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agents halogénés

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https://www.readbyqxmd.com/read/28730190/comparison-of-halide-receptors-based-on-h-halogen-chalcogen-pnicogen-and-tetrel-bonds
#1
Steve Scheiner
A series of halide receptors are constructed and the geometries and energetics of their binding to F(-), Cl(-), and Br(-) assessed by quantum calculations. The dicationic receptors are based on a pair of imidazolium units, connected via a benzene spacer. The imidazoliums each donate a proton to a halide in a pair of H-bonds. Replacement of the two bonding protons by Br leads to binding via a pair of halogen bonds. Likewise, chalcogen, pnicogen, and tetrel bonds occur when the protons are replaced, respectively, by Se, As, and Ge...
July 21, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28678283/a-quantitative-measure-of-halogen-bond-activation-in-cocrystallization
#2
Lucia Carlucci, Angelo Gavezzotti
A theoretical investigation of bond lengths and bond energies for several kinds of halogen bonding interactions is carried out using the PIXEL method. The effect of different kinds of activating agents, fluoro-, nitro-, ethynyl substitution and combinations thereof, is assessed quantitatively, and is found to be fully consistent with the results of literature screenings of the corresponding strengths, as judged by the ease of formation of cocrystals. In the best combination of activators the halogen bond is comparable or superior to a strong O-HO hydrogen bond in what concerns stabilization energies and stretching force constants...
July 5, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28672278/hydrazinyl-arylthiazole-based-pyridine-scaffolds-synthesis-structural-characterization-in%C3%A2-vitro-%C3%AE-glucosidase-inhibitory-activity-and-in-silico-studies
#3
Farman Ali, Khalid Mohammed Khan, Uzma Salar, Muhammad Taha, Nor Hadiani Ismail, Abdul Wadood, Muhammad Riaz, Shahnaz Perveen
Acarbose, miglitol, and voglibose are the inhibitors of α-glucosidase enzyme and being clinically used for the management of type-II diabetes mellitus. However, many adverse effects are also associated with them. So, the development of new therapeutic agents is an utmost interest in medicinal chemistry research. Current study is based on the identification of new α-glucosidase inhibitors. For that purpose, hydrazinyl arylthiazole based pyridine derivatives 1-39 were synthesized via two step reaction and fully characterized by spectroscopic techniques EI-MS, HREI-MS, (1)H-, and (13)C NMR...
June 26, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28672229/chloromethane-emissions-in-human-breath
#4
Frank Keppler, Jan Fischer, Tobias Sattler, Daniela Polag, Nicole Jaeger, Heinz Friedrich Schöler, Markus Greule
Chloromethane (CH3Cl), currently the most abundant chlorinated organic compound in the atmosphere at around ~550 parts per trillion by volume (pptv), is considered responsible for approximately 16% of halogen-catalyzed stratospheric ozone destruction. Although emissions of CH3Cl are known to occur from animals such as cattle, formation and release of CH3Cl from humans has not yet been reported. In this study a pre-concentration unit coupled with a gas chromatograph directly linked to a mass spectrometer was used to precisely measure concentrations of CH3Cl at the pptv level in exhaled breath from 31 human subjects with ages ranging from 3 to 87years...
June 30, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28662620/multisubstrate-specific-flavin-containing-monooxygenase-from-chlorella-pyrenoidosa-with-potential-application-for-phenolic-wastewater-remediation-and-biosensor-application
#5
Bhaskar Das, Sanjukta Patra
Microbial degradation of phenolic pollutants in industrial wastewater is dependent on enzymatic pathway comprising a cascade of phenol metabolizing enzymes. Phenol hydroxylase is the first enzyme of the pathway catalyzing the initial attack on phenol in green algae Chlorella pyrenoidosa. The present work reports cost effective production of partially purified microalgal phenol hydroylase by single step purification and characterization of its kinetic properties with the view of application for enzyme based remediation of phenolic wastewater or in phenolic biosensor...
