keyword
MENU ▼
Read by QxMD icon Read
search

Electrophilic

keyword
https://www.readbyqxmd.com/read/27933224/2-diazo-1-phenyl-2-trifluoromethyl-sulfonyl-ethan-1-one-another-utility-for-electrophilic-trifluoromethylthiolation-reactions
#1
Zhongyan Huang, Kenta Okuyama, Chen Wang, Etsuko Tokunaga, Xiaorui Li, Norio Shibata
2-Diazo-1-phenyl-2-((trifluoromethyl)sulfonyl)ethan-1-one (diazo-triflone) (2) is not only a building block but also a reagent. In this study, diazo-triflone, which was originally used for the synthesis of β-lactam triflones as a trifluoromethanesulfonyl (SO2CF3) building block under catalyst-free thermal conditions, is redisclosed as an effective electrophilic trifluoromethylthiolation reagent under copper catalysis. A broad set of enamines, indoles, β-keto esters, pyrroles, and anilines were nicely transformed into corresponding trifluoromethylthio (SCF3) compounds in good to high yields by diazo-triflone under copper catalysis via an electrophilic-type reaction...
June 2016: ChemistryOpen
https://www.readbyqxmd.com/read/27931001/microbial-fuel-cell-operation-using-monoazo-and-diazo-dyes-as-terminal-electron-acceptor-for-simultaneous-decolourisation-and-bioelectricity-generation
#2
Yoong-Sin Oon, Soon-An Ong, Li-Ngee Ho, Yee-Shian Wong, Yoong-Ling Oon, Harvinder Kaur Lehl, Wei-Eng Thung, Noradiba Nordin
Monoazo and diazo dyes [New coccine (NC), Acid orange 7 (AO7), Reactive red 120 (RR120) and Reactive green 19 (RG19)] were employed as electron acceptors in the abiotic cathode of microbial fuel cell. The electrons and protons generated from microbial organic oxidation at the anode which were utilized for electrochemical azo dye reduction at the cathodic chamber was successfully demonstrated. When NC was employed as the electron acceptor, the chemical oxygen demand (COD) removal and dye decolourisation efficiencies obtained at the anodic and cathodic chamber were 73±3% and 95...
November 28, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/27930886/histone-adduction-and-its-functional-impact-on-epigenetics
#3
James J Galligan, Lawrence J Marnett
Bioactive electrophiles generated from the oxidation of endogenous and exogenous compounds are a contributing factor in numerous disease states. Their toxicity is largely attributed to the covalent modification of cellular nucleophiles, including protein and DNA. With regard to protein modification, the side-chains of Cys, His, Lys, and Arg residues are critical targets. This results in the generation of undesired protein post-translational modifications (PTMs), that can trigger dire cellular consequences. Notably, histones are Lys- and Arg-rich proteins, providing a fertile source for adduction by both exogenous and endogenous electrophiles...
December 8, 2016: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/27929522/merging-allylic-c-h-bond-activation-and-c-c-bond-cleavage-en-route-to-the-formation-of-a-quaternary-carbon-stereocenter-in-acyclic-systems
#4
Alexandre Vasseur, Ilan Marek
This protocol describes a diastereoselective approach for the synthesis of complex molecular architectures containing two stereogenic centers in a 1,4 relationship, one of which being an all-carbon quaternary stereogenic center. Such molecules could be intermediates in the synthesis of steroids, for example. Conceived as a single-flask synthetic sequence from ω-ene cyclopropanes, the protocol involves a concerted allylic C-H and C-C bond activation promoted by the Negishi reagent (Cp2Zr(η(2)-butene)). This zirconium-promenade-based procedure affords bifunctionalized products in high diastereomeric ratios after reaction of ω-ene cyclopropanes with the Negishi complex, followed by a thermal treatment and sequential addition of two different electrophiles...
