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Sample records for carbonyl allylation propargylation

  1. Theoretical kinetic estimates for the recombination of hydrogen atoms with propargyl and allyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    Harding, L. B.; Klippenstein, S. J.

    2000-01-12

    Ab initio quantum chemical simulations are coupled with variational transition state theory in estimating rate constants for the H+C{sub 3}H{sub 3} and H+C{sub 3}H{sub 5} recombination reactions. The energy of interaction between the H atom and each of the radicals is evaluated at the CAS+1+2 level for the range of separations and relative orientations spanning the transition state region. An analytic representation of these interaction energies is then implemented in variable reaction coordinate transition state theory calculations of the high pressure limit recombination rate constant for temperatures ranging from 200 to 2000 K. For the propargyl reaction the overall addition rate is separated into contributions correlating with the initial formation of allene and propyne. These theoretical results are compared with the available experimental data as well as with corresponding theoretical estimates for the H+C{sub 2}H{sub 3} and H+C{sub 2}H{sub 5} reactions. The H+propargyl and H+allyl total recombination rates are remarkably similar, with both being greater than the H+vinyl and H+ethyl rates, due to the presence of twice as many addition channels.

  2. CuCl-Catalyzed Aerobic Oxidation of Allylic and Propargylic Alcohols to Aldehydes or Ketones with 1 : 1 Combination of Phenanthroline and Bipyridine as the Ligandst%CuCl-Catalyzed Aerobic Oxidation of Allylic and Propargylic Alcohols to Aldehydes or Ketones with 1 : 1 Combination of Phenanthroline and Bipyridine as the Ligandst

    Institute of Scientific and Technical Information of China (English)

    刘宇; 麻生明

    2012-01-01

    We developed a modified protocol for the oxidation of 2,3-allenyl alcohols using CuCI with l : 1 combination of phenanthroline and bipyridine as the catalyst. To further investigate the applicability of this system, other types of alcohols such as allylic and propargylic alcohols have been tested: we found that both allylic and propargylic alcohols may be oxidized to the corresponding aldehydes or ketones using molecular oxygen in air as the oxidant with moderate to excellent yields.

  3. Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls

    Science.gov (United States)

    Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D.; Krische, Michael J.

    2015-01-01

    The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo- and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k and 6m, respectively. Primary alcohols 2a, 2l and 2p were converted to the siloxy-crotylation products 3a, 3l and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

  4. Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls.

    Science.gov (United States)

    Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D; Krische, Michael J

    2015-10-14

    The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo-, and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k, and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k, and 6m, respectively. Primary alcohols 2a, 2l, and 2p were converted to the siloxy-crotylation products 3a, 3l, and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l, and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

  5. Green Synthesis and Regioselective Control of Sn/I2 Mediated Allylation of Carbonyl Compounds with Crotyl Halide in Water

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yan; ZHA,Zhang-Gen; ZHOU,Yu-Qing; WANG,Zhi-Yong

    2004-01-01

    @@ Barbier-type carbonyl allylation is particularly useful due to ease of operation and the availability and tractability of allylic substrates,[1] Metals such as indium, zinc and tin are often used as the mediator. Here we present a green approach toward the synthesis, that is, Sn/I2 mediated allylation of carbonyl compounds with crotyl halide in water.

  6. Double Conjugate Addition of Dithiols to Propargylic Carbonyl Systems To Generate Protected 1,3-Dicarbonyl Compounds

    NARCIS (Netherlands)

    Sneddon, Helen F.; Heuvel, Alexandra van den; Hirsch, Anna K.H.; Booth, Richard A.; Shaw, David M.; Gaunt, Matthew J.; Ley, Steven V.

    2006-01-01

    The work describes the efficient double conjugate addition of ethane and propane dithiols in the presence of sodium methoxide to a wide variety of propargylic carbonyl containing compounds. The products of these reactions are differentiated, 1,3-dicarbonyl systems useful for various synthesis progra

  7. Nano-Aluminum Powder Mediated Allylation of Carbonyl Compounds in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    YUAN Shi-Zhen; LIU Jin

    2008-01-01

    A new and effective Barbier-Grignard allylation of aldehydes or ketones has been carried out with nano-aluminum powder in aqueous 0.1 mol·L-1 NH4Cl (aq.) under an atmosphere of nitrogen. Aromatic carbonyl compounds gave homoallylic alcohols in good yields. The effectiveness of reaction was strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic carbonyl compounds proceeded in low yields. The dominant stereoisomer was an erythro-isomer when an ortho-hydroxyl carbonyl compound was reacted under such a reaction condition.

  8. α-Regioselective Barbier Reaction of Carbonyl Compounds and Allyl Halides Mediated by Praseodymium.

    Science.gov (United States)

    Wu, San; Li, Ying; Zhang, Songlin

    2016-09-01

    The first utility of praseodymium as a mediating metal in the Barbier reaction of carbonyl compounds with allyl halides was reported in this paper. In contrast to the traditional metal-mediated or catalyzed Barbier reactions, exclusive α-adducts were obtained in this one-pot reaction with a broad scope of substrates and feasible reaction conditions. PMID:27490708

  9. Hydroxymethylation beyond Carbonylation: Enantioselective Iridium-Catalyzed Reductive Coupling of Formaldehyde with Allylic Acetates via Enantiotopic π-Facial Discrimination.

    Science.gov (United States)

    Garza, Victoria J; Krische, Michael J

    2016-03-23

    Chiral iridium complexes modified by SEGPHOS catalyze the 2-propanol-mediated reductive coupling of branched allylic acetates 1a-1o with formaldehyde to form primary homoallylic alcohols 2a-2o with excellent control of regio- and enantioselectivity. These processes, which rely on enantiotopic π-facial discrimination of σ-allyliridium intermediates, represent the first examples of enantioselective formaldehyde C-C coupling beyond aldol addition. PMID:26958737

  10. Ruthenium-BINAP Catalyzed Alcohol C-H tert-Prenylation via 1,3-Enyne Transfer Hydrogenation: Beyond Stoichiometric Carbanions in Enantioselective Carbonyl Propargylation.

    Science.gov (United States)

    Nguyen, Khoa D; Herkommer, Daniel; Krische, Michael J

    2016-04-27

    The chiral ruthenium complex formed in situ from (TFA)2Ru(CO)(PPh3)2 and (R)-BINAP is found to catalyze the enantioselective C-C coupling of diverse primary alcohols with the 1,3-enyne, TMSC≡CC(Me)═CH2, to form secondary homopropargyl alcohols bearing gem-dimethyl groups. All reagents for this byproduct-free coupling are inexpensive and commercially available, making this protocol a practical alternative to stoichiometric carbanions in enantioselective carbonyl reverse prenylation. PMID:27079149

  11. Allylation of Aromatic Aldehyde under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yu-Mei; JIA,Xue-Feng; WANG,Jin-Xian

    2004-01-01

    @@ Allylation of carbonyl compounds is one of the most interesting processes for the preparation of homoallylic alcohols. Over the past few decades, many reagents have been developed for such reactions[1~3]. In this paper, we first report allylic zinc reagent 1, which can be prepared from zinc dust and allyl bromide conveniently in THF, and reacted with aromatic aldehyde to give homo-allylic alcohols under microwave irradiation.

  12. Ruthenium(II) carbonyl complexes bearing quinoline-based NNO tridentate ligands as catalyst for one-pot conversion of aldehydes to amides and o-allylation of phenols

    Science.gov (United States)

    Manikandan, R.; Prakash, G.; Kathirvel, R.; Viswanathamurthi, P.

    2013-12-01

    Six new octahedral ruthenium(II) carbonyl complexes having the general molecular formula [RuCl(CO)(B)L1-2] (B = PPh3, AsPh3 or py; L1-2 = quinoline based NNO ligand) were synthesized. The quinoline based ligands behave as monoanionic tridentate donor and coordinated to ruthenium via ketoenolate oxygen, azomethine nitrogen and quinoline nitrogen. The composition of the complexes has been established by elemental analysis and spectral methods (FT-IR, electronic, 1H NMR, 13C NMR, 31P NMR and ESI-Mass). The complexes were used as efficient catalysts for one-pot conversion of various aldehydes to their corresponding primary amides in presence of NH2OH·HCl and NaHCO3. The effect of catalyst loading and reaction temperature on catalytic activity of the ruthenium(II) carbonyl complexes were also investigated. The synthesized complexes also possess good catalytic activity for the o-allylation of phenols in the presence of K2CO3 under mild conditions. The complexes afforded branched allyl aryl ethers according to a regioselective reaction.

  13. Transition metal catalysed Grignard-like allylic activation across tetragonal tin(II) oxide

    Indian Academy of Sciences (India)

    Pradipta Sinha; Moloy Banerjee; Abhijit Kundu; Sujit Roy

    2002-08-01

    The reaction of allyl halide and a carbonyl compound under the aegis of tetragonal tin(II) oxide and catalytic 8, 10 metal complexes provides the corresponding homoallylic alcohol, via a novel allyl tin intermediate.

  14. Allyl 4-hydroxyphenyl carbonate

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Flores Ahuactzin

    2009-07-01

    Full Text Available The title molecule, C10H10O4, is a functionalized carbonate used in the synthetic route to organic glasses. The central CH fragment of the allyl group is disordered over two positions, with occupancies in a 0.758 (10:0.242 (10ratio. This disorder reflects the torsional flexibility of the oxygen–allyl group, although both disordered parts present the expected anticlinal conformation, with O—CH2—CH=CH2 torsion angles of −111 (2 and 119.1 (4°. The crystal structure is based on chains parallel to [010], formed by O...H—O hydrogen bonds involving hydroxyl and carbonyl groups as donors and acceptors, respectively. The molecular packing is further stabilized by two weak C—H...π contacts from the benzene ring of the asymmetric unit with two benzene rings of neighboring molecules.

  15. Reactions of unsaturated compounds. CXXIV. Claisen rearrangement of allyl and propargyloxydienyl phosphonates

    Energy Technology Data Exchange (ETDEWEB)

    Dangyan, Yu.M.; Tirakyan, M.R.; Panosyan, G.A.; Badanyan, Sh.O.

    1986-12-20

    O,O-Dialkyl-1-ethylidene-2-allyl(propargyl)oxy-2-butenyl phosphonates have been obtained from vinylallenyl phosphonates and undergo thermal Claisen rearrangement to form highly unsaturated ketophosphonates. Comprehensive coupling constant and chemical shift figures from an NMR analysis are given.

  16. Propargylation of arabinogalactan with propargyl halides--a facile route to new functionalized biopolymers.

    Science.gov (United States)

    Grischenko, Lyudmila A; Parshina, Lidiya N; Kanitskaya, Lyudmila V; Larina, Lyudmila I; Novikova, Lyubov N; Trofimov, Boris A

    2013-07-19

    New arabinogalactan propargyl ethers with degree of substitution (DS) up to 2.8 have been obtained by propargylation of arabino-3,6-galactan (AG) with propargyl bromide (PB) in the two-phase system 30-60% КОН aqueous solution/toluene in the presence of triethylbenzylammonium chloride (TEBAС) or without catalyst (ambient temperature, 1-24 h) in 20-87% yields. The highest yields have been reached using TEBAС as phase-transfer catalyst, though the non-catalytic version proves to be also efficient (DS 2.8, 70% yield). The propargylation of AG is less effective in the systems MОН (M=Na, K)/DMSO. DS of propargyl AG reaches 1.8 (70% yield) when propargyl chloride is used as propargylating agent, while with PB under the same conditions DS value does not exceed 0.4-0.6, the yields being 44-65%. Under the action of t-BuOK/DMSO system, the AG propargyl ethers have been isomerized to the corresponding unstable allenyl ethers. AG propargyl ethers with DS 2.0 have been almost exhaustively metallated with Ag2O/NH3 system to give AG-Ag acetylides derivatives with Ag/C≡C ratio equaling 0.95.

  17. Rotational Spectrum of Propargyl Alcohol Dimer

    Science.gov (United States)

    Mani, Devendra; Arunan, E.

    2013-06-01

    Propargyl alcohol is a molecule of interest to astrophysics as well as combustion studies. Rotational-tunneling spectra of propargyl alcohol monomer is well known and shows that the molecule exists in gauche form. Recently we reported microwave spectra of Ar...propargyl alcohol complex. Propargyl alcochol exists in gauche form in the complex as well. In this study we have recorded pure rotational spectra of propargyl alcohol dimer between 4-13 GHz range.A total of 47 transitions, 24 a-type, 16 b-type and 7 c-type, have been observed and fitted with semi rigid rotor asymmetric top hamiltonian. The fitted rotational constants are: A = 2321.83323(47) MHz, B = 1150.47726(24) MHz and C = 1124.89000(20) MHz. The standard deviation for the fit is 2.5 kHz. The experimental rotational constants are very close to the structure predicted by ab-initio calculations in which two gauche-propargyl alcohol moieties are in three point contact stabilized by O-H...O, O-H...pi and C-H...pi interactions. Few transitions for duterated isotopologues of the dimer have also been observed and search for the remaining transitions is in progress. Details will be presented in the talk. E. Hirota,J. Mol. Spectrosc. 26 (1968) 335-350. J.C. Pearson, B.J. Drouin, J. Mol. Spectrosc. 234 (2005) 149-156. D. Mani, E. Arunan, ChemPhysChem 14 (2013) 754-763.

  18. Synthesis of acrylic and allylic bifunctional cross-linking monomers derived from PET waste

    Science.gov (United States)

    Cruz-Aguilar, A.; Herrera-González, A. M.; Vázquez-García, R. A.; Navarro-Rodríguez, D.; Coreño, J.

    2013-06-01

    An acrylic and two novel allylic monomers synthesized from bis (hydroxyethyl) terephthalate, BHET, are reported. This was obtained by glycolysis of post-consumer PET with boiling ethylene glycol. The bifunctional monomer bis(2-(acryloyloxy)ethyl) terephthalate was obtained from acryloyl chloride, while the allylic monomers 2-(((allyloxi)carbonyl)oxy) ethyl (2-hydroxyethyl) terephthalate and bis(2-(((allyloxi)carbonyl)oxy)ethyl) terephthalate, from allyl chloroformate. Cross-linking was studied in bulk polymerization using two different thermal initiators. Monomers were analyzed by means of 1H NMR and the cross-linked polymers by infrared spectroscopy. Gel content higher than 90% was obtained for the acrylic monomer. In the case of the mixture of the allylic monomers, the cross-linked polymer was 80 % using BPO initiator, being this mixture 24 times less reactive than the acrylic monomer.

  19. Platinum-Catalyzed Friedel-Crafts-Type C-H Coupling-Allylic Amination Cascade to Synthesize 3,4-Fused Tricyclic Indoles.

    Science.gov (United States)

    Suzuki, Yuta; Tanaka, Yuito; Nakano, Shun-ichi; Dodo, Kosuke; Yoda, Natsumi; Shinohara, Ken-Ichi; Kita, Kazuko; Kaneda, Atsushi; Sodeoka, Mikiko; Hamada, Yasumasa; Nemoto, Tetsuhiro

    2016-03-18

    A novel platinum-catalyzed cascade cyclization reaction was developed by intramolecular Friedel-Crafts-type C-H coupling of aniline derivatives with a propargyl carbonate unit-allylic amination sequence. Treatment of various propargyl carbonates tethered to meta-aniline derivatives with a Pt(dba)3/DPEphos catalyst system afforded the corresponding 3,4-fused tricyclic 3-alkylidene indolines in 42-99% yield, which were transformed into 3,4-fused indole derivatives by reaction with trifluoroacetic acid. The reaction products exhibited antiproliferative activities against cancer cells, but not normal cells, revealing the potential usefulness of this reaction for medicinal chemistry. PMID:26833557

  20. Propargyl-functional aliphatic polycarbonate obtained from carbon dioxide and glycidyl propargyl ether.

    Science.gov (United States)

    Hilf, Jeannette; Frey, Holger

    2013-09-01

    The synthesis of propargyl-functional poly(carbonate)s with different content of glycidyl propargyl ether (GPE) units is achieved via the copolymerization of propargyl glycidyl ether and carbon dioxide. A new type of functional poly(carbonate) synthesized directly from CO(2) and the glycidyl ether is obtained. The resulting polymers show moderate polydispersities in the range of 1.6-2.5 and molecular weights in the range of 7000-10 500 g mol(-1). The synthesized copolymers with varying number of alkyne functionalities and benzyl azide are used for the copper-catalyzed Huisgen-1,3-dipolar addition. Moreover, the presence of vicinal alkyne groups opens a general pathway to produce functional aliphatic poly(carbonate)s from a single polymer scaffold.

  1. Reactions of a Ruthenium Complex with Substituted N-Propargyl Pyrroles.

    Science.gov (United States)

    Chia, Pi-Yeh; Huang, Shou-Ling; Liu, Yi-Hong; Lin, Ying-Chih

    2016-04-01

    In an investigation into the chemical reactions of N-propargyl pyrroles 1 a-c, containing aldehyde, keto, and ester groups on the pyrrole ring, with [Ru]-Cl ([Ru]=Cp(PPh3 )2 Ru; Cp=C5 H5 ), an aldehyde group in the pyrrole ring is found to play a crucial role in stimulating the cyclization reaction. The reaction of 1 a, containing an aldehyde group, with [Ru]-Cl in the presence of NH4 PF6 yields the vinylidene complex 2 a, which further reacts with allyl amine to give the carbene complex 6 a with a pyrrolizine group. However, if 1 a is first reacted with allyl amine to yield the iminenyne 8 a, then the reaction of 8 a with [Ru]-Cl in the presence of NH4 PF6 yields the ruthenium complex 9 a, containing a cationic pyrrolopyrazinium group, which has been fully characterized by XRD analysis. These results can be adequately explained by coordination of the triple bond of the propargyl group to the ruthenium metal center first, followed by two processes, that is, formation of a vinylidene intermediate or direct nucleophilic attack. Additionally, the deprotonation of 2 a by R4 NOH yields the neutral acetylide complex 3 a. In the presence of NH4 PF6 , the attempted alkylation of 3 a resulted in the formation the Fischer-type amino-carbene complex 5 a as a result of the presence of NH3 , which served as a nucleophile. With KPF6 , the alkylation of 3 a with ethyl and benzyl bromoacetates afforded the disubstituted vinylidene complexes 10 a and 11 a, containing ester groups, which underwent deprotonation reactions to give the furyl complexes 12 a and 13 a, respectively. For 13 a, containing an O-benzyl group, subsequent 1,3-migration of the benzyl group was observed to yield product 14 a with a lactone unit. Similar reactivity was not observed for the corresponding N-propargyl pyrroles 1 b and 1 c, which contained keto and ester groups, respectively, on the pyrrole ring. PMID:26865008

  2. Cu/Fe-cocatalyzed Meyer-Schuster-like rearrangement of propargylic amines: direct access to E-β-aminoacryaldehydes.

    Science.gov (United States)

    Chen, Ming; Peng, Jiangling; Mao, Tingting; Huang, Jinbo

    2014-12-19

    A simple and efficient method for the synthesis of β-aminoacryaldehydes via Cu(OAc)2·H2O and FeCl3 cocatalyzed Meyer-Schuster-Like rearrangement of propargylic amines was developed. The reactions proceed selectively as the E-isomers in generally good yields under aerobic conditions, and are compatible with a broad range of functional groups. This method combines C-N bond cleavage as well as the N-aryl group migration and provides a practical and mild synthetic approach to α,β-unsaturated carbonyl compounds, which are useful precursors in a variety of functional group transformations. PMID:25453833

  3. BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

    International Nuclear Information System (INIS)

    Propargyl alcohol (CHCCH2OH) is a known stable isomer of the propenal (CH2CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm–1. Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C6H6) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C3H3) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C6H6 in the interstellar icy mantles

  4. Absolute photoionization cross-section of the propargyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Savee, John D.; Welz, Oliver; Taatjes, Craig A.; Osborn, David L. [Sandia National Laboratories, Combustion Research Facility, Livermore, California 94551 (United States); Soorkia, Satchin [Institut des Sciences Moleculaires d' Orsay, Universite Paris-Sud 11, Orsay (France); Selby, Talitha M. [Department of Chemistry, University of Wisconsin, Washington County Campus, West Bend, Wisconsin 53095 (United States)

    2012-04-07

    Using synchrotron-generated vacuum-ultraviolet radiation and multiplexed time-resolved photoionization mass spectrometry we have measured the absolute photoionization cross-section for the propargyl (C{sub 3}H{sub 3}) radical, {sigma}{sub propargyl}{sup ion}(E), relative to the known absolute cross-section of the methyl (CH{sub 3}) radical. We generated a stoichiometric 1:1 ratio of C{sub 3}H{sub 3} : CH{sub 3} from 193 nm photolysis of two different C{sub 4}H{sub 6} isomers (1-butyne and 1,3-butadiene). Photolysis of 1-butyne yielded values of {sigma}{sub propargyl}{sup ion}(10.213 eV)=(26.1{+-}4.2) Mb and {sigma}{sub propargyl}{sup ion}(10.413 eV)=(23.4{+-}3.2) Mb, whereas photolysis of 1,3-butadiene yielded values of {sigma}{sub propargyl}{sup ion}(10.213 eV)=(23.6{+-}3.6) Mb and {sigma}{sub propargyl}{sup ion}(10.413 eV)=(25.1{+-}3.5) Mb. These measurements place our relative photoionization cross-section spectrum for propargyl on an absolute scale between 8.6 and 10.5 eV. The cross-section derived from our results is approximately a factor of three larger than previous determinations.

  5. Kinetic Studies that Evaluate the Solvolytic Mechanisms of Allyl and Vinyl Chloroformate Esters

    Directory of Open Access Journals (Sweden)

    Malcolm J. D'Souza

    2013-04-01

    Full Text Available At 25.0 °C the specific rates of solvolysis for allyl and vinyl chloroformates have been determined in a wide mix of pure and aqueous organic mixtures. In all the solvents studied, vinyl chloroformate was found to react significantly faster than allyl chloroformate. Multiple correlation analyses of these rates are completed using the extended (two-term Grunwald-Winstein equation with incorporation of literature values for solvent nucleophilicity (NT and solvent ionizing power (YCl. Both substrates were found to solvolyze by similar dual bimolecular carbonyl-addition and unimolecular ionization channels, each heavily dependent upon the solvents nucleophilicity and ionizing ability.

  6. Rotational Spectrum of Ar...PROPARGYL Alcohol Complex

    Science.gov (United States)

    Mani, Devendra; Shahi, Abhishek; Arunan, E.

    2012-06-01

    Pure rotational spectrum for Ar...Propargyl alcohol complex has been observed and fitted. Fitted rotational constants for the complex are : A=4346.17307(90) MHz, B=1617.15317(19)MHz and C= 1245.42065(15) MHz. These rotational constants are very close to the ab-initio rotational constants for the geometry, in which propargyl alcohol exists in gauche conformation and Ar interacts with both, the hydroxyl group and the acetylenic group of propargyl alcohol. Rotational spectrum of deuterated isotopologue (-OD) of the complex further confirms the existence of the above mentioned geometry. In previous studies tunneling frequency corresponding to -OH tunneling motion in propargyl alocohol monomer was determined to be 652.4 GHz and for -OD tunneling motion in mono-deuterated species, it was 213.5 GHz. In Ar...Propargyl alcohol complex also, a-type and c-dipole transitions show tunneling splitting. In the parent complex, for a-type transitions, tunneling splitting was 10 KHz and for c-type transitions (c-dipole of the complex is in the same direction as in propargyl alcohol monomer, and it is antisymmetric with respect to OH tunneling motion in both monomer and the complex), it was 2.59 MHz. In deuterated complex (OD) splitting was not resolvable for a-type transitions while for c-type it reduces to 900 KHz. Search for C-13 isotopologues is in progress. Moreover, propargyl alcohol offers several possibilities for H-bonding and we are planning to study its complexes with water in near future. Results will be presented in the talk. E. Hirota,J. Mol. Spectrosc. 26 (1968) 335-350. J.C. Pearson, B.J. Drouin, J. Mol. Spectrosc. 234 (2005) 149-156.

  7. Sulfoxide-Directed Metal-Free ortho-Propargylation of Aromatics and Heteroaromatics.

    Science.gov (United States)

    Eberhart, Andrew J; Shrives, Harry J; Álvarez, Estela; Carrër, Amandine; Zhang, Yuntong; Procter, David J

    2015-05-11

    A sulfoxide-directed, metal-free ortho-propargylation of aromatics and heteroaromatics exploits intermolecular delivery of a propargyl nucleophile to sulfur followed by an intramolecular relay to carbon. The operationally simple cross-coupling procedure is general, regiospecific with regard to the propargyl nucleophile, and shows complete selectivity for products of ortho-propargylation over allenylation. The use of secondary propargyl silanes allows metal-free ortho-coupling to form carbon-carbon bonds between aromatic and heteroaromatic rings and secondary propargylic centres. The 'safety-catch' nature of the sulfoxide directing group is illustrated in a selective, iterative double cross-coupling process. The products of propargylation are versatile intermediates and they have been readily converted into substituted benzothiophenes.

  8. The allylic chalcogen effect in olefin metathesis

    Directory of Open Access Journals (Sweden)

    Yuya A. Lin

    2010-12-01

    Full Text Available Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications.

  9. The allylic chalcogen effect in olefin metathesis

    Science.gov (United States)

    Lin, Yuya A

    2010-01-01

    Summary Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications. PMID:21283554

  10. Interplay of metal-allyl and metal-metal bonding in dimolybdenum allyl complexes.

    Energy Technology Data Exchange (ETDEWEB)

    Trovitch, R. J.; John, K. D.; Martin, R. L.; Obrey, S. J.; Sattelberger, A. P.; Scott, B. L.; Baker, R. T.; LANL; Univ. of Ottawa

    2009-01-01

    Addition of PMe{sub 3} to Mo{sub 2}(allyl){sub 4} afforded Mo{sub 2}(allyl){sub 4}(PMe{sub 3}){sub 2}, in which two of the allyl groups adopt an unprecedented {mu}{sub 2}-{eta}{sup 1}, {eta}{sup 3} bonding mode; theoretical studies elucidate the roles of the {sigma}- and {pi}-donor ligands in the interplay of metal-allyl and metal-metal bonding.

  11. Synthesis of Propargyl-Terminated Heterobifunctional Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Wen Zhong

    2010-10-01

    Full Text Available Novel propargyl-ended heterobifunctional poly(ethylene glycol (PEG derivatives with hydroxyl, carboxyl, mercapto or hydrazide end groups were synthesized with simplicity yet high efficiency. PEG (Mw = 3500 Da with an α-hydroxyl group and an ω-carboxyl was used as the starting polymer. The carboxyl group of the bifunctional PEG was modified into a propargyl, then carboxyl, mercapto or hydrazide groups were introduced to the other end of the bifunctional PEG by modifying the bifunctional PEG’s hydroxyl group with succinic anhydride, cysteamide or tert-butyl carbazate, respectively. This method can be useful to the development of PEG-based bioconjugates for a variety of biomedical applications.

  12. Photofragment Translational Spectroscopy of Propargyl Radicals at 248 nm

    Energy Technology Data Exchange (ETDEWEB)

    Goncher, S.J.; Moore, D.T.; Sveum, N.E.; Neumark, D.M.

    2007-12-21

    The photodissociation of propargyl radical, C{sub 3}H{sub 3}, and its perdeuterated isotopolog was investigated using photofragment translational spectroscopy. Propargyl radicals were produced by 193 nm photolysis of allene entrained in a molecular beam expansion, and then photodissociated at 248 nm. photofragment time-of-flight spectra were measured at a series of laboratory angles using electron impact ionization coupled to a mass spectrometer. Data for ion masses corresponding to C{sub 3}H{sub 2}{sup +}, C{sub 3}H{sup +}, C{sub 3}{sup +}, and the analogous deuterated species show that both H and H{sub 2} loss occur. The translational energy distributions for these processes have average values = 5.7 and 15.9 kcal/mol, respectively, and are consistent with dissociation on the ground state following internal conversion, with no exit barrier for H loss but a tight transition state for H{sub 2} loss. The translational energy distribution for H atom loss is similar to that in previous work on propargyl in which the H atom, rather than the heavy fragment, was detected. The branching ratio for H loss/H{sub 2} loss was determined to be 97.6/2.4 {+-} 1.2, in good agreement with RRKM results.

  13. Synthesis of diversely substituted 2-(furan-3-yl)acetates from allenols through cascade carbonylations.

    Science.gov (United States)

    He, Yan; Zhang, Xinying; Fan, Xuesen

    2015-11-21

    Novel synthesis of diversely substituted 2-(furan-3-yl)acetates via palladium-catalyzed one-pot multi-component reactions of allenols, aryl iodides, alcohols, and carbon monoxide has been developed. Notably, the formation of the title compounds features a cascade process combining carbonylation of aryl iodide, alcohoxyl carbonylation of the in situ formed allyl palladium complex, and intramolecular condensation of the α-hydroxyl enone intermediate. Moreover, the 2-(furan-3-yl)acetates obtained herein were found to be ready intermediates for the construction of the biologically significant naphtho[1,2-b]furan-5-ol scaffold. PMID:26399394

  14. Highly enantio- and diastereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with allyl ketones

    KAUST Repository

    Tong, Guanghu

    2013-05-17

    The asymmetric allylic alkylation of Morita-Baylis-Hillman (MBH) carbonates with allyl ketones has been developed. The α-regioselective alkylation adducts, containing a hexa-1,5-diene framework with important synthetic value, were achieved in up to 83% yield, >99% ee, and 50:1 dr by using a commercially available Cinchona alkaloid as the catalyst. From the allylic alkylation adduct, a cyclohexene bearing two adjacent chiral centers was readily prepared. © 2013 American Chemical Society.

  15. Cationic ruthenium-cyclopentadienyl-diphosphine complexes as catalysts for the allylation of phenols with allyl alcohol: relation between structure and catalytic performance in O- vs. C-allylation

    NARCIS (Netherlands)

    van Rijn, J.A.; Lutz, M.; von Chrzanowski, L.S.; Spek, A.L.; Bouwman, E.; Drent, E.

    2009-01-01

    A new catalytic method has been investigated to obtain either O- or C-allylated phenolic products using allyl alcohol or diallyl ether as the allyl donor. With the use of new cationic ruthenium(II) complexes as catalyst, both reactions can be performed with good selectivity. Active cationic Ru(II) c

  16. N-Allylation of amines with allyl acetates using chitosan-immobilized palladium

    Science.gov (United States)

    A simple procedure for N-Allylation of allyl Acetates has been developed using a biodegradable and easily recyclable heterogeneous chitosan-supported palladium catalyst. The general methodology, applicable to wide range of substrates, has sustainable features that include a ligan...

  17. Compound list: allyl alcohol [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available allyl alcohol AA 00010 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/allyl_alcohol....Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/allyl_alcohol...dbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Repeat/allyl_alcohol.Rat.in_vivo.Liver.Repeat.zip ftp:/.../ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Kidney/Single/allyl_alcohol.Rat.in_vivo.Kidney....Single.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Kidney/Repeat/allyl_alcohol.Rat.in_vivo.Kidney.Repeat.zip ...

  18. Cross-coupling of propargylated arabinogalactan with 2-bromothiophene.

    Science.gov (United States)

    Parshina, Lidiya N; Grishchenko, Lyudmila A; Larina, Lyudmila I; Novikova, Lyubov N; Trofimov, Boris A

    2016-10-01

    Novel pharmacologically prospective derivatives of arabinogalactan (a polysaccharide from larch wood) containing acetylenic and thiophene moieties have been obtained in up to 90% yield by cross-coupling of propargylic ethers of arabinogalactan with 2-bromothiophene. The reaction proceeds in the presence of the catalytic system Pd(Ph3P)4/CuBr/LiBr and piperidine in DMSO at 80-85°С. An advantageous feature of the synthesis is that it requires 5-25 times lesser catalytic loading than in common Sonogashira protocols thus making the reaction particularly beneficial to synthesize pharmaceutically-oriented polysaccharides. PMID:27312616

  19. Enantioselective synthesis of fluorinated branched allylic compounds via Ir-catalyzed allylations of functionalized fluorinated methylene derivatives.

    Science.gov (United States)

    Zhang, Hongbo; Chen, Jiteng; Zhao, Xiao-Ming

    2016-08-14

    Enantioselective introduction of the functionalized monofluorinated methylenes into the allylic fragment under Ir catalysis has been realized, which gave the fluorinated branched allyl products in good to high yields with excellent regio- and enantioselectivities. PMID:27383920

  20. Tether-directed synthesis of highly substituted oxasilacycles via an intramolecular allylation employing allylsilanes

    Directory of Open Access Journals (Sweden)

    Cox Liam R

    2007-02-01

    Full Text Available Abstract Background Using a silyl tether to unite an aldehyde electrophile and allylsilane nucleophile into a single molecule allows a subsequent Lewis-acid-mediated allylation to proceed in an intramolecular sense and therefore receive all the benefits associated with such processes. However, with the ability to cleave the tether post allylation, a product that is the result of a net intermolecular reaction can be obtained. In the present study, four diastereoisomeric β-silyloxy-α-methyl aldehydes, which contain an allylsilane tethered through the β-carbinol centre, have been prepared, in order to probe how the relative configuration of the two stereogenic centres affects the efficiency and selectivity of the intramolecular allylation. Results Syn-aldehydes, syn-4a and syn-4b, both react poorly, affording all four possible diastereoisomeric oxasilacycle products. In contrast, the anti aldehydes anti-4a and anti-4b react analogously to substrates that lack substitution at the α-site, affording only two of the four possible allylation products. Conclusion The outcome of the reaction with anti-aldehydes is in accord with reaction proceeding through a chair-like transition state (T.S.. In these systems, the sense of 1,3-stereoinduction can be rationalised by the aldehyde electrophile adopting a pseudoaxial orientation, which will minimise dipole-dipole interactions in the T.S. The 1,4-stereoinduction in these substrates is modest and seems to be modulated by the R substituent in the starting material. In the case of the syn-substrates, cyclisation through a chair T.S. is unlikely as this would require the methyl substituent α to the reacting carbonyl group to adopt an unfavourable pseudoaxial position. It is therefore proposed that these substrates react through poorly-defined T.S.s and consequently exhibit essentially no stereoselectivity.

  1. Kinetic Resolution of Racemic and Branched Monosubstituted Allylic Acetates by a Ruthenium-Catalyzed Regioselective Allylic Etherification.

    Science.gov (United States)

    Shinozawa, Toru; Terasaki, Shou; Mizuno, Shota; Kawatsura, Motoi

    2016-07-01

    We demonstrated the kinetic resolution of racemic and branched monosubstituted allylic acetates by a ruthenium-catalyzed regioselective allylic etherification. The reaction was effectively catalyzed by the chiral ruthenium catalyst, which was generated by [RuCl2(p-cymene)]2 and (S,S)-iPr-pybox and a catalytic amount of TFA, and both the allylic etherification product and recovered allylic acetate were obtained as an enantiomerically enriched form with up to a 103 s value. PMID:27276556

  2. Allylic Nitro Compounds as Nitrite Donors

    OpenAIRE

    Chakrapani, Harinath; Gorczynski, Michael J.; King, S Bruce

    2006-01-01

    Allylic nitro compounds were synthesized and evaluated as organic sources of nitrite and nitric oxide. Unactivated allylic nitro compounds do not spontaneously release nitrite and nucleophile promoted nitrite release is slow. However, 2-(nitromethyl)-cyclohex-1-ene-3-one spontaneously dissociates in buffer (pH = 7.4) to release nitrite with a kobs = 1.6 × 10−5 s−1. In the presence of L-cysteine, this compound rapidly yields nitrite and reacts with hemoglobin similarly to sodium nitrite. Struc...