June 30, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28661157/iron-iii-catalyzed-chlorination-of-activated-arenes
#6
Mohamed A B Mostafa, Rosalind M Bowley, Daugirdas T Racys, Martyn C Henry, Andrew Sutherland
A general and regioselective method for the chlorination of activated arenes has been developed. The transformation uses iron(III) triflimide as a powerful Lewis acid for the activation of N-chlorosuccinimide and the subsequent chlorination of a wide range of anisole, aniline, acetanilide, and phenol derivatives. The reaction was utilized for the late-stage mono- and dichlorination of a range of target compounds such as the natural product nitrofungin, the antibacterial agent chloroxylenol, and the herbicide chloroxynil...
July 3, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28657674/a-convergent-synthesis-of-functionalized-alkenyl-halides-through-cobalt-iii-catalyzed-three-component-c-h-bond-addition
#7
Jeffrey A Boerth, Jonathan A Ellman
A Co(III) -catalyzed three-component coupling of C(sp(2) )-H bonds, alkynes, and halogenating agents to give alkenyl halides is reported. This transformation proceeds with high regio- and diastereoselectivity, and is effective for a broad range of aryl and alkyl terminal alkynes. Diverse C-H bond partners also exhibit good reactivity for a range of heteroaryl and aryl systems as well as synthetically useful secondary and tertiary amide, urea, and pyrazole directing groups. This multicomponent transformation is also compatible with allenes in place of alkynes to furnish tetrasubstituted alkenyl halides, showcasing the first halo-arylation of allenes...
June 28, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28653831/detoxification-of-a-sulfur-mustard-simulant-using-a-bodipy-functionalized-zirconium-based-metal-organic-framework
#8
Ahmet Atilgan, Timur Islamoglu, Ashlee J Howarth, Joseph T Hupp, Omar K Farha
Effective detoxification of chemical warfare agents is a global necessity. As a powerful photosensitizer, a halogenated BODIPY ligand is postsynthetically appended to the Zr6 nodes of the metal-organic framework (MOF), NU-1000, to enhance singlet oxygen generation from the MOF. The BODIPY/MOF material is then used as a heterogeneous photocatalyst to produce singlet oxygen under green LED irradiation. The singlet oxygen selectively detoxifies the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), to the less toxic sulfoxide derivative (2-chloroethyl ethyl sulfoxide, CEESO) with a half-life of approximately 2 min...
July 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28636753/stable-bromiranium-ions-with-weakly-coordinating-counterions-as-efficient-electrophilic-brominating-agents
#9
Christoph Ascheberg, Jonathan Bock, Florenz Buß, Christian Mück-Lichtenfeld, Constantin B Daniliuc, Klaus Bergander, Fabian Dielmann, Ulrich Hennecke
Electrophilic halogenating agents are an important class of reagents in chemical synthesis. Herein, we show that sterically demanding bromiranium ions with weakly coordinating counterions are highly reactive electrophilic brominating agents. Despite their high reactivity these reagents are stable, in one case even under ambient conditions and can be applied in electrophilic halogenations of alkenes as well as heteroatoms.
June 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28624672/analysis-of-fire-deaths-in-poland-and-influence-of-smoke-toxicity
#10
Joanna Giebułtowicz, Monika Rużycka, Piotr Wroczyński, David A Purser, Anna A Stec
Dwelling fires have changed over the years because building contents and the materials used in then have changed. They all contribute to an ever-growing diversity of chemical species found in fires, many of them highly toxic. These arise largely from the changing nature of materials in interior finishes and furniture, with an increasing content of synthetic materials containing higher levels of nitrogen, halogen and phosphorus additives. While there is still a belief that carbon monoxide is the major lethal toxic agent in fires, the hydrogen cyanide and acid gases released from these additives are now well-recognised as major contributory causes of incapacitation, morbidity and mortality in domestic fires...