January 2017: Nature Protocols
https://www.readbyqxmd.com/read/27923813/the-chemical-basis-of-thiol-addition-to-nitro-conjugated-linoleic-acid-a-protective-cell-signaling-lipid
#5
Lucia Turell, Dario A Vitturi, E Laura Coitiño, Lourdes Lebrato, Matias N Moller, Camila Sagasti, Sonia R Salvatore, Steven R Woodcock, Beatriz Alvarez, Francisco J Schopfer
Nitroalkene fatty acids are formed in vivo and exert protective and anti-inflammatory effects via reversible Michael addition to thiol-containing proteins in key signaling pathways. Nitro-conjugated linoleic acid (NO2-CLA) is preferentially formed, constitutes the most abundant nitrated fatty acid in humans and contains two carbons that could potentially react with thiols, modulating signaling actions and levels. In this work, we examined the reactions of NO2-CLA with low molecular weight thiols (glutathione, cysteine, homocysteine, cysteinylglycine and β mercaptoethanol) and human serum albumin (HSA)...
December 6, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27918634/generation-and-application-of-homoenolate-equivalents-utilizing-1-2-phospha-brook-rearrangement-under-br%C3%A3-nsted-base-catalysis
#6
Azusa Kondoh, Takuma Aoki, Masahiro Terada
A novel method for catalytic generation of a homoenolate equivalent and its application to carbon-carbon bond formation was developed by utilizing the [1,2]-phospha-Brook rearrangement under Brønsted base catalysis. The α-oxygenated allyl anions, which can serve as homoenolate equivalents, were catalytically generated in situ by treating readily available chalcones with diethyl phosphite or the pre-formed 1,2-adducts of diethyl phosphite with chalcones in the presence of a catalytic amount of a phosphazene base, P2-tBu...
December 5, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27918440/a-computational-study-of-structure-and-reactivity-of-n-substitued-4-piperidones-curcumin-analogues-and-their-radical-anions
#7
Maximiliano Martínez-Cifuentes, Boris Weiss-López, Ramiro Araya-Maturana
In this work, a computational study of a series of N-substitued-4-piperidones curcumin analogues is presented. The molecular structure of the neutral molecules and their radical anions, as well as their reactivity, are investigated. N-substituents include methyl and benzyl groups, while substituents on the aromatic rings cover electron-donor and electron-acceptor groups. Substitutions at the nitrogen atom do not significantly affect the geometry and frontier molecular orbitals (FMO) energies of these molecules...
December 2, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27916959/a-molecular-electron-density-theory-study-of-the-chemical-reactivity-of-cis-and-trans-resveratrol
#8
Juan Frau, Francisco Muñoz, Daniel Glossman-Mitnik
The chemical reactivity of resveratrol isomers with the potential to play a role as inhibitors of the nonenzymatic glycation of amino acids and proteins, both acting as antioxidants and as chelating agents for metallic ions such as Cu, Al and Fe, have been studied by resorting to the latest family of Minnesota density functionals. The chemical reactivity descriptors have been calculated through Molecular Electron Density Theory encompassing Conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices, the dual descriptor f ( 2 ) ( r ) and the electrophilic and nucleophilic Parr functions...
December 1, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27914365/developing-piperlongumine-directed-glutathione-s-transferase-inhibitors-by-an-electrophilicity-based-strategy
#9
Hai-Bo Wang, Xiao-Ling Jin, Jia-Fang Zheng, Fu Wang, Fang Dai, Bo Zhou
We report a case of successful design of glutathione S-transferase (GST) inhibitors via a natural product-inspired and electrophilicity-based strategy. Based on this strategy, a novel piperlongumine analog (PL-13) bearing a para-trifluoromethyl group and an α-chlorine on its aromatic and lactam rings, respectively, surfaced as a promising GST inhibitor, thereby overcoming cisplatin resistance in lung cancer A549 cells.
November 15, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27913584/nitro-fatty-acid-pharmacokinetics-in-the-adipose-tissue-compartment
#10
Marco Fazzari, Nicholas K H Khoo, Steven R Woodcock, Diane K Jorkasky, Lihua Li, Francisco J Schopfer, Bruce A Freeman
Electrophilic nitro-fatty acids (NO2-FAs) promote adaptive and anti-inflammatory cell signaling responses as a result of an electrophilic character that supports post-translational protein modifications. A unique pharmacokinetic profile is expected for NO2-FAs because of an ability to undergo reversible reactions including Michael additions with biological cysteine-containing proteins and esterification into complex lipids. Herein we report via quantitative whole-body autoradiography analysis of rats gavaged with radiolabeled 10-nitro-[14C]oleic acid, preferential accumulation in adipose tissue over two weeks...
