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Sample records for benzyl radicals

  1. Growing up Radical: Investigation of Benzyl-Like Radicals with Increasing Chain Lengths

    Science.gov (United States)

    Korn, Joseph A.; Jawad, Khadija M.; Hewett, Daniel M.; Zwier, Timothy S.

    2015-06-01

    Combustion processes involve complex chemistry including pathways leading to polyaromatic hydrocarbons (PAHs) from small molecule precursors. Resonance stabilized radicals (RSRs) likely play an important role in the pathways to PAHs due to their unusual stability. Benzyl radical is a prototypical RSR that is stabilized by conjugation with the phenyl ring. Earlier work on α-methyl benzyl radical showed perturbations to the spectroscopy due to a hindered methyl rotor. If the alkyl chain is lengthened then multiple conformations become possible. This talk will discuss the jet-cooled spectroscopy of α-ethyl benzyl radical and α-propyl benzyl radical produced from the discharge of 1-phenyl propanol and 1-phenyl butanol respectively. Electronic spectra were obtained via resonant two-photon ionization, and IR spectra were obtained by resonant ion-dip infrared spectroscopy. Kidwell, N. M.; Reilly, N. J.; Nebgen, B.; Mehta-Hurt, D. N.; Hoehn, R. D.; Kokkin, D. L.; McCarthy, M. C.; Slipchenko, L. V.; Zwier, T. S. The Journal of Physical Chemistry A 2013, 117, 13465.

  2. Direct determination of rate constants for coupling between aromatic radical anions and alkyl and benzyl radicals by laser-flash photolysis

    DEFF Research Database (Denmark)

    Lund, T.; Christensen, P.; Wilbrandt, Robert Walter

    2003-01-01

    Coupling rates between the radicals methyl, n-, sec-, tert-butyl and benzyl (R-.) and the aromatic radical anions of 1,4-dicyanonaphthalene, 9,10-dicyanoanthracene and fluorenone (A(-.)) have been obtained using a new laser-flash photolysis method. The radicals R-. and the radical anions A(-.) were...... generated by a photoinduced electron transfer reaction between the aromatic compound A and the alkyl or benzyl triphenylborate anion RB(Ph)(3)(-). For the first time the rate constants of the coupling reaction between methyl and benzyl radicals with aromatic radical anions have been obtained. For all...... of the radicals and the structure and standard potentials of the aromatic radical anions....

  3. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical

    Science.gov (United States)

    Buckingham, Grant T.; Porterfield, Jessica P.; Kostko, Oleg; Troy, Tyler P.; Ahmed, Musahid; Robichaud, David J.; Nimlos, Mark R.; Daily, John W.; Ellison, G. Barney

    2016-07-01

    Cycloheptatrienyl (tropyl) radical, C7H7, was cleanly produced in the gas-phase, entrained in He or Ne carrier gas, and subjected to a set of flash-pyrolysis micro-reactors. The pyrolysis products resulting from C7H7 were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by infrared absorption spectroscopy. Pyrolysis pressures in the micro-reactor were roughly 200 Torr and residence times were approximately 100 μs. Thermal cracking of tropyl radical begins at 1100 K and the products from pyrolysis of C7H7 are only acetylene and cyclopentadienyl radicals. Tropyl radicals do not isomerize to benzyl radicals at reactor temperatures up to 1600 K. Heating samples of either cycloheptatriene or norbornadiene never produced tropyl (C7H7) radicals but rather only benzyl (C6H5CH2). The thermal decomposition of benzyl radicals has been reconsidered without participation of tropyl radicals. There are at least three distinct pathways for pyrolysis of benzyl radical: the Benson fragmentation, the methyl-phenyl radical, and the bridgehead norbornadienyl radical. These three pathways account for the majority of the products detected following pyrolysis of all of the isotopomers: C6H5CH2, C6H5CD2, C6D5CH2, and C6H513CH2. Analysis of the temperature dependence for the pyrolysis of the isotopic species (C6H5CD2, C6D5CH2, and C6H513CH2) suggests the Benson fragmentation and the norbornadienyl pathways open at reactor temperatures of 1300 K while the methyl-phenyl radical channel becomes active at slightly higher temperatures (1500 K).

  4. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Buckingham, Grant T. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA; National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Porterfield, Jessica P. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA; Kostko, Oleg [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Troy, Tyler P. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Ahmed, Musahid [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Robichaud, David J. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Nimlos, Mark R. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Daily, John W. [Department of Mechanical Engineering, Center for Combustion and Environmental Research, University of Colorado, Boulder, Colorado 80309-0427, USA; Ellison, G. Barney [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA

    2016-07-05

    Cycloheptatrienyl (tropyl) radical, C7H7, was cleanly produced in the gas-phase, entrained in He or Ne carrier gas, and subjected to a set of flash-pyrolysis micro-reactors. The pyrolysis products resulting from C7H7 were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by infrared absorption spectroscopy. Pyrolysis pressures in the micro-reactor were roughly 200 Torr and residence times were approximately 100 us. Thermal cracking of tropyl radical begins at 1100 K and the products from pyrolysis of C7H7 are only acetylene and cyclopentadienyl radicals. Tropyl radicals do not isomerize to benzyl radicals at reactor temperatures up to 1600 K. Heating samples of either cycloheptatriene or norbornadiene never produced tropyl (C7H7) radicals but rather only benzyl (C6H5CH2). The thermal decomposition of benzyl radicals has been reconsidered without participation of tropyl radicals. There are at least three distinct pathways for pyrolysis of benzyl radical: the Benson fragmentation, the methyl-phenyl radical, and the bridgehead norbornadienyl radical. These three pathways account for the majority of the products detected following pyrolysis of all of the isotopomers: C6H5CH2, C6H5CD2, C6D5CH2, and C6H5 13CH2. Analysis of the temperature dependence for the pyrolysis of the isotopic species (C6H5CD2, C6D5CH2, and C6H5 13CH2) suggests the Benson fragmentation and the norbornadienyl pathways open at reactor temperatures of 1300 K while the methyl-phenyl radical channel becomes active at slightly higher temperatures (1500 K).

  5. Temperature dependence of the lifetime of excited benzyl and other arymethyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    Miesel, D.; Das, P.K.; Hug, G.L.; Bhattacharyya, K.; Fessenden, R.W.

    1986-08-06

    The temperature dependence of the fluorescence lifetime of benzyl, benzyl-d/sub 7/, ..cap alpha..-methylbenzyl, and triphenylmethyl radicals has been studied in 2-methyltetrahydroduran from 77 to 300 K. Temperature independent and unusual temperature dependent relaxation pathways are observed for the excited states of all four radicals. Activation energies for the temperature-dependent relaxation process are approx.1400 cm/sup -1/ for all these radicals, and frequency factors are in the range of (2-20) x 10/sup 11/ s/sup -1/. For Ph/sub 3/C radicals, the temperature-dependent process leads to observable photochemistry. However, no photochemistry is observed to result from the thermally activated relaxation of benzyl radicals. Possible pathways of these nonradiative decay processes are discussed and contrasted with the weak temperature dependence for the relaxation of diphenylmethyl radicals. It is proposed that the temperature-dependent route for the radiationless decay of benzyl radicals results from differential vibronic mixing of the two excited states, the 1/sup 2/A/sub 2/ and 2/sup 2/B/sub 2/ states. Most efficient in that mixing seems to be C-C stretching vibrational modes.

  6. Thermal Decomposition of C7H7 Radicals; Benzyl, Tropyl, and Norbornadienyl

    Science.gov (United States)

    Buckingham, Grant; Ellison, Barney; Daily, John W.; Ahmed, Musahid

    2015-06-01

    Benzyl radical (C6H5CH2) and two other C7H7 radicals are commonly encountered in the combustion of substituted aromatic compounds found in biofuels and gasoline. High temperature pyrolysis of benzyl radical requires isomerization to other C7H7 radicals that may include cycloheptatrienyl (tropyl) radical (cyc-C7H7) and norbornadienyl radical. The thermal decomposition of all three radicals has now been investigated using a micro-reactor that heats dilute gas-phase samples up to 1600 K and has a residence time of about 100 μ-sec. The pyrolysis products exit the reactor into a supersonic expansion and are detected using synchrotron-based photoionization mass spectrometry and matrix-isolation IR spectroscopy. The products of the pyrolysis of benzyl radical (C6H5CH2) along with three isotopomers (C6H513CH2, C6D5CH2, and C6H5CD2) were detected and identified. The distribution of 13C atoms and D atoms indicate that multiple different decomposition pathways are active. Buckingham, G. T., Ormond, T. K., Porterfield, J. P., Hemberger, P., Kostko, O., Ahmed, M., Robichaud, D. J., Nimlos, M. R., Daily, J. W., Ellison, G. B. 2015, Journal of Chemical Physics 142 044307

  7. Polycyclic aromatic hydrocarbon (PAH) formation from benzyl radicals: a reaction kinetics study.

    Science.gov (United States)

    Sinha, Sourab; Raj, Abhijeet

    2016-03-21

    The role of resonantly stabilized radicals such as propargyl, cyclopentadienyl and benzyl in the formation of aromatic hydrocarbons such as benzene and naphthalene in the high temperature environments has been long known. In this work, the possibility of benzyl recombination to form three-ring aromatics, phenanthrene and anthracene, is explored. A reaction mechanism for it is developed, where reaction energetics are calculated using density functional theory (B3LYP functional with 6-311++G(d,p) basis set) and CBS-QB3, while temperature-dependent reaction kinetics are evaluated using transition state theory. The mechanism begins with barrierless formation of bibenzyl from two benzyl radicals with the release of 283.2 kJ mol(-1) of reaction energy. The further reactions involve H-abstraction by a H atom, H-desorption, H-migration, and ring closure to gain aromaticity. Through mechanism and rate of production analyses, the important reactions leading to phenanthrene and anthracene formation are determined. Phenanthrene is found to be the major product at high temperatures. Premixed laminar flame simulations are carried out by including the proposed reactions for phenanthrene formation from benzyl radicals and compared to experimentally observed species profiles to understand their effects on species concentrations.

  8. Gas-phase synthesis of the benzyl radical (C(6)H(5)CH(2)).

    Science.gov (United States)

    Dangi, Beni B; Parker, Dorian S N; Yang, Tao; Kaiser, Ralf I; Mebel, Alexander M

    2014-04-25

    Dicarbon (C2 ), the simplest bare carbon molecule, is ubiquitous in the interstellar medium and in combustion flames. A gas-phase synthesis is presented of the benzyl radical (C6 H5 CH2 ) by the crossed molecular beam reaction of dicarbon, C2 (X(1) Σg (+) , a(3) Πu ), with 2-methyl-1,3-butadiene (isoprene; C5 H8 ; X(1) A') accessing the triplet and singlet C7 H8 potential energy surfaces (PESs) under single collision conditions. The experimental data combined with ab initio and statistical calculations reveal the underlying reaction mechanism and chemical dynamics. On the singlet and triplet surfaces, the reactions involve indirect scattering dynamics and are initiated by the barrierless addition of dicarbon to the carbon-carbon double bond of the 2-methyl-1,3-butadiene molecule. These initial addition complexes rearrange via multiple isomerization steps, leading eventually to the formation of C7 H7 radical species through atomic hydrogen elimination. The benzyl radical (C6 H5 CH2 ), the thermodynamically most stable C7 H7 isomer, is determined as the major product.

  9. Conformation-specific spectroscopy of alkyl benzyl radicals: Effects of a radical center on the CH stretch infrared spectrum of an alkyl chain

    Science.gov (United States)

    Korn, Joseph A.; Tabor, Daniel P.; Sibert, Edwin L.; Zwier, Timothy S.

    2016-09-01

    An important initial step in the combustion of gasoline and diesel fuels is the abstraction of hydrogen from alkylbenzenes to form resonance-stabilized alkyl benzyl radicals. This work uses, for the first time, double resonance spectroscopy methods to explore the conformation-specific vibronic and infrared spectroscopy of the α-ethylbenzyl (αEtBz) and α-propylbenzyl (αPrBz) radicals. Local mode Hamiltonian modeling enables assignment of the alkyl CH stretch IR spectra, accounting for Fermi resonance that complicates aliphatic alkyl CH stretch IR spectroscopy. The ground state conformational preferences of the ethyl and propyl chains are changed from those in the alkylbenzenes themselves, with global minima occurring for an in-plane orientation of the alkyl chain (trans) about its first dihedral angle (ϕf123, numbers are alkyl C atoms. C1 is CH radical site). This in-plane structure is the only observed conformer for the α-EtBz radical, while two conformers, tt and tg' share this orientation at the first dihedral, but differ in the second (ϕ1234) for the αPrBz radical. The in-plane orientation lowers the local site frequencies of the CH2 group stretches immediately adjacent to the benzylic radical site by about 50 cm-1 relative to those in pure alkyl chains or alkylbenzenes. This effect of the radical site is localized on the first CH2 group, with little effect on subsequent members of the alkyl chain. In the D1 excited electronic state, an out-of-plane orientation is preferred for the alkyl chains, leading to torsional mode Franck-Condon activity in the D0-D1 spectra that is both conformer-specific and diagnostic of the conformational change.

  10. Reactivity and acid-base behavior of ring-methoxylated arylalkanoic acid radical cations and radical zwitterions in aqueous solution. Influence of structural effects and pH on the benzylic C-H deprotonation pathway.

    Science.gov (United States)

    Bietti, Massimo; Capone, Alberto

    2006-07-07

    A product and time-resolved kinetic study of the one-electron oxidation of ring-methoxylated phenylpropanoic and phenylbutanoic acids (Ar(CH2)nCO2H, n = 2, 3) has been carried out at different pH values. Oxidation leads to the formation of aromatic radical cations (Ar.+(CH2)nCO2H) or radical zwitterions (Ar.+(CH2)nCO2-) depending on pH, and pKa values for the corresponding acid-base equilibria have been measured. In the radical cation, the acidity of the carboxylic proton decreases by increasing the number of methoxy ring substituents and by increasing the distance between the carboxylic group and the aromatic ring. At pH 1.7 or 6.7, the radical cations or radical zwitterions undergo benzylic C-H deprotonation as the exclusive side-chain fragmentation pathway, as clearly shown by product analysis results. At pH 1.7, the first-order deprotonation rate constants measured for the ring-methoxylated arylalkanoic acid radical cations are similar to those measured previously in acidic aqueous solution for the alpha-C-H deprotonation of structurally related ring-methoxylated alkylaromatic radical cations. In basic solution, the second-order rate constants for reaction of the radical zwitterions with (-)OH (k-OH)) have been obtained. These values are similar to those obtained previously for the (-)OH-induced alpha-C-H deprotonation of structurally related ring-methoxylated alkylaromatic radical cations, indicating that under these conditions the radical zwitterions undergo benzylic C-H deprotonation. Very interestingly, with 3,4-dimethoxyphenylethanoic acid radical zwitterion, that was previously observed to undergo exclusive decarboxylation up to pH 10, competition between decarboxylation and benzylic C-H deprotonation is observed above pH 11.

  11. ESR and ring inversion of tetralin-1-yl and ESR of related benzyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    Conradi, M.S.; Zeldes, H.; Livingston, R.

    1979-03-08

    The tetralin-1-yl radical 1 was generated in solution by hydrogen abstraction from tetralin by photoexcited benzophenone. The proton hyperfine splittings and the g value are reported from -69 to 146/sup 0/C. An alternating line width effect occurs and is ascribed to ring inversion in the saturated portion of the radical. Line widths and amplitudes were analyzed at low and high inversion rates (near -50 and 130/sup 0/C, respectively) to yield values of the ring inversion rate. Arhenius parameters for the inversion are E = 30 kJ/mol +- 12% and log k = 13.1 +- 0.7. Two azimuthal angles which indicate the extent of ring puckering are determined from the proton splittings at -69/sup 0/C. The room temperature hyperfine constants and g values of m- and o-xylyl and ..cap alpha..-methylbenzyl are reported and support the assignment of proton splittings in tetralin-1-yl. The methyl group splittings in m- and o-xylol are smaller than expected from comparison with related radicals. 3 figures, 3 tables.

  12. Reaction rates at 297 {plus_minus} 3 K of four benzyl type radicals with O{sub 2}, NO, and NO{sub 2} by discharge flow/laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Goumri, A.; Elmaimouni, L.; Sawerysyn, J.P.; Devolder, P. [Universite des Sciences et Techniques, Villeneuve D`Ascq (France)

    1992-06-25

    The rate constants of 4 benzyl type radicals with O{sub 2}, NO, and NO{sub 2} are measured by discharge flow/laser-induced fluorescence. The ratio of these rate constants with NO and O{sub 2} indicates that tropospheric o- and m-methylbenzyl radicals are scavenged by O{sub 2}. 50 refs., 5 figs., 4 tabs.

  13. Living/controlled free radical copolymerization of chlorotrifluoroethene and butyl vinyl ether under 60Co γ-ray irradiation in the presence of S-benzyl O-ethyl dithiocarbonate.

    Science.gov (United States)

    Liu, Lei; Lu, Dan; Wang, Hu; Dong, Qibao; Wang, Pucheng; Bai, Ruke

    2011-07-21

    Living/controlled free radical copolymerization of chlorotrifluoroethene and butyl vinyl ether has been successfully achieved at room temperature under (60)Co γ-ray irradiation in the presence of S-benzyl O-ethyl dithiocarbonate. The alternating and block copolymers have been obtained with well-defined molecular weights and narrow molecular weight distributions.

  14. Jet-Cooled Excitation Spectra of Large Benzannulated Benzyl Radicals: 9-ANTHRACENYLMETHYL (C_{15}H_{11}) and 1-PYRENYLMETHYL (C_{17}H_{11})

    Science.gov (United States)

    O'Connor, Gerard D.; Bacskay, George B.; Woodhouse, Gabrielle V. G.; Troy, Tyler P.; Nauta, Klaas; Kable, Scott H.; Schmidt, Timothy W.

    2013-06-01

    The jet-cooled D_1 ← D_0 excitation spectra of two benzannulated benzyl radicals (BBRs), 9-anthracenylmethyl (9-AnMe) and 1-pyrenylmethyl (9-PyMe), have been obtained using mass-resolved resonant two-colour two-photon ionization spectroscopy (R2C2PI). Analysis of the spectra in view of symmetry and calculated vibrational frequencies indicate significant vibronic coupling. From the spectrum of 9-AnMe we elucidate significant anharmonicity in the excited state. This anharmonic behaviour is examined computationally through both TDDFT and ab initio methods. Excited state properties of 9-AnMe and 1-PyMe are examined with reference to the existing spectra of smaller BBRs. Trends in the observed spectra of BBRs allow spectroscopic properties of larger BBRs to be predicted. These predictions suggest the D_1 ← D_0 transitions of large BBRs are unlikely to be carriers of the diffuse interstellar bands.

  15. Antimicrobial, free radical scavenging activities and catalytic oxidation of benzyl alcohol by nano-silver synthesized from the leaf extract of Aristolochia indica L.: a promenade towards sustainability

    Science.gov (United States)

    Shanmugam, C.; Sivasubramanian, G.; Parthasarathi, Bera; Baskaran, K.; Balachander, R.; Parameswaran, V. R.

    2016-06-01

    Silver nanoparticles (Ag-NPs) were synthesized from aqueous silver nitrate through a simple route using the leaf extract of Aristolochia indica L. (LAIL) which acted as a reducing as well as capping agent. X-ray diffraction confirmed that the synthesized silver particles have a face centred cubic structure. EDS predicted the presence of elemental silver. The SEM images showed the synthesis of spherically mono-dispersed particles, with nano dimensions accounted by the TEM images. Infra-red spectrum adopted to the different organic functionalities present at the surface of the particles. TGA indicated an overall 11 % weight loss up to 1000 °C, suggesting desorption of biomolecules from the surface. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of metallic silver nanoparticles. The prepared material was utilized as catalyst in the oxidation of benzyl alcohol with molecular oxygen as the oxidant in methanol, under ambient conditions of temperature and pressure. Also Ag-NPs showed good to moderate anti-microbial activity employing the Agar disc diffusion method against various strains using Ciprofloxacin and Fluconazole as standard. Free radical scavenging activity of the nanoparticles were observed by modified 1,1-diphynyl-2-picrylhydrazyl, DPPH and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS in vitro assays. The work presented here demonstrates the adaptability of the synthesized Ag-NPs in participating as a disinfectant agent, free radical scavenger and an effective oxidation catalyst. The basic premise of attaining sustainability through the green synthesis of smart multifaceted materials has been consciously addressed.

  16. Benzyl Alcohol Topical

    Science.gov (United States)

    Benzyl alcohol lotion is used to treat head lice (small insects that attach themselves to the skin) in adults ... children less than 6 months of age. Benzyl alcohol is in a class of medications called pediculicides. ...

  17. Single Pot Benzylation of O-Xylene with Benzyl Chloride and Benzyl Alcohol Over Pillared Montmorillonites

    Directory of Open Access Journals (Sweden)

    Kurian Manju

    2014-09-01

    Full Text Available Improvement of product selectivity is a major concern of the day. Presence of a coreactant can alter the rate as well as product selectivity of many key reactions like Friedel-Crafts benzylation. Single pot benzylation of o-xylene with benzyl chloride and benzyl alcohol was studied over transition metal exchanged pillared clay catalysts. Complete conversion of benzyl alcohol occured within one hour with 100% monoalkylated product selectivity. The reaction of o-xylene with benzyl alcohol was found to proceed fast in presence of benzyl chloride in single pot, than when present alone as the benzylating species. This enhancement occurs at the expense of no reaction of benzyl chloride, which when present alone reacts faster than benzyl alcohol. Existence of a second transition metal exchanged between the pillars increased the rate of the reaction. A detailed investigation of the reaction variables suggested preferential adsorption of benzyl alcohol to catalyst active sites as the reason.

  18. Benzyl 2-((E-Tosyliminomethylphenylcarbamate

    Directory of Open Access Journals (Sweden)

    Kwang Min Ko

    2016-10-01

    Full Text Available Benzyl 2-((E-tosyliminomethylpenylcarbamate was prepared in good yield and characterized by the condensation reaction of benzyl 2-formylphenylcarbamate with p-toluenesulfonyl amine. The structure of the newly synthesized compound was determined using 1H, 13C-NMR, IR and mass spectral data.

  19. Radical substitution with azide

    DEFF Research Database (Denmark)

    Pedersen, Christian Marcus; Marinescu, Lavinia Georgeta; Bols, Mikael

    2005-01-01

    and the substrate. A primary deuterium kinetic isotope effect was found for the azidonation of benzyl ethers both with TMSN3-PhI(OAc)2 and with IN3. Also a Hammett free energy relationship study of this reaction showed good correlation with sigma+ constants giving with rho-values of -0.47 for TMSN3-PhI(OAc)2 and -0.......39 for IN3. On this basis a radical mechanism of the reaction was proposed....

  20. Benzylation of Aromatic Compounds with Benzyl Chloride Catalyzed by Nafion/SiO2 Nanocomposite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Kun Guo YANG; Rui Mao HUA; Hai WANG; Bo Qing XU1

    2005-01-01

    In the presence of Nafion/SiO2 nanocomposite catalyst, the benzylation of aromatic compounds with benzyl chloride proceeded to afford diphenylmethane derivatives in high yields.The catalyst showed high catalytic activity not only for electron-rich aromatic compounds, but also for electron-poor aromatic compounds. Under identical conditions, the self-benzylation of benzyl chloride, and dibenzylation and/or multi-benzylation of aromatic compounds were negligible.

  1. Determination of NO chemical affinities of benzyl nitrite in acetonitrile

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Xiaoqing ZHU; Jinpei CHENG

    2008-01-01

    There is an increasing interest in the study of NO chemical affinities of organic nitrites, for the bio-logical and physiological effects of organic nitrites seem to be due to their ability to release NO. In this paper, NO chemical affinities of ten substituted benzyl nitrites were determined by titration calorimetry combined with a ther-modynamic cycle in acetonitrile solution. The results show that ΔHhet(O-NO)s of benzyl nitrites are substan-tially larger than the corresponding ΔHhomo(O-NO)s, suggesting that these O-nitroso compounds much more easily release NO radicals by the O-NO bond homolytic cleavage. It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.

  2. I2-Mediated 2H-indazole synthesis via halogen-bond-assisted benzyl C-H functionalization.

    Science.gov (United States)

    Yi, Xiangli; Jiao, Lei; Xi, Chanjuan

    2016-10-18

    I2-Mediated benzyl C-H functionalization has been developed for the synthesis of 2H-indazoles, which features high efficiency, simple conditions and no need for metals. Mechanistic experiments and DFT calculations have revealed halogen bond assistance and a radical chain process for this reaction. The azo group and the bound iodine cooperate in the hydrogen abstraction step, which circumvents the thermodynamic disfavor of direct hydrogen abstraction by a simple iodine radical.

  3. Kinetics of the benzyl + O(3P) reaction: a quantum chemical/statistical reaction rate theory study.

    Science.gov (United States)

    da Silva, Gabriel; Bozzelli, Joseph W

    2012-12-14

    The resonance stabilized benzyl radical is an important intermediate in the combustion of aromatic hydrocarbons and in polycyclic aromatic hydrocarbon (PAH) formation in flames. Despite being a free radical, benzyl is relatively stable in thermal, oxidizing environments, and is predominantly removed through bimolecular reactions with open-shell species other than O(2). In this study the reaction of benzyl with ground-state atomic oxygen, O((3)P), is examined using quantum chemistry and statistical reaction rate theory. C(7)H(7)O energy surfaces are generated at the G3SX level, and include several novel pathways. Transition state theory is used to describe elementary reaction kinetics, with canonical variational transition state theory applied for barrierless O atom association with benzyl. Apparent rate constants and branching ratios to different product sets are obtained as a function of temperature and pressure from solving the time-dependent master equation, with RRKM theory for microcanonical k(E). These simulations indicate that the benzyl + O reaction predominantly forms the phenyl radical (C(6)H(5)) plus formaldehyde (HCHO), with lesser quantities of the C(7)H(6)O products benzaldehyde, ortho-quinone methide, and para-quinone methide (+H), along with minor amounts of the formyl radical (HCO) + benzene. Addition of O((3)P) to the methylene site in benzyl produces a highly vibrationally excited C(7)H(7)O* adduct, the benzoxyl radical, which can β-scission to benzaldehyde + H and phenyl + HCHO. In order to account for the experimental observation of benzene as the major reaction product, a roaming radical mechanism is proposed that converts the nascent products phenyl and HCHO to benzene + HCO. Oxygen atom addition at the ortho and para ring sites in benzyl, which has not been previously considered, is shown to lead to the quinone methides + H; these species are less-stable isomers of benzaldehyde that are proposed as important combustion intermediates, but

  4. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  5. Antioxidant activity of the new thiosulfinate derivative, S-benzyl phenylmethanethiosulfinate, from Petiveria alliacea L.

    Science.gov (United States)

    Okada, Youji; Tanaka, Kaoru; Sato, Eisuke; Okajima, Haruo

    2008-03-21

    The antioxidant effects of the new thiosulfinate derivative, S-benzyl phenylmethanethiosulfinate (BPT), against the oxidation of cumene and methyl linoleate (ML) in chlorobenzene were studied in detail using HPLC. The results showed that BPT provided effective inhibition with a well-defined induction period under these oxidation conditions, and it was found that the stoichiometric factor (n), the number of peroxyl radicals trapped by one antioxidant molecule, of BPT is about 2. We then undertook a thorough investigation aimed at elucidating the active structural site of BPT. Various model compounds, such as diphenyl disulfide, dibenzyl disulfide, S-phenyl benzenethiosulfinate and S-ethyl phenylmethanethiosulfinate, were used which provided evidence that the benzylic hydrogen of BPT is mainly associated with the peroxyl radical scavenging. Moreover, we measured the rate constant for the reaction of BPT with peroxyl radicals derived from cumene and ML in chlorobenzene, and based on these measurements, BPT reacts with these peroxyl radicals with a rate constant of k(inh) = 8.6 x 10(3) and 6.2 x 10(4) M(-1) s(-1), respectively.

  6. Origin of the SN2 benzylic effect.

    Science.gov (United States)

    Galabov, Boris; Nikolova, Valia; Wilke, Jeremiah J; Schaefer, Henry F; Allen, Wesley D

    2008-07-30

    The S N2 identity exchange reactions of the fluoride ion with benzyl fluoride and 10 para-substituted derivatives (RC6H 4CH 2F, R = CH3, OH, OCH 3, NH2, F, Cl, CCH, CN, COF, and NO2) have been investigated by both rigorous ab initio methods and carefully calibrated density functional theory. Groundbreaking focal-point computations were executed for the C6H5CH 2F + F (-) and C 6H 5CH2Cl + Cl (-) SN2 reactions at the highest possible levels of electronic structure theory, employing complete basis set (CBS) extrapolations of aug-cc-pV XZ (X = 2-5) Hartree-Fock and MP2 energies, and including higher-order electron correlation via CCSD/aug-cc-pVQZ and CCSD(T)/aug-cc-pVTZ coupled cluster wave functions. Strong linear dependences are found between the computed electrostatic potential at the reaction-center carbon atom and the effective SN2 activation energies within the series of para-substituted benzyl fluorides. An activation strain energy decomposition indicates that the SN2 reactivity of these benzylic compounds is governed by the intrinsic electrostatic interaction between the reacting fragments. The delocalization of nucleophilic charge into the aromatic ring in the SN2 transition states is quite limited and should not be considered the origin of benzylic acceleration of SN2 reactions. Our rigorous focal-point computations validate the benzylic effect by establishing SN2 barriers for (F (-), Cl (-)) identity exchange in (C6H5CH2F, C6H 5CH2Cl) that are lower than those of (CH3F, CH3Cl) by (3.8, 1.6) kcal mol (-1), in order.

  7. Polydopamine-Coated TiO2 Nanotubes for Selective Photocatalytic Oxidation of Benzyl Alcohol to Benzaldehyde Under Visible Light.

    Science.gov (United States)

    Tripathy, Jyotsna; Loget, Gabriel; Altomare, Marco; Schmuki, Patrik

    2016-05-01

    TiO2 nanotube arrays grown by anodization were coated with thin layers of polydopamine as visible light sensitizer. The PDA-coated TiO2 scaffolds were used as photocatalyst for selective oxidation of benzyl alcohol under monochromatic irradiation at 473 nm. Benzaldehyde was selectively formed and no by-products could be detected. A maximized reaction yield was obtained in O2-saturated acetonitrile. A mechanism is proposed that implies firstly the charge carrier generation in polydopamine as a consequence of visible light absorption. Secondly, photo-promoted electrons are injected in TiO2 conduction band, and subsequently transferred to dissolved O2 to form O*2- radicals. These radicals react with benzyl alcohol and lead to its selective dehydrogenation oxidation towards benzaldehyde.

  8. Oxidation of N-benzyl groups

    Institute of Scientific and Technical Information of China (English)

    QIU, Wen-Ge; CHEN, Shu-Sen; YU, Yong-Zhong

    2000-01-01

    The oxidative reactivity of 2,6,8, 12-tetraacetyl-4, 10- dibenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,9. 03,11] dodecane (3) in several conditions was studied. It was found that the N-benzyl groups in compound 3 could be oxidized to benzoyl groups byCr(Ⅳ) reagents, and could be removed by cerium ammonium nitrate (CAN), meanwhile nttroamine prooducts were given.

  9. Structure and properties of poly(benzyl acrylate) synthesized under microwave energy

    Energy Technology Data Exchange (ETDEWEB)

    Oberti, Tamara G. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET Casilla de Correo 16, Sucursal 4, 1900 La Plata (Argentina); Laboratorio de Estudio de Compuestos Organicos (LADECOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Schiavoni, M. Mercedes [Laboratorio de Estudio de Compuestos Organicos (LADECOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Cortizo, M. Susana [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET Casilla de Correo 16, Sucursal 4, 1900 La Plata (Argentina)], E-mail: gcortizo@inifta.unlp.edu.ar

    2008-05-15

    Benzyl acrylate was polymerized under microwave irradiation using radical initiation (benzoyl peroxide, BP). The effect of the concentration of BP and power irradiation on the conversion, average molecular weights and the polydispersity index (M{sub w}/M{sub n}) were investigated. The {sup 1}H NMR and {sup 13}C NMR spectra analysis showed tendency to syndiotacticity and branched polymers were obtained at high conversion of reactions. A significant enhancement of the rates of polymerization and similar thermodynamic behavior, as compared with those obtained under thermal conditions was found.

  10. Synthesis of benzyl cinnamate by enzymatic esterification of cinnamic acid.

    Science.gov (United States)

    Wang, Yun; Zhang, Dong-Hao; Chen, Na; Zhi, Gao-Ying

    2015-12-01

    In this study, lipase catalysis was successfully applied in synthesis of benzyl cinnamate through esterification of cinnamic acid with benzyl alcohol. Lipozyme TLIM was found to be more efficient for catalyzing this reaction than Novozym 435. In order to increase the yield of benzyl cinnamate, several media, including acetone, trichloromethane, methylbenzene, and isooctane, were used in this reaction. The reaction showed a high yield using isooctane as medium. Furthermore, the effects of several parameters such as water activity, reaction temperature, etc, on this reaction were analyzed. It was pointed out that too much benzyl alcohol would inhibit lipase activity. Under the optimum conditions, lipase-catalyzed synthesis of benzyl cinnamate gave a maximum yield of 97.3%. Besides, reusable experiment of enzyme demonstrated that Lipozyme TLIM retained 63% of its initial activity after three cycles. These results were of general interest for developing industrial processes for the preparation of benzyl cinnamate.

  11. Benzylic oxidation catalyzed by dirhodium(II,III) caprolactamate.

    Science.gov (United States)

    Catino, Arthur J; Nichols, Jason M; Choi, Hojae; Gottipamula, Sidhartha; Doyle, Michael P

    2005-11-10

    [reaction: see text] Dirhodium caprolactamate [Rh2(cap)4] is an effective catalyst for benzylic oxidation with tert-butyl hydroperoxide (TBHP) under mild conditions. Sodium bicarbonate is the optimal base additive for substrate conversion. Benzylic carbonyl compounds are readily obtained, and a formal synthesis of palmarumycin CP2 using this methodology is described.

  12. Whole cells in enantioselective reduction of benzyl acetoacetate

    Directory of Open Access Journals (Sweden)

    Joyce Benzaquem Ribeiro

    2014-09-01

    Full Text Available The β-ketoester benzyl acetoacetate was enantioselectively reduced to benzyl (S-3-hydroxybutanoate by seven microorganism species. The best result using free cells was obtained with the yeast Hansenula sp., which furnished 97% ee and 85% of conversion within 24 h. After immobilization in calcium alginate spheres, K.marxianus showed to be more stable after 2 cycles of reaction.

  13. Highly Selective Liquid-Phase Benzylation of Anisole with Solid-Acid Zeolite Catalysts

    DEFF Research Database (Denmark)

    Poreddy, Raju; Shunmugavel, Saravanamurugan; Riisager, Anders

    2015-01-01

    Zeolites were evaluated as solid acid catalysts for the liquid-phase benzylation of anisole with benzyl alcohol, benzyl bromide, and benzyl chloride at 80 °C. Among the examined zeolites, H-mordenite-10 (H-MOR-10) demonstrated particular high activity (>99 %) and excellent selectivity (>96...

  14. Enhanced catalytic properties of mesoporous mordenite for benzylation of benzene with benzyl alcohol

    Science.gov (United States)

    Saxena, Sandeep K.; Viswanadham, Nagabhatla

    2017-01-01

    Zeolite mordenite has been treated with nitric acid at different severities so as to facilitate the framework dealumination and optimization of the textural properties such as acidity and porosity. The samples obtained have been characterized by X-ray diffraction, FTIR, SEM, TEM, surface area, porosity by N2 adsorption and ammonia TPD. The resultant samples have been evaluated towards the bulky alkylation reaction of benzylation of benzene with benzyl alcohol. The studies indicated the improvement in the textural properties such as surface area, pore volume and acidity of the samples after the acid treatment. While, the phenomenon of enhancement in properties was exhibited by all the acid treated mordenite samples, the highest improvement in properties was observed at a particular condition of acid treatment (SM-2 sample). This particular sample also exhibited highest acidity and the presence of ∼10 nm size pores that resulted in the effective catalytic activity towards the bulky alkylation reaction of benzene with benzyl alcohol to produce high yields of di-phenyl methane.

  15. Benzyl (E-3-(2-methylbenzylidenedithiocarbazate

    Directory of Open Access Journals (Sweden)

    Shang Shan

    2011-09-01

    Full Text Available The title compound, C16H16N2S2, was obtained from the condensation reaction of benzyl dithiocarbazate and 2-methylbenzaldehyde. The asymmetric unit contains two independent molecules. In both molecules, the methylphenyl ring and the dithiocarbazate fragment are located on opposite sides of the C=N bond, showing an E conformation. In each molecule, the dithiocarbazate fragment is approximately planar, the r.m.s deviations being 0.018 and 0.025 Å. The mean plane of dithiocarbazate group is oriented at dihedral angles of 7.9 (3 and 68.24 (12°, respectively, to the methylphenyl and phenyl rings in one molecule, while the corresponding angles in the other molecule are 10.9 (3 and 69.76 (16°. Intermolecular N—H...S hydrogen bonding occurs in the crystal structure to generate inversion dimers for both molecules.

  16. Palladium-catalyzed α-arylation of benzylic phosphine oxides.

    Science.gov (United States)

    Montel, Sonia; Jia, Tiezheng; Walsh, Patrick J

    2014-01-03

    A novel approach to prepare diarylmethyl phosphine oxides from benzyl phosphine oxides via deprotonative cross-coupling processes (DCCP) is reported. The optimization of the reaction was guided by High-Throughput Experimentation (HTE) techniques. The Pd(OAc)2/Xantphos-based catalyst enabled the reaction between benzyl diphenyl or dicyclohexyl phosphine oxide derivatives and aryl bromides in good to excellent yields (51-91%).

  17. First Magnesium-mediated Carbonyl Benzylation in Water

    Institute of Scientific and Technical Information of China (English)

    DENG,Wei(邓维); TAN,Xiang-Hui(谭翔辉); LIU,Lei(刘磊); GUO,Qing-Xiang(郭庆祥)

    2004-01-01

    Catalyzed by AgNO3, Mg was found for the first time to be able to mediate the coupling reaction between aromatic aldehydes and benzyl bromide or chloride in water. The yields were slightly higher than the recent results for Mg-mediated allylation despite the fact that aqueous benzylation is intrinsically much harder than allylation. It was also found that the coupling reaction was chemoselective for aromatic aldehydes over aliphatic aldehydes, and chemoselective for aromatic aldehydes over aromatic ketones.

  18. Benzylation of Toluene over Iron Modified Mesoporous Ceria

    Directory of Open Access Journals (Sweden)

    K.J. Rose Philo

    2012-12-01

    Full Text Available Green chemistry has been looked upon as a sustainable science which accomplishes both economical and environmental goals, simultaneously.With this objective, we developed an alternative process to obtain the industrially important benzyl aromatics by benzylation of aromatics using benzyl chloride, catalysed by mesoporous solid acid catalysts. In this work mesoporous ceria is prepared using neutral surfactant which helped the calcination possible at a lower temperature enabling a higher surface area. Mesoporous ceria modified with Fe can be successfully utilized for the selective benzylation of toluene to more desirable product methyl diphenyl methane with 100% conversion and selectivity in 2 hours using only 50mg of the catalyst under milder condition. The reusability, regenerability, high selectivity, 100% conversion, moderate reaction temperature and absence of solvent, etc. make these catalysts to be used in a truly heterogeneous manner and make the benzylation reaction an environment friendly one. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 30th June 2012; Revised: 7th November 2012; Accepted: 10th November 2012[How to Cite: K.J. Rose Philo, S. Sugunan. (2012. Benzylation of Toluene over Iron Modified Mesoporouxs Ceria. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 158-164. (doi:10.9767/bcrec.7.2.3759.158-164][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3759.158-164 ] | View in 

  19. Embryolethality of butyl benzyl phthalate in rats

    Energy Technology Data Exchange (ETDEWEB)

    Ema, N.; Itami, T.; Kawasaki, H. (National Inst. Hyg. Science, Osaka (Japan))

    1991-03-15

    The developmental toxicity of butyl benzyl phthalate (BBP) was studied in Wistar rats. Pregnant rats were given BBP at a dosage of 0, 0.25, 0.5, 1.0 or 2.0% in the diet from day 0 to day 20 of pregnancy. Morphological examinations of the fetuses revealed no evidence of teratogenesis. In the 2.0% group, all dams exhibited complete resorption of all the implanted embryos, and their food consumption, body weight gain and adjusted weight gain during pregnancy were markedly lowered. To determine whether the embryolethality was the result of reduced food consumption during pregnancy, a pair-feeding study was performed in which the pregnant rats received the same amount of diet consumed by the 2.0% BBP-treated pregnant rats. The pair-fed and 2.0 % BBP-treated pregnant rats showed significant and comparable reductions in the adjusted weight gain. The number of live fetuses was lowered in the pair-fed group. However, the complete resorption of all the implanted embryos was not found in any of the pair-fed pregnant rats. The data suggest that the embryolethality observed in the 2.0 % BBP-treated pregnant rats is attributable to the effects o dietary BBP.

  20. Synthesis, antioxidant, enzyme inhibition and DNA binding studies of novel N-benzylated derivatives of sulfonamide

    Science.gov (United States)

    Abbas, Aadil; Murtaza, Shahzad; Tahir, Muhammad Nawaz; Shamim, Saima; Sirajuddin, Muhammad; Rana, Usman Ali; Naseem, Khadija; Rafique, Hummera

    2016-08-01

    A series of novel N-benzylated derivatives of sulfonamide were synthesized and characterized by FT-IR, NMR and XRD analysis. The synthesized compounds were assayed for their biological potential. The biological studies involved antioxidant, enzyme inhibition, and DNA interaction studies. Antioxidant potential was investigated by Ferric Reducing Antioxidant Power assay (FRAP) and DPPH free radical scavenging method, the capacity of synthesized compounds to inhibit the enzyme's activity was assayed by using the well-known Elman method whereas DNA interaction studies were carried out with the help UV-Vis absorption titration method. Moreover, a direct correlation between enzyme inhibition activity and concentration of the compounds was observed both in experimental and molecular docking studies. DNA interaction studies of the synthesized compounds showed weak interaction.

  1. Application of living radical polymerization to the synthesis of resist polymers for radiation lithography

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takashi [Nitto Denko Co. LTD., Shimohozumi 1-1-2, Ibaraki, Osaka 567-8680 (Japan); Ichikawa, Tsuneki [Division of Materials Chemistry, Graduate school of Engineering, Hokkaido University, Sapporo 060-8628 (Japan)]. E-mail: ichikawa@eng.hokudai.ac.jp

    2005-07-01

    Poly(styrene) and poly(methyl acrylate) with benzyl ester of carboxylic acid at the center of the polymer skeletons were synthesized by living radical polymerization for developing a new type of radiation resist with high resistivity to plasma etching and high sensitivity and spatial resolution to ionizing radiations. The initiators were benzyl esters with two functional groups for living radical polymerization on the benzyl and the carboxylic sides. Introduction of benzyl ester to the polymer skeletons changed the polymers from cross-link type to scission type upon {gamma}-irradiation. Irradiation of the polymers resulted in the binary change of the molecular weight, due to dissociative capture of secondary electrons by the benzyl ester, as M{sub n}R{sub 1}COOCH(C{sub 6}H{sub 5})R{sub 2}M{sub n}+e{sup -}->M{sub n}R{sub 1}COO{sup -}+{sup {center_dot}}CH(C{sub 6}H{sub 5})R{sub 2}M{sub n}. The generated polymer fragments were not decomposed by further irradiation, which suggests that the synthesized polymers have high resistivity to plasma etching.

  2. Radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Sønksen, Jens; Jakobsen, Henrik

    2014-01-01

    OBJECTIVE: The aim of this study was to compare oncological and functional outcomes between robot-assisted laparoscopic radical prostatectomy (RALP) and retropubic radical prostatectomy (RRP) during the initial phase with RALP at a large university hospital. MATERIAL AND METHODS: Patient and tumour...... surgery and at follow-up and they were asked to report their use of pads/diapers. Potency was defined as an IIEF-5 score of at least 17 with or without phosphodiesterase-5 inhibitors. Patients using up to one pad daily for security reasons only were considered continent. Positive surgical margins, blood...... loss and functional outcomes were compared between groups. RESULTS: Overall, 453 patients were treated with RRP and 585 with RALP. On multivariate logistic regression analyses, the type of surgery did not affect surgical margins (p = 0.96) or potency at 12 months (p = 0.7). Patients who had undergone...

  3. Benzyl-chloridobis(quinolin-8-olato)tin(IV).

    Science.gov (United States)

    Wang, Qibao

    2009-07-11

    In the title compound, [Sn(C(7)H(7))(C(9)H(6)NO)(2)Cl], the Sn(IV) ion is in a distorted octa-hedral coordination environment formed by the O and N atoms of two bis-chelating quinolin-8-olate ligands, a Cl atom and a C atom from a benzyl ligand. The axial sites are occupied by an N atom of a quinolinate ligand and the C atom of the benzyl ligand. The axial Sn-N bond is slightly shorter than the equatorial Sn-N bond.

  4. Benzyl­chloridobis(quinolin-8-olato)tin(IV)

    OpenAIRE

    Wang, Qibao

    2009-01-01

    In the title compound, [Sn(C7H7)(C9H6NO)2Cl], the SnIV ion is in a distorted octa­hedral coordination environment formed by the O and N atoms of two bis-chelating quinolin-8-olate ligands, a Cl atom and a C atom from a benzyl ligand. The axial sites are occupied by an N atom of a quinolinate ligand and the C atom of the benzyl ligand. The axial Sn—N bond is slightly shorter than the equatorial Sn—N bond.

  5. A convenient procedure for the synthesis of allyl and benzyl ethers from alcohols and phenols

    Indian Academy of Sciences (India)

    H Surya Prakash Rao; S P Senthilkumar

    2001-06-01

    Allyl and benzyl ethers of alcohols can be prepared conveniently and in high yield with allyl and benzyl bromide in the presence of solid potassium hydroxide without use of any solvent. Phenols can be converted to allyl ethers but are inert to benzylation under above conditions.

  6. Approach to a Facile and Selective Benzyl-Protection of Carbohydrates Based on Silyl Migration

    Institute of Scientific and Technical Information of China (English)

    WANG,Wei; LI,Xiao-Liu; ZHANG,Ping-Zhu; CHEN,Hua

    2008-01-01

    A convenient and selective benzyl protection of carbohydrates has been investigated on the basis of the silyl migration under the conventional benzylation conditions, developing a facile and short synthesis of methyl 2,3,6-tri-O-benzyl-a-D-glucopyranoside.

  7. Pulse radiolysis, flash photolysis, and shock wave study of the recombination H + benzyl yields toluene at 300 and 1,300-1,650 K

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, L.; Hippler, H.; Pagsberg, P.; Reihs, C.; Troe, J. (Institut fuer Physikalische Chemie der Universitaet Goettingen (West Germany) Riso National Laboratory (Denmark))

    1990-06-28

    Pulse radiolysis, discharge flash photolysis, and laser flash photolysis have been employed to study the recombination reaction H + benzyl {yields} toluene at room temperature. Both H atoms and benzyl radicals were monitored. The same reaction was studied directly in shock waves between 1,300 and 1.650 K. The value of the high-pressure recombination rate constant of (2.5 {plus minus} 0.8) {times} 10{sup 14} cm{sup 3} mol{sup {minus}1} s{sup {minus}1} was found to be independent of the temperature between 300 and 1,650 K. It is argued that high-pressure rate constants for other recombination reactions should also have very small temperature coefficients over wide temperature ranges. Room temperature rate constants for addition of H atoms to toluene, cycloheptatriene, p-xylene, benzene, phenyl, and p-methylbenzyl are also reported.

  8. Engineering Escherichia coli for renewable benzyl alcohol production

    Directory of Open Access Journals (Sweden)

    Shawn Pugh

    2015-12-01

    Full Text Available Benzyl alcohol is an aromatic hydrocarbon used as a solvent and an intermediate chemical in the pharmaceutical, cosmetics, and flavor/fragrance industries. The de novo biosynthesis of benzyl alcohol directly from renewable glucose was herein explored using a non-natural pathway engineered in Escherichia coli. Benzaldehyde was first produced from endogenous phenylpyruvate via three heterologous steps, including hydroxymandelate synthase (encoded by hmaS from Amycolatopsis orientalis, followed by (S-mandelate dehydrogenase (encoded by mdlB and phenylglyoxylate decarboxylase (encoded by mdlC from Pseudomonas putida ATCC 12633. The subsequent rapid and efficient reduction of benzaldehyde to benzyl alcohol occurred by the combined activity and native regulation of multiple endogenous alcohol dehydrogenases and/or aldo-keto reductases. Through systematic deletion of competing aromatic amino acid biosynthesis pathways to promote endogenous phenylpyruvate availability, final benzyl alcohol titers as high as 114±1 mg/L were realized, representing a yield of 7.6±0.1 mg/g on glucose and a ~5-fold improvement over initial strains.

  9. Iron-catalysed Negishi coupling of benzyl halides and phosphates.

    Science.gov (United States)

    Bedford, Robin B; Huwe, Michael; Wilkinson, Mark C

    2009-02-01

    Iron-based catalysts containing either 1,2-bis(diphenylphosphino)benzene or 1,3-bis(diphenylphosphino)propane give excellent activity and good selectivity in the Negishi coupling of aryl zinc reagents with a range of benzyl halides and phosphates.

  10. Biocatalytic oxidation of benzyl alcohol to benzaldehyde via hydrogen transfer

    NARCIS (Netherlands)

    Orbegozo, Thomas; Lavandera, Iván; Fabian, Walter M.F.; Mautner, Barbara; Vries, Johannes G. de; Kroutil, Wolfgang

    2009-01-01

    Various types of biocatalysts like oxidases, alcohol dehydrogenases, and microbial cells were tested for the oxidation of benzyl alcohol. Oxidases in combination with molecular oxygen led to low conversion. Alcohol dehydrogenases and microbial cells were tested in a hydrogen transfer reaction employ

  11. Intramolecular Homolytic Substitution with Amidyl Radicals: A Free-Radical Synthesis of Ebselen and Related Analogues.

    Science.gov (United States)

    Fong, Mei C.; Schiesser, Carl H.

    1997-05-16

    Irradiation of a water-cooled benzene solution of pyridine-2-thioneoxycarbonyl (PTOC) imidate esters 9 derived from N-butyl-2-(benzylseleno)benzamide (6, R = Bu), 2-(benzylseleno)-N-hexylbenzamide (6, R = Hex), N-benzyl-2-(benzylseleno)benzamide (6, R = Bn), and 2-(benzylseleno)-N-cyclohexylbenzamide (6, R = c-Hex) with a 250-W low-pressure mercury lamp affords the corresponding 1,2-benzisoselenazol-3(2H)-ones (1) in yields of 81-91% (R = primary alkyl) and 45% (R = c-Hex). Presumably, these transformations involve formation of amidyl radicals 2 which undergo subsequent intramolecular homolytic substitution at the selenium atom with expulsion of a benzyl radical. PTOC imidate esters derived from 2-(benzylseleno)benzanilide (6, R = Ph) and 2-(benzylseleno)-N-tert-butylbenzamide (6, R = t-Bu) were unable to be prepared in this manner. 1,2-Benzisoselenazol-3(2H)-ones (1, R = Ph, Hex, i-Pr, t-Bu) could also be prepared in 76-85% yield by reaction of the corresponding 2,2'-diselenobis(benzamide) (15) with benzoyl or tert-butyl peroxide. The mechanisms of these transformations are discussed.

  12. Visible absorptions of potential diffuse ISM hydrocarbons: C$_9$H$_9$ and C$_9$H$_5$ radicals

    CERN Document Server

    Steglich, Mathias; Maier, John P

    2016-01-01

    The laboratory detection of previously unobserved resonance-stabilized C$_9$H$_5$ and C$_9$H$_9$ radicals in the supersonic expansion of a hydrocarbon discharge source is reported. The radicals are tentatively assigned as acetylenic-substituted cyclopentadienyl C$_9$H$_5$ and vinyl-substituted benzyl C$_9$H$_9$ species. They are found to feature visible absorption bands that coincide with a few very weak diffuse interstellar bands toward HD183143 and HD204827.

  13. Synthesis of benzyl chlorides and cycloveratrylene macrocycles using benzylic alcohols under homogeneous catalysis by HCl/dioxane

    Directory of Open Access Journals (Sweden)

    Yolanda Marina Vargas-Rodríguez

    2012-01-01

    Full Text Available The synthesis of benzyl chlorides, cyclic derivatives cyclotriveratrylene and cyclotripiperotrylene were carried out in using the HCl/dioxane system as a catalyst. The reaction proceeded with high selectivity and is sensitive to the number of alkyl and methoxy substituent on the aromatic ring.

  14. Ignorance Radicalized

    Directory of Open Access Journals (Sweden)

    Gergo Somodi

    2009-12-01

    Full Text Available The aim of this paper is twofold. I criticize Michael Devitt's linguistic---as opposed to Chomsky's psychological---conception of linguistics on the one hand, and I modify his related view on linguistic intuitions on the other. I argue that Devitt's argument for the linguistic conception is in conflict with one of the main theses of that very conception, according to which linguistics should be about physical sentence tokens of a given language rather than about the psychologically real competence of native speakers. The basis of this conflict is that Devitt's view on language, as I will show, inherits too much from the criticized Chomskian view. This is also the basis of Devitt's strange claim that it is the linguist, and not the ordinary speaker, whose linguistic intuition should have an evidential role in linguistics. I will argue for the opposite by sketching a view on language that is more appropriate to the linguistic conception. That is, in criticizing Devitt, I am not defending the Chomskian approach. My aim is to radicalize Devitt's claims.

  15. 3-Benzyl-5-methyl-1,2-benzoxazole 2-oxide

    Directory of Open Access Journals (Sweden)

    G. Anuradha

    2012-10-01

    Full Text Available In the title compound, C15H13NO2, the isoxazole unit and the attached benzene ring are almost coplanar, making a dihedral angle of 1.42 (8°. The benzyl ring is inclined to the isoxazole ring by 74.19 (8° and is in a +sc conformation with respect to the benzisoxazole unit. In the crystal, C—H...O hydrogen bonds link the molecules, forming zigzag chains propagating along the b axis. There are also π–π interactions present involving the isoxazole and benzyl rings [centroid–centroid distance = 3.5209 (10 Å], and C—H...π interactions involving the benzene ring of the benzoisoxazole unit and the methylene bridging group.

  16. Rh2(esp)2-catalyzed allylic and benzylic oxidations.

    Science.gov (United States)

    Wang, Yi; Kuang, Yi; Wang, Yuanhua

    2015-04-07

    The dirhodium(II) catalyst Rh2(esp)2 allows direct solvent-free allylic and benzylic oxidations by T-HYDRO with a remarkably low catalyst loading. This method is operationally simple and scalable at ambient temperature without the use of any additives. The high catalyst stability in these reactions may be attributed to a dirhodium(II,II) catalyst resting state, which is less prone to decomposition.

  17. Hyaluronan Benzyl Ester as a Scaffold for Tissue Engineering

    OpenAIRE

    2009-01-01

    Tissue engineering is a multidisciplinary field focused on in vitro reconstruction of mammalian tissues. In order to allow a similar three-dimensional organization of in vitro cultured cells, biocompatible scaffolds are needed. This need has provided immense momentum for research on “smart scaffolds” for use in cell culture. One of the most promising materials for tissue engineering and regenerative medicine is a hyaluronan derivative: a benzyl ester of hyaluronan (HYAFF®). HYAFF® can be proc...

  18. Tertiary amines nucleophilicity in quaternization reaction with benzyl chloride

    Directory of Open Access Journals (Sweden)

    Ksenia S. Yutilova

    2016-03-01

    Full Text Available Quaternization reaction of tertiary amines with benzyl chloride was investigated. Reaction orders with respect to the reactants were determined. Kinetic scheme of quaternization reaction was found to be corresponding to reversible process. An influence of amines basicity and steric factor of alkyl substituent bound to the nitrogen atom on tertiary amines reactivity as nucleophiles was studied. It was shown that the rate constants of direct reaction step may serve as a measure of nucleophilicity of amines.

  19. Synthesis and Properties of Polyurethane Resins from Liquefied Benzylated Wood

    Institute of Scientific and Technical Information of China (English)

    Yu Ping WEI; Fa CHENG; Hou Ping LI; Jiu Gao YU

    2005-01-01

    In this paper, polyurethane resins were synthesized from liquefied benzylated wood and TDI (toluene diisocyanate)-TMP (trihydromethylene propane) prepolymer. And the relation between microphase structure and properties of PU samples were also studied. The results indicated that coatings obtained had good mechanical and thermal properties. The amount of the curing agent has great effect on the degree of phase segregation. In addition, with increased the curing agent amount, the thermal stabilities were also improved.

  20. Multichromic polymers of benzotriazole derivatives: Effect of benzyl substitution

    Energy Technology Data Exchange (ETDEWEB)

    Yigitsoy, Basak [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Abdul Karim, S.M. [Department of Arts and Sciences, Ahsanullah University of Science and Technology, Dhaka 1208 (Bangladesh); Balan, Abidin; Baran, Derya [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Toppare, Levent, E-mail: toppare@metu.edu.t [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Department of Biotechnology, Middle East Technical University, 06531 Ankara (Turkey); Department of Polymer Science and Technology, Middle East Technical University, 06531 Ankara (Turkey)

    2011-02-01

    Two electroactive monomers 1-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3]triazole (BBTA) and 2-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3]triazole (BBTS) were synthesized with satisfactory yields. The effect of substitution site on electrochemical and optical properties was investigated with cyclic voltammetry and spectroelectrochemical studies. Results showed that position of pendant group alters the electronic structure of the resulting polymer causing different optical and electrochemical behaviors. Symmetrically positioned benzyl unit on benzotriazole moiety resulted in a neutral state red polymer, PBBTS, having multi-colored property in its different oxidized and reduced states. Its analogue PBBTA exhibited maximum absorption at 390 nm in its neutral state and also revealed multicolored electrochromic property upon stepwise oxidation. Very different optical band gap values were calculated: 1.55 eV and 2.25 eV for PBBTS and PBBTA, respectively.