June 9, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28607510/asymmetric-suzuki-miyaura-coupling-of-heterocycles-via-rhodium-catalysed-allylic-arylation-of-racemates
#11
Philipp Schäfer, Thomas Palacin, Mireia Sidera, Stephen P Fletcher
Using asymmetric catalysis to simultaneously form carbon-carbon bonds and generate single isomer products is strategically important. Suzuki-Miyaura cross-coupling is widely used in the academic and industrial sectors to synthesize drugs, agrochemicals and biologically active and advanced materials. However, widely applicable enantioselective Suzuki-Miyaura variations to provide 3D molecules remain elusive. Here we report a rhodium-catalysed asymmetric Suzuki-Miyaura reaction with important partners including aryls, vinyls, heteroaromatics and heterocycles...
June 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/28586202/cytosine-iminyl-radical-cytn-%C3%A2-formation-via-electron-induced-debromination-of-5-bromocytosine-a-dft-and-gaussian-4-study
#12
Anil Kumar, Michael D Sevilla
Halogen-substituted pyrimidines, such as 5-bromouracil and 5-iodouracil, have been used as radio therapeutic (RT) agents in cancer treatment. The radiosensitizing activity of 5-bromouracil is attributed to its reaction with electron which produce the highly reactive uracil-5-yl radical by dissociating the C5-Br bond. Using density functional methods and highly accurate Gaussian 4 (G4) theory, herein, we show that 5-bromocytosine (5-Brcyt) after reaction with electron, also, leads to the formation of cytosine-5-yl radical...
June 29, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28585822/size-shape-and-phase-control-in-ultrathin-cdse-nanosheets
#13
Frauke Gerdes, Cristina Navío, Beatriz H Juárez, Christian Klinke
Ultrathin two-dimensional nanosheets raise a rapidly increasing interest due to their unique dimensionality-dependent properties. Most of the two-dimensional materials are obtained by exfoliation of layered bulk materials or are grown on substrates by vapor deposition methods. To produce free-standing nanosheets, solution-based colloidal methods are emerging as promising routes. In this work, we demonstrate ultrathin CdSe nanosheets with controllable size, shape, and phase. The key of our approach is the use of halogenated alkanes as additives in a hot-injection synthesis...
June 8, 2017: Nano Letters
https://www.readbyqxmd.com/read/28585445/lactose-esters-synthesis-and-biotechnological-applications
#14
Jakub Staroń, Janusz M Dąbrowski, Ewelina Cichoń, Maciej Guzik
Biodegradable nonionic sugar esters-based surfactants have been gaining more and more attention in recent years due to their chemical plasticity that enables the various applications of these molecules. In this review, various synthesis methods and biotechnological implications of lactose esters (LEs) uses are considered. Several chemical and enzymatic approaches are described for the synthesis of LEs, together with their applications, i.e. function in detergents formulation and as additives that not only stabilize food products but also protect food from undesired microbial contamination...
June 6, 2017: Critical Reviews in Biotechnology
https://www.readbyqxmd.com/read/28576279/-atypical-reaction-to-anesthesia-in-duchenne-becker-muscular-dystrophy
#15
Helga Cristina Almeida da Silva, Marcia Hiray, Mariz Vainzof, Beny Schmidt, Acary Souza Bulle Oliveira, José Luiz Gomes do Amaral
BACKGROUND AND OBJECTIVES: Duchenne/Becker muscular dystrophy affects skeletal muscles and leads to progressive muscle weakness and risk of atypical anesthetic reactions following exposure to succinylcholine or halogenated agents. The aim of this report is to describe the investigation and diagnosis of a patient with Becker muscular dystrophy and review the care required in anesthesia. CASE REPORT: Male patient, 14 years old, referred for hyperCKemia (chronic increase of serum creatine kinase levels - CK), with CK values of 7,779-29,040IU...