December 2, 2016: Journal of Lipid Research
https://www.readbyqxmd.com/read/27913278/molecular-basis-for-the-dual-subcellular-distribution-of-microsomal-glutathione-transferase-1
#11
Miyuki Shimoji, Ricardo A Figueroa, Etienne Neve, Danuta Maksel, Gabriela Imreh, Ralf Morgenstern, Einar Hallberg
Microsomal glutathione transferase 1 (MGST1) is a membrane bound enzyme involved in the detoxification of reactive electrophiles and protection of membranes from oxidative stress. The enzyme displays an unusual and broad subcellular distribution with especially high levels in the endoplasmic reticulum (ER) and outer mitochondrial membrane (OMM). Here we examined the molecular basis for this dual distribution. We hypothesized that the amphipathic properties of the first transmembrane segment (TMS), that contains a positively charged lysine (K25), is a central feature guiding dual targeting...
November 29, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27911781/structure-and-mechanism-of-nov1-a-resveratrol-cleaving-dioxygenase
#12
Ryan P McAndrew, Noppadon Sathitsuksanoh, Michael M Mbughuni, Richard A Heins, Jose H Pereira, Anthe George, Kenneth L Sale, Brian G Fox, Blake A Simmons, Paul D Adams
Stilbenes are diphenyl ethene compounds produced naturally in a wide variety of plant species and some bacteria. Stilbenes are also derived from lignin during kraft pulping. Stilbene cleavage oxygenases (SCOs) cleave the central double bond of stilbenes, forming two phenolic aldehydes. Here, we report the structure of an SCO. The X-ray structure of NOV1 from Novosphingobium aromaticivorans was determined in complex with its substrate resveratrol (1.89 Å), its product vanillin (1.75 Å), and without any bound ligand (1...
November 30, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27910977/acylboranes-synthetic-strategies-and-applications
#13
REVIEW
Florian Korbinian Scharnagl, Shubhankar Kumar Bose, Todd B Marder
An overview of the synthesis and chemistry of acylborane compounds is presented. Acylboranes are a rare class of boron compounds, previously proposed as intermediates in several transformations and considered to be difficult to prepare. Methodologies for the preparation of acylborane compounds are based on both electrophilic and nucleophilic sources of boron. The former methods include addition of electrophilic boron reagents to acyl-anion equivalents, while the latter methods are based on boryl anion reagents which are trapped by electrophiles, such as aldehydes, diethyl carbonate and ethyl acetate...
December 2, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27910176/visible-light-accelerated-c-h-sulfinylation-of-heteroarenes
#14
Andreas Uwe Meyer, Alexander Wimmer, Burkhard König
Heteroaromatic sulfoxides are a frequent structural motif in natural products, drugs, catalysts, and materials. We report a metal-free visible-light-accelerated synthesis of heteroaromatic sulfoxides from sulfinamides and peroxodisulfate. The reaction proceeds at room temperature with blue-light irradiation and allows the C-H sulfinylation of electron-rich heteroarenes, such as pyrroles and indoles. An electrophilic aromatic substitution mechanism is proposed based on the substrate scope, substitution selectivity, and competition experiments with different nucleophiles...
December 2, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27906528/a-new-domain-of-reactivity-for-high-valent-dinuclear-m-%C3%AE-o-2-m-complexes-in-oxidation-reactions
#15
Xenia Engelmann, Shenglai Yao, Erik R Farquhar, Tibor Szilvási, Uwe Kuhlmann, Peter Hildebrandt, Matthias Driess, Kallol Ray
The strikingly different reactivity of a series of homo- and heterodinuclear [(M(III) )(μ-O)2 (M(III) )'](2+) (M=Ni; M'=Fe, Co, Ni and M=M'=Co) complexes with β-diketiminate ligands in electrophilic and nucleophilic oxidation reactions is reported, and can be correlated to the spectroscopic features of the [(M(III) )(μ-O)2 (M(III) )'](2+) core. In particular, the unprecedented nucleophilic reactivity of the symmetric [Ni(III) (μ-O)2 Ni(III) ](2+) complex and the decay of the asymmetric [Ni(III) (μ-O)2 Co(III) ](2+) core through aromatic hydroxylation reactions represent a new domain for high-valent bis(μ-oxido)dimetal reactivity...