  3. 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.

  4. Palladium Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Fristrup, Peter

    2011-01-01

    The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C...

  5. Electrocatalytic activity of Ni-doped nanoporous carbons in the electrooxidation of propargyl alcohol

    OpenAIRE

    García-Cruz, Leticia; Sáez, Alfonso; Ovín Ania, María Concepción; Solla-Gullón, José; Thiemann, Thies; Iniesta, Jesús; Montiel, Vicente

    2014-01-01

    Herein, we explore the immobilization of nickel on various carbon supports and their application as electrocatalysts for the oxidation of propargyl alcohol in alkaline medium. In comparison with massive and nanoparticulated nickel electrode systems, Ni-doped nanoporous carbons provided similar propargyl alcohol conversions for very low metallic contents. Nanoparticulated Ni on various carbon supports gave rise to the highest electrocatalytic activity in terms of product selectivity, with a cl...

  6. Origins of Stereoselectivities in Chiral Phosphoric Acid-Catalyzed Allylborations and Propargylations of Aldehydes

    OpenAIRE

    Wang, Hao; Jain, Pankaj; Antilla, Jon C.; Houk, K. N.

    2013-01-01

    The chiral BINOL-phosphoric acid catalyzed allylboration and propargylation reactions are studied with density functional theory (B3LYP and B3LYP-D3). Two different models were recently proposed for these reactions by Goodman and our group, respectively. In Goodman's model for allylborations, the catalyst interacts with the boronate pseudo-axial oxygen. By contrast, our model for propargylations predicts that the catalyst interacts with the boronate pseudo-equatorial oxygen. In both models, t...

  7. Validation of protein carbonyl measurement

    DEFF Research Database (Denmark)

    Augustyniak, Edyta; Adam, Aisha; Wojdyla, Katarzyna;

    2015-01-01

    Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial...

  8. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction

    Directory of Open Access Journals (Sweden)

    Thomas Zeuch

    2013-11-01

    Full Text Available Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn’s largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br, allyl chloride (C3H5Cl, and 1,5-hexadiene (CH2CH(CH22CHCH2 at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re- combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re- combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.

  9. Total Synthesis of (-)-Spinosyn A via Carbonylative Macrolactonization.

    Science.gov (United States)

    Bai, Yu; Shen, Xingyu; Li, Yong; Dai, Mingji

    2016-08-31

    Spinosyn A (1), a complex natural product featuring a unique 5,6,5,12-fused tetracyclic core structure, is the major component of spinosad, an organic insecticide and an FDA-approved agent used worldwide. Herein, we report an efficient total synthesis of (-)-spinosyn A with 15 steps in the longest linear sequence and 23 steps total from readily available compounds 14 and 23. The synthetic approach features several important catalytic transformations including a chiral amine-catalyzed intramolecular Diels-Alder reaction to afford 22 in excellent diastereoselectivity, a one-step gold-catalyzed propargylic acetate rearrangement to convert 28 to α-iodoenone 31, an unprecedented palladium-catalyzed carbonylative Heck macrolactonization to form the 5,12-fused macrolactone in one step, and a gold-catalyzed Yu glycosylation to install the challenging β-forosamine. This total synthesis is highly convergent and modular, thus offering opportunities to synthesize spinosyn analogues in order to address the emerging cross-resistance problems. PMID:27510806

  10. SYNTHESIS OF ALLYL PHENYL ETHER AND CLAISEN REARRANGEMENT

    Directory of Open Access Journals (Sweden)

    Gagik Torosyan

    2011-12-01

    Full Text Available It has been established the possibility for phenol allylation on natural zeolites and them analogs. Here is demonstrated the synthesis of allyl phenol, which has wide industrial applications. The offered method in comparison with the traditional methods has more advantages – higher selectivity, smaller material and power resources consumption. It has been obtained the mixture of allylating phenols (30% in general with allyl phenyl ether (1 with 80% yields. At 600 K is obtained allylphenyl ether, at 700 K beginning the formation of allyl phenols, which is the result of direct C-allylation of the aromatic ring. It has been investigated the possibility of Claisen rearrangement in the same conditions. All of that are established by gas-liquid chromatography and liquid chromatography data.

  11. Cp*Co(III)-Catalyzed Dehydrative C-H Allylation of 6-Arylpurines and Aromatic Amides Using Allyl Alcohols in Fluorinated Alcohols.

    Science.gov (United States)

    Bunno, Youka; Murakami, Nanami; Suzuki, Yudai; Kanai, Motomu; Yoshino, Tatsuhiko; Matsunaga, Shigeki

    2016-05-01

    Cp*Co(III)-catalyzed C-H allylation of various aromatic C-H bonds using allyl alcohols as allylating reagents is described. Improved reaction conditions using fluorinated alcohol solvents afforded efficient directed C-H allylation of 6-arylpurines, benzamides, and a synthetically useful Weinreb amide with good functional group compatibility.

  12. Resonance Raman spectrum of the allyl-d5 radical and the force field analysis of the allyl radical

    Science.gov (United States)

    Liu, Xianming; Getty, James D.; Kelly, Peter B.

    1993-08-01

    Resonance Raman spectra of the allyl-d5 radical have been obtained with excitation between 247 and 223 nm. Analysis of the spectra yields the first observation of fundamental frequencies, nu4, nu5, and nu7 and overtone frequencies 2nu9, 2nu10, and 2nu12. The new vibrational data are combined with previously observed frequencies of allyl-h5 and allyl-d5 radical to produce the force field analysis for the allyl radical. This study suggests reassignment of several previously observed infrared (IR) bands. Experimental frequencies and assignments for allyl-h5 and allyl-d5 are compared with results from ab initio calculations. Force constants obtained in the present work are compared with the force constants of other sp2 hybridization molecules such as benzene, allene, and ethylene.

  13. Temperature-controlled redox-neutral ruthenium(ii)-catalyzed regioselective allylation of benzamides with allylic acetates.

    Science.gov (United States)

    Manikandan, Rajendran; Jeganmohan, Masilamani

    2016-08-10

    Substituted aromatic amides reacted efficiently with allylic acetates in the presence of a cationic ruthenium complex in ClCH2CH2Cl at room temperature providing ortho allylated benzamides in a highly regioselective manner without any oxidant and base. The whole catalytic reaction occurred in a Ru(ii) oxidation state and thus the oxidation step is avoided. By tuning the reaction temperature, ortho allyl and vinyl benzamides were prepared exclusively. Later, ortho allyl and vinylated benzamides were converted into biologically useful six- and five-membered benzolactones in the presence of HCl. PMID:27456467

  14. Toward Efficient Palladium-Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Jensen, Thomas; Fristrup, Peter

    2009-01-01

    Recent breakthroughs have proved that direct palladium (II)-catalyzed allylic C-H alkylation can be achieved. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalyzed allylic alkylation can be lifted. These initial reports hold great promise...

  15. Highly efficient redox isomerization of allylic alcohols at ambient temperature catalyzed by novel ruthenium-cyclopentadienyl complexes--new insight into the mechanism.

    Science.gov (United States)

    Martín-Matute, Belén; Bogár, Krisztián; Edin, Michaela; Kaynak, F Betül; Bäckvall, Jan-E

    2005-10-01

    A range of ruthenium cyclopentadienyl (Cp) complexes have been prepared and used for isomerization of allylic alcohols to the corresponding saturated carbonyl compounds. Complexes bearing CO ligands show higher activity than those with PPh3 ligands. The isomerization rate is highly affected by the substituents on the Cp ring. Tetra(phenyl)methyl-substituted catalysts rapidly isomerize allylic alcohols under very mild reaction conditions (ambient temperature) with short reaction times. Substituted allylic alcohols have been isomerized by employing Ru-Cp complexes. A study of the isomerization catalyzed by [Ru(Ph5Cp)(CO)2H] (14) indicates that the isomerization catalyzed by ruthenium hydrides partly follows a different mechanism than that of ruthenium halides activated by KOtBu. Furthermore, the lack of ketone exchange when the isomerization was performed in the presence of an unsaturated ketone (1 equiv), different from that obtained by dehydrogenation of the starting allylic alcohol, supports a mechanism in which the isomerization takes place within the coordination sphere of the ruthenium catalyst. PMID:16028298

  16. Iridium-catalyzed allylic substitutions with cyclometalated phosphoramidite complexes bearing a dibenzocyclooctatetraene ligand: preparation of (π-allyl)Ir complexes and computational and NMR spectroscopic studies.

    Science.gov (United States)

    Raskatov, Jevgenij A; Jäkel, Mascha; Straub, Bernd F; Rominger, Frank; Helmchen, Günter

    2012-11-01

    (π-Allyl)Ir complexes derived from dibenzocyclooctatetraene and phosphoramidites by cyclometalation are effective catalysts for allylic substitution reactions of linear monosubstituted allylic carbonates. These catalysts provide exceptionally high degrees of regioselectivity and allow the reactions to be run under aerobic conditions. A series of (π-allyl)Ir complexes were prepared and characterized by X-ray crystal structure analyses. An allylic amination with aniline displayed different resting states depending on the presence of a strong base. DFT calculations were carried out on the mechanistic aspects of these reactions. The results suggest that for the (π-allyl)Ir complexes, the formation and reactions with nucleophiles proceed with comparable rates. PMID:23018807

  17. One-pot synthesis of arene-fused 2-acylcyclohexenones from propargylic carboxylates

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    From readily available propargylic carboxylates, two sequential transformations―gold-catalyzed tandem reactions and Sc(OTf)3-catalyzed cyclization―in a one-pot process led to the formation of 2-acylcyclohexenones with an electron-rich arene ring fused at the 4,5-positions.

  18. One-pot synthesis of arene-fused 2-acylcyclohexenones from propargylic carboxylates

    Institute of Scientific and Technical Information of China (English)

    CAO SanSan; ZHANG LiMing

    2009-01-01

    From readily available propargylic carboxylates,two sequential transformations-gold-catalyzed tandem reactions and ScOTf3-catalyzed cyclization-in a one-pot process led to the formation of 2-acylcyclohexenones with an electron-rich arene ring fused at the 4,5-positions.

  19. Radical carbonylations using a continuous microflow system

    Directory of Open Access Journals (Sweden)

    Takahide Fukuyama

    2009-07-01

    Full Text Available Radical-based carbonylation reactions of alkyl halides were conducted in a microflow reactor under pressurized carbon monoxide gas. Good to excellent yields of carbonylated products were obtained via radical formylation, carbonylative cyclization and three-component coupling reactions, using tributyltin hydride or TTMSS as a radical mediator.

  20. Zinc Mediated Tandem Fragmentation-Allylation of Methyl 5-Iodopentofuranosides

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Madsen, Robert

    1999-01-01

    In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols.......In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols....

  1. A Striking Exception to the Chelate Model for Acyclic Diastereocontrol: Efficient Access to a Versatile Propargyl Alcohol for Chemical Synthesis

    OpenAIRE

    Clark, Ronald J.; Gregory B. Dudley; Tlais, Sami F

    2009-01-01

    The four-step, asymmetric synthesis of a chiral propargyl alcohol 1 from (R)-pantolactone is described. A key feature of the synthesis is a diastereoselective acetylide addition to a chiral α-alkoxy-aldehyde 7, in which unusual Felkin selectivity is observed, despite the potential for chelation control. Crystalline propargyl alcohol 1 is valuable for complex molecule synthesis, and is easy to prepare in multi-gram quantities and high diastereomeric purity.

  2. A Striking Exception to the Chelate Model for Acyclic Diastereocontrol: Efficient Access to a Versatile Propargyl Alcohol for Chemical Synthesis

    Directory of Open Access Journals (Sweden)

    Ronald J. Clark

    2009-12-01

    Full Text Available The four-step, asymmetric synthesis of a chiral propargyl alcohol 1 from (R-pantolactone is described. A key feature of the synthesis is a diastereoselective acetylide addition to a chiral α-alkoxy-aldehyde 7, in which unusual Felkin selectivity is observed, despite the potential for chelation control. Crystalline propargyl alcohol 1 is valuable for complex molecule synthesis, and is easy to prepare in multi-gram quantities and high diastereomeric purity.

  3. Rhodium-Catalyzed Acyloxy Migration of Propargylic Esters in Cycloadditions, Inspiration from Recent “Gold Rush”

    OpenAIRE

    Shu, Xing-Zhong; Shu, Dongxu; Schienebeck, Casi M.; TANG, WEIPING

    2012-01-01

    Transition metal-catalyzed acyloxy migration of propargylic esters offers versatile entries to allene and vinyl carbene intermediates for various fascinating subsequent transformations. Most π-acidic metals (e.g. gold and platinum) are capable of facilitating these acyloxy migration events. However, very few of these processes involve redox chemistry, which are well-known for most other transition metals such as rhodium. The coupling of acyloxy migration of propargylic esters with oxidative a...

  4. Biotransformation of sesquiterpenoids having α,β-unsaturated carbonyl groups with cultured plant cells of Marchantia polymorpha

    OpenAIRE

    Hegazy, Mohamed-Elamir F.; Kuwata, Chika; Matsushima, Akihito; Ahmed, Ahmed A.; Hirata, Toshifumi

    2006-01-01

    The biotransformation of sesquiterpenoids having an α,β-unsaturated carbonyl group, such as -santonin (1), lancerodiol p-hydroxybenzoate (2), 8,9-dehydronootkatone (3) and nootkatone (4), with cultured suspension cells of Marchantia polymorpha was investigated. It was found that the C-C double bond of 1 and 2 was hydrogenated to give 1,2-dihydro--santonin (5) and 3,4-dihydrolancerodiol p-hydroxybenzoate (6), respectively, while the allylic position of the C-C double bond of 3 and 4 was hydr...

  5. Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled `Nanozyme

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Courntey J.; Fiedler, Dorothea; Bergman, Robert G.; Raymond, Kenneth N.

    2008-02-27

    The tetrahedral [Ga{sub 4}L{sub 6}]{sup 12-} assembly (L = N,N-bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene) encapsulates a variety of cations, including propargyl enammonium cations capable of undergoing the aza Cope rearrangement. For propargyl enammonium substrates that are encapsulated in the [Ga{sub 4}L{sub 6}]{sup 12-} assembly, rate accelerations of up to 184 are observed when compared to the background reaction. After rearrangement, the product iminium ion is released into solution and hydrolyzed allowing for catalytic turnover. The activation parameters for the catalyzed and uncatalyzed reaction were determined, revealing that a lowered entropy of activation is responsible for the observed rate enhancements. The catalyzed reaction exhibits saturation kinetics; the rate data obey the Michaelis-Menten model of enzyme kinetics, and competitive inhibition using a non-reactive guest has been demonstrated.

  6. Rotational spectra of propargyl alcohol dimer: A dimer bound with three different types of hydrogen bonds

    International Nuclear Information System (INIS)

    Pure rotational spectra of the propargyl alcohol dimer and its three deuterium isotopologues have been observed in the 4 to 13 GHz range using a pulsed-nozzle Fourier transform microwave spectrometer. For the parent dimer, a total of 51 transitions could be observed and fitted within experimental uncertainty. For two mono-substituted and one bi-substituted deuterium isotopologues, a total of 14, 17, and 19 transitions were observed, respectively. The observed rotational constants for the parent dimer [A = 2321.8335(4) MHz, B = 1150.4774(2) MHz, and C = 1124.8898(2) MHz] are close to those of the most stable structure predicted by ab initio calculations. Spectra of the three deuterated isotopologues and Kraitchman analysis positively confirm this structure. Geometrical parameters and “Atoms in Molecules” analysis on the observed structure reveal that the two propargyl alcohol units in the dimer are bound by three different types of hydrogen bonds: O–H⋯O, O–H⋯π, and C–H⋯π. To the best of our knowledge, propargyl alcohol seems to be the smallest molecule forming a homodimer with three different points of contact

  7. Rotational spectra of propargyl alcohol dimer: A dimer bound with three different types of hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Devendra; Arunan, E., E-mail: arunan@ipc.iisc.ernet.in [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)

    2014-10-28

    Pure rotational spectra of the propargyl alcohol dimer and its three deuterium isotopologues have been observed in the 4 to 13 GHz range using a pulsed-nozzle Fourier transform microwave spectrometer. For the parent dimer, a total of 51 transitions could be observed and fitted within experimental uncertainty. For two mono-substituted and one bi-substituted deuterium isotopologues, a total of 14, 17, and 19 transitions were observed, respectively. The observed rotational constants for the parent dimer [A = 2321.8335(4) MHz, B = 1150.4774(2) MHz, and C = 1124.8898(2) MHz] are close to those of the most stable structure predicted by ab initio calculations. Spectra of the three deuterated isotopologues and Kraitchman analysis positively confirm this structure. Geometrical parameters and “Atoms in Molecules” analysis on the observed structure reveal that the two propargyl alcohol units in the dimer are bound by three different types of hydrogen bonds: O–H⋯O, O–H⋯π, and C–H⋯π. To the best of our knowledge, propargyl alcohol seems to be the smallest molecule forming a homodimer with three different points of contact.

  8. Origins of stereoselectivities in chiral phosphoric acid catalyzed allylborations and propargylations of aldehydes.

    Science.gov (United States)

    Wang, Hao; Jain, Pankaj; Antilla, Jon C; Houk, K N

    2013-02-01

    The chiral BINOL-phosphoric acid catalyzed allylboration and propargylation reactions are studied with density functional theory (B3LYP and B3LYP-D3). Two different models were recently proposed for these reactions by Goodman and our group, respectively. In Goodman's model for allylborations, the catalyst interacts with the boronate pseudoaxial oxygen. By contrast, our model for propargylations predicts that the catalyst interacts with the boronate pseudoequatorial oxygen. In both models, the phosphoric acid stabilizes the transition state by forming a strong hydrogen bond with the oxygen of the boronate and is oriented by a formyl hydrogen bond (Goodman model) and by other electrostatic attractions in our model. Both of these models have now been reinvestigated for both allylborations and propargylations. For the most effective catalyst for these reactions, the lowest energy transition state corresponds to Goodman's axial model, while the best transition state leading to the minor enantiomer involves the equatorial model. The high enantioselectivity observed with only the bulkiest catalyst arises from the steric interactions between the substrates and the bulky groups on the catalyst, and the resulting necessity for distortion of the catalyst in the disfavored transition state. PMID:23298338

  9. Kinetics of the Double Carbonylation of Benzylchloride

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is a multi-phase-catalyzed reaction to produce calcium phenylpyruvate by double carbonylation of benzylchloride. Based on the analysis of the reaction mechanism, a kinetic model of the carbonylation reaction was obtained. The model was verified through experiments in which the diffusion effect was neglected with the appropriate operation manner. But it is inevitable that the carbonylation process is controlled by diffusion as the autoclave scaling up.

  10. Scalable and sustainable electrochemical allylic C-H oxidation

    Science.gov (United States)

    Horn, Evan J.; Rosen, Brandon R.; Chen, Yong; Tang, Jiaze; Chen, Ke; Eastgate, Martin D.; Baran, Phil S.

    2016-05-01

    New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as “classics”. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact.

  11. Structurally defined allyl compounds of main group metals: coordination and reactivity.

    Science.gov (United States)

    Lichtenberg, Crispin; Okuda, Jun

    2013-05-10

    Organometallic allyl compounds are important as allylation reagents in organic synthesis, as polymerization catalysts, and as volatile metal precursors in material science. Whereas the allyl chemistry of synthetically relevant transition metals such as palladium and of the lanthanoids is well-established, that of main group metals has been lagging behind. Recent progress on allyl complexes of Groups 1, 2, and 12-16 now provides a more complete picture. This is based on a fundamental understanding of metal-allyl bonding interactions in solution and in the solid state. Furthermore, reactivity trends have been rationalized and new types of allyl-specific reactivity patterns have been uncovered. Key features include 1) the exploitation of the different types of metal-allyl bonding (highly ionic to predominantly covalent), 2) the use of synergistic effects in heterobimetallic compounds, and 3) the adjustment of Lewis acidity by variation of the charge of allyl compounds.

  12. 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.

  13. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  14. Iridium-Catalyzed Selective Isomerization of Primary Allylic Alcohols.

    Science.gov (United States)

    Li, Houhua; Mazet, Clément

    2016-06-21

    This Account presents the development of the iridium-catalyzed isomerization of primary allylic alcohols in our laboratory over the past 8 years. Our initial interest was driven by the long-standing challenge associated with the development of a general catalyst even for the nonasymmetric version of this seemingly simple chemical transformation. The added value of the aldehyde products and the possibility to rapidly generate molecular complexity from readily accessible allylic alcohols upon a redox-economical isomerization reaction were additional sources of motivation. Certainly influenced by the success story of the related isomerization of allylic amines, most catalysts developed for the selective isomerization of allylic alcohols were focused on rhodium as a transition metal of choice. Our approach has been based on the commonly accepted precept that hydrogenation and isomerization are often competing processes, with the latter being usually suppressed in favor of the former. The cationic iridium complexes [(Cy3P)(pyridine)Ir(cod)]X developed by Crabtree (X = PF6) and Pfaltz (X = BArF) are usually considered as the most versatile catalysts for the hydrogenation of allylic alcohols. Using molecular hydrogen to generate controlled amounts of the active form of these complexes but performing the reaction in the absence of molecular hydrogen enabled deviation from the typical hydrogenation manifold and favored exclusively the isomerization of allylic alcohols into aldehydes. Isotopic labeling and crossover experiments revealed the intermolecular nature of the process. Systematic variation of the ligand on the iridium center allowed us to identify the structural features beneficial for catalytic activity. Subsequently, three generations of chiral catalysts have been investigated and enabled us to reach excellent levels of enantioselectivity for a wide range of 3,3-disubstituted aryl/alkyl and alkyl/alkyl primary allylic alcohols leading to β-chiral aldehydes. The

  15. Surface decorated platinum carbonyl clusters

    Science.gov (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore

    2012-06-01

    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  16. Highly Enantioselective Formation of α-Allyl-α-Arylcyclopentanones via Pd-Catalysed Decarboxylative Asymmetric Allylic Alkylation.

    Science.gov (United States)

    Akula, Ramulu; Doran, Robert; Guiry, Patrick J

    2016-07-11

    A highly enantioselective Pd-catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α-aryl-β-keto esters employing the (R,R)-ANDEN-phenyl Trost ligand has been developed. The product (S)-α-allyl-α-arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee). This represents one of the most highly enantioselective formations of an all-carbon quaternary stereogenic center reported to date. This reaction was demonstrated on a 4.0 mmol scale without any deterioration of enantioselectivity and was exploited as the key enantioselective transformation in an asymmetric formal synthesis of the natural product (+)-tanikolide. PMID:27191198

  17. Sulfonium-based Ionic Liquids Incorporating the Allyl Functionality

    Directory of Open Access Journals (Sweden)

    Paul J. Dyson

    2007-04-01

    Full Text Available A series of sulfonium halides bearing allyl groups have been prepared andcharacterized. Anion metathesis with Li[Tf2N] and Ag[N(CN2] resulted in sulfonium-basedionic liquids which exhibit low viscosities at room temperature. The solid state structure ofone of the halide salts was determined by single crystal X-ray diffraction.

  18. Electrochemical Allylic Oxidation of Olefins: Sustainable and Safe.

    Science.gov (United States)

    Waldvogel, Siegfried R; Selt, Maximilian

    2016-10-01

    The power you're supplying: With the application of an optimized electrochemical approach, the allylic oxidation of olefins, which is an important C-H activation process that provides access to enones, becomes a sustainable, versatile, and potent key reaction for organic synthesis.

  19. Propargyl Recombination: Estimation of the High Temperature, Low Pressure Rate Constant from Flame Measurements

    DEFF Research Database (Denmark)

    Rasmussen, Christian Lund; Skjøth-Rasmussen, Martin Skov; Jensen, Anker;

    2005-01-01

    3 at temperatures below 1000 K, while data at high temperature and low pressure only can be obtained from flames. In the present work, an estimate of the rate constant for the reaction at 1400 +/- 50 K and 20 Torr is obtained from analysis of the fuel-rich acetylene flame of Westmoreland, Howard......)/mol-s, with C6H5 + H as the dominating product channel. The estimated uncertainty in this value, a factor of 5, mainly originates from the uncertainty in the measured propargyl radical profile, although other experimental and kinetic uncertainties also contribute. (c) 2004 The Combustion Institute....... Published by Elsevier Inc. All rights reserved....

  20. Trifluoromethylation of Carbonyl Compounds with Sodium Trifluoroacetate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In the presence of copper (Ⅰ) halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.

  1. Rapid Access to Spirocyclized Indolenines via Palladium-Catalyzed Cascade Reactions of Tryptamine Derivatives and Propargyl Carbonate

    OpenAIRE

    Montgomery, Thomas D.; Nibbs, Antoinette E.; Zhu, Ye; Rawal, Viresh H.

    2014-01-01

    We report the intermolecular palladium-catalyzed reaction of tert-butyl propargyl carbonate with tryptamine derivatives or other indole-containing bis-nucleophiles. The reaction proceeds under mild conditions and with low catalyst loadings to afford novel spiroindolenine products in good to high yields.

  2. Branching Out: Rhodium-Catalyzed Allylation with Alkynes and Allenes.

    Science.gov (United States)

    Koschker, Philipp; Breit, Bernhard

    2016-08-16

    We present a new and efficient strategy for the atom-economic transformation of both alkynes and allenes to allylic functionalized structures via a Rh-catalyzed isomerization/addition reaction which has been developed in our working group. Our methodology thus grants access to an important structural class valued in modern organic chemistry for both its versatility for further functionalization and the potential for asymmetric synthesis with the construction of a new stereogenic center. This new methodology, inspired by mechanistic investigations by Werner in the late 1980s and based on preliminary work by Yamamoto and Trost, offers an attractive alternative to other established methods for allylic functionalization such as allylic substitution or allylic oxidation. The main advantage of our methodology consists of the inherent atom economy in comparison to allylic oxidation or substitution, which both produce stoichiometric amounts of waste and, in case of the substitution reaction, require prefunctionalization of the starting material. Starting out with the discovery of a highly branched-selective coupling reaction of carboxylic acids with terminal alkynes using a Rh(I)/DPEphos complex as the catalyst system, over the past 5 years we were able to continuously expand upon this chemistry, introducing various (pro)nucleophiles for the selective C-O, C-S, C-N, and C-C functionalization of both alkynes and the double-bond isomeric allenes by choosing the appropriate rhodium/bidentate phosphine catalyst. Thus, valuable compounds such as branched allylic ethers, sulfones, amines, or γ,δ-unsaturated ketones were successfully synthesized in high yields and with a broad substrate scope. Beyond the branched selectivity inherent to rhodium, many of the presented methodologies display additional degrees of selectivity in regard to regio-, diastereo-, and enantioselective transformations, with one example even proceeding via a dynamic kinetic resolution. Many advances

  3. Stratospheric carbonyl sulfide (OCS) burden

    Science.gov (United States)

    Kloss, Corinna; Walker, Kaley A.; Deshler, Terry; von Hobe, Marc

    2015-04-01

    An estimation of the global stratospheric burden of carbonyl sulfide (OCS) calculated using satellite based measurements from the Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS) will be presented. OCS is the most abundant sulfur containing gas in the atmosphere in the absence of volcanic eruptions. With a long lifetime of 2-6 years it reaches the stratosphere where it is photolyzed and the sulfur oxidized and condensed to aerosols, contributing to the stratospheric aerosol layer. The aerosol layer is the one factor of the middle-atmosphere with a direct impact on the Earth's climate by scattering incoming solar radiation back to space. Therefore it is crucial to understand and estimate the different processes and abundances of the species contributing to the aerosol layer. However, the exact amount of OCS in the stratosphere has not been quantified yet. A study on the OCS mixing ratio distribution based on ACE-FTS data has already been made by Barkley et al. (2008), also giving an estimation for the total atmospheric OCS mass. ACE-FTS is an infrared solar occultation spectrometer providing high- resolution profile observations since 2004. In the scope of this work the focus lies on the stratospheric OCS burden, calculated by integrating the ACE profiles. A global overview on the stratospheric OCS amount in the past and present based on the ACE data as well as a look at regional and seasonal variability will be given. Furthermore, the results of this work will be useful for further studies on OCS fluxes and lifetimes, and in quantifying the contribution of OCS to the global stratospheric sulfur burden. Barkley et al., 2008, Geophys. Res. Lett., 35, L14810.

  4. SYNTHESIS, STRUCTURE AND BIOLOGICAL ACTIVITY OF N(4-ALLYL-3-THIOSEMICARBAZONES AND THEIR COORDINATION COMPOUNDS WITH SOME 3D METALS

    Directory of Open Access Journals (Sweden)

    Vasilii GRAUR

    2016-02-01

    Full Text Available The paper presents a review of different N(4-allyl-3-thiosemicarbazones and their coordination compounds described in literature. N(4-allyl-3-thiosemicarbazide can form corresponding thiosemicarbazones with aliphatic, aromatic and heteroaromatic carbonyl compounds. In the presence of transitional metal ions they can form coordination compounds of different structures. Both coordination compounds and proligands manifest antitumor, antibacterial, antiviral, and antimalarial activities. Copper(II coordination compounds with these ligands manifest better antitumor activity than corresponding proligands. SINTEZA, STRUCTURA ŞI ACTIVITATEA BIOLOGICĂ A N(4-ALIL-3-TIOSEMICARBAZONELOR ŞI A COMPUŞILOR COORDINATIVI AI UNOR METALE 3D CU ACEŞTI LIGANZILucrarea prezintă o revistă a N(4-alil-3-tiosemicarbazonelor şi a compuşilor coordinativi cu aceşti liganzi descrise în literatura de specialitate. N(4-alil-3-tiosemicarbazida formează tiosemicarbazone cu aldehide şi cetone alifatice, aro­matice şi heteroaromatice. În prezenţa ionilor de metale de tranziţie acestea pot forma compuşi coordinativi cu diferite structuri. N(4-alil-3-tiosemicarbazonele şi compuşii coordinativi manifestă activitate antitumorală, antibacterială, antivirală şi antimalarică. Compuşii coordinativi ai cuprului cu aceşti liganzi manifestă activitate antitumorală sporită în comparaţie cu N(4-alil-3-tiosemicarbazonele corespunzătoare. 

  5. ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS

    Science.gov (United States)

    Kennedy, J.

    1959-04-14

    An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

  6. Radiation initiated copolymerization of allyl alcohol with acrylonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Solpan, Dilek; Guven, Olgun [Hacettepe Univ., Ankara (Turkey). Dept. of Chemistry

    1996-07-01

    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by {gamma}-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tudos (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively. (Author).

  7. Radiation initiated copolymerization of allyl alcohol with acrylonitrile

    Science.gov (United States)

    Şolpan, Dilek; Güven, Olgun

    1996-07-01

    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by γ-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tüdös (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively.

  8. Enantioconvergent synthesis by sequential asymmetric Horner-Wadsworth-Emmons and palladium-catalyzed allylic substitution reactions

    DEFF Research Database (Denmark)

    Pedersen, Torben Møller; Hansen, E. Louise; Kane, John;

    2001-01-01

    A new method for enantioconvergent synthesis has been developed. The strategy relies on the combination of an asymmetric Horner-Wadsworth-Emmons (HWE) reaction and a palladium-catalyzed allylic substitution. Different $alpha@-oxygen-substituted, racemic aldehydes were initially transformed by...... asymmetric HWE reactions into mixtures of two major $alpha@,$beta@-unsaturated esters, possessing opposite configurations at their allylic stereocenters as well as opposite alkene geometry. Subsequently, these isomeric mixtures of alkenes could be subjected to palladium-catalyzed allylic substitution...

  9. Gold(I)-Assisted α-Allylation of Enals and Enones with Alcohols.

    Science.gov (United States)

    Mastandrea, Marco Michele; Mellonie, Niall; Giacinto, Pietro; Collado, Alba; Nolan, Steven P; Miscione, Gian Pietro; Bottoni, Andrea; Bandini, Marco

    2015-12-01

    The intermolecular α-allylation of enals and enones occurs by the condensation of variously substituted allenamides with allylic alcohols. Cooperative catalysis by [Au(ItBu)NTf2] and AgNTf2 enables the synthesis of a range of densely functionalized α-allylated enals, enones, and acyl silanes in good yield under mild reaction conditions. DFT calculations support the role of an α-gold(I) enal/enone as the active nucleophilic species.

  10. Self-healing corrosion protection by nanostructure sol-gel impregnated with propargyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, S.M.A. [Department of Chemistry, Shahid Bahonar University of Kerman, 22 Bahman, Kerman-76175 (Iran, Islamic Republic of); Jafari, A.H., E-mail: Jafari@mail.uk.ac.i [Department of Materials Science and Engineering, Shahid Bahonar University of Kerman, Jomhori Bulvar, Kerman-76188 (Iran, Islamic Republic of); Jamalizadeh, E. [Department of Chemistry, Shahid Bahonar University of Kerman, 22 Bahman, Kerman-76175 (Iran, Islamic Republic of)

    2009-12-01

    Zirconia based nanostructured hybrid sol-gel coating, impregnated with propargyl alcohol (PA) to hinder corrosion of mild steel was studied. Zirconia nano-particles (TPOZ) contained sol-gel was synthesized using 3-glycidoxypropyltrimethoxysilane (GPTMS) as precursor and subsequently optimized for internal cohesion as well as adhesion to the mild steel substrate to assess the consequent effect on suppression of corrosion damage in 0.5 M NaCl solution. Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscopy (SEM) results demonstrated the effect of coating integrity on impeding corrosion. Experiments on mild steel specimens coated with hybrid sol-gel films following mechanical polishing render superior corrosion resistance to mild steel in contrast to those undergoing electrochemical polishing with marked lower surface roughness. Results also proved of beneficial effect of low and exact concentration of PA on sol-gel coat's barrier properties evident from diminished corrosion current and other electrochemical indicators.

  11. Magnetic silica supported palladium catalyst: synthesis of allyl aryl ethers in water

    Science.gov (United States)

    A simple and benign procedure for the synthesis of aryl allyl ethers has been developed using phenols, allyl acetates and magnetically recyclable silica supported palladium catalyst in water; performance of reaction in air and easy separation of the catalyst using an external mag...

  12. Palladium(0)-Catalyzed Intermolecular Allylic Dearomatization of Indoles by a Formal [4+2] Cycloaddition Reaction.

    Science.gov (United States)

    Gao, Run-Duo; Xu, Qing-Long; Zhang, Bo; Gu, Yiting; Dai, Li-Xin; You, Shu-Li

    2016-08-01

    Bridged indoline derivatives were synthesized by an intermolecular Pd-catalyzed allylic dearomatization reaction of substituted indoles. The reaction between indoles and allyl carbonates bearing a nucleophilic alcohol side-chain proceeds in a cascade fashion, providing bridged indolines in excellent enantioselectivity. PMID:27321285

  13. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis.