  1. Friction behavior of 304 stainless steel of varying hardness lubricated with benzene and some benzyl structures

    Science.gov (United States)

    Buckley, D. H.

    1974-01-01

    The lubricating properties of some benzyl and benzene structures were determined by using 304 stainless steel surfaces strained to various hardness. Friction coefficients and wear track widths were measured with a Bowden-Leben type friction apparatus by using a pin-on-disk specimen configuration. Results obtained indicate that benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol resulted in the lowest friction coefficients for 304 stainless steel, while benzyl ether provided the least surface protection and gave the highest friction. Strainhardening of the 304 stainless steel prior to sliding resulted in reduced friction in dry sliding. With benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol changes in 304 stainless steel hardness had no effect upon friction behavior.

  2. Synthesis of Pharmaceutical Intermediates by Toluene Benzylation over Heteropoly Acids on Different Support

    Institute of Scientific and Technical Information of China (English)

    V. V. Bokade; G.D. Yadav

    2007-01-01

    Selective formation of pharmaceutical intermediates like diphenylmethane, dimethyldiphenylmethane, benzyl toluene and benzoic acid by liquid phase, toluene benzylation with benzyl chloride as a benzylating agent, was systematically studied over plane clay (K-10, montmorillonite),plane H-Beta, plane MFI structured titanosilicate (TS-1) and heteropoly acids [HPA, namely dodecasupported on clay, H-beta and TS-1. The 20%TPA/Clay, 30%TPA/H-Beta and 30%TPA/TS-1, were observed to be the best catalyst samples over plane clay, plane H-Beta and plane TS-1. The catalyst samples are compared with respect to benzyl chloride conversion and selectivities for diphenylmethane,dimethyl-diphenylmethane, benzyl toluene and benzoic acid. The reaction follows the pseudo-first order rate power law model. The apparent rate constants are calculated and compared with the reported ones.

  3. Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates

    OpenAIRE

    Qinggang Mei; Chun Wang; Weicheng Yuan; Guolin Zhang

    2015-01-01

    A strategy for selective mono-, di- and tri-O-methylation of kaempferol, predominantly on the basis of selective benzylation and controllable deacetylation of kaempferol acetates, was developed. From the selective deacetylation and benzylation of kaempferol tetraacetate (1), 3,4′,5,-tri-O-acetylkaempferol (2) and 7-O-benzyl-3,4′5,-tri-O-acetylkaempferol (8) were obtained, respectively. By controllable deacetylation and followed selective or direct methylation of these two intermediates, eight...

  4. Aerobic dehydrogenative α-diarylation of benzyl ketones with aromatics through carbon-carbon bond cleavage.

    Science.gov (United States)

    More, Nagnath Yadav; Jeganmohan, Masilamani

    2014-02-01

    Substituted benzyl ketones reacted with aromatics in the presence of K2S2O8 in CF3COOH at room temperature, yielding α-diaryl benzyl ketones through a carbon-carbon bond cleavage. In the reaction, two new carbon-carbon bonds were formed and one carbon-carbon bond was cleaved. It is very interesting that two different nucleophiles such as benzyl ketones and aromatics were coupled together without metal, which is unusual in organic synthesis.

  5. Photocatalytic benzylic C–H bond oxidation with a flavin scandium complex

    OpenAIRE

    Mühldorf, Bernd; Wolf, Robert

    2015-01-01

    The enhanced reduction potential of riboflavin tetraacetate coordinating to scandium triflate enables the challenging photocatalytic C–H oxidation of electron-deficient alkylbenzenes and benzyl alcohols.

  6. New preparation of benzylic aluminum and zinc organometallics by direct insertion of aluminum powder.

    Science.gov (United States)

    Blümke, Tobias D; Groll, Klaus; Karaghiosoff, Konstantin; Knochel, Paul

    2011-12-16

    The reaction of commercial Al-powder (3 equiv) and InCl(3) (1-5 mol %) with benzylic chlorides provides various functionalized benzylic aluminum sesquichlorides under mild conditions (THF, 20 °C, 3-24 h) without homocoupling (organometallics reacted smoothly with various electrophiles (Pd-catalyzed cross-couplings, or Cu-mediated acylations, allylations, or 1,4-addition reactions). Electron-poor benzylic chlorides or substrates prone to Wurtz coupling can be converted to benzylic zinc compounds by the reaction of Al-powder in the presence of ZnCl(2).

  7. [N-Benzyl-N-(diphenylphosphanylmethylpyridin-2-amine]chloridomethylplatinum(II

    Directory of Open Access Journals (Sweden)

    Chong-Qing Wan

    2011-01-01

    Full Text Available In the mononuclear title complex, [Pt(CH3Cl(C25H23N2P], the N-benzyl-N-(diphenylphosphanylmethylpyridin-2-amine functions as a bidentate ligand with the pyridyl N atom and the phosphine P atom chelating the PtII ion, forming a six-membered metallocycle. The PtII atom adopts a square-planar coordination geometry with one methyl group and one chloride ligand bonding to the metal center in a cis relationship. C—H...π and C—H...Cl interactions help to consolidate the packing.

  8. Multireference Calculation of the Photodissociation of Benzyl Chloride

    Institute of Scientific and Technical Information of China (English)

    CAO Jun; LIU Ya-Jun; FANG Wei-Hai

    2007-01-01

    The photodissociation mechanism of benzyl chloride (BzCl) under 248 nm has been investigated by the complete active space SCF (CASSCF) method by calculating the geometries of the ground (S0) and lower excited states,the vertical (Tv) and adiabatic (T0) excitation energies of the lower states,and the dissociation reaction pathways on the potential energy surfaces (PES) of S1, T1 and T2 states.The calculated results clearly elucidated the photodissociation mechanism of BzCl,and indicated that the photodissociation on the PES of T1 state is the most favorable.

  9. A radical approach to radical innovation

    OpenAIRE

    Deichmann, Dirk; van der Ende, Jan

    2014-01-01

    textabstractInnovation pays. Amazon, Apple, Facebook, Google – nearly every one of today’s most successful companies has a talent for developing radical new ideas. But how best to encourage radical initiative taking from employees, and does their previous success or failure at it play a role?

  10. Oxidative cleavage of benzylic C-N bonds under metal-free conditions.

    Science.gov (United States)

    Gong, Jin-Long; Qi, Xinxin; Wei, Duo; Feng, Jian-Bo; Wu, Xiao-Feng

    2014-10-14

    An interesting procedure for the oxidative cleavage of benzylic C-N bonds has been developed. Using TBAI as the catalyst and H2O2 as the oxidant, various benzylamines were transformed into their corresponding aromatic aldehydes in moderate to good yields. Notably, this is the first example of an oxidative cleavage of benzylic C-N bonds under metal-free conditions.

  11. Infrared spectroscopy of organic free radicals related to combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Weisshaar, J.C. [Univ. of Wisconsin, Madison (United States)

    1993-12-01

    The primary long-term goal of this work is to develop new techniques for measuring vibrational spectra of polyatomic neutral free radicals. The authors explore a variation of resonant two-photon ionization (R2PI) in which tunable {omega}{sub IR} excites the radical vibrationally and {omega}{sub UV} selectively ionizes only the vibrationally excited molecules. Development of the IR + UV R2PI experiment is underway. In the meantime, the authors have used optical R2PI and pulsed field ionization (PFI) detection to obtain new vibrational spectra of species such as the benzyl and phenylsilane cations. In benzyl, a great deal was learned about the vibronic coupling mechanism in the mixed q{sup 2}A{sub 2}-2{sup 2}B{sub 2} system near 450 nm by projecting the mixed states onto the manifold of cation vibrational states. In phenylsilane{sup +}, we find that the sixfold barrier to internal rotation of the silyl group is small (V{sub 6} = +19 cm{sup {minus}1}). We are beginning to understand the mechanisms of coupling of torsional states with vibration, overall rotation, and other electronic states. In addition, we are developing a new model of internal rotation in aromatic compounds based on Prof. Frank Weinhold`s natural resonance theory.

  12. FTIR study of hydrogen bonding between substituted benzyl alcohols and acrylic esters

    Directory of Open Access Journals (Sweden)

    P. Sivagurunathan

    2016-11-01

    Full Text Available Hydrogen bonding between substituted benzyl alcohols (benzyl alcohol, o-aminobenzyl alcohol, o-chlorobenzyl alcohol and o-nitrobenzyl alcohol and acrylic esters (methyl methacrylate, ethyl methacrylate is studied in carbon tetrachloride by using the FTIR spectroscopic method. Utilizing the Nash method, the formation constant (K of the 1:1 complexes is calculated. Using the K value, the Gibbs free energy change (ΔG0 is also calculated. The calculated formation constant and Gibbs free energy change values vary with the substituent of benzyl alcohol and ester chain length, which suggests that the proton donating ability of substituted benzyl alcohols is in the order: o-aminobenzyl alcohol < benzyl alcohol < o-chlorobenzyl alcohol < o-nitrobenzyl alcohol, and proton accepting ability of acrylic esters is in the order: methyl methacrylate < ethyl methacrylate.

  13. Synthesis and Anti-HIV-1 Activity of New MKC-442 Analogues with an Alkynyl-Substituted 6-Benzyl Group

    DEFF Research Database (Denmark)

    Aly, Youssef L.; Pedersen, Erik Bjerreg.; La Colla, Paolo;

    2007-01-01

    Synthesis and antiviral activities are reported of a series of 6-(3-alkynyl benzyl)-substituted analogues of MKC-442 (6-benzyl-1-(ethoxymethyl)-5-isopropyluracil), a highly potent agent against HIV. The 3-alkynyl group is assumed to give a better stacking of the substituted benzyl group to revers...

  14. Antimicrobial, antioxidant, cytotoxic and molecular docking properties of N-benzyl-2,2,2-trifluoroacetamide

    Science.gov (United States)

    Balachandran, C.; Kumar, P. Saravana; Arun, Y.; Duraipandiyan, V.; Sundaram, R. Lakshmi; Vijayakumar, A.; Balakrishna, K.; Ignacimuthu, S.; Al-Dhabi, N. A.; Perumal, P. T.

    2015-02-01

    N-Benzyl-2,2,2-trifluoroacetamide was obtained by acylation of benzylamine with trifluoroacetic anhydride using Friedel-Crafts acylation method. The synthesised compound was confirmed by spectroscopic and crystallographic techniques. N-Benzyl-2,2,2 -trifluoroacetamide was assessed for its antimicrobial, antioxidant, cytotoxic and molecular docking properties. It showed good antifungal activity against tested fungi and moderate antibacterial activity. The minimum inhibitory concentration values of N-benzyl-2,2,2 -trifluoroacetamide against fungi were 15.62 μg/mL against A. flavus, 31.25 μg/mL against B. Cinerea and 62.5 μg/mL against T. mentagrophytes, Scopulariopsis sp., C. albicans and M. pachydermatis. N-Benzyl-2,2,2-trifluoroacetamide showed 78.97 ± 2.24 of antioxidant activity at 1,000 μg/mL. Cupric ion reducing antioxidant capacity of N-benzyl-2,2,2-trifluoroacetamide was dependent on the concentration. Ferric reducing antioxidant power assay of N-benzyl-2,2,2-trifluoroacetamide showed (1.352 ± 0.04 mM Fe(II)/g) twofold higher value compared to the standard. N-Benzyl-2,2,2-trifluoroacetamide showed 75.3 % cytotoxic activity at the dose of 200 μg/mL with IC50 (54.7 %) value of 100 μg/mL. N-Benzyl-2,2,2-trifluoroacetamide was subjected to molecular docking studies for the inhibition AmpC beta-lactamase, Glucosamine-6-Phosphate Synthase and lanosterol 14 alpha-demethylase (CYP51) enzymes which are targets for antibacterial and antifungal drugs. Docking studies of N-benzyl-2,2,2-trifluoroacetamide showed low docking energy. N-Benzyl-2,2,2-trifluoroacetamide can be evaluated further for drug development.

  15. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  16. [Lavoisier and radicals].

    Science.gov (United States)

    Lafont, Olivier

    2007-01-01

    Lavoisier and his co-workers (Guyton de Morveau, Bertholet, Fourcroy) considered that acids were constituted of oxygen and of something else that they called radicals. These radicals were known in some cases, i.e. nitrogen for nitrous acid, carbon for carbonic acid, phosphorus for phosphoric acid. In the case of sulfur, the sulfuric radical could be associated with different quantities of oxigen leading to sulfuric or sulfurous acids. In other cases radicals remained unknown at the time i.e. muriatic radical for muriatic acid, or benzoyl radical for benzoic acid. It is interesting to notice that Lavoisier evoked the case of compound radicals constituted of different substances such as carbon and hydrogen.

  17. UV spectra and kinetics of radicals produced in the gas phase reactions of Cl, F and OH with toluene

    DEFF Research Database (Denmark)

    Markert, F.; Pagsberg, P.

    1993-01-01

    atoms the benzyl radical was the only reaction product observed. The addition reactions Y + C6H5-CH3 --> Y-C6H5-CH3 were observed with Y = F and OH, and the ultraviolet absorption spectra of the short-lived adducts have been recorded. Rate constants for the abstraction and addition reactions were......The gas phase reactions of Cl, F and OH with toluene have been studied by pulse radiolysis combined with time-resolved UV spectroscopy. The formation of benzyl radicals via the abstraction reactions C6H5-CH3 + X --> C6H5-CH2 + HX was observed with X = Cl, F and OH. In the reaction with chlorine...

  18. BENZYLATION AND CHARACTERIZATION OF COLD NAOH/UREA PRE-SWELLED BAMBOO

    Directory of Open Access Journals (Sweden)

    Ming-Fei Li,

    2012-02-01

    Full Text Available Ball-milled bamboo was pre-swelled with a cold aqueous solution of NaOH and urea, and then reacted directly with benzyl chloride to synthesize benzylated bamboo. The effects of the molar ratio of benzyl chloride to OH groups in the bamboo (1 to 4, the reaction temperature (70 to 110 °C, and the reaction time (2 to 8 h on both the product yield and the degree of substitution (DS were evaluated. Yields between 67.6 and 94.0% and DS between 0.31 and 0.74 of the benzylated bamboo were obtained under such conditions. The incorporation of benzyl groups was evidenced by FT-IR and CP/MAS 13C-NMR spectroscopy. It was found that the crystalline structure of the native ball-milled bamboo was markedly damaged after modification. In addition, the benzylated bamboo was subjected to thermal degradation at a high temperature with an increase in substitution. It was suggested that the benzylated bamboo with a low crystallinity as well as large non-polar groups is promising as a filler for use in the composite material industry.

  19. Solvent effects in the reaction between piperazine and benzyl bromide

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2007-11-01

    The reaction between piperazine and benzyl bromide was studied conductometrically and the second order rate constants were computed. These rate constants determined in 12 different protic and aprotic solvents indicate that the rate of the reaction is influenced by electrophilicity (), hydrogen bond donor ability () and dipolarity/polarizability (*) of the solvent. The LSER derived from the statistical analysis indicates that the transition state is more solvated than the reactants due to hydrogen bond donation and polarizability of the solvent while the reactant is more solvated than the transition state due to electrophilicity of the solvent. Study of the reaction in methanol, dimethyl formamide mixtures suggests that the rate is maximum when dipolar interactions between the two solvents are maximum.

  20. 1-Benzyl-5-bromoindoline-2,3-dione

    Directory of Open Access Journals (Sweden)

    Yassine Kharbach

    2016-04-01

    Full Text Available In the title compound, C15H10BrNO2, the indoline ring system, the two ketone O atoms and the Br atom lie in a common plane, with the largest deviation from the mean plane being 0.073 (1 Å for the Br atom. The fused-ring system is nearly perpendicular to the benzyl ring, as indicated by the dihedral angle between them of 74.58 (10°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds and by π–π interactions [inter-centroid distance = 3.625 (2 Å], forming a two-dimensional structure.

  1. 1-Benzyl-3-[(trimethylsilylmethyl]benzimidazolium chloride monohydrate

    Directory of Open Access Journals (Sweden)

    Mehmet Akkurt

    2010-07-01

    Full Text Available The title compound, C18H23N2Si+·Cl−·H2O, was synthesized from 1-[(trimethylsilylmethyl]benzimidazole and benzyl chloride in dimethylformamide. The benzimidazole ring system is approximately planar, with a maximum deviation of 0.022 (2 Å, and makes an angle of 74.80 (12° with the phenyl ring. The crystal packing is stabilized by O—H...Cl, C—H...Cl, C—H...O and C—H...π interactions between symmetry-related molecules together with π–π stacking interactions between the imidazolium and benzene rings [centroid–centroid distance = 3.5690 (15 Å] and between the benzene rings [centroid–centroid distance = 3.7223 (14 Å].

  2. Contemporary Radical Prostatectomy

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2011-01-01

    Full Text Available Purpose. Patients diagnosed with clinically localized prostate cancer have more surgical treatment options than in the past. This paper focuses on the procedures' oncological or functional outcomes and perioperative morbidities of radical retropubic prostatectomy, radical perineal prostatectomy, and robotic-assisted laparoscopic radical prostatectomy. Materials and Methods. A MEDLINE/PubMed search of the literature on radical prostatectomy and other new management options was performed. Results. Compared to the open procedures, robotic-assisted radical prostatectomy has no confirmed significant difference in most literatures besides less blood loss and blood transfusion. Nerve sparing is a safe means of preserving potency on well-selected patients undergoing radical prostatectomy. Positive surgical margin rates of radical prostatectomy affect the recurrence and survival of prostate cancer. The urinary and sexual function outcomes have been vastly improved. Neoadjuvant treatment only affects the rate of positive surgical margin. Adjuvant therapy can delay and reduce the risk of recurrence and improve the survival of the high risk prostate cancer. Conclusions. For the majority of patients with organ-confined prostate cancer, radical prostatectomy remains a most effective approach. Radical perineal prostatectomy remains a viable approach for patients with morbid obesity, prior pelvic surgery, or prior pelvic radiation. Robot-assisted laparoscopic prostatectomy (RALP has become popular among surgeons but has not yet become the firmly established standard of care. Long-term data have confirmed the efficacy of radical retropubic prostatectomy with disease control rates and cancer-specific survival rates.

  3. Forgotten Radicals in Biology

    OpenAIRE

    2008-01-01

    Redox reactions play key roles in intra- and inter-cellular signaling, and in adaptative processes of tissues towards stress. Among the major free radicals with essential functions in cells are reactive oxygen species (ROS) including superoxide anion (O2 •-), hydroxyl radical (•OH) and reactive nitrogen species (RNS) such as nitric oxide (•NO). In this article, we review the forgotten and new radicals with potential relevance to cardiovascular pathophysiology. Approximately 0.3% of O2 •- pres...

  4. Photocatalytic oxidation of primary and secondary benzyl alcohol catalyzed by two coenzyme NAD+ models

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Photocatalytic oxidation of primary and secondary benzyl alcohol to corresponding benzaldehyde or acetophenone using Acr+ClO4- or PhAcr+ClO4- as photocatalysts under visible light irradiation at room temperature.

  5. Polystyrene-supported Benzyl Selenide: An Efficient Reagent for Highly Stereocontrolled Synthesis of Substituted Olefins

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Polystyrene-supported benzyl selenide has been prepared. This novel reagent was treated with LDA to produce a selenium stabilized carbanion, which reacted with alkyl halide, followed by selenoxide syn-elimination, to give substituted olefins stereospecificly.

  6. A Direct Transformation of Aryl Aldehydes to Benzyl Iodides Via Reductive Iodination

    Energy Technology Data Exchange (ETDEWEB)

    Ruso, Jayaraman Sembian; Rajendiran, Nagappan; Kumaran, Rajendran Senthil [Univ. of Madras, Chennai (India)

    2014-02-15

    A facile transformation of aryl aldehydes to benzyl iodides through one-pot reductive iodination is reported. This protocol displays remarkable functional group tolerance and the title compound was obtained in good to excellent yield.

  7. Photostimulated SRN 1 Reactions of Benzyl Chloride with Carbazolyl Nitrogen Anion

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The photostimulated reactions of benzyl chloride with carbazolyl nitrogen anion in dimethyl sulfoxide gave 9-benzylcarbazole and 3-benzylcarbazole.The reactions are suggested in term of SRN1 mechanism of nucleophilic substitution.

  8. Palladium-catalyzed Cascade Cyclization-Coupling Reaction of Benzyl Halides with N,N-Diallylbenzoylamide

    Institute of Scientific and Technical Information of China (English)

    Yi Min HU; Yu ZHANG; Jian Lin HAN; Cheng Jian ZHU; Yi PAN

    2003-01-01

    A novel type of palladium-catalyzed cascade cyclization-coupling reaction has been found. Reaction of N, N-diallylbenzoylamide 1 with benzyl halides 2 afforded the corresponding dihydropyrroles 3 in moderate to excellent yields.

  9. Selective oxidation of benzylic alcohols using copper-manganese mixed oxide nanoparticles as catalyst

    Directory of Open Access Journals (Sweden)

    Roushown Ali

    2015-07-01

    Full Text Available The catalytic activity of copper-manganese (CuMn2 mixed oxide nanoparticles (Cu/Mn = 1:2 has been studied for the selective oxidation of benzylic alcohols to the corresponding aldehydes using molecular oxygen as an oxidizing agent. The CuMn2 mixed oxide showed excellent catalytic activity for the oxidation of benzylic alcohols to the corresponding aldehydes with high selectivity (>99%. The complete conversion (100% of all the benzylic alcohols to the corresponding aldehydes is achieved within a short reaction period at 102 °C. The catalytic performance is obtained to be dependent on the electronic and steric effects of the substituents present on the phenyl ring. Electron withdrawing and bulky groups attached to the phenyl ring required longer reaction time for a complete conversion of the benzylic alcohols.

  10. Wheat bran valorisation: Towards photocatalytic nanomaterials for benzyl alcohol photo-oxidation.

    Science.gov (United States)

    Ouyang, Weiyi; Reina, Jose M; Kuna, Ewelina; Yepez, Alfonso; Balu, Alina M; Romero, Antonio A; Colmenares, Juan Carlos; Luque, Rafael

    2016-07-13

    In this work, we have successfully synthesized a set of titania photocatalytic nanocomposites by the incorporation of different TiO2 content on wheat bran residues. The obtained catalysts were characterized by different techniques including UV-Vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Transmission Electron Microscopy (TEM) while their photocatalytic activity was investigated in the oxidation of benzyl alcohol under UV light irradiation. Benzaldehyde yields were ca. 20%, with conversion in the systems of ca. 33% of benzyl alcohol by using 10%Ti-Bran catalyst, as compared to 33% yield to the target product (quantitative conversion of benzyl alcohol) using commercial pure TiO2 (P-25). The photocatalytic activity results indicate that designed waste-derived nanomaterials with low TiO2 content can efficiently photocatalyze the conversion of benzyl alcohol with relative high selectivity towards benzaldehyde.

  11. SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES CONTAINING CROWN ETHER AND BENZYL ETHER MOIETIES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.

  12. Study of selected benzyl azides by UV photoelectron spectroscopy and mass spectrometry

    Science.gov (United States)

    Pinto, R. M.; Olariu, R. I.; Lameiras, J.; Martins, F. T.; Dias, A. A.; Langley, G. J.; Rodrigues, P.; Maycock, C. D.; Santos, J. P.; Duarte, M. F.; Fernandez, M. T.; Costa, M. L.

    2010-09-01

    Benzyl azide and the three methylbenzyl azides were synthesized and characterized by mass spectrometry (MS) and ultraviolet photoelectron spectroscopy (UVPES). The electron ionization fragmentation mechanisms for benzyl azide and their methyl derivatives were studied by accurate mass measurements and linked scans at constant B/ E. For benzyl azide, in order to clarify the fragmentation mechanism, labelling experiments were performed. From the mass analysis of methylbenzyl azides isomers it was possible to differentiate the isomers ortho, meta and para. The abundance and nature of the ions resulting from the molecular ion fragmentation, for the three distinct isomers of substituted benzyl azides, were rationalized in terms of the electronic properties of the substituent. Concerning the para-isomer, IRC calculations were performed at UHF/6-31G(d) level. The photoionization study of benzyl azide, with He(I) radiation, revealed five bands in the 8-21 eV ionization energies region. From every photoelectron spectrum of methylbenzyl azides isomers it has been identified seven bands, on the same range as the benzyl azide. Interpretation of the photoelectron spectra was accomplished applying Koopmans' theorem to the SCF orbital energies obtained at HF/6-311++G(d, p) level.

  13. Orgasm after radical prostatectomy

    NARCIS (Netherlands)

    Koeman, M; VanDriel, MF; Schultz, WCMW; Mensink, HJA

    1996-01-01

    Objective To evaluate the ability to obtain and the quality of orgasm after radical prostatectomy, Patients and methods The orgasms experienced after undergoing radical prostatectomy were evaluated in 20 men (median age 65 years, range 56-76) using a semi-structured interview and a self-administered

  14. The Radicalization Puzzle [video

    OpenAIRE

    Mohammed Hafez; Center for Homeland Defense and Security Naval Postgraduate School

    2015-01-01

    This 20 minute lecture, by Dr. Mohammad Hafez of the Naval Postgraduate School examines the driving factors behind the process of radicalization, turning seemingly ordinary men and women into potential terrorists. The lecture is based on the article "The Radicalization Puzzle: A Theoretical Synthesis of Empirical Approaches to Homegrown Extremism" in Studies in Conflict and Terrorism, by Mohammad Hafez and Creighton Mullins.

  15. Dietary Exposure to Benzyl Butyl Phthalate in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; JIANG Ding Guo; SUI Hai Xia; WU Ping Gu; LIU Ai Dong; YANG Da Jin; LIU Zhao Ping; SONG Yan; LI Ning

    2016-01-01

    ObjectiveBenzyl butyl phthalate (BBP) is a plasticizer used in food contact materials. Dietary exposure to BBP might lead to reproduction and developmental damages to human. The present paper was aimed to assess the health risk of BBP dietary exposure in Chinese population. MethodsThe BBP contents were detected in 7409 food samples from 25 foodcategories by gas chromatography-mass spectrometry operated in selected ion monitoring (SIM) mode. The dietary exposures of BBP in different age and sex groups were estimated by combining the content data with food consumption data derived from 2002 China National Nutrient and Health Survey, and evaluated according to the tolerable daily intake (TDI) of BBP established by European Food safety Agency. ResultsIt was found that BBP was undetectable in most samples and the highest level was 1.69 mg/kg detected in a vegetable oil sample. The average dietary exposure of BBP in people aged≥2 years was 1.03 μg/kgbw perday and the highest average exposure was found in 2-6 years old children (1.98 μg/kg bw perday). The BBP exposure in 7-12 months old children excessed 10% of tolerable daily intake (TDI) in worst scenario. ConclusionThe health risk of BBP dietary exposure in Chinese population is low and, considering BBP alone, there is no safety concern.

  16. Pentanol and Benzyl Alcohol Attack Bacterial Surface Structures Differently

    Science.gov (United States)

    Yano, Takehisa; Miyahara, Yoshiko; Morii, Noriyuki; Okano, Tetsuya

    2015-01-01

    The genus Methylobacterium tolerates hygiene agents like benzalkonium chloride (BAC), and infection with this organism is an important public health issue. Here, we found that the combination of BAC with particular alcohols at nonlethal concentrations in terms of their solitary uses significantly reduced bacterial viability after only 5 min of exposure. Among the alcohols, Raman spectroscopic analyses showed that pentanol (pentyl alcohol [PeA]) and benzyl alcohol (BzA) accelerated the cellular accumulation of BAC. Fluorescence spectroscopic assays and morphological assays with giant vesicles indicated that PeA rarely attacked membrane structures, while BzA increased the membrane fluidity and destabilized the structures. Other fluorescent spectroscopic assays indicated that PeA and BzA inactivate bacterial membrane proteins, including an efflux pump for BAC transportation. These findings suggested that the inactivation of membrane proteins by PeA and BzA led to the cellular accumulation but that only BzA also enhanced BAC penetration by membrane fluidization at nonlethal concentrations. PMID:26519389

  17. Salvage robotic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Samuel D Kaffenberger

    2014-01-01

    Full Text Available Failure of non-surgical primary treatment for localized prostate cancer is a common occurrence, with rates of disease recurrence ranging from 20% to 60%. In a large proportion of patients, disease recurrence is clinically localized and therefore potentially curable. Unfortunately, due to the complex and potentially morbid nature of salvage treatment, radical salvage surgery is uncommonly performed. In an attempt to decrease the morbidity of salvage therapy without sacrificing oncologic efficacy, a number of experienced centers have utilized robotic assistance to perform minimally invasive salvage radical prostatectomy. Herein, we critically evaluate the existing literature on salvage robotic radical prostatectomy with a focus on patient selection, perioperative complications and functional and early oncologic outcomes. These results are compared with contemporary and historical open salvage radical prostatectomy series and supplemented with insights we have gained from our experience with salvage robotic radical prostatectomy. The body of evidence by which conclusions regarding the efficacy and safety of robotic salvage radical prostatectomy can be drawn comprises fewer than 200 patients with limited follow-up. Preliminary results are promising and some outcomes have been favorable when compared with contemporary open salvage prostatectomy series. Advantages of the robotic platform in the performance of salvage radical prostatectomy include decreased blood loss, short length of stay and improved visualization. Greater experience is required to confirm the long-term oncologic efficacy and functional outcomes as well as the generalizability of results achieved at experienced centers.

  18. Quantitative investigation of free radicals in bio-oil and their potential role in condensed-phase polymerization.

    Science.gov (United States)

    Kim, Kwang Ho; Bai, Xianglan; Cady, Sarah; Gable, Preston; Brown, Robert C

    2015-03-01

    We report on the quantitative analysis of free radicals in bio-oils produced from pyrolysis of cellulose, organosolv lignin, and corn stover by EPR spectroscopy. Also, we investigated their potential role in condensed-phase polymerization. Bio-oils produced from lignin and cellulose show clear evidence of homolytic cleavage reactions during pyrolysis that produce free radicals. The concentration of free radicals in lignin bio-oil was 7.5×10(20)  spin g(-1), which was 375 and 138 times higher than free-radical concentrations in bio-oil from cellulose and corn stover. Pyrolytic lignin had the highest concentration in free radicals, which could be a combination of carbon-centered (benzyl radicals) and oxygen-centered (phenoxy radicals) organic species because they are delocalized in a π system. Free-radical concentrations did not change during accelerated aging tests despite increases in molecular weight of bio-oils, suggesting that free radicals in condensed bio-oils are stable.

  19. Radical chemistry of artemisinin

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, Evgenii T; Solodova, S L; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2010-12-29

    The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

  20. Radical chemistry of artemisinin

    Science.gov (United States)

    Denisov, Evgenii T.; Solodova, S. L.; Denisova, Taisa G.

    2010-12-01

    The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

  1. Radical prostatectomy - discharge

    Science.gov (United States)

    ... to 6 months. You will learn exercises (called Kegel exercises) that strengthen the muscles in your pelvis. ... Radical prostatectomy Retrograde ejaculation Urinary incontinence Patient Instructions Kegel exercises - self-care Suprapubic catheter care Urinary catheters - ...

  2. A new approach to synthesis of benzyl cinnamate: Optimization by response surface methodology.

    Science.gov (United States)

    Zhang, Dong-Hao; Zhang, Jiang-Yan; Che, Wen-Cai; Wang, Yun

    2016-09-01

    In this work, the new approach to synthesis of benzyl cinnamate by enzymatic esterification of cinnamic acid with benzyl alcohol is optimized by response surface methodology. The effects of various reaction conditions, including temperature, enzyme loading, substrate molar ratio of benzyl alcohol to cinnamic acid, and reaction time, are investigated. A 5-level-4-factor central composite design is employed to search for the optimal yield of benzyl cinnamate. A quadratic polynomial regression model is used to analyze the experimental data at a 95% confidence level (P<0.05). The coefficient of determination of this model is found to be 0.9851. Three sets of optimum reaction conditions are established, and the verified experimental trials are performed for validating the optimum points. Under the optimum conditions (40°C, 31mg/mL enzyme loading, 2.6:1 molar ratio, 27h), the yield reaches 97.7%, which provides an efficient processes for industrial production of benzyl cinnamate.

  3. Molecular Interaction Studies of Benzyl Alcohols with Methacrylates in Carbon Tetrachloride using Frequency Domain Technique

    Directory of Open Access Journals (Sweden)

    S. Radhakrishnan

    2016-08-01

    Full Text Available The dielectric relaxation of benzyl alcohol substitutents (benzyl alcohol, m-methylbenzyl alcohol and m-nitrobenzyl alcohol with methyl methacrylate and butyl methacrylate in dilute solution of carbon tetrachloride is measured at 9.37 GHz using Frequency domain (X-band technique. Different dielectric parameters like dielectric constant (ε׳, dielectric loss factor (ε״ at Microwave frequency, static dielectric constant (ε0 and dielectric constant at infinite dilution (ε∞ at optical frequency have been determined. From the measured dielectric data, the relaxation time (t calculated using Higasi method and activation energies (∆Ft and ∆Fη have been determined. All the dielectric parameters that are vary with the substitutent change in benzyl alcohol andchain length of acrylic esters. Suggests that, the proton donating ability is varying with the substitution of benzyl alcohol and proton accepting ability is varying with the chain length of acrylic esters. The relaxation time and molar free energy activation of 1:1 molar ratio is greater than other higher molar ratios (i.e. 3:1, 2:1, 1:2, 1:3 confirm that the existence of most likely 1:1 complex formation between the studied systems and also complex formation formed between free hydroxyl group of substituted benzyl alcohols and carbonyl group of acrylic esters (MMA and EMA.

  4. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  5. Carbocations generated under stable conditions by ionization of matrix-Isolated radicals: the allyl and benzyl cations

    OpenAIRE

    Mišić, Vladimir; Piech, Krzysztof; Bally, Thomas

    2013-01-01

    Carbocations are crucial intermediates in many chemical reactions; hence, considerable effort has gone into investigating their structures and properties, for example, in superacids, in salts, or in the gas phase. However, studies of the vibrational structure of carbocations are not abundant, because their infrared spectra are difficult to obtain in superacids or salts (where furthermore the cations may be perturbed by counterions), and the generation of gas-phase carbocations in discharges u...

  6. Controlled Radical Polymerisation of Styrene in the Presence of Lithium Molybdate(V) Complexes and Benzylic Halides

    NARCIS (Netherlands)

    Koten, G. van; Brandts, J.A.M.; Geijn, P. van de; Faassen, E.E.H. van; Boersma, J.

    1999-01-01

    The new lithium molybdate(V) complexes [LiMo(NAr){2}(C-N)R] (C-N=C{6}H{4}(CH{2}NMe{2})-2; R=(C-N) (5), Me (6), CH{2}SiMe{3} (7), p-tolyl (8)), have been generated in situ from reaction of the corresponding molybdenum(VI) complexes [Mo(NAr){2}(C-N)R] (C-N=C{6}H{4}(CH{2}NMe{2})-2; R=(C-N) (1), Me (2),

  7. Synthesis, Anticancer and Antibacterial Activity of Salinomycin N-Benzyl Amides

    Directory of Open Access Journals (Sweden)

    Michał Antoszczak

    2014-11-01

    Full Text Available A series of 12 novel monosubstituted N-benzyl amides of salinomycin (SAL was synthesized for the first time and characterized by NMR and FT-IR spectroscopic methods. Molecular structures of three salinomycin derivatives in the solid state were determined using single crystal X-ray method. All compounds obtained were screened for their antiproliferative activity against various human cancer cell lines as well as against the most problematic bacteria strains such as methicillin-resistant Staphylococcus aureus (MRSA and Staphylococcus epidermidis (MRSE, and Mycobacterium tuberculosis. Novel salinomycin derivatives exhibited potent anticancer activity against drug-resistant cell lines. Additionally, two N-benzyl amides of salinomycin revealed interesting antibacterial activity. The most active were N-benzyl amides of SAL substituted at -ortho position and the least anticancer active derivatives were those substituted at the -para position.

  8. Synthesis, anticancer and antibacterial activity of salinomycin N-benzyl amides.

    Science.gov (United States)

    Antoszczak, Michał; Maj, Ewa; Napiórkowska, Agnieszka; Stefańska, Joanna; Augustynowicz-Kopeć, Ewa; Wietrzyk, Joanna; Janczak, Jan; Brzezinski, Bogumil; Huczyński, Adam

    2014-11-25

    A series of 12 novel monosubstituted N-benzyl amides of salinomycin (SAL) was synthesized for the first time and characterized by NMR and FT-IR spectroscopic methods. Molecular structures of three salinomycin derivatives in the solid state were determined using single crystal X-ray method. All compounds obtained were screened for their antiproliferative activity against various human cancer cell lines as well as against the most problematic bacteria strains such as methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE), and Mycobacterium tuberculosis. Novel salinomycin derivatives exhibited potent anticancer activity against drug-resistant cell lines. Additionally, two N-benzyl amides of salinomycin revealed interesting antibacterial activity. The most active were N-benzyl amides of SAL substituted at -ortho position and the least anticancer active derivatives were those substituted at the -para position.

  9. Oxidation of benzyl alcohol by K2FeO4 to benzaldehyde over zeolites

    Science.gov (United States)

    Wang, Yuan-Yuan; Song, Hua; Song, Hua-Lin; Jin, Zai-Shun

    2016-10-01

    A novel and green procedure for benzaldehyde synthesis by potassium ferrate oxidation of benzyl alcohol employing zeolite catalysts was studied. The prepared oxidant was characterized by SEM and XRD. The catalytic activity of various solid catalysts was studied using benzyl alcohol as a model compound. USY was found to be a very efficient catalyst for this particular oxidation process. Benzaldehyde yields up to 96.0% could be obtained at the following optimal conditions: 0.2 mL of benzyl alcohol, 4 mmol of K2FeO4, 0.5 g of USY zeolite; 20 mL of cyclohexene, 0.3 mL of acetic acid (36 wt %), 30°C temperature, 4 h reaction time.

  10. Synthesis and tunability of highly electron-accepting, N-benzylated "phosphaviologens".

    Science.gov (United States)

    Stolar, Monika; Borau-Garcia, Javier; Toonen, Mark; Baumgartner, Thomas

    2015-03-11

    We report a structure-property study on phosphoryl-bridged viologen analogues with a remarkably low reduction threshold. Utilizing different benzyl groups for N-quaternization, we were able to confirm the p-benzyl substituent effect on the electronic tunability of the system while maintaining the characteristic chromic response of viologens with two fully reversible one-electron reductions. Due to the considerably increased electron-acceptor properties of the phosphoryl-bridged bipyridine precursor, N-benzylation was found to be very challenging and required the development of new synthetic strategies toward the target viologen species. This study also introduces a new and convenient way for the anion exchange of viologen systems by utilizing methyl triflate. Finally, the practical utility of the new species was verified in simplified proof-of-concept electrochromic devices.

  11. Structure-activity relationship of dopaminergic halogenated 1-benzyl-tetrahydroisoquinoline derivatives.

    Science.gov (United States)

    El Aouad, Noureddine; Berenguer, Inmaculada; Romero, Vanessa; Marín, Paloma; Serrano, Angel; Andujar, Sebastián; Suvire, Fernando; Bermejo, Almudena; Ivorra, M Dolores; Enriz, Ricardo D; Cabedo, Nuria; Cortes, Diego

    2009-11-01

    Two series of halogenated 1-benzyl-7-chloro-6-hydroxy-tetrahydroisoquinolines were prepared to explore the influence of each series on the affinity for dopamine receptors. All the compounds displayed a high affinity for D(1)-like and/or D(2)-like dopamine receptors in striatal membranes, although they were unable to inhibit [(3)H]-dopamine uptake in striatal synaptosomes. The halogen placed on the benzylic ring in 1-benzyl-THIQs, compounds of the series 1, 2'-bromobenzyl derivatives with K(i) values into the nanomolar range, and the series 2, 2',4'-dichlorobenzyl-THIQ homologues, proves to be an important factor to modulate affinity at dopamine receptor.

  12. Solvent-free alkylation of dimethyl malonate using benzyl alcohols catalyzed by FeCl3/SiO2

    Institute of Scientific and Technical Information of China (English)

    Mohammad Reza Shushizadeh; Masumeh Kiany

    2009-01-01

    Activated methylene compound such as dimethyl malonate reacted readily with benzylic alcohols in the presence of ferric chloride/silica gel mixture(FeCl3/SiO2)under microwave irradiation to produce benzylic derivative of dimethyl malonate in high yields in solvent-free condition.

  13. Application of Magnetic Dicationic Ionic Liquid Phase Transfer Catalyst in Nuclophilic Substitution Reactions of Benzyl Halids in Water

    OpenAIRE

    Manouchehr Aghajeri; Ali Reza Kiasat; Bijan Mombeni Goodajdar

    2016-01-01

    magnetic dicationic ionic liquid (MDIL) was successfully prepared and evaluated as phase-transfer catalyst for nucleophilic substitution reactions. The reactions was occurred in water and furnished the corresponding benzyl derivatives in high yields. No evidence for the formation of by-product for example benzyl alcohol of the reaction was observed and the products were obtained in pure form without further purification.

  14. Experimental Determination and Modeling of the Phase Behavior for the Selective Oxidation of Benzyl Alcohol in Supercritical CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Beier, Matthias Josef; Grunwaldt, Jan-Dierk

    2011-01-01

    In this study the phase behavior of mixtures relevant to the selective catalytic oxidation of benzyl alcohol to benzaldehyde by molecular oxygen in supercritical CO2 is investigated. Initially, the solubility of N2 in benzaldehyde as well as the dew points of CO2–benzyl alcohol–O2 and CO2...

  15. Therapeutic Agents in Acne Vulgaris: Part II. D-Alpha Amino Benzyl Penicillin, Erythromycin and Sulfadimethoxine.

    Science.gov (United States)

    Stewart, W D; Maddin, S; Nelson, A J; Danto, J L

    1965-06-26

    A total of 379 patients with pustular and cystic acne vulgaris were selected for study in three groups. Each group was assigned one of the following medications: benzyl penicillin, erythromycin, sulfadimethoxine, or placebo; these were to be compared with tetracycline, a medication whose effectiveness was previously demonstrated in this type of acne. The study revealed a larger number of favourable responses to tetracycline and erythromycin than to sulfadimethoxine. Sulfadimethoxine, however, produced a greater number of favourable responses than did the benzyl penicillin or the placebo; the last-named had equivalent results.

  16. Efficient oxidation of benzyl alcohol with heteropolytungstate as reaction-controlled phase-transfer catalyst

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the properties of reaction-controlled phasetransfer catalysis, and they had excellent catalytic ability to the oxidation of benzyl alcohol. No other by-products were detected by gas chromatography. Once the hydrogen peroxide was consumed completely, the catalyst precipitated from solvent, and the results of the catalyst recycle showed that the catalyst had high stability.

  17. Catalyst system and process for benzyl ether fragmentation and coal liquefaction

    Science.gov (United States)

    Zoeller, Joseph Robert

    1998-04-28

    Dibenzyl ether can be readily cleaved to form primarily benzaldehyde and toluene as products, along with minor amounts of bibenzyl and benzyl benzoate, in the presence of a catalyst system comprising a Group 6 metal, preferably molybdenum, a salt, and an organic halide. Although useful synthetically for the cleavage of benzyl ethers, this cleavage also represents a key model reaction for the liquefaction of coal; thus this catalyst system and process should be useful in coal liquefaction with the advantage of operating at significantly lower temperatures and pressures.

  18. Benzyl alcohol increases voluntary ethanol drinking in rats.

    Science.gov (United States)

    Etelälahti, T J; Eriksson, C J P

    2014-09-01

    The anabolic steroid nandrolone decanoate has been reported to increase voluntary ethanol intake in Wistar rats. In recent experiments we received opposite results, with decreased voluntary ethanol intake in both high drinking AA and low drinking Wistar rats after nandrolone treatment. The difference between the two studies was that we used pure nandrolone decanoate in oil, whereas in the previous study the nandrolone product Deca-Durabolin containing benzyl alcohol (BA) was used. The aims of the present study were to clarify whether the BA treatment could promote ethanol drinking and to assess the role of the hypothalamic-pituitary-adrenal-gonadal axes (HPAGA) in the potential BA effect. Male AA and Wistar rats received subcutaneously BA or vehicle oil for 14 days. Hereafter followed a 1-week washout and consecutively a 3-week voluntary alcohol consumption period. The median (± median absolute deviation) voluntary ethanol consumption during the drinking period was higher in BA-treated than in control rats (4.94 ± 1.31 g/kg/day vs. 4.17 ± 0.31 g/kg/day, p = 0.07 and 1.01 ± 0.26 g/kg/day vs. 0.38 ± 0.27 g/kg/day, p = 0.05, for AA and Wistar rats, respectively; combined effect p < 0.01). The present results can explain the previous discrepancy between the two nandrolone studies. No significant BA effects on basal and ethanol-mediated serum testosterone and corticosterone levels were observed in blood samples taken at days 1, 8 and 22. However, 2h after ethanol administration significantly (p = 0.02) higher frequency of testosterone elevations was detected in high drinking AA rats compared to low drinking Wistars, which supports our previous hypotheses of a role of testosterone elevation in promoting ethanol drinking. Skin irritation and dermatitis were shown exclusively in the BA-treated animals. Altogether, the present results indicate that earlier findings obtained with Deca-Durabolin containing BA need to be re-evaluated.

  19. Gangs, Terrorism, and Radicalization

    Directory of Open Access Journals (Sweden)

    Scott Decker

    2011-01-01

    Full Text Available What can street gangs tell us about radicalization and extremist groups? At first glance, these two groups seem to push the boundaries of comparison. In this article, we examine the important similarities and differences across criminal, deviant, and extremist groups. Drawing from research on street gangs, this article explores issues such as levels of explanation,organizational structure, group process, and the increasingly important role of technology and the Internet in the context of radicalization. There are points of convergence across these groups, but it is important to understand the differences between these groups. This review finds little evidence to support the contention that American street gangs are becoming increasingly radicalized. This conclusion is based largely on organizational differences between gangs and terror groups.

  20. Sexuality Following Radical Prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Serefoglu, Ege C; Albersen, Maarten;

    2017-01-01

    INTRODUCTION: Radical prostatectomies can result in urinary incontinence and sexual dysfunction. Traditionally, these issues have been studied separately, and the sexual problem that has received the most focus has been erectile dysfunction. AIM: To summarize the literature on sexually related side...... effects and their consequences after radical prostatectomy and focus on the occurrence and management of problems beyond erectile dysfunction. METHODS: The literature on sexuality after radical prostatectomy was reviewed through a Medline search. Original research using quantitative and qualitative...... methodologies was considered. Priority was given to studies exploring aspects of sexuality other than erectile function. MAIN OUTCOME MEASURES: The prevalence, predictive factors, and management of post-prostatectomy sexual problems beyond erectile dysfunction. RESULTS: Most patients will develop urinary...

  1. Crystal structure of benzyl (E)-2-(3,4-di-meth-oxy-benzyl-idene)hydrazine-1-carbodi-thio-ate.

    Science.gov (United States)

    Tan, Yew-Fung; Break, Mohammed Khaled Bin; Tahir, M Ibrahim M; Khoo, Teng-Jin

    2015-02-01

    The title compound, C17H18N2O2S2, synthesized via a condensation reaction between S-benzyl di-thio-carbazate and 3,4-di-meth-oxy-benzaldehyde, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. Both mol-ecules have an L-shape but differ in the orientation of the benzyl ring with respect to the 3,4-di-meth-oxy-benzyl-idine ring, this dihedral angle is 65.59 (8)° in mol-ecule A and 73.10 (8)° in mol-ecule B. In the crystal, the A and B mol-ecules are linked via pairs of N-H⋯S hydrogen bonds, forming dimers with an R 2 (2)(8) ring motif. The dimers are linked via pairs of C-H⋯O hydrogen bonds, giving inversion dimers of dimers. These units are linked by C-H⋯π inter-actions, forming ribbons propagating in the [100] direction.

  2. Beyond Radical Educational Cynicism.

    Science.gov (United States)

    Wood, George H.

    1982-01-01

    An alternative is presented to counter current radical arguments that the schools cannot bring about social change because they are instruments of capitalism. The works of Samuel Bowles, Herbert Gintis, and Louis Althusser are discussed. Henry Giroux's "Ideology, Culture and the Process of Schooling" provides an alternative to cynicism.…

  3. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  4. Electromeric rhodium radical complexes

    NARCIS (Netherlands)

    Puschmann, F.F.; Harmer, J.; Stein, D.; Rüegger, H.; de Bruin, B.; Grützmacher, H.

    2010-01-01

    Radical changes: One single P-Rh-P angle determines whether the odd electron in the paramagnetic complex [Rh(trop2PPh)(PPh3)] is delocalized over the whole molecule (see picture, blue) or is localized on the P—Rh unit (red). The two energetically almost degenerate electromers exist in a fast equilib

  5. Violent Radicalization in Europe

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja

    2010-01-01

    When, why, and how do people living in a democracy become radicalized to the point of being willing to use or directly support the use of terrorist violence against fellow citizens? This question has been at the center of academic and public debate over the past years as terrorist attacks...

  6. Radical School Reform.

    Science.gov (United States)

    Gross, Beatrice, Ed.; Gross, Ronald, Ed.

    This book provides a comprehensive examination of the nature of the school crisis and the ways in which radical thinkers and educators are dealing with it. Excerpts from the writings of Jonathan Kozol, John Holt, Kenneth Clark, and others are concerned with the realities of education in ghettos and suburbs. Paul Goodman, Marshall McLuhan, Sylvia…

  7. Homegrown religious radicalization

    DEFF Research Database (Denmark)

    Khawaja, Iram

    and their families. Existing literature and ways of thinking about the social psychological process of radicalization will be reviewed, such as social identity theory and transformative learning theory, and a theoretical framework based on a focus on belonging, recognition and the sense of community will be proposed...

  8. On Radical Feminism

    Institute of Scientific and Technical Information of China (English)

    翟良锴

    2015-01-01

    <正>All men are created equal.For centuries,human have been struggling for their rights.Women,as a special social force,are fighting vigorously for their equal rights with men.According to an introduction to feminism,there are three main types of feminism:socialist,reformist and radical(Feminism 101).In order

  9. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Energy Technology Data Exchange (ETDEWEB)

    Chenavas, P. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  10. Effect of cotton pectin content and bioscouring on alkyl-dimethyl-benzyl-ammonium chloride adsorption

    Science.gov (United States)

    Our previous research has shown both the rate and the total amount of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) exhausted from a bulk solution of ADBAC are significantly greater for greige cotton nonwovens than cotton nonwovens that have been both scoured and bleached. The presence of pectin ...

  11. Adsorption of alkyl-dimethyl-benzyl-ammonium chloride on differently pretreated nonwoven cotton substrate

    Science.gov (United States)

    The adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on greige, alkaline scoured, and bleached nonwoven cotton fabrics was investigated at varying surfactant concentrations and liquor ratios using UV-vis absorption spec...

  12. Extraction of toluene, o-xylene from heptane and benzyl alcohol from toluene with aqueous cyclodextrins

    NARCIS (Netherlands)

    Meindersma, G.W.; Schoonhoven, van T.; Kuzmanovic, B.; Haan, de A.B.

    2006-01-01

    The separation of aromatic compounds (toluene and o-xylene) from heptane and of benzyl alcohol from toluene with aqueous solutions of cyclodextrins has been experimentally investigated, because cyclodextrins and its derivatives can selectively incorporate several organic compounds, whereas the separ

  13. Support influences in the Pd-catalyzed racemization and dynamic kinetic resolution of chiral benzylic amines

    NARCIS (Netherlands)

    Parvulescu, A.N.; Jacobs, P.A.; De Vos, D.E.

    2009-01-01

    The acid–base properties of the supports for Pd catalysts strongly affect their performance in racemization and dynamic kinetic resolution (DKR) of chiral benzylic amines. The need for a basic support was proven by comparing the racemization results obtained for Pd on silica, on LDH (layered double

  14. A Case of Abnormal Bishler-Napieralski Cyclization Reaction, Leading to Form Benzyl Oxazole Derivatives

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A benzyl oxazole compound 3 was obtained with an excellent yield of 90% when N-acetyl-(2?methoxy-4?5?methylenedioxy)-phenylalanine methyl ester 1 was refluxed in POCl3 /benzene. However, the anticipated product 3,4-dihydroisoquinoline-3-carboxylic acid methyl ester 2 could not be found. The mechanism was discussed in this article.

  15. Pharmacokinetics in Elderly Women of Benzyl Alcohol From an Oil Depot

    NARCIS (Netherlands)

    Kalicharan, Raween; El Amrani, Mohsin; Schot, Peter; Vromans, Herman|info:eu-repo/dai/nl/073088803

    2016-01-01

    Pharmaceutical oil depots are meant to release active substances at a sustained rate. Most of these depots contain benzyl alcohol (BOH) to facilitate the production and administration. Because BOH changes the solubility of components in both the body fluid and the oil formulation, it is relevant to

  16. Study of the antibacterial and antifungal activities of synthetic benzyl bromides, ketones, and corresponding chalcone derivatives

    Science.gov (United States)

    Shakhatreh, Muhamad Ali K; Al-Smadi, Mousa L; Khabour, Omar F; Shuaibu, Fatima A; Hussein, Emad I; Alzoubi, Karem H

    2016-01-01

    Several applications of chalcones and their derivatives encouraged researchers to increase their synthesis as an alternative for the treatment of pathogenic bacterial and fungal infections. In the present study, chalcone derivatives were synthesized through cross aldol condensation reaction between 4-(N,N-dimethylamino)benzaldehyde and multiarm aromatic ketones. The multiarm aromatic ketones were synthesized through nucleophilic substitution reaction between 4-hydroxy acetophenone and benzyl bromides. The benzyl bromides, multiarm aromatic ketones, and corresponding chalcone derivatives were evaluated for their activities against eleven clinical pathogenic Gram-positive, Gram-negative bacteria, and three pathogenic fungi by the disk diffusion method. The minimum inhibitory concentration was determined by the microbroth dilution technique. The results of the present study demonstrated that benzyl bromide derivatives have strong antibacterial and antifungal properties as compared to synthetic chalcone derivatives and ketones. Benzyl bromides (1a and 1c) showed high ester activity against Gram-positive bacteria and fungi but moderate activity against Gram-negative bacteria. Therefore, these compounds may be considered as good antibacterial and antifungal drug discovery. However, substituted ketones (2a–b) as well as chalcone derivatives (3a–c) showed no activity against all the tested strains except for ketone (2c), which showed moderate activity against Candida albicans. PMID:27877017

  17. Design, synthesis and biological activity of novel peptidyl benzyl ketone FVIIa inhibitors

    DEFF Research Database (Denmark)

    Storgaard, Morten; Henriksen, Signe Teuber; Zaragoza, Florencio

    2011-01-01

    Herein is described the synthesis of a novel class of peptidyl FVIIa inhibitors having a C-terminal benzyl ketone group. This class is designed to be potentially suitable as stabilization agents of liquid formulations of rFVIIa, which is a serine protease used for the treatment of hemophilia A an...

  18. Homocoupling of benzyl halides catalyzed by POCOP-nickel pincer complexes

    KAUST Repository

    Chen, Tao

    2012-08-01

    Two types of POCOP-nickel(II) pincer complexes were prepared by mixing POCOP pincer ligands and NiX 2 in toluene at reflux. The resulting nickel complexes efficiently catalyze the homocoupling reactions of benzyl halides in the presence of zinc. The coupled products were obtained in excellent to quantitative yields. © 2012 Elsevier Ltd. All rights reserved.

  19. The Synthesis and Methanolysis of Benzyl Tosylates: An Advanced Organic Chemistry Laboratory Experiment.

    Science.gov (United States)

    Garst, Michael E.; Gribble, Gordon W.

    1984-01-01

    Describes a series of experiments (requiring six hours/week for six to eight weeks) involving the synthesis and methanolysis of substituted benzyl tosylates. The experiments provide students with experiences in kinetic data manipulation and an introduction and firm basis for structure-activity relationships and solvent effects in organic…

  20. "Decarbonization" of an imino N-heterocyclic carbene via triple benzyl migration from hafnium

    Science.gov (United States)

    An imino N-heterocyclic carbene underwent three sequential benzyl migrations upon reaction with tetrabenzylhafnium, resulting in complete removal of the carbene carbon from the ligand. The resulting eneamido-amidinato hafnium complex showed alkene polymerization activity comparable to that of a prec...

  1. Effects of benzyl isothiocyanate on the reproduction of Meloidogyne incognita on Glycine max and Capsicum annuum

    Science.gov (United States)

    Reproduction of Meloidogyne incognita on Capsicum annuum or Glycine max was suppressed when infective juveniles (J2) were exposed to 0.03 millimolar benzyl isothiocyanate (BITC) for 2hr prior to inoculation of the host. Infectivity assessed by gall index was significantly reduced on both G. max (co...

  2. The retro Grignard addition reaction revisited: the reversible addition of benzyl reagents to ketones

    DEFF Research Database (Denmark)

    Christensen, Stig Holden; Holm, Torkil; Madsen, Robert

    2014-01-01

    The Grignard addition reaction is known to be a reversible process with allylic reagents, but so far the reversibility has not been demonstrated with other alkylmagnesium halides. By using crossover experiments it has been established that the benzyl addition reaction is also a reversible transfo...

  3. Inhibition of a Gold-Based Catalyst in Benzyl Alcohol Oxidation: Understanding and Remediation

    NARCIS (Netherlands)

    Skupien, E.; Berger, R.J.; Santos, V.P.; Gascon, J.; Makkee, M.; Kreutzer, M.T.; Kooyman, P.J.; Moulijn, J.A.; Kapteijn, F.