December 1, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27906174/therapeutic-advantage-of-pro-electrophilic-drugs-to-activate-the-nrf2-are-pathway-in-alzheimer-s-disease-models
#16
Stuart A Lipton, Tayebeh Rezaie, Anthony Nutter, Kevin M Lopez, James Parker, Kunio Kosaka, Takumi Satoh, Scott R McKercher, Eliezer Masliah, Nobuki Nakanishi
Alzheimer's disease (AD) is characterized by synaptic and neuronal loss, which occurs at least partially through oxidative stress induced by oligomeric amyloid-β (Aβ)-peptide. Carnosic acid (CA), a chemical found in rosemary and sage, is a pro-electrophilic compound that is converted to its active form by oxidative stress. The active form stimulates the Keap1/Nrf2 transcriptional pathway and thus production of phase 2 antioxidant enzymes. We used both in vitro and in vivo models. For in vitro studies, we evaluated protective effects of CA on primary neurons exposed to oligomeric Aβ...
December 1, 2016: Cell Death & Disease
https://www.readbyqxmd.com/read/27904089/structure-cytotoxicity-relationship-of-methacrylate-based-resin-monomers-as-evaluated-by-an-anti-oxidant-responsive-element-luciferase-reporter-assay
#17
Miki Egashira, Takahiro Suzuki, Ai Orimoto, Tohru Obata, Hiroshi Nakamura, Motohiro Tanaka, Takao Kanamori, Tatsushi Kawai
To investigate the chemical structure-cytotoxicity relationship of methacrylate-based resin monomers, we studied their effects on anti-oxidant responsive element (ARE)-mediated transcription. HepG2 cells stably expressing an ARE-regulated luciferase reporter gene were cultured for 6 h with various concentrations of several resin monomers and subjected to a luciferase assay. The doseresponse curves observed for hydrophobic monomers with different hydrocarbon chains (MMA, EMA, PMA and BMA) began to rise at concentrations between 0...
2016: Dental Materials Journal
https://www.readbyqxmd.com/read/27903430/minimizing-the-risk-of-chemically-reactive-metabolite-formation-of-new-drug-candidates-implications-for-preclinical-drug-design
#18
Andreas Brink, Axel Pähler, Christoph Funk, Franz Schuler, Simone Schadt
Many pharmaceutical companies aim to reduce reactive metabolite formation by chemical modification at early stages of drug discovery. A practice often applied is the detection of stable trapping products of electrophilic intermediates with nucleophilic trapping reagents to guide rational structure-based drug design. This contribution delineates this strategy to minimize the potential for reactive metabolite formation of clinical candidates during preclinical drug optimization, exemplified by the experience at Roche over the past decade...
November 27, 2016: Drug Discovery Today
https://www.readbyqxmd.com/read/27903227/chemistry-of-heterocyclic-five-and-six-membered-enamino-nitriles-and-enamino-esters
#19
Moustafa Sherief Moustafa, Saleh Mohammed Al-Mousawi, Hesham R El-Seedi, Mohamed Hilmy Elnagdi
Progress in chemistry synthetic methodologies of cyclic enaminonitriles is reported. Due to this progress, it becomes possible to reactivate these molecules toward electrophiles, nucleophiles and as electron rich dienes in 2+3 dipolar additions and in 4+2 cycloadditions reactions. Synthetizing the polyfunctionalized 4H-pyrans and their fused derivatives is a fascinating field with a multitude of biological implications such as antitumor, cardiotonic, hepatoprotective, antihypertensive, antibronchitis, as well antifungal activity...
November 29, 2016: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/27902862/nucleophilic-transfer-reactions-of-the-si-c2-f5-3-moiety
#20
Nico Schwarze, Simon Steinhauer, Beate Neumann, Hans-Georg Stammler, Berthold Hoge
The tris(pentafluoroethyl)silanide anion is accessible by the deprotonation of Si(C2 F5 )3 H at low temperatures. Subsequent quenching of the resulting salt-like compounds with suitable electrophiles, such as transition-metal complexes or Group 14 element halides, leads to a plethora of novel tris(pentafluoroethyl)silane derivatives. This underlines the versatility of Li[Si(C2 F5 )3 ] as a powerful nucleophilic transfer reagent.
November 30, 2016: Angewandte Chemie
keyword
keyword
81299
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"