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https://www.readbyqxmd.com/read/28231419/absolute-photoionization-cross-sections-of-two-cyclic-ketones-cyclopentanone-cyclohexanone
#1
Chelsea Price, Yasmin Fathi, Giovanni Meloni
Absolute photoionization cross sections for cyclopentanone and cyclohexanone, as well as partial ionization cross sections for the dissociative ionized fragments, are presented in this investigation. Experiments are performed via a multiplexed photoionization mass spectrometer utilizing VUV synchrotron radiation supplied by the Advanced Light Source of Lawrence Berkeley National Laboratory. These results allow the quantification of these species that is relevant to investigate the kinetics and combustion reactions of potential biofuels...
February 23, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28231176/volatile-composition-of-smoked-and-non-smoked-iranian-rice
#2
Leontina Lipan, Mohammad Hojjati, Hussein El-Zaeddi, Lucía Sánchez-Rodríguez, Ángel Antonio Carbonell-Barrachina
In this work, the volatile profiles of smoked and non-smoked Iranian rice were identified, and their relative abundance was calculated and compared. Headspace solid-phase microextraction together with gas chromatography-mass spectrometry (SPME-GC-MS) were used to extract and identify the volatile compounds. The main groups of volatiles in Iranian rice were aldehydes, ketones, phenol derivatives, furans, linear hydrocarbons, esters and terpenes. The chemical family aldehydes was the most abundant one in the profile of non-smoked rice, while phenol derivatives and furans predominated in smoked samples...
November 30, 2016: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28231138/essential-oils-in-foods-from-ancient-times-to-the-21st-century
#3
EDITORIAL
Esther Sendra
Medicinal plants and culinary herbs have been used since ancient times. Essential oils (EO) are a mixture of numerous compounds, mainly terpenes, alcohols, acids, esters, epoxides, aldehydes, ketones,aminesandsulfides,thatareprobablyproducedbyplantsasaresponsetostress[1].[...].
June 14, 2016: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28229143/metal-free-nitroxyl-radical-mediated-%C3%AE-c-sp-3-h-amination-of-saturated-ketones-with-heteroaryl-halides-multiple-roles-of-tempo
#4
Ping Qian, Yu Deng, Haibo Mei, Jianlin Han, Yi Pan
The first metal-free nitroxyl-radical-mediated β-amination of saturated ketones by using heteroaryl halides as amide precursors has been developed. This reaction proceeds through a cascade α-aminoxylation/Cope-like elimination/aza-Michael addition sequence to afford β-amino ketone derivatives with excellent yields. TEMPO plays multiple roles in the current β-amination process, including those of an oxidant, an α-aminoxylation reagent, a β-hydrogen acceptor, an in situ base, and an oxygen source.
February 23, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28228852/3d-printed-fluidics-with-embedded-analytic-functionality-for-automated-reaction-optimisation
#5
Andrew J Capel, Andrew Wright, Matthew J Harding, George W Weaver, Yuqi Li, Russell A Harris, Steve Edmondson, Ruth D Goodridge, Steven D R Christie
Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28226207/transition-metal-free-oxidative-decarboxylative-cross-coupling-of-alpha-beta-unsaturated-carboxylic-acids-with-cyclic-ethers-under-air-conditions-mild-synthesis-of-alpha-oxyalkyl-ketones
#6
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 included C-C and C=O bond formation in one step through addition, oxidation and decarboxylation processes, leading to the desired ketone products in moderate to excellent yields. In addition, mechanism researches showed that the transformation process undergone a radical pathway via a direct activation of α-sp3 C-H bond of oxygen of cyclic ether...