    2014-01-01

    Benzyl alcohol oxidation was carried out in toluene as solvent, in the presence of the potentially inhibiting oxidation products benzaldehyde and benzoic acid. Benzoic acid, or a product of benzoic acid, is identified to be the inhibiting species. The presence of a basic potassium salt (K2CO3 or KF)

  4. Unusual C-C bond cleavage in the formation of amine-bis(phenoxy) group 4 benzyl complexes: Mechanism of formation and application to stereospecific polymerization

    KAUST Repository

    Gowda, Ravikumar R.

    2014-08-11

    Group 4 tetrabenzyl compounds MBn4 (M = Zr, Ti), upon protonolysis with an equimolar amount of the tetradentate amine-tris(phenol) ligand N[(2,4-tBu2C6H2(CH 2)OH]3 in toluene from -30 to 25 °C, unexpectedly lead to amine-bis(phenoxy) dibenzyl complexes, BnCH2N[(2,4- tBu2C6H2(CH2)O] 2MBn2 (M = Zr (1), Ti (2)) in 80% (1) and 75% (2) yields. This reaction involves an apparent cleavage of the >NCH2-ArOH bond (loss of the phenol in the ligand) and formation of the >NCH 2-CH2Bn bond (gain of the benzyl group in the ligand). Structural characterization of 1 by X-ray diffraction analysis confirms that the complex formed is a bis(benzyl) complex of Zr coordinated by a newly derived tridentate amine-bis(phenoxy) ligand arranged in a mer configuration in the solid state. The abstractive activation of 1 and 2 with B(C6F 5)3·THF in CD2Cl2 at room temperature generates the corresponding benzyl cations {BnCH2N[(2,4- tBu2C6H2(CH2)O] 2MBn(THF)}+[BnB(C6F5) 3]- (M = Zr (3), Ti, (4)). These cationic complexes, along with their analogues derived from (imino)phenoxy tri- and dibenzyl complexes, [(2,6-iPr2C6H3)N=C(3,5- tBu2C6H2)O]ZrBn3 (5) and [2,4-Br2C6H2(O)(6-CH2(NC 5H9))CH2N=CH(2-adamantyl-4-MeC 6H2O)]ZrBn2 (6), have been found to effectively polymerize the biomass-derived renewable β-methyl-α-methylene- γ-butyrolactone (βMMBL) at room temperature into the highly stereoregular polymer PβMMBL with an isotacticity up to 99% mm. A combined experimental and DFT study has yielded a mechanistic pathway for the observed unusual C-C bond cleavage in the present protonolysis reaction between ZrBn4 and N[(2,4-tBu2C 6H2(CH2)OH]3 for the formation of complex 1, which involves the benzyl radical and the Zr(III) species, resulting from thermal and photochemical decomposition of ZrBn4, followed by a series of reaction sequences consisting of protonolysis, tautomerization, H-transfer, oxidation, elimination, and radical coupling. © 2014 American Chemical Society.

  5. BPIC: A novel anti-tumor lead capable of inhibiting inflammation and scavenging free radicals.

    Science.gov (United States)

    Li, Shan; Wang, Yuji; Zhao, Ming; Wu, Jianhui; Peng, Shiqi

    2015-03-01

    Inflammation has a critical role in the tumor progression, free radical damage can worse the status of patients in cancer condition. The anti-cancer agents capable of inhibiting inflammation and scavenging free radicals attract a lot of our interest. Aimed at the discovery of such anti-tumor agent, a novel intercalator, benzyl 1-[4-hydroxy-3-(methoxycarbonyl)-phenyl-9H-pyrido[3,4-b]indole-3-carboxylate (BPIC) was presented. The docking investigation of BPIC and doxorubicin towards the DNA (PDB ID: 1NAB) gave equal score and similar feature. The anti-proliferation assay of 8 cancer cells identified S180 cells had equal sensitivity to BPIC and doxorubicin. The anti-tumor assay defined the efficacy of BPIC been 2 folds higher than that of doxorubicin. At 1μmol/kg of dose BPIC effectively inhibited xylene-induced ear edema and decreased the plasma TNF-α and IL-8 of the mice. BPIC scavenged ∙OH, ∙O2(-) and NO free radicals in a concentration dependent manner and NO free radicals had the highest sensitivity. BPIC could be a novel anti-tumor lead capable of simultaneously inhibiting inflammation and scavenging free radicals.

  6. Synthetic scope, computational chemistry and mechanism of a base induced 5-endo cyclization of benzyl alkynyl sulfides

    Science.gov (United States)

    Motto, John M.; Castillo, Álvaro; Montemayer, Laura K.; Sheepwash, Erin E.

    2011-01-01

    We present an experimental and computational study of the reaction of aryl substituted benzyl 1-alkynyl sulfides with potassium alkoxide in acetonitrile, which produces 2-aryl 2,3-dihydrothiophenes in poor to good yields. The cyclization is most efficient with electron withdrawing groups on the aromatic ring. Evidence indicates there is rapid exchange of protons and tautomerism of the alkynyl unit prior to cyclization. Theoretical calculations were also conducted to help rationalize the base induced 5-endo cyclization of benzyl 1-propynyl sulfide (1a). The potential energy surface was calculated for the formation of 2,3-dihydrothiophene in a reaction of benzyl 1-propynyl sulfide (1a) with potassium methoxide. Geometries were optimized with CAM-B3LYP/6-311+G(d,p) in acetonitrile with the CPCM solvent model. It is significant that the benzyl propa-1,2-dien-1-yl sulfane (6) possessed a lower benzylic proton affinity than the benzyl prop-2-yn-1-yl sulfane (8) thus favoring the base induced reaction of the former. From benzyl(propa-1,2-dien-1-yl sulfane (6), 2,3-dihydrothiophene can be formed via a conjugate base that undergoes 5-endo-trig cyclization followed by a protonation step. PMID:21442022

  7. Investigation of comparative efficacy of eugenol and benzyl benzoate in therapy of sheep mange

    Directory of Open Access Journals (Sweden)

    Jezdimirović Milanka

    2010-01-01

    Full Text Available The acaricide efficacy, tolerance and safety of eugenol (10 and 20 % in the treatment of sarcoptic mange in sheep have been investigated. The results were compared with those corresponding for benzyl benzoate (25 %, which was applied to sheep in the same way. The treatment was applied on sheep three times in one-week intervals. Skin scrapings were sampled seven days after each treatment, as well as twenty-eight days following the third one. The changes on the skin were quantified and the mean recovery response (MRR was calculated. The clinical efficacy was assessed according to the MRR and the number of mites in the samples. Following the first treatment 10%eugenol was not significantly less efficacious in comparison with the higher concentration. Having been applied twice 20% eugenol was significantly more efficacious when compared to the lower concentration, which remained the same seven and twenty-eight days after the third application. The efficacy of 10% eugenol in the therapy of mange was significantly higher in comparison with benzyl benzoate following one, two or three administrations. The efficacy of benzyl benzoate four weeks after the third treatment was still significantly lower in comparison with 10% eugenol. The efficacy of 20% eugenol was significantly higher in comparison with its lower concentration as well as that of benzyl benzoate, following the second, and seven and twenty-eight days after the third one. No signs of local or systemic intolerance were observed in sheep treated with either 10 or 20% eugenol, or 25 % benzyl benzoate. .

  8. Probability and radical behaviorism

    Science.gov (United States)

    Espinosa, James M.

    1992-01-01

    The concept of probability appears to be very important in the radical behaviorism of Skinner. Yet, it seems that this probability has not been accurately defined and is still ambiguous. I give a strict, relative frequency interpretation of probability and its applicability to the data from the science of behavior as supplied by cumulative records. Two examples of stochastic processes are given that may model the data from cumulative records that result under conditions of continuous reinforcement and extinction, respectively. PMID:22478114

  9. Probability and radical behaviorism

    OpenAIRE

    Espinosa, James M.

    1992-01-01

    The concept of probability appears to be very important in the radical behaviorism of Skinner. Yet, it seems that this probability has not been accurately defined and is still ambiguous. I give a strict, relative frequency interpretation of probability and its applicability to the data from the science of behavior as supplied by cumulative records. Two examples of stochastic processes are given that may model the data from cumulative records that result under conditions of continuous reinforc...

  10. Radical chic, javisst!

    NARCIS (Netherlands)

    Hartle, J.F.

    2012-01-01

    Det är lätt att raljera över engagerade människor, i synnerhet när engagemanget framstår som ytligt och chict snarare än grundläggande och autentiskt. Men vad ligger bakom ett sådant avfärdande? Johan Frederik Hartle läser om Tom Wolfes klassiska essä "Radical Chic" och visar hur Wolfe −− genom att

  11. Women and radicalization

    OpenAIRE

    Badran, Margot

    2006-01-01

    The paper focuses on women and radicalization within the context of Muslim societies (majority, minority, and half Muslim) societies and groups, mainly in Asia and Africa. The basic argument advanced in this paper is that Islamic feminism with its gender-egalitarian discourse and practices has a major role to play in the empowerment of Muslim women—and of men and society as a whole—and should be brought to bear in devising policy, strategy, and tools.

  12. THERMOCHEMISTRY OF HYDROCARBON RADICALS

    Energy Technology Data Exchange (ETDEWEB)

    Kent M. Ervin, Principal Investigator

    2004-08-17

    Gas phase negative ion chemistry methods are employed to determine enthalpies of formation of hydrocarbon radicals that are important in combustion processes and to investigate the dynamics of ion-molecule reactions. Using guided ion beam tandem mass spectrometry, we measure collisional threshold energies of endoergic proton transfer and hydrogen atom transfer reactions of hydrocarbon molecules with negative reagent ions. The measured reaction threshold energies for proton transfer yield the relative gas phase acidities. In an alternative methodology, competitive collision-induced dissociation of proton-bound ion-molecule complexes provides accurate gas phase acidities relative to a reference acid. Combined with the electron affinity of the R {center_dot} radical, the gas phase acidity yields the RH bond dissociation energy of the corresponding neutral molecule, or equivalently the enthalpy of formation of the R{center_dot} organic radical, using equation: D(R-H) = {Delta}{sub acid}H(RH) + EA(R) - IE(H). The threshold energy for hydrogen abstraction from a hydrocarbon molecule yields its hydrogen atom affinity relative to the reagent anion, providing the RH bond dissociation energy directly. Electronic structure calculations are used to evaluate the possibility of potential energy barriers or dynamical constrictions along the reaction path, and as input for RRKM and phase space theory calculations. In newer experiments, we have measured the product velocity distributions to obtain additional information on the energetics and dynamics of the reactions.

  13. [Radical prostatectomy - pro robotic].

    Science.gov (United States)

    Gillitzer, R

    2012-05-01

    Anatomical radical prostatectomy was introduced in the early 1980s by Walsh and Donker. Elucidation of key anatomical structures led to a significant reduction in the morbidity of this procedure. The strive to achieve similar oncological and functional results to this gold standard open procedure but with further reduction of morbidity through a minimally invasive access led to the establishment of laparoscopic prostatectomy. However, this procedure is complex and difficult and is associated with a long learning curve. The technical advantages of robotically assisted surgery coupled with the intuitive handling of the device led to increased precision and shortening of the learning curve. These main advantages, together with a massive internet presence and aggressive marketing, have resulted in a rapid dissemination of robotic radical prostatectomy and an increasing patient demand. However, superiority of robotic radical prostatectomy in comparison to the other surgical therapeutic options has not yet been proven on a scientific basis. Currently robotic-assisted surgery is an established technique and future technical improvements will certainly further define its role in urological surgery. In the end this technical innovation will have to be balanced against the very high purchase and running costs, which remain the main limitation of this technology.

  14. Solid-state conformation of copolymers of ß-benzyl-L-aspartate with L-alanine, L-leucine, L-valine, γ-benzyl-L-glutamate, or ε-carbobenzoxy-L-lysine

    NARCIS (Netherlands)

    Sederel, Willem L.; Bantjes, Adriaan; Feijen, Jan; Anderson, James M.

    1980-01-01

    The solid-state conformation of copolymers of ß-benzyl-L-aspartate [L-Asp(OBzl)] with L-leucine (L-Leu), L-alanine (L-Ala), L-valine (L-Val), γ-benzyl-L-glutamate [L-Glu(OBzl)], or ε-carbobenzoxy-L-lysine (Cbz-L-Lys) has been studied by ir spectroscopy and circular dichroism (CD). The ir spectra in

  15. Synthesis and anticonvulsant activity of 1-substituted benzyl-N-substituted-1, 2, 3-triazole-4-for-mamides

    Institute of Scientific and Technical Information of China (English)

    WANG Junmin; JUN Changsoo; CHAI Kyuyun; KWAK Kyungchell; QUAN Zheshan

    2006-01-01

    Substituted benzyl azids were synthesized through the reaction of substituted benzyl chloride and sodium azid, which subsequently underwent cyclization with ethyl propiolate and amidation to give thirteen 1-substituted benzyl-N-substituted-1, 2, 3-triazole-4-formamide derivatives (3a-3m). The structure of the synthesized compounds was confirmed by IR, 1H-NMR, MS and elemental analysis. Their anticonvulsant activity against maximal electrolshock (MES) induced seizure was tested and the result showed that all these compounds possess anticonvulsant activity in different degrees. Among those, the compounds containing chloro atoms on the phenyl ring were less potent in anticonvulsant activity, while introducing one or two fluorin atoms on benzyl system increased its activity. Furthermore, their activity decreased when there was substituent on the nitrogen atom of carboxamide, and the larger the substituent, the lower the activity.

  16. Highly active and reusable catalyst from Fe-Mg-hydrotalcite anionic clay for Friedel-Crafts type benzylation reactions

    Indian Academy of Sciences (India)

    Vasant R Choudhary; Rani Jha; Pankaj A Choudhari

    2005-11-01

    Fe-Mg-hydrotalcite (Mg/Fe = 3) anionic clay with or without calcination (at 200-800°C) has been used for the benzylation of toluene and other aromatic compounds by benzyl chloride. Hydrotalcite before and after its calcination was characterized for surface area, crystalline phases and basicity. Both the hydrotalcite, particularly after its use in the benzylation reaction, and the catalyst derived from it by its calcination at 200-800°C show high catalytic activity for the benzylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the chlorides and oxides of iron on the catalyst surface.

  17. Benzyl Derivatives with in Vitro Binding Affinity for Human Opioid Receptors and Cannabinoid Receptors from the Fungus Eurotium repens

    Science.gov (United States)

    Bioassay-guided fractionation of the fungus Eurotium repens resulted in the isolation of two benzyl derivatives, repenol A (1) and repenol B (2). Seven known secondary metabolites were also isolated including five benzaldehyde compounds, flavoglaucin (3), tetrahydroauroglaucin (4), dihydroauroglauci...

  18. The facile insertion of β-keto sulfones to arynes: The direct preparation of polysubstituted ortho-keto benzyl sulfones

    Institute of Scientific and Technical Information of China (English)

    Jian Xue; Lu Ling Wu; Xian Huang

    2008-01-01

    One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.

  19. Catalysis of Radical Reactions: A Radical Chemistry Perspective.

    Science.gov (United States)

    Studer, Armido; Curran, Dennis P

    2016-01-04

    The area of catalysis of radical reactions has recently flourished. Various reaction conditions have been discovered and explained in terms of catalytic cycles. These cycles rarely stand alone as unique paths from substrates to products. Instead, most radical reactions have innate chains which form products without any catalyst. How do we know if a species added in "catalytic amounts" is a catalyst, an initiator, or something else? Herein we critically address both catalyst-free and catalytic radical reactions through the lens of radical chemistry. Basic principles of kinetics and thermodynamics are used to address problems of initiation, propagation, and inhibition of radical chains. The catalysis of radical reactions differs from other areas of catalysis. Whereas efficient innate chain reactions are difficult to catalyze because individual steps are fast, both inefficient chain processes and non-chain processes afford diverse opportunities for catalysis, as illustrated with selected examples.

  20. Application of Magnetic Dicationic Ionic Liquid Phase Transfer Catalyst in Nuclophilic Substitution Reactions of Benzyl Halids in Water

    Directory of Open Access Journals (Sweden)

    Manouchehr Aghajeri

    2016-06-01

    Full Text Available magnetic dicationic ionic liquid (MDIL was successfully prepared and evaluated as phase-transfer catalyst for nucleophilic substitution reactions. The reactions was occurred in water and furnished the corresponding benzyl derivatives in high yields. No evidence for the formation of by-product for example benzyl alcohol of the reaction was observed and the products were obtained in pure form without further purification.

  1. Gnosticism and Radical Feminism

    DEFF Research Database (Denmark)

    Cahana, Jonathan

    2016-01-01

    and place demand an explanation; my attempt to do so also takes into account the important differences between the gnostic and the radical feminist postures, notably the latter belief in progress and the former nostalgia for an ungendered era. Both the similarities and the differences, however, may offer...... support for approaching Gnosticism as first and foremost a cultural phenomenon (albeit exhibiting religious “symptoms”), and I attempt to show that such an approach can help to solve the recurrent problem of defining Gnosticism....

  2. Comparison of ivermectin and benzyl benzoate lotion for scabies in Nigerian patients.

    Science.gov (United States)

    Sule, Halima M; Thacher, Tom D

    2007-02-01

    Few studies have compared ivermectin directly with topical agents in developing countries. We compared the effectiveness of oral ivermectin (200 microg/kg) with topical 25% benzyl benzoate and monosulfiram soap in 210 subjects of age 5 to 65 years with scabies. Subjects with persistent lesions after 2 weeks received a second course of treatment. All lesions had resolved after 2 weeks in 77 of 98 (79%) subjects treated with ivermectin and in 60 of 102 (59%) subjects treated topically (P = 0.003). The improvement in severity score was greater in the ivermectin group than in the topical treatment group (P topical treatment group (P = 0.04). Compared with topical benzyl benzoate and monosulfiram in the treatment of scabies, ivermectin was at least as effective and led to more rapid improvement.

  3. The Benzyl Moiety in a Quinoxaline-Based Scaffold Acts as a DNA Intercalation Switch.

    Science.gov (United States)

    Mahata, Tridib; Kanungo, Ajay; Ganguly, Sudakshina; Modugula, Eswar Kalyan; Choudhury, Susobhan; Pal, Samir Kumar; Basu, Gautam; Dutta, Sanjay

    2016-06-27

    Quinoxaline antibiotics intercalate dsDNA and exhibit antitumor properties. However, they are difficult to synthesize and their structural complexity impedes a clear mechanistic understanding of DNA binding. Therefore design and synthesis of minimal-intercalators, using only part of the antibiotic scaffold so as to retain the key DNA-binding property, is extremely important. Reported is a unique example of a monomeric quinoxaline derivative of a 6-nitroquinoxaline-2,3-diamine scaffold which binds dsDNA by two different modes. While benzyl derivatives bound DNA in a sequential fashion, with intercalation as the second event, nonbenzyl derivatives showed only the first binding event. The benzyl intercalation switch provides important insights about molecular architecture which control specific DNA binding modes and would be useful in designing functionally important monomeric quinoxaline DNA binders and benchmarking molecular simulations.

  4. Structural micellar transition for fluorinated and hydrogenated sodium carboxylates induced by solubilization of benzyl alcohol.

    Science.gov (United States)

    González-Pérez, Alfredo; Ruso, Juan M; Prieto, Gerardo; Sarmiento, Félix

    2004-09-28

    The solubility of benzyl alcohol in micellar solutions of sodium octanoate and sodium perfluorooctanoate was studied. From the isotherms of specific conductivity versus molality at different alcohol concentrations, the critical micelle concentration and the degree of ionization of the micelles were determined. The cmc linearly decreases upon increasing the amount of benzyl alcohol present in aqueous solutions with two distinct slopes. This phenomenon was interpreted as a clustering of alcohol molecules above a critical point, around 0.1 mol kg(-1). Attending to the equivalent conductivity versus square root of molality, the presence of a second micellar structure for the fluorinated compound was assumed. The thermodynamic parameters associated with the process of micellization were estimated by applying Motomura's model for binary surfactant mixtures, modified by Pérez-Villar et al. (Colloid Polym. Sci 1990, 268, 965) for the case of alcohol-surfactant solutions. A comparison of the hydrogenated and fluorinated compounds was carried out and discussed.

  5. Flotation of kaolinite and diaspore with hexadecyl dimethyl benzyl ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    HU Yue-hua; OUYANG Kui; CAO Xue-feng; ZHANG Li-min

    2008-01-01

    Tertiary amine was synthesized from fatty amine and formaldehyde. And then the synthesized tertiary amine was used toreact with benzyl chloride to synthesize hexadecyl dimethyl benzyl ammonium chloride (1627) at ambient pressure. Using thesynthesized 1627 as collector, the flotation properties of diaspore and kaolinite were investigated by single mineral and mixedmineral test. The flotation mechanism of diaspore, kaolinite and 1627 was discussed based on FTIR spectra. The results show that themass ratio of aluminum to silicate achieves 15.02 and the recovery of alumina in concentrate is 43.07% using 1627 as a collector. The 1627 is found to be a more effective and a promising collector for reverse flotation to remove aluminum-silicate minerals frombauxite.

  6. Enantiomeric resolution of p-toluenesulfonate of valine benzyl ester by preferential crystallizaion.

    Science.gov (United States)

    Munegumi, Toratane; Wakatsuki, Aiko; Takahashi, Yutaro

    2012-02-01

    Preferential crystallization of amino acid derivatives by seeding a pure enantiomer into racemic amino acid solutions has been studied for many years. However, few examples of valine derivatives have been reported so far. Although there have been some reports using valine hydrogen chloride with preferential crystallization, it is difficult to obtain optical isomers for valine derivatives using preferential crystallization. In this study, repeated preferential crystallization of p-toluenesulfonate valine benzyl ester with a 20% e.e. in 2-propanol gave a 94% e.e. on sonication. Sonication accelerated crystallization rate, but there was not a big difference in e.e. between with and without sonication. However, this research demonstrates the first preferential crystallization of p-toluenesulfonate of valine benzyl esters with an acceleration of crystallization using sonication.

  7. Lipase-catalysed selective deacetylation of phenolic/enolic acetoxy groups in peracetylated benzyl phenyl ketones.

    Science.gov (United States)

    Parmar, V S; Pati, H N; Azim, A; Kumar, R; Himanshu; Bisht, K S; Prasad, A K; Errington, W

    1998-01-01

    Highly chemo- and regioselective de-esterification has been observed in the deacetylation of peracetylated enolic forms of polyphenolic benzyl phenyl ketones by lipase from porcine pancreas (PPL) suspended in tetrahydrofuran (THF). The enzyme selectively deacetylates the enolic acetoxy over the phenolic acetoxy group(s) and continuation of the reaction resulted, in addition the regioselective deacetylation of acetoxy function para to the nuclear carbonyl group.

  8. Carbamate-directed benzylic lithiation for the diastereo- and enantioselective synthesis of diaryl ether atropisomers

    Directory of Open Access Journals (Sweden)

    Abigail Page

    2011-09-01

    Full Text Available Diaryl ethers carrying carbamoyloxymethyl groups may be desymmetrised enantio- and diastereoselectively by the use of the sec-BuLi–(−-sparteine complex in diethyl ether. Enantioselective deprotonation of one of the two benzylic positions leads to atropisomeric products with ca. 80:20 e.r.; an electrophilic quench typically provides functionalised atropisomeric diastereoisomers in up to 97:3 d.r.

  9. Benzyl 2-β-Glucopyranosyloxybenzoate, a New Phenolic Acid Glycoside from Sarcandra glabra

    OpenAIRE

    Xudong Xu; Haifeng Wu; Xiaoru Hu; Shilin Chen; Junshan Yang; Xiaopo Zhang

    2012-01-01

    From the whole plant of Sarcandra glabra, a new phenolic acid glycoside, benzyl 2-β-glucopyranosyloxybenzoate (1), together with seven known compounds including eleutheroside B1 (2), 5-O-caffeoylshikimic acid (3), (–)-(7S, 8R)-dihydrodehydro-diconiferyl alcohol (

  10. Crystal-phase control of molybdenum carbide nanobelts for dehydrogenation of benzyl alcohol.

    Science.gov (United States)

    Li, Zhongcheng; Chen, Chunhui; Zhan, Ensheng; Ta, Na; Li, Yong; Shen, Wenjie

    2014-05-04

    Belt-shaped molybdenum carbides in α- and β-phases were synthesized by reducing and carburizing a nano-sized α-MoO3 precursor with hydrocarbon-hydrogen mixtures at appropriate temperatures; the β-Mo2C nanobelts with a higher fraction of coordinatively unsaturated Mo sites were more active than the α-MoC1-x nanobelts in dehydrogenation of benzyl alcohol to benzaldehyde.

  11. Benzyl Isothiocyanate Inhibits Epithelial-Mesenchymal Transition in Cultured and Xenografted Human Breast Cancer Cells

    OpenAIRE

    Sehrawat, Anuradha; Singh, Shivendra V.

    2011-01-01

    We showed previously that cruciferous vegetable constituent benzyl isothiocyanate (BITC) inhibits growth of cultured and xenografted human breast cancer cells, and suppresses mammary cancer development in a transgenic mouse model. We now demonstrate, for the first time, that BITC inhibits epithelial-to-mesenchymal transition (EMT) in human breast cancer cells. Exposure of estrogen-independent MDA-MB-231 and estrogen-responsive MCF-7 human breast cancer cell lines and a pancreatic cancer cell ...

  12. Linear free energy relationship in reactions between diphenyl amine and benzyl bromides

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2006-05-01

    Rate of reaction between benzyl bromide and diphenyl amine is retarded by electron-donating groups and enhanced by electron-withdrawing groups present on the benzene ring of the substrate. Hammett's reaction constant of the reaction decreases with increase in temperature according to the equation, \\rho = -11.92 + 3.54/ T. Minimal structural effects observed are attributed to the fact that the isokinetic temperature of the reaction is close to the reaction temperature.

  13. Bursectomy at radical gastrectomy

    Institute of Scientific and Technical Information of China (English)

    Cuneyt; Kayaalp

    2015-01-01

    Radical gastrectomy with extended lymph node dissec tion and prophylactic resection of the omentum, peri toneum over the posterior lesser sac, pancreas and/o spleen was advocated at the beginning of the 1960 s in Japan. In time, prophylactic routine resections of the pancreas and/or spleen were abandoned because of the high incidence of postoperative complications. However omentectomy and bursectomy continued to be standard parts of traditional radical gastrectomy. The bursaomentalis was thought to be a natural barrier against invasion of cancer cells into the posterior part of the stomach. The theoretical rationale for bursectomy was to reduce the risk of peritoneal recurrences by eliminating the peritoneum over the lesser sac, which might include free cancer cells or micrometastases. Over time, the indication for bursectomy was gradually reduced to only patients with posterior gastric wall tumors penetrating the serosa. Despite its theoretical advantages, its benefit for recurrence or survival has not been proven yet. The possible reasons for this inconsistency are discussed in this review. In conclusion, the value of bursectomy in the treatment of gastric cancer is still under debate and large-scale randomized studies are necessary. Until clear evidence of patient benefit is obtained, its routine use cannot be recommended.

  14. Radically innovative steelmaking technologies

    Science.gov (United States)

    Szekely, Julian

    1980-09-01

    The steel industry is faced with serious problems caused by the increasing cost of energy, labor and capital and by tough overseas competition, employing new highly efficient process plants. The very high cost of capital and of capital equipment renders the construction of new green field site plants, exemplifying the best available technology economically unattractive. For this reason, over the long term the development radically innovative steelmaking technologies appears to be the only satisfactory resolution of this dilemma. The purpose of this article is to present a critical review of some of the radically innovative steelmaking technologies that have been proposed during the past few years and to develop the argument that these indeed do deserve serious consideration at the present time. It should be stressed, however, that these innovative technologies can be implemented only as part of a carefully conceived long range plan, which contains as a subset short term solutions, such as trigger prices improved investment credits, and so forth and intermediate term solutions, such as more extensive use of continuous casting, external desulfurization and selective modernization in general.

  15. Radicals in Berkeley?

    Science.gov (United States)

    Linn, Stuart

    2015-04-03

    In a previous autobiographical sketch for DNA Repair (Linn, S. (2012) Life in the serendipitous lane: excitement and gratification in studying DNA repair. DNA Repair 11, 595-605), I wrote about my involvement in research on mechanisms of DNA repair. In this Reflections, I look back at how I became interested in free radical chemistry and biology and outline some of our bizarre (at the time) observations. Of course, these studies could never have succeeded without the exceptional aid of my mentors: my teachers; the undergraduate and graduate students, postdoctoral fellows, and senior lab visitors in my laboratory; and my faculty and staff colleagues here at Berkeley. I am so indebted to each and every one of these individuals for their efforts to overcome my ignorance and set me on the straight and narrow path to success in research. I regret that I cannot mention and thank each of these mentors individually.

  16. Initial evaluation of {sup 227}Th-p-benzyl-DOTA-rituximab for low-dose rate {alpha}-particle radioimmunotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, Jostein [Department of Radiation Biology, Rikshospitalet-Radiumhospitalet HE, Montebello, 0310 Oslo (Norway)]. E-mail: jostein.dahle@labmed.uio.no; Borrebaek, Jorgen [Algeta ASA, Kjelsasveien 172 A, 0411 Oslo (Norway); Melhus, Katrine B. [Department of Radiation Biology, Rikshospitalet-Radiumhospitalet HE, Montebello, 0310 Oslo (Norway); Bruland, Oyvind S. [Department of Clinical Medicine, University of Oslo, 0316 Oslo (Norway); Department of Oncology, Rikshospitalet-Radiumhospitalet HE, Montebello, 0310 Oslo (Norway); Salberg, Gro [Algeta ASA, Kjelsasveien 172 A, 0411 Oslo (Norway); Olsen, Dag Rune [Department of Radiation Biology, Rikshospitalet-Radiumhospitalet HE, Montebello, 0310 Oslo (Norway); Larsen, Roy H. [Algeta ASA, Kjelsasveien 172 A, 0411 Oslo (Norway)

    2006-02-15

    Radioimmunotherapy has proven clinically effective in patients with non-Hodgkin's lymphoma. Radioimmunotherapy trials have so far been performed with {beta}-emitting isotopes. In contrast to {beta}-emitters, the shorter range and high linear energy transfer (LET) of {alpha} particles allow for more efficient and selective killing of individually targeted tumor cells. However, there are several obstacles to the use of {alpha}-particle immunotherapy, including problems with chelation chemistry and nontarget tissue toxicity. The {alpha}-emitting radioimmunoconjugate {sup 227}Th-DOTA-p-benzyl-rituximab is a new potential anti-lymphoma agent that might overcome some of these difficulties. The present study explores the immunoreactivity, in vivo stability and biodistribution, as well as the effect on in vitro cell growth, of this novel radioimmunoconjugate. To evaluate in vivo stability, uptake in balb/c mice of the {alpha}-particle-emitting nuclide {sup 227}Th alone, the chelated form, {sup 227}Th-p-nitrobenzyl-DOTA and the radioimmunoconjugate {sup 227}Th-DOTA-p-benzyl-rituximab was compared in a range of organs at increasing time points after injection. The immunoreactive fraction of {sup 227}Th-DOTA-p-benzyl-rituximab was 56-65%. During the 28 days after injection of radioimmunoconjugate only, very modest amounts of the {sup 227}Th had detached from DOTA-p-benzyl-rituximab, indicating a relevant stability in vivo. The half-life of {sup 227}Th-DOTA-p-benzyl-rituximab in blood was 7.4 days. Incubation of lymphoma cells with {sup 227}Th-DOTA-p-benzyl-rituximab resulted in a significant antigen-dependent inhibition of cell growth. The data presented here warrant further studies of {sup 227}Th-DOTA-p-benzyl-rituximab.

  17. Short and stereoselective total synthesis of furano lignans (+/-)-dihydrosesamin, (+/-)-lariciresinol dimethyl ether, (+/-)-acuminatin methyl ether, (+/-)-sanshodiol methyl ether, (+/-)-lariciresinol, (+/-)-acuminatin, and (+/-)-lariciresinol monomethyl ether and furofuran lignans (+/-)-sesamin, (+/-)-eudesmin, (+/-)-piperitol methyl ether, (+/-)-pinoresinol, (+/-)-piperitol, and (+/-)-pinoresinol monomethyl ether by radical cyclization of epoxides using a transition-metal radical source.

    Science.gov (United States)

    Roy, Subhas Chandra; Rana, Kalyan Kumar; Guin, Chandrani

    2002-05-17

    Intramolecular radical cyclization of suitably substituted epoxy ethers 4a-g using bis(cyclopentadienyl)titanium(III) chloride as the radical source resulted in trisubstituted tetrahydrofurano lignans and 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane lignans depending on the reaction conditions. The titanium(III) species was prepared in situ from commercially available titanocene dichloride and activated zinc dust in THF. Upon radical cyclization followed by acidic workup, epoxy olefinic ethers 4a-g afforded furano lignans dihydrosesamin 1a, lariciresinol dimethyl ether 1b, acuminatin methyl ether 1e, and sanshodiol methyl ether 1g directly and lariciresinol 1h, acuminatin 1i, and lariciresinol monomethyl ether 1j after removal of the benzyl protecting group by controlled hydrogenolysis of the corresponding cyclized products. The furofuran lignans sesamin 2a, eudesmin 2b, and piperitol methyl ether 2e were also prepared directly by using the same precursors 4a-f on radical cyclization followed by treatment with iodine and pinoresinol 2h, piperitol 2i, and pinoresinol monomethyl ether 2j after controlled hydrogenolysis of the benzyl protecting group of the corresponding cyclized products. Two naturally occurring acyclic lignans, secoisolariciresinol 5h and secoisolariciresinol dimethyl ether 5b, have also been prepared by exhaustive hydrogenolysis of 2h and 2b, respectively.

  18. Radical chic? Yes we are!

    OpenAIRE

    Hartle, J.F.

    2012-01-01

    Ever since Tom Wolfe in a classical 1970 essay coined the term "radical chic", upper-class flirtation with radical causes has been ridiculed. But by separating aesthetics from politics Wolfe was actually more reactionary than the people he criticized, writes Johan Frederik Hartle.

  19. Muoniated acyl and thioacyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, Iain [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Brodovitch, Jean-Claude [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Ghandi, Khashayar [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Percival, Paul W. [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada)]. E-mail: percival@sfu.ca

    2006-03-31

    The product of the reaction of muonium with tert-butylisocyanate was previously assigned as the muoniated tert-butylaminyl radical (I. McKenzie, J.-C. Brodovitch, K. Ghandi, S. Kecman, P. W. Percival, Physica B 326 (2003) 76). This assignment is incorrect since the muon and {sup 14}N hyperfine-coupling constants (hfcc) of this radical would have the opposite sign, which is in conflict with the experimental results. The radical is now reassigned as the muoniated N-tert-butylcarbamoyl radical, based on the similarities between the experimental muon and {sup 14}N hfcc and hfcc calculated at the UB3LYP/6-311G(d,p)//UB3LYP/EPR-III level. The large zero-point energy in the N-Mu bond results in the dissociation barrier of the muoniated N-tert-butylcarbamoyl radical being above the combined energy of the reactants, in contrast to the N-tert-butylcarbamoyl radical where the dissociation barrier lies below the combined energy of the reactants. The reaction of muonium with tert-butylisothiocyanate produced both conformers of the muoniated N-tert-butylthiocarbamoyl radical and their assignment was based on the similarities between the experimental and calculated muon hfcc. These are the first acyl and thioacyl radicals to be directly detected by muon spin spectroscopy.

  20. Melatonin scavenges phenylglyoxylic ketyl radicals.

    Science.gov (United States)

    Sersen, F; Vencel, T; Annus, J

    2004-12-01

    The antioxidant properties of melatonin were tested in this work by EPR technique. It was found that melatonin scavenges phenylglyoxylic ketyl radicals. Its effectiveness was 10-times lower than that of vitamin C. A new method of generation of phenylglyoxylic ketyl radicals by spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propan-2-ol was used.

  1. Core-Shell Structural CdS@SnO₂ Nanorods with Excellent Visible-Light Photocatalytic Activity for the Selective Oxidation of Benzyl Alcohol to Benzaldehyde.

    Science.gov (United States)

    Liu, Ya; Zhang, Ping; Tian, Baozhu; Zhang, Jinlong

    2015-07-01

    Core-shell structural CdS@SnO2 nanorods (NRs) were fabricated by synthesizing SnO2 nanoparticles with a solvent-assisted interfacial reaction and further anchoring them on the surface of CdS NRs under ultrasonic stirring. The morphology, composition, and microstructures of the obtained samples were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption. It was found that SnO2 nanoparticles can be tightly anchored on the surface of CdS NRs, and the thickness of SnO2 shells can be conveniently adjusted by simply changing the addition amount of SnO2 quantum dots. UV-vis diffuse reflectance spectrum indicated that SnO2 shell layer also can enhance the visible light absorption of CdS NRs to a certain extent. The results of transient photocurrents and photoluminescence spectra revealed that the core-shell structure can effectively promote the separation rate of electron-hole pairs and prolong the lifetime of electrons. Compared with the single CdS NRs, the core-shell structural CdS@SnO2 exhibited a remarkably enhanced photocatalytic activity for selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) under visible light irradiation, attributed to the more efficient separation of electrons and holes, improved surface area, and enhanced visible light absorption of core-shell structure. The radical scavenging experiments proved that in acetonitrile solution, ·O2- and holes are the main reactive species responsible for BA to BAD transformation, and the lack of ·OH radicals is favorable to obtaining high reaction selectivity.

  2. EPR and DFT Study of the Polycyclic Aromatic Radical Cations from FriedeI-Crafts Alkylation Reactions

    Institute of Scientific and Technical Information of China (English)

    Tao Wang; An-an Wu; Li-guo Gao; Han-qing Wang

    2009-01-01

    Electron paramagnetic resonance and electron-nuclear double resonance methods were used to study the polycyclic aromatic radical cations produced in a Friedel-Crafts alkylating sys-tem, with m-xylene, or p-xylene and alkyl chloride. The results indicate that the observed electron paramagnetic resonance spectra are due to polycyclic aromatic radicals formed from the parent hydrocarbons. It is suggested that benzyl halides produced in the Friedel-Crafts alkylation reactions undergo Scholl self-condensation to give polycyclic aromatic hydrocar-bons, which are converted into corresponding polycyclic aromatic radical cations in the presence of AlCl3. The identification of observed two radicals 2,6-dimethylanthracene and 1,4,5,8-tetramethylanthracene were supported by density functional theory calculations us-ing the B3LYP/6-31G(d,p)//B3LYP/6-31G(d) approach. The theoretical coupling constants support the experimental assignment of the observed radicals.

  3. The role of structural effects on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites. A time-resolved kinetic study.

    Science.gov (United States)

    Bietti, Massimo; Calcagni, Alessandra; Salamone, Michela

    2010-07-02

    A time-resolved kinetic study on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites ((RO)(3)P: R = Me, Et, i-Pr, t-Bu; (ArO)(3)P: Ar = C(6)H(5), 2,4-(t-Bu)(2)C(6)H(3)) has been carried out. In the (RO)(3)P series, the alkoxyl radicals (cumyloxyl (CumO(*)) and benzyloxyl (BnO(*))) undergo addition to the phosphorus center with formation of intermediate tetraalkoxyphosphoranyl radicals (R'OP(*)(OR)(3): R = Me, Et, i-Pr, t-Bu; R' = Bn, Cum). The addition rate constants are influenced by steric effects, decreasing on going from R = Me to R = t-Bu and from BnO(*) to CumO(*). Rate constants for beta-scission of the phosphoranyl radicals R'OP(*)(OR)(3) have also been determined, increasing, for a given alkyl group R, in the order R' = tert-butyl < R' = benzyl < R' = cumyl and, for a given R' group, on going from R = Me to R = i-Pr. This behavior has been explained in terms of the relative stability of the radicals formed after beta-scission, suggesting moreover that steric effects play in this case a minor role. CumO(*) reacts with triaryl phosphites (ArO)(3)P to give phenoxyl radicals, with rate constants that are influenced to a limited extent by substitution of the aromatic rings. The radical scavenging ability of these substrates is briefly discussed.

  4. Synthesis and antimicrobial activities of 1-(3-benzyl-4-oxo-3H-quinazolin-2-yl-4-(substitutedthiosemicarbazide derivatives

    Directory of Open Access Journals (Sweden)

    Alagarsamy Veerachamy

    2015-01-01

    Full Text Available A series of 1-(3-benzyl-4-oxo-3H-quinazolin-2-yl-4-(substituted thiosemicarbazides (AS1-AS10 were obtained by the reaction of 2-hydrazino- 3-benzyl quinazolin-4(3H-one (6 with different dithiocarbamic acid methyl ester derivatives. The key intermediate 3-benzyl-2-thioxo-2,3-dihydro-1Hquinazolin-4-one (4 was obtained by reacting benzyl amine (1 with carbon disulphide and sodium hydroxide in dimethyl sulphoxide to give sodium dithiocarbamate, which was methylated with dimethyl sulfate to yield the dithiocarbamic acid methyl ester (2 and condensed with methyl anthranilate (3 in ethanol yielded the desired compound (4 via the thiourea intermediate. The SH group of compound (4 was methylated for the favorable nucleophilic displacement reaction with hydrazine hydrate, which afford 2-hydrazino-3- benzyl-3H-quinazolin-4-one (6. The IR, 1H, and 13C NMR spectrum of these compounds showed the presence of peaks due to thiosemicarbazides, carbonyl (C=O, NH and aryl groups. The quinazolin-4-one moiety molecular ion peaks (m/z 144 were observed all the mass spectrum of compounds (AS1-AS10. Elemental (C, H, N analysis satisfactorily confirmed purity of the synthesized compounds and elemental composition. All synthesized compounds were also screened for their antimicrobial activity against selective gram positive and gram negative by agar dilution method. In the present study compounds AS8 and AS9 were emerged as the most active compounds of the series.

  5. Evolution of plant defense mechanisms. Relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases.

    Science.gov (United States)

    Gang, D R; Kasahara, H; Xia, Z Q; Vander Mijnsbrugge, K; Bauw, G; Boerjan, W; Van Montagu, M; Davin, L B; Lewis, N G

    1999-03-12

    Pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." This study establishes the first known catalytic function for the latter, as being able to engender the NADPH-dependent reduction of phenylcoumaran benzylic ethers. Accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. In this investigation, the phenylcoumaran benzylic ether reductase from the gymnosperm, Pinus taeda, was cloned, with the recombinant protein heterologously expressed in Escherichia coli. The purified enzyme reduces the benzylic ether functionalities of both dehydrodiconiferyl alcohol and dihydrodehydrodiconiferyl alcohol, with a higher affinity for the former, as measured by apparent Km and Vmax values and observed kinetic 3H-isotope effects. It abstracts the 4R-hydride of the required NADPH cofactor in a manner analogous to that of the pinoresinol-lariciresinol reductases and isoflavone reductases. A similar catalytic function was observed for the corresponding recombinant reductase whose gene was cloned from the angiosperm, Populus trichocarpa. Interestingly, both pinoresinol-lariciresinol reductases and isoflavone reductases catalyze enantiospecific conversions, whereas the phenylcoumaran benzylic ether reductase only shows regiospecific discrimination. A possible evolutionary relationship among the three reductase classes is proposed, based on the supposition that phenylcoumaran benzylic ether reductases represent the progenitors of pinoresinol-lariciresinol and isoflavone reductases.

  6. Free radicals and male reproduction.

    Science.gov (United States)

    Agarwal, Ashok; Allamaneni, Shyam S R

    2011-03-01

    Male factor accounts for almost 50% cases of infertility. The exact mechanism of sperm dysfunction is not known in many cases. Extensive research in the last decade has led to the identification of free radicals (reactive oxygen species) as mediators of sperm dysfunction in both specific diagnoses and idiopathic cases of male infertility. Elevated levels of reactive oxygen species are seen in up to 30-80% of men with male infertility. The role of free radicals has been studied extensively in the process of human reproduction. We know now that a certain level of free radicals is necessary for normal sperm function, whereas an excessive level of free radicals can cause detrimental effect on sperm function and subsequent fertilisation and offspring health. Oxidative stress develops when there is an imbalance between generation of free radicals and scavenging capacity of anti-oxidants in reproductive tract. Oxidative stress has been shown to affect both standard semen parameters and fertilising capacity. In addition, high levels of free radicals have been associated with lack of or poor fertility outcome after natural conception or assisted reproduction. Diagnostic techniques to quantify free radicals in infertile patients can assist physicians treating patients with infertility to plan for proper treatment strategies. In vivo anti-oxidants can be used against oxidative stress in male reproductive tract. Supplementation of in vitro anti-oxidants can help prevent the oxidative stress during sperm preparation techniques in assisted reproduction.

  7. Guest Editorial: Processes of Radicalization and De-Radicalization

    Directory of Open Access Journals (Sweden)

    Donatella Della Porta

    2012-05-01

    Full Text Available The study of radicalization and de-radicalization, understood as processes leading towards the increased or decreased use of political violence, is central to the question of how political violence emerges, how it can be prevented, and how it can be contained. The focus section of this issue of the International Journal of Conflict and Violence addresses radicalization and de-radicalization, seeking to develop a more comprehensive understanding of the processes, dynamics, and mechanisms involved and taking an interdisciplinary approach to overcome the fragmentation into separate disciplines and focus areas. Contributions by Pénélope Larzillière, Felix Heiduk, Bill Kissane, Hank Johnston, Christian Davenport and Cyanne Loyle, Veronique Dudouet, and Lasse Lindekilde address repressive settings, legitimacy, institutional aspects, organizational outcomes, and dynamics in Europe, Asia, Africa, and North and South America.

  8. Primary amino acid derivatives: substitution of the 4'-N'-benzylamide site in (R)-N'-benzyl 2-amino-3-methylbutanamide, (R)-N'-benzyl 2-amino-3,3-dimethylbutanamide, and (R)-N'-benzyl 2-amino-3-methoxypropionamide provides potent anticonvulsants with pain-attenuating properties.

    Science.gov (United States)

    King, Amber M; Salomé, Christophe; Salomé-Grosjean, Elise; De Ryck, Marc; Kaminski, Rafal; Valade, Anne; Stables, James P; Kohn, Harold

    2011-10-13

    Recently, we reported that select N'-benzyl 2-substituted 2-amino acetamides (primary amino acid derivatives (PAADs)) exhibited pronounced activities in established whole animal anticonvulsant (i.e., maximal electroshock seizure (MES)) and neuropathic pain (i.e., formalin) models. The anticonvulsant activities of C(2)-hydrocarbon N'-benzyl 2-amino acetamides (MES ED(50) = 13-21 mg/kg) exceeded those of phenobarbital (ED(50) = 22 mg/kg). Two additional studies defining the structure-activity relationship of PAADs are presented in this issue of the journal. In this study, we demonstrated that the anticonvulsant activities of (R)-N'-benzyl 2-amino-3-methylbutanamide and (R)-N'-benzyl 2-amino-3,3-dimethylbutanamide were sensitive to substituents at the 4'-N'-benzylamide site; electron-withdrawing groups retained activity, electron-donating groups led to a loss of activity, and incorporating either a 3-fluorobenzyloxy or 3-fluorophenoxymethyl group using a rationally designed multiple ligand approach improved activity. Additionally, we showed that substituents at the 4'-N'-benzylamide site of (R)-N'-benzyl 2-amino-3-methoxypropionamide also improved anticonvulsant activity, with the 3-fluorophenoxymethyl group providing the largest (∼4-fold) increase in activity (ED(50) = 8.9 mg/kg), a value that surpassed phenytoin (ED(50) = 9.5 mg/kg). Collectively, the pharmacological findings provided new information that C(2)-hydrocarbon PAADs represent a novel class of anticonvulsants.

  9. 5-Benzyl-5H-pyrido[3,2-b]indole

    Directory of Open Access Journals (Sweden)

    Julien Letessier

    2011-09-01

    Full Text Available The title compound, C18H14N2, was prepared by twofold Pd-catalyzed arylamination of a cyclic pyrido–benzo–iodolium salt. In the crystal, two molecules of 9-benzyl-δ-carboline form centrosymmetrical dimers with distances of 3.651 (2 Å between the centroids of the pyridine rings and 3.961 (2 Å between the centroids of the pyrrole and pyridine rings. The phenyl rings point to the other molecule in the dimer and the carboline core is essentially planar [maximum deviation of 0.027 (2 Å].

  10. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Benzyl Benzoate with Acetonitrile and Benzonitrile

    Directory of Open Access Journals (Sweden)

    N. Jaya Madhuri

    2011-01-01

    Full Text Available Ultrasonic velocity, density and viscosity have been measured in the binary mixtures of benzyl benzoate with acetonitrile, benzonitrile at three temperatures 30, 40 and 50 °C. From the experimental data, thermodynamic parameters like adiabatic compressibility, internal pressure, enthalpy, activation energy etc., were computed and the molecular interactions were predicted based on the variation of excess parameters in the mixture. Also theoretical evaluation of velocities was made employing the standard theories. CFT and NOMOTO were found to have an edge. All the three mixtures have shown out strong intermolecular interactions between the unlike molecules and endothermic type of chemical reaction.

  11. Ultrasonicated Synthesis of N-Benzyl-2,3-substituted Morpholines, via the Mitsunobu Diol Cyclisation

    Directory of Open Access Journals (Sweden)

    B. Jayachandra Reddy

    2010-01-01

    Full Text Available A facile five step synthesis of N-benzyl-2,3-substituted morpholines (i-iii was performed. The key steps were microwave assisted Friedel-crafts acylation and diol cyclization carried out via an ultra sonication of Mitsunobu reaction using DEAD (diethylazodicarboxylate, TPP in THF for 1 h. The morpholine products were generated as diasteriomers (ii andiii which has been separated by the column chromatography to good yield. The structure of compounds (i-iii has been characterized by the spectral and chemical studies.

  12. Development of Highly Effective Nanoparticle Spinel Catalysts for Aerobic Oxidation of Benzylic Alcohols

    Institute of Scientific and Technical Information of China (English)

    JI,Hong-Bing(纪红兵); WANG,Le-Fu(王乐夫)

    2002-01-01

    Spinel catalyst MnFe1.8Cu0.15Ru0.05O4 with particle size of about 42 nm is an effective heterogeneous catalyst for the oxidation of benzylic alcohols. The substitution of Fe for Cu improves its catalytic activity. Based on the characterization of BET, XPS and EXAFS, two factors influencing the structure and texture of the catalyst caused by the substitution of Cu for Fe may be assumed: physical factor responsible for the increasing of surface area; chemical factor responsible for the transformation of Ru-O bonds to Ru = O bonds. β-Elimination is considered to be an important step in the reaction.

  13. Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions.

    Science.gov (United States)

    Kelly, Paul P; Eichler, Anja; Herter, Susanne; Kranz, David C; Turner, Nicholas J; Flitsch, Sabine L

    2015-01-01

    Cytochrome P450 monooxygenases are useful biocatalysts for C-H activation, and there is a need to expand the range of these enzymes beyond what is naturally available. A panel of 93 variants of active self-sufficient P450cam[Tyr96Phe]-RhFRed fusion enzymes with a broad diversity in active site amino acids was developed by screening a large mutant library of 16,500 clones using a simple, highly sensitive colony-based colorimetric screen against indole. These mutants showed distinct fingerprints of activity not only when screened in oxidations of substituted indoles but also for unrelated oxidations such as benzylic hydroxylations.

  14. Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

    Directory of Open Access Journals (Sweden)

    Paul P. Kelly

    2015-09-01

    Full Text Available Cytochrome P450 monooxygenases are useful biocatalysts for C–H activation, and there is a need to expand the range of these enzymes beyond what is naturally available. A panel of 93 variants of active self-sufficient P450cam[Tyr96Phe]-RhFRed fusion enzymes with a broad diversity in active site amino acids was developed by screening a large mutant library of 16,500 clones using a simple, highly sensitive colony-based colorimetric screen against indole. These mutants showed distinct fingerprints of activity not only when screened in oxidations of substituted indoles but also for unrelated oxidations such as benzylic hydroxylations.

  15. 3-Benzyl-8-methoxy-2-sulfanylidene-1,2,3,4-tetrahydroquinazolin-4-one

    Directory of Open Access Journals (Sweden)

    Rashad Al-Salahi

    2012-06-01

    Full Text Available The tetrahydroquinazole fused-ring system of the title compound, C16H14N2O2S, is roughly planar (r.m.s. deviation = 0.039 Å; the phenyl ring of the benzyl substituent is aligned at 78.1 (1° with respect to the mean plane of the fused-ring system. In the crystal, two molecules are linked by a pair of N—H...S hydrogen bonds about a center of inversion, generating a dimer.

  16. N-Benzyl-2,5-bis(2-thienyl)pyrrole.

    Science.gov (United States)

    Palenzuela Conde, Jesús; Elsegood, Mark R J; Ryder, Karl S

    2004-03-01

    The solid-state structure of the title compound, C19H15NS2, is unusual among substituted thiophene/pyrrole derivatives in that the molecular packing is dominated by pi-pi interactions between the benzyl substituents. This may be due to the large torsion angles observed between adjacent heterocycles. Torsion angles between adjacent rings in polypyrrole and polythiophene conducting polymers are related to conjugation length and the conductivity properties of the polymer materials. The title compound crystallizes in space group P21/c with two molecules in the asymmetric unit, both of which exhibit disorder in one of their thiophene rings.

  17. Gold( i )-catalysed dehydrative formation of ethers from benzylic alcohols and phenols

    KAUST Repository

    Veenboer, Richard M. P.

    2015-01-01

    © The Royal Society of Chemistry 2015. We report the cross-dehydrative reaction of two alcohols to form unsymmetrical ethers using NHC-gold(i) complexes (NHC = N-heterocyclic carbene). Our progress in developing this reaction into a straightforward procedure is discussed in detail. The optimised methodology proceeds under mild reaction conditions and produces water as the sole by-product. The synthetic utility of this environmentally benign methodology is exemplified by the formation of a range of new ethers from readily available phenols bearing electron withdrawing substituents and secondary benzylic alcohols with various substituents. Finally, we present experimental results to account for the chemoselectivity obtained in these reactions.

  18. A sustainable and efficient synthesis of benzyl phosphonates using PEG/KI catalytic system

    Science.gov (United States)

    Gawande, Manoj; Disale, Shamrao; Kale, Sandip; Abraham, George; Kahandal, Sandeep; Sawarkar, Ashish

    2016-08-01

    An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI) could be used for other related organic transformations.

  19. A sustainable and efficient synthesis of benzyl phosphonates using PEG/KI catalytic system

    Directory of Open Access Journals (Sweden)

    Manoj B. Gawande

    2016-08-01

    Full Text Available An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI could be used for other related organic transformations.

  20. Role of allyl group in the hydroxyl and peroxyl radical scavenging activity of S-allylcysteine.

    Science.gov (United States)

    Maldonado, Perla D; Alvarez-Idaboy, J Raúl; Aguilar-González, Adriana; Lira-Rocha, Alfonso; Jung-Cook, Helgi; Medina-Campos, Omar Noel; Pedraza-Chaverrí, José; Galano, Annia

    2011-11-17

    S-Allylcysteine (SAC) is the most abundant compound in aged garlic extracts, and its antioxidant properties have been demonstrated. It is known that SAC is able to scavenge different reactive species including hydroxyl radical (•OH), although its potential ability to scavenge peroxyl radical (ROO•) has not been explored. In this work the ability of SAC to scavenge ROO• was evaluated, as well as the role of the allyl group (-S-CH(2)-CH═CH(2)) in its free radical scavenging activity. Two derived compounds of SAC were prepared: S-benzylcysteine (SBC) and S-propylcysteine (SPC). Their abilities to scavenge •OH and ROO• were measured. A computational analysis was performed to elucidate the mechanism by which these compounds scavenge •OH and ROO•. SAC was able to scavenge •OH and ROO•, in a concentration-dependent way. Such activity was significantly ameliorated when the allyl group was replaced by benzyl or propyl groups. It was shown for the first time that SAC is able to scavenge ROO•.

  1. Synthesis of Nickel Hexacyanoferrate Nanoparticles and Their Potential as Heterogeneous Catalysts for the Solvent-Free Oxidation of Benzyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    Shah R. ALI; Prakash CHANDRA; Mamta LATWAL; Shalabh K. JAIN; Vipin K. BANSAL; Sudhanshu P. SINGH

    2011-01-01

    Nickel hexacyanoferrate nanoparticles were synthesized and characterized using elemental analysis,thermal analysis,infrared spectroscopy,and X-ray diffraction.A FE-SEM image of the nickel hexacyanoferrate showed that it consists of nearly spherical particles with sizes ranging from 30 to 70 nm.The synthesized material was found to be a heterogeneous catalyst useful for the solvent-free oxidation of benzyl alcohol with H2O2 as an oxidant.A 36% conversion of benzyl alcohol to benzaldehyde was achieved under optimized reaction conditions using specific parameters such as the amount of catalyst,the temperature,the benzyl alcohol to H2O2 molar ratio,and the reaction time.

  2. Pseudo-Four Component Synthesis of Mono- and Di-Benzylated-1,2,3-Triazoles Derived from Aniline

    Directory of Open Access Journals (Sweden)

    Daniel Mendoza-Espinosa

    2013-12-01

    Full Text Available The pseudo-four component click synthesis of dibenzylated 1,2,3-triazoles derived from aniline is reported. The cycloaddition of sodium azide to N-(prop-2-ynyl-benzenamine (I in the presence of equimolar amounts of p-substituted benzyl derivatives, yields a mixture of mono- and dibenzylated 1,2,3-triazoles. When two equivalents of the benzyl derivative are added to the multicomponent reaction, the selective preparation of the dibenzylated compounds is achieved. The reactivity of the aniline N-H bond in monobenzylated 1,2,3-triazoles was tested by treatment with one equivalent of a p-substituted benzyl chloride at 40 °C, rendering the dibenzylated derivatives quantitatively.