    Science.gov (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M

    2015-01-11

    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions.

  14. Memory effects in palladium-catalyzed allylic Alkylations of 2-cyclohexen-1-yl acetate

    DEFF Research Database (Denmark)

    Svensen, Nina; Fristrup, Peter; Tanner, David Ackland;

    2007-01-01

    The objective of this work was to characterize the enantiospecificity of the allylic alkylation of enantioenriched 2-cyclohexen-1-yl acetate with the enolate ion of dimethyl malonate catalyzed by unsymmetrical palladium catalysts. The precatalysts employed were (eta(3)-allyl)PdLCl, where L...

  15. Pd-catalyzed cascade allylic alkylation and dearomatization reactions of indoles with vinyloxirane.

    Science.gov (United States)

    Gao, Run-Duo; Xu, Qing-Long; Dai, Li-Xin; You, Shu-Li

    2016-09-14

    We have developed Pd-catalyzed intermolecular Friedel-Crafts-type allylic alkylation and allylic dearomatization reactions of substituted indoles bearing a nucleophilic group with vinyloxirane, providing an efficient method to synthesize structurally diverse tetrahydrocarboline and spiroindolenine derivatives under mild conditions. PMID:27511802

  16. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis.

    Science.gov (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M

    2015-01-11

    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions. PMID:25410944

  17. A route to hydroxylfluorenes: TsOH-mediated condensation reactions of 1,3-diketones with propargylic alcohols

    KAUST Repository

    Yao, Liangfeng

    2012-01-01

    An efficient method of preparing hydroxylfluorenes by TsOH-mediated tandem alkylation/rearrangements of propargylic alcohols with 1,3-diketones is described. These reactions are accomplished in moderate to good yields under mild conditions to offer a straightforward and convenient one step synthetic route to hydroxylfluorene derivatives through a plausible mechanism involving a sequence of dehydration, addition, rearrangement and aromatization. This journal is © The Royal Society of Chemistry 2012.

  18. Pressure Effects on Product Channels of the Allyl Radical Reactions; C3H5+C3H5 and C3H5+CH3

    Science.gov (United States)

    Halpern, J. B.; N'Doumi, M.; Fahr, A.

    2011-12-01

    Relatively large hydrocarbon molecules (C4, C6 and larger) have been detected in several planetary environments. The mechanism for the formation of such large molecular species and detailed mechanism for their potential destruction are not well understood and are of considerable current interest. Previously we have studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modeling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. Pressure-dependent product yields have been determined experimentally for the self- and cross-radical reactions performed at 298 K and at pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final reaction products were quantitatively determined using a gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the experiments and provided valuable information on the complex reaction mechanisms. Theses studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report recent results for the allyl radical reactions H2CCCH3+ H2CCCH3 and H2CCCH3+CH3. For the allyl radical self-reaction, at high pressures the "head -to-head", combination channel forming 1,5-hexadiene is dominant with a combination/disproportionation = 1,5-hexadiene/propyne ratio of about 24 at 500 Torr (67 kPa, T=298K). At low pressures the ratio is substantially reduced to about 1.2 (at 0.3 kPa) and other major products are observed including allene, propene, 1-butene and propyne.

  19. Construction of an Asymmetric Quaternary Carbon Center via Allylation of Hydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Bum; Satyender, Apuri; Jang, Doo Ok [Yonsei Univ., Wonju (Korea, Republic of)

    2013-11-15

    Asymmetric indium-mediated allylation of imine derivatives bearing a chiral auxiliary is a reliable strategy for the synthesis of chiral homoallylic amines. Various techniques for indium-mediated stereoselective allylation of imines bearing a chiral auxiliary have been reported. In 1997 Loh and co-workers reported indium-mediated allylation with imines derived from L-valine methyl ester. Since then, many forms of indium-mediated allylation bearing a chiral auxiliary have been reported, including imines derived from (S)-valinol, (R)-phenylglycinol, uracil, (R)-phenylglycinol methyl ester, N-tert-butanesufinamide, and (1R,2S)-1-amino-2-indanol. However, the synthesis of chiral auxiliaries often involves a laborious multi-step synthesis with expensive reagents. Therefore, the development of readily accessible chiral auxiliaries for asymmetric indium-mediated all-ylation is in high demand.

  20. Millimeter wave spectra of carbonyl cyanide ⋆

    Science.gov (United States)

    Bteich, S.B.; Tercero, B.; Cernicharo, J.; Motiyenko, R.A.; Margulès, L.; Guillemin, J.-C.

    2016-01-01

    Context More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. Aims The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. Methods The rotational spectrum of carbonyl cyanide was measured in the frequency range 152 - 308 GHz and analyzed using Watson’s A- and S-reduction Hamiltonians. Results The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources. PMID:27738349

  1. 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.

  2. Enantioselective functionalization of allylic C-H bonds following a strategy of functionalization and diversification.

    Science.gov (United States)

    Sharma, Ankit; Hartwig, John F

    2013-11-27

    We report the enantioselective functionalization of allylic C-H bonds in terminal alkenes by a strategy involving the installation of a temporary functional group at the terminal carbon atom by C-H bond functionalization, followed by the catalytic diversification of this intermediate with a broad scope of reagents. The method consists of a one-pot sequence of palladium-catalyzed allylic C-H bond oxidation under neutral conditions to form linear allyl benzoates, followed by iridium-catalyzed allylic substitution. This overall transformation forms a variety of chiral products containing a new C-N, C-O, C-S, or C-C bond at the allylic position in good yield with a high branched-to-linear selectivity and excellent enantioselectivity (ee ≤97%). The broad scope of the overall process results from separating the oxidation and functionalization steps; by doing so, the scope of nucleophile encompasses those sensitive to direct oxidative functionalization. The high enantioselectivity of the overall process is achieved by developing an allylic oxidation that occurs without acid to form the linear isomer with high selectivity. These allylic functionalization processes are amenable to an iterative sequence leading to (1,n)-functionalized products with catalyst-controlled diastereo- and enantioselectivity. The utility of the method in the synthesis of biologically active molecules has been demonstrated.

  3. Theoretical Study on the Mechanism of the Gas-phase Reaction of Sc+ with Propargyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-Ping; CHEN Hong-Yan; CHENG Wei-Xian; FENG Yu; YANG Li-Jun

    2008-01-01

    In order to elucidate the reaction mechanisms of reaction Sc+ with propargyl alcohol(PPA),the triplet potential energy surface for the reactions has been theoretically investigated using a DFT method.The geometries for the reactants,intermediates,transition states and products were completely optimized at B3LYP/DZVP level.The single point energy of each stationary point was calculated at MP4/(6-311+G** for C,H,O and Lanl2dz for Sc+)level.All the transition states were verified by the vibrational analysis and the internal reaction coordinate(IRC)calculations.The present results show that the reaction takes an insertion-elimination mechanism both along the O-H and C-O bond activation branches,but the C-O bond activation is much more favorable in energy than the O-H bond activation.All theoretical results not only support the existing conclusions inferred from early experiment,but also complement the pathway and mechanism for this reaction.

  4. Isomerization of propargyl cation to cyclopropenyl cation: Mechanistic elucidations and effects of lone pair donors

    Indian Academy of Sciences (India)

    Zodinpuia Pachuau; Kiew S Kharnaior; R H Duncan Lyngdoh

    2013-03-01

    This ab initio study examines two pathways (one concerted and the other two-step) for isomerization of the linear propargyl cation to the aromatic cyclopropenyl cation, also probing the phenomenon of solvation of this reaction by simple lone pair donors (NH3, H2O, H2S and HF) which bind to the substrate at two sites. Fully optimized geometries at the B3LYP/6-31G(d) level were used, along with single point QCISD(T)/6-311+G(d,p) and accurate G3 level calculations upon the DFT optimized geometries. For the unsolvated reaction, the two-step second pathway is energetically favoured over the one-step first pathway. Lone pair donor affinity for the various C3H$^{+}_{3}$ species follows the uniform order NH3 > H2S>H2O>HF. The activation barriers for the solvated isomerizations decrease in the order HF>H2O>H2S>NH3 for both pathways. The number of lone pairs on the donor heteroatom as well as the heteroatom electronegativity are factors related to both these trends. Compared to the unsolvated cases, the solvated reactions have transition states which are usually ‘later’ in position along the reaction coordinate, validating the Hammond postulate.

  5. Photodissociation of the Propargyl (C3D3) Radicals at 248 nm and 193 nm

    Energy Technology Data Exchange (ETDEWEB)

    Neumark., D.M.; Crider, P.E.; Castiglioni, L.; Kautzman, K.K.

    2009-01-21

    The photodissociation of perdeuterated propargyl (D{sub 2}CCCD) and propynyl (D{sub 3}CCC) radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 nm and 450 nm (below and above the electron affinity of propynyl). The radicals were then photodissociated by 248 nm or 193 nm light. The recoiling photofragments were detected in coincidence with a time- and position-sensitive detector. Three channels were observed: D{sub 2} loss, CD + C{sub 2}D{sub 2}, and CD{sub 3} + C{sub 2}. Obervation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D{sub 2} loss peaked at nonzero translational energy, consistent with ground state dissociation over small (< 1 eV) exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.

  6. Conformations of propargyl alcohol and its interaction with acetylene: A matrix isolation infrared and DFT computations

    Science.gov (United States)

    Sundararajan, K.; Gopi, R.; Ramanathan, N.

    2016-10-01

    Conformations of propargyl alcohol (PA) were studied using matrix isolation infrared spectroscopy. DFT computations using 6-311++G(d,p) basis set on the PA molecule identified two minima; gauche (g-PA) and trans (t-PA). Comparison of infrared spectra of PA trapped in Ar, N2 and Xe matrices with computations showed the evidence of the ground state g-PA conformer. Four minima were optimized on the potential energy surface for the hydrogen-bonded interaction of g-PA and acetylene (C2H2), corresponding to complex A (Csbnd H⋯O), complex B (Osbnd H⋯π) and complex C and D (Csbnd H⋯π). The structure, energies and the vibrational wavenumbers were computed for these complexes at B3LYP/6-311++G (d,p) level of theory. The infrared spectra of the hydrogen-bonded complexes between C2H2 and g-PA were studied in Ar matrix. The infrared spectra recorded under matrix isolation conditions revealed the formation of two types of complexes A (Csbnd H⋯O) and B (Osbnd H⋯π). Formation of these complexes was evidenced from the shifts in the vibrational wavenumber of the modes involving the C2H2 and PA submolecules.

  7. Carbonyl compounds generated from electronic cigarettes.

    Science.gov (United States)

    Bekki, Kanae; Uchiyama, Shigehisa; Ohta, Kazushi; Inaba, Yohei; Nakagome, Hideki; Kunugita, Naoki

    2014-10-28

    Electronic cigarettes (e-cigarettes) are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols) when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

  8. Carbonyl Compounds Generated from Electronic Cigarettes

    Directory of Open Access Journals (Sweden)

    Kanae Bekki

    2014-10-01

    Full Text Available Electronic cigarettes (e-cigarettes are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

  9. Magnetorheological characterisation of carbonyl iron based suspension

    Directory of Open Access Journals (Sweden)

    M. Kciuk

    2009-04-01

    Full Text Available Purpose: The main aim of this article was to present the investigation results of magnetorheological fluids (MR composed of carbonyl iron (CI particles and analyse their flow behaviour in terms of the internal structure formation by a control of applied external magnetic field. The morphology, magnetic properties, sedimentation stability, and magnetorheological properties of the examined MR fluids were studied.Design/methodology/approach: Model MR fluid was prepared using silicone oil OKS 1050 mixed with carbonyl iron powder CI. Furthermore, to reduce sedimentation Aerosil 200 was added as stabilizers. In the purpose to determine the properties of the analyzed fluids the sedimentation and dynamic viscosity were investigated.Findings: Dynamic viscosity of investigated magnetorheological fluids rapidly and reversibly change in response to the applied external magnetic field. Moreover added particles of fumed silica inhibited sedimentation of carbonyl iron particles.Research limitations/implications: MR fluids with excellent properties can be applied in various fields of civil engineering, safety engineering, transportation and life science. They offer an outstanding capability of active control of mechanical properties. But there are no systematic published studies of factors affecting the durability of MR fluids and devices. There is very little information on the effects of exposing different MR fluids to temperature, for this reasons further efforts are needed in order to obtain even better results.Originality/value: The investigation results are reliable and could be very useful both for designers and the practitioners of many branches of industry.

  10. A Facile and Mild Synthesis of Trisubstituted Allylic Sulfones from Morita-Baylis-Hillman Carbonates

    Directory of Open Access Journals (Sweden)

    Lin Jiang

    2015-05-01

    Full Text Available An efficient and catalyst-free synthesis of trisubstituted allylic sulfones through an allylic sulfonylation reaction of Morita-Baylis-Hillman (MBH carbonates with sodium sulfinates has been developed. Under the optimized reaction conditions, a series of trisubstituted allylic sulfones were rapidly prepared in good to excellent yields (71%–99% with good to high selectivity (Z/E from 79:21 to >99:1. Compared with known synthetic methods, the current protocol features mild reaction temperature, high efficiency and easily available reagents.

  11. Millimeter wave spectra of carbonyl cyanide

    Science.gov (United States)

    Bteich, S. B.; Tercero, B.; Cernicharo, J.; Motiyenko, R. A.; Margulès, L.; Guillemin, J.-C.

    2016-07-01

    Context. More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. Aims: The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. Methods: The rotational spectrum of carbonyl cyanide was measured in the frequency range 152-308 GHz and analyzed using Watson's A- and S-reduction Hamiltonians. Results: The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan) with NRC (Canada), NSC, and ASIAA (Taiwan), and KASI (Republic of

  12. Inhibition of 3003 aluminum alloy corrosion by propargyl alcohol and tartrate ion and their synergistic effects in 0.5% NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Yazdzad, A.R. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Shahrabi, T. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)], E-mail: tshahrabi34@modares.ac.ir; Hosseini, M.G. [Department of Physical Chemistry, Faculty of Chemistry, Tabriz University, Tabriz (Iran, Islamic Republic of)

    2008-06-15

    The inhibition behaviours of propargyl alcohol (2-propyn-1-ol) and potassium sodium tartrate and their synergistic effects on corrosion of 3003 aluminum alloy in 0.5% NaCl solution have been studied using electrochemical impedance spectroscopy (EIS) and Tafel polarization methods. It was concluded that the inhibition efficiencies increased with increase in the concentrations of the inhibitors. For propargyl alcohol and tartrate ion the optimum in the inhibition efficiencies using EIS method was observed for inhibitors concentrations close to 10{sup -3} M. Both the inhibitors obeyed the Langmuir isotherm and the thermodynamic calculations revealed that the adsorption of inhibitors was of physical nature. The electrochemical results illustrated that tartrate ion and propargyl alcohol have significant synergistic effects on corrosion inhibition of 3003 aluminum alloy. The optimum ratio of concentration for tartrate to alcohol was 5:2.

  13. Carbonyl Emissions from Gasoline and Diesel Motor Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Jakober, Chris A.; Robert, Michael A.; Riddle, Sarah G.; Destaillats, Hugo; Charles, M. Judith; Green, Peter G.; Kleeman, Michael J.

    2007-12-01

    Carbonyls from gasoline powered light-duty vehicles (LDVs) and heavy-duty diesel powered vehicles (HDDVs) operated on chassis dynamometers were measured using an annular denuder-quartz filter-polyurethane foam sampler with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization and chromatography-mass spectrometry analyses. Two internal standards were utilized based on carbonyl recovery, 4-fluorobenzaldehyde forcarbonyls and 6-fluoro-4-chromanone for>_C8 compounds. Gas- and particle-phase emissions for 39 aliphatic and 20 aromatic carbonyls ranged from 0.1 ? 2000 ?g/L fuel for LDVs and 1.8 - 27000 mu g/L fuel for HDDVs. Gas-phase species accounted for 81-95percent of the total carbonyls from LDVs and 86-88percent from HDDVs. Particulate carbonyls emitted from a HDDV under realistic driving conditions were similar to concentrations measured in a diesel particulate matter (PM) standard reference material. Carbonyls accounted for 19percent of particulate organic carbon (POC) emissions from low-emission LDVs and 37percent of POC emissions from three-way catalyst equipped LDVs. This identifies carbonyls as one of the largest classes of compounds in LDV PM emissions. The carbonyl fraction of HDDV POC was lower, 3.3-3.9percent depending upon operational conditions. Partitioning analysis indicates the carbonyls had not achieved equilibrium between the gas- and particle-phase under the dilution factors of 126-584 used in the current study.

  14. Intramolecular hydroarylation of aryl propargyl ethers catalyzed by indium: the mechanism of the reaction and identifying the catalytic species.

    Science.gov (United States)

    Menkir, Mengistu Gemech; Lee, Shyi-Long

    2016-07-01

    The mechanism and regioselectivity of the intramolecular hydroarylation of phenyl propargyl ether catalyzed by indium in gas and solvent phases were investigated by means of the density functional theory method. The computed results revealed that the reaction proceeds through initial π-coordination of the propargyl moiety to the catalyst, which triggers the nucleophilic attack of the phenyl ring via an exo- or endo-dig pathway in a Friedel-Crafts type mechanism. Calculation results obtained employing InI2(+) as the possible catalyst show similar activation energies for the 5-exo-dig and 6-endo-dig pathways. In contrast, the neural catalyst InI3 shows a kinetic preference for 6-endo-dig versus 5-exo-dig cyclizations leading to the experimentally observed product, 2H-chromene. The calculation results suggest that InI3 could be the real catalytic species for this reaction as it shows regioselectivity in agreement with the experimental observation. Furthermore, the 6-endo-dig cyclization through deprotonation/protonation steps is kinetically more favored than the stepwise two consecutive [1,2]-H shift steps. The rate determining step of the whole catalytic cycle is the deprotonation step with an energy barrier of 18.9 kcal mol(-1) in toluene solvent. The effects of substituents on both the phenyl ring and the propargyl moiety on the selectivity and elementary steps of the hydroarylation process were investigated. A methoxy group, particularly at the meta-position, on the phenyl ring largely decreases the energy barrier of the first step for the 6-endo path, though it shows little effect on the activation energies of the second and third steps. Our calculation results are in good agreement with the experimental results. PMID:27298068

  15. Studies on the Synthesis of Morphinan Alkaloid: Preparation of the Key Allylic Silyl Ether Precursor

    Institute of Scientific and Technical Information of China (English)

    Zhen Lei SONG; Yong Qiang TU; Shuan Hu GAO; Yi Jun JIANG; Shu Yu ZHANG

    2005-01-01

    A convergent strategy to the key allylic silyl ether precursor 4 in our synthetic efforts toward morphinan alkaloid is presented. The vital step is the selective 1,2-addition of the organocerium agent of 6 to ketene 5.

  16. Facile synthesis of allyl resinate monomer in an aqueous solution under microwave irradiation

    Indian Academy of Sciences (India)

    Yanju Lu; Mixia Wang; Zhendong Zhao; Yuxiang Chen; Shichao Xu; Jing Wang; Liangwu Bi

    2015-07-01

    We have developed a facile method for production of allyl resinate monomer (allyl rosin ester) via a phase transfer reaction under microwave irradiation. The synthesis of allyl resinate was conducted using allyl chloride and sodium resinate as starting materials in aqueous solution at 50°C for 30 min with a yield of 94.7%, which is 20% higher than conventional heating method. The products precipitated spontaneously from the aqueous phase after reaction, which significantly facilitated the subsequent separation of monomer products. The synthesized monomer product appeared as a viscous liquid, with a viscosity of 460 mPa·s at 25°C and a density of 1.0469 g/cm3. The physical and chemical properties suggested that the synthesized monomer has great potential for free radical polymerization.

  17. Total Synthesis of Clavosolide A via Tandem Allylic Oxidation/Oxa-Conjugate Addition Reaction

    Science.gov (United States)

    Baker, Joseph B.; Kim, Hyoungsu; Hong, Jiyong

    2015-01-01

    The tandem allylic oxidation/oxa-conjugate addition reaction promoted by the gem-disubstituent effect in conjunction with the NHC-mediated oxidative esterification was explored for the facile synthesis of clavosolide A. PMID:26236051

  18. Silver(I)-Catalyzed Synthesis of β-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process.

    Science.gov (United States)

    Song, Qing-Wen; Zhou, Zhi-Hua; Yin, Hong; He, Liang-Nian

    2015-12-01

    The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding β-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

  19. A Novel Thin Film Resistive Humidity Sensor Based on Soluble Conjugated Polymer: (propionic acid)-co-(propargyl alcohol)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)2 (CoCC(CH3)2OH)2 (PPB). Thin film resistive humidity sensor based on the copolymer doped with HClO-4 was prepared. The impedance of the sensor changed from 103~107 W in 95%~30%RH, and the response of that is very quick (<6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.

  20. Propargyl Vinyl Ethers and Tertiary Skipped Diynes: Two Pluripotent Molecular Platforms for Diversity-Oriented Synthesis.

    Science.gov (United States)

    Tejedor, David; López-Tosco, Sara; Méndez-Abt, Gabriela; Cotos, Leandro; García-Tellado, Fernando

    2016-04-19

    During the last years, we have been involved in the development of a diversity-oriented synthetic strategy aimed at transforming simple, linear, and densely functionalized molecular platforms into collections of topologically diverse scaffolds incorporating biologically relevant structural motifs such as N- and O- heterocycles, multifunctionalized aromatic rings, fused macrocycles, etc. The strategy merges the concepts of pluripotency (the property of an array of chemical functionalities to express different chemical outcomes under different chemical environments) and domino chemistry (chemistry based on processes involving two or more bond-forming transformations that take place while the initial reaction conditions are maintained, with the subsequent reaction resulting as a consequence of the functionality installed in the previous one) to transform common multifunctional substrates into complex and diverse molecular frameworks. This design concept constitutes the ethos of the so-called branching cascade strategy, a branch of diversity-oriented synthesis focused on scaffold diversity generation. Two pluripotent molecular platforms have been extensively studied under this merging (branching) paradigm: C4-O-C3 propargyl vinyl ethers (PVEs) and C7 tertiary skipped diynes (TSDs). These are conveniently constructed from simple and commercially available raw materials (alkyl propiolates, ketones, aldehydes, acid chlorides) through multicomponent manifolds (ABB' three-component reaction for PVEs; A2BB' four-component reaction for TSDs) or a simple two-step procedure (for PVEs). Their modular origin facilitates their structural/functional diversification without increasing the number of synthetic steps for their assembly. These two pluripotent molecular platforms accommodate a well-defined and dense array of through-bond/through-space interrelated functionalities on their structures, which defines their primary reactivity principles and establishes the reactivity profile

  1. Propargyl Vinyl Ethers and Tertiary Skipped Diynes: Two Pluripotent Molecular Platforms for Diversity-Oriented Synthesis.

    Science.gov (United States)

    Tejedor, David; López-Tosco, Sara; Méndez-Abt, Gabriela; Cotos, Leandro; García-Tellado, Fernando

    2016-04-19

    During the last years, we have been involved in the development of a diversity-oriented synthetic strategy aimed at transforming simple, linear, and densely functionalized molecular platforms into collections of topologically diverse scaffolds incorporating biologically relevant structural motifs such as N- and O- heterocycles, multifunctionalized aromatic rings, fused macrocycles, etc. The strategy merges the concepts of pluripotency (the property of an array of chemical functionalities to express different chemical outcomes under different chemical environments) and domino chemistry (chemistry based on processes involving two or more bond-forming transformations that take place while the initial reaction conditions are maintained, with the subsequent reaction resulting as a consequence of the functionality installed in the previous one) to transform common multifunctional substrates into complex and diverse molecular frameworks. This design concept constitutes the ethos of the so-called branching cascade strategy, a branch of diversity-oriented synthesis focused on scaffold diversity generation. Two pluripotent molecular platforms have been extensively studied under this merging (branching) paradigm: C4-O-C3 propargyl vinyl ethers (PVEs) and C7 tertiary skipped diynes (TSDs). These are conveniently constructed from simple and commercially available raw materials (alkyl propiolates, ketones, aldehydes, acid chlorides) through multicomponent manifolds (ABB' three-component reaction for PVEs; A2BB' four-component reaction for TSDs) or a simple two-step procedure (for PVEs). Their modular origin facilitates their structural/functional diversification without increasing the number of synthetic steps for their assembly. These two pluripotent molecular platforms accommodate a well-defined and dense array of through-bond/through-space interrelated functionalities on their structures, which defines their primary reactivity principles and establishes the reactivity profile

  2. Pattern of occurrence and occupancy of carbonylation sites in proteins

    DEFF Research Database (Denmark)

    Rao, R Shyama Prasad; Møller, Ian Max

    2011-01-01

    Proteins are targets for modification by reactive oxygen species, and carbonylation is an important irreversible modification that increases during oxidative stress. While information on protein carbonylation is accumulating, its pattern is not yet understood. We have made a meta-analysis of the ......Proteins are targets for modification by reactive oxygen species, and carbonylation is an important irreversible modification that increases during oxidative stress. While information on protein carbonylation is accumulating, its pattern is not yet understood. We have made a meta...... sites. Comparison of metal-catalyzed oxidation of two closely related proteins indicates that this type of carbonylation might not be very specific in proteins. Interestingly, carbonylated sites show a very strong tendency to cluster together in the protein primary sequence hinting at some sort...

  3. Effects of S-propargyl-cysteine (SPRC in caerulein-induced acute pancreatitis in mice.

    Directory of Open Access Journals (Sweden)

    Jenab N Sidhapuriwala

    Full Text Available Hydrogen sulfide (H(2S, a novel gaseous messenger, is synthesized endogenously from L-cysteine by two pyridoxal-5'-phosphate-dependent enzymes, cystathionine β-synthase (CBS and cystathionine γ-lyase (CSE. S-propargyl-cysteine (SPRC is a slow H(2S releasing drug that provides cysteine, a substrate of CSE. The present study was aimed to investigate the effects of SPRC in an in vivo model of acute pancreatitis (AP in mice. AP was induced in mice by hourly caerulein injections (50 µg/kg for 10 hours. Mice were treated with SPRC (10 mg/kg or vehicle (distilled water. SPRC was administered either 12 h before or 3 h before the induction of pancreatitis. Mice were sacrificed 1 h after the last caerulein injection. Blood, pancreas and lung tissues were collected and processed to measure the plasma amylase, plasma H(2S, myeloperoxidase (MPO activities and cytokine levels in pancreas and lung. The results revealed that significant reduction of inflammation, both in pancreas and lung was associated with SPRC given 3 h prior to the induction of AP. Furthermore, the beneficial effects of SPRC were associated with reduction of pancreatic and pulmonary pro-inflammatory cytokines and increase of anti-inflammatory cytokine. SPRC administered 12 h before AP induction did not cause significant improvement in pancreatic and lung inflammation. Plasma H(2S concentration showed significant difference in H(2S levels between control, vehicle and SPRC (administered 3 h before AP treatment groups. In conclusion, these data provide evidence for protective effects of SPRC in AP possibly by virtue of its slow release of endogenous H(2S.

  4. PAH growth initiated by propargyl addition: Mechanism development and computational kinetics

    KAUST Repository

    Raj, Abhijeet Dhayal

    2014-04-24

    Polycyclic aromatic hydrocarbon (PAH) growth is known to be the principal pathway to soot formation during fuel combustion, as such, a physical understanding of the PAH growth mechanism is needed to effectively assess, predict, and control soot formation in flames. Although the hydrogen abstraction C2H2 addition (HACA) mechanism is believed to be the main contributor to PAH growth, it has been shown to under-predict some of the experimental data on PAHs and soot concentrations in flames. This article presents a submechanism of PAH growth that is initiated by propargyl (C 3H3) addition onto naphthalene (A2) and the naphthyl radical. C3H3 has been chosen since it is known to be a precursor of benzene in combustion and has appreciable concentrations in flames. This mechanism has been developed up to the formation of pyrene (A4), and the temperature-dependent kinetics of each elementary reaction has been determined using density functional theory (DFT) computations at the B3LYP/6-311++G(d,p) level of theory and transition state theory (TST). H-abstraction, H-addition, H-migration, β-scission, and intramolecular addition reactions have been taken into account. The energy barriers of the two main pathways (H-abstraction and H-addition) were found to be relatively small if not negative, whereas the energy barriers of the other pathways were in the range of (6-89 kcal·mol-1). The rates reported in this study may be extrapolated to larger PAH molecules that have a zigzag site similar to that in naphthalene, and the mechanism presented herein may be used as a complement to the HACA mechanism to improve prediction of PAH and soot formation. © 2014 American Chemical Society.

  5. Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

    OpenAIRE

    Antonio Monopoli; Pietro Cotugno; Zambonin, Carlo G.; Francesco Ciminale; Angelo Nacci

    2015-01-01

    The Pd–benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand...

  6. Selective epoxidation of allylic alcohols with a titania-silica aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, M.; Mallat, T.; Baiker, A. [Lab. of Technical Chemistry, Swiss Federal Inst. of Technology, ETH-Zentrum, Zuerich (Switzerland)

    1998-12-31

    An amorphous mesoporous titania-silica aerogel (20 wt%TiO{sub 2} - 80 wt% SiO{sub 2}) and tert.-butylhydroperoxide (TBHP) have been used for the epoxidation of various allylic alcohols. Allylic alcohols possessing an internal double bond were more reactive than those with a terminal C=C bond. Epoxide selectivities could be improved by addition of (basic) zeolite 4 A and NaHCO{sub 3} to the reaction mixture. (orig.)

  7. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  8. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2013-01-01

    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... satisfactorily oxidation of OCS over a wide range of stoichiometric air–fuel ratios (0.5 ≤λ≤7.3), temperatures (450–1700 K), and pressures (0.02–3.0 atm) under dry conditions. The governing reaction mechanisms are outlined based on calculations with the kinetic model. The oxidation rate of OCS is controlled...

  9. Clinical Features of Schizophrenia With Enhanced Carbonyl Stress

    OpenAIRE

    Miyashita, Mitsuhiro; Arai, Makoto; Kobori, Akiko; Ichikawa, Tomoe; Toriumi, Kazuya; Niizato, Kazuhiro; Oshima, Kenichi; Okazaki, Yuji; Yoshikawa, Takeo; Amano, Naoji; Miyata, Toshio; Itokawa, Masanari

    2013-01-01

    Accumulating evidence suggests that advanced glycation end products, generated as a consequence of facilitated carbonyl stress, are implicated in the development of a variety of diseases. These diseases include neurodegenerative illnesses, such as Alzheimer disease. Pyridoxamine is one of the 3 forms of vitamin B6, and it acts by combating carbonyl stress and inhibiting the formation of AGEs. Depletion of pyridoxamine due to enhanced carbonyl stress eventually leads to a decrease in the other...

  10. Pollution survey of carbonyl compounds in train air

    Institute of Scientific and Technical Information of China (English)

    LU Hao; ZHU Lizhong

    2007-01-01

    The train iS an important vehicle in China,but its air quality has important impacts on passengers' health.In this work,pollution from carbonyl compounds was measured in the air of six trains.The obiectives of this work were to investigate carbonyl compound levels in selected air from trains,identify their emission sources,and assess the intake of carbonyl compounds for passengers.The methods for sampling and analyzing 10 carbonyl compounds such as formaldehyde,acetaldehyde,acrolein,acetone,propionalde hyde,crotonaldehyde,butyraldehyde,benzaldehyde,cyclo hexanone,and valeraldehyde in indoor air were proposed with the sampling efficiency,recovery,and detection limit being 92%-100%,91%-104%,and 0.26-0.82 ng/m3,respec tively.It was indicated that the total concentrations of carbonyl compounds were 0.159-0.2828 mg/m3 with the average concentration of 0.2330 mg/m3.The average concen trations of formaldehyde.acetaldehyde and acetone were 0.0922,0.0499,and 0.0580 mg/m3,accounting for 42.6%,21.4%.and 24.9% of the total concentrations of carbonyl compounds,respectively.The carbonyl compounds probably came from woodwork and cigarette smoking.The intake of carbonyl compounds for the passengers was approximately 0.043-0.076 mg/h.The carbonyl compounds in train air could be harmful to human health.

  11. Palladium-Catalyzed Dearomative Allylic Alkylation of Indoles with Alkynes To Synthesize Indolenines with C3-Quarternary Centers.

    Science.gov (United States)

    Gao, Shang; Wu, Zijun; Fang, Xinxin; Lin, Aijun; Yao, Hequan

    2016-08-01

    A palladium-catalyzed dearomative allylic alkylation of indoles with alkynes to construct indolenines with C3-quarternary centers was reported. The in situ formed arylallene intermediate omitted the need to install leaving groups on the allylic compounds and employ extra oxidants to oxidize the allylic C-H bonds. The reaction exhibited good functional group tolerance and high atom economy. Moreover, the reaction was further expanded to synthesize pyrroloindolines and furanoindolines. PMID:27442021

  12. Gas-phase chemistry of ruthenium and rhodium carbonyl complexes.

    Science.gov (United States)

    Cao, Shiwei; Wang, Yang; Qin, Zhi; Fan, Fangli; Haba, Hiromitsu; Komori, Yukiko; Wu, Xiaolei; Tan, Cunmin; Zhang, Xin

    2016-01-01

    Short-lived ruthenium and rhodium isotopes were produced from a (252)Cf spontaneous fission (SF) source. Their volatile carbonyl complexes were formed in gas-phase reactions in situ with the carbon-monoxide containing gas. A gas-jet system was employed to transport the volatile carbonyls from the recoil chamber to the chemical separation apparatus. The gas-phase chemical behaviors of these carbonyl complexes were studied using an online low temperature isothermal chromatography (IC) technique. Long IC columns made up of FEP Teflon were used to obtain the chemical information of the high-volatile Ru and Rh carbonyls. By excluding the influence of precursor effects, short-lived isotopes of (109-110)Ru and (111-112)Rh were used to represent the chemical behaviours of Ru and Rh carbonyls. Relative chemical yields of about 75% and 20% were measured for Ru(CO)5 and Rh(CO)4, respectively, relative to the yields of KCl aerosols transported in Ar gas. The adsorption enthalpies of ruthenium and rhodium carbonyl complexes on a Teflon surface were determined to be around ΔHads = -33(+1)(-2) kJ mol(-1) and -36(+2)(-1) kJ mol(-1), respectively, by fitting the breakthrough curves of the corresponding carbonyl complexes with a Monte Carlo simulation program. Different from Mo and Tc carbonyls, a small amount of oxygen gas was found to be not effective for the chemical yields of ruthenium and rhodium carbonyl complexes. The general chemical behaviors of short-lived carbonyl complexes of group VI-IX elements were discussed, which can be used in the future study on the gas-phase chemistry of superheavy elements - Bh, Hs, and Mt carbonyls. PMID:26573993

  13. Protein carbonylation as a novel mechanism in redox signaling.

    Science.gov (United States)

    Wong, Chi Ming; Cheema, Amrita K; Zhang, Lihua; Suzuki, Yuichiro J

    2008-02-15

    Reactive oxygen species serve as second messengers for signal transduction; however, molecular targets of oxidant signaling have not been defined. Here, we show that ligand-receptor-mediated signaling promotes reactive oxygen species-dependent protein carbonylation. Treatment of pulmonary artery smooth muscle cells with endothelin-1 increased protein carbonyls. Carbonylation of the majority of proteins occurred transiently, suggesting that there is also a mechanism for decarbonylation induced by endothelin-1. Decarbonylation was suppressed by inhibition of thioredoxin reductase, and cellular thioredoxin was upregulated during the decarbonylation phase. These results indicate that endothelin-1 promotes oxidant signaling as well as thioredoxin-mediated reductive signaling to regulate carbonylation and decarbonylation mechanisms. In cells treated with endothelin receptor antagonists, hydrogen peroxide scavengers, or an iron chelator, we identified, via mass spectrometry, proteins that are carbonylated in a receptor- and Fenton reaction-dependent manner, including annexin A1, which promotes apoptosis and suppresses cell growth. Carbonylation of annexin A1 by endothelin-1 was followed by proteasome-dependent degradation of this protein. We propose that carbonylation and subsequent degradation of annexin A1 may play a role in endothelin-mediated cell growth and survival, important events in pulmonary vascular remodeling. Protein carbonylation in response to ligand-receptor interactions represents a novel mechanism in redox signaling.

