélanie Fortier, J Jacques Matte, Guy Lacombe, Tamás Fülöp, Christian Bocti, Stephen C Cunnane
BACKGROUND: Aerobic training has some benefits for delaying the onset or progression of Alzheimer's disease (AD). Little is known about the implication of the brain's two main fuels, glucose and ketones (acetoacetate), associated with thesebenefits. OBJECTIVE: To determine whether aerobic exercise training modifies brain energy metabolism in mild AD. METHODS: In this uncontrolled study, ten patients with mild AD participated in a 3-month, individualized, moderate-intensity aerobic training on a treadmill (Walking)...
2017: Journal of Alzheimer's Disease: JAD
Zhongyan Hu, Jinhuan Dong, Yang Men, Yifei Li, Xianxiu Xu
A DBU-catalyzed aerobic oxidative Robinson annulation of 2-isocyanochalcones with active methylene ketones was developed for the expedient synthesis of phenanthridines in high to excellent yields. This unprecedented multistep domino reaction represents a new strategy for the construction of this tricyclic scaffold by the sequential formation of two rings and three C-C bonds in a single operation at room temperature.
January 20, 2017: Chemical Communications: Chem Comm
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