February 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28226195/global-transcriptional-response-of-human-liver-cells-to-ethanol-stress-of-different-strength-reveals-hormetic-behavior
#7
Wolfgang Schmidt-Heck, Eva C Wönne, Thomas Hiller, Uwe Menzel, Dirk Koczan, Georg Damm, Daniel Seehofer, Fanny Knöspel, Nora Freyer, Reinhard Guthke, Steven Dooley, Katrin Zeilinger
BACKGROUND: The liver is the major site for alcohol metabolism in the body and therefore, the primary target organ for ethanol-induced toxicity. In this study, we investigated the in vitro response of human liver cells to different ethanol concentrations in a perfused bioartificial liver device that mimics the complex architecture of the natural organ. METHODS: Primary human liver cells were cultured in the bioartificial liver device and treated for 24 hours with medium containing 150 mM (low), 300 mM (medium) or 600 mM (high) ethanol, while a control culture was kept untreated...
February 22, 2017: Alcoholism, Clinical and Experimental Research
https://www.readbyqxmd.com/read/28225279/cubr-catalyzed-aerobic-decarboxylative-cycloaddition-for-the-synthesis-of-indolizines-under-solvent-free-conditions
#8
Wenhui Wang, Junwen Han, Jinwei Sun, Yun Liu
An efficient synthesis of diversified indolizine derivatives were 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 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28225270/construction-of-the-bacteriochlorin-macrocycle-with-concomitant-nazarov-cyclization-to-form-the-annulated-isocyclic-ring-analogues-of-bacteriochlorophyll-a
#9
Shaofei Zhang, Jonathan S Lindsey
Bacteriochlorophylls contain a bacteriochlorin macrocycle bearing an annulated fifth ring. The fifth ring, termed the isocyclic ring or ring E, is equipped with 13(1)-oxo and 13(2)-carbomethoxy substituents. Herein, a general route to stable, synthetic bacteriochlorophyll analogues is described. Knoevenagel condensation (∼40 mM, rt, CH2Cl2, piperidine/AcOH/molecular sieves) of a dihydrodipyrrin-carboxaldehyde (AD half) and a dihydrodipyrrin substituted with a β-ketoester (BC half) forms a propenone bearing the two halves (a hydrobilin analogue)...
February 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28225253/glutathione-adduct-patterns-of-michael-acceptor-carbonyls
#10
Christian Slawik, Christiane Rickmeyer, Martin Brehm, Alexander Böhme, Gerrit Schüürmann
Glutathione (GSH) has so far been considered to facilitate detoxification of soft organic electrophiles through covalent binding at its cysteine (Cys) thiol group, followed by stepwise catalyzed degradation and eventual elimination along the mercapturic acid pathway. Here we show that in contrast to expectation from HSAB theory, Michael-acceptor ketones, aldehydes and esters may form also single, double and triple adducts with GSH involving β-carbon attack at the much harder N-terminus of the γ-glutamyl (Glu) unit of GSH...
February 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28225181/two-phase-reactions-in-microdroplets-without-the-use-of-phase-transfer-catalysts
#11
Xin Yan, Heyong Cheng, Richard N Zare
Many important chemical transformations occur in two-phase reactions, which are widely used in chemical, pharmaceutical, and polymer manufacturing. We present an efficient method for performing two-phase reactions in microdroplets sheared by sheath gas without using a phase-transfer catalyst. This avoids disadvantages such as thermal instability, high cost, and, especially, the need to separate and recycle the catalysts. We show that various alcohols can be oxidized to the corresponding aldehydes and ketones within milliseconds in moderate to good yields (50-75 %)...
February 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28221041/dialkyl-phosphite-initiated-cyclopropanation-of-%C3%AE-%C3%AE-unsaturated-ketones-using-%C3%AE-ketoesters-or-isatin-derivatives
#12
Deng Yin, Hui Liu, Chong-Dao Lu, Yan-Jun Xu
Efficient cyclopropanation of α,β-unsaturated ketones using α-ketoesters or isatin derivatives is reported. The cyclopropanation reaction occurs via a cascade transformation that starts with addition of deprotonated dialkyl phosphite to the keto groups of α-ketoesters or isatin derivatives, followed by [1,2]-phosphonate/phosphate rearrangement to generate α-phosphonyloxyenolate intermediates, which are trapped by α,β-unsaturated ketones via Michael addition/ring closure. This protocol was used to synthesize tetra-substituted cyclopropanes with a 1,2-cis-1,3-trans configuration in high yield with excellent diastereoselectivity...