  14. High Resolution Infrared Spectroscopy of Propargyl Alcohol-Water Complex Embedded in Helium Nanodroplets

    Science.gov (United States)

    Mani, Devendra; Pal, Nitish; Kaufmann, Matin; Schwaab, Gerhard; Havenith, Martina

    2016-06-01

    Propargyl alcohol (hereafter abbreviated as PA) is a molecule of astrophysical interest and has been probed extensively using microwave spectroscopy.1,2 It is a multifunctional molecule and offers multiple sites for hydrogen bonding interactions. Therefore, it has also attracted the attention of groups interested in weak intermolecular interactions. Recently, the Ar…PA complex3 and PA-dimer4 have been studied using microwave spectroscopy. More recently, there have been matrix-isolation infrared spectroscopic studies on PA-water5 and PA-acetylene6 complexes. In the present work, clusters of PA and water were formed in the helium nanodroplets and probed using a combination of infrared spectroscopy and mass spectrometry. Using ab-initio quantum mechanical calculations, PA-water clusters were optimised and five minimum structures were found on the potential energy hypersurface, which were used as a guidance to the experiments. We used D2O for the experiments since our laser sources at Bochum do not cover the IR spectral region of H2O. IR spectra of PA-D2O complex were recorded in the region of symmetric and antisymmetric stretches of the bound D2O. Multiple signals were found in these regions which were dependent on the concentration of PA as well as D2O. Using pickup curves most of these signals could be assigned to 1:1 PA:D2O clusters. The ab-initio calculations helped in a definitive assignment of the spectra to the different conformers of PA-D2O complex. The details will be presented in the talk. References: 1. E. Hirota, J. Mol. Spec. 26, 335 (1968). 2. J.C. Pearson and B.J. Drouin, J. Mol. Spectrosc. 234, 149 (2005). 3. D. Mani and E. Arunan, ChemPhysChem 14, 754 (2013). 4. D. Mani and E. Arunan, J. Chem. Phys. 141, 164311 (2014). 5. J. Saini, K.S. Vishwanathan, J. Mol. Struct. 1118, 147 (2016). 6. K. Sundararajan et al., J. Mol. Struct. 1121, 26 (2016).

  15. Molecular cytotoxicity mechanisms of allyl alcohol (acrolein) in budding yeast.

    Science.gov (United States)

    Golla, Upendarrao; Bandi, Goutham; Tomar, Raghuvir S

    2015-06-15

    Allyl alcohol (AA) is one of the environmental pollutants used as a herbicide and industrial chemical. AA undergoes enzymatic oxidation in vivo to form Acrolein (Acr), a highly reactive and ubiquitous environmental toxicant. The exposure to AA/Acr has detrimental effects on cells and is highly fatal. In corroboration to the current literature describing AA/Acr toxicity, this study aimed to investigate the molecular cytotoxicity mechanisms of AA/Acr using budding yeast as a eukaryotic model organism. Genome-wide transcriptome analysis of cells treated with a sublethal dose of AA (0.4 mM) showed differential regulation of approximately 30% of the yeast genome. Functional enrichment analysis of the AA transcriptome revealed that genes belong to diverse cellular processes including the cell cycle, DNA damage repair, metal homeostasis, stress response genes, ribosomal biogenesis, metabolism, meiosis, ubiquitination, cell morphogenesis, and transport. Moreover, we have identified novel molecular targets of AA/Acr through genetic screening, which belongs to oxidative stress, DNA damage repair, iron homeostasis, and cell wall integrity. This study also demonstrated the epigenetic basis of AA/Acr toxicity mediated through histone tails and chromatin modifiers. Interestingly, our study disclosed the use of pyrazole and ethanol as probable antidotes for AA intoxication. For the first time, this study also demonstrated the reproductive toxicity of AA/Acr using the yeast gametogenesis (spermatogenesis) model. Altogether, this study unravels the molecular mechanisms of AA/Acr cytotoxicity and facilitates the prediction of biomarkers for toxicity assessment and therapeutic approaches. PMID:25919230

  16. Carbonyl-Olefin Exchange Reaction: Present State and Outlook

    Science.gov (United States)

    Kalinova, Radostina; Jossifov, Christo

    The carbonyl-olefin exchange reaction (COER) is a new reaction between carbonyl group and olefin double bond, which has a formal similarity with the olefin metathesis (OM) - one carbon atom in the latter is replaced with an oxygen atom. Till now the new reaction is performed successfully only when the two functional groups (carbonyl group and olefin double bond) are in one molecule and are conjugated. The α, β-unsaturated carbonyl compounds (substituted propenones) are the compounds with such a structure. They polymerize giving substituted polyacetylenes. The chain propagation step of this polymerization is in fact the COER. The question arises: is it possible the COER to take place when the two functional groups are not in one molecule and are not conjugated, and could this reaction became an alternative of the existing carbonyl olefination reactions?

  17. Metal-free carbonylations by photoredox catalysis.

    Science.gov (United States)

    Majek, Michal; Jacobi von Wangelin, Axel

    2015-02-01

    The synthesis of benzoates from aryl electrophiles and carbon monoxide is a prime example of a transition-metal-catalyzed carbonylation reaction which is widely applied in research and industrial processes. Such reactions proceed in the presence of Pd or Ni catalysts, suitable ligands, and stoichiometric bases. We have developed an alternative procedure that is free of any metal, ligand, and base. The method involves a redox reaction driven by visible light and catalyzed by eosin Y which affords alkyl benzoates from arene diazonium salts, carbon monoxide, and alcohols under mild conditions. Tertiary esters can also be prepared in high yields. DFT calculations and radical trapping experiments support a catalytic photoredox pathway without the requirement for sacrificial redox partners.

  18. Gas-phase chemistry of technetium carbonyl complexes.

    Science.gov (United States)

    Wang, Yang; Qin, Zhi; Fan, Fang-Li; Haba, Hiromitsu; Komori, Yukiko; Cao, Shi-Wei; Wu, Xiao-Lei; Tan, Cun-Min

    2015-05-28

    Gas-phase chemical behaviors of short-lived technetium carbonyl complexes were studied using a low temperature isothermal chromatograph (IC) coupled with a (252)Cf spontaneous fission (SF) source. Fission products recoiled from the (252)Cf SF source were thermalized in a mixed gas containing CO, and then technetium carbonyl complexes were formed from reactions between CO gas and various technetium isotopes. A gas-jet system was employed to transport the volatile carbonyl complexes from a recoil chamber to the IC. Short IC columns made of Fluorinated Ethylene Propylene (FEP) Teflon and quartz were used to obtain chemical information about the technetium carbonyl complexes. The results for the (104)Tc-(106)Tc carbonyl complexes were found to be strongly influenced by the precursors, and showed the chemical behaviors of (104)Mo-(106)Mo carbonyl complexes, respectively. However, (107)Tc and (108)Tc could represent the chemical information of the element technetium due to their high independent yields and the very short half-lives of their precursors (107)Mo and (108)Mo. An adsorption enthalpy of about ΔHads = -43 kJ mol(-1) was determined for the Tc carbonyl complexes on both the Teflon and quartz surfaces by fitting the breakthrough curves of the (107)Tc and (108)Tc carbonyl complexes with a Monte Carlo simulation program. Chemical yields of around 25% were measured for the Tc carbonyl complexes relative to the transport yields obtained with the gas-jet transport of KCl aerosol particles with Ar carrier gas. Furthermore, the influence of a small amount of O2 gas on the yields of the Mo and Tc carbonyl complexes was studied. PMID:25920667

  19. Carbonyl Emissions From Oil and Gas Production Facilities

    Science.gov (United States)

    Lyman, S. N.; O'Neil, T.; Tran, T.

    2015-12-01

    A number of recent studies have targeted emissions of methane and other hydrocarbons from oil and gas exploration and production activity. These measurements are greatly increasing understanding of the atmospheric impacts of oil and gas development. Very few measurements exist, however, of emissions of formaldehyde and other carbonyls from oil and gas equipment. Carbonyls are toxic and serve as important ozone precursors, especially during winter ozone episodes in places like Utah's Uintah Basin. Current air quality models are only able to reproduce observed high wintertime ozone if they incorporate emissions inventories with very high carbonyl emissions. We measured carbonyl emissions from oil and gas equipment and facilities—including glycol dehydrators, liquid storage tanks, raw gas leaks, raw gas-burning engines, and produced water surface impoundments—in Rocky Mountain oil and gas fields. Carbonyl emissions from raw gas were below detection, but emissions of formaldehyde, acetaldehyde, and other carbonyls were detected from liquid storage tanks, glycol dehydrators, and other oil and gas equipment. In some cases, carbonyls may be formed from the degradation of methanol and other chemicals used in oil and gas production, but the collected data provide evidence for other non-combustion formation pathways. Raw gas-burning engines also emitted carbonyls. Emissions from all measured sources were a small fraction of total volatile organic compound emissions. We incorporated our measurements into an emissions inventory, used that inventory in an air quality model (WRF-SMOKE-CAMx), and were unable to reproduce observed high wintertime ozone. This could be because (1) emission sources we have not yet measured, including compressors, gas processing plants, and others, are large; (2) non-carbonyl emissions, especially those that quickly degrade into carbonyls during photochemical processing, are underestimated in the inventory; or (3) the air quality model is unable

  20. Differential inhibition of cytochromes P450 3A4 and 3A5 by the newly synthesized coumarin derivatives 7-coumarin propargyl ether and 7-(4-trifluoromethyl)coumarin propargyl ether.

    Science.gov (United States)

    Sridar, Chitra; Kent, Ute M; Noon, Kate; McCall, Alecia; Alworth, Bill; Foroozesh, Maryam; Hollenberg, Paul F

    2008-11-01

    The abilities of 7-coumarin propargyl ether (CPE) and 7-(4-trifluoromethyl)coumarin propargyl ether (TFCPE) to act as mechanism-based inactivators of P450 3A4 and 3A5 in the reconstituted system have been investigated using 7-benzyloxy-4-(trifluoromethyl)coumarin (BFC) and testosterone as probes. CPE inhibited the BFC O-debenzylation activity of P450 3A4 in a time-, concentration-, and NADPH-dependent manner characteristic of a mechanism-based inactivator with a half-maximal inactivation (K(I)) of 112 microM, a maximal rate of inactivation (k(inact)) of 0.05 min(-1), and a t(1/2) of 13.9 min. Similarly, TFCPE inhibited the BFC O-debenzylation activity of P450 3A4 in a time-, concentration-, and NADPH-dependent manner with a K(I) of 14 microM, a k(inact) of 0.04 min(-1), and a t(1/2) of 16.5 min. Parallel losses of P450 3A4 enzymatic activity and heme were observed with both compounds as measured by high-performance liquid chromatography and reduced CO spectra. Interestingly, neither compound inhibited the BFC O-debenzylation activity of P450 3A5. Reactive intermediates of CPE and TFCPE formed by P450 3A4 were trapped with glutathione, and the resulting adducts were identified using tandem mass spectral analysis. Metabolism studies using TFCPE resulted in the identification of a single metabolite that is formed by P450 3A4 but not by P450 3A5 and that may play a role in the mechanism-based inactivation.

  1. Rapid formation of β-allyl substituted isotetronic acid derivatives via Claisen rearrangement using a microfludic device

    Institute of Scientific and Technical Information of China (English)

    Xia Ping Ma; Zhi Ming Li; Quan Rui Wang

    2011-01-01

    The thermal Claisen rearrangement of O-allyl substituted isotetronic acids 1 was successfully carried out within a glass microreactor operated with temperature at 150 ℃ and a flow rate of 1 mL/h. The strategy provides an efficient alternative way to β-allyl substituted isotetronic acid derivatives 2 in high yields with much accelerated reaction speed.

  2. Dicyano-Functionalized MCM-41-Supported Palladium Complex as An Efficient Catalyst for Allylation of Aldehydes and Ketones

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; CAI Ming-Zhong

    2006-01-01

    Dicyano-functionalized MCM-41-supported palladium complex was prepared from dicyano-functionalized MCM-41 and palladium chloride. This complex exhibited high catalytic activity in the allylation of aldehydes and ketones with allylic chlorides in the presence of SnCl2. This polymeric palladium complex can be recovered and reused without noticeable loss of activity.

  3. How phenyl makes a difference: mechanistic insights into the ruthenium( ii )-catalysed isomerisation of allylic alcohols

    KAUST Repository

    Manzini, Simone

    2013-10-16

    [RuCl(η5-3-phenylindenyl)(PPh3)2] (1) has been shown to be a highly active catalyst for the isomerisation of allylic alcohols to the corresponding ketones. A variety of substrates undergo the transformation, typically with 0.25-0.5 mol% of catalyst at room temperature, outperforming commonly-used complexes such as [RuCl(Cp)(PPh3) 2] and [RuCl(η5-indenyl)(PPh3) 2]. Mechanistic experiments and density functional theory have been employed to investigate the mechanism and understand the effect of catalyst structure on reactivity. These investigations suggest a oxo-π-allyl mechanism is in operation, avoiding intermediate ruthenium hydride complexes and leading to a characteristic 1,3-deuterium shift. Important mechanistic insights from DFT and experiments also allowed for the design of a protocol that expands the scope of the transformation to include primary allylic alcohols. © 2013 The Royal Society of Chemistry.

  4. Palladium-Mediated Dealkylation of N-Propargyl-Floxuridine as a Bioorthogonal Oxygen-Independent Prodrug Strategy

    Science.gov (United States)

    Weiss, Jason T.; Carragher, Neil O.; Unciti-Broceta, Asier

    2015-03-01

    Herein we report the development and biological screening of a bioorthogonal palladium-labile prodrug of the nucleoside analogue floxuridine, a potent antineoplastic drug used in the clinic to treat advanced cancers. N-propargylation of the N3 position of its uracil ring resulted in a vast reduction of its biological activity (~6,250-fold). Cytotoxic properties were bioorthogonally rescued in cancer cell culture by heterogeneous palladium chemistry both in normoxia and hypoxia. Within the same environment, the reported chemo-reversible prodrug exhibited up to 1,450-fold difference of cytotoxicity whether it was in the absence or presence of the extracellular palladium source, underlining the precise modulation of bioactivity enabled by this bioorthogonally-activated prodrug strategy.

  5. A New HPLC Method to Determine Carbonyl Compounds in Air

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, a new HPLC method was established to determine the carbonyl compounds in air. As the absorbent, 2, 4-dinitrophenylhydrazine (2, 4-DNPH) reacted with carbonyls specifically, which form the corresponding 2,4-dinitrophenylhydrazones, then analyzed by HPLC. The chromatographic conditions, the recovery rate, stability of samples, reagent blank, sampling efficiency were all studied systematically. The results showed that this established method had high sensitivity and good selectivity compared with other analytical methods, and it can determine ten carbonyl compounds in air in 26 min simultaneously.

  6. Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

    Directory of Open Access Journals (Sweden)

    Antonio Monopoli

    2015-06-01

    Full Text Available The Pd–benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.

  7. Chemoselective and stereoselective lithium carbenoid mediated cyclopropanation of acyclic allylic alcohols.

    Science.gov (United States)

    Durán-Peña, M J; Flores-Giubi, M E; Botubol-Ares, J M; Harwood, L M; Collado, I G; Macías-Sánchez, A J; Hernández-Galán, R

    2016-03-01

    The reaction of geraniol with different lithium carbenoids generated from n-BuLi and the corresponding dihaloalkane has been evaluated. The reaction occurs in a chemo and stereoselective manner, which is consistent with a directing effect from the oxygen of the allylic moiety. Furthermore, a set of polyenes containing allylic hydroxyl or ether groups were chemoselectively and stereoselectively converted into the corresponding gem-dimethylcyclopropanes in one single step in moderate to good yields mediated by a lithium carbenoid generated in situ by the reaction of n-BuLi and 2,2-dibromopropane.

  8. One-pot synthesis and characterization of a new, branched polycarbosilane bearing allyl groups

    Institute of Scientific and Technical Information of China (English)

    Tian Hua Huang; Zhao Ju Yu; Xu Min He; Mu He Huang; Li Fu Chen; Hai Ping Xia; Li Tong Zhang

    2007-01-01

    A highly branched polycarbosilane bearing allyl groups has been prepared by a one-pot synthesis with chloromethyltrichlorosilane, chloromethylmethyldichlorosilane and allyl chloride as the starting materials.The resultant polymer, with the approximate formula [SiH1.2(CH)30.71(CH2CH=CH2)0.09CH2]n,has been characterized by 1H, 13C, and 29Si NMR, GPC, TG and elemental analysis.It could be cross-linked thermally at 170℃ in the absence of oxygen.Pyrolysis of the polymer gave a ceramic with a yield of about 70%.

  9. Synthesis of (-)-Piperitylmagnolol Featuring ortho-Selective Deiodination and Pd-Catalyzed Allylation.

    Science.gov (United States)

    Ikoma, Atsushi; Ogawa, Narihito; Kondo, Daiki; Kawada, Hiroki; Kobayashi, Yuichi

    2016-05-01

    A 1,4-addition strategy using an enone and a copper reagent was studied for the synthesis of (-)-piperitylmagnolol. A MOM-protected biphenol copper reagent was added to BF3·OEt2-activated 4-isopropylcyclohexenone, whereas 1,4-addition of protected monophenol reagents possessing an allyl group was found to be unsuccessful. The allyl group was later attached to the p-,p'-diiodo-biphenol ring by Pd-catalyzed coupling with allylborate. The aforementioned iodide was synthesized using a new method for ortho-selective deiodination of o-,p-diiodophenols. PMID:27109890

  10. Deposition of carbonyl sulphide to soils

    Science.gov (United States)

    Kluczewski, S. M.; Brown, K. A.; Bel, J. N. B.

    Carbonyl sulphide (COS) is a trace constituent of the atmosphere and is also the main form in which 35S is released from CO 2-cooled nuclear reactors. Measurements of its deposition velocity ( Vg) are therefore important for validating radiological dose models and for interpreting the role of COS in the global S cycle. The Vg of [ 35S]COS to thin layers of several contrasting soils was measured in a through-flow fumigation system. Deposition velocity was not significantly affected by soil type, although deposition to moist soil was significantly greater ( P dried soils, mean values being 5.71 × 10 -6 ms -1 and 3.06 × 10 -6 ms -1, respectively. The results obtained are about three orders of magnitude smaller than published Vg values for SO 2 to similar soils, which suggests that uptake by soils is not a major sink for atmospheric COS. The results are consistent with the hypothesis that deposition to soil of [ 35S]COS from nuclear reactors is unlikely to contribute significantly to radiation dose from the food chain pathway. The reduction in Vg observed in heat-treated soils indicates a microbial involvement in uptake. However, it seems unlikely that microbial metabolism is the rate-controlling step, since stimulation of the microflora by the addition of nutrients did not increase COS deposition.

  11. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  12. Carbonyl-Olefin Exchange Reaction and Related Chemistry

    Science.gov (United States)

    Jossifov, Christo; Kalinova, Radostina

    A new carbon—carbon double bond forming reaction (carbonyl olefin exchange reaction) mediated by transition metal catalytic systems has been discovered. The catalytic systems used (transition metal halides or oxohalides alone or in combination with Lewis acids) are active only in the case when the two reacting groups are in one molecules and are conjugated. In addition these systems accelerate other reactions which run simultaneously with the carbonyl olefin metathesis rendering a detailed investigation of the process very complicated.

  13. Targeting Reactive Carbonyl Species with Natural Sequestering Agents

    OpenAIRE

    Sung Won Hwang; Yoon-Mi Lee; Giancarlo Aldini; Kyung-Jin Yeum

    2016-01-01

    Reactive carbonyl species generated by the oxidation of polyunsaturated fatty acids and sugars are highly reactive due to their electrophilic nature, and are able to easily react with the nucleophilic sites of proteins as well as DNA causing cellular dysfunction. Levels of reactive carbonyl species and their reaction products have been reported to be elevated in various chronic diseases, including metabolic disorders and neurodegenerative diseases. In an effort to identify sequestering agents...

  14. Solvent-Controlled, Tunable β-OAc and β-H Elimination in Rh(III)-Catalyzed Allyl Acetate and Aryl Amide Coupling via C-H Activation.

    Science.gov (United States)

    Dai, Huimin; Yu, Chao; Wang, Zihao; Yan, Hong; Lu, Changsheng

    2016-07-15

    The Heck reaction between arenes and allyl acetate has led to cinnamyl derivatives and allyl products depending on the regioselectivity of β-elimination. The regioselectivity can be controlled by the solvent in the Rh(III)-catalyzed arene-allyl acetate coupling via C-H activation: (1) in THF, cinnamyl derivatives via β-H elimination were generated; (2) in MeOH, allyl products via β-OAc elimination were produced. Both routes have advantages such as excellent γ-selectivity toward allyl acetate, good to excellent yields, and broad substrate scope. PMID:27351917

  15. Carbonyl species characteristics during the evaporation of essential oils

    Science.gov (United States)

    Chiang, Hsiu-Mei; Chiu, Hua-Hsien; Lai, Yen-Ming; Chen, Ching-Yen; Chiang, Hung-Lung

    2010-06-01

    Carbonyls emitted from essential oils can affect the air quality when they are used in indoors, especially under poor ventilation conditions. Lavender, lemon, rose, rosemary, and tea tree oils were selected as typical and popular essential oils to investigate in terms of composition, thermal characteristics and fifteen carbonyl constituents. Based on thermogravimetric (TG) analysis, the activation energy was 7.6-8.3 kcal mol -1, the reaction order was in the range of 0.6-0.7 and the frequency factor was 360-2838 min -1. Formaldehyde, acetaldehyde, acetone, and propionaldehyde were the dominant carbonyl compounds, and their concentrations were 0.034-0.170 ppm. The emission factors of carbonyl compounds were 2.10-3.70 mg g -1, and acetone, propionaldehyde, acetaldehyde, and formaldehyde accounted for a high portion of the emission factor of carbonyl compounds in essential oil exhaust. Some unhealthy carbonyl species such as formaldehyde and valeraldehyde, were measured at low-temperature during the vaporization of essential oils, indicating a potential effect on indoor air quality and human health.

  16. Traditional reactive carbonyl scavengers do not prevent the carbonylation of brain proteins induced by acute glutathione depletion

    OpenAIRE

    Zheng, J; Bizzozero, O. A.

    2010-01-01

    This study investigated the effect of reactive carbonyl species (RCS)-trapping agents on the formation of protein carbonyls during depletion of brain glutathione (GSH). To this end, rat brain slices were incubated with the GSH-depletor diethyl maleate in the absence or presence of chemically different RCS scavengers (hydralazine, methoxylamine, aminoguanidine, pyridoxamine, carnosine, taurine and z-histidine hydrazide). Despite their strong reactivity towards the most common RCS, none of the ...

  17. In(OTf)3 catalyzed allylation reaction of imines with tetraallyltin

    Institute of Scientific and Technical Information of China (English)

    Xiao Ning Wei; Ling Yan Liu; Bing Wang; Wei Xing Chang; Jing Li

    2009-01-01

    In the presence of catalytic amount of In(OTf)3 (10 mol%), a series of aldimines reacted with tetraallyltin in a 2:1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol (allyl)4Sn/In(OTf)3 for simple imines was developed.

  18. Enantioselective copper catalyzed allylic alkylation using Grignard reagents; Applications in synthesis

    NARCIS (Netherlands)

    Zijl, Anthoni Wouter van

    2009-01-01

    Enantioselective copper catalyzed allylic alkylation is a powerful carbon-carbon bond forming reaction. In this thesis the development of a new catalyst for the use of Grignard reagents in this reaction is described. This catalyst is based on copper and the ligand Taniaphos. The high regio- and enan

  19. Electrochemical studies and self diffusion coefficients in cyclic ammonium based ionic liquids with allyl substituents

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tzi-Yi [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Polymer Materials, Kun Shan University, Tainan 71003, Taiwan (China); Su, Shyh-Gang [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Wang, H. Paul [Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lin, Yuan-Chung [Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Gung, Shr-Tusen; Lin, Ming-Wei [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Sun, I.-Wen, E-mail: iwsun@mail.ncku.edu.t [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China)

    2011-03-30

    Research highlights: Cyclic ammonium-based ionic liquids with allyl substituent have high conductivity. Ionic liquids with allyl substituent have wide electrochemical window. Electrochemical and self diffusion coefficients are available for comparison. The Stokes-Einstein plots of DT{sup -1} vs. {eta}{sup -1} for redox couples in ILs are evaluated. Stokes-Einstein product of ferrocene is larger than that of cobaltocenium in ILs. - Abstract: Several cyclic ammonium-based ionic liquids (ILs) with allyl substituent are synthesized, these allyl substituent ILs have high ionic conductivity (up to 4.72 mS cm{sup -1} at 30 {sup o}C) and wide electrochemical window of 5 V. The electrochemical behaviors of two organometallic redox couples Fc/Fc{sup +} (ferrocene/ferrocenium) and Cc/Cc{sup +} (cobaltocene/cobaltocenium) have been studied in these ILs, the calculated Stokes-Einstein product (D{eta} T{sup -1}) of ferrocene in ILs is larger than that of cobaltocenium in ILs. The self-diffusion coefficients of cation and anion in these ILs are studied using pulsed gradient spin-echo NMR technique. There are very few reports where electrochemically derived diffusion coefficients and self diffusion coefficients are available for comparison, so a new key concept in electrochemistry could be developed in this paper.

  20. Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins

    Directory of Open Access Journals (Sweden)

    Hang Zhang

    2012-08-01

    Full Text Available The investigation of a Lewis base catalyzed asymmetric allylic amination of Morita–Baylis–Hillman carbonates derived from isatins afforded an electrophilic pathway to access multifunctional oxindoles bearing a C3-quaternary stereocenter, provided with good to excellent enantioselectivity (up to 94% ee and in high yields (up to 97%.

  1. Zirconium-allyl complexes as resting states in zirconocene-catalyzed α-olefin polymerization.

    Science.gov (United States)

    Panchenko, Valentina N; Babushkin, Dmitrii E; Brintzinger, Hans H

    2015-01-01

    UV-vis spectroscopic data indicate that zirconocene cations with Zr-bound allylic chain ends are generally formed during olefin polymerization with zirconocene catalysts. The rates and extent of their formation and of their re-conversion to the initial pre-catalyst cations depend on the types of zirconocene complexes and activators used.

  2. Synthesis of telechelic vinyl/allyl functional siloxane copolymers with structural control

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Javakhishvili, Irakli; Jensen, Rasmus Egekjær;

    2014-01-01

    Multifunctional siloxane copolymers with terminal vinyl or allyl functional groups are synthesised through the borane-catalysed polycondensation of hydrosilanes and alkoxysilanes. Copolymers of varying mole- cular weights ( M ̄ w =13200 – 70 300 g mol − 1 ), spatially well-distributed functional...

  3. Allylic and benzylic sp3 C-H oxidation in water.

    Science.gov (United States)

    Ang, Wei Jie; Lam, Yulin

    2015-01-28

    A copper-catalyzed method for the oxidation of allylic and benzylic sp(3) C-H by aqueous tert-butyl hydroperoxide (T-Hydro) in water using a recyclable fluorous ligand has been developed. The reaction procedure is tolerant to additional functional groups and the fluorous ligand could be reused with little loss of catalytic activity. PMID:25412371

  4. Polystyrene-supported Selenides and Selenoxide:Versatile Routes to Synthesize Allylic Alcohols

    Institute of Scientific and Technical Information of China (English)

    Wei Ming XU; You Chu ZHANG; Xian HUANG

    2003-01-01

    Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, followed by selenoxide syn-elimination and [2,3] sigmatropic rearrangement respectively to give Z-allylic alcohols stereoselectively.

  5. Silylene-mediated ring contraction of homoallylic ethers to form allylic silanes.

    Science.gov (United States)

    Bourque, Laura E; Haile, Pamela A; Woerpel, K A

    2009-09-18

    (-)-Isopulegol derivatives undergo a ring contraction under silylene-mediated conditions to provide cyclopentane products. Silylene transfer to other homoallylic ethers did not provide the ring contraction products. Allylic silane products were elaborated to determine the stereochemical course of the ring contraction reaction. A mechanism for the transformation is proposed. PMID:19681592

  6. The Wacker oxidation of allyl alcohol along cyclic-intermediate routes: An ab initio molecular dynamics investigation

    Science.gov (United States)

    Imandi, Venkataramana; Nair, Nisanth N.

    2016-09-01

    The absence of isotope scrambling observed by Henry and coworkers in the Wacker oxidation of deuterated allylic alcohol was used by them as support for the inner-sphere mechanism hydroxypalladation mechanism. One of the assumptions used to interpret their experimental data was that allyl alcohol oxidation takes place through non-cyclic intermediate routes as in the case of ethene. Here we verify this assumption through ab initio metadynamics simulations of the Wacker oxidation of allyl alcohol in explicit solvent. Importance of our results in interpreting the isotope scrambling experiments is discussed.

  7. Gold(I)-Catalyzed Intramolecular Hydroamination of N-Allylic,N′-Aryl Ureas to form Imidazolidin-2-ones

    OpenAIRE

    Li, Hao; Song, Feijie; Widenhoefer, Ross A.

    2011-01-01

    Treatment of N-allylic,N′-aryl ureas with a catalytic 1:1 mixture of di-tert-butyl-o-biphenylphoshphine gold(I) chloride and silver hexafluorophosphate (1 mol %) in chloroform at room temperature led to 5-exo hydroamination to form the corresponding imidazolidin-2-ones in excellent yield. In the case of N-allylic ureas that possessed an allylic alkyl, benzyloxymethyl, or acetoxymethyl substituent, gold(I)-catalyzed 5-exo hydroamination leads to formation of the corresponding trans-3,4-disubst...

  8. Gold(I)-Catalyzed Intramolecular Hydroamination of N-Allylic,N'-Aryl Ureas to form Imidazolidin-2-ones.

    Science.gov (United States)

    Li, Hao; Song, Feijie; Widenhoefer, Ross A

    2011-04-18

    Treatment of N-allylic,N'-aryl ureas with a catalytic 1:1 mixture of di-tert-butyl-o-biphenylphoshphine gold(I) chloride and silver hexafluorophosphate (1 mol %) in chloroform at room temperature led to 5-exo hydroamination to form the corresponding imidazolidin-2-ones in excellent yield. In the case of N-allylic ureas that possessed an allylic alkyl, benzyloxymethyl, or acetoxymethyl substituent, gold(I)-catalyzed 5-exo hydroamination leads to formation of the corresponding trans-3,4-disubstituted imidazolidin-2-ones in excellent yield with ≥50:1 diastereoselectivity. PMID:21709731

  9. Clinical features of schizophrenia with enhanced carbonyl stress.

    Science.gov (United States)

    Miyashita, Mitsuhiro; Arai, Makoto; Kobori, Akiko; Ichikawa, Tomoe; Toriumi, Kazuya; Niizato, Kazuhiro; Oshima, Kenichi; Okazaki, Yuji; Yoshikawa, Takeo; Amano, Naoji; Miyata, Toshio; Itokawa, Masanari

    2014-09-01

    Accumulating evidence suggests that advanced glycation end products, generated as a consequence of facilitated carbonyl stress, are implicated in the development of a variety of diseases. These diseases include neurodegenerative illnesses, such as Alzheimer disease. Pyridoxamine is one of the 3 forms of vitamin B6, and it acts by combating carbonyl stress and inhibiting the formation of AGEs. Depletion of pyridoxamine due to enhanced carbonyl stress eventually leads to a decrease in the other forms of vitamin B6, namely pyridoxal and pyridoxine. We previously reported that higher levels of plasma pentosidine, a well-known biomarker for advanced glycation end products, and decreased serum pyridoxal levels were found in a subpopulation of schizophrenic patients. However, there is as yet no clinical characterization of this subset of schizophrenia. In this study, we found that these patients shared many clinical features with treatment-resistant schizophrenia. These include a higher proportion of inpatients, low educational status, longer durations of hospitalization, and higher doses of antipsychotic medication, compared with patients without carbonyl stress. Interestingly, psychopathological symptoms showed a tendency towards negative association with serum vitamin B6 levels. Our results support the idea that treatment regimes reducing carbonyl stress, such as supplementation of pyridoxamine, could provide novel therapeutic benefits for this subgroup of patients. PMID:24062594

  10. Vibronic spectra of the allyl radical at 6-8 eV with resonance-enhanced multiphoton ionization technique

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The allyl radical was produced in molecular beam by pyrolysis of allyl iodide. The vibronic spectra from ground state to six new electronic states of the allyl radical at 6-8 eV, p?3dxz , p?3dxy, and p?ns (n=4, 6, 7, 8) were observed firstly with the aid of time-of-flight mass spectroscopy and resonance-enhanced multiphoton ionization technique. Vibrational progression of n7 (C3 bend) with gross spacing of about 430 cm-1 was observed in ns Rydberg states. The adiabatic ionization potential of the allyl radical was obtained to be (65641 ± 20) cm-1 ((8.138 ± 0.002) eV) by fitting the term values of ns (n=4,6,7,8) Rydberg states with Rydberg formula.

  11. Comparison of antimicrobial properties of monoterpenes and their carbonylated products.

    Science.gov (United States)

    Naigre, R; Kalck, P; Roques, C; Roux, I; Michel, G

    1996-06-01

    Some monoterpenes and their carbonylated products were evaluated for their antibacterial and antifungal properties. The carbonylation of tested monoterpenes was shown to increase the bacteriostatic and fungistatic activities specifically by the contact method. Concerning the killing effects, only (1R,2S,5R)-isopulegol, its carbonylated products, and (R)-carvone showed significant bactericidal activities, particularly against Enterococcus faecium and Escherichia coli above a concentration of 10 microliters/ml. A fungicidal efficiency of (1R,2S,5R)-isopulegol and (R)-carvone against Aspergillus niger was also noted. It seems that the presence of an oxygenated function in the framework increases the antimicrobial properties. However, monoterpenes were more active using a micro-atmosphere method. PMID:8693045

  12. Traditional reactive carbonyl scavengers do not prevent the carbonylation of brain proteins induced by acute glutathione depletion.

