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ketones aerobic

Hai-Jun Zhang, Alexander W Schuppe, Shi-Tao Pan, Jin-Xiang Chen, Bo-Ran Wang, Timothy R Newhouse, Liang Yin
A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of ,- and ,-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity and good functional group tolerance. This method is additionally capable of oxidizing ,- and ,-unsaturated aldehydes, ketones, amides, nitriles and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. TMG was found to be crucial in its role as a base, but we also speculate it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst...
March 16, 2018: Journal of the American Chemical Society
Gangam Srikanth Kumar, Diksha Singh, Manish Kumar, Manmohan Kapur
We report herein, an unprecedented and expedient Pd-catalyzed oxidative coupling of allyl alcohols with anilines to afford β-amino ketones which are converted into substituted quinolines in a one-pot fashion. The exclusive preference for N-alkylation over N-allylation makes this approach unique, when compared to those reported in literature. Detailed mechanistic investigations reveal that the conjugate addition pathway was the predominant one over the allylic amination pathway. The notable aspects of the present approach are the use of readily available, bench-stable, allyl alcohols and molecular oxygen as the terminal oxidant, in the process dispensing the need for unstable and costly enones...
March 13, 2018: Journal of Organic Chemistry
Arvind Kumar Yadav, Krishna Nand Singh
A novel and practical synthesis of α-trifluoromethylthio-substituted ketones has been accomplished through the visible-light-induced aerobic oxidation of styrenes. The protocol employs the combination of CF3SO2Na and CS2 as a new source of SCF3 radicals in the presence of eosin Y as a photoredox catalyst.
February 5, 2018: Chemical Communications: Chem Comm
Aaron Webster Puri, Emily Mevers, Timothy R Ramadhar, Daniel Petras, Darren Liu, Joern Piel, Pieter C Dorrestein, Peter Greenberg, Mary E Lidstrom, Jon Clardy
Methane-oxidizing bacteria, aerobes that utilize methane as their sole carbon and energy source, are increasingly studied for their environmentally significant ability to remove methane from the atmosphere. Their genomes indicate that they also have a robust and unusual secondary metabolism. Bioinformatic analysis of the Methylobacter tundripaludum genome identified biosynthetic gene clusters for several intriguing metabolites, and this report discloses the structural and genetic characterization of tundrenone, one of these metabolites...
January 23, 2018: Journal of the American Chemical Society
J Vijaya Sundar, M Kamaraj, V Subramanian
Functionalized graphene materials are well known for their application in catalyzing the aerobic oxidation of alcohols, hydrocarbons, etc. in an aqueous medium. Despite the fact that a few catalysts are known to oxidize thiols to disulfides, their selectivity is poor and requires oxidants that are not suitable in terms of the principles of green chemistry. Therefore, in this context, an attempt has been made to investigate the possibility of utilizing nitrogen doped graphene for the aerobic oxidation of thiols to disulfides using density functional theory (DFT)...
January 4, 2018: Physical Chemistry Chemical Physics: PCCP
Soumitra Ghosh, Erika Castillo, Elma S Frias, Raymond A Swanson
Microglia have diverse actions, ranging from synapse pruning in development to cytotoxic effects in disease. Brain energy metabolism and substrate availability vary under normal and disease states, but how these variations influence microglial function is relatively unknown. Microglia, like most other cell types, express the full complement of gene products required for both glycolytic and oxidative metabolism. Evidence suggests that microglia increase aerobic glycolysis and decrease respiration when activated by various stimuli...
December 8, 2017: Glia
Wuyuan Zhang, Jenő Gacs, Isabel W C E Arends, Frank Hollmann
The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible under these conditions.
October 23, 2017: ChemCatChem
Han Li, Ruiwen Jin, Yawei Li, Aishun Ding, Xinqi Hao, Hao Guo
In this work, we developed a new method for the transformation of organostannanes via radical process. In this reaction, highly reactive carbon radical species can be efficiently generated through HBr-catalyzed photocleavage of C-Sn bond via single electron transfer process. Under aerobic conditions, the in situ formed primary/secondary alkyl radicals can be further highly selectively oxidized into carboxylic acids/ketones, respectively.
November 29, 2017: Scientific Reports
Zhen Yin, Yumei Zheng, Hong Wang, Jianxin Li, Qingjun Zhu, Ye Wang, Na Ma, Gang Hu, Benqiao He, Axel Knop-Gericke, Robert Schlögl, Ding Ma
Electrochemical oxidation has attracted vast interest 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) Co3 O4 nanowires (NWs) on the conductive porous Ti membrane (Co3 O4 NWs/Ti) via the combination of a facile hydrothermal synthesis and subsequent thermal treatment...
December 26, 2017: ACS Nano
Benito Alcaide, Pedro Almendros, 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 evidence strongly suggest the involvement of radical species in the transformation.
December 6, 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...
August 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
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