May 30, 2017: Revista Brasileira de Anestesiologia
https://www.readbyqxmd.com/read/28521262/rhodium-catalyzed-c-h-bond-activation-for-the-synthesis-of-quinonoid-compounds-significant-anti-trypanosoma-cruzi-activities-and-electrochemical-studies-of-functionalized-quinones
#16
Guilherme A M Jardim, Thaissa L Silva, Marilia O F Goulart, Carlos A de Simone, Juliana M C Barbosa, Kelly Salomão, Solange L de Castro, John F Bower, Eufrânio N da Silva Júnior
Thirty four halogen and selenium-containing quinones, synthesized by rhodium-catalyzed C-H bond activation and palladium-catalyzed cross-coupling reactions, were evaluated against bloodstream trypomastigotes of T. cruzi. We have identified fifteen compounds with IC50/24 h values of less than 2 μM. Electrochemical studies on A-ring functionalized naphthoquinones were also performed aiming to correlate redox properties with trypanocidal activity. For instance, (E)-5-styryl-1,4-naphthoquinone 59 and 5,8-diiodo-1,4-naphthoquinone 3, which are around fifty fold more active than the standard drug benznidazole, are potential derivatives for further investigation...
May 4, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28516256/-skin-diseases-associated-with-environmental-factors
#17
REVIEW
Vera Mahler
BACKGROUND: Multiple environmental exposures may derange the regulatory and repair mechanisms of the skin and lead to dermatological disease. OBJECTIVES: Provide an overview of non-allergic skin diseases associated with environmental factors. MATERIALS AND METHODS: Review of current scientific evidence for associations of non-allergic skin diseases with environmental exposures: irritation, chemicals, infection, UV-radiation, temperature. RESULTS: Predisposition (constitution e...
June 2017: Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz
https://www.readbyqxmd.com/read/28515440/a-highly-potent-class-of-halogenated-phenazine-antibacterial-and-biofilm-eradicating-agents-accessed-through-a-modular-wohl-aue-synthesis
#18
Hongfen Yang, Yasmeen Abouelhassan, Gena M Burch, Dimitris Kallifidas, Guangtao Huang, Hussain Yousaf, Shouguang Jin, Hendrik Luesch, Robert W Huigens
Unlike individual, free-floating planktonic bacteria, biofilms are surface-attached communities of slow- or non-replicating bacteria encased within a protective extracellular polymeric matrix enabling persistent bacterial populations to tolerate high concentrations of antimicrobials. Our current antibacterial arsenal is composed of growth-inhibiting agents that target rapidly-dividing planktonic bacteria but not metabolically dormant biofilm cells. We report the first modular synthesis of a library of 20 halogenated phenazines (HP), utilizing the Wohl-Aue reaction, that targets both planktonic and biofilm cells...
May 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28500969/oxidation-of-the-antibacterial-agent-norfloxacin-during-sodium-hypochlorite-disinfection-of-marine-culture-water
#19
Yuanyuan Zhang, Chuan Rong, Yanqun Song, Yinghui Wang, Jiying Pei, Xinying Tang, Ruijie Zhang, Kefu Yu
Chlorination disinfection and antibiotic addition are two universal processes of marine culture. The generation of disinfection byproducts (DBPs) is unavoidable. Antibiotic residue not only pollutes water but also acts as a precursor to the production of new DBPs. The fate of antibiotic norfloxacin (NOR) in chlorination disinfection was investigated. It was observed that NOR could be oxidized by disinfection agent sodium hypochlorite, but the oxidation rate varied considerably with the type of disinfected water...
May 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/28499825/induction-of-cytochrome-p450-dependent-mixed-function-oxidase-activities-and-peroxisome-proliferation-by-chloramine-t-in-male-rat-liver
#20
María-Aránzazu Martínez, Irma Ares, Jose-Luís Rodríguez, Marta Martínez, María-Rosa Martínez-Larrañaga, Arturo Anadón
Chloramine-T is an antimicrobial agent recognized for its disinfectant properties widely used in food industry. As an N-chloro-compound, chloramine-T contains electrophilic chlorine and in water it hydrolyses to hypochlorite. Chlorine as hypochlorous acid or hypochlorite is a very reactive chemical which can function as both an oxidant and halogenating agent. Because chloramine-T could be involved in the metabolic activation of drugs, in the present study the effects of chloramine-T on the activities of some drug metabolizing enzymes in rat liver microsomes and peroxisome proliferation were determined in vivo...
May 9, 2017: Food and Chemical Toxicology
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