    Science.gov (United States)

    Zheng, J; Bizzozero, O A

    2010-03-01

    This study investigated the effect of reactive carbonyl species (RCS)-trapping agents on the formation of protein carbonyls during depletion of brain glutathione (GSH). To this end, rat brain slices were incubated with the GSH-depletor diethyl maleate in the absence or presence of chemically different RCS scavengers (hydralazine, methoxylamine, aminoguanidine, pyridoxamine, carnosine, taurine and z-histidine hydrazide). Despite their strong reactivity towards the most common RCS, none of the scavengers tested, with the exception of hydralazine, prevented protein carbonylation. These findings suggest that the majority of protein-associated carbonyl groups in this oxidative stress paradigm do not derive from stable lipid peroxidation products like malondialdehyde (MDA), acrolein and 4-hydroxynonenal (4-HNE). This conclusion was confirmed by the observation that the amount of MDA-, acrolein- and 4-HNE-protein adducts does not increase upon GSH depletion. Additional studies revealed that the efficacy of hydralazine at preventing carbonylation was due to its ability to reduce oxidative stress, most likely by inhibiting mitochondrial production of superoxide and/or by scavenging lipid free radicals. PMID:20001647

  13. Crystal Structures of Trimethoprim-Resistant DfrA1 Rationalize Potent Inhibition by Propargyl-Linked Antifolates.

    Science.gov (United States)

    Lombardo, Michael N; G-Dayanandan, Narendran; Wright, Dennis L; Anderson, Amy C

    2016-02-12

    Multidrug-resistant Enterobacteriaceae, notably Escherichia coli and Klebsiella pneumoniae, have become major health concerns worldwide. Resistance to effective therapeutics is often carried by class I and II integrons that can confer insensitivity to carbapenems, extended spectrum β-lactamases, the antifolate trimethoprim, fluoroquinolones, and aminoglycosides. Specifically of interest to the study here, a prevalent gene (dfrA1) coding for an insensitive dihydrofolate reductase (DHFR) confers 190- or 1000-fold resistance to trimethoprim for K. pneumoniae and E. coli, respectively. Attaining inhibition of both the wild-type and resistant forms of the enzyme is critical for new antifolates. For several years, we have been developing the propargyl-linked antifolates (PLAs) as effective inhibitors against trimethoprim-resistant DHFR enzymes. Here, we show that the PLAs are active against both the wild-type and DfrA1 DHFR proteins. We report two high-resolution crystal structures of DfrA1 bound to potent PLAs. The structure-activity relationships and crystal structures will be critical in driving the design of broadly active inhibitors against wild-type and resistant DHFR. PMID:27624966

  14. Isolation determination of garlic allyl sulfides and their antioxidant activity%大蒜烯丙基硫化物的分离鉴定及抗氧化性

    Institute of Scientific and Technical Information of China (English)

    刘玲; 陈琭璐; 张瑶; 白冰; 纪淑娟

    2015-01-01

    through comparing the compounds of SAC, ACSO and GSAC with glutathione (GSH) to evaluate the antioxidation. SAC, ACSO and GSAC were isolated from garlic bulbs using ion-exchange chromatography and pre-HPLC (high performance liquid chromatography). Their molecular structures were identified by high performance liquid chromatography-electrospray ionization-mass/mass spectrometry (HPLC-ESI-MS/MS), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR) and specific rotatory power. SAC and ACSO which yielded the expected [M+H]+ of m/z 162.1 and 177.8 by the measurement of mass spectrometry under positive ion mode were conferred asS-allyl-L-cysteine (C6H11O2NS) andS-allyl-L-cysteine sulfoxide (C6H11O3NS) respectively compared with the data of corresponding standard. GSAC, showing the corresponding [M-H]- of m/z 288.8, was identified asγ-glutamyl-S-allyl-L-cysteine (C11H18O5N2S) by HPLC-MS. The1H NMR spectrum of SAC and ACSOindicated the presence of the cysteinyl (δ 2.96 and 3.83, 3H) and (δ 3.26 and 4.13, 3H) moieties. The13C NMR spectrum of compound SAC and ACSO showed the presence of the cysteinyl carboxyl (δ 175.6 andδ 188.0) carbons. Similarly, the1H NMR spectrum of GSAC indicated the presence of the glutamyl (δ 2.32-2.43, 2.66 and 3.46, 5H) and cysteinyl (δ 2.75 and 4.76, 3H) moieties. The13C NMR spectrum of GSACrevealed the presence of 11 magnetically nonequivalent carbon atoms, with three of them being the glutamyl carboxyl, glutamyl carbonyl and cysteinyl carboxyl (δ 182.5, 183.2 and 184.4) carbons. Meanwhile, the scavenging activity of DPPH free radical and the chelating activity of iron ion by allyl-substituted sulfides (SAC, ACSO and GSAC) were determined with reference to cysteine derivative of GSH. The scavenging activity of DPPH free radical had no significant difference between GSH (71.14%) and both of SAC (73.55%) andGSAC (72.68%). Iron ion is one of the main oxidizing auxiliaries which can initiate free radical in

  15. Enantioselective Allylic C-H Oxidation of Terminal Olefins to Isochromans by Palladium(II)/Chiral Sulfoxide Catalysis.

    Science.gov (United States)

    Ammann, Stephen E; Liu, Wei; White, M Christina

    2016-08-01

    The enantioselective synthesis of isochroman motifs has been accomplished by palladium(II)-catalyzed allylic C-H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sulfoxide-oxazoline (ArSOX) ligand. The allylic C-H oxidation reaction proceeds with the broadest scope and highest levels of asymmetric induction reported to date (avg. 92 % ee, 13 examples with greater than 90 % ee). PMID:27376625

  16. Synthetic Studies on Tricyclic Diterpenoids: Direct Allylic Amination Reaction of Isopimaric Acid Derivatives.

    Science.gov (United States)

    Timoshenko, Mariya A; Kharitonov, Yurii V; Shakirov, Makhmut M; Bagryanskaya, Irina Yu; Shults, Elvira E

    2016-02-01

    A selective synthesis of 7- or 14-nitrogen containing tricyclic diterpenoids was completed according to a strategy in which the key step was the catalyzed direct allylic amination of methyl 14α-hydroxy-15,16-dihydroisopimarate with a wide variety of nitrogenated nucleophiles. It was revealed that the selectivity of the reaction depends on the nature of nucleophile. The catalyzed reaction of the mentioned diterpenoid allylic alcohol with 3-nitroaniline, 3-(trifluoromethyl)aniline, and 4-(trifluoromethyl)aniline yield the subsequent 7α-, 7β- and 14αnitrogen-containing diterpenoids. The reaction with 2-nitroaniline, 4-nitro-2-chloroaniline, 4-methoxy-2-nitroaniline, phenylsulfamide, or tert-butyl carbamate proceeds with the formation of 7α-nitrogen-substituted diterpenoids as the main products. PMID:27308214

  17. Rheology and viscosity scaling of gelatin/1-allyl-3-methylimidazolium chloride solution

    Science.gov (United States)

    Qiao, Congde; Li, Tianduo; Zhang, Ling; Yang, Xiaodeng; Xu, Jing

    2014-05-01

    Gelatin/1-allyl-3-methylimidazolium chloride solutions are prepared by using the ionic liquid 1-allyl-3-methylimidazolium chloride as solvent. The rheological properties of the gelatin solutions have been investigated by steady shear and oscillatory shear measurements. In the steady shear measurements, the gelatin solutions with high concentration show a shear-thinning flow behavior at high shear rates, while another shear thinning region can be found in the dilute gelatin solutions at low shear rates. The overlap concentration of gelatin in [amim]Cl is 1.0 wt% and the entanglement concentration is a factor of 4 larger (4.0 wt%). The high intrinsic viscosity (295 mL/g) indicates that the gelatin chains dispersed freely in the ionic liquid and no aggregation phenomenon occurs in dilute gelatin solution. The frequency dependences of modulus changed obviously with an increase in gelatin concentration. The empirical time-temperature superposition principle holds true at the experimental temperatures.

  18. On the key role of water in the allylic activation catalysed by Pd (II) bisphosphinite complexes

    Indian Academy of Sciences (India)

    Rakesh Kumar Sharma; Ashoka G Samuelson

    2006-11-01

    Palladium and platinum complexes of bisphosphinites and bisphosphines derived from mandelic acid have been prepared and characterized. Their ability to catalyze allylation of imines with allyltributylstannane has been studied. Bisphophinite complexes of Pd (II) are shown to be ideal and they work best in the presence of one equivalent of water. The near neutral conditions employed make the catalysts suitable for a wide variety of substrates.

  19. Highly Regioselective Palladium-Catalyzed Carboxylation of Allylic Alcohols with CO2.

    Science.gov (United States)

    Mita, Tsuyoshi; Higuchi, Yuki; Sato, Yoshihiro

    2015-11-01

    Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1 atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ-unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ-butyrolactone, a known intermediate of (R)-baclofen.

  20. Iron(III) chloride catalyzed glycosylation of peracylated sugars with allyl/alkynyl alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Narayanaperumal, Senthil; Silva, Rodrigo Cesar da; Monteiro, Julia L.; Correa, Arlene G.; Paixao, Marcio W., E-mail: mwpaixao@ufscar.br [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica

    2012-11-15

    In this work, the use of ferric chloride as an efficient catalyst in glycosylation reactions of sugars in the presence of allyl and alkynyl alcohols is described. The corresponding glycosides were obtained with moderate to good yields. This new procedure presented greater selectivity when compared to classic methods found in the literature. Principal features of this simple method include non-hazardous reaction conditions, low-catalyst loading, good yields and high anomeric selectivity (author)

  1. Lewis base catalyzed enantioselective allylic hydroxylation of Morita-Baylis-Hillman carbonates with water

    KAUST Repository

    Zhu, Bo

    2011-08-19

    A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using 18O-labeling experiments. © 2011 American Chemical Society.

  2. Experimental and Kinetic Modeling Study of 2-Methyl-2-Butene: Allylic Hydrocarbon Kinetics.

    Science.gov (United States)

    Westbrook, Charles K; Pitz, William J; Mehl, Marco; Glaude, Pierre-Alexandre; Herbinet, Olivier; Bax, Sarah; Battin-Leclerc, Frederique; Mathieu, Olivier; Petersen, Eric L; Bugler, John; Curran, Henry J

    2015-07-16

    Two experimental studies have been carried out on the oxidation of 2-methyl-2-butene, one measuring ignition delay times behind reflected shock waves in a stainless steel shock tube, and the other measuring fuel, intermediate, and product species mole fractions in a jet-stirred reactor (JSR). The shock tube ignition experiments were carried out at three different pressures, approximately 1.7, 11.2, and 31 atm, and at each pressure, fuel-lean (ϕ = 0.5), stoichiometric (ϕ = 1.0), and fuel-rich (ϕ = 2.0) mixtures were examined, with each fuel/oxygen mixture diluted in 99% Ar, for initial postshock temperatures between 1330 and 1730 K. The JSR experiments were performed at nearly atmospheric pressure (800 Torr), with stoichiometric fuel/oxygen mixtures with 0.01 mole fraction of 2M2B fuel, a residence time in the reactor of 1.5 s, and mole fractions of 36 different chemical species were measured over a temperature range from 600 to 1150 K. These JSR experiments represent the first such study reporting detailed species measurements for an unsaturated, branched hydrocarbon fuel larger than iso-butene. A detailed chemical kinetic reaction mechanism was developed to study the important reaction pathways in these experiments, with particular attention on the role played by allylic C-H bonds and allylic pentenyl radicals. The results show that, at high temperatures, this olefinic fuel reacts rapidly, similar to related alkane fuels, but the pronounced thermal stability of the allylic pentenyl species inhibits low temperature reactivity, so 2M2B does not produce "cool flames" or negative temperature coefficient behavior. The connections between olefin hydrocarbon fuels, resulting allylic fuel radicals, the resulting lack of low-temperature reactivity, and the gasoline engine concept of octane sensitivity are discussed. PMID:25822578

  3. Synthesis of alkenyl boronates from allyl-substituted aromatics using an olefin cross-metathesis protocol.

    Science.gov (United States)

    Hemelaere, Rémy; Carreaux, François; Carboni, Bertrand

    2013-07-01

    An efficient synthesis of 3-aryl-1-propenyl boronates from pinacol vinyl boronic ester and allyl-substituted aromatics by cross metathesis is reported. Although the allylbenzene derivatives are prone to isomerization reaction under metathesis conditions, we found that some ruthenium catalysts are effective for this methodology. This strategy thus provides an interesting alternative approach to alkyne hydroboration, leading to the preparation of unknown compounds. Moreover, the boron substituent can be replaced by various functional groups in good yields.

  4. Surprisingly Mild Enolate-Counterion-Free Pd(0)-Catalyzed Intramolecular Allylic Alkylations

    DEFF Research Database (Denmark)

    Madec, David; Prestat, Guillaume; Martini, Elisabetta;

    2005-01-01

    Palladium-catalyzed intramolecular allylic alkylations of unsaturated EWG-activated amides can take place under phase-transfer conditions or in the presence of a crown ether. These new reaction conditions are milder and higher yielding than those previously reported. A rationalization for such an...... for such an unexpected result is put forth and validated by DFT-B3LYP calculations. The results suggest cyclization via a counterion-free (E)-enolate TS....

  5. Allyl isothiocyanate induced stress response in Caenorhabditis elegans

    OpenAIRE

    Saini AkalRachna K; Tyler Robert T; Shim Youn; Reaney Martin JT

    2011-01-01

    Abstract Background Allyl isothiocyanate (AITC) from mustard is cytotoxic; however the mechanism of its toxicity is unknown. We examined the effects of AITC on heat shock protein (HSP) 70 expression in Caenorhabditis elegans. We also examined factors affecting the production of AITC from its precursor, sinigrin, a glucosinolate, in ground Brassica juncea cv. Vulcan seed as mustard has some potential as a biopesticide. Findings An assay to determine the concentration of AITC in ground mustard ...

  6. Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

    Science.gov (United States)

    Sidera, Mireia; Fletcher, Stephen P.

    2015-11-01

    Csp2-Csp2 cross-coupling reactions between arylboronic acid and aryl halides are widely used in both academia and industry and are strategically important in the development of new agrochemicals and pharmaceuticals. Csp2-Csp3 cross-coupling reactions have been developed, but enantioselective variations are rare and simply retaining the stereochemistry is a problem. Here we report a highly enantioselective Csp2-Csp3 bond-forming method that couples arylboronic acids to racemic allyl chlorides. Both enantiomers of a cyclic chloride are converted into a single enantiomer of product via a dynamic kinetic asymmetric transformation. This Rh-catalysed method uses readily available and inexpensive building blocks and is mild and broadly applicable. For electron-deficient, electron-rich or ortho-substituted boronic acids better results are obtained with racemic allyl bromides. Oxygen substitution in the allyl halide is tolerated and the products can be functionalized to provide diverse building blocks. The approach fills a significant gap in the methods for catalytic asymmetric synthesis.

  7. The soft X-ray absorption spectrum of the allyl free radical.

    Science.gov (United States)

    Alagia, M; Bodo, E; Decleva, P; Falcinelli, S; Ponzi, A; Richter, R; Stranges, S

    2013-01-28

    The first experimental study of the X-ray absorption spectrum (XAS) of the allyl free radical, CH(2)CHCH(2), is reported. A supersonic He seeded beam of hyperthermal allyl radicals was crossed by a high resolution synchrotron radiation (SR) in the focus of a 3D ion momentum imaging time-of-flight (TOF) spectrometer to investigate the soft X-ray absorption and fragmentation processes. The XAS, recorded as Total-Ion-Yield (TIY), is dominated by C1s electron excitations from either the central carbon atom, C(C), or the two terminal carbon atoms, C(T), to the frontier orbitals, the semi-occupied-molecular-orbital (SOMO) and the lowest-unoccupied-molecular-orbital (LUMO). All of the intense features in the XAS could only be assigned with the aid of ab initio spectral simulation at the Multi-Configuration Self-Consistent-Field (MCSCF) level of theory, this level being required because of the multi-reference nature of the core-excited state wavefunctions of the open shell molecule. The ionization energies (IEs) of the singlet and triplet states of the C1s ionized allyl radical (XPS) were also calculated at the MCSCF level. PMID:23232557

  8. Nouvelles Réactions d'Allylation Radicalaire : Exploitation de la Rupture homolytique de Liaisons Carbone-Oxygène et Carbone-Carbone

    OpenAIRE

    Debien, Laurent

    2013-01-01

    This PhD thesis is divided in eight chapters. The first three bibliographic chapters present the general principles of radical chemistry, the possibility offered by the xanthate radical chemistry and a review of the radical allylation methods, main focus of this work. The three next chapters are dedicated to the exploitation of the radical allylation of allylic alcohols, recently discovered in our laboratory. The use of such a technology enabled the preparation of functionalized enol ethers, ...

  9. Formation of vesicles with an organometallic amphiphilic bilayer by supramolecular arrangement of metal carbonyl metallosurfactants

    OpenAIRE

    Parera Piella, Elisabet; Comelles, Francesc; Barnadas Rodríguez, Ramon; Suades Ortuño, Joan

    2011-01-01

    Metallo-vesicles are formed in water medium as a result of the supramolecular arrangement of molybdenum carbonyl metallosurfactants. These new kind of surfactants contain a hydrophobic metal carbonyl fragment and are easily prepared from surfactant phosphine ligands

  10. Efficient Nd Promoted Rh Catalysts for Vapor Phase Methanol Carbonylation

    Institute of Scientific and Technical Information of China (English)

    Shu Feng ZHANG; Qing Li QIAN; Ping Lai PAN; Yi CHEN; Guo Qing YUAN

    2005-01-01

    A Nd promoted-Rh catalysts supported on polymer-derived carbon beads for vapor-phase methanol carbonylation was developed. Rh-Nd bimetallic catalysts obviously have higher activity than that of supported Rh catalyst under similar reaction condition. The difference between the activity of above two catalyst systems is clearly caused by the intrinsic properties generated by the introduction of Nd.

  11. Contamination of coal benzol by carbonyl compound impurities

    Energy Technology Data Exchange (ETDEWEB)

    Yakovleva, T.P.

    1985-03-01

    The origin of most carbonyl compounds in nitration-grade benzene produced from coke-oven crude benzole (causing problems in isopropylbenzene production) was concluded to be the piperylene fraction (a by-product of isoprene manufacture) used as an additive in the washing of the benzene with sulphuric acid.

  12. Comparing Carbonyl Chemistry in Comprehensive Introductory Organic Chemistry Textbooks

    Science.gov (United States)

    Nelson, Donna J.; Kumar, Ravi; Ramasamy, Saravanan

    2015-01-01

    Learning the chemistry of compounds containing carbonyl groups is difficult for undergraduate students partly because of a convolution of multiple possible reaction sites, competitive reactions taking place at those sites, different criteria needed to discern between the mechanisms of these reactions, and no straightforward selection method…

  13. α-Carbonyl Radical Cyclizatio n in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    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. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide

    Science.gov (United States)

    Rathke, Jerome W.; Klingler, Robert J.

    1993-01-01

    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  15. Iron-Sulfur-Carbonyl and -Nitrosyl Complexes: A Laboratory Experiment.

    Science.gov (United States)

    Glidewell, Christopher; And Others

    1985-01-01

    Background information, materials needed, procedures used, and typical results obtained, are provided for an experiment on iron-sulfur-carbonyl and -nitrosyl complexes. The experiment involved (1) use of inert atmospheric techniques and thin-layer and flexible-column chromatography and (2) interpretation of infrared, hydrogen and carbon-13 nuclear…

  16. Carbonyl Sulfides as Possible Intermediates in the Photolysis of Oxathiiranes

    DEFF Research Database (Denmark)

    Carlsen, Lars; Snyder, J. P.; Holm, A.;

    1981-01-01

    species and several dipolarophiles is rationlized in terms of a labile carbonyl suffide intermediate capable of facile sulfur extrusion from a long, weak O-S bond. Finally, the electronic absorption spectra of a series of para-substituted benzaldehyde O-sulfide model system have been calculated with CNDO...

  17. Age-related variations of protein carbonyls in human saliva and plasma: is saliva protein carbonyls an alternative biomarker of aging?

    Science.gov (United States)

    Wang, Zhihui; Wang, Yanyi; Liu, Hongchen; Che, Yuwei; Xu, Yingying; E, Lingling

    2015-06-01

    Free radical hypothesis which is one of the most acknowledged aging theories was developed into oxidative stress hypothesis. Protein carbonylation is by far one of the most widely used markers of protein oxidation. We studied the role of age and gender in protein carbonyl content of saliva and plasma among 273 Chinese healthy subjects (137 females and 136 males aged between 20 and 79) and discussed the correlation between protein carbonyl content of saliva and plasma. Protein carbonyl content of saliva and plasma were, respectively, 2.391 ± 0.639 and 0.838 ± 0.274 nmol/mg. Variations of saliva and plasma different age groups all reached significant differences in both male and female (all p saliva and plasma protein carbonyls were found to be significantly correlated with age (r = 0.6582 and r = 0.5176, all p saliva and plasma protein carbonyl levels (all p > 0.05). Saliva and plasma protein carbonyls were positively related (r = 0.4405, p saliva and plasma protein carbonyls/ferric reducing ability of plasma (FRAP) ratios were proved to be significantly correlated with age (r = 0.7796 and r = 0.6938, all p saliva protein carbonyls/FRAP ratio and plasma protein carbonyls/FRAP ratio were also correlated (r = 0.5573, p saliva protein carbonyls seem to be an alternative biomarker of aging while the mechanisms of protein carbonylation and oxidative stress and the relationship between saliva protein carbonyls and diseases need to be further investigated.

  18. High throughput assay for evaluation of reactive carbonyl scavenging capacity ☆

    OpenAIRE

    N. Vidal; J.P. Cavaille; Graziani, F.; M. Robin; Ouari, O; Pietri, S.; Stocker, P.

    2014-01-01

    Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or...

  19. On the Nature of the Intermediates and the Role of Chloride Ions in Pd-Catalyzed Allylic Alkylations: Added Insight from Density Functional Theory

    DEFF Research Database (Denmark)

    Fristrup, Peter; Ahlquist, Mårten Sten Gösta; Tanner, David Ackland;

    2008-01-01

    The reactivity of intermediates in palladium-catalyzed allylic alkylation was investigated using DFT (B3LYP) calculations including a PB-SCRF solvation model. In the presence of both phosphine and chloride ligands, the allyl intermediate is in equilibrium between a cationic eta(3)-allylPd complex...... with two phosphine ligands, the corresponding neutral complex with one phosphine and one chloride ligand, and a neutral eta(1)-allylPd complex with one chloride and two phosphine ligands. The eta(1)-complex is unreactive toward nucleophiles. The cationic eta(3)-complex is the intermediate most...

  20. Plasma protein carbonyl levels and breast cancer risk.

    Science.gov (United States)

    Rossner, Pavel; Terry, Mary Beth; Gammon, Marilie D; Agrawal, Meenakshi; Zhang, Fang Fang; Ferris, Jennifer S; Teitelbaum, Susan L; Eng, Sybil M; Gaudet, Mia M; Neugut, Alfred I; Santella, Regina M

    2007-01-01

    To study the role of oxidative stress in breast cancer risk, we analysed plasma levels of protein carbonyls in 1050 cases and 1107 controls. We found a statistically significant trend in breast cancer risk in relation to increasing quartiles of plasma protein carbonyl levels (OR = 1.2, 95% CI = 0.9-1.5; OR = 1.5, 95% CI = 1.2-2.0; OR = 1.6, 95% CI = 1.2-2.1, for the 2(nd), 3(rd) and 4(th) quartile relative to the lowest quartile, respectively, P for trend = 0.0001). The increase in risk was similar for younger ( or = 15 grams/day for 4(th) quartile versus lowest quartile OR = 2.3, 95% CI = 1.1-4.7), and hormone replacement therapy use (HRT, OR = 2.6, 95% CI = 1.6-4.4 for 4(th) quartile versus lowest quartile). The multiplicative interaction terms were statistically significant only for physical activity and HRT. The positive association between plasma protein carbonyl levels and breast cancer risk was also observed when the analysis was restricted to women who had not received chemotherapy or radiation therapy prior to blood collection. Among controls, oxidized protein levels significantly increased with cigarette smoking and higher fruit and vegetable consumption, and decreased with alcohol consumption >30 grams per day. Women with higher levels of plasma protein carbonyl and urinary 15F(2t)-isoprostane had an 80% increase in breast cancer risk (OR = 1.8, 95% CI = 1.2-2.6) compared to women with levels below the median for both markers of oxidative stress. In summary, our results suggest that increased plasma protein carbonyl levels may be associated with breast cancer risk.

  1. Microwave-assisted efficient synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols and -iodophenols

    Indian Academy of Sciences (India)

    Liansheng Wu; Xiaokang Shi; Xiaoyun Xu; Fen Liang; Guosheng Huang

    2011-09-01

    A simple, efficient and expeditious method for synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols, -iodophenols and silica gel with the catalyst of PdCl2(PPh3)2 (2 mol%)/CuI (2mol%) and microwave-promoted Sonogashira coupling/cyclization reaction is developed. The methodology can produce good to excellent yields. In addition, this method can also be completed in one-pot with iodobenzene, 2-methyl-3-butyn-2-ol and 2-iodo-4-methylphenol as reactants.

  2. Communication: A vibrational study of propargyl cation using the vacuum ultraviolet laser velocity-map imaging photoelectron method

    Science.gov (United States)

    Gao, Hong; Lu, Zhou; Yang, Lei; Zhou, Jingang; Ng, C. Y.

    2012-10-01

    By employing the vacuum ultraviolet (VUV) laser velocity-map imaging photoelectron (VUV-VMI-PE) method, we have obtained a vibrationally resolved photoelectron spectrum of gaseous propargyl radical [C3H3(X2B1)] in the energy range of 0-4600 cm-1 above its ionization energy. The cold C3H3 radicals were produced from a supersonically cooled radical beam source based on 193 nm ArF photodissociation of C3H3Cl. The VUV-VMI-PE spectrum of C3H3 thus obtained reveals a Franck-Condon factor (FCF) pattern with a highly dominant origin band along with weak vibrational progressions associated with excitations of the C-C ν5+(a1) and C≡C ν3+(a1) symmetric stretching modes and the CCH ν7+(b1) out-of-plane bending mode of C3H3+(X1A1). The ν5+(a1) vibrational frequency of 1120 cm-1 determined in the present study is lower than the value deduced from the recent Ar-tagged infrared photodissociation study by 102 cm-1, confirming the highly accurate vibrational frequency predictions obtained by the most recent state-of-the-art ab initio quantum calculations. The observation of the FCF disallowed ν7+(b1) mode is indicative of vibronic interactions. The discrepancy observed between the FCF pattern determined in the present study and that predicted by a recent high-level quantum theoretical investigation can be taken as evidence that the potential energy surfaces used in the latter theoretical study are in need of improvement in order to provide a reliable FCF prediction for the C3H3/C3H3+ photoionization system.

  3. High-resolution threshold photoelectron study of the propargyl radical by the vacuum ultraviolet laser velocity-map imaging method

    Science.gov (United States)

    Gao, Hong; Xu, Yuntao; Yang, Lei; Lam, Chow-Shing; Wang, Hailing; Zhou, Jingang; Ng, C. Y.

    2011-12-01

    By employing the vacuum ultraviolet (VUV) laser velocity-map imaging (VMI) photoelectron scheme to discriminate energetic photoelectrons, we have measured the VUV-VMI-threshold photoelectrons (VUV-VMI-TPE) spectra of propargyl radical [C3H3({tilde X}{}^2B_1)] near its ionization threshold at photoelectron energy bandwidths of 3 and 7 cm-1 (full-width at half-maximum, FWHM). The simulation of the VUV-VMI-TPE spectra thus obtained, along with the Stark shift correction, has allowed the determination of a precise value 70 156 ± 4 cm-1 (8.6982 ± 0.0005 eV) for the ionization energy (IE) of C3H3. In the present VMI-TPE experiment, the Stark shift correction is determined by comparing the VUV-VMI-TPE and VUV laser pulsed field ionization-photoelectron (VUV-PFI-PE) spectra for the origin band of the photoelectron spectrum of the {tilde X}^ + {- tilde X} transition of chlorobenzene. The fact that the FWHMs for this origin band observed using the VUV-VMI-TPE and VUV-PFI-PE methods are nearly the same indicates that the energy resolutions achieved in the VUV-VMI-TPE and VUV-PFI-PE measurements are comparable. The IE(C3H3) value obtained based on the VUV-VMI-TPE measurement is consistent with the value determined by the VUV laser PIE spectrum of supersonically cooled C3H3({tilde X}{}^2B_1) radicals, which is also reported in this article.

  4. Protein carbonylation and metal-catalyzed protein oxidation in a cellular perspective

    DEFF Research Database (Denmark)

    Møller, Ian Max; Rogowska-Wrzesinska, Adelina; Rao, R S P

    2011-01-01

    to be relevant in physiological processes, irreversible oxidative modifications are known to contribute to cellular damage and disease. The most well-studied irreversible protein oxidation is carbonylation. In this work we first examine how protein carbonylation occurs via metal-catalyzed oxidation (MCO) in vivo...... and in vitro with an emphasis on cellular metal ion homeostasis and metal binding. We then review proteomic methods currently used for identifying carbonylated proteins and their sites of modification. Finally, we discuss the identified carbonylated proteins and the pattern of carbonylation sites in relation...

  5. Genome wide association mapping in Arabidopsis thaliana identifies novel genes involved in linking allyl glucosinolate to altered biomass and defense

    Directory of Open Access Journals (Sweden)

    Marta Francisco

    2016-07-01

    Full Text Available A key limitation in modern biology is the ability to rapidly identify genes underlying newly identified complex phenotypes. Genome wide association studies (GWAS have become an increasingly important approach for dissecting natural variation by associating phenotypes with genotypes at a genome wide level. Recent work is showing that the Arabidopsis thaliana defense metabolite, allyl glucosinolate (GSL, may provide direct feedback regulation, linking defense metabolism outputs to the growth and defense responses of the plant. However, there is still a need to identify genes that underlie this process. To start developing a deeper understanding of the mechanism(s that modulate the ability of exogenous allyl GSL to alter growth and defense, we measured changes in plant biomass and defense metabolites in a collection of natural 96 A. thaliana accessions fed with 50 µM of allyl GSL. Exogenous allyl GSL was introduced exclusively to the roots and the compound transported to the leaf leading to a wide range of heritable effects upon plant biomass and endogenous GSL accumulation. Using natural variation we conducted GWAS to identify a number of new genes which potentially control allyl responses in various plant processes. This is one of the first instances in which this approach has been successfully utilized to begin dissecting a novel phenotype to the underlying molecular/polygenic basis.

  6. New [Mo(eta3-allyl)(CO)2L3]+ complexes with monodentate or tridentate nitrogen-donor ligands.

    Science.gov (United States)

    Pérez, Julio; Morales, Dolores; Nieto, Sonia; Riera, Lucía; Riera, Víctor; Miguel, Daniel

    2005-03-01

    Cationic complexes [Mo(eta(3)-allyl)(CO)2L3]+ (L3 = either nitrogen-donor tridentate ligand or three monodentate ligands) were prepared in high yield and under mild conditions using as precursors either the triflato complex [Mo(eta(3)-allyl)(OTf)(CO)2(NCMe)2] or the combination of the chloro complex [Mo(eta(3)-allyl)Cl(CO)2(NCMe)2] and the salt NaBAr'(4)(Ar'= 3,5-bis(trifluoromethyl)phenyl). The tridentate ligands employed were 2,2':6',2'-terpyridine (terpy) and cis,cis-1,3,5-cyclohexanetriamine (CHTA), whereas the monodentate ligands imidazole (im) and 3,5-dimethylpyrazole (dmpz) were chosen. In order to stabilize the labile intermediates, an excess of acetonitrile was used in most of the syntheses. However, the pyrazole complex was prepared through a nitrile-free route to avoid reactions at the coordinated nitrile. The solid state structures of [Mo(eta(3)-methallyl)(CO)2(terpy)]OTf (2), [Mo(eta(3)-methallyl)(CO)2(CHTA)]BAr'4 (3), [Mo(eta(3)-methallyl)(CO)2(NCMe)3]BAr'4 (4), [Mo(eta(3)-allyl)(CO)2(im)3]OTf (5) and [Mo(eta(3)-allyl)(CO)2(dmpz)3]BAr'4 (6) were determined by means of single-crystal X-ray diffraction. PMID:15726140

  7. Phenolic carbonyls undergo rapid aqueous photodegradation to form low-volatility, light-absorbing products

    Science.gov (United States)

    Smith, Jeremy D.; Kinney, Haley; Anastasio, Cort

    2016-02-01

    We investigated the aqueous photochemistry of six phenolic carbonyls - vanillin, acetovanillone, guaiacyl acetone, syringaldehyde, acetosyringone, and coniferyl aldehyde - that are emitted from wood combustion. The phenolic carbonyls absorb significant amounts of solar radiation and decay rapidly via direct photodegradation, with lifetimes (τ) of 13-140 min under Davis, CA winter solstice sunlight at midday (solar zenith angle = 62°). The one exception is guaiacyl acetone, where the carbonyl group is not directly connected to the aromatic ring: This species absorbs very little sunlight and undergoes direct photodegradation very slowly (τ > 103 min). We also found that the triplet excited states (3C*) of the phenolic carbonyls rapidly oxidize syringol (a methoxyphenol without a carbonyl group), on timescales of 1-5 h for solutions containing 5 μM phenolic carbonyl. The direct photodegradation of the phenolic carbonyls, and the oxidation of syringol by 3C*, both efficiently produce low volatility products, with SOA mass yields ranging from 80 to 140%. Contrary to most aliphatic carbonyls, under typical fog conditions we find that the primary sink for the aromatic phenolic carbonyls is direct photodegradation in the aqueous phase. In areas of significant wood combustion, phenolic carbonyls appear to be small but significant sources of aqueous SOA: over the course of a few hours, nearly all of the phenolic carbonyls will be converted to SOA via direct photodegradation, enhancing the POA mass from wood combustion by approximately 3-5%.

  8. Preparation of Well-Defined Propargyl-Terminated Tetra-Arm Poly(N-isopropylacrylamides and Their Click Hydrogels Crosslinked with β-cyclodextrin

    Directory of Open Access Journals (Sweden)

    Jianquan Wang

    2016-03-01

    Full Text Available As an important class of reversible deactivation radical polymerization (RDRP, reversible addition fragmentation chain transfer (RAFT polymerization has attracted great attention attributed to its facile and flexible features to prepare well-defined polymers with different complex structures. In addition, the combination of RAFT with click chemistry provides more effective strategies to fabricate advanced functional materials. In this work, a series of temperature responsive tetra-arm telechelic poly(N-isopropylacrylamides (PNIPAs with propargyl end groups were prepared for the first time through RAFT and subsequent aminolysis/Michael addition modification. The temperature sensitivities of their aqueous solutions were researched via turbidity measurement. It was found that the phase transition temperature of obtained PNIPAs increased with their molecular weights ascribed to their distinctions in the hydrophobic/hydrophilic balance. Subsequently, β-cyclodextrin (β-CD functionalized with azide moieties was used to crosslink the prepared propargyl-terminated tetra-arm PNIPAs through click chemistry, fabricating corresponding hydrogels with thermoresponse. Similar to their precursors, the hydrogels demonstrated the same dependence of volume phase transition temperature (VPTT on their molecular weights. In addition, the incorporation of β-CD and the residual groups besides crosslinking may provide a platform for imparting additional functions such as inclusion and adsorption as well as further functionalization.