  3. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2014-07-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  4. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2013-01-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  5. Penile rehabilitation after radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Ohl, Dana A; Ralph, David;

    2013-01-01

    The pathophysiology of erectile dysfunction after radical prostatectomy (RP) is believed to include neuropraxia, which leads to temporarily reduced oxygenation and subsequent structural changes in penile tissue. This results in veno-occlusive dysfunction, therefore, penile rehabilitation programm...

  6. Redox Properties of Free Radicals.

    Science.gov (United States)

    Neta, P.

    1981-01-01

    Describes pulse radiolysis as a useful means in studing one-electron redox potentials. This method allows the production of radicals and the determination of their concentration and rates of reaction. (CS)

  7. Kinetic Study of the Reaction of the Phthalimide-N-oxyl Radical with Amides: Structural and Medium Effects on the Hydrogen Atom Transfer Reactivity and Selectivity.

    Science.gov (United States)

    Bietti, Massimo; Forcina, Veronica; Lanzalunga, Osvaldo; Lapi, Andrea; Martin, Teo; Mazzonna, Marco; Salamone, Michela

    2016-12-02

    A kinetic study of the hydrogen atom transfer (HAT) reactions from a series of secondary N-(4-X-benzyl)acetamides and tertiary amides to the phthalimide-N-oxyl radical (PINO) has been carried out. The results indicate that HAT is strongly influenced by structural and medium effects; in particular, the addition of Brønsted and Lewis acids determines a significant deactivation of C-H bonds α to the amide nitrogen of these substrates. Thus, by changing the reaction medium, it is possible to carefully control the regioselectivity of the aerobic oxidation of amides catalyzed by N-hydroxyphthalimide, widening the synthetic versatility of this process.

  8. 对羟基苯甲酸苄酯的合成%Synthesis of Benzyl p-hydroxybenzoate

    Institute of Scientific and Technical Information of China (English)

    王明星; 宋溪明; 张淑芬; 杨锦宗; 吕挺乔

    2001-01-01

    Benzyl p-hydroxybenzoate was prepared from benzyl chloride and p-hydroxybenzoic acid byphase transfer catalysis, in which xylene was used as an organic solvent, Na2CO3 aqueous solution asa condensing agent and Bu4NC1 as a phase transfer catalyst. The effects of reaction time, Na2CO3 con-centration and feed amount of raw materials were investigated. The concentration of Na2CO3 aqueoussolution was the most important factor. Prodact with purity greater 98% and yield more 85% was ob-tained.

  9. Efficient desymmetrization of 4,6-di-O-benzyl-myo-inositol by Lipozyme TL-IM.

    Science.gov (United States)

    Vasconcelos, Marcela G; Briggs, Raissa H C; Aguiar, Lucia C S; Freire, Denise M G; Simas, Alessandro B C

    2014-03-11

    The enantioselective enzymatic desymmetrization of 4,6-di-O-benzyl-myo-inositol, a myo-inositol derivative, was effectively catalyzed by Thermomyces lanuginosus lipase (TL-IM). The product 1D-1-O-acetyl-4,6-di-O-benzyl-myo-inositol, a useful precursor to inositol phosphates, was obtained in excellent yield and enantiomeric excess. Through the investigation of the effects of solvent, biocatalyst load, and temperature, a more economical procedure resulted. The feasibility of biocatalyst reuse was also shown.

  10. Biocatalytic resolution of benzyl glycidyl ether and its derivates by Talaromyces flavus: effect of phenyl ring substituents on enantioselectivity.

    Science.gov (United States)

    Wei, Chun; Chen, Yunyun; Shen, Honglei; Wang, Shan; Chen, Lin; Zhu, Qing

    2012-08-01

    Talaromyces flavus containing a constitutive epoxide hydrolase (EH) resolved racemic benzyl glycidyl ether and nine derivatives into their (R)-enantiomers. After optimization of the fermentation conditions, the specific EH activity and biomass concentration were improved from 13.5 U/g DCW and 14.8 g DCW/l to 26.2 U/g DCW and 31.3 g DCW/l, respectively, with final values for e.e. ( s ) of 96 % and E of 13 with (R)-benzyl glycidyl ether. Substituents on the phenyl ring, however, gave low enantioselectivities.

  11. Influence of Fluorination on the Conformational Properties and Hydrogen-Bond Acidity of Benzyl Alcohol Derivatives

    Science.gov (United States)

    Bogdan, Elena; Compain, Guillaume; Mtashobya, Lewis; Le Questel, Jean-Yves; Besseau, François; Galland, Nicolas; Linclau, Bruno; Graton, Jérôme

    2015-01-01

    The effect of fluorination on the conformational and hydrogen-bond (HB)-donating properties of a series of benzyl alcohols has been investigated experimentally by IR spectroscopy and theoretically with quantum chemical methods (ab initio (MP2) and DFT (MPWB1K)). It was found that o-fluorination generally resulted in an increase in the HB acidity of the hydroxyl group, whereas a decrease was observed upon o,o′-difluorination. Computational analysis showed that the conformational landscapes of the title compounds are strongly influenced by the presence of o-fluorine atoms. Intramolecular interaction descriptors based on AIM, NCI and NBO analyses reveal that, in addition to an intramolecular OH⋅⋅⋅F interaction, secondary CH⋅⋅⋅F and/or CH⋅⋅⋅O interactions also occur, contributing to the stabilisation of the various conformations, and influencing the overall HB properties of the alcohol group. The benzyl alcohol HB-donating capacity trends are properly described by an electrostatic potential based descriptor calculated at the MPWB1K/6-31+G(d,p) level of theory, provided solvation effects are taken into account for these flexible HB donors. PMID:26130594

  12. Highly Dispersed Gold Nanoparticles Supported on SBA-15 for Vapor Phase Aerobic Oxidation of Benzyl Alcohol.

    Science.gov (United States)

    Kumar, Ashish; Sreedhar, Bojja; Chary, Komandur V R

    2015-02-01

    Gold nanoparticles supported on SBA-15 are prepared by homogenous deposition-precipitation method (HDP) using urea as the precipitating agent. The structural features of the synthesized catalysts were characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption (BET), pore size distribution (PSD), CO chemisorption and X-ray photoelectron spectroscopy (XPS). The catalytic activity and stability of the Au/SBA-15 catalysts are investigated during the vapor phase aerobic oxidation of benzyl alcohol. The BJH pore size distribution results of SBA-15 support and Au/SBA-15 catalysts reveals that the formation of mesoporous structure in all the samples. TEM results suggest that Au nanoparticles are highly dispersed over SBA-15 and long range order of hexagonal mesopores of SBA-15 is well retained even after the deposition of Au metallic nanoparticles. XPS study reveals the formation of Au (0) after chemical reduction by NaBH4. The particle size measured from CO-chemisorption and TEM analysis are well correlated with the TOF values of the reaction. Au/SBA-1 5 catalysts are found to show higher activity compare to Au/TiO2 and Au/MgO catalysts during the vapor phase oxidation of benzyl alcohol. The catalytic functionality are well substantiated with particle size measured from TEM. The crystallite size of Au in both fresh and spent catalysts were measured from X-ray diffraction.

  13. The Role of Vanadia for the Selective Oxidation of Benzyl Alcohol over Heteropolymolybdate Supported on Alumina

    Institute of Scientific and Technical Information of China (English)

    Pasupulet Siva Nageswara RAO; Kasanneni Tirumala Venkateswara RAO; Potharaju S. SAI PRASAD; Nakka LINGAIAH

    2011-01-01

    A series of 12-molybdophosphoric acid (MPA) supported on V2O5 dispersed γ-Al2O3 catalysts with different vanadia loadings were prepared by impregnation and characterized by N2 adsorption-desorption,X-ray diffraction,temperature-programmed reduction,in situ laser Raman spectroscopy,UV-Vis diffused reflectance spectroscopy,scanning electron microscopy,and temperature-programmed desorption of NH3 techniques.Their catalytic activities were evaluated for the vapor phase aerobic oxidation of benzyl alcohol.The catalysts exhibited high catalytic activity and the conversion of benzyl alcohol depended on the vanadia content while the catalyst with 15 wt% V2O5 content showed optimum activity.The characterization results suggest the presence of well-dispersed V2O5 and partially disintegrated Keggin ions of MPA on the support.In situ Raman studies showed a reduced Mo(IV) species when the catalysts were calcined at high temperatures.The high oxidation activity of the catalysts is related to the synergistic effect between MPA and V2O5.

  14. Modeling, Simulation, and Kinetic Studies of Solvent-Free Biosynthesis of Benzyl Acetate

    Directory of Open Access Journals (Sweden)

    Vijay Kumar Garlapati

    2013-01-01

    Full Text Available Solvent-free biosynthesis of benzyl acetate through immobilized lipase-mediated transesterification has been modeled and optimized through statistical integrated artificial intelligence approach. A nonlinear response surface model has been successfully developed based on central composite design with transesterification variables, namely, molarity of alcohol, reaction time, temperature, and immobilized lipase amount as input variables and molar conversion (% as an output variable. Statistical integrated genetic algorithm optimization approach results in an optimized molar conversion of 96.32% with the predicted transesterification variables of 0.47 M alcohol molarity in a reaction time of 13.1 h, at 37.5°C using 13.31 U of immobilized lipase. Immobilized lipase withstands more than 98% relative activity up to 6 recycles and maintains 50% relative activity until 12 recycles. The kinetic constants of benzyl acetate, namely, Km and Vmax were found to be 310 mM and 0.10 mmol h−1 g−1, respectively.

  15. Selective liquid phase oxidation of benzyl alcohol catalyzed by copper aluminate nanostructures

    Science.gov (United States)

    Ragupathi, C.; Judith Vijaya, J.; Thinesh Kumar, R.; John Kennedy, L.

    2015-01-01

    In this paper, a simple and economic route for the preparation of CuAl2O4 is proposed. The method was developed with the objective of obtaining a material with greater surface area, when compared to the spinel prepared by conventional combustion method (CCM). The catalytic properties of CuAl2O4 spinel prepared by CCM are compared with the one prepared microwave combustion method (MCM). Nano-sized CuAl2O4 were synthesized by both CCM and MCM using Opuntia dillenii haw as the plant extract, and were characterized by X-ray diffraction analysis (XRD), high resolution scanning electron microscopy (HR-SEM), N2 adsorption/desorption isotherms, and diffuse reflectance spectroscopy (DRS). Oxidation to their corresponding carbonyl compounds, high selectivity, and inexpensive precursors make this catalytic system a useful oxidation method for benzyl alcohol. The XRD results confirmed the formation of a cubic CuAl2O4. The formation of CuAl2O4 nanorices and nanorods structures were confirmed by HR-SEM. Through MCM method, CuAl2O4 (sample B) with a high specific surface area of was obtained. The band gap values of the (2.30 and 2.35 eV) for the obtained oxides are due to the nanometric dimensions of the nanostructures. The effect of the solvent, temperature, and oxidant on the oxidation of benzyl alcohol is reported.

  16. Dethreading of Tetraalkylsuccinamide-Based [2]Rotaxanes for Preparing Benzylic Amide Macrocycles.

    Science.gov (United States)

    Martinez-Cuezva, Alberto; Rodrigues, Leticia V; Navarro, Cristian; Carro-Guillen, Fernando; Buriol, Lilian; Frizzo, Clarissa P; Martins, Marcos A P; Alajarin, Mateo; Berna, Jose

    2015-10-16

    The dethreading of a series of succinamide-based [2]rotaxanes bearing benzylic amide macrocycles is reported herein. These transformations proceeded quantitatively either under flash vacuum pyrolysis, conventional heating, or microwave irradiation. Studying the size complementarity of the stoppers at the ends of the thread and the cavity of the macrocycle allowed us to set up the best substituents for implementing the extrusion of the thread from the interlocked precursors. A variety of (1)H NMR kinetic experiments were carried out in order to evaluate the rate constants of the dethreading process, the half-life times of the rotaxanes, and the influence of temperature and solvents on these processes. The use of dibutylamino groups as stoppers yielded the rotaxane precursor in a reasonable yield and allowed the quantitative deslipping of the rotaxane. The overall process, including the rotaxane formation and its further dethreading, has been exploited for preparing benzylic amide macrocycles enhancing, in most cases, the results of the classical (2 + 2) condensation and other reported stepwise syntheses. The kinetics of the dethreading process is fairly sensitive to the electronic effects of the substituents on the isophthalamide unit or to the electronic nature of the pyridine rings through a conformational equilibrium expanding or contracting the cavity of the interlocked precursor.

  17. Purification and characterization of benzyl alcohol- and benzaldehyde- dehydrogenase from Pseudomonas putida CSV86.

    Science.gov (United States)

    Shrivastava, Rahul; Basu, Aditya; Phale, Prashant S

    2011-08-01

    Pseudomonas putida CSV86 utilizes benzyl alcohol via catechol and methylnaphthalenes through detoxification pathway via hydroxymethylnaphthalenes and naphthaldehydes. Based on metabolic studies, benzyl alcohol dehydrogenase (BADH) and benzaldehyde dehydrogenase (BZDH) were hypothesized to be involved in the detoxification pathway. BADH and BZDH were purified to apparent homogeneity and were (1) homodimers with subunit molecular mass of 38 and 57 kDa, respectively, (2) NAD(+) dependent, (3) broad substrate specific accepting mono- and di-aromatic alcohols and aldehydes but not aliphatic compounds, and (4) BADH contained iron and magnesium, while BZDH contained magnesium. BADH in the forward reaction converted alcohol to aldehyde and required NAD(+), while in the reverse reaction it reduced aldehyde to alcohol in NADH-dependent manner. BZDH showed low K (m) value for benzaldehyde as compared to BADH reverse reaction. Chemical cross-linking studies revealed that BADH and BZDH do not form multi-enzyme complex. Thus, the conversion of aromatic alcohol to acid is due to low K (m) and high catalytic efficiency of BZDH. Phylogenetic analysis revealed that BADH is a novel enzyme and diverged during the evolution to gain the ability to utilize mono- and di-aromatic compounds. The wide substrate specificity of these enzymes enables strain to detoxify methylnaphthalenes to naphthoic acids efficiently.

  18. Theoretical and experimental studies of CIDNP kinetics in recombination of radical pairs by the method of switched external magnetic field. III. Free radicals in homogeneous solution

    Science.gov (United States)

    Fedin, M. V.; Bagryanskaya, E. G.; Purtov, P. A.; Makarov, T. N.; Paul, H.

    2002-10-01

    The method of chemically induced dynamic nuclear polarization in a switched external magnetic field (SEMF CIDNP) is applied here for the first time to an experimental study of short-lived neutral radicals in homogeneous solutions. With three photochemical reactions it is exemplified, that SEMF CIDNP allows investigations of the kinetics of the transient species with high time-resolution as well as a determination of their spin relaxation times in low magnetic fields. A theoretical approach is developed, which permits simulation and analysis of the experimental data. In weak magnetic fields (0.5-2.0 mT) the effective spin-lattice relaxation times for the decay of the chemically induced spin polarizations in benzyl, tert-butyl, and 2-hydroxy-2-propyl radicals are found to be T1=(3.8±0.5) μs, T1=(7.8±0.5) μs, and T1=(2.5±0.5) μs, respectively, in benzene solution at room temperature. They are in fair agreement with relaxation times determined by time-resolved X-band electron paramagnetic resonance spectroscopy at strong magnetic fields (≈350 mT).

  19. Peroxy radical partitioning during the AMMA radical intercomparison exercise

    Directory of Open Access Journals (Sweden)

    M. D. Andrés-Hernández

    2010-04-01

    Full Text Available Peroxy radicals were measured onboard two scientific aircrafts during the AMMA (African Monsoon Multidisciplinary Analysis campaign in summer 2006. This paper reports results from the flight on 16 August 2006 during which measurements of HO2 by laser induced fluorescence spectroscopy at low pressure (LIF-FAGE and total peroxy radicals (RO2*=HO2+ΣRO2, R= organic chain by two similar instruments based on the peroxy radical chemical amplification (PerCA technique were subject of a blind intercomparison. The German DLR-Falcon and the British FAAM-BAe-146 flew wing tip to wing tip for about 30 min making concurrent measurements on 2 horizontal level runs at 697 and 485 hPa over the same geographical area in Burkina Faso. A full set of supporting measurements comprising photolysis frequencies, and relevant trace gases like CO, NO, NO2, NOy, O3 and a wider range of VOCs were collected simultaneously.

    Results are discussed on the basis of the characteristics and limitations of the different instruments used. Generally, no data bias are identified and the RO2* data available agree quite reasonably within the instrumental errors. The [RO2*]/[HO2] ratios, which vary between 1:1 and 3:1, as well as the peroxy radical variability, concur with variations in photolysis rates and in other potential radical precursors. Model results provide additional information about dominant radical formation and loss processes.

  20. Density Functional Study of the High-Temperature Oxidation of o-, m- and p-Xylyl Radicals

    Science.gov (United States)

    Murakami, Yoshinori; Oguchi, Tatsuo; Hashimoto, Kohtaro; Nosaka, Yoshio

    2009-09-01

    Theoretical calculations at the CBS-QB3 level of theory have been performed to investigate the potential energy surface for the reaction of o-, m- and p-xylyl with molecular oxygen. The differences of the relative potential energies for the products and the transition states of o-, m- and p-xylyl with molecular oxygen were found to be within 8.5 kJ/mol at the CBS-QB3 level of theory. Although the reaction of m- and p-xylyl radicals with molecular oxygen have the same reaction pathways and also the same reaction thermochemistry as that of benzyl radicals, the o-xylylperoxy radicals formed by the reaction of o-xylyl + O2 had an additional intramolecular isomerization pathway to form the o-xylyl hydroperoxy radicals. The rate constants and the product branching ratios for the o-xylyl + O2 and its subsequent reactions were evaluated by the RRKM and master equation analysis. Possible roles for these reaction pathways on the combustion of o-xylenes are discussed.

  1. Standard Electrode Potentials Involving Radicals in Aqueous Solution: Inorganic Radicals

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, David A.; Huie, Robert E.; Koppenol, Willem H.; Lymar, Sergei V.; Merenyi, Gabor; Neta, Pedatsur; Ruscic, Branko; Stanbury, David M.; Steenken, Steen; Wardman, Peter

    2015-12-01

    Recommendations are made for standard potentials involving select inorganic radicals in aqueous solution at 25 °C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. The recommended data are summarized in tables of standard potentials, Gibbs energies of formation, radical pKa’s, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations

  2. Radical formation by heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Beuter, W.

    1982-09-01

    Certain reduced heavy metal ions can convert oxygen to a ''reactive oxygen species'' by donation of an electron. The reactive oxygen then attacks structures susceptible to oxidation, in particular unsaturated fatty acids, and peroxidizes them in a radical reaction. This process is inhibited by the presence of vitamin E and by other means. Peroxidized lipids decay forming free radicals in the process which themselves can peroxidise neighbouring lipids in a radical chain reaction. This decay is, moreover, catalysed by reduced heavy metal ions but on the other hand retarded by selenium-containing glutathione peroxidase. Radical formation by heavy metals is considerably involved in (i) the production of parenteral iron poisoning of the piglet (ii) haemolytic crisis occurring in ruminants through chronic copper poisoning (iii) the production of lead poisoning in ruminants and other animals. These types of poisonings are made worse by a deficiency of vitamin E and/or selenium. Factors which increase the bio-availability of the free heavy metal ion or reduce the redox potential thereof can aid radical formation as well as factors which lead to a reduction of the heavy metal ion e.g. cysteine, ascorbic acid or glucose.

  3. Synthesis of some novel fluoro isoxazolidine and isoxazoline derivatives using -benzyl fluoro nitrone via cycloaddition reaction in ionic liquid

    Indian Academy of Sciences (India)

    Bhaskar Chakraborty; Govinda Prasad Luitel

    2013-09-01

    1-Butyl-3-methylimidazolium-based ionic liquids are found to accelerate significantly the intermolecular 1,3-dipolar cycloaddition of -benzyl-fluoro nitrone derived in situ from 2,6-difluoro benzaldehyde and -benzylhydroxylamine, with activated alkenes and electron deficient alkynes to afford enhanced rates and improved yields of novel isoxazolidines and isoxazolines.

  4. Ivermectin alone or in combination with benzyl benzoate in the treatment of human immunodeficiency virus-associated scabies.

    Science.gov (United States)

    Alberici, F; Pagani, L; Ratti, G; Viale, P

    2000-05-01

    In order to establish a safe and reliable treatment for human immunodeficiency virus (HIV)-associated scabies, we have treated 60 episodes of scabies in this setting, occurring in 39 patients, with one of the following regimens: (i) topical treatment with benzyl benzoate solution; (ii) single-dose oral treatment with ivermectin alone; and (iii) combination therapy with benzyl benzoate solution and oral ivermectin, employing the same regimens as single-agent therapy. Patients were stratified according to the severity score of the disease and the outcome (eradication, relapse, failure). We found that both benzyl benzoate and ivermectin alone were quite effective in mild to moderate scabies, but they were both associated with an unacceptable rate of relapse and failure in severe or crusted scabies. In contrast, combined treatment produced an optimal rate of success, without significant treatment-related side-effects. Therefore, we consider that combination treatment with benzyl benzoate solution and oral ivermectin is preferable to single-agent therapy in crusted scabies occurring in HIV/acquired immune deficiency syndrome patients.

  5. Preparation of Novel meta- and para-Substituted N-Benzyl Protected Quinuclidine Esters and Their Resolution with Butyrylcholinesterase

    Directory of Open Access Journals (Sweden)

    Srđanka Tomić

    2012-01-01

    Full Text Available Since the optically active quinuclidin-3-ol is an important intermediate in the preparation of physiologically or pharmacologically active compounds, a new biocatalytic method for the production of chiral quinuclidin-3-ols was examined. Butyrylcholinesterase (BChE; EC 3.1.1.8 was chosen as a biocatalyst in a preparative kinetic resolution of enantiomers. A series of racemic, (R- and (S-esters of quinuclidin-3-ol and acetic, benzoic, phthalic and isonicotinic acids were synthesized, as well as their racemic quaternary N-benzyl, meta- and para-N-bromo and N-methylbenzyl derivatives. After the resolution, all N-benzyl protected groups were successfully removed by catalytic transfer hydrogenation with ammonium formate (10% Pd-C. Hydrolyses studies with BChE confirmed that (R-enantiomers of the prepared esters are much better substrates for the enzyme than (S-enantiomers. Introduction of bromine atom or methyl group in the meta or para position of the benzyl moiety resulted in a considerable improvement of the stereoselectivity compared to the non-substituted compounds. Optically pure quinuclidin-3-ols were prepared in high yields and enantiopurity by the usage of various N-benzyl protected groups and BChE as a biocatalyst.

  6. Study of the Chemical Mechanism Involved in the Formation of Tungstite in Benzyl Alcohol by the Advanced QEXAFS Technique

    DEFF Research Database (Denmark)

    Olliges‐Stadler, Inga; Stötzel, Jan; Koziej, Dorota

    2012-01-01

    Insight into the complex chemical mechanism for the formation of tungstite nanoparticles obtained by the reaction of tungsten hexachloride with benzyl alcohol is presented herein. The organic and inorganic species involved in the formation of the nanoparticles were studied by time‐dependent gas c...

  7. Disposition kinetics and bioavailability of the glucosidase inhibitor N-benzyl-1-deoxynojirimycin after various routes of administration in mice

    NARCIS (Netherlands)

    Faber, ED; Delbressine, LPC; vandeVorstenbosch, CG; vandenBroek, LAGM; Meijer, DKF; Stok, B.P.

    1997-01-01

    Pharmacokinetics, biodistribution, and excretion of the alpha-glucosidase inhibitor and antiviral compound N-benzyl-1-deoxynojirimycin (BndNM) were studied in mice, after intravenous, subcutaneous, and oral administration of a single radiolabeled dose, No metabolites were detected in plasma, urine,

  8. Nuclear magnetic resonance of D(-)-{alpha}-amino-benzyl penicillin; Ressonancia magnetica nuclear da D(-)-{alpha}-amino-benzil penicilina

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Monica R.M.P.; Gemal, Andre L.; San Gil, Rosane A.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1995-12-31

    The development of new drugs from penicillins has induced the study of this substances by nuclear magnetic resonance. Several samples of D(-)-{alpha}-amino-benzyl penicillin were analysed using {sup 13} C NMR techniques in aqueous solution and solid state. Spectral data of this compounds were shown and the results were presented and analysed 7 figs., 4 tabs.

  9. New chiral N, S-ligands with Thiophenyl at Benzylic Position. Palladium(Ⅱ)-catalyzed Enantioselective Allylic Alkylation

    Institute of Scientific and Technical Information of China (English)

    WU,Hao(吴昊); WU,Xun-Wei(巫循伟); HOU,Xue-Long(侯雪龙); DAI,Li-Xin(戴立信); WANG,Quan-Rui(王全瑞)

    2002-01-01

    New chiral N, S-ligands with oxazoline and thiphenyl substituents at benzene ring and benzylic position have been prepared and applied in palladium-catalyzed asymmetric allylic alkylation reaction to provide the product with high yield and entantioselectivity (82%-93% ee).

  10. Ir/Sn dual-reagent catalysis towards highly selective alkylation of arenes and heteroarenes with benzyl alcohols

    Indian Academy of Sciences (India)

    Sujit Roy; Susmita Podder; Joyanta Choudhury

    2008-09-01

    A catalytic combination of [Ir(COD)Cl]2-SnCl4 efficiently promotes the reactions of arenes and heteroarenes with 1°/2°/3° benzyl alcohols as the alkylating agents to afford the corresponding diarylmethane and triarylmethane derivatives in high yields. The scope and limitation of the reaction with respect to catalyst and substrates variation has been studied in detail.

  11. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  12. Epistemological barriers to radical behaviorism

    Science.gov (United States)

    O'Donohue, William T.; Callaghan, Glenn M.; Ruckstuhl, L. E.

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers. PMID:22478314

  13. Efficacy of postmilking disinfection with benzyl alcohol versus lodophor in the prevention of new intramammary infections in lactating cows.

    Science.gov (United States)

    Erskine, R J; Sears, P M; Bartlett, P C; Gage, C R

    1998-01-01

    Five Michigan dairy herds participated in a split-herd study to compare the efficacy of two postmilking teat dips in the prevention of new intramammary infections (IMI) in lactating cows. Three hundred seventy cows were assigned to 4% benzyl alcohol, and 387 cows were assigned to 1% iodophor germicidal teat dip. The teat dips were applied by directly immersing the teats immediately after milking. Once a group was assigned to a teat dip, cows in that group maintained on that same teat dip throughout the trial. Total new IMI numbered 254 and 201 for cows treated with benzyl alcohol and iodophor germicidal teat dip, respectively. Staphylococcus spp. (52.0%), Staphylococcus aureus (20.1%), and Corynebacterium bovis (12.2%) were the predominant pathogens that caused new IMI in cows treated with benzyl alcohol. Staphylococcus spp., Staph. aureus, and C. bovis, respectively, were the pathogens responsible for 69.7, 12.4, and 4.5% of the new IMI in cows treated with iodophor. The incidences of new IMI caused by Staph. aureus (0.66 new IMI/100 milking quarters per mo), C. bovis (0.38 new IMI/100 milking quarters per mo), and all pathogens (3.15 new IMI/100 milking quarters per mo) were higher in cows treated with benzyl alcohol than in cows treated with iodophor (0.29, 0.11, and 2.35 new IMI/100 milking quarters per mo, respectively). Incidence of new IMI did not differ between groups for other pathogens. One percent iodophor prevented new IMI caused by contagious pathogens more effectively than did benzyl alcohol.

  14. Radical democratic politics and feminism

    Directory of Open Access Journals (Sweden)

    Martínez Labrin, Soledad

    2006-05-01

    Full Text Available In the article I present a reflection around the radical democratic project proposed by Chantal Mouffe and Ernesto Laclau. Specifically, I examine the application of the project in the context of the “new social movements” and especially, of feminist movement. I state the need of drawing attention to universalism and essentialism as the main obstacles to generate a collective proposal without margins. Nevertheless, doubts remind about the possibility of building up a feminism tailored by the radical democratic project, in a stage in which the political action of such a movement is characterized by categories that are closed and crystallized

  15. Vaginal radical trachelectomy: an update.

    Science.gov (United States)

    Plante, Marie

    2008-11-01

    The vaginal radical trachelectomy has emerged as a valuable fertility-preserving treatment option for young women with early-stage disease. Cancer-related infertility is associated with feelings of depression, grief, stress, and sexual dysfunction. Data have shown that the overall oncological outcome is safe and that the obstetrical outcome is promising. In this article, we analyze the data on the vaginal radical trachelectomy published over the last 10 years in the context of what we have learned, what issues remain unclear, and what the future holds.

  16. Benzyl 2-β-glucopyranosyloxybenzoate, a new phenolic acid glycoside from Sarcandra glabra.

    Science.gov (United States)

    Wu, Haifeng; Hu, Xiaoru; Zhang, Xiaopo; Chen, Shilin; Yang, Junshan; Xu, Xudong

    2012-05-04

    From the whole plant of Sarcandra glabra, a new phenolic acid glycoside, benzyl 2-β-glucopyranosyloxybenzoate (1), together with seven known compounds including eleutheroside B₁ (2), 5-O-caffeoylshikimic acid (3), (-)-(7S, 8R)-dihydrodehydrodiconiferyl alcohol (4), (-)-(7S, 8R)-dihydrodehydrodiconiferyl alcohol 9-, 9′- and 4-O-α-D-glucopyranoside (5-7), and (-)-(7S, 8R)-5-methoxydihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (8) was isolated. Their structures were elucidated by spectral analysis including 1D-, 2D-NMR and HR-ESI-MS. Compound 2 was found to exhibit potent cytotoxic activity against BGC-823 and A2780 cancer cell lines using MTT method with IC₅₀ value of 2.53 and 1.85 μM, respectively.

  17. Formation of Benzyl Carbanion in Collision-Induced Dissociation of Deprotonated Phenylalanine Homologues.

    Science.gov (United States)

    Sekimoto, Kanako; Matsuda, Natsuki; Takayama, Mitsuo

    2014-01-01

    The fragmentation behavior of deprotonated L-phenylalanine (Phe) and its homologues including L-homophenylalanine (HPA) and L-phenylglycine (PG) was investigated using collision-induced dissociation mass spectrometry coupled with a negative ion atmospheric pressure corona discharge ionization (APCDI) technique. The deprotonated molecules [M-H](-) fragmented to lose unique neutral species, e.g., the loss of NH3, CO2, toluene and iminoglycine for [Phe-H](-); styrene and ethenamine/CO2 for [HPA-H](-); and CO2 for [PG-H](-). All of the fragmentations observed are attributable to the formation of intermediates and/or product ions which include benzyl carbanions having resonance-stabilized structures. The carbanions are formed via proton rearrangement through a transition state or via a simple dissociation reaction. These results suggest that the principal factor governing the fragmentation behavior of deprotonated Phe homologues is the stability of the intermediate and/or product ion structures.

  18. Cytotoxic C-benzylated chalcone and other constituents of Ellipeiopsis cherrevensis.

    Science.gov (United States)

    Wirasathien, Lalita; Pengsuparp, Thitima; Moriyasu, Masataka; Kawanishi, Kazuko; Suttisri, Rutt

    2006-06-01

    A new natural C-benzylated chalcone, 2',4'-dihydroxy-3'-(2-hydroxybenzyl)-6'-methoxychalcone (2), along with two other flavonoids, tiliroside and kaempferol 3-O-rutinoside, and an oxoaporphine alkaloid, lanuginosine were isolated from the aerial parts of Ellipeiopsis cherrevensis (Annonaceae). Two known polyoxygenated cyclohexene derivatives, ferrudiol and zeylenol, and a new analog, ellipeiopsol D, were also isolated. The chalcone 2 exhibited cytotoxic activity against human small-cell lung-cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines with IC50 values of 1.40, 5.31 and 13.92 microg/mL, respectively. This compound also showed antimalarial activity against Plasmodium falciparum with an IC50 value of 7.1 microg/mL as well as antimicrobacterial activity against Mycobacterium tuberculosis with a MIC of 25 mg/mL.

  19. SYNTHESIS AND CHARACTERIZATION OF SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES CONTAINING BENZYL ETHER LINKING UNITS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Side chain liquid crystalline polysiloxanes containing benzyl ether linking units were synthesized by the hydrosilylation of poly(methylhydrosiloxane) with a series of 4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy)-4'-allyloxybiphenyl (M1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M3), 4-(4-butoxybenzyloxy)-4'-allyloxybiphenyl (M4), 4-(4-pentoxybenzyloxy)-4'-allyloxybiphenyl (Ms), 4-benzyloxy-4'-allyloxybiphenyl (M6)]. The phase behavior of monomeric and polymeric liquid crystals was characterized by differential scanning calorimetry and optical polarization microscopy where the groups are ranged from methoxy to pentoxy. Both the monomeric and polymeric liquid crystals exhibit liquid crystal behaviors.

  20. 17O NMR parameters of some substituted benzyl ethers components: Ab initio study

    Directory of Open Access Journals (Sweden)

    Mahdi Rezaei Sameti

    2016-09-01

    Full Text Available The 17O NMR chemical shielding tensors and chemical shift for a set of substituted benzyl ethers derivatives containing (methyl, ethyl, isopropyl, t-butyl, brome and lithium have been calculated. The molecular structures were fully optimized using B3LYP/6-31G(d,p. The calculation of the 17O shielding tensors employed the GAUSSIAN 98 implementation of the gauge-including atomic orbital (GIAO and continuous set of gauge transformations (CSGT by using 6-31G (d,p, 6-31++G(d,p and 6-311++G(d,p basis set methods at density functional levels of theories (DFT. The values determined using the GIAO and CSGT were found to give a good agreement with the experimental chemical shielding.

  1. New fatty acid, aromatic ester and monoterpenic benzyl glucoside from the fruits of Withania coagulans Dunal.

    Science.gov (United States)

    Ali, Abuzer; Jameel, Mohammad; Ali, Mohammed

    2015-01-01

    The fruits of Withania coagulans Dunal (family: Solanaceae) are sweet, sedative, emetic, alterative and diuretic; used to treat asthma, biliousness, strangury, wounds, dyspepsia, flatulent colic, liver complaints and intestinal infections in the indigenous system of medicine. Phytochemical investigation of the methanolic extract of W. coagulans fruits led to the isolation of a new fatty acid, an aromatic ester and a monoterpenic benzyl glucoside characterised as n-octatriacont-17-enoic acid (3), geranilan-10-olyl dihydrocinnamoate (4) and geranilan-8-oic acid-10-olyl salicyloxy-2-O-β-D-glucofuranosyl-(6″→1‴)-O-β-D-glucofuranosyl-6‴-n-octadec-9‴',11‴'-dienoate (5) along with two known fatty acids, n-dotriacont-21-enoic acid (1) and n-tetratriacontanoic acid (2). The structures of isolated phytoconstituents were established on the basis of 1D and 2D NMR, FT-IR, UV, and MS data and chemical means.

  2. Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol

    Science.gov (United States)

    Fei, Jingyuan; Sun, Lixian; Zhou, Cuifeng; Ling, Huajuan; Yan, Feng; Zhong, Xia; Lu, Yuxiang; Shi, Jeffrey; Huang, Jun; Liu, Zongwen

    2017-01-01

    The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of {O}_2- species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

  3. Isomerism in benzyl-DOTA derived bifunctional chelators: implications for molecular imaging.

    Science.gov (United States)

    Payne, Katherine M; Woods, Mark

    2015-02-18

    The bifunctional chelator IB-DOTA has found use in a range of biomedical applications given its ability to chelate many metal ions, but in particular the lanthanide(III) ions. Gd(3+) in particular is of interest in the development of new molecular imaging agents for MRI and is highly suitable for chelation by IB-DOTA. Given the long-term instability of the aryl isothiocyanate functional group we have used the more stable nitro derivative (NB-DOTA) to conduct a follow-up study of some of our previous work on the coordination chemistry of chelates of these BFCs. Using a combination of NMR and HPLC to study the Eu(3+) and Yb(3+) chelates of NB-DOTA, we have demonstrated that this ligand will produce two discrete regioisomeric chelates at the point at which the metal ion is introduced into the BFC. These regioisomers are defined by the position of the benzylic substituent on the macrocyclic ring: adopting an equatorial position either at the corner or the side of the [3333] ring conformation. These regioisomers are incapable of interconversion and are distinct, separate structures with different SAP/TSAP ratios. The side isomer exhibits an increased population of the TSAP isomer, pointing to more rapid water exchange kinetics in this regioisomer. This has potential ramifications for the use of these two regioisomers of Gd(3+)-BFC chelates in MRI applications. We have also found that, remarkably, there is little or no freedom of rotation about the first single bond extending from the macrocyclic ring to the benzylic substituent. Since this is the linkage through which the chelate is conjugated to the remainder of the molecular imaging probe, this result implies that there may be reduced local rotation of the Gd(3+) chelate within a molecular imaging probe. This implies that this type of BFC could exhibit higher relaxivities than other types of BFC.

  4. Complex conformational heterogeneity of the highly flexible O6-benzyl-guanine DNA adduct.

    Science.gov (United States)

    Wilson, Katie A; Wetmore, Stacey D

    2014-07-21

    The conformational preference of the O6-benzyl-guanine (BzG) adduct was computationally examined using nucleoside, nucleotide, and DNA models, which provided critical information about the potential mutagenic consequences and toxicity of the BzG adduct in our cells. Substantial conformational flexibility of the BzG moiety, including rotation of the bulky group with respect to the base and the internal conformation of the bulk moiety, is seen in the nucleoside and nucleotide models. This large conformational flexibility suggests the conformation adopted by BzG is dependent on the local environment of the BzG adduct. Upon incorporation of the adduct into the DNA helix, the BzG conformational flexibility is maintained. The range of BzG conformations adopted in DNA likely arises due to a combination of the long and flexible (-CH2-) linker, the small adduct size, and the lack of discrete interactions between the bulky moiety and G. Because of the conformational flexibility of the adduct, many DNA conformations are observed for BzG adducted DNA, including those not previously reported in the literature, and thus, a modified nomenclature for adducted DNA conformations is presented. Furthermore, the preferred conformation of BzG adducted DNA is greatly dependent on a number of factors, including the pairing nucleotide, the discrete interactions in the helix, and the solvation of the benzyl moiety. These factors in turn lead to a complicated mutagenic and toxic profile that may invoke pairing with natural C, mispairs, or deletion mutations, which is supported by previously reported experimental biochemical studies. Despite this complex mutagenic profile, pairing with C leads to the most stable helical structure, which is the first combined structural and energetic explanation for experimental studies reporting a higher rate of C incorporation than any other nucleobase upon BzG replication.

  5. Síntese de 2-iodobenzamidas e 3-(iodoacetamidobenzamidas ligadas à D-galactose e suas reações de carbociclização radicalar mediadas por hidreto de tri-n-butilestanho Synthesis of 2-iodobenzamides and 3-(iodoacetamidobenzamides linked to D-galactose and their tri-n-butyltin hydride-mediated radical carbocyclization reactions

    Directory of Open Access Journals (Sweden)

    Daniel Henriques Soares Leal

    2009-01-01

    Full Text Available Starting from methyl 6-O-allyl-4-azido-2,3-di-O-benzyl-4-deoxy-α-D-galactopyranoside, four new derivatives containing 2-iodobenzamido and 3-(iodoacetamidobenzamido groups were synthesized. These four compounds were submitted to tri-n-butyltin hydride mediated radical cyclization reactions, resulting in two macrolactams from 11- and 15-endo aryl radical cyclization. The corresponding four hydrogenolysis products were also obtained. The structures of the new compounds were elucidated by ¹H and 13C NMR spectroscopy, DEPT, COSY, HMQC and HMBC experiments.

  6. Radical Innovation and Network Evolution

    NARCIS (Netherlands)

    S.M.W. Phlippen (Sandra); M. Riccaboni

    2007-01-01

    textabstractThis paper examines how a radical technological innovation affects alliance formation of firms and subsequent network structures. We use longitudinal data of interfirm R&D collaborations in the biopharmaceutical industry in which a new technological regime is established. Our findings su

  7. Wild radical square zero algebras

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    It is shown that a radical square zero algebra is wild, if and only if it is of Corner's type, and it is strictly wild if and only if it is Endo-wild. This gives a negative answer to a problem posed by Simson.

  8. Is Radical Innovation Management Misunderstood?

    DEFF Research Database (Denmark)

    Kristiansen, Jimmi Normann; Gertsen, Frank

    2015-01-01

    This paper poses a critical view on radical innovation (RI) management research and practice. The study investigates how expected RI performance influences firms’ under- standing of their RI capability. RI performance is often based on output measures such as market shares or fiscal return...

  9. Exploring the Theories of Radicalization

    Directory of Open Access Journals (Sweden)

    Maskaliūnaitė Asta

    2015-12-01

    Full Text Available After the London bombings in July 2005, the concern of terrorism scholars and policy makers has turned to “home-grown” terrorism and potential for political violence from within the states. “Radicalization” became a new buzz word. This article follows a number of reviews of the literature on radicalization and offers another angle for looking at this research. First, it discusses the term “radicalization” and suggests the use of the following definition of radicalization as a process by which a person adopts belief systems which justify the use of violence to effect social change and comes to actively support as well as employ violent means for political purposes. Next, it proposes to see the theories of radicalization focusing on the individual and the two dimensions of his/her motivation: whether that motivation is internal or external and whether it is due to personal choice or either internal (due to some psychological traits or external compulsion. Though not all theories fall neatly within these categories, they make it possible to make comparisons of contributions from a variety of different areas thus reflecting on the interdisciplinary nature of the study of terrorism in general and radicalization as a part of it.

  10. Radical review of NHS funding.

    Science.gov (United States)

    1988-02-06

    The Government is to carry out a radical review of the way the NHS is funded, Prime Minister Margaret Thatcher confirmed last week. And she hinted that she herself would be taking a leading role in drawing up proposals for reform.

  11. Detecting Social Polarization and Radicalization

    DEFF Research Database (Denmark)

    Qureshi, Pir Abdul Rasool; Memon, Nasrullah; Wiil, Uffe Kock

    2011-01-01

    This paper proposes a novel system to detect social polarization and to estimate the chances of violent radicalization associated with it. The required processes for such a system are indicated; it is also analyzed how existing technologies can be integrated into the proposed system to fulfill...

  12. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-01-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of "narrow mental states"; that is, the idea that the mental content of an individual can be fully characterised without…

  13. Design and synthesis of novel 3-substituted-indole derivatives as selective H3 receptor antagonists and potent free radical scavengers.

    Science.gov (United States)

    Tang, Li; Zhao, Liying; Hong, Lingjuan; Yang, Fenyan; Sheng, Rong; Chen, Jianzhong; Shi, Ying; Zhou, Naimin; Hu, Yongzhou

    2013-10-01

    A series of novel 3-substituted-indole derivatives with a benzyl tertiary amino moiety were designed, synthesized and evaluated as H3 receptor antagonists and free radical scavengers for Alzheimer's disease therapy. Most of these synthesized compounds exhibited moderate to potent antagonistic activities in CREs driven luciferase assay. In particular, compound 2d demonstrated the most favorable H3 receptor antagonistic activity with the IC50 value of 0.049μM. Besides, it also displayed high binding affinity to H3 receptor (Ki=4.26±2.55nM) and high selectivity over other three histamine receptors. Moreover, 2d and other two 3-substituted indole derivatives 1d and 3d exerted potent ABTS radical cation scavenging capacities similar to melatonin. Above results illustrate that 2d is an interesting lead for extensive optimization to explore new drug candidate for AD therapy.

  14. Microwave-Assisted Improved Regioselective Synthesis of 12H-Benzopyrano[3,2-c][1]benzopyran-5-ones by Radical Cyclisation

    Directory of Open Access Journals (Sweden)

    Pradipta Kumar Basu

    2011-01-01

    Full Text Available Two new effective methodologies have been adopted for the preparation of 4-(2′-bromobenzyloxybenzopyran-7-ones 3(a–h. In the first methodology, 4-hydroxy[1]benzopyran-2-ones 1(a–d was alkylated with 2-bromobenzyl bromide 2a or 2-bromo-5-methoxy benzyl bromide 2b under phase transfer catalysis condition using lithium hydroxide/tetrabutyl ammonium bromide in N,N-dimethylformamide at 40–50°C and in the second method the microwave irradiation protocol has been exploited by simply mixing of 4-hydroxy[1]benzopyran-2-ones 1(a–d with 25% excess of 2-bromobenzyl bromide 2a or 2-bromo-5-methoxy benzyl bromide 2b. A catalytic amount of TBAB and potassium carbonate were added and irradiated in an open Erlenmeyer flask in a microwave oven for 4–10 min. The tributyltin-hydride-mediated radical cyclisation of 3(a–h was carried out under microwave irradiation to generate 12H-benzopyrano[3,2-c][1]benzopyran-5-ones 4(a–h in 78–88% yield and in this technique yields were significantly improved and reaction time was shortened compared to the previously reported conventional radical cyclisation method.

  15. Choice of Bond Dissociation Enthalpies on which to Base the Stabilization Energies of Simple Radicals: DH(R-H)is Preferred because DH(R-Me) is Perturbed by Changes in Chain Branching

    Energy Technology Data Exchange (ETDEWEB)

    Poutsma, Marvin L [ORNL

    2008-01-01

    The relative stabilization energies of radicals, SE(R ), along the simple series methyl/ethyl/i-propyl/t-butyl are known to vary in spread and even direction dependent on which dissociation enthalpies, DH(R-X), they are based on. Using a highly electronegative X is recognized as unwise, but it is not clear whether a choice of X = Me or X = R might not be preferred over the almost universal use of R = H. The enthalpies of isomerization of C4 radical pairs that vary only in the substitution pattern at the radical center but not in carbon skeleton illustrate that R = H is indeed the better choice. Comparisons in the context of recent predictive models for alkane and radical stability indicate that, while relative DH(R-H) values highlight the desired difference in substitution pattern at the radical center, relative DH(R-Me) values are perturbed by differences in skeletal branching or protobranching which are well-known to affect thermochemistry. As a result, SE(R ) values derived from relative DH(R-Me) values are consistently too small. The same pattern is illustrated for prim, sec, and tert allylic and benzylic radicals (larger SE(R )) and for the parent vinyl, phenyl, and ethynyl radicals (negative SE(R )).

  16. Reaction between protein radicals and other biomolecules

    DEFF Research Database (Denmark)

    Østdal, Henrik; Davies, Michael Jonathan; Andersen, Henrik J

    2002-01-01

    oil-in-water emulsion resulted in additional formation of lipid hydroperoxides and conjugated dienes. The results clearly show that protein radicals have to be considered as dynamic species during oxidative processes in biological systems and that protein radicals should not be considered as end-products......The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2....... Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid...

  17. A green and efficient oxidation of benzylic alcohols using H2O2 catalyzed by Montmorillonite-K10 supported MnCl2

    Institute of Scientific and Technical Information of China (English)

    Cholam Reza Najafi

    2010-01-01

    Primary and secondary benzylic alcohols were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by Montmorillonite-K10 supported manganese(Ⅱ) chloride.

  18. Trapping of carbolithiation-derived tertiary benzylic α-lithio piperidines with carbon electrophiles: Controlling the formation of α-amino quaternary and vicinal stereocenters.

    Science.gov (United States)

    Beng, Timothy K; Fox, Nathan; Bassler, Daniel P; Alwali, Amir; Sincavage, Kayla; Silaire, Ann Wens V

    2015-08-28

    The interception of carbolithiation-derived tertiary benzylic α-lithio piperidines with carbon electrophiles, under HMPA-mediated conditions, has led to the diastereoselective synthesis of vicinally functionalized piperidines bearing α-amino quaternary stereocenters.

  19. Oxygen free radicals in rheumatoid arthritis

    NARCIS (Netherlands)

    P. Biemond (Pieter)

    1986-01-01

    textabstractCurrent knowledge strongly suggests that oxygen free radicals are involved in the pathogenesis of RA. Additional information about the mechanism of free radical attack is necessary in order to find out if interaction with the mechanism of free radical damage can be used in the treatment

  20. Novel Synthesis and Anti-HIV-1 Activity of 2-Arylthio-6-benzyl-2,3-dihydro-1H-pyrimidin-4-ones (Aryl S-DABOs)

    DEFF Research Database (Denmark)

    Aly, Youssef L.; Pedersen, Erik Bjerreg.; La Colla, Paolo;

    2007-01-01

    The synthesis and the anti-HIV-1 activity of a series of 2-arylthio-6-benzyl-2,3-dihydro-1H-pyrimidin-4-ones (aryl S-DABOs) are reported. These compounds were synthesized via a coupling reaction of the corresponding 6-benzyl-2-thiouracils with aryl iodides in the presence of neocuproine hydrate......, copper(I) iodide, and sodium tert-butoxide. Target compounds showed moderate activity against HIV-1....

  1. PPA-SiO2 Catalyzed Multi-component Synthesis of N-[α-(β-Hydroxy-α-naphthyl)(benzyl)]O-Alkyl Carbamate Derivatives

    Institute of Scientific and Technical Information of China (English)

    SHATERIAN,Hamid Reza; HOSSEINIAN,Asghar; GHASHANG,Majid

    2009-01-01

    Silica-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multi-component condensation reaction of benzaldehydes,2-naphthol,and methyl/benzyl carbamate to afford the corresponding N-[α-(β-hydroxy-α-naphthyl)(benzyl)]O-alkyl carbamate derivatives in good to excellent yields.This new approach consistently has the advantage of short reaction time,high conversions,clean reaction profiles,and simple experimental and work-up procedures.

  2. DNA binding hydroxyl radical probes

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Vicky J.; Konigsfeld, Katie M.; Aguilera, Joe A. [Department of Radiology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States); Milligan, Jamie R., E-mail: jmilligan@ucsd.edu [Department of Radiology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States)

    2012-01-15

    The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different chromophores, which produce fluorescent products when hydroxylated. Of these, the coumarin system suffers from the fewest disadvantages. We have therefore examined its behavior when linked to a cationic peptide ligand designed to bind strongly to DNA. - Highlights: > Examined four aromatic groups as a means to detect hydroxyl radicals by fluorescence. > Coumarin system suffers from the fewest disadvantages. > Characterized its reactivity when linked to a hexa-arginine peptide.

  3. Highly durable photochromic radical complexes having no steric protections of radicals.

    Science.gov (United States)

    Kobayashi, Yoichi; Mishima, Yasuhiro; Mutoh, Katsuya; Abe, Jiro

    2017-04-21

    Steric protection groups are usually necessary for stable radicals. However, here, we developed novel photochromic radical complexes which generate sterically unprotected imidazolyl and phenoxyl radicals upon UV light irradiation based on the phenoxyl-imidazolyl radical complex (PIC) framework. These photochromic compounds show excellent durability against repeated irradiation of intense nanosecond laser pulses even in polar protic solvents, such as ethanol.

  4. Geoscientists and the Radical Middle

    Science.gov (United States)

    Tinker, S. W.

    2015-12-01

    Addressing the great challenges facing society requires industry, government, and academia to work together. I call this overlap space, where compromises are made and real solutions determined, the Radical Middle. Radical because it can appear at times as if the loudest and most publicly influential voices lie outside of the actual solution space, content to provoke but not problem-solve. One key area where geoscientists can play a lead role in the Radical Middle is in the overlap between energy, the environment, and the economy. Globally, fossil fuels still represent 85% of the aggregate energy mix. As existing conventional oil and natural-gas reservoir production continues to slowly decline, unconventional reservoirs, led today by shale and other more expensive resources, will represent a growing part of the oil and gas production mix. Many of these unconventional reservoirs require hydraulic fracturing. The positive economic impact of hydraulic fracturing and associated natural gas and oil production on the United States economy is well documented and undeniable. Yet there are environmental concerns about fracking, and some states and nations have imposed moratoria. This energy-environment-economy space is ideal for leadership from the geosciences. Another such overlap space is the potential for geoscience leadership in relations with China, whose economy and global presence continue to expand. Although China is building major hydropower and natural-gas power plants, as well as nuclear reactors, coal is still king—with the associated environmental impacts. Carbon sequestration—onshore in brine and to enhance oil recovery, as well as offshore—could prove viable. It is vital that educated and objective geoscientists from industry, government, and academia leave their corners and work together in the Radical Middle to educate the public and develop and deliver balanced, economically sensible energy and environmental strategies.

  5. Theoretical Studies of Water's and Methanol's Effects on Alcoholysis of N-Benzyl-3-oxo-β-sultam

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The mechanisms about the water's and methanol's effects on the alcoholysis of N-benzyl-3-oxo-β-sultam together with their differences have been studied by using density functional theory at the B3LYP/6-31G* level. The results, in comparison with a previous study on the relative reaction without the assistance of water and methanol, show that the added water or methanol can remarkably reduce the energy barrier of alcoholysis reaction of N-benzyl-3-oxo-β-sultam and the most favorite pathway is the breaking of C-N bond instead of S-N. It is also found that the reaction energy barrier of methanol-assisted alcoholysis is a little higher than that of the water-assisted one.

  6. 苄基红景天的工艺改进%Improved Synthesis of Benzyl-salidroside

    Institute of Scientific and Technical Information of China (English)

    张智勇; 张丽娟; 张达盼; 李正年; 王玉玲

    2011-01-01

    The benzyl-salidroside, a key intermediate for salidroside, was prepared from anhydrous glucose and tyrosol by acylation, benzylation and glucosidation in overall yield of 21.8%. The structure of the target compound was characterized with IR and 1H NMR.%以无水葡萄糖和对羟基苯乙醇为起始原料,经过乙酰化、苄基保护、苷化三步反应合成了苄基红景天,总收率21.8%;考察了反应物料配比、干燥条件、反应时间对收率的影响.目标化合物的结构经IR和1H NMR确证.改进后的工艺降低了合成成本,简单可行,适合工业化生产.

  7. Synthesis of liquid crystalline 4H-benzo[1,2,4]thiadiazines and generation of persistent radicals.

    Science.gov (United States)

    Zienkiewicz, Józef; Fryszkowska, Anna; Zienkiewicz, Katarzyna; Guo, Fengli; Kaszynski, Piotr; Januszko, Adam; Jones, David

    2007-04-27

    Four substituted 4H-benzo[1,2,4]thiadiazines 2 were prepared by condensation of the appropriate anilines and benzonitriles followed by oxidative cyclization. The preparation of three fluorinated derivatives 2b-2d proceeded smoothly, while the synthesis of 2a was problematic, presumably due to the relatively high electron density of the benzene ring. The four-ring derivatives 2c and 2d exhibited liquid crystalline properties (2c: Cr 95 SmA 158 I and 2d: Cr 142 SmA 212 I). 4H-Benzo[1,2,4]thiadiazines 2 were oxidized with AgO to generate the corresponding persistent radicals 1 (g=2.0057). The stability of the radicals followed the order 1b approximately 1d>1c>1a, and the two fluorinated radicals 1b and 1d were isolated as crude solids. The lower stability of 1c is presumably due to the presence of the reactive benzylic CH position, and 1a lacks the stabilizing effect of the three fluorine atoms. ESR spectra for 1 were simulated using DFT-derived hfcc as the starting point.

  8. Gold Nanorod@TiO2 Yolk-Shell Nanostructures for Visible-Light-Driven Photocatalytic Oxidation of Benzyl Alcohol.

    Science.gov (United States)

    Li, Ang; Zhang, Peng; Chang, Xiaoxia; Cai, Weiting; Wang, Tuo; Gong, Jinlong

    2015-04-24

    Fine gold nanorod@TiO2 yolk-shell catalysts are synthesized by an improved silica template method. With a hollow TiO2 shell and a unique tunable cylindrical gold core, the catalyst exhibits a high surface area and a wide range of photoabsorption, from ultraviolet to near infrared. The remarkable photochemical activity is obtained when such catalyst is utilized to oxidize benzyl alcohol.

  9. NBS/DBU mediated one-pot synthesis of α-acyloxyketones from benzylic secondary alcohols and carboxylic acids.

    Science.gov (United States)

    Zhu, Minghui; Wei, Wei; Yang, Daoshan; Cui, Hong; Cui, Huanhuan; Sun, Xuejun; Wang, Hua

    2016-11-22

    A simple and efficient one-pot NBS/DBU-mediated method has been developed for the synthesis of α-acyloxyketones from various benzylic secondary alcohols and carboxylic acids. Through this methodology, a series of α-acyloxyketones could be obtained in good to excellent yields under mild conditions. Importantly, this new reaction avoids the direct usage of toxic metal catalysts or potentially dangerous peroxide oxidants.

  10. Cobalt salophen complex supported on magnetic nanoparticles as an efficient reusable catalyst for oxidation of benzylic alcohols

    Directory of Open Access Journals (Sweden)

    Mozhgan Afshari

    2014-01-01

    Full Text Available A novel and general method has been developed for oxidation of benzylic alcohols using magnetic nanoparticles immobilized salophen Co(II as an efficient and recyclable catalyst. The structural and magnetic properties of catalyst are identified by transmission electron microscopy (TEM, vibrating sample magnetometer (VSM instruments. FT-IR, and XRD. Nanocatalyst can be easily recovered by a magnetic field and reused for subsequent reactions for at least 5 times with less deterioration in catalytic activity.

  11. Dendritic Macroinitiator for the Ring-Opening Polymerization of γ-Benzyl L-Glutamate N-Carboxyanhydride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By using OH-terminated polyarylether dendrimer and N-Fmoc-glycine as raw materials, the dendritic polyarylether 2-aminoacetate (G3-NH2) was synthesized via two step reactions. G3-NH2 as a macroinitiator for the ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride was investigated. It is found that the resulting copolymers possessed relatively high molecular weight and narrow molecular weight distribution (1.12< Mw/Mn<1.28).