February 21, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28221034/regioselective-1-4-conjugate-addition-of-grignard-reagents-to-%C3%AE-%C3%AE-%C3%AE-%C3%AE-dienones-and-%C3%AE-%C3%AE-%C3%AE-%C3%AE-dienyl-thiol-esters
#13
Emmanuel Amoah, R Karl Dieter
Alkyl Grignard reagents (Et, nBu, iPr, cyclohexyl), with the exception of tBuMgCl, undergo exclusive or exceptionally highly regioselective 1,4-addition reactions to α,β-γ,δ-unsaturated ketones, while aryl and heteroaryl Grignard reagents give mixed results ranging from exclusive 1,4-addition (1-naphthyl, 2-N-methylpyrrolyl) to regioselective 1,2-addition (2-furyl, 2:1). All alkyl, aryl, and heteroaryl Grignard reagents examined gave exclusive 1,4-addition reactions with α,β-γ,δ-unsaturated thiol esters, with the exception of tBuMgCl which gave an 80:20 mixture of 1,4-:1,6-addition products...
February 21, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28220263/characterization-and-outcome-of-41-patients-with-beta-ketothiolase-deficiency-10%C3%A2-years-experience-of-a-medical-center-in-northern-vietnam
#14
Khanh Ngoc Nguyen, Elsayed Abdelkreem, Roberto Colombo, Yuki Hasegawa, Ngoc Thi Bich Can, Thao Phuong Bui, Hai Thanh Le, Mai Thi Chi Tran, Hoan Thi Nguyen, Hung Thanh Trinh, Yuka Aoyama, Hideo Sasai, Seiji Yamaguchi, Toshiyuki Fukao, Dung Chi Vu
Beta-ketothiolase (T2) deficiency is an inherited disease of isoleucine and ketone body metabolism caused by mutations in the ACAT1 gene. Between 2005 and 2016, a total of 41 patients with T2 deficiency were identified at a medical center in northern Vietnam, with an estimated incidence of one in 190,000 newborns. Most patients manifested ketoacidotic episodes of varying severity between 6 and 18 months of age. Remarkably, 28% of patients showed high blood glucose levels (up to 23.3 mmol/L). Ketoacidotic episodes recurred in 43% of patients...
February 20, 2017: Journal of Inherited Metabolic Disease
https://www.readbyqxmd.com/read/28220169/mg-ome-2-promoted-allylic-isomerization-of-%C3%AE-hydroxy-%C3%AE-%C3%AE-alkenoic-esters-to-synthesize-%C3%AE-ketone-esters
#15
Luhao Lai, A-Ni Li, Jiawei Zhou, Yarong Guo, Li Lin, Wei Chen, Rui Wang
This work concerns the Mg(OMe)2 promoted allylic isomerization of γ-hydroxy-α,β-alkenoic esters with TMEDA as an additive. The isomerization proceeded under mild conditions and afforded γ-keto esters in high yield (up to 96%) within 2 h. Both (Z)- and (E)-γ-hydroxy-α,β-alkenoic esters were tolerated under the reaction conditions. This transformation involves the in situ formation of a dienolate intermediate from the easily accessible γ-hydroxy-α,β-alkenoic ester. The in situ generated dienolate can react with benzaldehyde and undergo a practical, useful tandem allylic isomerization-Aldol reaction to afford more functionalized compounds...