  9. [Carbonyl stress and oxidatively modified proteins in chronic renal failure].

    Science.gov (United States)

    Bargnoux, A-S; Morena, M; Badiou, S; Dupuy, A-M; Canaud, B; Cristol, J-P

    2009-01-01

    Oxidative stress is commonly observed in chronic renal failure patients resulting from an unbalance between overproduction of reactive oxygen species and impairement of defense mechanisms. Proteins appear as potential targets of uremia-induced oxidative stress and may undergo qualitative modifications. Proteins could be directly modified by reactive oxygen species which leads to amino acid oxydation and cross-linking. Proteins could be indirectly modified by reactive carbonyl compounds produced by glycoxidation and lipo-peroxidation. The resulting post-traductional modifications are known as carbonyl stress. In addition, thiols could be oxidized or could react with homocystein leading to homocysteinylation. Finally, tyrosin could be oxidized by myeloperoxidase leading to advanced oxidative protein products (AOPP). Oxidatively modified proteins are increased in chronic renal failure patients and may contribute to exacerbate the oxidative stress/inflammation syndrome. They have been involved in long term complications of uremia such as amyloidosis and accelerated atherosclerosis. PMID:19297289

  10. Role of Carbonyl Modifications on Aging-Associated Protein Aggregation

    Science.gov (United States)

    Tanase, Maya; Urbanska, Aleksandra M.; Zolla, Valerio; Clement, Cristina C.; Huang, Liling; Morozova, Kateryna; Follo, Carlo; Goldberg, Michael; Roda, Barbara; Reschiglian, Pierluigi; Santambrogio, Laura

    2016-01-01

    Protein aggregation is a common biological phenomenon, observed in different physiological and pathological conditions. Decreased protein solubility and a tendency to aggregate is also observed during physiological aging but the causes are currently unknown. Herein we performed a biophysical separation of aging-related high molecular weight aggregates, isolated from the bone marrow and splenic cells of aging mice and followed by biochemical and mass spectrometric analysis. The analysis indicated that compared to younger mice an increase in protein post-translational carbonylation was observed. The causative role of these modifications in inducing protein misfolding and aggregation was determined by inducing carbonyl stress in young mice, which recapitulated the increased protein aggregation observed in old mice. Altogether our analysis indicates that oxidative stress-related post-translational modifications accumulate in the aging proteome and are responsible for increased protein aggregation and altered cell proteostasis.

  11. Anchoring selenido-carbonyl ruthenium clusters to functionalized silica xerogels

    Energy Technology Data Exchange (ETDEWEB)

    Cauzzi, Daniele; Graiff, Claudia; Pattacini, Roberto; Predieri, Giovanni; Tiripicchio, Antonio [Universita di Parma (Italy). Dipt. di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica]. E-mail: tiri@unipr.it

    2003-12-01

    Silica Xerogels containing carbonyl Ru{sub 3}Se{sub 2} nido clusters were prepared in three different ways. The simple dispersion of [Ru{sub 3}({mu}{sub 3}-Se){sub 2}(CO){sub 7}(PPh {sub 3}){sub 2}] via sol gel process produces an inhomogeneous material; by contrast, homogeneous xerogels were obtained by reaction of [Ru{sub 3}({mu}{sub 3}-Se){sub 2}(CO){sub 8}(PPh {sub 3})] with functionalized xerogels containing grafted diphenylphosphine moieties and by reaction of [Ru{sub 3}(CO){sub 12}] with a xerogel containing grafted phosphine-selenide groups. The reaction between [Ru{sub 3}(CO){sub 12}] and dodecyl diphenylphosphine selenide led to the formation of four selenido carbonyl clusters, which are soluble in hydrocarbon solvents and can be deposited as thin films from their solution by slow evaporation. (author)

  12. Special Topic 3B: Acidity, Basicity, and Carbonyl Condensation Reactions

    OpenAIRE

    Christiansen, Mike A

    2012-01-01

    The purpose of this video is to help second-year organic chemistry students review the concepts and questions that most frequently appear on standardized entrance exams, like the MCAT, DAT, PCAT, and GRE. I'll here teach you how to sort molecules according to acidity and basicity. I'll also review the following carbonyl condensation and related reactions: the aldol reaction, the Claisen and intramolecular diketone condensations, and the malonic ester synthesis. --Dr. Mike Christiansen from Ut...

  13. Iron(III)-catalysed carbonyl-olefin metathesis.

    Science.gov (United States)

    Ludwig, Jacob R; Zimmerman, Paul M; Gianino, Joseph B; Schindler, Corinna S

    2016-05-19

    The olefin metathesis reaction of two unsaturated substrates is one of the most powerful carbon-carbon-bond-forming reactions in organic chemistry. Specifically, the catalytic olefin metathesis reaction has led to profound developments in the synthesis of molecules relevant to the petroleum, materials, agricultural and pharmaceutical industries. These reactions are characterized by their use of discrete metal alkylidene catalysts that operate via a well-established mechanism. While the corresponding carbonyl-olefin metathesis reaction can also be used to construct carbon-carbon bonds, currently available methods are scarce and severely hampered by either harsh reaction conditions or the required use of stoichiometric transition metals as reagents. To date, no general protocol for catalytic carbonyl-olefin metathesis has been reported. Here we demonstrate a catalytic carbonyl-olefin ring-closing metathesis reaction that uses iron, an Earth-abundant and environmentally benign transition metal, as a catalyst. This transformation accommodates a variety of substrates and is distinguished by its operational simplicity, mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis. We anticipate that these characteristics, coupled with the efficiency of this reaction, will allow for further advances in areas that have historically been enhanced by olefin metathesis. PMID:27120158

  14. Iron(III)-catalysed carbonyl-olefin metathesis.

    Science.gov (United States)

    Ludwig, Jacob R; Zimmerman, Paul M; Gianino, Joseph B; Schindler, Corinna S

    2016-04-27

    The olefin metathesis reaction of two unsaturated substrates is one of the most powerful carbon-carbon-bond-forming reactions in organic chemistry. Specifically, the catalytic olefin metathesis reaction has led to profound developments in the synthesis of molecules relevant to the petroleum, materials, agricultural and pharmaceutical industries. These reactions are characterized by their use of discrete metal alkylidene catalysts that operate via a well-established mechanism. While the corresponding carbonyl-olefin metathesis reaction can also be used to construct carbon-carbon bonds, currently available methods are scarce and severely hampered by either harsh reaction conditions or the required use of stoichiometric transition metals as reagents. To date, no general protocol for catalytic carbonyl-olefin metathesis has been reported. Here we demonstrate a catalytic carbonyl-olefin ring-closing metathesis reaction that uses iron, an Earth-abundant and environmentally benign transition metal, as a catalyst. This transformation accommodates a variety of substrates and is distinguished by its operational simplicity, mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis. We anticipate that these characteristics, coupled with the efficiency of this reaction, will allow for further advances in areas that have historically been enhanced by olefin metathesis.

  15. Carbonylation of Ethene Catalysed by Pd(II-Phosphine Complexes

    Directory of Open Access Journals (Sweden)

    Gianni Cavinato

    2014-09-01

    Full Text Available This review deals with olefin carbonylation catalysed by Pd(II-phosphine complexes in protic solvents. In particular, the results obtained in the carbonylation with ethene are reviewed. After a short description of the basic concepts relevant to this catalysis, the review treats in greater details the influence of the bite angle, skeletal rigidity, electronic and steric bulk properties of the ligand on the formation of the products, which range from high molecular weight perfectly alternating polyketones to methyl propanoate. It is shown that the steric bulk plays a major role in directing the selectivity. Particular emphasis is given to the factors governing the very active and selective catalysis to methyl propanoate, including the mechanism of the catalytic cycles with diphosphine- and monophosphine-catalysts. A brief note on the synthesis of methyl propanoate using a “Lucite” type catalyst in ionic liquids is also illustrated. A chapter is dedicated to the carbonylation of olefins in aqueous reaction media. The nonalternating CO-ethene copolymerization is also treated.

  16. Iron(III)-catalysed carbonyl-olefin metathesis

    Science.gov (United States)

    Ludwig, Jacob R.; Zimmerman, Paul M.; Gianino, Joseph B.; Schindler, Corinna S.

    2016-05-01

    The olefin metathesis reaction of two unsaturated substrates is one of the most powerful carbon-carbon-bond-forming reactions in organic chemistry. Specifically, the catalytic olefin metathesis reaction has led to profound developments in the synthesis of molecules relevant to the petroleum, materials, agricultural and pharmaceutical industries. These reactions are characterized by their use of discrete metal alkylidene catalysts that operate via a well-established mechanism. While the corresponding carbonyl-olefin metathesis reaction can also be used to construct carbon-carbon bonds, currently available methods are scarce and severely hampered by either harsh reaction conditions or the required use of stoichiometric transition metals as reagents. To date, no general protocol for catalytic carbonyl-olefin metathesis has been reported. Here we demonstrate a catalytic carbonyl-olefin ring-closing metathesis reaction that uses iron, an Earth-abundant and environmentally benign transition metal, as a catalyst. This transformation accommodates a variety of substrates and is distinguished by its operational simplicity, mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis. We anticipate that these characteristics, coupled with the efficiency of this reaction, will allow for further advances in areas that have historically been enhanced by olefin metathesis.

  17. Enhanced performance of the catalytic conversion of allyl alcohol to 3-hydroxypropionic acid using bimetallic gold catalysts.

    Science.gov (United States)

    Falletta, Ermelinda; Della Pina, Cristina; Rossi, Michele; He, Qian; Kiely, Christopher J; Hutchings, Graham J

    2011-01-01

    One of the strategic building blocks in organic synthesis is 3-hydroxypropionic acid, which is particularly important for the manufacture of high performance polymers. However, to date, despite many attempts using both biological and chemical routes, no large scale effective process for manufacturing 3-hydroxypropionic acid has been developed. One potentially useful starting point is from allyl alcohol, as this can be obtained in principle from the dehydration of glycerol, thereby presenting a bio-renewable green pathway to this important building block. The catalytic transformation of allyl alcohol to 3-hydroxypropionic acid presents interesting challenges in catalyst design, particularly with respect to the control of selectivity among the products that can be expected, as acrylic acid, acrolein and glyceric acid can also be formed. In this paper, we present a novel eco-sustainable catalytic pathway leading to 3-hydroxypropionic acid, which highlights the outstanding potential of gold-based and bimetallic catalysts in the aerobic oxidation of allyl alcohol. PMID:22455056

  18. Study on the Preparation of Allyl-modified Starch in Isopropyl/Water Medium for Warp Sizing

    Institute of Scientific and Technical Information of China (English)

    LI Man-li; ZHU Zhi-feng; ZHANG Long-qiu

    2008-01-01

    A new method for the pretreatment of starch by etherification was developed to eliminate the problems of lower grafting efficiency associated with the preparation of starch graft copolymers as warp sizing agents.The etherification of starch with allyl chloride was investigated in order to effectively enhance the reaction efficiency.The technological variables of the reaction considered for evaluating the etherification included sodium hydroxide amount,water content in water-isopropyi alcohol medium,allyl cldoride concentration,reaction temperature and reaction time.The experimental result demonstrated that the variables considered showed evident effect on the reaction efficiency.For the etherification,a condition of 20% for the water content,1.5:1 for the molar ratio of sodium hydroxide to allyl chloride.and at 30℃ under 24h reaction is Sufficient to retain the reaction efficiency above 50%.Furthermore,a contrast test demonstrated that the graft efficiency can be increased with the etherification pretreatment.

  19. Thermophysical properties and reaction kinetics of γ-irradiated poly allyl diglycol carbonates nuclear track detector

    Science.gov (United States)

    Elmaghraby, Elsayed K.; Seddik, Usama

    2015-07-01

    Kinetic thermogravimetric technique was used to study the effect of gamma irradiation on the poly allyl diglycol carbonates (PADC) within the dose range from 50 to ? Gy. The approach of Coats-Redfern was used to analyze the data. Results showed that low doses around 50 Gy make the polymer slightly more resistive to heat treatment. Higher radiation doses cause severe effects in the samples accompanied by the formation of lower molecular mass species and consequent crosslinking. Results support the domination of re-polymerization and crosslinking for the γ radiation interaction PADC at dose below about ? Gy, while the situation is inverted above ? Gy in which chain secession dominates.

  20. Polymer-Supported Chiral Monodentate Phosphoramidites in Palladium-Catalyzed Allylic Alkylation Reactions

    Institute of Scientific and Technical Information of China (English)

    JIANG,Zhi-Dong; MENG,Zhao-Hai

    2007-01-01

    A new and simple method for immobilization of monodentate chiral ligand on the cheap resin has been developed.A series of resin-immobilized phosphoramidite ligands based on BINOL and TADDOL backbones have been synthesized and characterized with gel-phase NMR.The immobilized ligands have been applied to the Pd-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate.Among four ligands,the supported bulky monodentate phosphoramidite ligand based on TADDOL backbone afforded the chiral product with ee up to 65%;moreover,this ligand could be recycled for 3 times without substantial decrease of the conversion and ee.

  1. Synthesis of Aminophosphine Ligands with Binaphthyl Backbones for Silver(I)-catalyzed Enantioselective Allylation of Benzaldehyde

    Institute of Scientific and Technical Information of China (English)

    WANG,Yi(王以); JI,Bao-Ming(吉保明); DING,Kui-Ling(丁奎岭)

    2002-01-01

    A series of aminophosphine ligands was synthesized from 2amino-2′-hydroxy-1,1′-binaphthyl (NOBIN). Their asymmetric induction efficiency was examined for silver(I)catalyzed enantioselective allylation reaction of benzaldehyde with allyltributyltin.Under the optimized reaction conditions,quantitative yield as well as moderate ee value (54.5% ee)of product was achieved by the catalysis with silver(I)/3 complex. The effects of the binaphthyl backbone and the substituted situated at chelating N, Patoms on enantioselectivity of the reaction were also discussed.

  2. Mechanistic Investigation of Palladium–Catalyzed Allylic C–H Activation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Jensen, Thomas; Rodríguez-Rodríguez, Sergio;

    2013-01-01

    The mechanism for the palladium–catalyzed allylic C–H activation was investigated using a combination of experimental and theoretical methods. A Hammett study revealed a buildup of a partial negative charge in the rate-determining step, while determination of the kinetic isotope effect (KIE...... acetate acts as a base in an intramolecular fashion during the C–H activation step. The re-oxidation of palladium was found to reach a similar energy level as that of the C–H activation. Calculations of turnover frequencies (TOF) for the entire catalytic cycle for the C–H alkylation were used to acquire a...

  3. Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers

    DEFF Research Database (Denmark)

    Ambrogio, I.; Fabrizi, G.; Cacchi, S.;

    2008-01-01

    The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction tolera...... for cinnamyl ether over enol ether products. Interestingly, it was found that the product selectivity does not arise from competing beta-hydride eliminations but rather from a competition between beta-elimination and hindered single-bond rotation in the initial carbopalladation product....

  4. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    Science.gov (United States)

    DeVisscher, A.; Dewulf, J.; Van Durme, J.; Leys, C.; Morent, R.; Van Langenhove, H.

    2008-02-01

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.

  5. Lanthanum triflate triggered synthesis of tetrahydroquinazolinone derivatives of N-allyl quinolone and their biological assessment

    Directory of Open Access Journals (Sweden)

    Jardosh Hardik H.

    2012-01-01

    Full Text Available A series of 24 derivatives of tetrahydroquinazolinone has been synthesized by one-pot cyclocondensation reaction of N-allyl quinolones, cyclic β-diketones and (thiourea/N-phenylthiourea in presence of lanthanum triflate catalyst. This methodology allowed us to achieve the products in excellent yield by stirring at room temperature. All the synthesized compounds were investigated against a representative panel of pathogenic strains using broth microdilution MIC (minimum inhibitory concentration method for their in vitro antimicrobial activity. Amongst these sets of heterocyclic compounds 5h, 6b, 6h, 5f, 5l, 5n and 6g found to have admirable activity.

  6. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    International Nuclear Information System (INIS)

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation

  7. Organocatalytic Enantioselective Nucleophilic Alkynylation of Allyl Fluorides Affording Chiral Skipped Ene-ynes.

    Science.gov (United States)

    Okusu, Satoshi; Okazaki, Hiroki; Tokunaga, Etsuko; Soloshonok, Vadim A; Shibata, Norio

    2016-06-01

    Asymmetric methods for preparation of chiral alkynyl-containing compounds are in extremely high demand in many sectors of chemical research. In this work, we report the discovery of a general organocatalytic enantioselective alkynylation based on the idea of Si/F activation of the allylic C-F bond. This approach features reasonably broad substrate scope, functional group tolerance, and relatively neutral, mild, and operationally convenient reaction conditions; all of which bode well for the synthetic value of the discovered method. In particular, this method provides unique chiral skipped 1,4-ene-ynes having two kinds of versatile functional groups. PMID:27111713

  8. Combined experimental and theoretical mechanistic investigation of the Barbier allylation in aqueous media

    DEFF Research Database (Denmark)

    Dam, Johan Hygum; Fristrup, Peter; Madsen, Robert

    2008-01-01

    -determining step. For Zn, In, Sn, Sb, and Bi, an inverse secondary kinetic isotope effect was found (k(H)/k(D) = 0.75-0.95), which was compatible with the formation of a discrete organometallic species prior to allylation via a closed six-membered transition state. With Mg, a significantly larger build...... with the effect of solvent described by a polarized continuum model. The calculated secondary deuterium isotope effects based on this mechanism were found to be in good agreement with experimental values, thus adding further support to this mechanistic scenario....

  9. Allyl Isothiocyanate Increases MRP1 Function and Expression in a Human Bronchial Epithelial Cell Line

    OpenAIRE

    Dian-lei Wang; Chen-yin Wang; Yin Cao; Xian Zhang; Xiu-hua Tao; Li-li Yang; Jin-pei Chen; Shan-shan Wang; Ze-geng Li

    2014-01-01

    Multidrug resistance-associated protein 1 (MRP1), a member of the ATP-binding cassette (ABC) superfamily of transporters, plays an important role in normal lung physiology by protecting cells against oxidative stress and toxic xenobiotics. The present study investigates the effects of allyl isothiocyanate (AITC) on MRP1 mRNA and MRP1 protein expression and transporter activity in the immortalised human bronchial epithelial cell line 16HBE14o-. MRP1 mRNA and MRP1 protein expression in 16HBE14o...

  10. Direct asymmetric allylic alkenylation of N-itaconimides with Morita-Baylis-Hillman carbonates

    KAUST Repository

    Yang, Wenguo

    2012-08-03

    The asymmetric allylic alkenylation of Morita-Baylis-Hillman (MBH) carbonates with N-itaconimides as nucleophiles has been developed using a commercially available Cinchona alkaloid catalyst. A variety of multifunctional chiral α-methylene-β-maleimide esters were attained in moderate to excellent yields (up to 99%) and good to excellent enantioselectivities (up to 91% ee). The origin of the regio- and stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed regio- and enantioselectivity. © 2012 American Chemical Society.

  11. Synthesis of Aryl Allyl Ether in the Recyclable Ionic Liquid [bmim]PF6

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Yun; Li Yi-Qun; Xu Xin-Ming

    2004-01-01

    Ionic liquids, especially imidazonium salts, have recently gained recognition as possible environmentally benign alternative chemical process solvents. This is mainly due to their nonvolatile nature, insolubility in some solvents as well as their ability to dissolve a wide range of organic and inorganic materials, allowing the ionic liquids easy recovery and recycling. Examples of their application in organic reactions have been summarized in a number of recent review articles.1Aryl allyl ether is very useful intermediate in organic synthesis. The Williamson reaction is a well knows method for the preparation ethers. However, the reaction of alkylating agents with the phenoxide ions was conventionally carried out in the organic solvents. The usual solvents for this type of reaction are DCM, 2 DMSO, 3 DMF, 4 CH3CN5 etc. With the current desire to avoid the use of organic molecular solvents in organic synthesis, we decide to investigate the use of the ionic liquid for the alternative solvent for the Williamson reaction to prepare the aryl allyl ethers. The ionic liquid employed here was the moisture stable 1-butyl-3-methylimidazolium hexafluorophosphate [bmim]PF6.6 The ionic liquid is non-volatile, thermally stable, and depending on the anion, can present low immiscible with water,alkanes and dialky ethers. We have now found that aryl allyl ethers can have been obtained from various phenols and allyl bromide in the presence of potassium hydroxide in [bmim]PF6 as a replacement for classical organic solvents in the ambient temperature. The results are shown in Scheme 1.The reaction were carried out by simple mixing the phenolwith the ally bromide and potassium hydroxide in [bmim]PF6 and stirred at room temperature for 4h. The results are summarized in Table 1.In conclusion, Williamson reaction can be successfully conducted in ionic liquid [bmim]PF6 with a number of advantages: the procedure is simple, the reaction condition is mild and the yields are excellent

  12. Antagonismo das associações de clodinafop-propargyl com metsulfuron-methyl e 2,4-D no controle de azevém (Lolium multiflorum Antagonistic action of clodinafop-propargyl associated with Metsulfuron-methyl and 2,4-D in the control of italian ryegrass (Lolium multiflorum

    Directory of Open Access Journals (Sweden)

    M.M. Trezzi

    2007-12-01

    Full Text Available Em geral, a eficiência de herbicidas inibidores da ACCase é reduzida quando da aplicação em conjunto com herbicidas latifolicidas. Dois experimentos - em casa de vegetação e campo - objetivaram determinar a existência de antagonismo nas associações de clodinafop-propargyl a metsulfuron-methyl ou 2,4-D, para controle de azevém anual. Em casa de vegetação, o delineamento foi o completamente casualizado, com 21 tratamentos compostos pela aplicação de clodinafop (0, 3, 6, 12, 24, 48 e 96 g ha-1 isolado ou em mistura com metsulfuron-methyl (2 e 4 g ha-1 ou 2,4-D (470 g ha-1. Em campo, o delineamento foi de blocos casualizados, com 12 tratamentos, arranjados em fatorial 6 x 2, composto pelos níveis de clodinafop-propargyl (0, 3, 6, 12, 24, 48 e 96 g ha¹ isolado ou em mistura com metsulfuron-methyl (2 g ha-1. A avaliação visual de controle, em casa de vegetação, revelou I50 das misturas de clodinafop-propargyl + metsulfuron-methyl (2 e 4 g ha-1 ou clodinafop-propargyl + 2,4-D (470 g ha-1, respectivamente, 33, 84 e 151% superiores ao de clodinafop-propargyl isolado. Já para matéria verde de azevém, o I50 das misturas supracitadas foi, respectivamente, 119, 244 e 72% superior ao de clodinafop-propargyl isolado. Em campo, ocorreu redução da matéria verde de azevém com a elevação dos níveis de clodinafop-propargyl isolado, mas não houve variação da matéria verde com a elevação dos níveis de clodinafop-propargyl, em associação a metsulfuron-methyl. Os resultados evidenciam a existência de antagonismo entre clodinafop-propargyl e os herbicidas metsulfuron-methyl e 2,4-D. São feitas considerações sobre as possíveis vantagens da aplicação dos herbicidas em mais de uma operação de controle, em comparação à associação entre graminicidas e latifolicidas.The efficacy of ACCase inhibitors is usually reduced when tank-mixed with broad leaf herbicides. A greenhouse and a field experiments were carried out to

  13. Communication: A vibrational study of propargyl cation using the vacuum ultraviolet laser velocity-map imaging photoelectron method

    Energy Technology Data Exchange (ETDEWEB)

    Gao Hong; Lu Zhou; Yang Lei; Zhou Jingang; Ng, C. Y. [Department of Chemistry, University of California, Davis, California 95616 (United States)

    2012-10-28

    By employing the vacuum ultraviolet (VUV) laser velocity-map imaging photoelectron (VUV-VMI-PE) method, we have obtained a vibrationally resolved photoelectron spectrum of gaseous propargyl radical [C{sub 3}H{sub 3}(X{sup 2}B{sub 1})] in the energy range of 0-4600 cm{sup -1} above its ionization energy. The cold C{sub 3}H{sub 3} radicals were produced from a supersonically cooled radical beam source based on 193 nm ArF photodissociation of C{sub 3}H{sub 3}Cl. The VUV-VMI-PE spectrum of C{sub 3}H{sub 3} thus obtained reveals a Franck-Condon factor (FCF) pattern with a highly dominant origin band along with weak vibrational progressions associated with excitations of the C-C {nu}{sub 5}{sup +}(a{sub 1}) and C{identical_to}C {nu}{sub 3}{sup +}(a{sub 1}) symmetric stretching modes and the CCH {nu}{sub 7}{sup +}(b{sub 1}) out-of-plane bending mode of C{sub 3}H{sub 3}{sup +}(X{sup 1}A{sub 1}). The {nu}{sub 5}{sup +}(a{sub 1}) vibrational frequency of 1120 cm{sup -1} determined in the present study is lower than the value deduced from the recent Ar-tagged infrared photodissociation study by 102 cm{sup -1}, confirming the highly accurate vibrational frequency predictions obtained by the most recent state-of-the-art ab initio quantum calculations. The observation of the FCF disallowed {nu}{sub 7}{sup +}(b{sub 1}) mode is indicative of vibronic interactions. The discrepancy observed between the FCF pattern determined in the present study and that predicted by a recent high-level quantum theoretical investigation can be taken as evidence that the potential energy surfaces used in the latter theoretical study are in need of improvement in order to provide a reliable FCF prediction for the C{sub 3}H{sub 3}/C{sub 3}H{sub 3}{sup +} photoionization system.

  14. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas.

    Science.gov (United States)

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter

    2014-01-01

    The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

  15. Beads,Necklaces, Chains and Strings in Capping Carbonyl Clusters

    Directory of Open Access Journals (Sweden)

    Enos Masheija Kiremire

    2015-09-01

    Full Text Available The paper attempts to explain at length the close relationship between transition metal carbonyl clusters with main group clusters especially the boranes using the 14n and 4n rules. When the ‘shielding’ electrons are removed from a transition metal carbonyl cluster and becomes ‘naked’, it resembles a corresponding one in the main group elements. A an expanded table of osmium carbonyl clusters was constructed using the capping fragment Os(CO2(14n-2 and the fragment Os(CO3 (14n+0. The table reveals the fact that the known series such closo, nido and arachno are part and parcel of a wide range of series especially the capping series 14n+q, where q takes up negative multiple integers of two including 0 such as such = 0, -2,-4, -6, and so on. The linkage between capping series in transition metal carbonyl clusters has also been identified. Apart from the capping series generated in the table, there is another type of series where the skeletal cluster elements remained the same but the number of carbonyl ligands successively decreased. These types of series are referred to as stripping series. Mapping generating functions were also derived which produces any cluster formula or series required. Also the table shows that many clusters form utilizing some of its atoms as closo nucleus around which the larger ones are built and thus forming clusters within larger clusters. The table may be used to categorize a given cluster formula that falls within its range. Otherwise, using the 14n rule or 4n rule can be used for cluster classification. Furthermore, the table indicated that atoms, fragments and molecules can be classified into series. Through this approach of using series, Hoffmann’s important isolobal relationship of chemical species can splendidly be explained.Using the 14n rule and 4n rules creates a framework under which chemical species such as atoms, fragments, molecules and ions some of which may appear unrelated from main group

  16. From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction.

    Science.gov (United States)

    Ríos-Lombardía, Nicolás; Vidal, Cristian; Liardo, Elisa; Morís, Francisco; García-Álvarez, Joaquín; González-Sabín, Javier

    2016-07-18

    The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning. PMID:27258838

  17. Iodine-Catalyzed Decarboxylative Amidation of β,γ-Unsaturated Carboxylic Acids with Chloramine Salts Leading to Allylic Amides.

    Science.gov (United States)

    Kiyokawa, Kensuke; Kojima, Takumi; Hishikawa, Yusuke; Minakata, Satoshi

    2015-10-26

    The iodine-catalyzed decarboxylative amidation of β,γ-unsaturated carboxylic acids with chloramine salts is described. This method enables the regioselective synthesis of allylic amides from various types of β,γ-unsaturated carboxylic acids containing substituents at the α- and β-positions. In the reaction, N-iodo-N-chloroamides, generated by the reaction of a chloramine salt with I2 , function as a key active species. The reaction provides an attractive alternative to existing methods for the synthesis of useful secondary allylic amine derivatives. PMID:26493878

  18. [Chemical Characteristics and Sources of Atmospheric Carbonyls During the 2014 Beijing APEC].

    Science.gov (United States)

    He, Xiao-lang; Tan, Ji-hua; Guo, Song-jun; Ma, Yong-liang; He, Ke-bin

    2016-03-15

    Pollution characteristic and variation trend of atmospheric carbonyls were investigated in November during the 2014 Beijing APEC. Formaldehyde, acetaldehyde and acetone were the dominant carbonyls, accounting for 82.66% of total carbonyls, and especially, formaldehyde accounted for 40.12% of total carbonyls. Atmospheric concentrations of total carbonyls decreased by around 64.10% after the clean air policy was carried out during the Beijing APEC, and the variation trend of carbonyls showed a similar pattern to those of other pollutants like PM₂.₅ during the APEC. Strong correlations (R² of 0.67-0.98) were observed among formaldehyde, acetaldehyde, acetone and total carbonyls during and after the APEC, indicating that they had similar sources; however, poor correlations (R² of -0.11-0.42 and 0.16-0.94, respectively) were observed before the APEC, implying different emission sources for ambient carbonyls. The calculated ratios of C1/C2, C2/C3 and OC/EC indicated that both vehicles and coal emissions were responsible for atmospheric carbonyls before the APEC, and emissions from coal burning were the major contributor to atmospheric carbonyls during and after the APEC, especially after the APEC. PMID:27337869

  19. Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

    Institute of Scientific and Technical Information of China (English)

    Chuanjia JIANG; Pengyi ZHANG

    2012-01-01

    Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1 I.tg.m3, and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6gg.m-3, respectively. Average indoor concentrations of other carbonyls were below I 0 gg. m~3. Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbo- nyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become signifi- cant in the case of a large human occupancy.

  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. Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

    Directory of Open Access Journals (Sweden)

    David Porter

    2015-12-01

    Full Text Available Iron(II complexes of the tetradentate amines tris(2-pyridylmethylamine (TPA and N,N′-bis(2-pyridylmethyl-N,N′-dimethylethane-1,2-diamine (BPMEN are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with either FeTPA (1 mol % or FeBPMEN (10 mol % converts cyclohexene to the allylic hydroxylamine (tert-butyl cyclohex-2-en-1-yl(hydroxycarbamate in moderate yields. Spectroscopic studies and trapping experiments suggest the reaction proceeds via a nitroso–ene mechanism, with involvement of a free N-Boc-nitroso intermediate. Asymmetric induction is not observed using the chiral tetramine ligand (+-(2R,2′R-1,1′-bis(2-pyridylmethyl-2,2′-bipyrrolidine ((R,R′-PDP.

  2. Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

    Directory of Open Access Journals (Sweden)

    Alireza Shakoori

    2015-04-01

    Full Text Available Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2’-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol-3-one (65% and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72% heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H-dione heterocyclic system.

  3. Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

    Science.gov (United States)

    Shakoori, Alireza; Bremner, John B; Abdel-Hamid, Mohammed K; Willis, Anthony C; Haritakun, Rachada

    2015-01-01

    Summary Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2’-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H)-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H)-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol)-3-one (65%) and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72%) heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS)-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H)-dione heterocyclic system. PMID:25977722

  4. Polymerizations of beta-substituted allylic arsonium ylides with catalytic amounts of organoboron compounds

    International Nuclear Information System (INIS)

    My Ph.D. work consisted in the generalization and optimization of a new polymerization reaction involving allylic arsonium ylides and catalytic amounts of various boron compounds. Thus, various β-substituted allylic arsonium salts were produced according to synthetic strategies that depended on the nature of the functional group born by the salt. These salts were converted in situ to the corresponding arsonium ylides which were then treated with boron compounds to yield polymers. Our new method of polymerization afforded either non conjugated polyenes that are functionalized every three atoms of carbon, or statistic copolymers, depending on the nature of the group R born on the β position of the ylide. These new polymers cannot be synthesized by usual methods of polymerization. Initial molar ratios of reactants were found to give molar mass control of the synthesized polymers. This controlled polymerization allowed us to produce several bloc copolymers. All the polymers were characterized by NMR techniques, by size exclusion chromatography and, for some of them, by mass spectrometry. Investigation of their physicochemical properties will need additional experiments. (author)

  5. Frustrated Lewis pairs-assisted reduction of carbonyl compounds

    DEFF Research Database (Denmark)

    Marek, Ales; Pedersen, Martin Holst Friborg

    2015-01-01

    An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, absolute regioselectivity and the non-metallic character of the reagent, it provides an excellent too...... for H-1, H-2 as well as H-3 chemistry. It is a new strategy for the one-pot synthesis of aromatic alcohols selectively labeled with heavy isotopes of hydrogen. © 2015 Elsevier Ltd. All rights reserved....

  6. Zinc mediated domino elimination-alkylation of methyl 5-iodopentofuranosides

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Poulsen, Carina Storm; Madsen, Robert

    1999-01-01

    5-Iodopentofuranosides are converted with zinc and allyl/propargyl bromide into dienes/enynes which are further used in carbohydrate annulation reactions.......5-Iodopentofuranosides are converted with zinc and allyl/propargyl bromide into dienes/enynes which are further used in carbohydrate annulation reactions....

  7. Asymmetric allylic alkylation in combination with ring-closing metathesis for the preparation of chiral N-heterocycles

    NARCIS (Netherlands)

    Teichert, Johannes F.; Zhang, Suyan; Zijl, Anthoni W. van; Slaa, Jan Willem; Minnaard, Adriaan J.; Feringa, Bernard

    2010-01-01

    Asymmetric copper-catalyzed allylic substitution with methylmagnesium bromide is employed in combination with ring-closing olefin metathesis or ene-yne metathesis to achieve the synthesis of chiral, unsaturated nitrogen heterocycles. The resulting six- to eight-membered chiral heterocycles are acces

  8. The NBS Reaction: A Simple Explanation for the Predominance of Allylic Substitution over Olefin Addition by Bromine at Low Concentrations.

    Science.gov (United States)

    Wamser, Carl C.; Scott, Lawrence T.

    1985-01-01

    Examines mechanisms related to use of N-bromosuccinimide (NBS) for bromination at an allylic position. Also presents derived rate laws for three possible reactions of molecular bromine with an alkene: (1) free radical substitution; (2) free radical addition; and (3) electrophilic addition. (JN)

  9. Organoselenium-catalyzed, hydroxy-controlled regio- and stereoselective amination of terminal alkenes: efficient synthesis of 3-amino allylic alcohols.