  12. Fe3+-Exchanged Titanate Nanotubes: A New Kind of Highly Active Heterogeneous Catalyst for Friedel-Crafts Type Benzylation

    Directory of Open Access Journals (Sweden)

    Yunchen Du

    2015-01-01

    Full Text Available Heterogeneous catalysis for Friedel-Crafts type benzylation has received much attention in recent years due to its characteristic of environmental benefits. In this paper, titanate nanotubes (TNTs were employed as heterogeneous catalyst support, and a new kind of Fe3+-exchanged titanate nanotubes (Fe-TNTs catalyst with highly dispersed ferric sites was constructed by an ion exchange technique. The obtained catalyst was systematically characterized by XRD, TEM, N2 adsorption, XPS, and UV-vis spectra. As expected, Fe-TNTs showed excellent catalytic activities in the benzylation of benzene and benzene derivatives. The recycling tests for Fe-TNTs were also carried out, where the reason for the gradually decreased activity was carefully investigated. Superior to some reported catalysts, the catalytic ability of used Fe-TNTs could be easily recovered by ion exchange again, indicating that Fe-TNTs herein were a highly active and durable heterogeneous catalyst for Friedel-Crafts type benzylation. These results might be helpful for the design and preparation of novel heterogeneous catalysts by combining the structural advantages of titanate nanotubes and active metal ions.

  13. Identification of Active Phase for Selective Oxidation of Benzyl Alcohol with Molecular Oxygen Catalyzed by Copper-Manganese Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Roushown Ali

    2013-01-01

    Full Text Available Catalytic activity of copper-manganese mixed oxide nanoparticles (Cu/Mn = 1 : 2 prepared by coprecipitation method has been studied for selective oxidation of benzyl alcohol using molecular oxygen as an oxidizing agent. The copper-manganese (CuMn2 oxide catalyst exhibited high specific activity of 15.04 mmolg−1 h−1 in oxidation of benzyl alcohol in toluene as solvent. A 100% conversion of the benzyl alcohol was achieved with >99% selectivity to benzaldehyde within a short reaction period at 102°C. It was found that the catalytic performance is dependent on calcination temperature, and best activity was obtained for the catalyst calcined at 300°C. The high catalytic performance of the catalyst can be attributed to the formation of active MnO2 phase or absence of less active Mn2O3 phase in the mixed CuMn2 oxide. The catalyst has been characterized by powder X-ray diffraction (XRD, thermogravimetric analysis (TGA, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Brunauer Emmett-Teller (BET surface area measurement, and Fourier transform infrared (FT-IR spectroscopies.

  14. LETTING GO: DE-RADICALIZATION IN EGYPT

    Directory of Open Access Journals (Sweden)

    Zeynep Kaya

    2016-03-01

    Full Text Available The literature on the causes of how terrorist organizations are formed and how counter terrorism measures can be more effective is immense. What is novel in terrorism literature is de-radicalization in terrorist organizations. This paper hopes to shed light on the de-radicalization process in terrorist organizations based in Egypt. In order to achieve that goal, the first part of the paper will deal with the de-radicalization process. The second part will briefly describe the major radical terrorist organizations that are effective in Egypt. The last part will combine the two parts and bring in suggestions on the de-radicalization process itself. Terrorism and de-radicalization are complicated threats to nearly all societies. Therefore, it is important to go beyond security and intelligence approaches and take proactive measures. It is best to view what is de-radicalization and how it can be achieved.

  15. Oxidative stress, free radicals and protein peroxides.

    Science.gov (United States)

    Gebicki, Janusz M

    2016-04-01

    Primary free radicals generated under oxidative stress in cells and tissues produce a cascade of reactive secondary radicals, which attack biomolecules with efficiency determined by the reaction rate constants and target concentration. Proteins are prominent targets because they constitute the bulk of the organic content of cells and tissues and react readily with many of the secondary radicals. The reactions commonly lead to the formation of carbon-centered radicals, which generally convert in vivo to peroxyl radicals and finally to semistable hydroperoxides. All of these intermediates can initiate biological damage. This article outlines the advantages of the application of ionizing radiations to studies of radicals, with particular reference to the generation of desired radicals, studies of the kinetics of their reactions and correlating the results with events in biological systems. In one such application, formation of protein hydroperoxides in irradiated cells was inhibited by the intracellular ascorbate and glutathione.

  16. Glucuronoyl Esterase Screening and Characterization Assays Utilizing Commercially Available Benzyl Glucuronic Acid Ester

    Directory of Open Access Journals (Sweden)

    Hampus Sunner

    2015-09-01

    Full Text Available Research on glucuronoyl esterases (GEs has been hampered by the lack of enzyme assays based on easily obtainable substrates. While benzyl d-glucuronic acid ester (BnGlcA is a commercially available substrate that can be used for GE assays, several considerations regarding substrate instability, limited solubility and low apparent affinities should be made. In this work we discuss the factors that are important when using BnGlcA for assaying GE activity and show how these can be applied when designing BnGlcA-based GE assays for different applications: a thin-layer chromatography assay for qualitative activity detection, a coupled-enzyme spectrophotometric assay that can be used for high-throughput screening or general activity determinations and a HPLC-based detection method allowing kinetic determinations. The three-level experimental procedure not merely facilitates routine, fast and simple biochemical characterizations but it can also give rise to the discovery of different GEs through an extensive screening of heterologous Genomic and Metagenomic expression libraries.

  17. SOME BENZYL CARBOXYLATO DERIVATIVES AND ADDUCTS: SYNTHESIS, INFRARED AND NMR STUDIES

    Directory of Open Access Journals (Sweden)

    Daouda Ndoye

    2014-05-01

    Full Text Available Cy2NH2BzCO2•SnPh3Cl, Bz2NH2BzCO2•SnPh3Cl, BzCO2SnPh3•SnPh3Cl•1/4Bz2NH2Cl, Bz2NH2BzCO2•SnPhCl(OH2, Bz2NH2BzCO2•SnBu2Cl2, [BzCO2SnPh3][SnPhCl3•EtOH•H2O] adducts and complexes have been obtained on allowing Cy2NH2BzCO2 or Bz2NH2BzCO2•4H2O to react respectively with SnPh3Cl, SnPh2Cl2 or SnBu2Cl2 in specific ratios. The molecular structures of these compounds have been determined on the basis of infrared and NMR data. The suggested structures are discrete, dimers and tetramer, the tin atom being tetra-, penta- and hexacoordinated; the benzyl carboxylate anions are monodentate, bidentate and chelating and the cations involved in hydrogen bonds.

  18. Pertumbuhan Plantlet Anggrek Cattleya sp. dengan Perlakuan Benzyl Amino Purine pada Media Dasar Pupuk Daun Modifikasi

    Directory of Open Access Journals (Sweden)

    HESTIN YUSWANTI

    2015-09-01

    Full Text Available Growth of Plantlets of Cattleya Orchid on The Fooliar Fertilizer-Based Medium added with Benzyl Amino Purine. The aim of the current research was to investigate the appropriate concentrationof plant growth regulator BAP on the growth of Cattleya plantlet. The experiment was utilized a Randomized Completely Design with five treatments and six replications. The basal medium used was modification of foliar fertilizer of Growmore (trade mark with addition of fish emulsion, Vitamin B1 and active charcoal. BAP concentration used as treatment were 0 ppm, 0.5 ppm, 1.0 ppm, 1.5 ppm and 2.0 ppm. Variables observed were height, leaf number, root number, root length, fresh weight and dry weight of plantlets. The result showed that concentration of 1 ppm BAP resulted in the highest value for plantlet height (5.67 cm, leaf number (4.67, root length (2.07 cm, fresh weight (0.36 g and dry weight (0.043 g.

  19. Effect of Isotacticity of Linear Poly(N-isopropylacrylamide) on its Gelation in Benzyl Alcohol

    Indian Academy of Sciences (India)

    CHANDRA SEKHAR BISWAS; KHEYANATH MITRA; SHIKHA SINGH; DINESH K PATEL; BISWAJIT MAITI; PRALAY MAITI; BISWAJIT RAY

    2016-06-01

    Thermoreversible gelation of three different isotactic linear poly(N-isopropylacrylamide) (PNIPAM)s having meso dyad (m) values 62, 68 and 81% has been observed in benzyl alcohol. All the gels weretransparent in nature. SEM image of the dried gels showed fibrillar network morphology. Melting temperatureof the gels gradually increased with the increase in the concentration. XRD data of dry polymers and their correspondingdry gels showed shifting in the peak positions. Rheological study showed that stronger gels wereformed with increasing isotacticity of PNIPAM while lower isotactic sample exhibited typical polymer meltrheology. The formation of a plunge in the storage modulus as well as in the viscosity plot at the same frequencyrange indicates the reversible nature of the structure breaking/reformation under frequency sweep. Moreover,the mechanical strength of the gel decreased with increase in temperature. UV-Vis kinetic study also indicatedthe change in the conformation and aggregation of PNIPAM chains during gelation. Molecular modelling calculationshowed that the number of solvent molecules involved in forming gel (polymer-solvent compound)decreased with the increase in the isotacticity of the polymer. Gelation rate of these gels was studied as a functionof temperature, concentration and isotacticity using test-tube tilting method. It increased with the increasein the concentration and isoacticity of the polymer, and with the decrease in the temperature. Critical gelationconcentration of the gel gradually increased with the decrease in the isotacticity and with the increase in thetemperature. All these experimental results indicated that gelation occurs presumably through polymer-solventcompound formation.

  20. Isolation and identification of 4-α-rhamnosyloxy benzyl glucosinolate in Noccaea caerulescens showing intraspecific variation.

    Science.gov (United States)

    de Graaf, Rob M; Krosse, Sebastian; Swolfs, Ad E M; te Brinke, Esra; Prill, Nadine; Leimu, Roosa; van Galen, Peter M; Wang, Yanli; Aarts, Mark G M; van Dam, Nicole M

    2015-02-01

    Glucosinolates are secondary plant compounds typically found in members of the Brassicaceae and a few other plant families. Usually each plant species contains a specific subset of the ∼ 130 different glucosinolates identified to date. However, intraspecific variation in glucosinolate profiles is commonly found. Sinalbin (4-hydroxybenzyl glucosinolate) so far has been identified as the main glucosinolate of the heavy metal accumulating plant species Noccaea caerulescens (Brassicaceae). However, a screening of 13 N. caerulescens populations revealed that in 10 populations a structurally related glucosinolate was found as the major component. Based on nuclear magnetic resonance (NMR) and mass spectrometry analyses of the intact glucosinolate as well as of the products formed after enzymatic conversion by sulfatase or myrosinase, this compound was identified as 4-α-rhamnosyloxy benzyl glucosinolate (glucomoringin). So far, glucomoringin had only been reported as the main glucosinolate of Moringa spp. (Moringaceae) which are tropical tree species. There was no apparent relation between the level of soil pollution at the location of origin, and the presence of glucomoringin. The isothiocyanate that is formed after conversion of glucomoringin is a potent antimicrobial and antitumor agent. It has yet to be established whether glucomoringin or its breakdown product have an added benefit to the plant in its natural habitat.

  1. Enhancement of cisplatin cytotoxicity by benzyl isothiocyanate in HL-60 cells.

    Science.gov (United States)

    Lee, Younghyun; Kim, Yang Jee; Choi, Young Joo; Lee, Joong Won; Lee, Sunyeong; Chung, Hai Won

    2012-07-01

    Cis-diamminedichloroplatinum (II) (cisplatin) is one of the most widely used chemotherapeutic drugs, but its effectiveness is limited by tumor cell resistance and the severe side effects it causes. One strategy for overcoming this problem is the concomitant use of natural dietary compounds as therapeutic agents. Benzyl isothiocyanate (BITC) is a promising chemopreventive agent found in cruciferous vegetables and papaya fruits. The aim of this study was to investigate the effects of BITC on cisplatin-induced cytotoxicity in human promyelocytic leukemia cells and normal human lymphocytes. The combined treatment of HL-60 cells with BITC followed by cisplatin (BITC/cisplatin) caused a significant decrease in cell viability. BITC also increased apoptotic cell death compared to cisplatin treatment alone. In normal human lymphocytes, BITC did not enhance the cytotoxic effects of cisplatin. Cellular exposure to BITC/cisplatin increased reactive oxygen species (ROS) generation but decreased the total glutathione (GSH) level in HL-60 cells. Pretreatment of HL-60 cells with N-acetylcysteine or glutathione monoethyl ester effectively decreased BITC/cisplatin-induced cell death. The addition of the extracellular signal-regulated kinase (ERK) inhibitor PD98059 abolished BITC/cisplatin-induced apoptosis. Taken together, our results suggest that BITC enhances cisplatin-induced cytotoxicity through the generation of ROS, depletion of GSH, and ERK signaling in HL-60 cells.

  2. Piezoelectric property of hot pressed electrospun poly( γ-benzyl- α, L-glutamate) fibers

    Science.gov (United States)

    Ren, Kailiang; Wilson, William L.; West, James E.; Zhang, Q. M.; Yu, S. Michael

    2012-06-01

    Since the 1960s, the piezoelectricity in biopolymers (e.g. proteins and polynucleotides) has attracted considerable scientific attention. In particular, poly(glutamate)s have been one of the most popular targets for this research due to their well-defined helical structure and permanent polarity along the helical axis. To date, films of poly(glutamate)s have been shown to exhibit piezoelectricity only in shear mode (d14), mainly due to the limitation in fabricating electrically poled polymer samples. This paper describes a combined electrospinning and hot press method that allows production of poled poly( γ-benzyl- α,L-glutamate) (PBLG) films with piezoelectricity in all d33, d31 and d14 modes for the first time. It is found that this PBLG film belongs to the matrix structure of C∞ v group, which is the same as that of poled PVDF film. The moderately high piezoelectric coefficients in both d33 and d14 modes as well as their thermal stability make the poled PBLG film an excellent candidate for use in flexible transducers and small energy harvesting devices.

  3. Online radicalization: the net or the netizen?

    Directory of Open Access Journals (Sweden)

    Femi Richard Omotoyinbo

    2014-10-01

    Full Text Available Purpose - Radicalization has gained some unusual prominence in the academic circles; maintaining a generic existence not only in the political sector. And with the advent of the Information Communication Technology (ICT, radicalization has begun to have some virtual dimension even in the remotest of human communities. This study seeks to mobilize a universal awareness on the collective urgency to oppose Online Radicalization (a radicalization that happens through the internet due to its propensity to engendering conflicts. It also aims at identifying the principal cause of online radicalization and steer a clear course for a practical reversal in the systems of online radicalization.Design/methodology/approach - The study is divided into three primary parts. The general notion of radicalization is the focus of the first part; which is further analysed into the levels of online radicalization with its accompanying developments and segments. The second part utilizes analytic and historical method to pinpoint the principal cause of online radicalization amidst the suspected causal factors (the Net and the Netizen. The final part analytically focuses on the Netizen (a user/citizen of the internet as the primary cause of online radicalization, and how the global community can bring about a corresponding change in the Net by the application of some measures on the Netizen.Findings - By virtue of the analytic plus historical methods employed by this study; it was initially identified that radicalization is basically having two versions which are online and offline. Further emphasis on the online version reveals that its existence is only made possible by the availability of the internet (the Net. Since the Net is a global phenomenon online radicalization is considered to be worldwide: a menace of globalization. However, the study later indicated that the Net is a facilitator and a cause of online radicalization. A view was deduced that the Netizen is

  4. Remembering Dutch-Moluccan radicalism

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2016-01-01

    This article examines memory politics in relation to radical actions of young Dutch-Moluccans, more specifically a train hijacking in 1977 at the village of De Punt in the Netherlands. The article examines how these historical events were remembered in the drama-documentary television film, De Punt......, as well as in user-generated comments in an online discussion. The television film represented an inclusive memory culture that made room for the difficult memories of all parties involved, including the radicalised, young hijackers. Based on a multidimensional model of mass media reception, the analysis...

  5. Radical conservatism and Danish imperialism

    DEFF Research Database (Denmark)

    2013-01-01

    on the basis of a close reading of their imperialist program in the pamphlet Danmark Udslettes! from 1918. Rige had been a vague term for the larger Danish polity that originated in a pre-national conceptualization of the polity as a realm. The article suggests that rige-as-realm was translated by the radical...... to signify the ambition of being a great power, the spiritual elevation of the nation through the transcendence of the decaying liberal modernity. The program addressed the tension between a conservative political attitude and modernity and thus signified a kind of reactionary modernism, which rejected...

  6. Laser spectroscopy of hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P. [Harvard Univ., Cambridge, MA (United States)

    1993-12-01

    The author reports the application of supersonic jet flash pyrolysis to the specific preparation of a range of organic radicals, biradicals, and carbenes in a skimmed molecular beam. Each species was produced cleanly and specifically, with little or no secondary reactions by the thermal dissociation of appropriately designed and synthesized organic precursors. Photoelectron spectra of the three isomeric C{sub 3}H{sub 2} carbenes, ortho-benzyne, and the {alpha},3-dehydrotoluene biradical, were used to establish adiabatic ionization potentials for use in thermochemical determinations.

  7. Aromatic-radical oxidation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Glassman, I.; Brezinsky, K. [Princeton Univ., NJ (United States)

    1993-12-01

    The research effort has focussed on discovering an explanation for the anomalously high CO{sub 2} concentrations observed early in the reaction sequence of the oxidation of cyclopentadiene. To explain this observation, a number of plausible mechanisms have been developed which now await experimental verification. One experimental technique for verifying mechanisms is to probe the reacting system by perturbing the radical concentrations. Two forms of chemical perturbation of the oxidation of cyclopentadiene were begun during this past year--the addition of NO{sub 2} and CO to the reacting mixture.

  8. Radical constructivism: Between realism and solipsism

    Science.gov (United States)

    Martínez-Delgado, Alberto

    2002-11-01

    This paper criticizes radical constructivism of the Glasersfeld type, pointing out some contradictions between the declared radical principles and their theoretical and practical development. These contradictions manifest themselves in a frequent oscillation between solipsism and realism, despite constructivist claims to be an anti-realist theory. The paper also points out the contradiction between the relativism of the radical constructivist principles and the constructivist exclusion of other epistemological or educational paradigms. It also disputes the originality and importance of the radical constructivist paradigm, suggesting the idea of an isomorphism between radical constructivist theory and contemplative realism. In addition, some pedagogical and scientific methodological aspects of the radical constructivist model are examined. Although radical constructivism claims to be a rational theory and advocates deductive thinking, it is argued that there is no logical deductive connection between the radical principles of constructivism and the radical constructivist ideas about scientific research and learning. The paper suggests the possibility of an ideological substratum in the construction and hegemonic success of subjective constructivism and, finally, briefly advances an alternative realist model to epistemological and educational radical constructivism.

  9. EPR spin trapping of protein radicals

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Hawkins, Clare Louise

    2004-01-01

    Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress...... and via enzymatic reactions. Over the last 15 years this technique has also found increasing use in detecting and identifying radicals formed on biological macromolecules as a result of either radical reactions or enzymatic processes. Though the EPR signals that result from the trapping of large, slowly...... tumbling radicals are often broad and relatively poor in distinctive features, a number of techniques have been developed that allow a wealth of information to be obtained about the nature, site, and reactions of such radicals. This article summarizes recent developments in this area and reviews selected...

  10. Radical Reactions and Its Synthetic Application

    Institute of Scientific and Technical Information of China (English)

    Takeaki Naito

    2005-01-01

    @@ 1Introduction Strategies involving radical reactions have become preeminent tools in organic synthesis. Free radical-mediated cyclization has developed as a powerful method for preparing various types of cyclic compounds via carbon-carbon bond-forming processes. In order to develop effective and convenient methods for the synthesis of biologically active cyclic amines, we have focused our efforts on radical reactions using aldehydes, ketones,and C-C multiple bonds as a radical precursor and/or an oxime ether, hydrazone, and nitrone as a radical acceptor. In this lecture, I would like to talk on radical addition-cyclization of oxime ether and its application to the synthesis of martinellines.

  11. Radicalization In Pakistan And The Spread Of Radical Islam In Pakistan

    Directory of Open Access Journals (Sweden)

    Bahir ahmad

    2015-08-01

    Full Text Available ABSTRACT It is pertinent to mention that radicalism is not intrinsic to Islam and radical interpretations of the religion or for that matter may occur within any way of life and religion Saikal 2003 and yet the question remains as to why Muslims in certain geographical regions have more radical approaches towards their religion and also that what are the causes of such radicalization. Becoming a radical Muslim is not even a matter of a day nor is it a sudden process. There are several reasons behind making a person radical peaceful angry smiling or tolerant. For knowing the reason behind radicalization or radicals persons one has to understand the causes. Tracing these causes is one of the ways to eliminate such behavior. The first step in the elimination of the radical sentiments in a person is to develop peace in his personality Fair Malhotra amp Shapiro 2010. The chapter which has been addressed here is going to shed light on the roots and symptoms of the radicalism. There will be a brief discussion on how the roots of radicalism can be traced and can be eliminated. The assessment and discussion will be conducted on the parameters of the economy media politics and theology from social cultural point of view. According to the analysis of Ahrari 2000 political factor is one of the major and direct factors which have resulted in causing of the radicalism. These factors however intertwine with one another. Radical actions cannot take place only because of the political factors.

  12. Serendipitous Findings While Researching Oxygen Free Radicals

    OpenAIRE

    Floyd, Robert A.

    2009-01-01

    This review is based on the honor of receiving the Discovery Award from the Society of Free Radical Biology and Medicine. The review is reflective and presents our thinking which led to experiments that yielded novel observations. Critical questioning of our understanding of oxygen free radicals in biomedical problems led us to use and develop more direct and extremely sensitive methods. This included nitrone free radical spin-trapping and HPLC-electrochemical detection. This technology led t...

  13. Bioinspired terpene synthesis: a radical approach.

    Science.gov (United States)

    Justicia, José; Álvarez de Cienfuegos, Luis; Campaña, Araceli G; Miguel, Delia; Jakoby, Verena; Gansäuer, Andreas; Cuerva, Juan M

    2011-07-01

    This tutorial review highlights the development of radical-based bioinspired synthesis of terpenes from the initial proposal to the development of modern catalytic methods for performing such processes. The power of the radical approach is demonstrated by the straightforward syntheses of many natural products from readily available starting materials. The efficiency of these processes nicely complements the described cationic polyolefin cyclisations and even suggests that modern radical methods provide means to improve upon nature's synthetic pathways.

  14. Superspecial radical%超特殊根

    Institute of Scientific and Technical Information of China (English)

    于淑兰

    2001-01-01

    定义了超特殊根,即由无零因子的绝对半素环类所确定的上根,并证明了它是一个特殊根。%The superspecial radical is defined, it is the upper radical, determined by the rings class consisted without divisors of zero and absolutely semiprings. And it is a special radical.

  15. Neurotoxins: Free Radical Mechanisms and Melatonin Protection

    OpenAIRE

    2010-01-01

    Toxins that pass through the blood-brain barrier put neurons and glia in peril. The damage inflicted is usually a consequence of the ability of these toxic agents to induce free radical generation within cells but especially at the level of the mitochondria. The elevated production of oxygen and nitrogen-based radicals and related non-radical products leads to the oxidation of essential macromolecules including lipids, proteins and DNA. The resultant damage is referred to as oxidative and nit...

  16. Radical-free biology of oxidative stress

    OpenAIRE

    2008-01-01

    Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the “redox hypothesis,” is that oxidative stress occurs as a consequence of disruption of thi...

  17. Photodynamically generated bovine serum albumin radicals

    DEFF Research Database (Denmark)

    Silvester, J A; Timmins, G S; Davies, Michael Jonathan

    1998-01-01

    Porphyrin-sensitized photoxidation of bovine serum albumin (BSA) results in oxidation of the protein at (at least) two different, specific sites: the Cys-34 residue giving rise to a thiyl radical (RS.); and one or both of the tryptophan residues (Trp-134 and Trp-214) resulting in the formation of...... of proteases. The generation of protein-derived radicals also results in an enhancement of photobleaching of the porphyrin, suggesting that protein radical generation is linked to porphyrin photooxidation....

  18. Formation of free radicals during phacoemulsification.

    Science.gov (United States)

    Holst, A; Rolfsen, W; Svensson, B; Ollinger, K; Lundgren, B

    1993-04-01

    During phacoemulsification cavitation bubbles are formed. These bubbles are believed to be one source of damage to corneal endothelium seen after phacoemulsification. Free radicals are induced whenever cavitation bubbles implode. The aim of this study was to confirm the initiation of free radicals by phacoemulsification and to correlate the power of ultrasound in the phacoemulsification process to the amount of free radicals formed, using both in vitro and in vivo techniques. The formation of free radicals was determined by adding luminol to a buffer and measuring the chemoluminescence in vitro and in rabbit eyes (Lumacounter 2080 or a single-photon-counting apparatus) during phacoemulsification. The data obtained show that free radicals are formed during phacoemulsification and that the amount of free radicals correlates with the power of ultrasound. Furthermore, the radical formation could be inhibited by the radical scavengers SOD, Healon and Healon GV. These results were achieved both in vitro in the test tube and in vivo in rabbit eyes. By showing that the addition of SOD to the irrigation buffer during phacoemulsification decreases the corneal endothelial cell damage, we show that free radicals could have a role in postoperative complications seen clinically.

  19. Near-Ring Radicals and Class Pairs

    Institute of Scientific and Technical Information of China (English)

    L.Godloza; N.J.Groenewald; W.A.Olivier

    2005-01-01

    For near-ring ideal mappings p1 and p2, we investigate radical theoretical properties of and the relationship among the class pairs (p1: p2), (Sp2: Sp1) and (Rp2:Rp1). Conditions on p1 and p2 are given for a general class pair to form a radical class of various types. These types include the Plotkin and KA-radical varieties. A number of examples are shown to motivate the suitability of the theory of Hoehnke-radicals over KA-radicals when radical pairs of near-rings are studied. In particular, it is shown that (pc: P3) forms a KA-radical class, where Pc denotes the class of completely prime nearrings and P3 the class of 3-prime near-rings. This gives another near-ring generalization of the 2-primal ring concept. The theory of radical pairs are also used to show that in general the class of 3-semiprime near-rings is not the semisimple class of the 3-prime radical.

  20. Benzyl isothiocyanate inhibits epithelial-mesenchymal transition in cultured and xenografted human breast cancer cells.

    Science.gov (United States)

    Sehrawat, Anuradha; Singh, Shivendra V

    2011-07-01

    We showed previously that cruciferous vegetable constituent benzyl isothiocyanate (BITC) inhibits growth of cultured and xenografted human breast cancer cells and suppresses mammary cancer development in a transgenic mouse model. We now show, for the first time, that BITC inhibits epithelial-mesenchymal transition (EMT) in human breast cancer cells. Exposure of estrogen-independent MDA-MB-231 and estrogen-responsive MCF-7 human breast cancer cell lines and a pancreatic cancer cell line (PL-45) to BITC resulted in upregulation of epithelial markers (e.g., E-cadherin and/or occludin) with a concomitant decrease in protein levels of mesenchymal markers, including vimentin, fibronectin, snail, and/or c-Met. The BITC-mediated induction of E-cadherin protein was accompanied by an increase in its transcription, whereas BITC-treated MDA-MB-231 cells exhibited suppression of vimentin, snail, and slug mRNA levels. Experimental EMT induced by exposure to TGFβ and TNFα or Rb knockdown in a spontaneously immortalized nontumorigenic human mammary epithelial cell line (MCF-10A) was also partially reversed by BITC treatment. The TGFβ-/TNFα-induced migration of MCF-10A cells was inhibited in the presence of BITC, which was partially attenuated by RNA interference of E-cadherin. Inhibition of MDA-MB-231 xenograft growth in vivo in female athymic mice by BITC administration was associated with an increase in protein level of E-cadherin and suppression of vimentin and fibronectin protein expression. In conclusion, this study reports a novel anticancer effect of BITC involving inhibition of EMT, a process triggered during progression of cancer to invasive state.

  1. Vasodilation effect of 2-benzyl-5-hydroxy-6-methoxy-3, 4-dihydroisoquinolin-1-one.

    Science.gov (United States)

    Xu, Wei-Qi; Xiong, Zhi-Zheng; Chen, Ting-Ting; Gao, Xiao-Yan; Yu, Hang; Zhang, San-Qi; Cao, Yong-Xiao

    2012-08-01

    A 2-Benzyl-5-hydroxy-6-methoxy-3, 4-dihydroisoquinolin-1-one (ZC2) is a newly synthesized isoquinolinone compound. Its effect on vasodilation was evaluated in the present study. Isometric tension of rat artery rings was recorded by a sensitive myography system in vitro. The results showed that ZC2 relaxed rat mesenteric arteries pre-contracted by KCl, phenylephrine and 9, 11- dideoxy- 11α, 9α-epoxymethano-prostaglandin F2α (U46619), and abdominal aorta pre-contracted by KCl in a concentration-dependent manner. The ZC2-induced vasodilation was not affected by an endothelium denudation. ZC2 rightwards shifted the concentration-contraction curves, induced by KCl, phenylephrine, and 5-hydroxytryptamine (5-HT) in a non-parallel manner, which suggests that the vasodilation effects are most likely via voltage-dependent calcium channel (VDCC) and receptor-operated calcium channel (ROCC). Moreover, in Ca(2+)-free medium, ZC2 concentration-dependently depressed the vasoconstrictions induced by phenylephrine and CaCl(2), and decreased a contractile response induced by caffeine, which indicates a role of extracellular Ca(2+) influx inhibition through VDCC and ROCC, and intracellular Ca(2+) release from Ca(2+) store via the ryanodine receptors. Glibenclamide did not affect the vasodilation induced by ZC2, suggesting that ATP sensitive potassium channel is not involved in the vasodilation. The results indicate that ZC2 induces vasodilation by inhibiting the VDCC and ROCC, and receptormediated Ca(2+) influx and release. The inhibition of intracellular Ca(2+) release may be mediated via the ryanodine receptors.

  2. Inhibition of human breast cancer xenograft growth by cruciferous vegetable constituent benzyl isothiocyanate.

    Science.gov (United States)

    Warin, Renaud; Xiao, Dong; Arlotti, Julie A; Bommareddy, Ajay; Singh, Shivendra V

    2010-05-01

    Benzyl isothiocyanate (BITC), a constituent of cruciferous vegetables such as garden cress, inhibits growth of human breast cancer cell lines in culture. The present study was undertaken to determine in vivo efficacy of BITC against MDA-MB-231 human breast cancer xenografts. The BITC administration retarded growth of MDA-MB-231 cells subcutaneously implanted in female nude mice without causing weight loss or any other side effects. The BITC-mediated suppression of MDA-MB-231 xenograft growth correlated with reduced cell proliferation as revealed by immunohistochemical analysis for Ki-67 expression. Analysis of the vasculature in the tumors from BITC-treated mice indicated smaller vessel area compared with control tumors based on immunohistochemistry for angiogenesis marker CD31. The BITC-mediated inhibition of angiogenesis in vivo correlated with downregulation of vascular endothelial growth factor (VEGF) receptor 2 protein levels in the tumor. Consistent with these results, BITC treatment suppressed VEGF secretion and VEGF receptor 2 protein levels in cultured MDA-MB-231 cells. Moreover, the BITC-treated MDA-MB-231 cells exhibited reduced capacity for migration compared with vehicle-treated control cells. In contrast to cellular data, BITC administration failed to elicit apoptotic response as judged by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. In conclusion, the present study demonstrates in vivo anti-cancer efficacy of BITC against MDA-MB-231 xenografts in association with reduced cell proliferation and suppression of neovascularization. These preclinical observations merit clinical investigation to determine efficacy of BITC against human breast cancers.

  3. Inhibitory effects of chitosan on superoxide anion radicals and lipid free radicals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the electron spin resonance (ESR) technique, the inhibitory effects of chitosan on superoxide anion radicals and linoleic acid lipid radicals were found. The inhibitory ratio E for these two kinds of radicals is in proportion to the concentration of chitosan. It was also observed that E for linoleic acid lipid radicals increased with the increase of the degree of deacetylation and decreased with the increase of the molecular weight of chitosan.

  4. CeO2-modified Au@SBA-15 nanocatalysts for liquid-phase selective oxidation of benzyl alcohol

    Science.gov (United States)

    Wang, Tuo; Yuan, Xiang; Li, Shuirong; Zeng, Liang; Gong, Jinlong

    2015-04-01

    Tuning the interfacial perimeter and structure is crucial to understanding the origin of catalytic performance. This paper describes the design, characterization, and application of CeO2 modified Au@SBA-15 (Au-CeO2@SBA-15) catalysts in selective oxidation of benzyl alcohol. The reaction results showed that Au-CeO2@SBA-15 catalysts exhibited higher catalytic activity compared with Au@SBA-15 and Au/CeO2 catalysts under identical conditions along with the high selectivity towards benzaldehyde (>99%). The turnover frequency of benzyl alcohol over the Au-100CeO2@SBA-15 catalyst is about nine-fold and four-fold higher than those of Au@SBA-15 and Au/CeO2 catalysts, respectively. The supported catalysts were characterized by N2 adsorption-desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, scanning transmission electron microscopy-energy dispersive spectrometry, and X-ray photoelectron spectroscopy. It was found that the Au and small CeO2 nanoparticles (~5 nm) were homogeneously mixed in the channels of SBA-15, which led to an increase in the interfacial area between Au and CeO2 and consequently a better catalytic performance of Au-CeO2@SBA-15 catalysts for the selective oxidation of benzyl alcohol to benzaldehyde compared with that of Au/CeO2. The prevention of agglomeration and leaching of Au nanoparticles by restricting them inside the mesopores of SBA-15 was conducive to the stable existence of large quantities of Au-CeO2 interface, which leads to high stability of the Au-CeO2@SBA-15 catalyst.Tuning the interfacial perimeter and structure is crucial to understanding the origin of catalytic performance. This paper describes the design, characterization, and application of CeO2 modified Au@SBA-15 (Au-CeO2@SBA-15) catalysts in selective oxidation of benzyl alcohol. The reaction results showed that Au-CeO2@SBA-15 catalysts

  5. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-08-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of narrow mental states; that is, the idea that the mental content of an individual can be fully characterised without any reference external to her or him. I show that this fact imposes some severe restrictions to SIS to be incorporated into RC. In particular, I argue that only qualitative studies can comply with the requirement of narrowness. Nevertheless, I propose that quantitative works can be employed as sources of types in order to study token actual students. I use this type-token dichotomy to put forward an outline of a theory of the relation between school contents and mental contents. In this view, token mental contents regarding a given topic can be defined, and probed, only by resorting to typical school contents.

  6. Iron and iron derived radicals

    Energy Technology Data Exchange (ETDEWEB)

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

  7. Photoionisation of the tropyl radical

    Directory of Open Access Journals (Sweden)

    Kathrin H. Fischer

    2013-04-01

    Full Text Available We present a study on the photoionisation of the cycloheptatrienyl (tropyl radical, C7H7, using tunable vacuum ultraviolet synchrotron radiation. Tropyl is generated by flash pyrolysis from bitropyl. Ions and electrons are detected in coincidence, permitting us to record mass-selected photoelectron spectra. The threshold photoelectron spectrum of tropyl, corresponding to the X+ 1A1’ ← X 2E2” transition, reveals an ionisation energy of 6.23 ± 0.02 eV, in good agreement with Rydberg extrapolations, but slightly lower than the value derived from earlier photoelectron spectra. Several vibrations can be resolved and are reassigned to the C–C stretch mode ν16+ and to a combination of ν16+ with the ring breathing mode ν2+. Above 10.55 eV dissociative photoionisation of tropyl is observed, leading to the formation of C5H5+ and C2H2.

  8. CeO2-modified Au@SBA-15 nanocatalysts for liquid-phase selective oxidation of benzyl alcohol.

    Science.gov (United States)

    Wang, Tuo; Yuan, Xiang; Li, Shuirong; Zeng, Liang; Gong, Jinlong

    2015-05-07

    Tuning the interfacial perimeter and structure is crucial to understanding the origin of catalytic performance. This paper describes the design, characterization, and application of CeO2 modified Au@SBA-15 (Au-CeO2@SBA-15) catalysts in selective oxidation of benzyl alcohol. The reaction results showed that Au-CeO2@SBA-15 catalysts exhibited higher catalytic activity compared with Au@SBA-15 and Au/CeO2 catalysts under identical conditions along with the high selectivity towards benzaldehyde (>99%). The turnover frequency of benzyl alcohol over the Au-100CeO2@SBA-15 catalyst is about nine-fold and four-fold higher than those of Au@SBA-15 and Au/CeO2 catalysts, respectively. The supported catalysts were characterized by N2 adsorption-desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, scanning transmission electron microscopy-energy dispersive spectrometry, and X-ray photoelectron spectroscopy. It was found that the Au and small CeO2 nanoparticles (∼5 nm) were homogeneously mixed in the channels of SBA-15, which led to an increase in the interfacial area between Au and CeO2 and consequently a better catalytic performance of Au-CeO2@SBA-15 catalysts for the selective oxidation of benzyl alcohol to benzaldehyde compared with that of Au/CeO2. The prevention of agglomeration and leaching of Au nanoparticles by restricting them inside the mesopores of SBA-15 was conducive to the stable existence of large quantities of Au-CeO2 interface, which leads to high stability of the Au-CeO2@SBA-15 catalyst.

  9. Hydrolytic metabolism of phenyl and benzyl salicylates, fragrances and flavoring agents in foods, by microsomes of rat and human tissues.

    Science.gov (United States)

    Ozaki, Hitomi; Sugihara, Kazumi; Tamura, Yuki; Fujino, Chieri; Watanabe, Yoko; Uramaru, Naoto; Sone, Tomomichi; Ohta, Shigeru; Kitamura, Shigeyuki

    2015-12-01

    Salicylates are used as fragrance and flavor ingredients for foods, as UV absorbers and as medicines. Here, we examined the hydrolytic metabolism of phenyl and benzyl salicylates by various tissue microsomes and plasma of rats, and by human liver and small-intestinal microsomes. Both salicylates were readily hydrolyzed by tissue microsomes, predominantly in small intestine, followed by liver, although phenyl salicylate was much more rapidly hydrolyzed than benzyl salicylate. The liver and small-intestinal microsomal hydrolase activities were completely inhibited by bis(4-nitrophenyl)phosphate, and could be extracted with Triton X-100. Phenyl salicylate-hydrolyzing activity was co-eluted with carboxylesterase activity by anion exchange column chromatography of the Triton X-100 extracts of liver and small-intestinal microsomes. Expression of rat liver and small-intestinal isoforms of carboxylesterase, Ces1e and Ces2c (AB010632), in COS cells resulted in significant phenyl salicylate-hydrolyzing activities with the same specific activities as those of liver and small-intestinal microsomes, respectively. Human small-intestinal microsomes also exhibited higher hydrolyzing activity than liver microsomes towards these salicylates. Human CES1 and CES2 isozymes expressed in COS cells both readily hydrolyzed phenyl salicylate, but the activity of CES2 was higher than that of CES1. These results indicate that significant amounts of salicylic acid might be formed by microsomal hydrolysis of phenyl and benzyl salicylates in vivo. The possible pharmacological and toxicological effects of salicylic acid released from salicylates present in commercial products should be considered.

  10. Hydroxyl radical reaction with trans-resveratrol: initial carbon radical adduct formation followed by rearrangement to phenoxyl radical.

    Science.gov (United States)

    Li, Dan-Dan; Han, Rui-Min; Liang, Ran; Chen, Chang-Hui; Lai, Wenzhen; Zhang, Jian-Ping; Skibsted, Leif H

    2012-06-21

    In the reaction between trans-resveratrol (resveratrol) and the hydroxyl radical, kinetic product control leads to a short-lived hydroxyl radical adduct with an absorption maximum at 420 nm and a lifetime of 0.21 ± 0.01 μs (anaerobic acetonitrile at 25 °C) as shown by laser flash photolysis using N-hydroxypyridine-2(1H)-thione (N-HPT) as a "photo-Fenton" reagent. The transient spectra of the radical adduct are in agreement with density functional theory (DFT) calculations showing an absorption maximum at 442 or 422 nm for C2 and C6 hydroxyl adducts, respectively, and showing the lowest energy for the transition state leading to the C2 adduct compared to other radical products. From this initial product, the relative long-lived 4'-phenoxyl radical of resveratrol (τ = 9.9 ± 0.9 μs) with an absorption maximum at 390 nm is formed in a process with a time constant (τ = 0.21 ± 0.01 μs) similar to the decay constant for the C2 hydroxyl adduct (or a C2/C6 hydroxyl adduct mixture) and in agreement with thermodynamics identifying this product as the most stable resveratrol radical. The hydroxyl radical adduct to phenoxyl radical conversion with concomitant water dissociation has a rate constant of 5 × 10(6) s(-1) and may occur by intramolecular hydrogen atom transfer or by stepwise proton-assisted electron transfer. Photolysis of N-HPT also leads to a thiyl radical which adds to resveratrol in a parallel reaction forming a sulfur radical adduct with a lifetime of 0.28 ± 0.04 μs and an absorption maximum at 483 nm.

  11. Ivermectin versus benzyl benzoate applied once or twice to treat human scabies in Dakar, Senegal : a randomized controlled trial

    OpenAIRE

    Ly, Fatimata; Caumes, Eric; Ndaw, Cheick Ahmet Tidiane; Ndiaye, Bassirou; Mahé, Antoine

    2009-01-01

    Objective To compare the effectiveness of oral ivermectin (IV) and two different modalities of topical benzyl benzoate (BB) for treating scabies in a community setting. Methods The trial included patients aged 5-65 years with scabies who attended the dermatology department at the Institut d'Hygiene Sociale in Dakar, Senegal. The randomized, open trial considered three treatments: a single application of 12.5% BB over 24 hours (BB1. group), two applications of BB, each over 24 hours (BB2 group...

  12. Anchoring Tri(8-QuinolinolatoIron Onto Sba-15 for Partial Oxidation of Benzyl Alcohol Using Water as the Solvent

    Directory of Open Access Journals (Sweden)

    Yang Xiaoyuan

    2014-09-01

    Full Text Available Tri(8-quinolinolatoiron complex immobilized onto SBA-15 catalyst has been synthesized through a stepwise procedure. The characterization results indicated that the BET surface area, total pore volume and average pore width decrease after stepwise modification of SBA-15, while the structure keeps intact. Catalytic tests showed that FeQ3-SBA-15 catalyzes the oxidation reaction well with 34.8% conversion of benzyl alcohol and 74.7% selectivity to benzaldehyde when water is used as the solvent after 1 h reaction. In addition, homogeneous catalyst tri(8-quinolinolatoiron exhibits very bad catalytic behavior using water as the solvent.

  13. Thermodynamic, adsorption and corrosion inhibitive behaviour of benzyl nicotinate on cold rolled steel in sulphuric acid solution

    Directory of Open Access Journals (Sweden)

    Vinutha Rangaswamy Mutugadahalli

    2015-12-01

    Full Text Available The inhibition performance of benzyl nicotinate (BN on corrosion of cold rolled steel (CRS in 0.5 M H2SO4 solution has been investigated using weight loss, Tafel polarization and electrochemical impedance spectroscopy (EIS. The BN acts as mixed type inhibitor. The thermodynamic parameters indicate the comprehensive nature adsorption of BN on CRS which obey Langmuir isotherm. Morphological investigation of corrosion inhibition is carried out using AFM and optical microscopic studies support the formation of inhibitor film on CRS. There is a good agreement between the values of weight loss measurements and electrochemical studies. 

  14. Benzyl-1,2,4-triazoles as CB1 Cannabinoid Receptor Ligands: Preparation and In Vitro Pharmacological Evaluation

    Science.gov (United States)

    Hernandez-Folgado, Laura; Decara, Juan; Rodríguez de Fonseca, Fernando; Goya, Pilar; Jagerovic, Nadine

    2016-01-01

    In a previous study, we have identified 3-alkyl-1,5-diaryl-1H-1,2,4-triazoles to be a novel class of cannabinoid type 1 receptor (CB1R) antagonists. In order to expand the number of cannabinoid ligands with a central 1,2,4-triazole scaffold, we have synthesized a novel series of 1-benzyl-1H-1,2,4-triazoles, and some of them were evaluated by CB1R radioligand binding assays. Compound 12a showed the most interesting pharmacological properties, possessing a CB1R affinity in the nanomolar range. PMID:27127651

  15. Radical Behaviorism and Buddhism: Complementarities and Conflicts

    Science.gov (United States)

    Diller, James W.; Lattal, Kennon A.

    2008-01-01

    Comparisons have been made between Buddhism and the philosophy of science in general, but there have been only a few attempts to draw comparisons directly with the philosophy of radical behaviorism. The present review therefore considers heretofore unconsidered points of comparison between Buddhism and radical behaviorism in terms of their…

  16. Resonance raman studies of phenylcyclopropane radical cations

    NARCIS (Netherlands)

    Godbout, J.T.; Zuilhof, H.; Heim, G.; Gould, I.R.; Goodman, J.L.; Dinnocenzo, J.P.; Myers Kelley, A.

    2000-01-01

    Resonance Raman spectra of the radical cations of phenylcyclopropane and trans-1-phenyl-2-methylcyclopropane are reported. A near-UV pump pulse excites a photosensitizer which oxidizes the species of interest, and a visible probe pulse delayed by 35 ns obtains the spectrum of the radical ion. The tr

  17. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.

    2011-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.

  18. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.

    2013-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.

  19. Organic chemistry: A radical step forward

    Science.gov (United States)

    Zhang, Wenhao; Li, Ang

    2017-02-01

    Free radicals are notorious for unselective coupling reactions; however, the coupling of free radicals generated from acyl tellurides has now been shown to form C-C bonds with remarkable fidelity, which enables easy one-step assembly of densely oxygenated natural product motifs.

  20. Radical-Local Teaching and Learning

    DEFF Research Database (Denmark)

    Hedegaard, Mariane; Chaiklin, Seth

    radical-local teaching and learning approach. The first half of the book introduces the idea of radical-local teaching and learning and develops the theoretical background for this perspective, drawing on the cultural-historical research tradition, particularly from Vygotsky, El'konin, Davydov...

  1. Victimology: A Consideration of the Radical Critique.

    Science.gov (United States)

    Friedrichs, David O.

    1983-01-01

    Discusses the emergence of a new radical model in criminology and a new subdisciplinary area of concern, victimology, with roots in Marx and Engels' original formulations. Argues that the radical understanding of victimization provides an important corrective to mainstream approaches and broadens the focus of the concept of victimization. (JAC)

  2. Localization versus delocalization in diamine radical cations

    DEFF Research Database (Denmark)

    Brouwer, A.M.; Wiering, P.G.; Zwier, J.M.;

    1997-01-01

    The optical absorption spectrum of the radical cation of 1,4-diphenylpiperazine 2a shows a strong transition in the near-IR, and only a weak band at 445 nm, in the region where aniline radical cations normally absorb strongly. This indicates that the charge and spin are delocalized over the two...

  3. Free Radical Mechanisms in Autoxidation Processes.

    Science.gov (United States)

    Simic, Michael G.

    1981-01-01

    Discusses the use of steady-state radiation chemistry and pulse radiolysis for the generation of initial free radicals and formation of peroxy radicals in the autoxidation process. Provides information regarding the autoxidation process. Defines autoxidation reactions and antioxidant action. (CS)

  4. Coenzyme B12 model studies: Equilibrium constants for the H-dependent axial ligation of benzyl(aquo)cobaloxime by various N- and S-donor ligands

    Indian Academy of Sciences (India)

    D Sudarshan Reddy; N Ravi Kumar Reddy; V Sridhar; S Satyanarayana

    2002-02-01

    Equilibria of the axial ligation of benzyl(aquo)cobaloximes by imidazole, 1-methyl imidazole, histidine, histamine, glycine, ethyl glycine ester, thiourea and urea have been spectrophotometrically measured in aqueous solutions of ionic strength 1.0 M (KCl) at 25°C as a function of H. The equilibrium constants are in the order CN- > 1-methyl imidazole > imidazole > histidine > histamine > glycine > ethyl glycine ester > thiourea > urea. The order of stability of benzyl(ligand)cobaloxime is explained based on the basicity of the ligand, Co(III) → - back bonding and soft-soft and soft-hard interaction. Imidazole, substituted imidazoles, histidine and histamine form more stable complexes than glycine, ethyl glycine ester in contrast to the basicity of the ligands. Benzyl(ligand)cobaloximes were isolated and characterized by elemental analysis, IR and 1H NMR spectra.

  5. (4Z-1-Benzyl-4-(2-oxopropylidene-2,3,4,5-tetrahydro-1H-1,5-benzodiazepin-2-one

    Directory of Open Access Journals (Sweden)

    Mohamed Samba

    2016-09-01

    Full Text Available The title compound, C19H18N2O2, crystallizes with two independent molecules in the asymmetric unit which differ in conformation. The seven-membered ring adopts a `bowl' conformation with the benzyl group oriented away from the open face in one molecule, while the benzyl group is oriented towards the open face in the other. The benzyl group of one independent molecule is disordered over two sets of sites with refined site-occupancy factors of 0.454 (8 and 0.546 (8. The two molecules are linked via C—H...O hydrogen bonds and centrosymmetrically related pairs of molecules form dimers through C—H...O hydrogen bonds, packing in rows parallel to the c axis.

  6. Place of Schauta's radical vaginal hysterectomy.

    Science.gov (United States)

    Roy, Michel; Plante, Marie

    2011-04-01

    Women affected by early stage invasive cancer of the cervix are usually treated by surgery. Radical abdominal hysterectomy with pelvic lymphadenectomy is the most widely used technique. Because the morbidity of the abdominal approach can be important, the radical vaginal hysterectomy has gained acceptance in gynaecologic oncology. New instrumentation in laparoscopy also opens the possibility of treating cervical cancer by laparoscopically assisted vaginal radical hysterectomy and also total laparoscopic radical hysterectomy. Before these techniques become widely accepted, it has to be shown that safety and efficacy are comparable with the 'standard' abdominal approach. In this chapter, we review the technique of radical vaginal hysterectomy with pelvic lymphadenectomy and evaluate results of published studies, comparing the abdominal, vaginal and laparoscopic approaches.

  7. Crystal structures of the even and odd bolaform amino acid derivatives (11-N-[benzyloxycarbonyl-L-alanyl]aminoundecanoyl)-L-alanyl benzyl ester and (12-N-[benzyloxycarbonyl-L-alanyl]aminododecanoyl)-L-alanyl benzyl ester.

    Science.gov (United States)

    Schade, B; Hubert, V; André, C; Luger, P; Fuhrhop, J H

    1997-04-01

    Reaction of two alpha, omega-aminocarboxylic acids with N- and C-protected alanine leads to bolaform compounds with two secondary amide groups on one end and one such group at the other end. Unsymmetric sheet-like structures are formed in the crystals. (11-N-[Benzyloxycarbonyl-L-alanyl] aminoundecanoyl)-L-alanyl benzyl ester (1) and (12-N-[benzyloxycarbonyl-L-alanyl] aminododecanoyl)-L-alanyl benzyl ester (2) form triclinic crystals (spacegroup P1, No.1) with a = 4.917, b = 5.614, c = 29.02 A. alpha = 88.40, beta = 93.50, gamma = 100.21 degrees, Z = 1 (1) and a = 4.954, b = 5.613, c = 30.23 A, alpha = 93.44, beta = 90.07, gamma = 104.15 degrees, Z = 1 (2). The crystal structures were solved via direct methods and refined to R = 0.040 (1) and 0.078 (2) from 2441 and 2725 reflections.

  8. 1, 3-Dipolar cycloaddition reactions: Synthesis of 5-benzyl-1-(2',4'-dibromophenyl)-3-(4"-substituted phenyl)-3a,4,6,6a-tetrahydro-1, 5-pyrrolo[3,4-]pyrazole-4,6-dione derivatives

    Indian Academy of Sciences (India)

    Manpreet Kaur; Baldev Singh; Baljit Singh

    2013-11-01

    1,3-Dipolar cycloaddition of nitrilimines 3 with -benzyl maleimide 4 has provided 5-benzyl-1-(2',4'-dibromophenyl)-3-(4"-substituted phenyl)-3a,4,6,6a-tetrahydro-1,5-pyrrolo[3,4-]pyrazole-4,6-dione derivatives 5 in excellent yield as the only isomer through a concerted pathway.

  9. HYDROPHILIC MODIFICATION OF PPESK POROUS MEMBRANES VIA AQUEOUS SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhuan Yi; You-yi Xu; Li-ping Zhu; Han-bang Dong; Bao-ku Zhu

    2009-01-01

    Hydrophilic surface modification of poly(phthalazinone ether sulfone ketone)(PPESK)porous membranes was achieved via surface-initiated atom transfer radical polymerization(ATRP)in aqueous medium.Prior to ATRP,chloromethyl groups were introduced onto PPESK main chains by chloromethylation.Chloromethylated PPESK(CMPPESK)was fabricated into porous membrane through phase inversion technique.Hydrophilic poly(poly(ethylene glycol)methyl ether methacrylate)(P(PEGMA))brushes were grafted from CMPPESK membrane under the initiation of benzyl chloride groups on membrane surface.The results of Fourier transform infrared(FT-IR)spectroscopy and X-ray photoelectron spectroscopy (XPS)confirmed the grafting of P(PEGMA)chains.Water contact angle measurements and protein adsorption experiments suggested that the hydrophilicity and anti-fouling ability of PPESK membrane were remarkably improved after the grafting of P(PEGMA)brushes.The addition of small amount of water in the reaction solvent apparently accelerated the progress of the grafting reaction.The use of CuCl2 in the catalyst system promoted the controllability of the ATRP reaction.

  10. Changes in acaricidal potency by introducing functional radicals and an acaricidal constituent isolated from Schizonepeta tenuifolia.

    Science.gov (United States)

    Yang, Ji-Yeon; Lee, Hoi-Seon

    2013-11-27

    The acaricidal potential of an active constituent isolated from Schizonepeta tenuifolia oil and its structurally related derivatives was evaluated using filter paper and impregnated cotton fabric disk bioassays against house dust and stored food mites. The acaricidal constituent of S. tenuifolia oil was isolated by chromatographic techniques and identified as 2-isopropyl-5-methylcyclohexanone by GC-MS, (1)H-, and (13)C NMR spectra. 2-Isopropyl-5-methylcyclohexanone was a potent acaricide against house dust and stored food mites, based on the LD50 values from the filter paper and impregnated cotton fabric disk bioassays, followed by 4-isopropylcyclohexanone, 2-isopropylidene-5-methylcyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, and benzyl benzoate. Furthermore, 4-isopropylcyclohexanone and 2-isopropyl-5-methylcyclohexanone, which were introduced on the isopropyl (C3H7) functional radical of the cyclohexanone skeleton, had the highest acaricidal potency. These results indicate that S. tenuifolia oil and 2-isopropyl-5-methylcyclohexanone structural analogues could be effective natural acaricides for managing house dust and stored food mites.

  11. Two New Saccharide Fatty Acid Esters from the Fruit of Morinda citrifolia L. and Their ABTS Radical Scavenging Activities

    Directory of Open Access Journals (Sweden)

    Hong-Cai Zhang

    2014-01-01

    Full Text Available Two n ew saccharide fatty acid esters (1 and (2, and six other compounds were isolated from the fruit of Morinda citrifolia L. (Rubiaceae The structures were established as (2E-oct-2-enoate-2-O-β-D - glucopyranosyl-β-D-glucopyranoside(1, (2E-2,6-dimethyl -6-hydroxyl-oct-2,7-dienoate-2-O-β-D-glucopyranosyl-β-D-glucopyranoside(2, saccharumoside C(3, O-β-D-apiofuranosyl-(1→6-O-β-D-glucopyranosides of 3-methyl-2-butenol(4, 3-methyl-but-2-en-1-yl β-D-glucopyranosyl (1→6-β-D-glucopyranoside(5, benzyl - glucopyranoside(6, Hexyl-O-β-D-glucopyranoside(7, and caproic acid(8. Compound 1 and 2 showed moderate activity against ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonate radical in concentration of 0.1-3.2 mg/mL. Morinda citrifolia L., saccharide fatty acid ester, ABTS radical scavenging activity

  12. Pilot study of radical hysterectomy versus radical trachelectomy on sexual distress.

    Science.gov (United States)

    Brotto, Lori A; Smith, Kelly B; Breckon, Erin; Plante, Marie

    2013-01-01

    Radical trachelectomy, which leaves the uterus intact, has emerged as a desirable surgical option for eligible women with early-stage cervical cancer who wish to preserve fertility. The available data suggest excellent obstetrical outcomes with radical trachelectomy, and no differences in sexual responding between radical trachelectomy and radical hysterectomy. There is a need to examine the effect of radical hysterectomy on sexual distress given that it is distinct from sexual function. Participants were 34 women diagnosed with early-stage cervical cancer. The authors report 1-month postsurgery data for 29 women (radical hysterectomy group: n = 17, M age = 41.8 years; radical trachelectomy group: n = 12, M age = 31.8 years), and 6-month follow-up data on 26 women. Whereas both groups experienced an increase in sex-related distress immediately after surgery, distress continued to increase 6 months after surgery for the radical hysterectomy group but decreased in the radical trachelectomy group. There were no between-group differences in mood, anxiety, or general measures of health. The decrease in sex-related distress in the radical trachelectomy but not in the radical hysterectomy group suggests that the preservation of fertility may have attenuated sex-related distress. Care providers should counsel women exploring surgical options for cervical cancer about potential sex distress-related sequelae.

  13. A Novel Strategy Towards the Asymmetric Synthesis of Orthogonally Funtionalised 2-N-Benzyl-N-α-methylbenzylamino- 5-carboxymethyl-cyclopentane-1-carboxylic acid.

    Directory of Open Access Journals (Sweden)

    Julio G. Urones

    2004-04-01

    Full Text Available The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-α-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-α-methylbenzylamino-5–carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E-octa-2,6- diendioate with lithium N-α-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid is reported.

  14. s-Block organometallics: analysis of ion-association and noncovalent interactions on structure and function in benzyl-based compounds.

    Science.gov (United States)

    Torvisco, Ana; Ruhlandt-Senge, Karin

    2011-12-19

    The organometallic chemistry of alkali and alkaline-earth metals has been marred by synthetic setbacks because of their high reactivity. Advances in their synthesis and a better understanding of the stabilization effects of ligands and coligands have resulted in the revolution of s-block organometallics. Among those, benzyl-based derivatives have played a key role in developing this chemistry because factors such as the ligand size, charge delocalization, and introduction of electronic parameters along with metal effects can be analyzed. This article will focus on s-block benzylates and di- and triphenylmethanide derivatives with specific emphasis on the factors that stabilize the highly reactive metal species.