February 21, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28219798/integrative-hepatoprotective-efficacy-comparison-of-raw-and-vinegar-baked-radix-bupleuri-using-nuclear-magnetic-resonance-based-metabolomics
#16
Jie Xing, Hui-Min Sun, Jin-Ping Jia, Xue-Mei Qin, Zhen-Yu Li
Radix Bupleuri (RB), with a Chinese name Chaihu, is one of the most popular Traditional Chinese herbal drug. It can be baked with vinegar to afford vinegar-baked Radix Bupleuri (VBRB), which is used in Traditional Chinese Medicine (TCM) for liver diseases treatment. In the present study, nuclear magnetic resonance-based metabolomic approach was used to compare the liver protective effect of RB and two types of VBRBs, which were prepared by two kinds of vinegar. The contents of 14 metabolites in the liver of carbon tetrachloride (CCl4) treated mice were significantly altered in comparison with control group, and VBRB prepared by Shanxi vinegar showed best effect as revealed by the amount and regulatory degree of the perturbed metabolites...
February 7, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28219012/the-tyrosinase-catalyzed-oxidation-of-the-leukoderma-inducing-agent-raspberry-ketone-produces-e-4-3-oxo-1-butenyl-1-2-benzoquinone-implications-for-melanocyte-toxicity
#17
Shosuke Ito, Maki Hinoshita, Erina Suzuki, Makoto Ojika, Kazumasa Wakamatsu
The exposure of human skin to 4-(4-hydroxyphenyl)-2-butanone (raspberry ketone, RK) is known to cause chemical/occupational leukoderma. RK has a structure closely related to 4-(4-hydroxyphenyl)-2-butanol (rhododendrol), a skin whitening agent that was found to cause leukoderma in the skin of consumers in 2013. Rhododendrol is a good substrate for tyrosinase and causes a tyrosinase-dependent cytotoxicity to melanocytes, cells that are responsible for skin pigmentation. Therefore, it is expected that RK exerts its cytotoxicity to melanocytes through the tyrosinase-catalyzed oxidation to cytotoxic o-quinones...
February 20, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28218911/expanding-the-product-portfolio-of-fungal-type-i-fatty-acid-synthases
#18
Zhiwei Zhu, Yongjin J Zhou, Anastasia Krivoruchko, Martin Grininger, Zongbao K Zhao, Jens Nielsen
Fungal type I fatty acid synthases (FASs) are mega-enzymes with two separated, identical compartments, in which the acyl carrier protein (ACP) domains shuttle substrates to catalytically active sites embedded in the chamber wall. We devised synthetic FASs by integrating heterologous enzymes into the reaction chambers and demonstrated their capability to convert acyl-ACP or acyl-CoA from canonical fatty acid biosynthesis to short/medium-chain fatty acids and methyl ketones.
February 20, 2017: Nature Chemical Biology
https://www.readbyqxmd.com/read/28218536/polar-ketone-functionalized-metal-organic-framework-showing-a-high-co2-adsorption-performance
#19
Genfeng Feng, Yuxin Peng, Wei Liu, Feifan Chang, Yafei Dai, Wei Huang
The incorporation of various functionalities into porous metal-organic frameworks (MOFs) represents an efficacious strategy to improving their gas adsorption properties. In this work, a carbonylated tetracarboxylic acid ligand (5,5'-carbonyldiisophthalic acid) was synthesized, and a ketone-functionalized MOF with exposed metal sites based on this ligand was formed successfully. Structural analysis reveals that the new MOF possesses channels decorated by the carbonyl groups and rhombicuboctahedral cages, with open Cu(II) sites pointing toward the cage center...
February 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28218522/one-pot-cascade-synthesis-of-substituted-carbazoles-from-indoles-ketones-and-alkenes-using-oxygen-as-the-oxidant
#20
Shanping Chen, Yuxia Li, Penghui Ni, Baichuan Yang, Huawen Huang, Guo-Jun Deng
An efficient one-pot two-step indole-to-carbazole strategy has been developed. This transition metal-free methodology uses oxygen as the sole oxidant and starts from cheap and readily available indoles, ketones and alkenes. The present protocol efficiently enables the assembly of a diverse array of substituted carbazole products with good regioselectivity and broad tolerance of functional groups.
February 20, 2017: Journal of Organic Chemistry
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