    Science.gov (United States)

    Deng, Zhimin; Wei, Jialiang; Liao, Lihao; Huang, Haiyan; Zhao, Xiaodan

    2015-04-17

    An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination. PMID:25849818

  10. Aldehyde Selective Wacker Oxidations of Phthalimide Protected Allylic Amines : A New Catalytic Route to beta(3)-Amino Acids

    NARCIS (Netherlands)

    Weiner, Barbara; Baeza Garcia, Alejandro; Jerphagnon, Thomas; Feringa, Ben L.

    2009-01-01

    A new method for the synthesis of B-3-amino acids is presented. Phthalimide protected allylic amines are oxidized under Wacker conditions selectively to aldehydes using PdCl2 and CuCl or Pd(MeCN)(2)Cl(NO2) and CuCl2 as complementary catalyst systems. The aldehydes are produced in excellent yields an

  11. Thiol addition to protected allyl glycosides: an improved method for the preparation of spacer-arm glycosides

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Seeventer, P.B. van; Dorst, J.A.L.M. van; Siemerink, J.F.; Kamerling, J.P.

    1997-01-01

    A useful method for the preparation of differently functionalized sulfide spacer-arm glycosides is presented. Several protected allyl glycosides were variously elongated via a radical addition reaction with pentanethiol, methyl 3-mercaptopropionate, or 2-mercaptoethanol. The hydroxyl function of pro

  12. Synthesis of novel chiral phosphine-triazine ligand derived from α-phenylethylamine for Pd-catalyzed asymmetric allylic alkylation

    Institute of Scientific and Technical Information of China (English)

    Jia Di Huang; Xiang Ping Hu; Zhuo Zheng

    2008-01-01

    A novel chiral phosphine-triazine ligand was synthesized from chiral model reaction of Pd-catalyzed allylic alkylation of rac-l,3-diphenylprop-2-en-l-yl pivalate with dimethyl malonate, good enantioselectivity (90% e.e.) was obtained by using this ligand.

  13. Growth behavior prediction of fresh catfish fillet with Pseudomonas aeruginosa under stresses of allyl isothiocyanate, temperature and modified atmosphere

    Science.gov (United States)

    Pseudomonas aeruginosa, a common spoilage microorganism in fish, grows rapidly when temperature rises above 4 degree C. The combination of allyl isothiocyanate (AIT) and modified atmosphere (MA) was applied and proved to be effective to retard the growth of P. aeruginosa. The objective of this resea...

  14. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions

    Science.gov (United States)

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid (PLA) and chitosan were incorporated with AIT and coated on one side of the film. T...

  15. Direct two-photon excitation of Sm3+, Eu3+, Tb3+, Tb.DOTA-, and Tb.propargylDO3A in solution

    Science.gov (United States)

    Sørensen, Thomas Just; Blackburn, Octavia A.; Tropiano, Manuel; Faulkner, Stephen

    2012-07-01

    We have observed direct two-photon excitation of samarium, europium and terbium ions in solution upon near IR excitation using a tuneable pulsed light source, and have also studied two-photon processes in a pair of related terbium complexes, namely [Tb.DOTA]- and Tb.propargylDO3A. Direct two-photon excitation of lanthanides is observed in simple systems in the absence of sensitizing chromophores. Where even simple chromophores such as a triple bond are present in the complex, then single and two-photon excitation of chromophore excited states competes with direct two-photon excitation of the ions and is the dominant pathway for sensitizing formation of the lanthanide excited state.

  16. Analysis of dynamic protein carbonylation in rice embryo during germination through AP-SWATH.

    Science.gov (United States)

    Zhang, Hui; He, Dongli; Yu, Jianlan; Li, Ming; Damaris, Rebecca Njeri; Gupta, Ravi; Kim, Sun Tae; Yang, Pingfang

    2016-03-01

    Seed germination is an important aspect of the plant life cycle, during which, reactive oxygen species (ROS) accumulate. The accumulation of ROS results in an increase in protein oxidation of which carbonylation is the most canonical one. However, there is insufficient information concerning protein oxidation, especially carbonylation and its contribution to seed germination. In this study, biotin hydrazide labeled chromatography combined with sequential window acquisition of all theoretical fragment ion spectra (SWATH) method was used to analyze the dynamic pattern of protein carbonylation in rice embryos during germination. A total of 1872 unique proteins were quantified, among which 288 carbonylated peptides corresponding to 144 proteins were determined based on the filtering through mass shifts of modified amino acids. In addition, 66 carbonylated proteins were further analyzed based on their carbonylation intensity in four stages of germination. These identified carbonylated proteins were mainly involved in maintaining the levels of ROS, abscisic acid and seed reserves. Remarkably, a peroxiredoxin was found with 23 unique carbonylated peptides, and the expression of which was consistent with its increased activity. This study describes the dynamic pattern of carbonylated proteins during seed germination, and may help to further understand the biochemical mechanisms on this process. PMID:26801057

  17. The carbonyl oxide-aldehyde complex: a new intermediate of the ozonolysis reaction

    Science.gov (United States)

    Cremer, Dieter; Kraka, Elfi; McKee, M. L.; Radharkrishnan, T. P.

    1991-12-01

    MP4(SDQ)/6-31G (d,p) calculations suggest that the ozonolysis of alkenes in solution phase does not proceed via carbonyl oxide, but via a dipole complex between aldehyde and carbonyl oxide, which is 9 kcal/mol more stable than the separated molecules. The dipole complex is probably formed in the solvent cage upon decomposition of primary ozonide to aldehyde and carbonyl oxide. Rotation of either aldehyde or carbonyl oxide in the solvent cage leads to an antiparallel alignment of molecular dipole moments and dipole-dipole attraction.

  18. Does a hydrogen bonded complex with dual contacts show synergism? A matrix isolation infrared and ab-initio study of propargyl alcohol-water complex

    Science.gov (United States)

    Saini, Jyoti; Viswanathan, K. S.

    2016-08-01

    When hydrogen bonded complexes are formed with more than one contact, the question arises if these multiple contacts operate synergistically. Propargyl alcohol-H2O complex presents a good case study to address this question, which is discussed in this work. Complexes of propargyl alcohol (PA) and H2O were studied experimentally using matrix isolation infrared spectroscopy, which was supported by quantum chemical computations performed at the M06-2X and MP2 level of theories, using 6-311++G (d,p) and aug-cc-pVDZ basis sets. A 1:1 PA-H2O complex was identified in the experiments and corroborated by our computations, where the PA was in the gauche conformation. This complex, which was a global minimum, showed dual interactions, one of which was an n-σ interaction between the O-H group of PA and the O of H2O, while the second was a H···​π contact between the O-H group of H2O and the π system of PA. We explored if the two interactions in the 1:1 complex exhibited synergism. We finally argue that the two interactions showed antagonism rather than synergism. Our computations indicated three other local minima for the 1:1 complexes; though these local minima were not identified in our experiments. Atoms-in-molecules and energy decomposition analysis executed through LMO-EDA were also performed to understand the nature of intermolecular interactions in the PA-H2O complexes. We have also revisited the problem of conformations of PA, with a view to understanding the reasons for gauche conformational preferences in PA.

  19. trans-Di-μ-carbonyl-bis{carbonyl[η5-2,3,4,5-tetramethyl-1-(5-methyl-2-furylcyclopentadienyl]ruthenium(I}(Ru—Ru

    Directory of Open Access Journals (Sweden)

    Jin Lin

    2009-08-01

    Full Text Available In the crystal structure of the title compound, [Ru2(C14H17O2(CO4], each RuI atom is connected to one end-on and two bridging carbonyl groups and one cyclopentadienyl ring. The two Ru atoms are connected into binuclear complexes via two bridging carbonyl groups, forming four-membered rings which are located on centres of inversion. The Ru—Ru distance of 2.7483 (11 Å corresponds to a single bond. The two carbonyl groups in these binuclear complexes are trans-oriented.

  20. Reactivity of Ir(III) carbonyl complexes with water: alternative by-product formation pathways in catalytic methanol carbonylation

    OpenAIRE

    Haynes, A.; Elliott, P. I. P.; Haak, S; Meijer, A.J.H.M.; Sunley, G.J

    2013-01-01

    The reactions of water with a number of iridium(III) complexes relevant to the mechanism for catalytic methanol carbonylation are reported. The iridium acetyl, [Ir(CO)2I3(COMe)]−, reacts with water under mild conditions to release CO2 and CH4, rather than the expected acetic acid. Isotopic labeling and kinetic experiments are consistent with a mechanism involving nucleophilic attack by water on a terminal CO ligand of [Ir(CO)2I3(COMe)]− to give an (undetected) hydroxycarbonyl spec...

  1. IRC analysis of methanol carbonylation reaction catalyzed by rhodium complex

    Institute of Scientific and Technical Information of China (English)

    HAO; Maorong; FENG; Wenlin; JI; Yongqiang; LEI; Ming

    2004-01-01

    In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2DZ level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and trans- structure exchange linkage of catalysis reactive species, the two pathways, cis- and trans-cata- lyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither cis-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.

  2. A step-by-step protocol for assaying protein carbonylation in biological samples.

    Science.gov (United States)

    Colombo, Graziano; Clerici, Marco; Garavaglia, Maria Elisa; Giustarini, Daniela; Rossi, Ranieri; Milzani, Aldo; Dalle-Donne, Isabella

    2016-04-15

    Protein carbonylation represents the most frequent and usually irreversible oxidative modification affecting proteins. This modification is chemically stable and this feature is particularly important for storage and detection of carbonylated proteins. Many biochemical and analytical methods have been developed during the last thirty years to assay protein carbonylation. The most successful method consists on protein carbonyl (PCO) derivatization with 2,4-dinitrophenylhydrazine (DNPH) and consequent spectrophotometric assay. This assay allows a global quantification of PCO content due to the ability of DNPH to react with carbonyl giving rise to an adduct able to absorb at 366 nm. Similar approaches were also developed employing chromatographic separation, in particular HPLC, and parallel detection of absorbing adducts. Subsequently, immunological techniques, such as Western immunoblot or ELISA, have been developed leading to an increase of sensitivity in protein carbonylation detection. Currently, they are widely employed to evaluate change in total protein carbonylation and eventually to highlight the specific proteins undergoing selective oxidation. In the last decade, many mass spectrometry (MS) approaches have been developed for the identification of the carbonylated proteins and the relative amino acid residues modified to carbonyl derivatives. Although these MS methods are much more focused and detailed due to their ability to identify the amino acid residues undergoing carbonylation, they still require too expensive equipments and, therefore, are limited in distribution. In this protocol paper, we summarise and comment on the most diffuse protocols that a standard laboratory can employ to assess protein carbonylation; in particular, we describe step-by-step the different protocols, adding suggestions coming from our on-bench experience.

  3. Influences of characteristic meteorological conditions on atmospheric carbonyls in Beijing, China

    Science.gov (United States)

    Pang, Xiaobing; Mu, Yujing; Lee, Xinqing; Zhang, Yujie; Xu, Zhu

    2009-08-01

    Atmospheric pollutants are controlled not only by their production rates but also by meteorological conditions. The influences of dust storm, sauna weather (haze with high temperature and high humidity), wet precipitation and wind speed on atmospheric carbonyls in Beijing were investigated. During a severe dust episode (April 17, 2006), the mixing ratios of carbonyls were significantly elevated to 13-27 ppbV from 7 to 13 ppbV in the previous non-dust days (April 15 and 16) with the increasing extents of 38-154%. The accumulating effect and the lower photolysis rate in the dust day may be responsible for the increases of carbonyls' levels. Additionally, the contribution from heterogeneous reactions occurring on dust particles to formaldehyde and acetaldehyde cannot be ruled out. During the period of typical sauna weather, the concentrations of atmospheric carbonyls increased to 18-60 ppbV from 10 to 17 ppbV before the sauna days. The air mass over Beijing during the sauna days was controlled by a subtropical anticyclone and the boundary layer became quite stable, which was beneficial to the rapid accumulation of air pollutants including carbonyls. Wet precipitation was found to be an effective removal process to the atmospheric carbonyls. After one-hour of rain in summer, the total concentrations of atmospheric carbonyls decreased to less than half of that before the rainfall. The similar temporal varying patterns of carbonyls and inorganic ions in rainwater indicated that carbonyls were mainly washed out from the atmosphere into rainwater as inorganic ions were. Strong wind could evidently dilute atmospheric carbonyls and a negative correlation was found between wind speeds and the concentrations of carbonyls in spring in Beijing.

  4. Enantioselective construction of quaternary N-heterocycles by palladium-catalysed decarboxylative allylic alkylation of lactams

    KAUST Repository

    Behenna, Douglas C.

    2011-12-18

    The enantioselective synthesis of nitrogen-containing heterocycles (N-heterocycles) represents a substantial chemical research effort and resonates across numerous disciplines, including the total synthesis of natural products and medicinal chemistry. In this Article, we describe the highly enantioselective palladium-catalysed decarboxylative allylic alkylation of readily available lactams to form 3,3-disubstituted pyrrolidinones, piperidinones, caprolactams and structurally related lactams. Given the prevalence of quaternary N-heterocycles in biologically active alkaloids and pharmaceutical agents, we envisage that our method will provide a synthetic entry into the de novo asymmetric synthesis of such structures. As an entry for these investigations we demonstrate how the described catalysis affords enantiopure quaternary lactams that intercept synthetic intermediates previously used in the synthesis of the Aspidosperma alkaloids quebrachamine and rhazinilam, but that were previously only available by chiral auxiliary approaches or as racemic mixtures. © 2012 Macmillan Publishers Limited. All rights reserved.

  5. Cutting thin sheets of allyl diglycol carbonate (CR-39) with a CW CO2, laser

    International Nuclear Information System (INIS)

    Recent studies have shown that Allyl Diglycol Carbonate, commercially known as CR-39 (the most sensitive among etch track detectors) can detect relativistic oxygen and other heavier nuclei. We are using large sheets of special grade CR-39 (DOP) in our experiment in Space Shuttle-Spacelab-3. As CR-39 is a highly brittle substance, special care is required to cut CR-39 shetts, especially in case of large sheets and circular cuts. A study of cutting of CR-39 sheets using laser light is described in this paper. It has been found that this method is sufficiently fast to handle large number of sheets and also equally safe for big sheets. A maximum speed up to 200 cm/min with a 5 x 104 W/cm2 laser is obtained during the present study. This study also shows that laser cutting does not affect the track properties of CR-39. (orig.)

  6. Theoretical study on the gas phase reaction of allyl chloride with hydroxyl radical.

    Science.gov (United States)

    Zhang, Yunju; Chao, Kai; Sun, Jingyu; Zhang, Wanqiao; Shi, Haijie; Yao, Cen; Su, Zhongmin; Pan, Xiumei; Zhang, Jingping; Wang, Rongshun

    2014-02-28

    The reaction of allyl chloride with the hydroxyl radical has been investigated on a sound theoretical basis. This is the first time to gain a conclusive insight into the reaction mechanism and kinetics for important pathways in detail. The reaction mechanism confirms that OH addition to the C=C double bond forms the chemically activated adducts, IM1 (CH2CHOHCH2Cl) and IM2 (CH2OHCHCH2Cl) via low barriers, and direct H-abstraction paths may also occur. Variational transition state model and multichannel RRKM theory are employed to calculate the temperature-, pressure-dependent rate constants. The calculated rate constants are in good agreement with the experimental data. At 100 Torr with He as bath gas, IM6 formed by collisional stabilization is the major products in the temperature range 200-600 K; the production of CH2CHCHCl via hydrogen abstractions becomes dominant at high temperatures (600-3000 K). PMID:24588171

  7. Theoretical study on the gas phase reaction of allyl chloride with hydroxyl radical

    Science.gov (United States)

    Zhang, Yunju; Chao, Kai; Sun, Jingyu; Zhang, Wanqiao; Shi, Haijie; Yao, Cen; Su, Zhongmin; Pan, Xiumei; Zhang, Jingping; Wang, Rongshun

    2014-02-01

    The reaction of allyl chloride with the hydroxyl radical has been investigated on a sound theoretical basis. This is the first time to gain a conclusive insight into the reaction mechanism and kinetics for important pathways in detail. The reaction mechanism confirms that OH addition to the C=C double bond forms the chemically activated adducts, IM1 (CH2CHOHCH2Cl) and IM2 (CH2OHCHCH2Cl) via low barriers, and direct H-abstraction paths may also occur. Variational transition state model and multichannel RRKM theory are employed to calculate the temperature-, pressure-dependent rate constants. The calculated rate constants are in good agreement with the experimental data. At 100 Torr with He as bath gas, IM6 formed by collisional stabilization is the major products in the temperature range 200-600 K; the production of CH2CHCHCl via hydrogen abstractions becomes dominant at high temperatures (600-3000 K).

  8. Low-temperature Electrodeposition of Aluminium from Lewis Acidic 1-Allyl-3-methylimidazolium Chloroaluminate Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    郑勇; 张锁江; 吕兴梅; 王倩; 左勇; 刘恋

    2012-01-01

    Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium. Systematic studies on deposition process have been performed by cYClic voltammetry and chronoamperometry. The surface morphology and X-ray diffraction (XRD) patterns of deposits prepared at different experimental conditions were also investigated. It was shown that the nucleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited. The crys- tallographic orientation of deposits was mainly influenced by temperature and current density. Smooth, dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA.cm^-2 and 313.2-353.2 K. More- over, the current efficiency of deposition and purity of aluminium have been significantly improved, demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.

  9. Iron(III)-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis.

    Science.gov (United States)

    Saá, Carlos

    2016-09-01

    Recent developments in catalytic carbonyl-olefin metathesis are summarized in this Highlight. Schindler and co-workers have reported that the environmentally benign FeCl3 catalyst promotes ring-closing carbonyl-olefin metathesis (RCCOM) in high yield under very mild conditions. PMID:27491787

  10. Iron(III)-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis.

    Science.gov (United States)

    Saá, Carlos

    2016-09-01

    Recent developments in catalytic carbonyl-olefin metathesis are summarized in this Highlight. Schindler and co-workers have reported that the environmentally benign FeCl3 catalyst promotes ring-closing carbonyl-olefin metathesis (RCCOM) in high yield under very mild conditions.

  11. Preparation and microwave shielding property of silver-coated carbonyl iron powder

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiao Guo, E-mail: xgcao@gdut.edu.cn [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong (China); Ren, Hao [Guangzhou Research Institute of O-M-E Technology, Guangzhou 510006, Guangdong (China); Zhang, Hai Yan [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong (China)

    2015-05-15

    Highlights: • The silver-coated carbonyl iron powder is prepared by the electroless plating process. • The silver-coated carbonyl iron powder is a new kind of conductive filler. • The reflection and absorption dominate the shielding mechanism of the prepared powder. • Increasing the thickness of electroconductive adhesive will increase the SE. - Abstract: Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range.

  12. Ketene as a Reaction Intermediate in the Carbonylation of Dimethyl Ether to Methyl Acetate over Mordenite

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Christensen, Jakob Munkholt; Temel, Burcin;

    2015-01-01

    Unprecedented insight into the carbonylation of dimethyl ether over Mordenite is provided through the identification of ketene (CH2CO) as a reaction intermediate. The formation of ketene is predicted by detailed DFT calculations and verified experimentally by the observation of doubly deuterated ...... acetic acid (CH2DCOOD), when D2O is introduced in the feed during the carbonylation reaction....

  13. Protein carbonylation after traumatic brain injury: cell specificity, regional susceptibility, and gender differences.

    Science.gov (United States)

    Lazarus, Rachel C; Buonora, John E; Jacobowitz, David M; Mueller, Gregory P

    2015-01-01

    Protein carbonylation is a well-documented and quantifiable consequence of oxidative stress in several neuropathologies, including multiple sclerosis, Alzheimer׳s disease, and Parkinson׳s disease. Although oxidative stress is a hallmark of traumatic brain injury (TBI), little work has explored the specific neural regions and cell types in which protein carbonylation occurs. Furthermore, the effect of gender on protein carbonylation after TBI has not been studied. The present investigation was designed to determine the regional and cell specificity of TBI-induced protein carbonylation and how this response to injury is affected by gender. Immunohistochemistry was used to visualize protein carbonylation in the brains of adult male and female Sprague-Dawley rats subjected to controlled cortical impact (CCI) as an injury model of TBI. Cell-specific markers were used to colocalize the presence of carbonylated proteins in specific cell types, including astrocytes, neurons, microglia, and oligodendrocytes. Results also indicated that the injury lesion site, ventral portion of the dorsal third ventricle, and ventricular lining above the median eminence showed dramatic increases in protein carbonylation after injury. Specifically, astrocytes and limited regions of ependymal cells adjacent to the dorsal third ventricle and the median eminence were most susceptible to postinjury protein carbonylation. However, these patterns of differential susceptibility to protein carbonylation were gender dependent, with males showing significantly greater protein carbonylation at sites distant from the lesion. Proteomic analyses were also conducted and determined that the proteins most affected by carbonylation in response to TBI include glial fibrillary acidic protein, dihydropyrimidase-related protein 2, fructose-bisphosphate aldolase C, and fructose-bisphosphate aldolase A. Many other proteins, however, were not carbonylated by CCI. These findings indicate that there is both regional

  14. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    Science.gov (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  15. Development of an automatic sampling device for the continuous measurement of atmospheric carbonyls compounds

    International Nuclear Information System (INIS)

    Two sampling strategies were studied to develop an automatic instrument for the continuous measurement of atmospheric carbonyl compounds. Because of its specificity towards carbonyls compounds, sampling by using a transfer of gaseous phase in a liquid phase associated with a simultaneous chemical derivatization of the trapped compounds was first studied. However, this method do not allow a quantitative sampling of all studied carbonyl compounds, nor a continuous measurement in the field. To overcome the difficulties, a second strategy was investigated: the cryogenic adsorption onto solid adsorbent followed by thermodesorption and a direct analysis by GC/MS. Collection efficiency using different solid adsorbents was found greater than 95% for carbonyl compounds consisting of 1 to 7 carbons. This work is a successful first step towards the realization of the automatic sampling device for a continuous measurement of atmospheric carbonyls compounds. (author)

  16. Expeditious Entry to Novel 2-Methylene-2,3-dihydrofuro[3,2-c] chromen-2-ones from 6-Chloro-4-hydroxychromen-2-one and Propargylic Alcohols

    Directory of Open Access Journals (Sweden)

    Josefina Díez

    2011-08-01

    Full Text Available A catalytic system consisting of the ruthenium(II complex [Ru(η3-2-C3H4Me(CO(dppf][SbF6] (dppf = 1,1’-bis(diphenylphosphinoferrocene and trifluoroacetic acid has been used to promote the coupling of secondary propargylic alcohols with 6-chloro-4-hydroxychromen-2-one. The reactions afforded unusual 2-methylene-2,3-dihydrofuro[3,2-c]chromen-2-ones in good yields.

  17. Synthesis, characterization and bioactivities of N,O-carbonylated chitosan.

    Science.gov (United States)

    Liu, Hongli; Liu, Xiaoli; Yue, Lin; Jiang, Qixing; Xia, Wenshui

    2016-10-01

    N,O-Carbonylated chitosan derivative (NTCS) was synthesized via oxidation and substitution reaction, respectively. The carboxyethylation of the polysaccharide was identified by Fourier transform infrared (FTIR), (1)H nuclear magnetic resonance (NMR), X-ray diffraction analysis (XRD), Zeta potential measurement and Thermogravimetric analysis (TGA). It is revealed that compared with chitosan (CS), NTCS exhibited an excellent solubility in distilled water, high in vitro bile acid binding capacity, as well as a low viscosity. The in vitro bile acid binding capacity reached 17.21mg/g, which was 4.5-fold higher than that of CS. The results suggest that NTCS may be useful as a potential functional food supplement in food industry or a key ingredient in the pharmaceutical industry. These findings provide important supports for developing new food additive, and expand the scope of application of CS in the food industry. PMID:27189702

  18. Carbonyl Sulfide Isotopologues: Ultraviolet Absorption Cross Sections and Stratospheric Photolysis

    DEFF Research Database (Denmark)

    Danielache, Sebastian Oscar; Nanbu, Shinkoh; Eskebjerg, Carsten;

    2009-01-01

    Ultraviolet absorption cross sections of the main and substituted carbonyl sulfide isotopologues were calculated using wavepacket dynamics. The calculated absorption cross section of 16O12C32S is in very good agreement with the accepted experimental spectrum between 190 and 250 nm. Relative to 16...... can be explained in terms of the change in the norm of the initial wavepacket. Implications for our understanding of the stratospheric sulfur cycle are discussed.......12C32S, isotopic substitution shows a significant enhancement of the cross section for 16O13C32S, a significant reduction for 18O12C32S and 17O12C32S and almost no change for the sulfur isotopologues 16O12C33S, 16O12C34S, and 16O12C36S. The analysis of the initial wavepackets shows that these changes...

  19. Formation of gold clusters on La-Ni mixed oxides and its catalytic performance for isomerization of allylic alcohols to saturated aldehydes

    International Nuclear Information System (INIS)

    Au/NiO catalyzed the isomerization of allylic alcohols to afford saturated aldehydes. La-Ni mixed oxide could stabilize Au(III) and afford gold clusters smaller than 1 nm by H2 reduction. The resulting Au clusters on La-Ni-O exhibited superior catalytic performance to Au/NiO for the isomerization of internal allylic alcohol, 2-octen-1-ol to octanal. (author)

  20. An Efficient Protocol for the Palladium-catalyzed Asymmetric Decarboxylative Allylic Alkylation Using Low Palladium Concentrations and a Palladium(II) Precatalyst

    OpenAIRE

    Marziale, Alexander N.; Duquette, Douglas C.; Craig, Robert A.; Kim, Kelly E.; Liniger, Marc; Numajiri, Yoshitaka; Stoltz, Brian M.

    2015-01-01

    Enantioselective catalytic allylic alkylation for the synthesis of 2-alkyl-2-allylcycloalkanones and 3,3-disubstituted pyrrolidinones, piperidinones and piperazinones has been previously reported by our laboratory. The efficient construction of chiral all-carbon quaternary centers by allylic alkylation was previously achieved with a catalyst derived in situ from zero valent palladium sources and chiral phosphinooxazoline (PHOX) ligands. We now report an improved reaction protocol with broad a...

  1. Direct Vapor Phase Carbonylation of Methanol over NiCl2/C Catalyst

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Introduction The carbonylation of alcohols via homogenous catalysis is important in manufacturing acetic acid and higher carboxylic acids and their esters[1,2]. The main route to produce acetic acid is to make methanol carbonylated by means of the Monsanto and BP process in which a homogeneous rhodium catalyst is used. Although the homogeneous carbonylation of methanol is a highly selective process, it is affected by the disadvantages associated with a highly corrosive reaction medium due to the use of methyl iodide as the promoter, and the difficulty of the product separation[3]. The use of a heterogeneous catalyst seems very interesting and attractive to us[4], especially the direct vapor phase carbonylation of methanol without a halide promoter is of considerable importance and is strong incentive economically. There has, however, been very little success in finding either heterogeneous or homogeneous catalysts that can catalyze the reaction effectively without the addition of a promoter[5,6]. According to the known carbonylation mechanism[7,8], the methyl iodide directly carbonylates with CO to from MeCOI which interacts with methanol(MeOH) to produce methyl acetate(MeCOOMe) and HI, and then MeOH reacts with HI to from CH3I. In fact, this carbonylation reaction is the indirect catalytic carbonylation of methanol[9]. In this work, a novel catalyst for the direct vapor phase carbonylation of methanol without the addition of any halide in the feed as a promoter was investigated. Compared to the known liquid phase methanol carbonylation process, some advantages of this vapor phase reaction are as follows:

  2. A chemical assessment of the suitability of allyl- iso-propyltelluride as a Te precursor for metal organic vapour phase epitaxy

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William; Foster, Douglas F.; Ellis, David

    2001-04-01

    The chemical studies, which led to the testing of allyl- iso-propyltelluride (allylTePr i) as a Te precursor in metal organic vapour phase epitaxy are presented. The pyrolysis in hydrogen of allylTePr i gave products including 1,5-hexadiene, propane and propene. Co-pyrolysis of dimethylcadmium (Me 2Cd) and allylTePr i gave the hydrocarbons expected from the pyrolysis of the individual precursors plus additional hydrocarbons including 2-methylpropane and 1-butene. Plots of percentage decomposition versus temperature, which proved extremely useful in determining the likely growth temperatures for both CdTe and HgTe, showed that allylTePr i is less stable than both Pr 2iTe (di- iso-propyltelluride) and Me 2Cd. The possible role of Hg in the growth of CdTe is also discussed. The chemistry of allylTePr i is well suited for use as an efficient precursor for epitaxial growth of tellurium containing semiconductors since there is very little formation of other organotellurium compounds on pyrolysis.

  3. One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters

    Science.gov (United States)

    Silveira-Dorta, Gastón; Álvarez-Méndez, Sergio J; Martín, Víctor S

    2016-01-01

    Summary An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction–olefination process. The sequential reduction with DIBAL-H at −78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives. PMID:27340486

  4. The pure rotational spectrum of a Claisen rearrangement precursor Allyl Phenyl Ether using CP-FTMW spectroscopy

    Science.gov (United States)

    Grubbs, G. S.; Frank, Derek S.; Obenchain, Daniel A.; Cooke, S. A.; Novick, Stewart E.

    2016-06-01

    The pure rotational spectrum of a Claisen rearrangement precursor, Allyl Phenyl Ether (APE), has been measured on a chirped pulse Fourier transform microwave (CP-FTMW) spectrometer in the 8-14 GHz region. Rotational and centrifugal distortion constants for multiple conformations have been determined and are reported for the first time. This is the first study of a phenyl-containing ether where multiple conformers were experimentally observed all within their ground vibrational states. Quantum chemical calculations have been performed to isolate low energy geometries of APE and are implemented to aid in spectral assignment. Other structural parameters such as planar moments and inertial defects for the Allyl Phenyl Ether conformers are presented and compared to similar molecules.

  5. REDUCING NONSELECTIVE PROTEIN ADSORPTION AND CELL ADHESION ON POLYACRYLONITRILE FILMS BY COPOLYMERIZATION OF ACRYLONITRILE WITH α-ALLYL GLUCOSIDE

    Institute of Scientific and Technical Information of China (English)

    Rui-qiang Kou; Chao Qu; Zhi-kang Xu; You-yi Xu; Ke Yao

    2003-01-01

    In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contact angle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorption amount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly with increasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both the hydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizing acrylonitrile with vinyl carbohydrates.

  6. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    OpenAIRE

    Julyana Ribeiro Garcia; Dalva Cristina Baptista do Lago; Fernando Lucas Gonçalves Silva; Eliane D'Elia; Aderval Severino Luna; Lilian Ferreira de Senna

    2013-01-01

    In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives) on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considere...

  7. Synchrotron Photoionization Mass Spectrometry Measurements of Kinetics and Product Formation in the Allyl Radical (H2CCHCH2)Self Reaction

    Science.gov (United States)

    Selby, Talitha M.; Melini, giovanni; Goulay, Fabien; Leone, Stephen R.; Fahr, Askar; Taatjes, Craig A.; Osborn, David L.

    2008-01-01

    Product channels for the self-reaction of the resonance-stabilized allyl radical, C3H5 + C3H5, have been studied with isomeric specificity at temperatures from 300-600 K and pressures from 1-6 Torr using time-resolved multiplexed photoionization mass spectrometry. Under these conditions 1,5-hexadiene was the only C6H10 product isomer detected. The lack of isomerization of the C6H10 product is in marked contrast to the C6H6 product in the related C3H3 + C3H3 reaction, and is due to the more saturated electronic structure of the C6H10 system. The disproportionation product channel, yielding allene + propene, was also detected, with an upper limit on the branching fraction relative to recombination of 0.03. Analysis of the allyl radical decay at 298 K yielded a total rate coefficient of (2.7 +/- 0.8) x 10(exp -11) cu cm/molecule/s, in good agreement with pre.vious experimental measurements using ultraviolet kinetic absorption spectroscopy and a recent theoretical determination using variable reaction coordinate transition state theory. This result provides independent indirect support for the literature value of the allyl radical ultraviolet absorption cross-section near 223 nm.

  8. Variation of ambient carbonyl levels in urban Beijing between 2005 and 2012

    Science.gov (United States)

    Chen, Wentai; Shao, Min; Wang, Ming; Lu, Sihua; Liu, Ying; Yuan, Bin; Yang, Yudong; Zeng, Limin; Chen, Zhongming; Chang, Chih-Chung; Zhang, Qian; Hu, Min

    2016-03-01

    Carbonyl compounds are important precursors of secondary air pollutants. With the rapid economic development and the implementation of stricter control measures in Beijing, the sources of carbonyls possibly changed. Based on measurement data obtained at an urban site in Beijing between 2005 and 2012, we investigated annual variations in carbonyl levels and sources during these years. In summer, formaldehyde and acetaldehyde levels decreased significantly at a rate of 9.1%/year and 7.2%/year, respectively, while acetone levels increased at a rate of 4.3%/year. In winter, formaldehyde levels increased and acetaldehyde levels decreased. We also investigated the factors driving the variation in carbonyls levels during summer by determination of emission ratios for carbonyls and their precursors, and calculation of photochemical formation of carbonyls. The relative declines for primary formaldehyde and acetaldehyde levels were larger than those for secondary formation. This is possibly due to the increasing usage of natural gas and liquefied petroleum gas which could result in the rise of carbonyl precursor emission ratios. The increase in acetone levels might be related to the rising solvent usage in Beijing during these years. The influences of these sources should be paid more attention in future research.

  9. Electroless plating preparation and electromagnetic properties of Co-coated carbonyl iron particles/polyimide composite

    Science.gov (United States)

    Zhou, Yingying; Zhou, Wancheng; Li, Rong; Qing, Yuchang; Luo, Fa; Zhu, Dongmei

    2016-03-01

    To solve the serious electromagnetic interference problems at elevated temperature, one thin microwave-absorbing sheet employing Co-coated carbonyl iron particles and polyimide was prepared. The Co-coated carbonyl iron particles were successfully prepared using an electroless plating method. The microstructure, composition, phase and static magnetic properties of Co-coated carbonyl iron particles were characterized by combination of scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The electromagnetic parameters of Co-coated carbonyl iron particles/polyimide composite were measured in the frequency range of 2-18 GHz, and the electromagnetic loss mechanism of the material-obtained was discussed. The microwave absorption properties of composites before and after heat treatment at 300 °C for 100 h were characterized in 2-18 GHz frequency range. It was established that composites based on Co-coated carbonyl iron demonstrate thermomagnetic stability, indicating that Co coating reduces the oxidation of carbonyl iron. Thus, Co-coated carbonyl iron particles/polyimide composites are useful in the design of microwave absorbers operating at temperatures up to 300 °C.