  15. Benzyl-penicillin (Penicillin G) transformation in aqueous solution at low temperature under controlled laboratory conditions.

    Science.gov (United States)

    Bergheim, Marlies; Helland, Tone; Kallenborn, Roland; Kümmerer, Klaus

    2010-12-01

    Antibiotics are released into the environment in a variety of ways: via wastewater effluent as a result of incomplete metabolism in the body after use in human therapy, as runoff after use in agriculture, through improper disposal by private households or hospitals or through insufficient removal by water treatment plants. Unlike in most European countries, in Arctic regions effluents are not suitably treated prior to their release into the aquatic environment. Also, many of the scattered human settlements in remote regions of the Arctic do not possess sewage treatment facilities and pharmaceutical residues therefore enter the aqueous environment untreated. Only limited data are available on the biodegradation of antibiotics under Arctic conditions. However, such information is needed to estimate the potential harm of antibiotics for the environment. Pen-G is used in this study since it is a widely prescribed antibiotic compound whose environmental properties have not yet been investigated in detail. Thus, for a very first assessment, the OECD approved biodegradation Zahn-Wellens test (ZWT, OECD 302 B) was used to study biodegradation and non-biotic elimination of the antibiotic Benzyl-penicillin (Pen-G) at different temperatures (5°C, 12.5°C and 20°C). The testing period was extended from the OECD standard of 28-42d. In addition to dissolved organic carbon (DOC), Pen-G levels and major transformation products were recorded continuously by LC-ion-trap-MS/MS. DOC monitoring revealed considerable temperature dependence for the degradation process of Pen-G. DOC loss was slowest at 5°C and considerably faster at 12.5°C and 20°C. In the initial step of degradation it was found that Pen-G was hydrolyzed. This hydrolyzed Pen-G was subsequently further degraded by decarboxylation, the result of which was 2-(5,5-dimethyl-1,3-thiazolidin-2-yl)-2-(2-phenylacetamido)acetic acid. Furthermore, direct elimination of 2-phenyl-acetaldehyde from the hydrolyzed and

  16. A novel serotonin transporter ligand: (5-Iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Z.-P.; Choi, S.-R.; Hou, Catherine; Mu Mu; Kung, M.-P. E-mail: kunghf@sunmac.spect.upenn.edu; Acton, Paul D.; Kung, Hank F

    2000-02-01

    The serotonin transporters (SERT) are the primary binding sites for selective serotonin reuptake inhibitors, commonly used antidepressants such as fluoxetine, sertraline, and paroxetine. Imaging of SERT with positron emission tomography and single photon emission computed tomography in humans would provide a useful tool for understanding how alterations of this system are related to depressive illnesses and other psychiatric disorders. In this article the synthesis and characterization of [{sup 125}I]ODAM [(5-iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol, 9)] as an imaging agent in the evaluation of central nervous system SERT are reported. A new reaction scheme was developed for the preparation of compound 9, ODAM, and the corresponding tri-n-butyltin derivative 10. Upon reacting 10 with hydrogen peroxide and sodium[{sup 125}I]iodide, the radiolabeled [{sup 125}I]9 was obtained in good yield (94% yield, radiochemical purity >95%). In an initial binding study using cortical membrane homogenates of rat brain, ODAM displayed a good binding affinity with a value of K{sub i}=2.8{+-}0.88 nM. Using LLC-PK{sub 1} cells specifically expressing the individual transporter (i.e. dopamine [DAT], norepinephrine [NET], and SERT, respectively), ODAM showed a strong inhibition on SERT (K{sub i}=0.12{+-}0.02 nM). Inhibition constants for the other two transporters were lower (K{sub i}=3.9{+-}0.7 {mu}M and 20.0 {+-} 1.9 nM for DAT and NET, respectively). Initial biodistribution study in rats after an intravenous (IV) injection of [{sup 125}I]ODAM showed a rapid brain uptake and washout (2.03, 1.49, 0.79, 0.27, and 0.07% dose/organ at 2, 30, 60, 120, and 240 min, respectively). The hypothalamus region where the serotonin neurons are located exhibited a high specific uptake. Ratios of hypothalamus-cerebellum/cerebellum based on percent dose per gram of these two regions showed values of 0.35, 0.86, 0.86, 0.63, and 0.34 at 2, 30, 60, 120, and 240 min, post-IV injection

  17. Benzyl isothiocyanate causes FoxO1-mediated autophagic death in human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Dong Xiao

    Full Text Available Benzyl isothiocyanate (BITC, a constituent of edible cruciferous vegetables, inhibits growth of breast cancer cells but the mechanisms underlying growth inhibitory effect of BITC are not fully understood. Here, we demonstrate that BITC treatment causes FoxO1-mediated autophagic death in cultured human breast cancer cells. The BITC-treated breast cancer cells (MDA-MB-231, MCF-7, MDA-MB-468, BT-474, and BRI-JM04 and MDA-MB-231 xenografts from BITC-treated mice exhibited several features characteristic of autophagy, including appearance of double-membrane vacuoles (transmission electron microscopy and acidic vesicular organelles (acridine orange staining, cleavage of microtubule-associated protein 1 light chain 3 (LC3, and/or suppression of p62 (p62/SQSTM1 or sequestosome 1 expression. On the other hand, a normal human mammary epithelial cell line (MCF-10A was resistant to BITC-induced autophagy. BITC-mediated inhibition of MDA-MB-231 and MCF-7 cell viability was partially but statistically significantly attenuated in the presence of autophagy inhibitors 3-methyl adenine and bafilomycin A1. Stable overexpression of Mn-superoxide dismutase, which was fully protective against apoptosis, conferred only partial protection against BITC-induced autophagy. BITC treatment decreased phosphorylation of mTOR and its downstream targets (P70s6k and 4E-BP1 in cultured MDA-MB-231 and MCF-7 cells and MDA-MB-231 xenografts, but activation of mTOR by transient overexpression of its positive regulator Rheb failed to confer protection against BITC-induced autophagy. Autophagy induction by BITC was associated with increased expression and acetylation of FoxO1. Furthermore, autophagy induction and cell growth inhibition resulting from BITC exposure were significantly attenuated by small interfering RNA knockdown of FoxO1. In conclusion, the present study provides novel insights into the molecular circuitry of BITC-induced cell death involving FoxO1-mediated autophagy.

  18. Reações de carbociclização radicalar de orto-iodoaliloxibenzoatos derivados de d-glicose e d-galactose e comparação com as reações de seus análogos benzamidas Radical carbocyclization reactions of ortho-iodoallyloxybenzoate derivatives of d-glucose and d-galactose and comparison with the reactions of their benzamide analogs

    Directory of Open Access Journals (Sweden)

    Ildefonso Binatti

    2005-12-01

    Full Text Available Two ortho-iodoallyloxybenzoates, methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl- alpha-D-glucopyranoside (3 and methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl- alpha-D-galactopyranoside (4 were synthesized in seven conventional steps from methyl alpha-D-glucopyranoside and methyl alpha-D-galactopyranoside, respectively. Bu3SnH-mediated aryl radical cyclization of 3 provided exclusively the hydrogenolysis product 12. The reaction of 4 gave the reduced uncyclized product 13 and only traces of 4A, resulting from 11-endo aryl radical cyclization. In previous papers we described that in similar Bu3SnH-mediated radical reaction of ortho-iodoallyloxybenzamides, analogs of 3 and 4, we obtained macrolactams resulting from 11-endo cyclization. An hypothesis to explain the differences is presented. It was assumed that in the aryl radical formed from iodobenzamides there is a suitable conformation to cyclization, which is stabilized by an intramolecular hydrogen bond.

  19. Selective Aerobic Oxidation of Benzyl Alcohol Driven by Visible Light on Gold Nanoparticles Supported on Hydrotalcite Modified by Nickel Ion

    Directory of Open Access Journals (Sweden)

    Dapeng Guo

    2016-04-01

    Full Text Available A series of hydrotalcite (HT and hydrotalcite modified by the transition metal ion Ni(II was prepared with a modified coprecipitation method before being loaded with gold nanoparticles. The gold supported on Ni3Al hydrotalcite with a Ni2+/Al3+ molar ratio of 3:1 was investigated. Different techniques such as X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and UV-vis diffuse reflection spectrum (UV-vis DRS were applied to characterize the catalysts. A single-phase catalyst with high crystallinity, a layered structure and good composition was successfully fabricated. Good conversions and superior selectivities in the oxidation of benzyl alcohol and its derivatives were obtained with visible light due to the effect of localized surface plasmon resonance (LSPR of gold nanoparticles and the synergy of the transition metal ion Ni(II. This reaction was proven to be photocatalytic by varying the intensity and wavelength of the visible light. The catalyst can be recycled three times. A corresponding photocatalytic mechanism of the oxidation reaction of benzyl alcohol was proposed.

  20. Correlation between the microstructures of graphite oxides and their catalytic behaviors in air oxidation of benzyl alcohol.

    Science.gov (United States)

    Geng, Longlong; Wu, Shujie; Zou, Yongcun; Jia, Mingjun; Zhang, Wenxiang; Yan, Wenfu; Liu, Gang

    2014-05-01

    A series of graphite oxide (GO) materials were obtained by thermal treatment of oxidized natural graphite powder at different temperatures (from 100 to 200 °C). The microstructure evolution (i.e., layer structure and surface functional groups) of the graphite oxide during the heating process is studied by various characterization means, including XRD, N2 adsorption, TG-DTA, in situ DRIFT, XPS, Raman, TEM and Boehm titration. The characterization results show that the structures of GO materials change gradually from multilayer sheets to a transparent ultrathin 2D structure of the carbon sheets. The concentration of surface COH and HOCO groups decrease significantly upon treating temperature increasing. Benzyl alcohol oxidation with air as oxidant source was carried out to detect the catalytic behaviors of different GO materials. The activities of GO materials decrease with the increase of treating temperatures. It shows that the structure properties, including ultrathin sheets and high specific surface area, are not crucial factors affecting the catalytic activity. The type and amount of surface oxygen-containing functional groups of GO materials tightly correlates with the catalytic performance. Carboxylic groups on the surface of GO should act as oxidative sites for benzyl alcohol and the reduced form could be reoxidized by molecular oxygen.

  1. Synthesis and structure-activity relationships of N-benzyl phenethylamines as 5-HT2A/2C agonists

    DEFF Research Database (Denmark)

    Hansen, Martin; Phonekeo, Karina; Paine, James S;

    2014-01-01

    N-benzyl substitution of 5-HT2A receptor agonists of the phenethylamine structural class of psychedelics (such as 4-bromo-2,5-dimethoxyphenethylamine, often referred to as 2C-B) confer a significant increase in binding affinity as well as functional activity of the receptor. We have prepared...... a series of 48 compounds with structural variations in both the phenethylamine and N-benzyl part of the molecule to determine the effects on receptor binding affinity and functional activity at 5-HT2A and 5-HT2C receptors. The compounds generally had high affinity for the 5-HT2A receptor with 8b having......) for the 5-HT2A receptor in the binding assays although one compound 6b showed an impressive 100-fold selectivity for the 5-HT2A receptor. In the functional assay selectivity was generally higher with 1b being more than 400-fold selective for the 5-HT2A receptor....

  2. Content determination of benzyl glucosinolate and anti-cancer activity of its hydrolysis product inCarica papaya L.

    Institute of Scientific and Technical Information of China (English)

    Ze-You Li; Yong Wang; Wen-Tao Shen; Peng Zhou

    2012-01-01

    Objective:To determine the content of benzyl glucosinolate(BG)in the pulp and the seed and investigate the anti-cancer activity of its hydrolysis product inCarica papaya L.Methods:Determination ofBG was performed on an HypersilBDS C18 column at the wavelength of214 nm with0.1% trifluoroacetic acid (TFA)aqueous solution (A) and 0.1%TFA acetonitrile (B)as the mobile phase. In vitro activity test was adopted with cultured human lung cancerH69 cellin vitro to investigate the inhibition rate of cell proliferation of benzyl isothiocyanate(BITC)againstH69 cell.Results: The pulp has more BG before the maturation of papaya and it nearly disappeared after papaya matured, while the seed containsBG at every stage. Activity test demonstrated that the a higher concentration ofBITC would have better inhibition rate of cell proliferation onH69 cell, and the IC50 was6.5 μmol/L.Conclusions:BG also can be produced in the pulp of papaya and it will be stored in the seed after the fruit has been matured. The hydrolysis product ofBG has certain cancer-prevention anti-cancer activities for human.

  3. Detection of a novel neurotoxic metabolite of Parkinson's disease-related neurotoxin, 1-benzyl-1,2,3,4- tetrahydroisoquinoline.

    Science.gov (United States)

    Kotake, Yaichiro; Sekiya, Yoko; Okuda, Katsuhiro; Ohta, Shigeru

    2014-01-01

    Naturally occurring low-molecular weight compounds with a chemical structure like that of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, such as 1-benzyl-1,2,3,4-tetrahydroisoquinoline(1BnTIQ), are candidates for the endogenous neurotoxins that cause Parkinson's disease (PD). 1BnTIQ is an endogenous amine in human CSF and increases in the CSF of patients with PD. It inhibits complex Iand elicits PD-like behavioral abnormalities in monkey and mouse. In this study, we searched metabolites of 1BnTIQ by rat liver S9 using liquid chromatography-tandem mass spectrometry, and identified a dehydrated metabolite, 1-benzyl-3,4-dihydroisoquinoline (1BnDIQ). 1BnDIQ was identified by corresponding mass spectra and precursor ion scans in authentic and complete enzyme samples. Multiple reaction monitoring analysis showed microsome-dependent 1BnDIQ production. We previously reported that 1BnDIQ is more toxic than 1BnTIQ in cytotoxicity study in SH-SY5Y neuroblastoma cells. In addition, 1BnTIQ is reported to pass through the blood-brain barrier of the rat brain, and 1BnDIQ is supposed to be more lipophilic than 1BnTIQ. 1BnDIQ may easily reach the brain, and it might contribute to PD-related neurotoxicity.

  4. COMPLICATIONS OF EXTRAPERITONEOSCOPIC RADICAL PROSTATECTOMIES

    Directory of Open Access Journals (Sweden)

    I. V. Chernyshev

    2012-01-01

    Full Text Available Background. Radical prostatectomy (RPE is today the gold standard treatment option for locally advanced prostate cancer (PC. These operations are performed both openly and using video-assisted endosurgery. Since 2009, the Research Institute of Urology has been made 70 extraperitoneoscopic RPEs (ERPE.Objective: to assess the complications of ERPE with the validated Clavien complication scale.Materials and methods. The authors retrospectively analyzed the case histories of 70 patients with locally advanced PC who had undergone ERPE. The complications were allocated to 3 groups: intraoperative, early (within 1 month and late (over 1 month postoperative ones. All found complications were stratified using Clavien classification scale.Results. The total number of ERPE complications accounted for 35.7%. The most common complications, such as anastomotic incompetence and blood loss that required hemotransfusion, were 9.8 and 11.3%, respectively. Rectal damage was intraoperatively found in 2 cases. Obturator nerve damage was also recognized intraoperatively and did not result in the occurrence of neurological symptoms. The severest complication (Clavien scale grade V was pulmonary embolism causing death.Conclusion. Postoperative complications of ERPE were observed in a small percentage of the patients and posed no serious threat to their life. The analysis of the complications of ERPE suggests that this treatment for locally advanced PC is a current safe and low-traumatic method.

  5. COMPLICATIONS OF EXTRAPERITONEOSCOPIC RADICAL PROSTATECTOMIES

    Directory of Open Access Journals (Sweden)

    I. V. Chernyshev

    2014-08-01

    Full Text Available Background. Radical prostatectomy (RPE is today the gold standard treatment option for locally advanced prostate cancer (PC. These operations are performed both openly and using video-assisted endosurgery. Since 2009, the Research Institute of Urology has been made 70 extraperitoneoscopic RPEs (ERPE.Objective: to assess the complications of ERPE with the validated Clavien complication scale.Materials and methods. The authors retrospectively analyzed the case histories of 70 patients with locally advanced PC who had undergone ERPE. The complications were allocated to 3 groups: intraoperative, early (within 1 month and late (over 1 month postoperative ones. All found complications were stratified using Clavien classification scale.Results. The total number of ERPE complications accounted for 35.7%. The most common complications, such as anastomotic incompetence and blood loss that required hemotransfusion, were 9.8 and 11.3%, respectively. Rectal damage was intraoperatively found in 2 cases. Obturator nerve damage was also recognized intraoperatively and did not result in the occurrence of neurological symptoms. The severest complication (Clavien scale grade V was pulmonary embolism causing death.Conclusion. Postoperative complications of ERPE were observed in a small percentage of the patients and posed no serious threat to their life. The analysis of the complications of ERPE suggests that this treatment for locally advanced PC is a current safe and low-traumatic method.

  6. Study of organic radicals through anion photoelectron velocity-map imaging spectroscopy

    Science.gov (United States)

    Dixon, Andrew Robert

    We report preliminary results on the photoelectron imaging of phenylcarbene, cyanophenylcarbene, and chlorophenylcarbene anions. Triplet phenylcarbene is observed to have an EA of ≤ 0.83 eV, considerably lower than the previously indirectly-determined value. Transitions to the singlet and triplet ground state of both cyanophenylcarbene and chlorophenylcarbene are observable, though unidentified bands make full assignment difficult. Cyanophenylcarbene is found to have a triplet ground-state, with a tentative EA of 2.04 eV. Chlorophenylcarbene is found to have a singlet ground-state. The phenyl-group is found to favor the singlet state slightly. The cyanofluoromethyl radical, FC(H)CN, was estimated to have an EA of 1.53 +/- 0.08 eV, by a combination of experimental and theoretical results.. With similar methodology, we report the adiabatic electron affinity of the cyanobenzyl radical, EA(PhCHCN) = 1.90 +/- 0.01 eV, and assign an upper limit of the EA for the chlorobenzyl radical, EA(PhCHCl) ≤ 1.12 eV. These values were used to estimate the C-H bond dissociation energy (BDE)s for these substituted methanes. Fluoroacetonitrile was found to have a BDE of D H198 = 90.7 +/- 2.8 kcal mol□1. The C-H bond dissociation energies at the benzyl-alpha sites of the phenylmethanes are determined as 80.9 +/- 2.3 kcal mol-1 for benzyl nitrile and an upper limit of 84.2 kcal mol-1 for benzyl chloride. These results are discussed in terms of substituent interactions in a simple MO framework and in relation to other similar molecules, including recently reported results for chloroacetonitrile. The 532 nm photoelectron spectrum of glyoxal provides the first direct spectroscopic determination of the adiabatic electron affinity, EA = 1.10(2) eV. This assignment is supported by a Franck-Condon simulation of the experimental spectrum that successfully reproduces the observed spectral features. The vertical detachment energy (VDE) of the glyoxal radical anion is determined as VDE = 1

  7. Involvement of free radicals in breast cancer.

    Science.gov (United States)

    Ríos-Arrabal, Sandra; Artacho-Cordón, Francisco; León, Josefa; Román-Marinetto, Elisa; Del Mar Salinas-Asensio, María; Calvente, Irene; Núñez, Maria Isabel

    2013-08-27

    Researchers have recently shown an increased interest in free radicals and their role in the tumor microenvironment. Free radicals are molecules with high instability and reactivity due to the presence of an odd number of electrons in the outermost orbit of their atoms. Free radicals include reactive oxygen and nitrogen species, which are key players in the initiation and progression of tumor cells and enhance their metastatic potential. In fact, they are now considered a hallmark of cancer. However, both reactive species may contribute to improve the outcomes of radiotherapy in cancer patients. Besides, high levels of reactive oxygen species may be indicators of genotoxic damage in non-irradiated normal tissues. The purpose of this article is to review recent research on free radicals and carcinogenesis in order to understand the pathways that contribute to tumor malignancy. This review outlines the involvement of free radicals in relevant cellular events, including their effects on genetic instability through (growth factors and tumor suppressor genes, their enhancement of mitogenic signals, and their participation in cell remodeling, proliferation, senescence, apoptosis, and autophagy processes; the possible relationship between free radicals and inflammation is also explored. This knowledge is crucial for evaluating the relevance of free radicals as therapeutic targets in cancer.

  8. Pathways of arachidonic acid peroxyl radical reactions and product formation with guanine radicals.

    Science.gov (United States)

    Crean, Conor; Geacintov, Nicholas E; Shafirovich, Vladimir

    2008-02-01

    Peroxyl radicals were derived from the one-electron oxidation of polyunsaturated fatty acids by sulfate radicals that were generated by the photodissociation of peroxodisulfate anions in air-equilibrated aqueous solutions. Reactions of these peroxyl and neutral guanine radicals, also generated by oxidation with sulfate radicals, were investigated by laser kinetic spectroscopy, and the guanine oxidation products were identified by HPLC and mass spectrometry methods. Sulfate radicals rapidly oxidize arachidonic (ArAc), linoleic (LnAc), and palmitoleic (PmAc) acids with similar rate constants, (2-4) x 10 (9) M (-1) s (-1). The C-centered radicals derived from the oxidation of ArAc and LnAc include nonconjugated Rn(.) ( approximately 80%) and conjugated bis-allylic Rba(.) ( approximately 20%) radicals. The latter were detectable in the absence of oxygen by their prominent, narrow absorption band at 280 nm. The Rn(.) radicals of ArAc (containing three bis-allylic sites) transform to the Rba(.) radicals via an intramolecular H-atom abstraction [rate constant (7.5 +/- 0.7) x 10 (4) s (-1)]. In contrast, the Rn(.) radicals of LnAc that contain only one bis-allylic site do not transform intramolecularly to the Rba(.) radicals. In the case of PmAc, which contains only one double bond, the Rba(.) radicals are not observed. The Rn(.) radicals of PmAc rapidly combine with oxygen with a rate constant of (3.8 +/- 0.4) x 10(9) M(-1) s(-1). The Rba(.) radicals of ArAc are less reactive and react with oxygen with a rate constant of (2.2 +/- 0.2) x 10 (8) M (-1) s (-1). The ArAc peroxyl radicals formed spontaneously eliminate superoxide radical anions [rate constant = (3.4 +/- 0.3) x 10 (4) M (-1) s (-1)]. The stable oxidative lesions derived from the 2',3',5'-tri- O-acetylguanosine or 2',3',5'-tri- O-acetyl-8-oxo-7,8-dihydroguanosine radicals and their subsequent reactions with ArAc peroxyl radicals were also investigated. The major products found were the 2,5-diamino-4 H

  9. Engineering a horseradish peroxidase C stable to radical attacks by mutating multiple radical coupling sites.

    Science.gov (United States)

    Kim, Su Jin; Joo, Jeong Chan; Song, Bong Keun; Yoo, Young Je; Kim, Yong Hwan

    2015-04-01

    Peroxidases have great potential as industrial biocatalysts. In particular, the oxidative polymerization of phenolic compounds catalyzed by peroxidases has been extensively examined because of the advantage of this method over other conventional chemical methods. However, the industrial application of peroxidases is often limited because of their rapid inactivation by phenoxyl radicals during oxidative polymerization. In this work, we report a novel protein engineering approach to improve the radical stability of horseradish peroxidase isozyme C (HRPC). Phenylalanine residues that are vulnerable to modification by the phenoxyl radicals were identified using mass spectrometry analysis. UV-Vis and CD spectra showed that radical coupling did not change the secondary structure or the active site of HRPC. Four phenylalanine (Phe) residues (F68, F142, F143, and F179) were each mutated to alanine residues to generate single mutants to examine the role of these sites in radical coupling. Despite marginal improvement of radical stability, each single mutant still exhibited rapid radical inactivation. To further reduce inactivation by radical coupling, the four substitution mutations were combined in F68A/F142A/F143A/F179A. This mutant demonstrated dramatic enhancement of radical stability by retaining 41% of its initial activity compared to the wild-type, which was completely inactivated. Structure and sequence alignment revealed that radical-vulnerable Phe residues of HPRC are conserved in homologous peroxidases, which showed the same rapid inactivation tendency as HRPC. Based on our site-directed mutagenesis and biochemical characterization, we have shown that engineering radical-vulnerable residues to eliminate multiple radical coupling can be a good strategy to improve the stability of peroxidases against radical attack.

  10. Radical pancreaticoduodenectomy for benign disease.

    LENUS (Irish Health Repository)

    Kavanagh, D O

    2008-01-01

    Whipple\\'s procedure is the treatment of choice for pancreatic and periampullary malignancies. Preoperative histological confirmation of malignancy is frequently unavailable and some patients will subsequently be found to have benign disease. Here, we review our experience with Whipple\\'s procedure for patients ultimately proven to have benign disease. The medical records of all patients who underwent Whipple\\'s procedure during a 15-year period (1987-2002) were reviewed; 112 patients underwent the procedure for suspected malignancy. In eight cases, the final histology was benign (7.1%). One additional patient was known to have benign disease at resection. The mean age was 50 years (range: 30-75). The major presenting features included jaundice (five), pain (two), gastric outlet obstruction (one), and recurrent gastrointestinal haemorrhage (one). Investigations included ultrasound (eight), computerised tomography (eight), endoscopic retrograde cholangiopancreatography (seven; of these, four patients had a stent inserted and three patients had sampling for cytology), and endoscopic ultrasound (two). The pathological diagnosis included benign biliary stricture (two), chronic pancreatitis (two), choledochal cyst (one), inflammatory pseudotumour (one), cystic duodenal wall dysplasia (one), duodenal angiodysplasia (one), and granular cell neoplasm (one). There was no operative mortality. Morbidity included intra-abdominal collection (one), anastomotic leak (one), liver abscess (one), and myocardial infarction (one). All patients remain alive and well at mean follow-up of 41 months. Despite recent advances in diagnostic imaging, 8% of the patients undergoing Whipple\\'s procedure had benign disease. A range of unusual pathological entities can mimic malignancy. Accurate preoperative histological diagnosis may have allowed a less radical operation to be performed. Endoscopic ultrasound-guided fine needle aspirate (EUS-FNA) may reduce the need for Whipple\\'s operation

  11. Psychopathology according to behaviorism: a radical restatement.

    Science.gov (United States)

    Pérez-Alvarez, Marino

    2004-11-01

    This article is a radical restatement of the predominant psychopathology, which is characterized by nosological systems and by its approach towards a neurobiological conception of the so-called mental disorders. The "radical" sense of this restatement is that of radical behaviorism itself. As readers will recall, "radical" applied to behaviorism means total (not ignoring anything that interests psychology), pragmatic (referring to the practical sense of knowledge), and it also derives from the Latin word for "root" (and thus implies change beginning at a system's roots or getting to the root of things, in this case, of psychological disorders). Based on this, I introduce the Aristotelian distinction of material and form, which, besides being behaviorist avant la lettre, is used here as a critical instrument to unmask the hoax of psychopathology as it is presented. The implications of this restatement are discussed, some of them already prepared for clinical practice.

  12. Radicals involved in photoallergen/protein interactions

    Energy Technology Data Exchange (ETDEWEB)

    Delahanty, J.N.; Evans, J.C.; Rowlands, C.C.; Barratt, M.D.; Pendlington, R.U. (University College, Cardiff (England))

    1989-01-01

    Aqueous solutions (pH = 8) of both 3,3'-dimethyl and 4,4'-dimethyl substituted analogues of the photoallergen fentichlor (bis(2-hydroxy-5-chlorophenyl)sulphide) produced stable semiquinone radicals when irradiated with u.v. light (greater than 310 nm). These radicals have been characterised using electron spin resonance techniques: the results confirm the assignment of hyperfine coupling constants for the parent fentichlor radical. The binding of fentichlor to HSA was found to be partly oxygen dependent demonstrating a role for semiquinone type radicals in the binding mechanism. The stoichiometry and specificity of the binding of the dimethyl analogues to soluble proteins were found to be similar to that of fentichlor itself.

  13. Magnetic Trapping of Cold Methyl Radicals

    CERN Document Server

    Liu, Yang; Djuricanin, Pavle; Zhou, Sida; Zhong, Wei; Mittertreiner, Tony; Carty, David; Momose, Takamasa

    2016-01-01

    We have demonstrated that a supersonic beam of methyl radicals (CH3) in the ground rotational state of both para and ortho species has been slowed down to a standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for > 1 s. The translational temperature of the trapped CH3 radicals was about 200 mK. The methyl radical is a non-polar polyatomic molecule, which is predicted to be an ideal system for further cooling below 1 mK via sympathetic cooling with ultracold atoms. In addition, it is a highly reactive intermediate that plays an important role in various processes in cold environments such as planetary atmospheres and the interstellar medium. The demonstrated trapping capability of methyl radicals opens up various possibilities for realizing ultracold ensembles of molecules towards Bose-Einstein condensation of polyatomic molecules and investigations of reactions governed by quantum statistics.

  14. Neo-liberal Governing of 'Radicals'

    DEFF Research Database (Denmark)

    Lindekilde, Lasse

    2012-01-01

    The Danish government’s counter-radicalization Action Plan of 2009 had intended and unintended effects. Primarily targeting Danish Muslims, it employs neoliberal governmentality approaches of governance through individual support and response, information and knowledge, empowerment, surveillance ...

  15. Rigid Ideals and Radicals of Ore Extensions

    Institute of Scientific and Technical Information of China (English)

    Chan Yong Hong; Tai Keun Kwak; S. Tariq Rizvi

    2005-01-01

    For an endomorphism σ of a ring R, Krempa called σ a rigid endomorphism if aσ(a) = 0 implies a= 0 for a ∈ R. A ring R is called rigid if there exists a rigid endomorphism of R. In this paper, we extend the σ-rigid property of a ring R to an ideal of R. For a σ-ideal Ⅰ of a ring R, we call Ⅰ a σ-rigid ideal if aσ(a) ∈Ⅰ implies a ∈Ⅰ for a ∈ R. We characterize σ-rigid ideals and study related properties. The connections of the prime radical and the upper nil radical of R with the prime radical and the upper nil radical of the Ore extension R[x; σ, δ], respectively, are also investigated.

  16. Fast beam studies of free radical photodissociation

    Energy Technology Data Exchange (ETDEWEB)

    Neumark, D.M. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    The authors have developed a novel technique for studying the photodissociation spectroscopy and dynamics of free radicals. In these experiments, radicals are generated by laser photodetachment of a fast (6-8 keV) mass-selected negative ion beam. The resulting radicals are photodissociated with a second laser, and the photofragments are collected and detected with high efficiency using a microchannel plate detector. The overall process is: ABC{sup -} {yields} ABC + e{sup -} {yields} A + BC, AB + C. Two types of fragment detection schemes are used. To map out the photodissociation cross-section of the radical, the photodissociation laser is scanned and the total photofragment yield is measured as a function of wavelength. In other experiments, the photodissociation frequency is fixed and the photofragment masses, kinetic energy release, and scattering angle is determined for each photodissociation event.

  17. Optimal pain management for radical prostatectomy surgery

    DEFF Research Database (Denmark)

    Joshi, Grish P; Jaschinski, Thomas; Bonnet, Francis;

    2015-01-01

    of evidence to develop an optimal pain management protocol in patients undergoing radical prostatectomy. Most studies assessed unimodal analgesic approaches rather than a multimodal technique. There is a need for more procedure-specific studies comparing pain and analgesic requirements for open and minimally......BACKGROUND: Increase in the diagnosis of prostate cancer has increased the incidence of radical prostatectomy. However, the literature assessing pain therapy for this procedure has not been systematically evaluated. Thus, optimal pain therapy for patients undergoing radical prostatectomy remains...... invasive surgical procedures. Finally, while we wait for appropriate procedure specific evidence from publication of adequate studies assessing optimal pain management after radical prostatectomy, we propose a basic analgesic guideline....

  18. Radicalization and the Use of Social Media

    Directory of Open Access Journals (Sweden)

    Robin Thompson

    2011-01-01

    Full Text Available The use of social media tools by individuals and organizations to radicalize individuals for political and social change has become increasingly popular as the Internet penetrates more of the world and mobile computing devices are more accessible. To establish a construct for radicalization,the power and reach of social media will be described so there is common understanding of what social media is and how it is utilized by various individuals and groups. The second section will answer the question of why social media applications are the perfect platform for the radical voice. Finally, the use of social media and its influence in radicalizing populations in Northern Africa and the Middle East during 2011 will be analyzed and recommendations proposed.

  19. Adsorption of alkyl-dimethyl-benzyl-ammonium chloride on low-weight greige and bleached cotton nonwovens in different aqueous environments

    Science.gov (United States)

    Previous research has shown the adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) on cotton nonwovens is dependent on pretreatment of the substrate, more specifically whether it is greige or bleached fabric. In this work we examine the effect of varying the chemical and physical propert...

  20. Correlation between disintegration, dissolution and in vivo absorption rate in the case of compounds with benzyl-isoquinoline structures and its pharmacokinetic aspects.

    Science.gov (United States)

    Marton, S; Szentmiklósi, P; Rácz, I

    1984-01-01

    Investigations have proved that in the case of po preparations disintegration time, dissolution rate and in vivo absorption rate are closely interrelated. These correlations described by adequate mathematical formulas are valid in the case of papaverine, drotaverine and Depogen--compounds with benzyl-isoquinoline structure.

  1. Effect of polyester blends in hydroentangled raw and bleached cotton nonwoven fabrics on the adsorption of alkyl-dimethyl-benzyl-ammonium chloride

    Science.gov (United States)

    The adsorption kinetics and isotherms of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on hydroentangled nonwoven fabrics (applicable for wipes) including raw cotton, bleached cotton, and their blends with polyester (PES) were stu...

  2. Effect of varying nonwoven cotton substrate and the properties of the surfactant solution upon the adsorption of aqueous solutions of alkyl-dimethyl-benzyl-ammonium chloride

    Science.gov (United States)

    The adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on greige, alkaline scoured, and bleached nonwoven cotton fabrics was investigated at varying surfactant concentrations and liquor ratios using UV-vis absorption spec...

  3. The Synthesis of "N"-Benzyl-2-Azanorbornene via Aqueous Hetero Diels-Alder Reaction: An Undergraduate Project in Organic Synthesis and Structural Analysis

    Science.gov (United States)

    Sauvage, Xavier; Delaude, Lionel

    2008-01-01

    The synthesis of "N"-benzyl-2-azanorbornene via aqueous hetero Diels-Alder reaction of cyclopentadiene and benzyliminium chloride formed in situ from benzylamine hydrochloride and formaldehyde is described. Characterization of the product was achieved by IR and NMR spectroscopies. The spectral data acquired are thoroughly discussed. Numerous…

  4. Molecular modeling and experimental studies on structure and NMR parameters of 9-benzyl-3,6-diiodo-9H-carbazole

    DEFF Research Database (Denmark)

    Radula-Janik, Klaudia; Kupka, Teobald; Ejsmont, Krzysztof;

    2015-01-01

    A combined experimental and theoretical study has been performed on 9-benzyl-3,6-diiodo-9H-carbazole. Experimental X-ray (100.0 K) and room-temperature 13C NMR studies were supported by advanced density functional theory (DFT) calculations. The non relativistic structure optimization was performe...

  5. Reusable ionic liquid-catalyzed oxidative coupling of azoles and benzylic compounds via sp(3) C-N bond formation under metal-free conditions.

    Science.gov (United States)

    Liu, Wenbo; Liu, Chenjiang; Zhang, Yonghong; Sun, Yadong; Abdukadera, Ablimit; Wang, Bin; Li, He; Ma, Xuecheng; Zhang, Zengpeng

    2015-07-14

    The heterocyclic ionic liquid-catalyzed direct oxidative amination of benzylic sp(3) C-H bonds via intermolecular sp(3) C-N bond formation for the synthesis of N-alkylated azoles under metal-free conditions is reported for the first time. The catalyst 1-butylpyridinium iodide can be recycled and reused with similar efficacies for at least eight cycles.

  6. Selective liquid phase oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide over γ-Al2O3 supported copper and gold nanoparticles

    Science.gov (United States)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout

    2017-03-01

    Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide (TBHP) in the absence of any solvent using γ-Al2O3 supported copper and gold nanoparticles. Li2O and ionic liquids were used as additive and stabilizers for the synthesis of the catalysts. The physico-chemical properties of the catalysts were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction spectroscopy (XRD), N2 absorption/desorption (BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and temperature programmed reduction (TPR), whereas, the oxidation reaction was followed by gas chromatography with a flame ionization detector (GC-FID). The as prepared catalysts exhibited good catalytic performance in terms of conversion and selectivity towards benzaldehyde. The performance of the Au-based catalysts is significantly higher than that of the Cu-based catalysts. For both Cu and Au catalysts, the conversion of benzyl alcohol increased as the reaction proceeds, while the selectivity for benzaldehyde decreased. Moreover, the catalysts can be easily recycled and reused with neither significant loss of activity nor selectivity. A kinetic study for the Cu and Au-catalyzed oxidation of benzyl alcohol to benzyldehyde is reported. The rate at which the oxidation of benzyl alcohol is occurring as a function of catalyst and oxidant amounts was investigated, with the apparent rate constant, kapp being proportional to the amount of nano catalyst and oxygen present in the system.

  7. SiO2-Cu2O:An efficient and recyclable heterogeneous catalyst for N-benzylation of primary and secondary amines

    Institute of Scientific and Technical Information of China (English)

    Manjulla Gupta; Satya Paul; Rajive Gupta

    2014-01-01

    A mild, effective, and selective procedure is reported for the mono N-benzylation and N,N- diben-zylation of primary amines as well as mono N-benzylation of secondary amines using sili-ca-supported copper(I) oxide in water. The silica-supported Cu2O was generated in situ by the reac-tion of Fehling solution and glucose at 100 °C onto activated silica. The catalyst was filtered, washed with water, and oven-dried, and was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic absorption spectroscopy. The prepared Cu2O-SiO2 was found to be thermally stable up to 325 °C. The copper was uniformly distributed onto the surface of the silica, and the mean particle diameter was 7 nm. The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines. The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity. Various reaction solvents including water, acetonitrile, and toluene were screened for N-benzylation of amines, and the success of the aqueous system highlights the low environmental impact of the procedure.

  8. Adsorption of a benzylic amide macrocycle on a solid substrate : XPS and HREELS characterization of thin films grown on Au(111)

    NARCIS (Netherlands)

    Whelan, Caroline M.; Cecchet, Francesca; Baxter, Richard; Zerbetto, Francesco; Clarkson, Guy J.; Leigh, David A.; Rudolf, Petra

    2002-01-01

    Thin films of a benzylic amide macrocycle, the common component of a wide class of mechanically interlocked molecules, are prepared by vapor deposition on Au(111). The films are characterized by monochromated X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscop

  9. An efficient oxidation of benzylic and alicylic compounds with water-soluble copper catalysts in t-butyl hydroperoxide at room temperature

    Institute of Scientific and Technical Information of China (English)

    Ateeq Rahman; S. M. Al Zahrani; Abdel Aziz Nait Ajjou

    2011-01-01

    The water soluble catalytic system comprising of CuCl2 and 2,2-biquinoline-4,4-dicarboxylic acid dipotassium salt (BQC) is highly efficient organic metallic catalysts for selective oxidation of benzylic and alicyclic compounds to the corresponding ketones, ex: indan to indanone, ethyl benzene to acetophenone.

  10. Hydroxyl radical generation by red tide algae.

    Science.gov (United States)

    Oda, T; Akaike, T; Sato, K; Ishimatsu, A; Takeshita, S; Muramatsu, T; Maeda, H

    1992-04-01

    The unicellular marine phytoplankton Chattonella marina is known to have toxic effects against various living marine organisms, especially fishes. However, details of the mechanism of the toxicity of this plankton remain obscure. Here we demonstrate the generation of superoxide and hydroxyl radicals from a red tide unicellular organism, C. marina, by using ESR spectroscopy with the spin traps 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and N-t-butyl-alpha-phenylnitrone (PBN), and by using the luminol-enhanced chemiluminescence response. The spin-trapping assay revealed productions of spin adduct of superoxide anion (O2-) (DMPO-OOH) and that of hydroxyl radical (.OH) (DMPO-OH) in the algal suspension, which was not observed in the ultrasonic-ruptured suspension. The addition of superoxide dismutase (500 U/ml) almost completely inhibited the formation of both DMPO-OOH and DMPO-OH, and carbon-centered radicals were generated with the disappearance of DMPO-OH after addition of 5% dimethyl sulfoxide (Me2SO) and 5% ethanol. Furthermore, the generation of methyl and methoxyl radicals, which are thought to be produced by the reaction of hydroxyl radical and Me2SO under aerobic condition, was identified using spin trapping with a combination of PBN and Me2SO. Luminol-enhanced chemiluminescence assay also supported the above observations. These results clearly indicate that C. marina generates and releases the superoxide radical followed by the production of hydroxyl radical to the surrounding environment. The velocity of superoxide generation by C. marina was about 100 times faster than that by mammalian phagocytes per cell basis. The generation of oxygen radical is suggested to be a pathogenic principle in the toxication of red tide to susceptible aquaculture fishes and may be directly correlated with the coastal pollution by red tide.

  11. Catalytic Radical Domino Reactions in Organic Synthesis

    Science.gov (United States)

    Sebren, Leanne J.; Devery, James J.; Stephenson, Corey R.J.

    2014-01-01

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes. PMID:24587964

  12. Moment matrices, border bases and radical computation

    OpenAIRE

    Mourrain, B.; J. B. Lasserre; Laurent, Monique; Rostalski, P.; Trebuchet, Philippe

    2013-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming. While the border basis algorithms of [17] are ecient and numerically stable for computing complex roots, algorithms based on moment matrices [12] allow the incorporation of additional polynomials, ...

  13. Free Radical Mechanisms of Xenobiotic Mammalian Cytotoxicities

    Science.gov (United States)

    1991-06-30

    frequent mechanism of xenobiotic liver toxicity is biotransformation by cytochrome P,5o- enzymes to toxic free radical intermediates. The primary objective...vascular cells was to incubate the cells with both the spin trapping agent methyl nitroso propane ( MNP ) and IRP chemicals to determine if free radical...gave a reasonably strong MNP -adduct signal. Figure 1 gives the MNP adduct signal for carbon tetrachloride and trichloroethylene, as well as that for

  14. Inactivation of Bacillus atrophaeus by OH radicals

    Science.gov (United States)

    Ono, Ryo; Yonetamari, Kenta; Tokumitsu, Yusuke; Yonemori, Seiya; Yasuda, Hachiro; Mizuno, Akira

    2016-08-01

    The inactivation of Bacillus atrophaeus by OH radicals is measured. This study aims to evaluate the bactericidal effects of OH radicals produced by atmospheric-pressure nonthermal plasma widely used for plasma medicine; however, in this study, OH radicals are produced by vacuum ultraviolet (VUV) photolysis of water vapor instead of plasma to allow the production of OH radicals with almost no other reactive species. A 172 nm VUV light from a Xe2 excimer lamp irradiates a He-H2O mixture flowing in a quartz tube to photodissociate H2O to produce OH, H, O, HO2, H2O2, and O3. The produced reactive oxygen species (ROS) flow out of the quartz tube nozzle to the bacteria on an agar plate and cause inactivation. The inactivation by OH radicals among the six ROS is observed by properly setting the experimental conditions with the help of simulations calculating the ROS densities. A 30 s treatment with approximately 0.1 ppm OH radicals causes visible inactivation.

  15. Oxygen radicals, inflammation, and tissue injury.

    Science.gov (United States)

    Ward, P A; Warren, J S; Johnson, K J

    1988-01-01

    Inflammatory reactions often result in the activation and recruitment of phagocytic cells (e.g., neutrophils and/or tissue macrophages) whose products result in injury to the tissue. In killing of endothelial cells by activated neutrophils as well as in lung injury produced by either activated neutrophils or activated macrophages there is evidence that H2O2 and iron play a role. HO. may be a key oxygen product related to the process of injury. Endothelial cells in some vascular compartments may be susceptible to neutrophil mediated injury in a manner that is independent of oxygen radicals. On the basis of in vitro observations, a synergy exits between platelets and neutrophils, resulting in enhanced oxygen radical formation by the latter. Finally, the cytokines, interleukin 1 and tumor necrosis factor, released from macrophages have both direct stimulatory effects on oxygen radical formation in neutrophils and can "prime" macrophages for enhanced oxygen radical responses to other agonists. Cytokines may also alter endothelial cells rendering them more susceptible to oxygen radical mediated injury by neutrophils. This suggests a complex network of interactions between phagocytic cells and peptide mediators, the result of which is acute, oxygen radical mediated tissue injury.

  16. Free radicals in biology. Volume III

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. (ed.)

    1977-01-01

    This volume covers topics ranging from radiation chemistry to biochemistry, biology, and medicine. This volume attempts to bridge the gap between chemical investigations and the medical applications and implications of free radical reactions. Chapter 1 provides a general introduction to the technique of radiation chemistry, the thermodynamics and kinetic factors that need be considered, the use of pulse radiolysis and flow techniques, and the application of these methods to free radicals of biological interest. Chapter 3 discusses the mechanisms of carbon tetrachloride toxicity. Chapter 4 reviews the morphological, histochemical, biochemical, and chemical nature of lipofuscin pigments. This chapter brings together the evidence that lipofuscin pigments arise from free radical pathology and that the formation of these pigments proves the presence of lipid peroxidation in vivo. Chapter 5 reviews the evidence for production of free (i.e., scavengeable) radicals from the reactions of selected enzymes with their substrates. Chapter 6 discusses one of the systems in which free radical damage is clearly important in vivo, both for man and animal, the damage caused to skin by sunlight. The evidence that free radical reactions can contribute to carcinogenesis dates from the earliest observations that ionizing radiation often produces higher incidences of tumors. A current working hypothesis is that chemical toxins cause damage to DNA and that the repair of this damge may incorporate viral genetic information into the host cell's chromosomes, producing cell transformation and cancer. The mechanism whereby chemical carcinogens become bound to DNA to produce point defects is discussed in Chapter 7.

  17. Radical Scavenging Effects of Different Veronica species

    Directory of Open Access Journals (Sweden)

    Ummuhan Şebnem Harput

    2011-01-01

    Full Text Available It is well known that the excessive production of reactive oxygen species is hazardous for living organisms and damages major cellular constituents such as DNA, lipid and protein. To find new products reducing free radical damage is very important researches in recent pharmaceutical investigations. Considering this information, fourteen Veronica species are decided to research in the view point of their antioxidant capacity and the chemical content. Water extracts of the plants were tested for their radical scavenging activity against 2,2-diphenyl-1-picryl hydrazyl (DPPH, superoxide (SO and nitric oxide (NO radicals spectroscopically. Dose dependent radical scavenging activity was observed and the results were found to be comparable to that of ascorbic acid, quercetin and BHA which are known antioxidative compounds. In addition, gallic acid equivalent total phenolic contents of the plants were also determined using Folin-Ciocalteau reagent. The most significant scavenging activity was found for V. chamaedrys against SO radical (IC50 113.40 μg/ml and V. officinalis against DPPH and NO radicals (IC50 40.93 μg/ml, 570.33 μg/ml, respectively .

  18. Radioprotective thermally generated free-radical dextrins

    Institute of Scientific and Technical Information of China (English)

    Piotr TOMASIK; Oskar MICHALSKI; Ewa BIDZINSKA; Antonina CEBULSKA-WASILEWSKA; Krystyna DYREK; Maciej FIEDOROWICZ; Pawel OLKO

    2008-01-01

    Effect of doses of the X-ray radiation from 0 to 400 Gy upon granular cornstarch and dextrins (British gums, BG) thermally generated from it at 230-300℃ was recognized with quantitative EPR and IR ab-sorption spectroscopy, molecular mass distribution in the depolymerization products, Scanning Elec-tron Microscopy, and X-ray diffractometry. Fractal analysis of the profiles of molecular mass distribu-tion showed that the depolymerization involved debranching of amylopectin. Roasting of cornstarch produced BG which differed in concentration and EPR parameters of stable free radicals from BG generated by X-ray radiation. Two types of stable free radicals, with Gaussian and Lorentzian shapes of EPR signals, were recognized. The shapes of the signals and temperature dependence on free radical intensity indicated exchanging interactions of the antiferromagnetic type, causing partial quenching of the spins at -196℃ (77K). Upon X-ray irradiation, new radicals were generated, the number and stability of which strongly depended on the types of radicals present before irradiation. These radicals slowly ceased because of a repolymerization of BG on storage.

  19. Novel Nonsymmetrically p-Benzyl-Substituted (Benzimidazole N-Heterocyclic Carbene-Silver(I Acetate Complexes: Synthesis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Frauke Hackenberg

    2012-01-01

    Full Text Available Nonsymmetrically substituted N-heterocyclic carbene (NHC precursors 1a–d and 3a–d were synthesised by first reacting 1H-(benzimidazole with p-cyanobenzyl bromide to give 4-(1H-imidazole-1-ylmethylbenzonitrile (1 and 4-(1H-benzimidazole-1-ylmethylbenzonitrile (3 and afterwards introducing benzyl bromide, 1-(bromomethyl-4-methylbenzene, 1-(bromomethyl-4-methoxybenzene, and methyl 4-(bromomethylbenzoate. The NHC-silver(I acetate complexes (1-benzyl-3-(4-cyanobenzyl-2,3-dihydro-1H-imidazole-2-ylidene silver(I acetate (2a, (1-(4-cyanobenzyl-3-(4-methylbenzyl-2,3-dihydro-1H-imidazole-2-ylidene silver(I acetate (2b, (1-(4-cyanobenzyl-3-[4-(methoxycarbonylbenzyl]-2,3-dihydro-1H-imidazole-2-ylidene silver(I acetate (2c, (1-benzyl-3-(4-cyanobenzyl-2,3-dihydro-1H-benzimidazole-2-ylidene silver(I acetate (4a, (1-(4-cyanobenzyl-3-(4-methylbenzyl-2,3-dihydro-1H-benzimidazole-2-ylidene silver(I acetate (4b, (1-(4-cyanobenzyl-3-(4-methoxybenzyl-2,3-dihydro-1H-benzimidazole-2-ylidene silver(I acetate (4c, and (1-(4-cyanobenzyl-3-[4-(methoxycarbonylbenzyl]-2,3-dihydro-1H-benzimidazole-2-ylidene silver(I acetate (4d were yielded by reacting these NHC precursors with silver(I acetate. The silver(I acetate complex 4b was characterised by single crystal X-ray diffraction. Preliminary in vitro antibacterial studies against the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli, using the Kirby-Bauer disc diffusion method, were carried out on the seven NHC-silver(I acetate complexes 2a–c and 4a–d. Also the IC50 values of these seven complexes were determined by an MTT-based assay against the human renal cancer cell line Caki-1. The complexes 2a–c and 4a–c revealed the following IC50 values, respectively, 25 (±1, 15 (±2, 5.4 (±0.8, 16 (±2, 7.1 (±1, 20 (±4, and 14 (±1 μM.

  20. Crystal structure of 3-O-benzyl-4(R-C-(1-benzyl-1H-1,2,3-triazol-4-yl-1,2-O-isopropylidene-α-d-erythrofuranose

    Directory of Open Access Journals (Sweden)

    Nikita Semjonovs

    2015-12-01

    Full Text Available The title compound, C23H25N3O4, {systematic name: 1-benzyl-4-[(3aR,5R,6R,6aR-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl]-1H-1,2,3-triazole}, consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole. The furanose ring adopts an envelope conformation close to C3-exo, where the C atom substituted by the benzyloxy group is the flap. The fused dioxolane ring also adopts an envelope conformation, with the methylene C atom as the flap. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming zigzag chains along [010].

  1. Radicalization and Radical Catalysis of Biomass Sugars: Insights from First-principles Studies

    Science.gov (United States)

    Yang, Gang; Zhu, Chang; Zou, Xianli; Zhou, Lijun

    2016-07-01

    Ab initio and density functional calculations are conducted to investigate the radicalization processes and radical catalysis of biomass sugars. Structural alterations due to radicalization generally focus on the radicalized sites, and radicalization affects H-bonds in D-fructofuranose more than in D-glucopyranose, potentially with outcome of new H-bonds. Performances of different functionals and basis sets are evaluated for all radicalization processes, and enthalpy changes and Gibbs free energies for these processes are presented with high accuracy, which can be referenced for subsequent experimental and theoretical studies. It shows that radicalization can be utilized for direct transformation of biomass sugars, and for each sugar, C rather than O sites are always preferred for radicalization, thus suggesting the possibility to activate C-H bonds of biomass sugars. Radical catalysis is further combined with Brønsted acids, and it clearly states that functionalization fundamentally regulates the catalytic effects of biomass sugars. In presence of explicit water molecules, functionalization significantly affects the activation barriers and reaction energies of protonation rather than dehydration steps. Tertiary butyl and phenyl groups with large steric hindrances or hydroxyl and amino groups resulting in high stabilities for protonation products drive the protonation steps to occur facilely at ambient conditions.

  2. High efficient photocatalytic selective oxidation of benzyl alcohol to benzaldehyde by solvothermal-synthesized ZnIn{sub 2}S{sub 4} microspheres under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhixin, E-mail: czx@fzu.edu.cn [State Key Laboratory Breeding Base of Photocatalysis, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002 (China); Instrumental Measurement and Analysis Center, Fuzhou University, Fuzhou 350002 (China); Xu, Jingjing; Ren, Zhuyun [State Key Laboratory Breeding Base of Photocatalysis, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002 (China); He, Yunhui; Xiao, Guangcan [State Key Laboratory Breeding Base of Photocatalysis, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002 (China); Instrumental Measurement and Analysis Center, Fuzhou University, Fuzhou 350002 (China)

    2013-09-15

    Hexagonal ZnIn{sub 2}S{sub 4} samples have been synthesized by a solvothermal method. Their properties have been determined by X-ray diffraction, ultraviolet–visible-light diffuse reflectance spectra, field emission scanning electron microscopy, nitrogen adsorption–desorption and X-ray photoelectron spectra. These results demonstrate that ethanol solvent has significant influence on the morphology, optical and electronic nature for such marigold-like ZnIn{sub 2}S{sub 4} microspheres. The visible light photocatalytic activities of the ZnIn{sub 2}S{sub 4} have been evaluated by selective oxidation of benzyl alcohol to benzaldehyde using molecular oxygen as oxidant. The results show that 100% conversion along with >99% selectivity are reached over ZnIn{sub 2}S{sub 4} prepared in ethanol solvent under visible light irradiation (λ>420 nm) of 2 h, but only 58% conversion and 57% yield are reached over ZnIn{sub 2}S{sub 4} prepared in aqueous solvent. A possible mechanism of the high photocatalytic activity for selective oxidation of benzyl alcohol over ZnIn{sub 2}S{sub 4} is proposed and discussed. - Graphical abstract: Marigold-like ZnIn{sub 2}S{sub 4} microspheres were synthesized by a solvothermal method. The high visible photocatalytic activities of ZnIn{sub 2}S{sub 4} were evaluated by selective oxidation of benzyl alcohol to benzaldehyde under mild conditions. Display Omitted - Highlights: • Marigold-like ZnIn{sub 2}S{sub 4} microspheres were synthesized by a solvothermal method. • The solvents have a remarkably influence on the morphology and properties of samples. • It is the first time to apply ZnIn{sub 2}S{sub 4} for selective oxidation of benzyl alcohol. • ZnIn{sub 2}S{sub 4} shows high photocatalytic activity for selective oxidation of benzyl alcohol.

  3. Photoinduced and Thermal Reactions of α-Cyano-β-bromomethylcinnamide with 1-Benzyl- 1,4-dihydronicotinamide

    Institute of Scientific and Technical Information of China (English)

    DAI,Dan-Mei(代丹梅); LIU,You-Cheng(刘有成); LI,Jing(李劲)

    2001-01-01

    The photoinduced reaction of a mixture of ( Z )-α-cyano-β-bromonethylcinnamide (1) and ( E)-α-cyano-βbromomethylcinnamide (2) with 1-benzyl-1,4-dihydronicotinamide pro-duces a mixture of the (E)- and (Z)- isomers of α-cyan-βmethylcinnamide (3 and 4).Using spin-trapping technique formonitoring reactive internediate,it is shown that the reactionproceeds via electron transfer-debromination-H abstractionmechanism.The thermal reaction of the same substrate withBNAH at 60℃ in the dark gives three products: the ( E )- and(Z)-isomers of α-cyano-β-methylcinnamide and a dehy-drodimeric product: 2,7-dicyano-3,6-diphenylocta-2,4,6-trien-1.8-dioic amide (7).Based on product analysis,scav-enger experiment and cyclic voltammetry,an electron trans-fer-debronination-disproportionafion mechanisn is proposed.``

  4. Synthesis and Crystal Structure of N-Benzyl-N'-(2-pyridyl)urea and Its Mononuclear Cu(II) Complex

    Institute of Scientific and Technical Information of China (English)

    HE Lei; LUO Xiao-Lan; ZHANG Wen-Qin

    2008-01-01

    A new ligand of N-benzyl-N'-(2-pyridyl)urea L and its self-assembly product with CuCl2, [Cu(II)LCl2]∞ 1, have been synthesized and structurally characterized by IR, 1H NMR and single-crystal X-ray diffraction analysis. In the structure of L, the urea groups adopt Z,E conformation to form dimers through intermolecular hydrogen bonds; while in complex 1, it assumes Z,Z conformation to fit for the coordination sphere of the Cu(II) ions. The coordinated units are connected through intermolecular N-H…Cl hydrogen bonds to form an extended 2D framework. Finally, a 3D structure is obtained via π-π stacking interactions between pyridyl rings.

  5. Synthesis and anticholinergic activity of 4-hydroxycoumarin derivatives containing substituted benzyl-1,2,3-triazole moiety.

    Science.gov (United States)

    Bagheri, Sahar Mohammad; Khoobi, Mehdi; Nadri, Hamid; Moradi, Alireza; Emami, Saeed; Jalili-Baleh, Leili; Jafarpour, Farnaz; Homayouni Moghadam, Farshad; Foroumadi, Alireza; Shafiee, Abbas

    2015-11-01

    A series of 4-hydroxycoumarin-derived compounds 8a-p containing N-benzyl-1,2,3-triazole motif were designed as AChE inhibitors. The title compounds were obtained conveniently using multicomponent click reaction. The in vitro anticholinesterase evaluation of synthesized compounds against AChE and BuChE showed that some of them are potent and selective inhibitors of AChE. Among them, 2-chlorobenzyl derivative 8k showed the most potent activity against AChE (IC50  = 0.18 μm). Its activity was also superior to that of standard drug tacrine. The kinetic study and molecular docking simulation of the most potent compound 8k were also described.

  6. Predicting antiprotozoal activity of benzyl phenyl ether diamine derivatives through QSAR multi-target and molecular topology.

    Science.gov (United States)

    Garcia-Domenech, Ramon; Zanni, Riccardo; Galvez-Llompart, Maria; Galvez, Jorge

    2015-05-01

    Multi-target QSAR is a novel approach that can predict simultaneously the activity of a given chemical compound on different pharmacological targets. In this work, we have used molecular topology and statistical tools such as multilinear regression analysis and artificial neural networks, to achieve a multi-target QSAR model capable to predict the antiprotozoal activity of a group of benzyl phenyl ether diamine derivatives. The activity was related to three parasites with a high prevalence rate in humans: Trypanosoma brucei rhodesiense, Plasmodium falciparum, and Leishmania donovani. The multi-target model showed a high regression coefficient (R(2) = 0.9644 and R(2) = 0.9235 for training and test sets, respectively) and a low standard error of estimate (SEE = 0.279). Model validation was performed with an external test (R(2) = 0.9001) and a randomization analysis. Finally, the model was applied to the search of potential new active compounds.

  7. Synthesis and biological evaluation of novel benzyl-substituted (S)-phenylalanine derivatives as potent dipeptidyl peptidase 4 inhibitors.

    Science.gov (United States)

    Liu, Yang; Si, Meimei; Tang, Li; Shangguan, Shihao; Wu, Haoshu; Li, Jia; Wu, Peng; Ma, Xiaodong; Liu, Tao; Hu, Yongzhou

    2013-09-15

    A series of novel benzyl-substituted (S)-phenylalanine derivatives were synthesized and evaluated for their dipeptidyl peptidase 4 (DPP-4) inhibitory activity and selectivity. It was found that most synthesized target compounds were potent DPP-4 inhibitors with IC50 values in 3.79-25.52 nM, which were significantly superior to that of the marketed drug sitagliptin. Furthermore, the 4-fluorobenzyl substituted phenylalanine derivative 6g not only displayed the potent DPP-4 inhibition with an IC50 value of 3.79 nM, but also showed better selectivity against DPP-4 over other related enzymes including DPP-7, DPP-8, and DPP-9. In an oral glucose tolerance test (OGTT) in normal Sprague Dawley rats, compound 6g reduced blood glucose excursion in a dose-dependent manner.

  8. Enantioselective Benzylic Hydroxylation Catalysed by P450 Monooxygenases: Characterisation of a P450cam Mutant Library and Molecular Modelling.

    Science.gov (United States)

    Eichler, Anja; Gricman, Łukasz; Herter, Susanne; Kelly, Paul P; Turner, Nicholas J; Pleiss, Jürgen; Flitsch, Sabine L

    2016-03-02

    Cytochrome P450 monooxygenases can catalyse the stereoselective C-H activation of a very broad range of substrates. Prediction and control of enantioselectivity of this enzyme class is of great interest for the synthesis of high-value chiral molecules. Here we have used a combination of molecular dynamics simulations and experimental screening to study the enantioselectivity of a library of active-site mutants of chimeric P450cam-RhFRed towards the benzylic hydroxylation of structurally related regioisomers of ethylmethylbenzene. Small variations either in substrate structure or in enzyme active site architecture were shown to lead to dramatic changes in enantioselectivity; this was broadly in agreement with computational predictions. In addition to validating computational approaches, these studies have provided us with a deeper understanding of effects that might control stereoselectivity in these biooxidation reactions.

  9. Structure of HIV-1 nonnucleoside reverse transcriptase inhibitors derivatives of N-benzyl-benzimidazole with different substituents in position 4

    Science.gov (United States)

    Ziółkowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

    2010-01-01

    The constant development of new drugs against HIV-1 is necessary due to global expansion of AIDS and HIV-1 drug resistance. Nonnucleoside reverse transcriptase inhibitors of HIV-1 (NNRTIs) are potentially effective and nontoxic drugs in AIDS therapy. The crystal structures of six nonnucleoside inhibitors of HIV-1 reverse transcriptase (RT) derivatives of N-benzyl-benzimidazole are reported here. The investigated compounds belong to the group of so called "butterfly like" inhibitors with characteristic two π-electron moieties with an angled orientation. The structural data show the influence of the substituents of the benzimidazole ring on the geometry of the molecule and correlation between the structure of the inhibitor and its biological activity.

  10. Polymer-clay nanocomposites obtained by solution polymerization of vinyl benzyl triammonium chloride in the presence of advanced functionalized clay

    Indian Academy of Sciences (India)

    Raluca Ianchis; Dan Donescu; Ludmila Otilia Cinteza; Violeta Purcar; Cristina Lavinia Nistor; Critian Petcu; Cristian Andi Nicolae; Raluca Gabor; Silviu Preda

    2014-05-01

    Polymer-clay nanocomposites were synthesized by solution polymerization method using advanced functionalized clay and vinyl benzyl trimethyl ammonium chloride as monomer. First stage consisted in the silylation of a commercial organo-modified clay-Cl 20A using alkoxysilanes with different chain lengths. In the second step, the synthesis and characterization of polymer-nanocomposites were followed. To evaluate the clay functionalization process as well as the final polymer-clay products, thermogravimetric,X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy and three test liquid contact angles analyses were used. The loss of ammonium ions from commercial clay, the grafting degree, the lengths and the nature of alkyl chain influence the dispersion of the advanced modified clay into the polymer solution and, furthermore, the properties of the final polymer-clay nanocomposite film.

  11. Gold & silver nanoparticles supported on manganese oxide: Synthesis, characterization and catalytic studies for selective oxidation of benzyl alcohol

    Directory of Open Access Journals (Sweden)

    Saad Alabbad

    2014-12-01

    Full Text Available Nano-gold and silver particles supported on manganese oxide were synthesized by the co-precipitation method. The catalytic properties of these materials were investigated for the oxidation of benzyl alcohol using molecular oxygen as a source of oxygen. The catalyst was calcined at 300, 400 and 500 °C. They were characterized by electron microscopy, powder X-ray diffraction (XRD and surface area. It was observed that the calcination temperature affects the size of the nanoparticle, which plays a significant role in the catalytic process. The catalyst calcined at 400 °C, gave a 100% conversion and >99% selectivity, whereas catalysts calcined at 300 and 500 °C gave a conversion of 69.51% and 19.90% respectively, although the selectivity remains >99%.

  12. Multichromic conducting copolymer of 1-benzyl-2,5-di(thiophen-2-yl)-1H-pyrrole with EDOT

    Energy Technology Data Exchange (ETDEWEB)

    Camurlu, Pinar [Department of Chemistry, Akdeniz University, 07058 Antalya (Turkey); Tarkuc, Simge; Akhmedov, idris Mecidoglu; Tanyeli, Cihangir; Toppare, Levent [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Sahmetlioglu, Ertugrul [Department of Chemistry, Nigde University, 51100 Nigde (Turkey)

    2008-02-15

    Despite the significant progress made in the field of electrochromic polymers, the multichromic facility of current knowledge is restricted. Therefore, as previously proven, electrochemical copolymerization of 1-benzyl-2,5-di(thiophen-2-yl)-1H-pyrrole (SNBS) and 3,4-ethylenedioxythiophene (EDOT) was used as a strategy to achieve desired multichromic properties, where the resultant copolymer displayed distinct color changes between claret red, yellow, green, and blue colors with short switching times and high optical contrast. As an application, absorption/transmission type electrochromic device with indium tin oxide (ITO)/copolymer/gel electrolyte PEDOT/ITO configuration was constructed, where copolymer and PEDOT functioned as the anodically and the cathodically coloring layers, respectively. Results implied the successive use of this copolymer in electrochromic device applications, since the device exhibited short switching times with a wide color variation upon applied potential. (author)

  13. 1-Benzyl-2-Phenylbenzimidazole (BPB, a Benzimidazole Derivative, Induces Cell Apoptosis in Human Chondrosarcoma through Intrinsic and Extrinsic Pathways

    Directory of Open Access Journals (Sweden)

    Ju-Fang Liu

    2012-12-01

    Full Text Available In this study, we investigated the anticancer effects of a new benzimidazole derivative, 1-benzyl-2-phenyl -benzimidazole (BPB, in human chondrosarcoma cells. BPB-mediated apoptosis was assessed by the MTT assay and flow cytometry analysis. The in vivo efficacy was examined in a JJ012 xenograft model. Here we found that BPB induced apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353 but not in primary chondrocytes. BPB induced upregulation of Bax, Bad and Bak, downregulation of Bcl-2, Bid and Bcl-XL and dysfunction of mitochondria in chondrosarcoma. In addition, BPB also promoted cytosolic releases AIF and Endo G. Furthermore, it triggered extrinsic death receptor-dependent pathway, which was characterized by activating Fas, FADD and caspase-8. Most importantly, animal studies revealed a dramatic 40% reduction in tumor volume after 21 days of treatment. Thus, BPB may be a novel anticancer agent for the treatment of chondrosarcoma.

  14. 5,6-Dimethoxybenzofuran-3-one Derivatives: a Novel Series of Dual Acetylcholinesterase/Butyrylcholinesterase Inhibitors Bearing Benzyl Pyridinium Moiety

    Directory of Open Access Journals (Sweden)

    Mohammad Abdollahi

    2013-02-01

    Full Text Available Several studies have been focused on design and synthesis of multi-target anti Alzheimer compounds. Utilizing of the dual Acetylcholinesterase/Butyrylcholinesterase inhibitors has gained more interest to treat the Alzheimer’s disease. As a part of a research program to find a novel drug for treating Alzheimer disease, we have previously reported 6-alkoxybenzofuranone derivatives as potent acetylcholinesterase inhibitors. In continuation of our work, we would like to report the synthesis of 5,6-dimethoxy benzofuranone derivatives bearing a benzyl pyridinium moiety as dual Acetylcholinesterase/Butyrylcholinesterase inhibitors.MethodsThe synthesis of target compounds was carried out using a conventional method. Bayer-Villiger oxidation of 3,4-dimethoxybenzaldehyde furnished 3,4-dimethoxyphenol. The reaction of 3,4-dimethoxyphenol with chloroacetonitrile followed by treatment with HCl solution and then ring closure yielded the 5,6-dimethoxy benzofuranone. Condensation of the later compound with pyridine-4-carboxaldehyde and subsequent reaction with different benzyl halides afforded target compounds. The biological activity was measured using standard Ellman’s method. Docking studies were performed to get better insight into interaction of compounds with receptor.ResultsThe in vitro anti acetylcholinesterase/butyrylcholinesterase activity of compounds revealed that, all of the target compounds have good inhibitory activity against both Acetylcholinesterase/Butyrylcholinesterase enzymes in which compound 5b (IC50 = 52 ± 6.38nM was the most active compound against acetylcholinesterase. The same binding mode and interactions were observed for the reference drug donepezil and compound 5b in docking study.ConclusionsIn this study, we presented a new series of benzofuranone-based derivatives having pyridinium moiety as potent dual acting Acetylcholinesterase/Butyrylcholinesterase inhibitors.

  15. Unraveling the flavin-catalyzed photooxidation of benzylic alcohol with transient absorption spectroscopy from sub-pico- to microseconds.

    Science.gov (United States)

    Megerle, Uwe; Wenninger, Matthias; Kutta, Roger-Jan; Lechner, Robert; König, Burkhard; Dick, Bernhard; Riedle, Eberhard

    2011-05-21

    Flavin-mediated photooxidations have been described for applications in synthetic organic chemistry for some time and are claimed to be a route to the use of solar energy. We present a detailed investigation of the involved photophysical and photochemical steps in methoxybenzyl alcohol oxidation on a timescale ranging from sub-picoseconds to tens of microseconds. The results establish the flavin triplet state as the key intermediate for the photooxidation. The initial step is an electron transfer from the alcohol to the triplet state of the flavin catalyst with (3)k(ET)≈ 2 × 10(7) M(-1) s(-1), followed by a proton transfer in ∼6 μs. In contrast, the electron transfer involving the singlet state of flavin is a loss channel. It is followed by rapid charge recombination (τ = 50 ps) without significant product formation as seen when flavin is dissolved in pure benzylic alcohol. In dilute acetonitrile/water solutions of flavin and alcohol the electron transfer is mostly controlled by diffusion, though at high substrate concentrations >100 mM we also find a considerable contribution from preassociated flavin-alcohol-aggregates. The model including a productive triplet channel and a competing singlet loss channel is confirmed by the course of the photooxidation quantum yield as a function of substrate concentration: We find a maximum quantum yield of 3% at 25 mM of benzylic alcohol and significantly smaller values for both higher and lower alcohol concentrations. The observations indicate the importance to perform flavin photooxidations at optimized substrate concentrations to achieve high quantum efficiencies and provide directions for the design of flavin photocatalysts with improved performance.

  16. Analytical characterization of three hallucinogenic N-(2-methoxy)benzyl derivatives of the 2C-series of phenethylamine drugs.

    Science.gov (United States)

    Zuba, Dariusz; Sekuła, Karolina

    2013-08-01

    This publication reports analytical properties of three new hallucinogenic substances identified in blotter papers seized from the drug market, namely 25D-NBOMe [2-(2,5-dimethoxy-4-methylphenyl)-N-(2-methoxybenzyl)ethanamine], 25E-NBOMe [2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine] and 25G-NBOMe [2-(2,5-dimethoxy-3,4-dimethylphenyl)-N-(2-methoxybenzyl)ethanamine]. These substances are N-(2-methoxy)benzyl derivatives of the 2C-series of phenethylamine drugs. The applied procedure covered a variety of analytical methods, including gas chromatography with electron impact mass spectrometry (GC-EI-MS; without derivatization and after derivatization with trifluoroacetic anhydride (TFAA)), liquid chromatography-electrospray ionization-quadrupole time of flight mass spectrometry (LC-ESI-QTOF-MS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR), which made it possible to identify the active components unequivocally. The GC-MS spectra of analyzed compounds were very similar, with dominant ions observed at m/z = 150, 121, and 91. The remaining ions were analogous to those observed for parent substances, namely 2C-D, 2C-E, 2C-G, but their intensities were low. Derivatization allowed determination of molecular masses of the investigated substances. Their exact masses and chemical formulas were confirmed by LC-QTOF-MS experiments and the fragmentation patterns of these compounds following ESI were determined. The tandem mass spectrometry (MS/MS) experiments confirmed that the studied substances were N-(2-methoxy)benzyl derivatives of the 2C-series compounds. Final elucidation of the structures was performed by NMR spectroscopy. The substances were also characterized by FTIR spectroscopy to corroborate the identity of the compounds.

  17. How Radical is a Radical Innovation? An Outline for a Computational Approach

    NARCIS (Netherlands)

    Kasmire, J.; Korhonen, J.M.; Nikolic, I.

    2012-01-01

    Radical innovations prompt significant subsequent technological development and exhibit novelty and “architectural” innovation, i.e. rearranging the way design elements are put together in a system. Thus, radical innovations often serve as the foundation for new technological systems, industries or

  18. Environmentally persistent free radicals (EPFRs)-2. Are free hydroxyl radicals generated in aqueous solutions?

    Science.gov (United States)

    Khachatryan, Lavrent; Dellinger, Barry

    2011-11-01

    A chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed to measure the production of hydroxyl radical (·OH) in aqueous suspensions of 5% Cu(II)O/silica (3.9% Cu) particles containing environmentally persistent free radicals (EPFRs) of 2-monochlorophenol (2-MCP). The results indicate: (1) a significant differences in accumulated DMPO-OH adducts between EPFR containing particles and non-EPFR control samples, (2) a strong correlation between the concentration of DMPO-OH adducts and EPFRs per gram of particles, and (3) a slow, constant growth of DMPO-OH concentration over a period of days in solution containing 50 μg/mL EPFRs particles + DMPO (150 mM) + reagent balanced by 200 μL phosphate buffered (pH = 7.4) saline. However, failure to form secondary radicals using standard scavengers, such as ethanol, dimethylsulfoxide, sodium formate, and sodium azide, suggests free hydroxyl radicals may not have been generated in solution. This suggests surface-bound, rather than free, hydroxyl radicals were generated by a surface catalyzed-redox cycle involving both the EPFRs and Cu(II)O. Toxicological studies clearly indicate these bound free radicals promote various types of cardiovascular and pulmonary disease normally attributed to unbound free radicals; however, the exact chemical mechanism deserves further study in light of the implication of formation of bound, rather than free, hydroxyl radicals.

  19. Reactions of the tetraoxidosulfate(˙-) and hydroxyl radicals with poly(sodium α-methylstyrene sulfonate).

    Science.gov (United States)

    Dockheer, Sindy M; Gubler, Lorenz; Koppenol, Willem H

    2013-04-14

    Poly(α-methylstyrene sulfonic acid) (PAMS) represents a class of polymers that can form the protogenic constituent in electrolyte membranes for fuel cells. Oxidative stress is thought to play an important role in the degradation of the fuel cell membranes. Having previously established that damage may be mediated via abstraction of a benzylic hydrogen, we examined model compounds similar to those used before, but with a methyl group at the α-position. We studied the reaction of HO˙ and SO4(˙-), generated by pulse radiolysis, with model compounds in aqueous solution, and measured k = (2 ± 0.5) × 10(10) M(-1) s(-1) and (2 - 3) × 10(10) M(-1) s(-1) for the reaction of HO˙ with PAMS with average molecular weights of 2640 Da (PAMS-2640) and 6440 Da (PAMS-6440), respectively, at room temperature. At low pH, the decay of the hydroxycyclohexadienyl radical thus formed is accompanied by the formation of an absorption band in the visible region of the spectrum, which we tentatively assign to the radical cation of PAMS-2640 and -6440. The radical cation of PAMS-2640, formed by the reaction of SO4(˙-) with k = (6 ± 1) × 10(8) M(-1) s(-1), has a local absorption maximum at 560 nm, with ε560 ≥ 1400 M(-1) cm(-1). For the reaction of HO˙ and SO4(˙-) with the model compound benzenesulfonate, we measured k = (4-5) × 10(9) M(-1) s(-1) and (1.0 ± 0.3) × 10(8) M(-1) s(-1), respectively, while the reaction of SO4(˙-) with PAMS-6440 proceeds with (0.8-1) × 10(9) M(-1) s(-1). The 4-sulfophenoxyl radical was generated via the reaction of N3˙ with 4-hydroxybenzenesulfonate; ε410 ≥ 2300 M(-1) cm(-1). Not unexpectedly, the radical cation of PAMS is longer-lived than that of polystyrene sulfonic acid. Furthermore, fragmentation may result in desulfonation.

  20. Modeling Radicalization Phenomena in Heterogeneous Populations

    Science.gov (United States)

    2016-01-01

    The phenomenon of radicalization is investigated within a mixed population composed of core and sensitive subpopulations. The latest includes first to third generation immigrants. Respective ways of life may be partially incompatible. In case of a conflict core agents behave as inflexible about the issue. In contrast, sensitive agents can decide either to live peacefully adjusting their way of life to the core one, or to oppose it with eventually joining violent activities. The interplay dynamics between peaceful and opponent sensitive agents is driven by pairwise interactions. These interactions occur both within the sensitive population and by mixing with core agents. The update process is monitored using a Lotka-Volterra-like Ordinary Differential Equation. Given an initial tiny minority of opponents that coexist with both inflexible and peaceful agents, we investigate implications on the emergence of radicalization. Opponents try to turn peaceful agents to opponents driving radicalization. However, inflexible core agents may step in to bring back opponents to a peaceful choice thus weakening the phenomenon. The required minimum individual core involvement to actually curb radicalization is calculated. It is found to be a function of both the majority or minority status of the sensitive subpopulation with respect to the core subpopulation and the degree of activeness of opponents. The results highlight the instrumental role core agents can have to hinder radicalization within the sensitive subpopulation. Some hints are outlined to favor novel public policies towards social integration. PMID:27166677

  1. Modeling Radicalization Phenomena in Heterogeneous Populations.

    Directory of Open Access Journals (Sweden)

    Serge Galam

    Full Text Available The phenomenon of radicalization is investigated within a mixed population composed of core and sensitive subpopulations. The latest includes first to third generation immigrants. Respective ways of life may be partially incompatible. In case of a conflict core agents behave as inflexible about the issue. In contrast, sensitive agents can decide either to live peacefully adjusting their way of life to the core one, or to oppose it with eventually joining violent activities. The interplay dynamics between peaceful and opponent sensitive agents is driven by pairwise interactions. These interactions occur both within the sensitive population and by mixing with core agents. The update process is monitored using a Lotka-Volterra-like Ordinary Differential Equation. Given an initial tiny minority of opponents that coexist with both inflexible and peaceful agents, we investigate implications on the emergence of radicalization. Opponents try to turn peaceful agents to opponents driving radicalization. However, inflexible core agents may step in to bring back opponents to a peaceful choice thus weakening the phenomenon. The required minimum individual core involvement to actually curb radicalization is calculated. It is found to be a function of both the majority or minority status of the sensitive subpopulation with respect to the core subpopulation and the degree of activeness of opponents. The results highlight the instrumental role core agents can have to hinder radicalization within the sensitive subpopulation. Some hints are outlined to favor novel public policies towards social integration.

  2. High-Power-Density Organic Radical Batteries.

    Science.gov (United States)

    Friebe, Christian; Schubert, Ulrich S

    2017-02-01

    Batteries that are based on organic radical compounds possess superior charging times and discharging power capability in comparison to established electrochemical energy-storage technologies. They do not rely on metals and, hence, feature a favorable environmental impact. They furthermore offer the possibility of roll-to-roll processing through the use of different printing techniques, which enables the cost-efficient fabrication of mechanically flexible devices. In this review, organic radical batteries are presented with the focus on the hitherto developed materials and the key properties thereof, e.g., voltage, capacity, and cycle life. Furthermore, basic information, such as significant characteristics, housing approaches, and applied additives, are presented and discussed in the context of organic radical batteries.

  3. Exploring How Lead Users Develop Radical Innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher; Hienerth, Christoph; Gemuenden, Hans Georg

    2008-01-01

    In this study, we explore how lead users develop radical innovations outside of manufacturing firms. We analyze the transition from a very early stage of activities to the ultimate commercialization of these innovations. The focus in this context is on the initiatives undertaken by lead users...... lead users as surgeons launch entrepreneurial activities and bridge periods in which established medical equipment manufacturers would not risk investing in radical innovations. By doing so, lead users create the conditions usually provided in manufacturer-initiated lead user projects, including...... the supply of diversified knowledge, the development and coordination of a network for further development of the innovation, and initial tests of technical or market feasibility. Our findings have implications for manufacturing firms that wish to design radical innovation projects with (individual) lead...

  4. Resveratrol products resulting by free radical attack

    Science.gov (United States)

    Bader, Yvonne; Quint, R. M.; Getoff, Nikola

    2008-06-01

    Trans-resveratrol ( trans-3,4',5-trihydroxystilbene; RES), which is contained in red wine and many plants, is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. Among other duties, RES has been reported to have anti-carcinogenetic activities, which could be attributed to its antioxidant properties. The degradation of RES was studied under various conditions. The products (aldehydes, carboxylic acids, etc.) generated from RES by the attack of free radicals were registered as a function of the radical concentration (absorbed radiation dose). Based on the obtained data it appears that the OH radicals are initiating the rather complicated process, which involves of the numerous consecutive reactions. A possible starting reaction mechanism is presented.

  5. Resveratrol products resulting by free radical attack

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Yvonne; Quint, R.M. [Section Radiation Biology, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, UZAII, Althanstrasse 14, A-1090 Vienna (Austria); Getoff, Nikola [Section Radiation Biology, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, UZAII, Althanstrasse 14, A-1090 Vienna (Austria)], E-mail: nikola.getoff@univie.ac.at

    2008-06-15

    Trans-resveratrol (trans-3,4',5-trihydroxystilbene; RES), which is contained in red wine and many plants, is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. Among other duties, RES has been reported to have anti-carcinogenetic activities, which could be attributed to its antioxidant properties. The degradation of RES was studied under various conditions. The products (aldehydes, carboxylic acids, etc.) generated from RES by the attack of free radicals were registered as a function of the radical concentration (absorbed radiation dose). Based on the obtained data it appears that the OH radicals are initiating the rather complicated process, which involves of the numerous consecutive reactions. A possible starting reaction mechanism is presented.

  6. A Radically Configurable Six-State Compound

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J.C.; Fahrenbach, Albert C.; Cao, Dennis; Dyar, Scott M.; Frasconi, M.; Giesener, M. A.; Benítez, D.; Tkatchouk, E.; Li, H.; Stern, Charlotte L.; Sarjeant, Amy A.; Hartlieb, K.J.; Liu, Z.; Carmieli, Raanan; Botros, Y.Y.; Wasielewski, M. R.; Goddard III, W.A.; Stoddart, J. Fraser

    2013-01-24

    Most organic radicals possess short lifetimes and quickly undergo dimerization or oxidation. Here, we report on the synthesis by radical templation of a class of air- and water-stable organic radicals, trapped within a homo[2]catenane composed of two rigid and fixed cyclobis(paraquat-p-phenylene) rings. The highly energetic octacationic homo[2]catenane, which is capable of accepting up to eight electrons, can be configured reversibly, both chemically and electrochemically, between each one of six experimentally accessible redox states (0, 2+, 4+, 6+, 7+, and 8+) from within the total of nine states evaluated by quantum mechanical methods. All six of the observable redox states have been identified by electrochemical techniques, three (4+, 6+, and 7+) have been characterized by x-ray crystallography, four (4+, 6+, 7+, and 8+) by electron paramagnetic resonance spectroscopy, one (7+) by superconducting quantum interference device magnetometry, and one (8+) by nuclear magnetic resonance spectroscopy.

  7. Free radicals, antioxidant defense systems, and schizophrenia.

    Science.gov (United States)

    Wu, Jing Qin; Kosten, Thomas R; Zhang, Xiang Yang

    2013-10-01

    The etiopathogenic mechanisms of schizophrenia are to date unknown, although several hypotheses have been suggested. Accumulating evidence suggests that excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased production of reactive oxygen or decreased antioxidant protection in schizophrenic patients. This review aims to summarize the basic molecular mechanisms of free radical metabolism, the impaired antioxidant defense system and membrane pathology in schizophrenia, their interrelationships with the characteristic clinical symptoms and the implications for antipsychotic treatments. In schizophrenia, there is accumulating evidence of altered antioxidant enzyme activities and increased levels of lipid peroxidation, as well as altered levels of plasma antioxidants. Moreover, free radical-mediated abnormalities may contribute to specific aspects of schizophrenic symptomatology and complications of its treatment with antipsychotic drugs, as well as the development of tardive dyskinesia (TD). Finally, the potential therapeutic strategies implicated by the accumulating data on oxidative stress mechanisms for the treatment of schizophrenia are discussed.

  8. Elementary reaction allyl radical with oxygen

    Institute of Scientific and Technical Information of China (English)

    DONG Feng; KONG Fanao

    2003-01-01

    The elementary reaction between allyl radical with oxygen molecule wasexperimentally investigated. The allyl radical was produced via laser photolysis of C3H5Br in gaseous phase. Nascent vibrational excited products HCO, CO2, CH3CHO and HCOOH were recorded by the time- resolved Fourier transform infrared spectroscopy. The product channels of C2H5+CO2, CH3CHO+HCO, and HCOOH + C2H3 have been identified. The vibrational populations of product CO2 are obtained by spectral simulation. A mechanism forming a series of three-membered ring-struc- ture intermediates is suggested.

  9. Update on Robotic Laparoscopic Radical Prostatectomy

    Directory of Open Access Journals (Sweden)

    Garrett S. Matsunaga

    2006-01-01

    Full Text Available The da Vinci surgical robot has been shown to help shorten the learning curve for laparoscopic radical prostatectomy (LRP for both laparoscopically skilled and na surgeons[1,2]. This approach has shown equal or superior outcomes to conventional laparoscopic prostatectomy with regard to ease of learning, initial complication rates, conversion to open, blood loss, complications, continence, potency, and margin rates. Although the data are immature to compare oncologic and functional outcomes to open prostatectomy, preliminary data are promising.Herein, we review the technique and outcomes of robotic-assisted laparoscopic radical prostatectomy (RALP.

  10. Radical Islamism and Migrant Integration in Denmark

    DEFF Research Database (Denmark)

    Goli, Marco; Rezaei, Shahamak

    2011-01-01

    It has been suggested that alienation and failed integration may be causes of “Homegrown Radical Islamism” in Western societies. Western countries often expect that migrants and their descendants residing there as citizens will embrace or support common democratic ideals as a predicate for – or c......It has been suggested that alienation and failed integration may be causes of “Homegrown Radical Islamism” in Western societies. Western countries often expect that migrants and their descendants residing there as citizens will embrace or support common democratic ideals as a predicate...

  11. Resonance ionization detection of combustion radicals

    Energy Technology Data Exchange (ETDEWEB)

    Cool, T.A. [Cornell Univ., Ithaca, NY (United States)

    1993-12-01

    Fundamental research on the combustion of halogenated organic compounds with emphasis on reaction pathways leading to the formation of chlorinated aromatic compounds and the development of continuous emission monitoring methods will assist in DOE efforts in the management and disposal of hazardous chemical wastes. Selective laser ionization techniques are used in this laboratory for the measurement of concentration profiles of radical intermediates in the combustion of chlorinated hydrocarbon flames. A new ultrasensitive detection technique, made possible with the advent of tunable VUV laser sources, enables the selective near-threshold photoionization of all radical intermediates in premixed hydrocarbon and chlorinated hydrocarbon flames.

  12. Competing with the radical right. Distances between the European radical right and other parties on typical radical right issues

    NARCIS (Netherlands)

    Immerzeel, T.; Lubbers, M.; Coffe, H.R.

    2015-01-01

    The popularity of European Radical Right Populist parties (RRPs) has led to investigations into the distances between RRPs’ and other parties’ stances regarding immigration. This article adds to this literature by investigating the distance between RRPs and the other parties on a wider variety of ty

  13. Peroxy Radical Chemistry and Partitioning under a Ponderosa Pine Canopy

    Science.gov (United States)

    Wolfe, G. M.; Cantrell, C. A.; Mauldin, L.; Kim, S.; Henry, S. B.; Boyle, E. S.; Karl, T.; Harley, P. C.; Turnipseed, A.; Zheng, W.; Flocke, F. M.; Apel, E. C.; Hornbrook, R. S.; Hall, S. R.; Ullmann, K.; Guenther, A. B.; DiGangi, J. P.; Kaser, L.; Schnitzhofer, R.; Hansel, A.; Graus, M.; Nakashima, Y.; Kajii, Y. J.; Keutsch, F. N.

    2012-12-01

    As the first intermediates in the OH-initiated oxidation of hydrocarbons, peroxy radicals are central to the photochemistry of the lower atmosphere. Peroxy radical abundance and partitioning controls relative rates of radical propagation and termination in low-NOx regimes, and the coupled cycling of these molecules lies at the heart of recently-highlighted deficiencies in traditional chemical mechanisms. Using observations of hydroperoxy (HO2) and total peroxy (HO2 + RO2) radicals acquired during the summer 2010 BEACHON-ROCs campaign, we explore the processes affecting radical-mediated chemistry within a rural Ponderosa pine forest in central Colorado. Steady-state and fully-coupled 0-D modeling studies are used to provide complementary perspectives on our understanding of the radical budget in this environment. Analysis will focus on the nature and impact of unidentified radical sources and sinks and on how the composition of the peroxy radical pool modulates radical regeneration.

  14. Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

    Directory of Open Access Journals (Sweden)

    Béla Fiser

    Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

  15. Synthesis & Bio-Evaluation of 4-Amino-5-Benzyl-2, 4-Dihydro- 3H-1, 2, 4-Triazole-3-Thione Capped Silver Nano Particles

    Directory of Open Access Journals (Sweden)

    M. Padma

    2015-02-01

    Full Text Available Synthesis of 4-amino-5-benzyl-2,4-dihydro-3H-1,2,4-triazole-3-thione Capped Silver NanoParticles by a simple procedure. Spherical shaped Capped Ag-NPs with average size of 14.65 nm are obtained by the treatment of aqueous silver ions with hot ethanolic solution of 4-amino-5-benzyl-2,4-dihydro-3H-1,2,4-triazole-3-thione as Stabilizing/Reducing agent. The Nanoparticles are characterized using TEM, XRD and FTIR studies. The synthesized Nanoparticles were tested for in vitro antimicrobial activity at concentrations of 50, 100, 200 μg /ml. The Nanoparticles showed good activity, nearly equal to the inhibition zone value of ciprofloxacin, against the E.coli bacteria. For the antifungal activity, the compound showed equipotent activity against A.niger.

  16. Development of 3-methoxy-4-benzyloxybenzyl alcohol (MBBA) resin as polymer-supported synthesis support: Preparation and benzyl ether cleavage by DDQ oxidation

    Indian Academy of Sciences (India)

    Qiang Huang; Bao-Zhong Zheng; Quan Long

    2010-03-01

    3-Methoxy-4-benzyloxybenzyl alcohol (MBBA) resin was synthesized by a two-step sequence under microwave irradiation involving the reaction of commercially available Merrifield resin with vanillin, followed by reduction with sodium borohydride. MBBA resin was treated with bromides in the presence of sodium hydride to afford the corresponding resin-bound benzyl ethers. Cleavage of the resin-bound benzyl ethers from the MBBA resin was carried out using 2,3-dichloro-5,6-dicyanobenzoqunone (DDQ) to give the corresponding alcohols in good yields. Moreover, the recovery, regeneration, and reuse of this polymer support could be achieved easily. MBBA resin can be developed as a kind of solid-phase synthesis bead of alcohols.

  17. Ecotoxicological evaluation of the biocidal agents sodium o-phenylphenol, sodium o-benzyl-p-chlorophenol, and sodium p-tertiary amylphenol.

    Science.gov (United States)

    Davoren, M; Fogarty, A M

    2005-02-01

    The ecotoxicological effects of three biocidal agents frequently employed as active ingredients in phenolic-based disinfectants were evaluated using a test battery comprising of organisms representing three aquatic trophic levels. Phenolic-based disinfectants are commonly used by mushroom growers to disinfect spent mushroom compost. In general, the most sensitive assay used in this study was the Microtox test. In the case of the fish lethality assay, sodium o-benzyl-p-chlorophenol was found to be slightly more sensitive than the bacterial test system. The freshwater alga and invertebrate tests were also among the most sensitive test species employed. The active ingredient, sodium o-benzyl-p-chlorophenol (with the exception of the Microtox assay), was the most toxic chemical tested on each species. The majority of ecotoxicity data obtained in this research has not been previously reported and may therefore assist in the management and planning decisions regarding the application of pesticides and utilisation of SMC.

  18. Synthesis and activity of (R)-(-)-m-trimethylacetoxy-alpha-[(methylamino)methyl]benzyl alcohol hydrochloride: a prodrug form of (R)-(-)-phenylephrine.

    Science.gov (United States)

    Yuan, S S; Bador, N

    1976-06-01

    Optically pure (R)-(-)-m-trimethylacetoxy-alpha-[(methylamino)methyl]benzyl alcohol hydrochloride was synthesized by the following sequence: (R)-(-)-phenylephrine was condensed with acetone in the presence of calcium carbide to give an oxazolidine derivative and then treated with thallous ethoxide in ether followed by trimethylacetyl chloride to yield the phenolic ester. Finally, the oxazolidine ring was cleaved by one equivalent of hydrogen chloride in ethanol. Condensation of phenylephrine with benzaldehyde, with or without solvents, gave either 1,1,2-trimethyl-4,6-dihydroxy-1,2,3,4-tetrahydroisoquinoline or a mixture of side-chain oxazolidine and the tetrahydroisoquinoline. Condensation of epinephrine with opianic acid in pyridine also gave a tetrahydroisoquinoline only. When applied on rabbit eyes, the prodrug (R)-(-)-m-trimethylacetoxy-alpha[(methylamino)methyl]benzyl alcohol hydrochloride exhibited an unexpected, three times higher mydriatic activity than the corresponding racemic prodrug and was 15 times more active than the parent, (R)-(-)-phenylephrine.

  19. Radical Negativity: Music Education for Social Justice

    Science.gov (United States)

    McLaren, Peter

    2011-01-01

    According to Hedges (2010), the real enemies of the liberal class are radical thinkers such as Noam Chomsky and Ralph Nader, iconoclastic intellectuals who possess the moral autonomy to defy the power elite. While this author agrees with Hedges, he would take this argument even further. In this article, the author argues that the real enemy of…

  20. Serendipitous findings while researching oxygen free radicals.

    Science.gov (United States)

    Floyd, Robert A

    2009-04-15

    This review is based on the honor of receiving the Discovery Award from the Society of Free Radical Biology and Medicine. The review is reflective and presents our thinking that led to experiments that yielded novel observations. Critical questioning of our understanding of oxygen free radicals in biomedical problems led us to use and develop more direct and extremely sensitive methods. This included nitrone free radical spin trapping and HPLC-electrochemical detection. This technology led to the pioneering use of salicylate to trap hydroxyl free radicals and show increased flux in ischemia/reperfused brain regions and also to first sensitively detect 8-hydroxyl-2-deoxyguanosine in oxidatively damaged DNA and help assess its role in cancer development. We demonstrated that methylene blue (MB) photoinduces formation of 8-hydroxyguanine in DNA and RNA and discovered that MB sensitively photoinactivates RNA viruses, including HIV and the West Nile virus. Studies in experimental stroke led us serendipitously to discover that alpha-phenyl-tert-butylnitrone (PBN) was neuroprotective if given after the stroke. This led to extensive commercial development of NXY-059, a PBN derivative, for the treatment of stroke. More recently we discovered that PBN nitrones have potent anti-cancer activity and are active in preventing hearing loss caused by acute acoustical trauma.

  1. Designed metalloprotein stabilizes a semiquinone radical

    Science.gov (United States)

    Ulas, Gözde; Lemmin, Thomas; Wu, Yibing; Gassner, George T.; Degrado, William F.

    2016-04-01

    Enzymes use binding energy to stabilize their substrates in high-energy states that are otherwise inaccessible at ambient temperature. Here we show that a de novo designed Zn(II) metalloprotein stabilizes a chemically reactive organic radical that is otherwise unstable in aqueous media. The protein binds tightly to and stabilizes the radical semiquinone form of 3,5-di-tert-butylcatechol. Solution NMR spectroscopy in conjunction with molecular dynamics simulations show that the substrate binds in the active site pocket where it is stabilized by metal-ligand interactions as well as by burial of its hydrophobic groups. Spectrochemical redox titrations show that the protein stabilized the semiquinone by reducing the electrochemical midpoint potential for its formation via the one-electron oxidation of the catechol by approximately 400 mV (9 kcal mol-1). Therefore, the inherent chemical properties of the radical were changed drastically by harnessing its binding energy to the metalloprotein. This model sets the basis for designed enzymes with radical cofactors to tackle challenging chemistry.

  2. Identity and Islamic Radicalization in Western Europe

    NARCIS (Netherlands)

    S.M. Murshed (Syed); S. Pavan (Sara)

    2009-01-01

    textabstractThis paper argues that both socio-economic disadvantage and political factors, such as the West’s foreign policy with regard to the Muslim world, along with historical grievances, play a part in the development of Islamic radicalized collective action in Western Europe. We emphasise the

  3. Albert Einstein: Radical Pacifist and Democrat

    Science.gov (United States)

    Jayaraman, T.

    We draw attention here to the radical political grounding of Einstein's pacifism. We also drescribe some less commonly known aspects of his commitment to civil liberties, particularly in the context of the anti-l hysteria and anti-racism current in the United States of the late 1940s and 1950s. We also examine briefly his views on socialism.

  4. Radical recombinations in acetylene-air flames

    NARCIS (Netherlands)

    Zeegers, P.J.Th.; Alkemade, C.T.J.

    1965-01-01

    In this paper an analysis is given of the behaviour of excess radical concentrations, H, OH and O as a function of height above the reaction zone in premixed acetylene-air flames at 2–200° to 2400°K and 1 atmosphere pressure. The intensity was measured of the Li resonance line which is related to th

  5. User involvement competence for radical innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher

    2007-01-01

    -assisted navigation systems. The case study analysis reveals that firms who closely interact with specific users benefit significantly for their radical innovation work. These users have a high motivation toward new solutions, are open to new technologies, possess diverse competencies, and are embedded into a very...

  6. Radical Welfare State Retrenchment: A Comparative Analysis

    DEFF Research Database (Denmark)

    Starke, Peter

    as electoral suicide, but this changed in the 1980s when Margaret Thatcher's government began a series of cutbacks in the UK. During the 1990s, the New Zealand government announced the most radical social benefit cutbacks the country had ever seen. Examining these cases in detail, and contrasting them...

  7. Radical Change: Digital Age Literature and Learning.

    Science.gov (United States)

    Dresang, Eliza T.; McClelland, Kathryn

    1999-01-01

    Describes the concept of radical change, a theoretical construct that identifies and explains books with characteristics reflecting the types of interactivity, connectivity, and access that permeate the emerging digital society. Highlights innovative ways that authors, illustrators, and designers incorporate these features into books for…

  8. Customers as Partners in Radical Service Innovation

    DEFF Research Database (Denmark)

    Scupola, Ada; Nicolajsen, Hanne Westh

    2009-01-01

      Purpose- The main purpose of this paper is to investigate customer involvement and related challenges in radical service innovations in engineering consulting services Design/methodology/approach - The paper uses a case study approach and so called rich descriptions to investigate customer invo...

  9. Free radicals in adolescent varicocele testis.

    Science.gov (United States)

    Romeo, Carmelo; Santoro, Giuseppe

    2014-01-01

    We examine the relationship between the structure and function of the testis and the oxidative and nitrosative stress, determined by an excessive production of free radicals and/or decreased availability of antioxidant defenses, which occur in the testis of adolescents affected by varicocele. Moreover, the effects of surgical treatment on oxidative stress were provided. We conducted a PubMed and Medline search between 1980 and 2014 using "adolescent," "varicocele," "free radicals," "oxidative and nitrosative stress," "testis," and "seminiferous tubules" as keywords. Cross-references were checked in each of the studies, and relevant articles were retrieved. We conclude that increased concentration of free radicals, generated by conditions of hypoxia, hyperthermia, and hormonal dysfunction observed in adolescent affected by varicocele, can harm germ cells directly or indirectly by influencing nonspermatogenic cells and basal lamina. With regard to few available data in current literature, further clinical trials on the pre- and postoperative ROS and RNS levels together with morphological studies of the cellular component of the testis are fundamental for complete comprehension of the role played by free radicals in the pathogenesis of adolescent varicocele and could justify its pharmacological treatment with antioxidants.

  10. 一种选择性脱苄基方法在天然产物结构修饰中的应用%Selective cleavage of benzyl group in structural modification of natural product

    Institute of Scientific and Technical Information of China (English)

    朱华; 张爱军; 崔庆彬; 谭子铖; 傅和亮; 于沛

    2012-01-01

    Objective To study the selectivity of the Lewis acid boron trifluoride diethyl etherate used in debenzylation. Methods Naturally active ingredients Danshensu. Ferulic acid and salicylic acid were used as the starting materials to synthesize compounds containing both benzyl ether and ester. Boron trifluoride diethyl etherate was chosen for the removal of benzyl protection. Results Only benzyl ether was cleaved by boron trifluoride diethyl etherate while the benzyl ester was not affected. Conclusion Benzyl ether has been selectively cleaved by boron trifluoride diethyl etherate with the present of benzyl ester in one molecule.%目的 研究路易斯酸三氟化硼乙醚在脱苄基时的选择性.方法 以天然活性成分丹参素、阿魏酸和水杨酸为原料,制备的化合物结构中既含有苄醚又含有苄酯,采用上述方法进行苄基保护的脱除.结果 三氟化硼乙醚只脱去苄醚上的苄基,而苄酯中的苄基不受影响.结论 三氟化硼乙醚在苄醚和苄酯同时存在的情况下,对苄醚上的苄基具有选择性脱除作用.

  11. Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L.; Leone, Stephen R.

    2009-12-23

    Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ~;; 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn?s moon Titan (~;;100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).

  12. Molecular modeling and experimental studies on structure and NMR parameters of 9-benzyl-3,6-diiodo-9H-carbazole

    DEFF Research Database (Denmark)

    Radula-Janik, Klaudia; Kupka, Teobald; Ejsmont, Krzysztof;

    2015-01-01

    A combined experimental and theoretical study has been performed on 9-benzyl-3,6-diiodo-9H-carbazole. Experimental X-ray (100.0 K) and room-temperature 13C NMR studies were supported by advanced density functional theory (DFT) calculations. The non relativistic structure optimization was performed.......57 ppm dropped to 5.6 ppm). A good linear correlation between experimental and theoretically predicted structural and NMR parameters was observed....

  13. Transition metal-free oxidation of benzylic alcohols to carbonyl compounds by hydrogen peroxide in the presence of acidic silica gel

    Directory of Open Access Journals (Sweden)

    Hossein Ghafuri

    2015-01-01

    Full Text Available Oxidation of alcohols to carbonyl compounds has become an important issue in the process industry as well as many other applications. In this method, various benzylic alcohols were successfully converted to corresponding aldehydes and ketones under transition metal-free condition using hydrogen peroxide in the presence of some amount of catalytic acidic silica gel. Silica gel is inexpensive and available. One of the most important features of this method is its short reaction time.

  14. Facile fabrication of magnetically recyclable metal-organic framework nanocomposites for highly efficient and selective catalytic oxidation of benzylic C-H bonds.

    Science.gov (United States)

    Chen, Yifa; Huang, Xianqiang; Feng, Xiao; Li, Jikun; Huang, Yingyu; Zhao, Jingshu; Guo, Yuexin; Dong, Xinmei; Han, Ruodan; Qi, Pengfei; Han, Yuzhen; Li, Haiwei; Hu, Changwen; Wang, Bo

    2014-08-07

    HKUST-1@Fe3O4 chemically bonded core-shell nanoparticles have been prepared by growing HKUST-1 thin layers joined by carboxyl groups onto Fe3O4 nanospheres. These magnetic core-shell MOF nanostructures show exceptional catalytic activity for the oxidation of benzylic C-H bonds and they can be recovered by magnetic separation and reused without losing any activity.

  15. 高剂量O-糖基化修饰抑制剂Benzyl-α-GalNAc诱导体外培养肝细胞脂肪变%Effect of O-Glycosylation Inhibitor,Benzyl-α-GalNAc,on Hepatocytes in vitro

    Institute of Scientific and Technical Information of China (English)

    张晓静; 张仁雯; 郝晓花; 任慧; 李红敏; 刘燃; 王智强; 魏红山

    2013-01-01

    目的 初步探讨蛋白质O-糖基化抑制剂Benzyl-α-GalNAc对肝细胞的影响.方法 取雌性Balb/c小鼠(8~10周)20只随机分为正常组(n =10),Benzyl-α-GalNAc药物组(n=10),给Benzyl-α-GalNAc药物(5 mg/kg,1次/d)灌胃.第2周末取小鼠血清及肝脏进行血清生化指标ALT及ALP测定及肝组织HE染色.培养HepG2细胞,Benzyl-α-GalNAc分别以0.5、1 及5 mg/ml与HepG2细胞共孵育.24 h后进行油红O染液染色.5 mg/ml药物组完全未贴壁,去除处理因素,继续培养12 h观察细胞.Benzyl-α-GalNAc以3 mg/ml处理HepG2细胞12 h及24 h观察细胞贴壁情况.培养L02细胞,Benzyl-α-GalNAc分别以0.1及0.5 mg/ml与L02细胞共孵育.24 h后进行油红O染液染色.结果 药物组与正常对照组比较,肝组织切片显示轻微脂肪变.油红O染色显示药物处理组HepG2及L02细胞内的脂滴积聚.高浓度组细胞完全没有贴壁,24 h后更换无药物培养基,去除处理因素12 h后,可见HepG2开始贴壁生长.结论 高浓度O-糖基化抑制剂Benzyl-α-GalNAc抑制体外肝细胞的黏附,并诱导轻微肝细胞脂肪变.

  16. L-天门冬氨酸-β-苄酯的制备研究%Synthesis and characterization of L-aspartic acid-β-benzyl ester

    Institute of Scientific and Technical Information of China (English)

    王昌济; 王永秋

    2013-01-01

    L-aspartic acid and benzyl alcohol as raw materials, studied on the synthesis of L-aspartic acid-/3-benzyl ester. The results showed that the best experimental conditions was; the concentrated sulfuric acid as catalyst,n (L-aspartic acid) : n (benzyl alcohol) = 1 : 10,100℃ reflux reaction 3 h,placed at room temperature 24 h, in this condition, the yield was about 60% .%以L-天门冬氨酸和苯甲醇为原料,对L-天门冬氨酸-β-苄酯的合成进行了研究.结果表明,较佳实验条件是:以浓硫酸为催化剂,n(L-天门冬氨酸)∶n(苯甲醇)=1∶10,100℃回流反应3h,室温放置24h,在该条件下,产率约60%.

  17. Sensitization and quenching in the conversion of light energy into chemical energy. Progress report, February 1, 1979-January 31, 1980. [Benzylic chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Cristol, S.J.

    1979-09-01

    Data have been accumulated on the rates of excitation transfer from acetone or acetophenone sensitizers to several benzylic chlorides in acetonitrile-t-butyl alcohol or acetone-t-butyl alcohol and on the lifetimes of the excited triplet intermediates leading to solvolysis products (arylmethyl t-butyl ethers and arylmethanols). Lifetimes were found to be in the 0-2 nsec range. In direct irradiation, in t-butyl alcohol or acetonitrile-t-butyl alcohol, t-butyl ethers are formed from intermediates which are either singlets or are triplets of short lifetimes (0-2 nsec). Long-lived triplets, which do not lead to t-butyl ethers or to other products, but which decay to starting materials, and which arise by intersystem crossing from excited singlet states, were discovered by their ability to isomerize cis-piperylene (Hammond-Lamola quenching). These hidden triplets were shown to be produced as well by excitation transfer from benzophenone. They represent a large fraction of the energy wastage in this system. Work has begun on the preparation of materials for study of optically active benzylic chloride solvolyses, for study of optically active benzylic chloride solvolyses, for study of intramolecular (2 + 2) cycloadditions and for di-..pi..-methane studies, in our attempts to understand the mechanistic details of these important photochemical reactions.

  18. Selective oxidation of benzyl alcohol with tert-butylhydroperoxide catalysed via Mn (II) 2, 2-bipyridine complexes immobilized over the mesoporous hexagonal molecular sieves (HMS)

    Indian Academy of Sciences (India)

    Vahid Mahdavi; Mahdieh Mardani

    2012-09-01

    A series ofMn(II)bipy complexes with different loading of Mn2+ supported on HMS was prepared. These samples were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Thermogravimetric and Differential Scanning Calorimetry (TG-DSC), Ultraviolet and Visible spectra (UV-Vis) and Fourier transforms Infrared (FT-IR). The catalytic activity of the supportedMn(II)bipy complexes, [Mn(bipy)2]2+/HMS was evaluated in the oxidation of benzyl alcohol in the liquid phase using tert-butylhydroperoxide (TBHP) as an oxidant. The effects of Mn2+ loading and various solvents on the conversion and selectivity were studied. A second order function for the variation in catalytic activity with respect to the loading of Mn2+ ions in different catalyst samples was observed. The activity of the [Mn(bipy)2]2+/HMS catalyst differs with the type of the solvent and in this case, acetonitrile gives the best conversion results. The kinetic of benzyl alcohol oxidation was investigated at temperatures of 27, 46, 60, 75 and 90°C using [Mn(bipy)2]2+/HMS and excess TBHP. The order of reaction with respect to benzyl alcohol was determined to be pseudo-first order. The value of the apparent activation energy was also determined.

  19. Plasmonic Au/CdMoO{sub 4} photocatalyst: Influence of surface plasmon resonance for selective photocatalytic oxidation of benzylic alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Bi, Jinhong, E-mail: bijinhong@fzu.edu.cn [Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108 (China); Research Institute of Photocatalysis, State Key Laboratory Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, Fujian 350002 (China); Zhou, Zhiyong; Chen, Mengying [Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108 (China); Liang, Shijing [Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian 350108 (China); Research Institute of Photocatalysis, State Key Laboratory Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, Fujian 350002 (China); He, Yunhui; Zhang, Zizhong [Research Institute of Photocatalysis, State Key Laboratory Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, Fujian 350002 (China); Wu, Ling, E-mail: wuling@fzu.edu.cn [Research Institute of Photocatalysis, State Key Laboratory Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, Fujian 350002 (China)

    2015-09-15

    Graphical abstract: - Highlights: • Au/CdMoO{sub 4} composites were constructed for the first time. • Au/CdMoO{sub 4} showed superior activity for selective oxidation of benzylic alcohol. • The visible light photocatalytic activity is ascribed to the SPR effect of Au. - Abstract: Novel visible-light-driven plasmonic Au/CdMoO{sub 4} photocatalysts were synthesized by hydrothermal process following chemical reduction process. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The results show the catalysts exhibited strong visible light absorption due to the surface plasmon resonance effect of Au nanoparticles. Compared to CdMoO{sub 4}, Au/CdMoO{sub 4} composites displayed superior photocatalytic activities for the selective oxidation of benzylic alcohol to benzaldehyde under visible light. The highest conversion was obtain by the 1.6% Au loaded CdMoO{sub 4}. The mechanism for the selective oxidation of benzylic alcohol in the Au/CdMoO{sub 4} system is proposed.

  20. The Benzyl Ester Group of Amino Acid Monomers Enhances Substrate Affinity and Broadens the Substrate Specificity of the Enzyme Catalyst in Chemoenzymatic Copolymerization.

    Science.gov (United States)

    Ageitos, Jose Manuel; Yazawa, Kenjiro; Tateishi, Ayaka; Tsuchiya, Kousuke; Numata, Keiji

    2016-01-11

    The chemoenzymatic polymerization of amino acid monomers by proteases involves a two-step reaction: the formation of a covalent acyl-intermediate complex between the protease and the carboxyl ester group of the monomer and the subsequent deacylation of the complex by aminolysis to form a peptide bond. Although the initiation with the ester group of the monomer is an important step, the influence of the ester group on the polymerization has not been studied in detail. Herein, we studied the effect of the ester groups (methyl, ethyl, benzyl, and tert-butyl esters) of alanine and glycine on the synthesis of peptides using papain as the catalyst. Alanine and glycine were selected as monomers because of their substantially different affinities toward papain. The efficiency of the polymerization of alanine and glycine benzyl esters was much greater than that of the other esters. The benzyl ester group therefore allowed papain to equally polymerize alanine and glycine, even though the affinity of alanine toward papain is substantially higher. The characterization of the copolymers of alanine and glycine in terms of the secondary structure and thermal properties revealed that the thermal stability of the peptides depends on the amino acid composition and resultant secondary structure. The current results indicate that the nature of the ester group drastically affects the polymerization efficiency and broadens the substrate specificity of the protease.

  1. SYNTHESIS AND CHARACTERIZATION OF POLY(AMINO ACID-UREA)S COMPRISING NOVEL TRIBLOCK COPOLYMERS OF POLY(TETRAHYDROFURAN) AND POLY(γ-BENZYL L-GLUTAMATE)S

    Institute of Scientific and Technical Information of China (English)

    Hai-bin Li; Zhen Tian; Ai-ying Zhang; Zeng-guo Feng

    2009-01-01

    A kind of novel triblock copolymers of poly(y:benzyl L-glutamate)-b-poly(tetrahydrofuran)-b-poly(γ-benzyl L-glutamate)s (PBLG-b-PTHF-b-PBLG) was synthesized by using bis(3-aminopropyl) terminated polytetrahydrofuran to initiate the ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride (BLG-NCA). The corresponding multiblock poly(amino aeid-urea)s were prepared in one-pot protocol from the chain extension of PBLG-b-PTHF-b-PBLG with MDI. The resulting triblock and multiblock copolymers were characterized by FFIR, 1H-NMR, 13C-NMR and GPC techniques. It is demonstrated that the chain extension has taken place to give rise to the copolymers with the well-defined block composition and narrow molecular weight distribution. A distinct Tg arising from the hard-segments was observed in all the copolymers. Their mechanical properties showed an increasing trend with the molecular weight enhancement of the prepolymers.

  2. Real-Time Detection of Traces of Benzaldehyde in Benzyl Alcohol as a Solvent by a Flexible Lanthanide Microporous Metal-Organic Framework.

    Science.gov (United States)

    Zhang, Huan; Chen, Diming; Ma, Huili; Cheng, Peng

    2015-10-26

    Luminescent 3D lanthanide metal-organic framework (Ln-MOF) {[Tb2 (TATAB)2 ]⋅4 H2 O⋅6 DMF}n (1) was synthesized under solvothermal conditions by using flexible ligand 4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB). A phase transition was observed between low temperature and room temperature. The luminescence of 1 could be enhanced by formaldehyde and quenched efficiently by trace amounts of benzaldehyde in solvents such as benzyl alcohol (0.01-2.0 vol %) and ethanol (0.01-2.5 vol %). This is the first use of a Ln-MOF as chemical sensor for both formaldehyde and benzaldehyde. The high sensitivity and selectivity of the luminescence response of 1 to benzaldehyde allows it to be used as an excellent sensor for identifying benzaldehyde and provides a simple and convenient method for detecting traces of benzaldehyde in benzyl alcohol based injections. This work establishes a new strategy for detection of benzaldehyde in benzyl alcohol by luminescent MOFs.

  3. A comparative study of silver-graphene oxide nanocomposites as a recyclable catalyst for the aerobic oxidation of benzyl alcohol: Support effect

    Energy Technology Data Exchange (ETDEWEB)

    Zahed, Bahareh; Hosseini-Monfared, Hassan, E-mail: monfared@znu.ac.ir

    2015-02-15

    Graphical abstract: - Highlights: • Characteristics of three different graphene oxide (GO) are studied as a support for Ag nanoparticles. • The required conditions for a best support are determined. • For the first time the silver nanoparticles decorated GO as catalyst for aerobic oxidation of benzyl alcohol and the effects of the degree of reduction of GO on AgNPs on GO are reported. - Abstract: Three different nanocomposites of silver and graphene oxide, namely silver nanoparticles (AgNPs) immobilized on reduced graphene oxide (AgNPs/rGO), partially reduced graphene oxide (AgNPs/GO) and thiolated partially reduced graphene oxide (AgNPs/GOSH), were synthesized in order to compare their properties. Characterizations were carried out by infrared and UV–Vis and Raman spectroscopy, ICP, X-ray diffraction, SEM and TEM, confirming both the targeted chemical modification and the composite formation. The nanocomposites were successfully employed in the aerobic oxidation of benzyl alcohol at atmospheric pressure. AgNPs/GOSH is stable and recyclable catalyst which showed the highest activity in the aerobic oxidation of benzyl alcohol in the presence of N-hydroxyphthalimide (NHPI) to give benzaldehyde with 58% selectivity in 24 h at 61% conversion. The favorite properties of AgNPs/GOSH are reasonably attributed to the stable and well distributed AgNPs over GOSH due to strong adhesion between AgNPs and GOSH.

  4. Radical scavenging activity of antioxidants evaluated by means of electrogenerated HO radical.

    Science.gov (United States)

    Oliveira, Raquel; Geraldo, Dulce; Bento, Fátima

    2014-11-01

    A method is proposed and tested concerning the characterization of antioxidants by means of their reaction with electrogenerated HO radicals in galvanostatic assays with simultaneous O2 evolution, using a Pt anode fairly oxidized. The consumption of a set of species with antioxidant activity, ascorbic acid (AA), caffeic acid (CA), gallic acid (GA) and trolox (T), is described by a first order kinetics. The rate of the processes is limited by the kinetics of reaction with HO radicals and by the kinetics of charge transfer. Information regarding the scavenger activity of antioxidants is obtained by the relative value of the rate constant of the reaction between antioxidants and HO radicals, k(AO,HO)/k(O2). The number of HO radicals scavenged per molecule of antioxidant is also estimated and ranged from 260 (ascorbic acid) to 500 (gallic acid). The method is applied successfully in the characterization of the scavenger activity of ascorbic acid in a green-tea based beverage.

  5. Pressure effects on the radical-radical recombination reaction of photochromic bridged imidazole dimers.

    Science.gov (United States)

    Mutoh, Katsuya; Abe, Jiro

    2014-09-07

    The bridged imidazole dimers are some of the attractive fast photochromic compounds which have potential applications to the ophthalmic lenses, real-time hologram and molecular machines. The strategy for expanding their photochromic properties such as the colour variation and tuning the decolouration rates has been vigorously investigated, but the insight into the structural changes along the photochromic reactions has not been demonstrated in detail. Here, we demonstrated the pressure dependence of the radical-radical recombination reaction of the bridged imidazole dimers. The radical-radical interaction can be controlled by applying high pressure. Our results give fundamental information about the molecular dynamics of the bridged imidazole dimers, leading to the development of new functional photochromic machines and pressure-sensitive photochromic materials.

  6. Charge transfer from 2-aminopurine radical cation and radical anion to nucleobases: A pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Manoj, P. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Mohan, H. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mittal, J.P. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Manoj, V.M. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Aravindakumar, C.T. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India)], E-mail: CT-Aravindakumar@rocketmail.com

    2007-01-08

    Pulse radiolysis study has been carried out to investigate the properties of the radical cation of 2-aminopurine (2AP) and the probable charge transfer from the radical cation and radical anion of 2AP to natural nucleobases in aqueous medium. The radical cation of 2AP was produced by the reaction of sulfate radical anion (SO{sub 4}{sup dot-}). The time resolved absorption spectra obtained by the reaction of SO{sub 4}{sup dot-} with 2AP at neutral pH have two distinct maxima at 380 and 470nm and is assigned to the formation of a neutral radical of the form 2AP-N{sup 2}(-H){sup dot} (k{sub 2}=4.7x10{sup 9}dm{sup 3}mol{sup -1}s{sup -1} at pH 7). This neutral radical is formed from the deprotonation reaction of a very short-lived radical cation of 2AP. The transient absorption spectra recorded at pH 10.2 have two distinct maxima at 400 and 480nm and is assigned to the formation of a nitrogen centered radical (2AP-N(9){sup dot}). As the hole transport from 2AP to guanine is a highly probable process, the reaction of SO{sub 4}{sup dot-} is carried out in the presence of guanosine, adenosine and inosine. The spectrum obtained in the presence of guanosine was significantly different from that in the absence and it showed prominent absorption maxima at 380 and 470nm, and a weak broad maximum centered around 625nm which match well with the reported spectrum of a neutral guanine radical (G(-H){sup dot}). The electron transfer reaction from the radical anion of 2AP to thymine (T), cytidine (Cyd) and uridine (Urd) was also investigated at neutral pH. Among the three pyrimidines, only the transient spectrum in the presence of T gave a significant difference from the spectral features of the electron adduct of 2AP, which showed a prominent absorption maximum at 340nm and this spectrum is similar to the electron adduct spectrum of T. The preferential reduction of thymine by 2AP{sup dot-} and the oxidation of guanosine by 2AP{sup dot+} clearly follow the oxidation

  7. The Reaction Kinetics of Neutral Free Radicals and Radical Ions Studied by Laser Flash Photolysis

    OpenAIRE

    Friedline, Robert Alan

    2004-01-01

    t-Butoxyl radical has been used as a chemical model for hydrogen abstractions in many enzymatic and biological systems. However, the question has arisen as to how well this reactive intermediate mimics these systems. In addressing this concern, absolute rate constants and Arrhenius parameters for hydrogen abstraction by t-butoxyl radical were measured for a broad class of substrates including amines, hydrocarbons, and alcohols using laser flash photolysis. Initially, no obvious reactivity ...

  8. Evaluation of the radical scavenging activity of a series of synthetic hydroxychalcones towards the DPPH radical

    Directory of Open Access Journals (Sweden)

    STOYAN P. PARUSHEV

    2011-04-01

    Full Text Available Sixteen hydroxychalcones were synthesized in sufficient purity by the Claisen–Schmidt condensation between appropriate acetophenones and aromatic aldehydes. All the compounds were evaluated for their ability to scavenge the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH radical. Important structure–activity relationships were observed that strongly contribute to the knowledge for the design of DPPH radical scavenging chalcones. Relevant theoretical parameters were computed in an attempt to understand and explain the obtained experimental results.

  9. Nature of the lowest excited states of neutral polyenyl radicals and polyene radical cations

    Science.gov (United States)

    Starcke, Jan Hendrik; Wormit, Michael; Dreuw, Andreas

    2009-10-01

    Due to the close relation of the polyenyl radicals C2n+1H2n+3• and polyene radical cations C2nH2n+2•+ to the neutral linear polyenes, one may suspect their excited states to possess substantial double excitation character, similar to the famous S1 state of neutral polyenes and thus to be equally problematic for simple excited state theories. Using the recently developed unrestricted algebraic-diagrammatic construction scheme of second order perturbation theory and the equation-of-motion coupled-cluster method, the vertical excitation energies, their corresponding oscillator strengths, and the nature of the wave functions of the lowest excited electronic states of the radicals are calculated and analyzed in detail. For the polyenyl radicals two one-photon allowed states are found as D1 and D4 states, with two symmetry-forbidden D2 and D3 states in between, while in the polyene radical cations D1 and D2 are allowed and D3 is forbidden. The order of the states is conserved with increasing chain length. It is found that all low-lying excited states exhibit a significant but similar amount of doubly excited configuration in their wave functions of 15%-20%. Using extrapolation, predictions for the excitation energies of the five lowest excited states of the polyene radical cations are made for longer chain lengths.

  10. Radical surgery compared with intracavitary cesium followed by radical surgery in cervical carcinoma stage IB

    Energy Technology Data Exchange (ETDEWEB)

    Tinga, D.J.; Bouma, J.; Aalders, J.G. (Dept. of Obstetrics and Gynaecology, State Univ. Hospital, Groningen (Netherlands)); Hollema, H. (Dept. of Pathology, State Univ. Hospital, Groningen (Netherlands))

    1990-01-01

    Forty-nine patients aged {le} 45 years, with cervical carcinoma stage IB ({le} 3 cm) were treated with either primary radical surgery (n = 26), or intracavitary irradiation followed by radical surgery (n = 23). With primary surgery, ovarian function had been preserved in 15 of the 25 patients, who were alive and well. Seven of the primary surgery patients were irradiated postoperatively and 2 others with a central recurrence were cured by irradiation. One other patient, who was not irradiated postoperatively, had an intestinal metastasis and died of the disease. If any of the adverse prognostic factors (as reported in the literature) had been considered as an indication for postoperative irradiation, 17 patients instead of 7 would have been irradiated after primary radical surgery. In the comparable group of 23 patients treated by intracavitary irradiation and radical surgery (and in 4 cases postoperative irradiation as well) there was no recurrence. There was no significant statistical difference between the treatment results in the cesium + surgery group and those who underwent primary radical surgery. Young patients with early cervical carcinoma without prognostic indicators for postoperative irradiation can benefit from primary radical surgery, because their ovarian function can be preserved. (authors).

  11. Ovarian recurrence after radical trachelectomy for adenocarcinoma of the cervix.

    Science.gov (United States)

    Piketty, Mathilde; Barranger, Emmanuel; Najat, Mourra; François, Paye; Daraï, Emile

    2005-10-01

    Radical trachelectomy is an effective fertility-sparing treatment for women with early-stage cervical cancer. We describe the first reported ovarian recurrence after radical trachelectomy for stage IB1 adenocarcinoma cervical cancer.

  12. Bithiophene radical cation: Resonance Raman spectroscopy and molecular orbital calculations

    DEFF Research Database (Denmark)

    Grage, M.M.-L.; Keszthelyi, T.; Offersgaard, J.F.

    1998-01-01

    The resonance Raman spectrum of the photogenerated radical cation of bithiophene is reported. The bithiophene radical cation was produced via a photoinduced electron transfer reaction between excited bithiophene and the electron acceptor fumaronitrile in a room temperature acetonitrile solution a...

  13. Some Pluses and Minuses of Radical Constructivism in Mathematics Education.

    Science.gov (United States)

    Ellerton, Nerida; Clements, M. A.

    1992-01-01

    Reviews the radical constructivism movement in mathematics education. Benefits identified include learner ownership of mathematical learning; importance of social interaction; and identification of principles for improving mathematics teaching and learning. Weaknesses identified include overzealousness of some radical constructivists; downplaying…

  14. Pyrimidine nucleobase radical reactivity in DNA and RNA

    Science.gov (United States)

    Greenberg, Marc M.

    2016-11-01

    Nucleobase radicals are major products of the reactions between nucleic acids and hydroxyl radical, which is produced via the indirect effect of ionizing radiation. The nucleobase radicals also result from hydration of cation radicals that are produced via the direct effect of ionizing radiation. The role that nucleobase radicals play in strand scission has been investigated indirectly using ionizing radiation to generate them. More recently, the reactivity of nucleobase radicals resulting from formal hydrogen atom or hydroxyl radical addition to pyrimidines has been studied by independently generating the reactive intermediates via UV-photolysis of synthetic precursors. This approach has provided control over where the reactive intermediates are produced within biopolymers and facilitated studying their reactivity. The contributions to our understanding of pyrimidine nucleobase radical reactivity by this approach are summarized.

  15. Radical production from photosensitization of imidazoles

    Science.gov (United States)

    Corral Arroyo, P.; Gonzalez, L.; Steimer, S.; Aellig, R.; Volkamer, R. M.; George, C.; Bartels-Rausch, T.; Ammann, M.

    2015-12-01

    Reactions promoted by light are key in atmospheric chemistry. Some of them occur in the condensed phase of aerosols containing light absorbing organic compounds (George et al., 2015). This work explores the radical reactions initiated by near-UV light in mixtures of citric acid (CA) and imidazole-2-carboxaldehyde (IC) using NO as a probe molecule for HO2, by means of coated wall flow tube experiments. Citric acid may act as H atom or electron donor in condensed phase radical cycles. IC may act as a photosensitizer. The loss of NO was measured by a chemiluminescence detector. The dependence of the NO loss on the NO concentration, the IC/CA ratio in the film, relative humidity, light intensity, oxygen molar fraction were investigated as well as the HONO and NO2 yields. We also added halide salts to investigate the effect of a competing electron donor in the system and the output of halogens to the gas phase. We found a correlation between the loss of NO above the film and the molar ratio of IC/CA and the light intensity. The variation of the NO loss with oxygen corroborates a mechanism, in which the triplet excited state of IC is reduced by citric acid, to a reduced ketyl radical that transfers an electron to molecular oxygen, which in turn leads to production of HO2 radicals. Therefore, the NO loss in the gas phase is related to the production of HO2 radicals. Relative humidity had a strong impact on the HO2 output, which shows a maximum production rate at around 30%. The addition of halide ions (X- = Cl-, Br-, I-) increases the HO2 output at low concentration and decrease it at higher concentration when X2- radical ions likely scavenge HO2. We could preliminarily quantify for the first time the contribution of these processes to the oxidative capacity in the atmosphere and conclude that their role is significant for aerosol aging and potentially a significant source of halogen compounds to the gas phase.

  16. Demonstration of Improved Charge Transfer in Graphene/Au Nanorods Plasmonic Hybrids Stabilized by Benzyl Thiol Linkers

    Directory of Open Access Journals (Sweden)

    Giuseppe Valerio Bianco

    2016-01-01

    Full Text Available Hybrids based on graphene decorated with plasmonic gold (Au nanostructures are being investigated as possible materials combination to add to graphene functionalities of tunable plasmon resonance and enhanced absorption at selected wavelength in the visible-near-infrared region of the spectrum. Here, we report a solution drop-casting approach for fabricating stable hybrids based on chemical vapor deposition (CVD graphene and Au nanorods, which are able to activate effective charge transfer from graphene. We demonstrate that CVD graphene functionalization by benzyl thiol (BZT provides the linker to strong anchoring, via S-Au bonds, Au nanorods to graphene. Optical measurements by spectroscopic ellipsometry give evidence of the introduction of plasmon resonances at 1.85 and 2.25 eV in the Au nanorods/BZT/graphene hybrids, which enable surface enhanced Raman scattering (SERS detection. Furthermore, an effective electron transfer from graphene to Au nanorods, resulting in an enhancement of p-type doping of graphene with a consequent decrease of its sheet resistance, is probed by Raman spectroscopy and corroborated by electrical measurements.

  17. Substitution Effects and Linear Free Energy Relationships During Reduction of 4- Benzoyl-n-(4-substituted Benzyl)pyridinium Cations

    Science.gov (United States)

    Leventis, Nicholas; Zhang, Guo-Hui; Rawashdeh, Abdel-Monem M.; Sotiriou-Leventis, Chariklia; Gray, Hugh R. (Technical Monitor)

    2003-01-01

    In analogy to 4-(para-substituted benzoyl)-N-methylpyridinium cations (1-X's), the title species (2-X's, -X = -OCH3, -CH3, -H, -Br, -COCH3, -NO2) undergo two reversible, well-separated (E(sub 1/2) greater than or equal to 650 mV) one-electron reductions. The effect of substitution on the reduction potentials of 2-X's is much weaker than the effect of the same substituents on 1-X's: the Hammett rho-values are 0.80 and 0.93 for the 1st- and 2nd-e reduction of 2-X's vs. 2.3 and 3.3 for the same reductions of 1-X's, respectively. Importantly, the nitro group of 2-NO2 undergoes reduction before the 2nd-e reduction of the 4-benzoylpyridinium system. These results suggest that the redox potentials of the 4-benzoylpyridinium system can be course-tuned via p-benzoyl substitution and fine-tuned via para-benzyl substitution. Introducing the recently derived substituent constant of the -NO2(sup)- group (sigma para-NO2(sup)- = -0.97) yields an excellent correlation for the 3rd-e reduction of 2- NO2 (corresponding to the reduction of the carbonyl group) with the 2nd-e reduction of the other 2-X's, and confirms the electron donating properties of -NO2(sup)-.

  18. Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases

    Science.gov (United States)

    Min, Tongpil; Kasahara, Hiroyuki; Bedgar, Diana L.; Youn, Buhyun; Lawrence, Paulraj K.; Gang, David R.; Halls, Steven C.; Park, HaJeung; Hilsenbeck, Jacqueline L.; Davin, Laurence B.; Lewis, Norman G.; Kang, ChulHee

    2003-01-01

    Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

  19. Study on the Deactivation Kinetics of Pd(PPh3)2Cl2 in the Monocarbonylation of Benzyl Chloride

    Institute of Scientific and Technical Information of China (English)

    Zumin Qiu; Yunbing He; Huiping Xiao

    2004-01-01

    The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, and the concentration of Pd(PPh3)2Cl2 in the system is measured through absorptiometry.The result shows that the optimum condition of the chromogenic reaction between Pd2+ and PAN is:0.5 ml of 0.04% PAN added to 10 ml of Pd2+ solution (1.0×10-6-2.0×10-5 mol/L), and heated in a constant temperature water bath at 40 ℃ for about 30 min, with pH of the solution being about 3.0.The molar coefficient of absorption is 1.384×104 L/(mol.cm); the orders of the hydrolytic reaction to the concentration of Pd(PPh3)2Cl2, PPh3, phenylacetic acid and NaOH are 0.5, minus 0.8, 2 and 1.2,respectively. The activation energy (E) of the hydrolytic reaction is 75.59 k J/mol, and the pre-exponential factor is 1.68×1012.

  20. A polytetrafluoroethylene porous membrane and dimethylhexadecylamine quaternized poly (vinyl benzyl chloride) composite membrane for intermediate temperature fuel cells

    Science.gov (United States)

    Cao, Yuan-Cheng; Xu, Chenxi; Zou, Linling; Scott, Keith; Liu, Jiyan

    2015-10-01

    A composite material for phosphoric acid (PA) loaded membrane was prepared using a porous polytetrafluoroethylene (PTFE) thin film. N, N-Dimethylhexadecylamine partially quaternized poly (vinyl benzyl chloride) (qPVBzCl-) was synthesized as the substrate for the phosphoric acid loaded polymer membrane. SEM observation indicated that the pores were filled with the qPVBzCl-. The maximum PA loading level was calculated to be 4.67-5.12 per repeat unit on average. TGA results showed that resultant composite membrane was stable in the intermediate temperature from 100 °C to 200 °C. The composite membrane tensile stress was 56.23 MPa, and the Young's Modulus was 0.25 GPa, and the fractured elongation was 23%. The conductivity of the composite membrane after the PA addition (H3PO4@PTFE/qPVBzCl-) increased from 0.085 S cm-1 to 0.11 S cm-1 from 105 °C to 180 °C. The peak power density of the H2/O2 at 175 °C under low humidity condition (<1%) for H3PO4@PTFE/qPVBzCl- membranes was 360 mW cm-2.

  1. Benzyl 2-β-Glucopyranosyloxybenzoate, a New Phenolic Acid Glycoside from Sarcandra glabra

    Directory of Open Access Journals (Sweden)

    Xudong Xu

    2012-05-01

    Full Text Available From the whole plant of Sarcandra glabra, a new phenolic acid glycoside, benzyl 2-β-glucopyranosyloxybenzoate (1, together with seven known compounds including eleutheroside B1 (2, 5-O-caffeoylshikimic acid (3, (–-(7S, 8R-dihydrodehydro-diconiferyl alcohol (4, (–-(7S, 8R-dihydrodehydrodiconiferyl alcohol 9-, 9′- and 4-O-â-D-glucopyranoside (57, and (–-(7S, 8R-5-methoxydihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (8 was isolated. Their structures were elucidated by spectral analysis including 1D-, 2D-NMR and HR-ESI-MS. Compound 2 was found to exhibit potent cytotoxic activity against BGC-823 and A2780 cancer cell lines using MTT method with IC50 value of 2.53 and 1.85 µM, respectively.

  2. Suppression of FOXQ1 in benzyl isothiocyanate-mediated inhibition of epithelial-mesenchymal transition in human breast cancer cells.

    Science.gov (United States)

    Sehrawat, Anuradha; Kim, Su-Hyeong; Vogt, Andreas; Singh, Shivendra V

    2013-04-01

    We showed previously that breast cancer chemoprevention with benzyl isothiocyanate (BITC) in MMTV-neu mice was associated with induction of E-cadherin protein in vivo. Loss of E-cadherin expression and induction of mesenchymal markers (e.g. vimentin) are biochemical hallmarks of epithelial-mesenchymal transition (EMT), a developmental process implicated in progression of cancer to aggressive state. This study offers novel insights into the mechanism by which BITC inhibits EMT. Exposure of MDA-MB-231, SUM159 and MDA-MB-468 human breast cancer cells to BITC (2.5 and 5 µM) resulted in transcriptional repression of urokinase-type plasminogen activator (uPA) as well as its receptor (uPAR). However, ectopic expression of uPAR in MDA-MB-468 cells failed to confer protection against induction of E-cadherin and inhibition of cell invasion/migration resulting from BITC treatment. The BITC-mediated induction of E-cadherin and inhibition of cell migration was sustained in MDA-MB-231 and SUM159 cells transiently transfected with an uPAR-targeted small interfering RNA. Overexpression of Forkhead Box Q1 (FOXQ1), whose protein and messenger RNA levels were decreased by BITC treatment in cells and MDA-MB-231 xenografts, conferred marked protection against BITC-mediated inhibition of EMT and cell migration. In conclusion, this study implicates FOXQ1 suppression in BITC-mediated inhibition of EMT in human breast cancer cells.

  3. n-Butyl benzyl phthalate promotes breast cancer progression by inducing expression of lymphoid enhancer factor 1.

    Directory of Open Access Journals (Sweden)

    Tsung-Hua Hsieh

    Full Text Available Environmental hormones play important roles in regulating the expression of genes involved in cell proliferation, drug resistance, and breast cancer risk; however, their precise role in human breast cancer cells during cancer progression remains unclear. To elucidate the effect of the most widely used industrial phthalate, n-butyl benzyl phthalate (BBP, on cancer progression, we evaluated the results of BBP treatment using a whole human genome cDNA microarray and MetaCore software and selected candidate genes whose expression was changed by more than ten-fold by BBP compared with controls to analyze the signaling pathways in human breast cancer initiating cells (R2d. A total of 473 genes were upregulated, and 468 were downregulated. Most of these genes are involved in proliferation, epithelial-mesenchymal transition, and angiogenesis signaling. BBP induced the viability, invasion and migration, and tube formation in vitro, and Matrigel plug angiogenesis in vivo of R2d and MCF-7. Furthermore, the viability and invasion and migration of these cell lines following BBP treatment was reduced by transfection with a small interfering RNA targeting the mRNA for lymphoid enhancer-binding factor 1; notably, the altered expression of this gene consistently differentiated tumors expressing genes involved in proliferation, epithelial-mesenchymal transition, and angiogenesis. These findings contribute to our understanding of the molecular impact of the environmental hormone BBP and suggest possible strategies for preventing and treating human breast cancer.

  4. A new validated method for the simultaneous determination of benzocaine, propylparaben and benzyl alcohol in a bioadhesive gel by HPLC.

    Science.gov (United States)

    Pérez-Lozano, P; García-Montoya, E; Orriols, A; Miñarro, M; Ticó, J R; Suñé-Negre, J M

    2005-10-04

    A new HPLC-RP method has been developed and validated for the simultaneous determination of benzocaine, two preservatives (propylparaben (nipasol) and benzyl alcohol) and degradation products of benzocaine in a semisolid pharmaceutical dosage form (benzocaine gel). The method uses a Nucleosil 120 C18 column and gradient elution. The mobile phase consisted of a mixture of methanol and glacial acetic acid (10%, v/v) at different proportion according to a time-schedule programme, pumped at a flow rate of 2.0 ml min(-1). The DAD detector was set at 258 nm. The validation study was carried out fulfilling the ICH guidelines in order to prove that the new analytical method, meets the reliability characteristics, and these characteristics showed the capacity of analytical method to keep, throughout the time, the fundamental criteria for validation: selectivity, linearity, precision, accuracy and sensitivity. The method was applied during the quality control of benzocaine gel in order to quantify the drug (benzocaine), preservatives and degraded products and proved to be suitable for rapid and reliable quality control method.

  5. Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases.

    Science.gov (United States)

    Min, Tongpil; Kasahara, Hiroyuki; Bedgar, Diana L; Youn, Buhyun; Lawrence, Paulraj K; Gang, David R; Halls, Steven C; Park, HaJeung; Hilsenbeck, Jacqueline L; Davin, Laurence B; Lewis, Norman G; Kang, ChulHee

    2003-12-12

    Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

  6. Benzyl butyl phthalate promotes adipogenesis in 3T3-L1 preadipocytes: A High Content Cellomics and metabolomic analysis.

    Science.gov (United States)

    Yin, Lei; Yu, Kevin Shengyang; Lu, Kun; Yu, Xiaozhong

    2016-04-01

    Benzyl butyl phthalate (BBP) has been known to induce developmental and reproductive toxicity. However, its association with dysregulation of adipogenesis has been poorly investigated. The present study aimed to examine the effect of BBP on the adipogenesis, and to elucidate the underlying mechanisms using the 3T3-L1 cells. The capacity of BBP to promote adipogenesis was evaluated by multiple staining approaches combined with a High Content Cellomics analysis. The dynamic changes of adipogenic regulatory genes and proteins were examined, and the metabolite profile was identified using GC/MC based metabolomic analysis. The High Content analysis showed BBP in contrast with Bisphenol A (BPA), a known environmental obesogen, increased lipid droplet accumulation in a similar dose-dependent manner. However, the size of the lipid droplets in BBP-treated cells was significantly larger than those in cells treated with BPA. BBP significantly induced mRNA expression of transcriptional factors C/EBPα and PPARγ, their downstream genes, and numerous adipogenic proteins in a dose and time-dependent manner. Furthermore, GC/MC metabolomic analysis revealed that BBP exposure perturbed the metabolic profiles that are associated with glyceroneogenesis and fatty acid synthesis. Altogether, our current study clearly demonstrates that BBP promoted the differentiation of 3T3-L1 through the activation of the adipogenic pathway and metabolic disturbance.

  7. Antimicrobial filtration with electrospun poly(vinyl alcohol) nanofibers containing benzyl triethylammonium chloride: Immersion, leaching, toxicity, and filtration tests.

    Science.gov (United States)

    Park, Jeong-Ann; Kim, Song-Bae

    2017-01-01

    Antimicrobial electrospun poly(vinyl alcohol) (PVA) nanofibers were synthesized by impregnating benzyl triethylammonium chloride (BTEAC) as an antimicrobial agent into PVA nanofibers. The BTEAC-PVA nanofibers were heat-methanol treated during the preparation for various tests. The BTEAC-PVA nanofibers became more hydrophilic than the PVA nanofibers due to incorporation of BTEAC. Through heat-methanol treatment, thermal property, crystallinity, and water stability of BTEAC-PVA nanofibers were improved considerably. The immersion test shows that heat-methanol treatment has an advantage over heat treatment to maintain BTEAC content in BTEAC-PVA nanofibers. The acute toxicity test demonstrates that the 24-h EC50 and 48-h EC50 values (EC50 = median effective concentration) of BTEAC to Daphnia magna were 113 and 90 mg/L, respectively. The leaching test indicates that the BTEAC concentration leached from BTEAC-PVA nanofibers was far below the concentration affecting the immobilization of D. magna. For antimicrobial filtration tests, the BTEAC-PVA nanofibers were deposited onto glass fiber filter. The antimicrobial filtration test was conducted against bacteria (Escherichia coli, Staphylococcus aureus) and bacteriophages (MS2, PhiX174), demonstrating that the BTEAC-PVA nanofibers could enhance the removal of E. coli and S. aureus considerably but not the removal of MS2 and PhiX174 under dynamic flow conditions.

  8. Vibrational spectroscopy, intramolecular CH⋯O interaction and conformational analysis of 2,5-dimethyl-benzyl benzoate

    Science.gov (United States)

    Viana, Rommel B.; Ribeiro, Gabriela L. O.; Valencia, Leidy J.; Varela, Jaldyr J. G.; Viana, Anderson B.; da Silva, Albérico B. F.; Moreno-Fuquen, Rodolfo

    2016-12-01

    The aim of this study was to report the spectroscopic and electronic properties of 2,5-dimethyl-benzyl benzoate. FT-IR and Raman vibrational spectral analyses were performed, while a computational approach was used to elucidate the vibrational frequency couplings. The electronic properties were predicted using the Density Functional Theory, while the G3MP2 method was employed in the thermochemical calculation. A conformational analysis, frontier orbitals, partial atomic charge distribution and the molecular electrostatic potential were also estimated. Concerning to the dihedral angles in the ester group, a conformational analysis showed a barrier energy of 10 kcal mol-1, while other small barriers (below 0.6 kcal mol-1) were predicted within the potential surface energy investigation. Insights into the relative stability among the different positions of methyl groups in the phenyl ring demonstrated that the energy gaps were lower than 1 kcal mol-1 among the regioisomers. In addition, the Quantum Theory of Atoms in Molecules (QTAIM) was used to understand the intramolecular CH⋯O interaction in the title compound, while various methodologies were applied in the atomic charge distribution to evaluate the susceptibility to the population method.

  9. The plasticizer butyl benzyl phthalate induces genomic changes in rat mammary gland after neonatal/prepubertal exposure

    Directory of Open Access Journals (Sweden)

    Lamartiniere Coral A

    2007-12-01

    Full Text Available Abstract Background Phthalate esters like n-butyl benzyl phthalate (BBP are widely used plasticizers. BBP has shown endocrine-disrupting properties, thus having a potential effect on hormone-sensitive tissues. The aim of this study is to determine the effect of neonatal/prepubertal exposure (post-natal days 2–20 to BBP on maturation parameters and on the morphology, proliferative index and genomic signature of the rat mammary gland at different ages of development (21, 35, 50 and 100 days. Results Here we show that exposure to BBP increased the uterine weight/body weight ratio at 21 days and decreased the body weight at time of vaginal opening. BBP did not induce significant changes on the morphology of the mammary gland, but increased proliferative index in terminal end buds at 35 days and in lobules 1 at several ages. Moreover, BBP had an effect on the genomic profile of the mammary gland mainly at the end of the exposure (21 days, becoming less prominent thereafter. By this age a significant number of genes related to proliferation and differentiation, communication and signal transduction were up-regulated in the glands of the exposed animals. Conclusion These results suggest that BBP has an effect in the gene expression profile of the mammary gland.

  10. Photosensized Controlling Benzyl Methacrylate-Based Matrix Enhanced Eu3+ Narrow-Band Emission for Fluorescence Applications

    Directory of Open Access Journals (Sweden)

    Mei-Hsiang Lin

    2012-03-01

    Full Text Available This study synthesized a europium (Eu3+ complex Eu(DBM3Cl-MIP (DBM = dibenzoyl methane; Cl-MIP = 2-(2-chlorophenyl-1-methyl-1H-imidazo[4,5-f][1,10]phenanthroline dispersed in a benzyl methacrylate (BMA monomer and treated with ultraviolet (UV light for polymerization. Spectral results showed that the europium complex containing an antenna, Cl-MIP, which had higher triplet energy into the Eu3+ energy level, was an energetically enhanced europium emission. Typical stacking behaviors of π–π interactions between the ligands and the Eu3+-ion were analyzed using single crystal X-ray diffraction. Regarding the luminescence performance of this europium composite, the ligand/defect emission was suppressed by dispersion in a poly-BMA (PBMA matrix. The underlying mechanism of the effective enhancement of the pure Eu3+ emission was attributed to the combined effects of structural modifications, defect emissions, and carrier charge transfer. Fluorescence spectra were compared to the composite of optimized Eu3+ emission where they were subsequently chelated to four metal ions via carboxylate groups on the BMA unit. The optical enhanced europium composite clearly demonstrated highly efficient optical responses and is, therefore a promising application as an optical detection material.

  11. Preparation of manganese oxide immobilized on SBA-15 by atomic layer deposition as an efficient and reusable catalyst for selective oxidation of benzyl alcohol in the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Mahdavi, Vahid, E-mail: v-mahdavi@araku.ac.ir; Mardani, Mahdieh

    2015-04-01

    Manganese oxide supported on mesoporous silica SBA-15 catalyst (Mn-SBA-15) was tested with Mn contents in the range of 0.8–23 wt%. Samples were prepared by the controlled grafting process of atomic layer deposition (ALD). Other sample was prepared for comparisons by the wet impregnation method. These samples were characterized by the techniques of ICP, XRD, SEM, Raman, FT-IR spectroscopy, diffuse reflectance UV–Vis, TGA-DSC, and N{sub 2} absorption–desorption surface area measurement. Results indicated that anchored manganese oxide particles have been successfully synthesized over the surface of SBA-15. These samples contained Red-Ox ion pairs of Mn{sup 2+} and Mn{sup 3+} highly dispersed on the mesoporous silica surface. The impregnated sample exhibited lower surface area and contained Red-Ox ion pairs of Mn{sup 3+} and Mn{sup 4+} more aggregated particles on the SBA-15 surface. Results determined Mn-SBA-15 as an efficient and selective catalyst for oxidation of benzyl alcohol with tert-butylhydroperoxide in liquid phase. In accordance with expectations, there was a negligible amount of leaching of immobilized manganese oxide from the support during the reaction, because of strong surface interaction between manganese oxide and hydroxyls groups. The influences of reaction temperature, reaction time, solvent, TBHP/benzyl alcohol molar ratio, amount of catalyst and reusability were investigated. Under optimized conditions (0.2 g catalyst, TBHP/benzyl alcohol molar ratio 1, solvent acetonitrile; T = 90 °C; reaction time 8 h), results achieved 70% conversion of benzyl alcohol and 100% selectivity to benzaldehyde. - Highlights: • Manganese oxide immobilized on SBA-15 were prepared by atomic layer deposition (ALD). • Oxidation of benzyl alcohol to benzaldehyde over this catalyst were investigated. • Effects of loading of manganese oxide, T, oxidant/alcohol ratio were investigated. • The leaching of manganese oxide from support during the reaction was

  12. Biochemistry and pathology of radical-mediated protein oxidation

    DEFF Research Database (Denmark)

    Dean, R T; Fu, S; Stocker, R

    1997-01-01

    Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several catego...

  13. α-Carbonyl Radical Cyclizatio n in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    SHA Chin-Kang; CHIU Rei-Torng; LIH Shinn-Horng; SANTHOSH K. C.; CHANG Ching-Jung; TSENG Wei-Hong; HO Wen-Yueh

    2001-01-01

    @@ Intramolecular radical cyclization reactions are now used routinely to synthesize carbocyclic and heterocyclic structures. We have reported that α-carbonyl radicals 1, generated from the corresponding iodo ketones or enones, underwent intramolecular radical cyclization smoothly to afford products 2.1, 2,3

  14. Responsibility for radical change in addressing climate change

    NARCIS (Netherlands)

    Bouvrie, des N.; Karlsson-Vinkhuyzen, S.I.S.E.; Jollands, N.

    2014-01-01

    To radically address the problem of climate change, it is not enough to modify specific attitudes and behaviors while upholding the present paradigms. This article aims to show why modifications will never bring about radical carbon emission reductions. We discuss what it implies to desire radical c

  15. Regularities and Radicals in Near-rings

    Institute of Scientific and Technical Information of China (English)

    N.J. Groenewald

    2002-01-01

    Let F be a regularity for near-rings and F(R) the largest FR-regular ideal in R. In the first part of this paper, we introduce the concepts of maximal Fmodular ideals and F-primitive near-rings to characterize F(R) for any near-ring regularity F. Under certain conditions, F(R) is equal to the intersection of all the maximal F-modular ideals of R. As examples, we apply this to the different analogs of the Brown-McCoy radicals and also the Behrens radicals. In the last part of this paper, we show that for certain regularities, the class of F-primitive near-rings forms a special class.

  16. Enacting a social ecology: radically embodied intersubjectivity.

    Science.gov (United States)

    McGann, Marek

    2014-01-01

    Embodied approaches to cognitive science frequently describe the mind as "world-involving," indicating complementary and interdependent relationships between an agent and its environment. The precise nature of the environment is frequently left ill-described, however, and provides a challenge for such approaches, particularly, it is noted here, for the enactive approach which emphasizes this complementarity in quite radical terms. This paper argues that enactivists should work to find common cause with a dynamic form of ecological psychology, a theoretical perspective that provides the most explicit theory of the psychological environment currently extant. In doing so, the intersubjective, cultural nature of the ecology of human psychology is explored, with the challenges this poses for both enactivist and ecological approaches outlined. The theory of behavior settings (Barker, 1968; Schoggen, 1989) is used to present a framework for resolving some of these challenges. Drawing these various strands together an outline of a radical embodied account of intersubjectivity and social activity is presented.

  17. Freedom Now! Radical Jazz and Social Movements

    Directory of Open Access Journals (Sweden)

    Przemysław Pluciński

    2014-01-01

    Full Text Available Music is obviously not only an aesthetic phenomenon. It is embeddedin a dense network of social relations. However, its social involvementis rather ambiguous, particularly since the second half of the twentiethcentury. On the one hand, music is one of the main elements of culturalcapitalism and a part of the system of domination. On the other hand,music provokes, (coproduces or possibly strengthens and coexists witha number of counterdiscourses and social projects of counterhegemoniccharacter.The main objective of the paper is to examine relationships between both, revolutionary jazz and revolutionary social movements, namely the civil rights movement, but above all radical movements, especially black power movement. The crucial questions I am interested in are problems of selforganization, performative social practices, as well as alternatives elaborated by radical-oriented jazz circles in various social dimensions, for instance economic or symbolic.

  18. International Radical Cystectomy Consortium: A way forward

    Directory of Open Access Journals (Sweden)

    Syed Johar Raza

    2014-01-01

    Full Text Available Robot-assisted radical cystectomy (RARC is an emerging operative alternative to open surgery for the management of invasive bladder cancer. Studies from single institutions provide limited data due to the small number of patients. In order to better understand the related outcomes, a world-wide consortium was established in 2006 of patients undergoing RARC, called the International Robotic Cystectomy Consortium (IRCC. Thus far, the IRCC has reported its findings on various areas of operative interest and continues to expand its capacity to include other operative modalities and transform it into the International Radical Cystectomy Consortium. This article summarizes the findings of the IRCC and highlights the future direction of the consortium.

  19. Editorial: RADICALISM AND POLITICS OF RELIGION

    Directory of Open Access Journals (Sweden)

    Editorial Al-Jami'ah: Journal of Islamic Studies

    2008-02-01

    Full Text Available Radical Islamism has become the “sexiest” issue in the international scholarship of religion since the September 11 tragedy in 2001. It has been associated with a number of terrorist attacks not only in the West but also in Muslim countries. Every single of radical Islamism has caught the interest of not only scholars and policy makers but also general public. Interestingly, the general assumption that religion is the source of peace has been seriously challenged, not by non-religious communities, but by the violent practices of particular religious groups, however small they are. Indeed, there are certain groups striving for Islam but by using acts which could give awful image on Islam itself and against humanity.

  20. Mechanisms of radical removal by SO2

    DEFF Research Database (Denmark)

    Rasmussen, Christian Lund; Glarborg, Peter; Marshall, Paul

    2007-01-01

    It is well established from experiments in premixed, laminar flames, jet-stirred reactors, flow reactors, and batch reactors that SO2 acts to catalyze hydrogen atom removal at stoichiometric and reducing conditions. However, the commonly accepted mechanism for radical removal, SO2 + H...... that the interaction of SO, with the radical pool is more complex than previously assumed, involving HOSO and SO, as well as, at high temperatures also HSO, SH, and S. The revised mechanism with a high rate constant for H + SO2 recombination and with SO + H2O, rather than SO2 + H-2, as major products of the HOSO + H...... reaction is in agreement with a range of experimental results from batch and flow reactors, as well as laminar flames....

  1. How Hume's Philosophy Informed Radical Behaviorism.

    Science.gov (United States)

    Nuzzolilli, Andrew E; Diller, James W

    2015-05-01

    The present paper analyzes consistencies between the philosophical systems of David Hume and B. F. Skinner, focusing on their conceptualization of causality and attitudes about scientific behavior. The ideas that Hume initially advanced were further developed in Skinner's writings and shaped the behavior-analytic approach to scientific behavior. Tracing Skinner's logical antecedents allows for additional historical and philosophical clarity when examining the development of radical behaviorism.

  2. Can the United States Defeat Radical Islam

    Science.gov (United States)

    2008-05-22

    or expatriate communities, identify with Al Qaeda’s radical message and find a new source of spiritual commitment in it. Albert Bandura in his...first Century. New York: Berkley Books, 2004. Bandura , Albert . “Mechanisms of moral disengagement.” Origins of Terrorism: Psychologies, Ideologies...standards that their families, their religious leaders, and their government seek to instill. This disengagement is activated, according to Bandura

  3. A Radical New Mach 7 Engine

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Most engines compress air, add fuel and burn it, and then allow theheated gas to expand, creating power or thrust. A radical aircraft enginedevised by ONERA, France’s equivalent of NASA, does the opposite.The Priam inverse-cycle" engine is designed for hypersonic speedsabove Mach 4 (2, 650 mph). Conventional jets do not work at suchspeeds, because the air becomes so hot when it is rammed into the

  4. Oxygen radical functionalization of boron nitride nanosheets

    OpenAIRE

    MAY, PETER; Coleman, Jonathan; MCGOVERN, IGNATIUS; GOUNKO, IOURI; Satti, Amro

    2012-01-01

    PUBLISHED The covalent chemical functionalization of exfoliated hexagonal boron-nitride nanosheets (BNNSs) is achieved by the solution phase oxygen radical functionalization of boron atoms in the h-BN lattice. This involves a two-step procedure to initially covalently graft alkoxy groups to boron atoms and the subsequent hydrolytic defunctionalisation of the groups to yield hydroxyl-functionalized BNNSs (OH-BNNSs). Characterization of the functionalized-BNNSs using HR-TEM, Raman, UV-Vis, F...

  5. Internet Radicalization: Actual Threat or Phantom Menace?

    Science.gov (United States)

    2012-09-01

    morphine of ideas—self-induced at initiation, but involuntary once hooked. In correlation with this picture, juveniles have been identified at risk...network that she ultimately sought to assist. 5. Mohammed Hassan Khalid: Mohammed Hassan Khalid was radicalized as a juvenile and is believed to be...Sulejah Hadzovic Betim Kaziu and Sulejah Hadzovic came from Muslim families and grew up in Brooklyn, New York. Kaziu was convicted and sentenced to

  6. AQUEOUS STABLE FREE RADICAL POLYMERIZATION PROCESSES

    Institute of Scientific and Technical Information of China (English)

    Andrea R. Szkurhan; Michael K. Georges

    2004-01-01

    An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations,under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.

  7. Radical induction theory of ulcerative colitis

    Institute of Scientific and Technical Information of China (English)

    Jay Pravda

    2005-01-01

    To propose a new pathogenesis called Radical Induction to explain the genesis and progression of ulcerative colitis (UC). UC is an inflammatory bowel disease. Colonic inflammation in UC is mediated by a buildup of white blood cells (WBCs) within the colonic mucosal lining; however,to date there is no answer for why WBCs initially enter the colonic mucosa to begin with. A new pathogenesis termed "Radical Induction Theory" is proposed to explain this and states that excess un-neutralized hydrogen peroxide, produced within colonic epithelial cells as a result of aberrant cellular metabolism, diffuses through cell membranes to the extracellular space where it is converted to the highly damaging hydroxyl radical resulting in oxidative damage to structures comprising the colonic epithelial barrier. Once damaged, the barrier is unable to exclude highly immunogenic fecal bacterial antigens from invading the normally sterile submucosa. This antigenic exposure provokes an initial immune response of WBC infiltration into the colonic mucosa. Once present in the mucosa,WBCs are stimulated to secrete toxins by direct exposure to fecal bacteria leading to mucosal ulceration and bloody diarrhea characteristic of this disease.

  8. Radical correction of Budd-Chiari syndrome

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-qiang; WANG Zhong-gao; MENG Qing-you; SANG Hong-fei; QIAN Ai-min; DUAN Peng-fei; RONG Jian-jie

    2007-01-01

    Background Interventional therapy is widely accepted as the first choice for the treatment of the Budd-Chiari syndrome,but the use of radical correctional therapy should not be discarded. This study describes radical correction by controlling bleeding from distal end of pathological segment of the inferior vena cava (IVC) and discusses potential surgical errors and postoperative complications.Methods Of the 216 patients in the study, 78 were treated with simple membranectomy, 64 with dissection of the pathological segment of the IVC and vascular prosthesis or pericardial patch plasty, 60 with resection of the pathological segment of the IVC and orthotopic graft transplantation with vascular prosthesis, and 14 with resection of the occlusive main hepatic vein and its upper IVC, hepatic venous outflow plasty and vascular prosthesis orthotopic graft transplantation from the hepatic venous entrance to the IVC of right atrial ostium.Results Except 14 cases who were discharged after hepatic vein outflow plasty, four cases died postoperatively, and 198 patients were discharged without complications. The symptoms of 15 patients were relieved partially and 2 without any change. There were no deaths intraoperatively. Of the 112 cases who were followed up for 72 months, 13 suffered from a relapse.Conclusions Radical correction is a beneficial therapy in the treatment of Budd-Chiari syndrome.

  9. Removal of NOx by radical injection

    Institute of Scientific and Technical Information of China (English)

    LIN He; GAO Xiang; LUO Zhongyang; CEN Kefa; PEI Meixiang; HUANG Zhen

    2004-01-01

    Removal of NOx ( DeNOx, NOx is the total of NO and NO2) from flue gas by radical injection has been investigated . The discharge characteristics were examined and the steady streamer corona was acquired by adjusting the nozzle gases properly. It was found that an increase in the voltage resulted in a decrease in the NO concentration and the concentration of the NO2 increased at low voltages but decreased as the voltage rose to a certain level. The DeNOx efficiency increased as the applied voltage rose and reached a maximum of 70% when the voltage approached the breakdown voltage. The hypothetical mechanism of NOx removal suggested that the radicals formed in the discharge process converted the NO and NO2 into acidic species. The Monte Carlo method was used to calculate the rate coefficients and the productivity of the radicals, and then the concentrations of both NO and NO2 and the DeNOx efficiencies were calculated with chemical kinetics. The calculated DeNOx efficiencies were comparable with the experimental DeNOx efficiencies at low voltages, but were lower at high voltages.

  10. Chemical Nonlinearities and Radical Pair Lifetime Estimation

    Science.gov (United States)

    Robinson, Gregory

    2013-03-01

    Much attention has recently developed around chemical reactions that depend on applied static magnetic fields as weak as earth's. This interest is largely motivated by experiments that implicate the role of spin-selective radical pair recombination in biological magnetic sensing. Existing literature uses a straightforward calculation to approximate the expected lifetime of coherent radical pairs as a function of the minimum RF amplitude that is observed to disrupt magnetic navigation, apparently by decohering the radical pair via electronic Zeeman excitations. But we show that chemical nonlinearities can preclude direct computation of coherent pair lifetime without considering the cellular signalling mechanisms involved, and discuss whether it can explain the surprising fragility of some animals' compass sense. In particular, we demonstrate that an autocatalytic cycle can introduce threshold effects on the disruption sensitivity to applied oscillatory magnetic fields. We will show examples in the mean-field limit and consider the consequences of noise and fluctuations in the Freidlin-Wentzell picture of perturbed dynamical systems.

  11. Complications of Radical Cystectomy and Orthotopic Reconstruction

    Directory of Open Access Journals (Sweden)

    Wei Shen Tan

    2015-01-01

    Full Text Available Radical cystectomy and orthotopic reconstruction significant morbidity and mortality despite advances in minimal invasive and robotic technology. In this review, we will discuss early and late complications, as well as describe efforts to minimize morbidity and mortality, with a focus on ileal orthotopic bladder substitute (OBS. We summarise efforts to minimize morbidity and mortality including enhanced recovery as well as early and late complications seen after radical cystectomy and OBS. Centralisation of complex cancer services in the UK has led to a fall in mortality and high volume institutions have a significantly lower rate of 30-day mortality compared to low volume institutions. Enhanced recovery pathways have resulted in shorter length of hospital stay and potentially a reduction in morbidity. Early complications of radical cystectomy occur as a direct result of the surgery itself while late complications, which can occur even after 10 years after surgery, are due to urinary diversion. OBS represents the ideal urinary diversion for patients without contraindications. However, all patients with OBS should have regular long term follow-up for oncological surveillance and to identify complications should they arise.

  12. [Free radicals and hepatic ischemia-reperfusion].

    Science.gov (United States)

    Szijártó, Attila

    2015-11-22

    The critical importance of the ischemic-reperfusive injury is well documented with regards to numerous organs and clinical conditions. Oxygen free radicals play a central role in the mediation of the injury, which dominantly influences the prevalence of postoperative complications, (long term) organ damage, and the potential manifestation of systemic reactions. The both anatomically and pathophysiologically unique ischemic-reperfusive injury of the liver, which is expressively vulnerable to free radicals, is of utmost importance in liver surgery. Several techniques (adaptive maneuvers, chemical agents) are known to ameliorate the reperfusive injury. Based on the prior research of the workgroup of the author, the aim of the current article is to overview the set of measures capable of attenuating ischemic-reperfusive injury (ischemic preconditioning, -perconditioning, administration of adenosine, -inosine, -levosimendan, and -poly-ADP-ribose-polymerase inhibitor), with special attention to the ischemic-reperfusive injury of the liver, as well as the special pathophysiological role of free radicals in mediating hepatic damage.

  13. Radicals contributing to preirradiation graft polymerization onto porous polyethylene

    Science.gov (United States)

    Uezu, Kazuya; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Ishigaki, Isao

    Porous polyethylene hollow fiber was irradiated by an electron beam at 160 kGy and 8 kGy/min. The concentrations of the radicals such as alkyl, allyl and peroxy were determined by analyzing an integral form of ESR spectra. The comparison of the decay of the radicals with and without contact with air demonstrated that the key radical contributing to the preirradiation graft polymerization is the alkyl radical. The decay of the alkyl radical was simulated by the diffusion-controlled model in the spherical crystallites of polyethylene.

  14. Generation and propagation of radical reactions on proteins

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    2001-01-01

    The oxidation of proteins by free radicals is thought to play a major role in many oxidative processes within cells and is implicated in a number of human diseases as well as ageing. This review summarises information on the formation of radicals on peptides and proteins and how radical damage may...... be propagated and transferred within protein structures. The emphasis of this article is primarily on the deleterious actions of radicals generated on proteins, and their mechanisms of action, rather than on enzymatic systems where radicals are deliberately formed as transient intermediates. The final section...

  15. What is Radical Behaviorism? A Review of Jay Moore's Conceptual Foundations of Radical Behaviorism

    Science.gov (United States)

    Baum, William M

    2011-01-01

    B. F. Skinner founded both radical behaviorism and behavior analysis. His founding innovations included: a versatile preparation for studying behavior; explicating the generic nature of stimulus and response; a pragmatic criterion for defining behavioral units; response rate as a datum; the concept of stimulus control; the concept of verbal behavior; and explicating the explanatory power of contingencies. Besides these achievements, however, Skinner also made some mistakes. Subsequent developments in radical behaviorist thought have attempted to remedy these mistakes. Moore's book presents a “party line” version of radical behaviorism. It focuses narrowly on a few of Skinner's concepts (mostly mentalism and verbal behavior) and contains no criticism of his mistakes. In fact, Moore adds a few mistakes of his own manufacture; for example, he insists that the mental realm does not exist—an unprovable and distracting assertion. The book's portrayal of behavior analysis would have been current around 1960; it mentions almost none of the developments since then. It also includes almost no developments in radical behaviorism since Skinner. Moore's book would give an unwary reader a highly distorted picture of contemporary behavior analysis and radical behaviorism.

  16. Peroxy radical chemistry and OH radical production during the NO3-initiated oxidation of isoprene

    Directory of Open Access Journals (Sweden)

    P. O. Wennberg

    2012-01-01

    Full Text Available Peroxy radical reactions (RO2 + RO2 from the NO3-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (>~80%, consistent with other studies. We further see evidence of significant hydroxyl radical (OH formation in this system, which we propose comes from RO2 + HO2 reactions with a yield of ~42–62%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ~35%. The branching ratio of the radical propagating, carbonyl- and alcohol-forming, and dimer-forming channels of the RO2 + RO2 reaction are found to be ~18–38%, ~59–77%, and ~3–4%, respectively. HO2 formation in this system is lower than has been previously assumed. Addition of RO2 to isoprene is suggested as a possible route to the formation of several isoprene dimer compounds (ROOR. The nitrooxy, allylic, and C5 peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date.

  17. Peroxy radical chemistry and OH radical production during the NO3-initiated oxidation of isoprene

    Directory of Open Access Journals (Sweden)

    J. H. Seinfeld

    2012-08-01

    Full Text Available Peroxy radical reactions (RO2 + RO2 from the NO3-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (~ 80%, consistent with other studies. We further see evidence of significant hydroxyl radical (OH formation in this system, which we propose comes from RO2 + HO2 reactions with a yield of ~38–58%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ~35%. The branching ratio of the radical propagating, carbonyl- and alcohol-forming, and organic peroxide-forming channels of the RO2 + RO2 reaction are found to be ~18–38%, ~59–77%, and ~3–4%, respectively. HO2 formation in this system is lower than has been previously assumed. Addition of RO2 to isoprene is suggested as a possible route to the formation of several isoprene C10-organic peroxide compounds (ROOR. The nitrooxy, allylic, and C5 peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date.

  18. Covalently Bound Nitroxyl Radicals in an Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Barbara K.; Braunecker, Wade A.; Bobela, David C.; Nanayakkara, Sanjini U.; Reid, Obadiah G.; Johnson, Justin C.

    2016-09-15

    A series of covalent organic framework (COF) structures is synthesized that possesses a tunable density of covalently bound nitroxyl radicals within the COF pores. The highest density of organic radicals produces an electron paramagnetic resonance (EPR) signal that suggests the majority of radicals strongly interact with other radicals, whereas for smaller loadings the EPR signals indicate the radicals are primarily isolated but with restricted motion. The dielectric loss as determined from microwave absorption of the framework structures compared with an amorphous control suggests that free motion of the radicals is inhibited when more than 25% of available sites are occupied. The ability to tune the mode of radical interactions and the subsequent effect on redox, electrical, and optical characteristics in a porous framework may lead to a class of structures with properties ideal for photoelectrochemistry or energy storage.

  19. Even free radicals should follow some rules: a guide to free radical research terminology and methodology.

    Science.gov (United States)

    Forman, Henry Jay; Augusto, Ohara; Brigelius-Flohe, Regina; Dennery, Phyllis A; Kalyanaraman, Balaraman; Ischiropoulos, Harry; Mann, Giovanni E; Radi, Rafael; Roberts, L Jackson; Vina, Jose; Davies, Kelvin J A

    2015-01-01

    Free radicals and oxidants are now implicated in physiological responses and in several diseases. Given the wide range of expertise of free radical researchers, application of the greater understanding of chemistry has not been uniformly applied to biological studies. We suggest that some widely used methodologies and terminologies hamper progress and need to be addressed. We make the case for abandonment and judicious use of several methods and terms and suggest practical and viable alternatives. These changes are suggested in four areas: use of fluorescent dyes to identify and quantify reactive species, methods for measurement of lipid peroxidation in complex biological systems, claims of antioxidants as radical scavengers, and use of the terms for reactive species.

  20. Structural functionality, catalytic mechanism modeling and molecular allergenicity of phenylcoumaran benzylic ether reductase, an olive pollen (Ole e 12) allergen

    Science.gov (United States)

    Jimenez-Lopez, Jose C.; Kotchoni, Simeon O.; Hernandez-Soriano, Maria C.; Gachomo, Emma W.; Alché, Juan D.

    2013-10-01

    Isoflavone reductase-like proteins (IRLs) are enzymes with key roles in the metabolism of diverse flavonoids. Last identified olive pollen allergen (Ole e 12) is an IRL relevant for allergy amelioration, since it exhibits high prevalence among atopic patients. The goals of this study are the characterization of (A) the structural-functionality of Ole e 12 with a focus in its catalytic mechanism, and (B) its molecular allergenicity by extensive analysis using different molecular computer-aided approaches covering (1) physicochemical properties and functional-regulatory motifs, (2) sequence analysis, 2-D and 3D structural homology modeling comparative study and molecular docking, (3) conservational and evolutionary analysis, (4) catalytic mechanism modeling, and (5) sequence, structure-docking based B-cell epitopes prediction, while T-cell epitopes were predicted by inhibitory concentration and binding score methods. Structural-based detailed features, phylogenetic and sequences analysis have identified Ole e 12 as phenylcoumaran benzylic ether reductase. A catalytic mechanism has been proposed for Ole e 12 which display Lys133 as one of the conserved residues of the IRLs catalytic tetrad (Asn-Ser-Tyr-Lys). Structure characterization revealed a conserved protein folding among plants IRLs. However, sequence polymorphism significantly affected residues involved in the catalytic pocket structure and environment (cofactor and substrate interaction-recognition). It might also be responsible for IRLs isoforms functionality and regulation, since micro-heterogeneities affected physicochemical and posttranslational motifs. This polymorphism might have large implications for molecular differences in B- and T-cells epitopes of Ole e 12, and its identification may help designing strategies to improve the component-resolving diagnosis and immunotherapy of pollen and food allergy through development of molecular tools.