  10. FeCl3 -Catalyzed Ring-Closing Carbonyl-Olefin Metathesis.

    Science.gov (United States)

    Ma, Lina; Li, Wenjuan; Xi, Hui; Bai, Xiaohui; Ma, Enlu; Yan, Xiaoyu; Li, Zhiping

    2016-08-22

    Exploiting catalytic carbonyl-olefin metathesis is an ongoing challenge in organic synthesis. Reported herein is an FeCl3 -catalyzed ring-closing carbonyl-olefin metathesis. The protocol allows access to a range of carbo-/heterocyclic alkenes with good efficiency and excellent trans diastereoselectivity. The methodology presents one of the rare examples of catalytic ring-closing carbonyl-olefin metathesis. This process is proposed to take place by FeCl3 -catalyzed oxetane formation followed by retro-ring-opening to deliver metathesis products. PMID:27431372

  11. FeCl3 -Catalyzed Ring-Closing Carbonyl-Olefin Metathesis.

    Science.gov (United States)

    Ma, Lina; Li, Wenjuan; Xi, Hui; Bai, Xiaohui; Ma, Enlu; Yan, Xiaoyu; Li, Zhiping

    2016-08-22

    Exploiting catalytic carbonyl-olefin metathesis is an ongoing challenge in organic synthesis. Reported herein is an FeCl3 -catalyzed ring-closing carbonyl-olefin metathesis. The protocol allows access to a range of carbo-/heterocyclic alkenes with good efficiency and excellent trans diastereoselectivity. The methodology presents one of the rare examples of catalytic ring-closing carbonyl-olefin metathesis. This process is proposed to take place by FeCl3 -catalyzed oxetane formation followed by retro-ring-opening to deliver metathesis products.

  12. Visible Light-Induced Carbonylation Reactions with Organic Dyes as the Photosensitizers.

    Science.gov (United States)

    Peng, Jin-Bao; Qi, Xinxin; Wu, Xiao-Feng

    2016-09-01

    Dyes can CO do it: Organic dyes and pigments are usually applied in textile dyeing, which can be dated back to the Neolithic period. Interestingly, the possibility to use organic dyes as photoredox catalysts has also been noticed by organic chemists and applied in organic synthesis. Carbonylation reactions as a powerful procedure in carbonyl-containing compound preparation have also been studied. In this manuscript, the recent achievements in using organic dyes as visible-light sensitizers in carbonylation chemistry are summarized and discussed.

  13. 烯丙基酚醛树脂的固化动力学%Curing Kinetics of Allyl Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    刘洋; 刘诗薇; 李志强; 于景坤

    2012-01-01

    The curing behavior of allyl phenolic resin was analyzed at different heating rates using differential scanning calorimetry.The obtained kinetic data were treated by Kissinger and KAS(Kissinger-Akahira-Sunose) methods to obtain the curing reaction kinetic parameters.A curing kinetics model was established for allyl phenolic resin.Compared with phenolic resin,the curing temperature of allyl phenolic resin is higher,the reaction order is closer to 1,and the average activation energy of the curing reaction is lower,111.45 kJ/mol.The activation energy of allyl phenolic resin is almost constant and changes little with temperature in the curing process.The curing kinetics model of allyl phenolic resin provides a theoretical basis for the study of curing process parameters.%利用差示扫描量热法分析了烯丙基酚醛树脂在不同升温速率下的固化行为,用Kissinger法和KAS(Kissinger-Akahira-Sunose)法对获得的动力学数据进行处理,得到了固化反应动力学参数,并建立了烯丙基酚醛树脂的固化动力学模型.结果表明:与纯酚醛树脂相比,烯丙基酚醛树脂固化温度较高,反应级数更接近于1,固化反应所需的平均表观活化能较低,为111.45kJ/mol;在整个固化过程中,烯丙基酚醛树脂的活化能较为恒定,随温度变化不大;烯丙基酚醛树脂固化动力学模型为研究该体系固化工艺参数提供了理论依据.

  14. S-Propargyl-cysteine Exerts a Novel Protective Effect on Methionine and Choline Deficient Diet-Induced Fatty Liver via Akt/Nrf2/HO-1 Pathway

    Directory of Open Access Journals (Sweden)

    Wenwen Li

    2016-01-01

    Full Text Available This study investigated the antioxidative effect of S-propargyl-cysteine (SPRC on nonalcoholic fatty liver (NAFLD by treating mice fed a methionine and choline deficient (MCD diet with SPRC for four weeks. We found that SPRC significantly reduced hepatic reactive oxygen species (ROS and methane dicarboxylic aldehyde (MDA levels. Moreover, SPRC also increased the superoxide dismutase (SOD activity. By Western blot, we found that this protective effect of SPRC was importantly attributed to the regulated hepatic antioxidant-related proteins, including protein kinase B (Akt, heme oxygenase-1 (HO-1, nuclear factor erythroid 2-related factor 2 (Nrf2, and cystathionine γ-lyase (CSE, an enzyme that synthesizes hydrogen sulfide. Next, we examined the detailed molecular mechanism of the SPRC protective effect using oleic acid- (OA- induced HepG2 cells. The results showed that SPRC significantly decreased intracellular ROS and MDA levels in OA-induced HepG2 cells by upregulating the phosphorylation of Akt, the expression of HO-1 and CSE, and the translocation of Nrf2. SPRC-induced HO-1 expression and Nrf2 translocation were abolished by the phosphoinositide 3-kinase (PI3K inhibitor LY294002. Moreover, the antioxidative effect of SPRC was abolished by CSE inhibitor DL-propargylglycine (PAG and HO-1 siRNA. Therefore, these results proved that SPRC produced an antioxidative effect on NAFLD through the PI3K/Akt/Nrf2/HO-1 signaling pathway.

  15. S-Propargyl-Cysteine, a Novel Hydrogen Sulfide Donor, Inhibits Inflammatory Hepcidin and Relieves Anemia of Inflammation by Inhibiting IL-6/STAT3 Pathway

    Science.gov (United States)

    Xin, Hong; Zhu, Yi Zhun

    2016-01-01

    Anemia of inflammation (AI) is clinically prevalent and greatly threatens public health. Traditional remedies have raised controversy during clinical practice, calling for alternative therapies. We have recently found that hydrogen sulfide (H2S) inhibits inflammatory hepcidin, the critical mediator of AI. However, due to the chemical property of H2S, there remains an urgent need for a stable H2S donor in AI treatment. Here we reported that S-propargyl-cysteine (SPRC), a novel water-soluble H2S donor, suppressed hepatic hepcidin and corrected hypoferremia induced by lipopolysaccharide. The effects of SPRC were reversed by inhibition of cystathionine γ-lyase, one of the major endogenous H2S synthases. Moreover, SPRC reduced serum hepcidin, improved transferrin saturation, and maintained erythrocyte membrane integrity in a chronic mouse AI model. Consistently, splenomegaly was ameliorated and splenic iron accumulation relieved. Mechanism study indicated that serum IL-6 content and hepatic Il-6 mRNA were decreased by SPRC, in parallel with reduced hepatic JAK2/STAT3 activation. On the whole, our data reveal the inhibition of inflammatory hepcidin by SPRC, and suggest SPRC as a potential remedy against AI. PMID:27649298

  16. S-Propargyl-Cysteine, a Novel Hydrogen Sulfide Donor, Inhibits Inflammatory Hepcidin and Relieves Anemia of Inflammation by Inhibiting IL-6/STAT3 Pathway.

    Science.gov (United States)

    Wang, Minjun; Tang, Wenbo; Xin, Hong; Zhu, Yi Zhun

    2016-01-01

    Anemia of inflammation (AI) is clinically prevalent and greatly threatens public health. Traditional remedies have raised controversy during clinical practice, calling for alternative therapies. We have recently found that hydrogen sulfide (H2S) inhibits inflammatory hepcidin, the critical mediator of AI. However, due to the chemical property of H2S, there remains an urgent need for a stable H2S donor in AI treatment. Here we reported that S-propargyl-cysteine (SPRC), a novel water-soluble H2S donor, suppressed hepatic hepcidin and corrected hypoferremia induced by lipopolysaccharide. The effects of SPRC were reversed by inhibition of cystathionine γ-lyase, one of the major endogenous H2S synthases. Moreover, SPRC reduced serum hepcidin, improved transferrin saturation, and maintained erythrocyte membrane integrity in a chronic mouse AI model. Consistently, splenomegaly was ameliorated and splenic iron accumulation relieved. Mechanism study indicated that serum IL-6 content and hepatic Il-6 mRNA were decreased by SPRC, in parallel with reduced hepatic JAK2/STAT3 activation. On the whole, our data reveal the inhibition of inflammatory hepcidin by SPRC, and suggest SPRC as a potential remedy against AI. PMID:27649298

  17. 2-Alkynyl-N-propargyl pyridinium salts: pyridinium-based heterocyclic skipped aza-enediynes that cleave DNA by deoxyribosyl hydrogen-atom abstraction and guanine oxidation.

    Science.gov (United States)

    Tuesuwan, Bodin; Kerwin, Sean M

    2006-06-13

    Diradical-generating cyclizations such as the enediyne Bergman cyclization and the enyne allene Myers-Saito cyclization have been exploited by nature in the mechanism of DNA cleavage by a series of potent antitumor antibiotics. Alternative diradical-generating cyclizations have been proposed in the design of selective antitumor agents; however, little information is available concerning the utility of these alternative cyclizations in radical-based DNA cleavage chemistry. One such alternative diradical-generating cyclization, the aza-Myers-Saito cyclization of aza-enyne allenes that are derived from base-promoted isomerization of skipped aza-enediynes, has been recently reported. Here, we report the synthesis and DNA cleavage chemistry of a series of pyridinium skipped aza-enediynes (2-alkynyl-N-propargyl pyridinium salts). Efficient DNA cleavage requires the presence of the skipped aza-enediyne functionality, and optimal DNA cleavage occurs at basic pH. Within this series of compounds, the analogue bearing a p-methoxyphenyl group on the pyridinium 2-alkyne substituents was found to be the most effective DNA cleavage agent, displaying significant supercoiled DNA-nicking activity at concentrations as low as 1 microM. Detailed studies of this analogue show that DNA cleavage occurs through 4'-hydrogen-atom abstraction from the DNA backbone and oxidation of guanine bases. This is the first report of enediyne-like radical-based DNA cleavage by an agent designed to undergo an alternative diradical-generating cyclization. PMID:16752915

  18. Photocatalytic Degradation of Trifluralin, Clodinafop-Propargyl, and 1,2-Dichloro-4-Nitrobenzene As Determined by Gas Chromatography Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Niyaz A. Mir

    2014-01-01

    Full Text Available Phototransformation is considered one of the most key factors affecting the fate of pesticides. Therefore, our study focused on photocatalytic degradation of three selected pesticide derivatives: trifluralin (1, clodinafop-propargyl (2, and 1,2-dichloro-4-nitrobenzene (3. The degradation was carried out in acetonitrile/water medium in the presence of titanium dioxide (TiO2 under continuous purging of atmospheric air. The course of degradation was followed by thin-layer chromatography and gas chromatography-mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basis of molecular ion, mass fragmentation pattern, and comparison with NIST library. The photocatalytic degradation of pesticides of different chemical structures manifested distinctly different degradation mechanism. The major routes for the degradation of pesticides were found to be (a dealkylation, dehalogenation, and decarboxylation, (b hydroxylation, (c oxidation of side chain, if present, (d isomerization and cyclization, (e cleavage of alkoxy bond, and (f reduction of triple bond to double bond and nitro group to amino.

  19. Cyclodiphosphazanes as synthetic probes: P-C/P-N bond formation from the reaction with functionalized propargyl alcohols and -hydroxy substrates

    Indian Academy of Sciences (India)

    G Gangadhararao; K C Kumara Swamy

    2015-02-01

    Phosphano-indoles were synthesized in a fairly straightforward route from the reaction of simple cyclodiphosphazanes [XP(-N-t-Bu)2PY] [X=Y=NH--Bu (1a); X=Y=NH-i-Pr (1b)] with o-aminophenyl functionalized propargyl alcohols. The reaction occurs via an allene intermediate formed by PIII-O-C→PV(O)-C rearrangement, followed by cyclization utilizing the central allenic carbon and the –NH2 functionality. In a similar way, cyclodiphosphazanes [XP(-N-t-Bu)2PY] [X=Y=Cl (1c); X=Cl, Y=NH--Bu(1d)] have been treated with N-hydroxy substrates to obtain novel PIII-O-N→PV(O)-N rearranged products.X-ray structures of the four products, 2-(1-phenyl-ethyl)-3-[(t-Bu)NH)P(-N--Bu)2P(O)]-indole [14], cis-{[-C(=O)-C6H4-C(=O)-]-N-P(=O)-N-t-Bu}2[cis-18], trans-{[-C(=O)-C6H4-C(=O)-]-N-P(=O)-N--Bu}2 [trans-18] and cis-[(-BuNH)P(-N-t−Bu)2P(=O)-N{-C(=O)-CH2-CH2-C(=O)-}] [cis-19] are also reported

  20. Click synthesis of neutral, cationic, and zwitterionic poly(propargyl glycolide)-co-poly(ɛ-caprolactone)-based aliphatic polyesters as antifouling biomaterials.

    Science.gov (United States)

    Tu, Qin; Wang, Jian-Chun; Liu, Rui; Chen, Yun; Zhang, Yanrong; Wang, Dong-En; Yuan, Mao-Sen; Xu, Juan; Wang, Jinyi

    2013-08-01

    With the development of polymer-based biomaterials, aliphatic polyesters have attracted considerable interest because of their non-toxicity, non-allergenic property, and good biocompatibility. However, the hydrophobic nature and the lack of side chain functionalities of aliphatic polyesters limit their biomedical applications. In this study, we prepared four new polyesters: poly(sulfobetaine methacrylate)-, poly(2-methacryloyloxyethyl phosphotidylcholine)-, poly(ethylene glycol)-, and quaternized poly[(2-dimethylamino)ethyl methacrylate]-grafted poly(propargyl glycolide)-co-poly(ɛ-caprolactone). Their synthesis was conducted through ring-opening polymerization of acetylene-functionalized lactones and subsequent graft of bioactive units using click chemistry. The chemical structures of the polyesters were characterized through nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. For studies on their hydrophilicity, stability, and anti-bioadhesive property, a series of polymeric surfaces of these polyesters was prepared by coating them onto glass substrates. The hydrophilicity and stability of these polyester surfaces were examined by contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy. Their anti-bioadhesive property was investigated through protein adsorption, as well as cellular and bacterial adhesion assays. The prepared polyesters showed good hydrophilicity and long-lasting stability, as well as significant anti-fouling property. The newly prepared polyesters could be developed as promising anti-fouling materials with extensive biomedical applications. PMID:23511626

  1. Charged Propargyl-Linked Antifolates Reveal Mechanisms of Antifolate Resistance and Inhibit Trimethoprim-Resistant MRSA Strains Possessing Clinically Relevant Mutations.

    Science.gov (United States)

    Reeve, Stephanie M; Scocchera, Eric; Ferreira, Jacob J; G-Dayanandan, Narendran; Keshipeddy, Santosh; Wright, Dennis L; Anderson, Amy C

    2016-07-14

    Drug-resistant enzymes must balance catalytic function with inhibitor destabilization to provide a fitness advantage. This sensitive balance, often involving very subtle structural changes, must be achieved through a selection process involving a minimal number of eligible point mutations. As part of a program to design propargyl-linked antifolates (PLAs) against trimethoprim-resistant dihydrofolate reductase (DHFR) from Staphylococcus aureus, we have conducted a thorough study of several clinically observed chromosomal mutations in the enzyme at the cellular, biochemical, and structural levels. Through this work, we have identified a promising lead series that displays significantly greater activity against these mutant enzymes and strains than TMP. The best inhibitors have enzyme inhibition and MIC values near or below that of trimethoprim against wild-type S. aureus. Moreover, these studies employ a series of crystal structures of several mutant enzymes bound to the same inhibitor; analysis of the structures reveals a more detailed molecular understanding of drug resistance in this important enzyme. PMID:27308944

  2. Increased presevation of sliced mozzarella cheese by antimibrobial sachet incorporated with allyl isothiocyanate

    Directory of Open Access Journals (Sweden)

    Ana Clarissa dos Santos Pires

    2009-12-01

    Full Text Available There is an increasing tendency to add natural antimicrobials of plant origin into food. The objective of this work was to develop a microbial sachet incorporated with allyl isothiocyanate (AIT, a volatile compound of plant origin, and to test its efficiency against growth of yeasts and molds, Staphylococcus sp. and psychrotrophic bacteria on sliced mozzarella cheese. Another objective was to quantify the concentration of AIT in the headspace of cheese packaging. A reduction of 3.6 log cycles was observed in yeasts and molds counts in the mozzarella packed with the antimicrobial sachet over 15-day storage time. The sachet also showed an antibacterial effect on Staphylococcus sp., reducing 2.4 log cycles after 12-day storage. Psychrotrophic bacteria species were the most resistant to the antimicrobial action. The highest concentration of AIT (0.08µg.mL-1 inside the active packaging system was observed at the 6-day of storage at 12 ºC ± 2 ºC. At the end of the storage time, AIT concentration decreased to only 10% of the initial concentration. Active packaging containing antimicrobial sachet has a potential use for sliced mozzarella, with molds and yeasts being the most sensitive to the antimicrobial effects.

  3. Merging allylic carbon-hydrogen and selective carbon-carbon bond activation

    Science.gov (United States)

    Masarwa, Ahmad; Didier, Dorian; Zabrodski, Tamar; Schinkel, Marvin; Ackermann, Lutz; Marek, Ilan

    2014-01-01

    Since the nineteenth century, many synthetic organic chemists have focused on developing new strategies to regio-, diastereo- and enantioselectively build carbon-carbon and carbon-heteroatom bonds in a predictable and efficient manner. Ideal syntheses should use the least number of synthetic steps, with few or no functional group transformations and by-products, and maximum atom efficiency. One potentially attractive method for the synthesis of molecular skeletons that are difficult to prepare would be through the selective activation of C-H and C-C bonds, instead of the conventional construction of new C-C bonds. Here we present an approach that exploits the multifold reactivity of easily accessible substrates with a single organometallic species to furnish complex molecular scaffolds through the merging of otherwise difficult transformations: allylic C-H and selective C-C bond activations. The resulting bifunctional nucleophilic species, all of which have an all-carbon quaternary stereogenic centre, can then be selectively derivatized by the addition of two different electrophiles to obtain more complex molecular architecture from these easily available starting materials.

  4. Computational study of dissociative electron attachment to π-allyl ruthenium (II) tricarbonyl bromide

    Science.gov (United States)

    Thorman, Rachel M.; Bjornsson, Ragnar; Ingólfsson, Oddur

    2016-08-01

    Motivated by the current interest in low energy electron induced fragmentation of organometallic complexes in focused electron beam induced deposition (FEBID) we have evaluated different theoretical protocols for the calculation of thermochemical threshold energies for DEA to the organometallic complex π-allyl ruthenium (II) tricarbonyl bromide. Several different computational methods including density functional theory (DFT), hybrid-DFT and coupled cluster were evaluated for their ability to predict these threshold energies and compared with the respective experimental values. Density functional theory and hybrid DFT methods were surprisingly found to have poor reliability in the modelling of several DEA reactions; however, the coupled cluster method LPNO-pCCSD/2a was found to produce much more accurate results. Using the local correlation pair natural orbital (LPNO) methodology, high level coupled cluster calculations for open-shell systems of this size are now affordable, paving the way for reliable theoretical DEA predictions of such compounds. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  5. Allylic amination reactivity of Ni, Pd, and Pt heterobimetallic and monometallic complexes.

    Science.gov (United States)

    Carlsen, Ryan W; Ess, Daniel H

    2016-06-14

    Transition metal heterobimetallic complexes with dative metal-metal interactions have the potential for novel fast reactivity. There are few studies that both compare the reactivity of different metal centers in heterobimetallic complexes and compare bimetallic reactivity to monometallic reactivity. Here we report density-functional calculations that show the reactivity of [Cl2Ti(N(t)BuPPh2)2M(II)(η(3)-methallyl)] heterobimetallic complexes for allylic amination follows M = Ni > Pd > Pt. This reactivity trend was not anticipated since the amine addition transition state involves M(II) to M(0) reduction and this could disadvantage Ni. Comparison of heterobimetallic complexes to the corresponding monometallic (CH2)2(N(t)BuPPh2)2M(II)(η(3)-methallyl) complexes reveals that this reactivity trend is due to the bimetallic interaction and that the bimetallic interaction significantly lowers the barrier height for amine addition by >10 kcal mol(-1). The impact of the early transition metal center on the amination addition barrier height depends on the late transition metal center. The lowest barrier heights for this reaction occur when late and early transition metal centers are from the same periodic table row. PMID:26893287

  6. Allyl m-Trifluoromethyldiazirine Mephobarbital: An Unusually Potent Enantioselective and Photoreactive Barbiturate General Anesthetic

    Energy Technology Data Exchange (ETDEWEB)

    Savechenkov, Pavel Y.; Zhang, Xi; Chiara, David C.; Stewart, Deirdre S.; Ge, Rile; Zhou, Xiaojuan; Raines, Douglas E.; Cohen, Jonathan B.; Forman, Stuart A.; Miller, Keith W.; Bruzik, Karol S. (Harvard-Med); (Mass. Gen. Hosp.); (UIC)

    2012-12-10

    We synthesized 5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (14), a trifluoromethyldiazirine-containing derivative of general anesthetic mephobarbital, separated the racemic mixture into enantiomers by chiral chromatography, and determined the configuration of the (+)-enantiomer as S by X-ray crystallography. Additionally, we obtained the {sup 3}H-labeled ligand with high specific radioactivity. R-(-)-14 is an order of magnitude more potent than the most potent clinically used barbiturate, thiopental, and its general anesthetic EC{sub 50} approaches those for propofol and etomidate, whereas S-(+)-14 is 10-fold less potent. Furthermore, at concentrations close to its anesthetic potency, R-(-)-14 both potentiated GABA-induced currents and increased the affinity for the agonist muscimol in human {alpha}1{beta}2/3{gamma}2L GABA{sub A} receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both {alpha}1 and {beta}3 subunits of human {alpha}1{beta}3 GABAA receptors. These results indicate R-(-)-14 is a functional general anesthetic that is well-suited for identifying barbiturate binding sites on Cys-loop receptors.

  7. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Bjørnar Sporsheim

    2015-12-01

    Full Text Available Volatile allyl isothiocyanate (AITC derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER, vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

  8. Enhanced biocompatibility and wound healing properties of biodegradable polymer-modified allyl 2-cyanoacrylate tissue adhesive.

    Science.gov (United States)

    Lee, Young Ju; Son, Ho Sung; Jung, Gyeong Bok; Kim, Ji Hye; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2015-06-01

    As poly L-lactic acid (PLLA) is a polymer with good biocompatibility and biodegradability, we created a new tissue adhesive (TA), pre-polymerized allyl 2-cyanoacrylate (PACA) mixed with PLLA in an effort to improve biocompatibility and mechanical properties in healing dermal wound tissue. We determined optimal mixing ratios of PACA and PLLA based on their bond strengths and chemical structures analyzed by the thermal gravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. In vitro biocompatibility of the PACA/PLLA was evaluated using direct- and indirect-contact methods according to the ISO-10993 cytotoxicity test for medical devices. The PACA/PLLA have similar or even better biocompatibility than those of commercially available cyanoacrylate (CA)-based TAs such as Dermabond® and Histoacryl®. The PACA/PLLA were not different from those exposed to Dermabond® and Histoacryl® in Raman spectra when biochemical changes of protein and DNA/RNA underlying during cell death were compared utilizing Raman spectroscopy. Histological analysis revealed that incised dermal tissues of rats treated with PACA/PLLA showed less inflammatory signs and enhanced collagen formation compared to those treated with Dermabond® or Histoacryl®. Of note, tissues treated with PACA/PLLA were stronger in the tensile strength compared to those treated with the commercially available TAs. Therefore, taking all the results into consideration, the PACA/PLLA we created might be a clinically useful TA for treating dermal wounds. PMID:25842106

  9. Allyl Isothiocyanate Induces Cell Toxicity by Multiple Pathways in Human Breast Cancer Cells.

    Science.gov (United States)

    Bo, Peng; Lien, Jin-Cherng; Chen, Ya-Yin; Yu, Fu-Shun; Lu, Hsu-Feng; Yu, Chun-Shu; Chou, Yu-Cheng; Yu, Chien-Chih; Chung, Jing-Gung

    2016-01-01

    Isothiocyanates (ITCs) occur in many cruciferous vegetables. These compounds, which have significant anticancer actions, can induce apoptosis in different human cancer cell lines. In the present study, we investigated if allyl isothiocyanate (AITC) would induce toxicity in human breast cancer MCF-7 (estrogen receptor positive) and MDA-MB-231 (estrogen receptor negative) cells. We found that AITC stimulated reactive oxygen species and Ca[Formula: see text] production, and decreased the mitochondrial membrane potential. Activity of caspase-8, -9 and -3 was increased by AITC in both cell lines. AITC also induced mitochondrial-mediated apoptosis, as shown by cytochrome c, AIF and Endo G release from mitochondria, activation of caspase-9 and caspase-3, and formation of DAPI-positive cells. There was a significant reduction in the levels of the anti-apoptotic protein Bcl-2 along with a marked increase in the pro-apoptotic protein Bax in both cell lines. AITC induced apoptosis in human breast cancer MCF-7 cells via AIF and Endo G signaling pathways, but in MDA-MB-231 cells apoptosis occurred via the GADD153 pathway. This study has revealed novel anti-cancer mechanisms of AITC, a compound that is ordinarily present in human diets and may have potential therapeutic effects in various cancers. PMID:27080949

  10. Allyl isothiocyanates and cinnamaldehyde potentiate miniature excitatory postsynaptic inputs in the supraoptic nucleus in rats.

    Science.gov (United States)

    Yokoyama, Toru; Ohbuchi, Toyoaki; Saito, Takeshi; Sudo, Yuka; Fujihara, Hiroaki; Minami, Kouichiro; Nagatomo, Toshihisa; Uezono, Yasuhito; Ueta, Yoichi

    2011-03-25

    Allyl isothiocyanates (AITC) and cinnamaldehyde are pungent compounds present in mustard oil and cinnamon oil, respectively. These compounds are well known as transient receptor potential ankyrin 1 (TRPA1) agonists. TRPA1 is activated by low temperature stimuli, mechanosensation and pungent irritants such as AITC and cinnamaldehyde. TRPA1 is often co-expressed in TRPV1. Recent study showed that hypertonic solution activated TRPA1 as well as TRPV1. TRPV1 is involved in excitatory synaptic inputs to the magnocellular neurosecretory cells (MNCs) that produce vasopressin in the supraoptic nucleus (SON). However, it remains unclear whether TRPA1 may be involved in this activation. In the present study, we examined the role of TRPA1 on the synaptic inputs to the MNCs in in vitro rat brain slice preparations, using whole-cell patch-clamp recordings. In the presence of tetrodotoxin, AITC (50μM) and cinnamaldehyde (30μM) increased the frequency of miniature excitatory postsynaptic currents without affecting the amplitude. This effect was significantly attenuated by previous exposure to ruthenium red (10μM), non-specific TRP channels blocker, high concentration of menthol (300μM) and HC-030031 (10μM), which are known to antagonize the effects of TRPA1 agonists. These results suggest that TRPA1 may exist at presynaptic terminals to the MNCs and enhance glutamate release in the SON. PMID:21266172

  11. Allyl functionalized phosphinite and phosphonite ligands: Synthesis, transition metal chemistry and orthopalladation reactions

    Indian Academy of Sciences (India)

    Singappagudem Govindaraju; Guddekoppa S Ananthnag; Susmita Naik; Shaikh M Mobin; Maravanji S Balakrishn

    2012-07-01

    Allyl functionalized phosphinite PPh2(OAr) [Ar=C6H4(-C3H5)] (1) and phosphonite PPh(OAr)2 (2) ligands were prepared by the reactions of 2-allylphenol with PPh2Cl and PPhCl2, respectively. The ruthenium(II) complexes, [Ru(6--cymene)(PPh2(OAr))Cl2] (3) and [Ru(6--cymene)(PPh(OAr)2Cl2)] (4) were obtained by reacting 1 or 2 with [Ru(6--cymene)Cl2]2 in 2:1 molar ratios, respectively. Reactions of 1 or 2 with AuCl(SMe2) gave [Au{PPh2(OAr)}Cl] (5) or [Au{PPh(OAr)2}Cl] (6) in good yield. The palladium complex, [Pd{PPh(OAr)2}2Cl2] (7) was prepared by reacting Pd(COD)Cl2 with 2 in 1:2 molar ratio. The reaction between Pd(COD)Cl2 and 1 yielded a mixture of orthopalladated cis- and trans-[Pd(Ph2P(OAr))Cl]2 (8a and 8b). The treatment of 8 with PPh3 and Ph2PCH2PPh2 resulted in the cleavage of chloro bridge to give respectively, [Ph2(OAr)PPd(PPh3)Cl] (9) and [Ph2(ArO)PPd(2-dppm)]OTf (10). Single crystal X-ray structure of the ruthenium complex 3 is described.

  12. Human TTR conformation altered by rhenium tris-carbonyl derivatives.

    Science.gov (United States)

    Ciccone, Lidia; Policar, Clotilde; Stura, Enrico A; Shepard, William

    2016-09-01

    Transthyretin (TTR) is a 54 kDa homotetrameric serum protein that transports thyroxine (T4) and retinol. TTR is potentially amyloidogenic due to homotetramer dissociation into monomeric intermediates that self-assemble as amyloid deposits and insoluble fibrils. Most crystallographic structures, including those of amyloidogenic variants show the same tetramer without major variations in the monomer-monomer interface nor in the volume of the interdimeric cavity. Soaking TTR crystals in a solution containing rhenium tris-carbonyl derivatives yields a TTR conformer never observed before. Only one of the two monomers of the crystallographic dimer is significantly altered, and the inner part of the T4 binding cavity is expanded at one end and shrunk at the other. The result redefines the mechanism of allosteric communication between the two sites, suggesting that negative cooperativity is a function of dimer asymmetry, which can be induced through internal or external binding. An aspect that remains unexplained is why the conformational changes are ubiquitous throughout the crystal although the heavy metal content of the derivatized crystals is relatively low. The conformational changes observed, which include Leu(82), may represent a form of TTR better at scavenging β-Amyloid. At a resolution of 1.69Å, with excellent refinement statistics and well defined electron density for all parts of the structure, it is possible to envisage answering important questions that range from protein cooperative behavior to heavy atom induced protein conformational modifications that can result in crystallographic non-isomorphism. PMID:27402536

  13. The oceanic cycle and global atmospheric budget of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, P.S.

    1994-12-31

    A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

  14. Characterization of aura tropospheric emissions spectrometer carbonyl sulfide retrievals

    Directory of Open Access Journals (Sweden)

    L. Kuai

    2013-07-01

    Full Text Available We present a description of the Tropospheric Emission Spectrometer (TES carbonyl sulfide (OCS retrieval algorithm, along with evaluation of the biases and uncertainties against aircraft profiles from the HIPPO campaign and data from the NOAA Mauna Loa site. In general, the OCS retrievals (1 have less than 1.0 degree of freedom for signals (DOFs, (2 are sensitive in the mid-troposphere with a peak sensitivity typically between 300 to 500 hPa, (3 but have much smaller systematic errors from temperature, CO2 and H2O calibrations relative to random errors from measurement noise. Here we estimate the monthly means from TES measurements averaged over multiple years so that random errors are reduced and useful information about OCS seasonal and latitudinal variability can be derived. With this averaging, TES OCS data are found to be consistent (within the calculated uncertainties with NOAA ground observations and HIPPO aircraft measurements. TES OCS data also captures the seasonal and latitudinal variations observed by these in situ data.

  15. Aldol Condensation of Volatile Carbonyl Compounds in Acidic Aerosols

    Science.gov (United States)

    Noziere, B.; Esteve, W.

    2003-12-01

    Reactions of volatile organic compounds in acidic aerosols have been shown recently to be potentially important for organic aerosol formation and growth. Aldol condensation, the acid-catalyzed polymerization of carbonyl compounds, is a likely candidate to enhance the flux of organic matter from the gas phase to the condensed phase in the atmosphere. Until now these reactions have only been characterized for conditions relevant to synthesis (high acidities and liquid phase systems) and remote from atmospheric ones. In this work, the uptake of gas-phase acetone and 2,4\\-pentanedione by sulfuric acid solutions has been measured at room temperature using a Rotated Wetted Wall Reactor coupled to a Mass Spectrometer. The aldol condensation rate constants for 2,4\\-pentanedione measured so far for sulfuric acid solutions between 96 and 70 % wt. display a variation with acidity in agreement with what predicted in the organic chemical literature. The values of these constants, however, are much lower than expected for this compound, and comparable to the ones of acetone. Experiments are underway to complete this study to lower acidities and understand the discrepancies with the predicted reactivity.

  16. Heterogeneous oxidation of carbonyl sulfide on mineral oxides

    Institute of Scientific and Technical Information of China (English)

    LIU YongChun; LIU JunFeng; HE Hong; YU YunBo; XUE Li

    2007-01-01

    Heterogeneous oxidation of carbonyl sulfide (OCS) on mineral oxides including SiO2, Fe2O3, CaO, MgO, ZnO and TiO2, which are the main components of atmospheric particles, were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), ion chromatography (IC), temperature-programmed desorption (TPD), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods. The main products and intermediates of the heterogeneous oxidation of OCS on these oxides were identified with in situ DRIFTS and IC. The reaction mechanism and kinetics were also discussed. It is found that the reaction mechanism on these mineral oxides is the same as that on Al2O3 for the same final products and the intermediates at room temperature. Namely, OCS can be catalytically oxidized to produce surface SO42- species and gaseous CO2 through the surface hydrogen thiocarbonate (HSCO2-) and HSO3- species. The activity series for heterogeneous oxidation of OCS follows: Al2O3 ≈ CaO>MgO>TiO2 ≈ ZnO>Fe2O3>SiO2. The specific area, basic hydroxyl and surface basicity of these oxides have effect on the reactivity. This study suggests that heterogeneous reactions of OCS on mineral dust may be an unneglectable sink of OCS.

  17. Seasonal fluxes of carbonyl sulfide in a midlatitude forest

    Science.gov (United States)

    Commane, Róisín; Meredith, Laura K.; Baker, Ian T.; Berry, Joseph A.; Munger, J. William; Montzka, Stephen A.; Templer, Pamela H.; Juice, Stephanie M.; Zahniser, Mark S.; Wofsy, Steven C.

    2015-11-01

    Carbonyl sulfide (OCS), the most abundant sulfur gas in the atmosphere, has a summer minimum associated with uptake by vegetation and soils, closely correlated with CO2. We report the first direct measurements to our knowledge of the ecosystem flux of OCS throughout an annual cycle, at a mixed temperate forest. The forest took up OCS during most of the growing season with an overall uptake of 1.36 ± 0.01 mol OCS per ha (43.5 ± 0.5 g S per ha, 95% confidence intervals) for the year. Daytime fluxes accounted for 72% of total uptake. Both soils and incompletely closed stomata in the canopy contributed to nighttime fluxes. Unexpected net OCS emission occurred during the warmest weeks in summer. Many requirements necessary to use fluxes of OCS as a simple estimate of photosynthesis were not met because OCS fluxes did not have a constant relationship with photosynthesis throughout an entire day or over the entire year. However, OCS fluxes provide a direct measure of ecosystem-scale stomatal conductance and mesophyll function, without relying on measures of soil evaporation or leaf temperature, and reveal previously unseen heterogeneity of forest canopy processes. Observations of OCS flux provide powerful, independent means to test and refine land surface and carbon cycle models at the ecosystem scale.

  18. Teratogenicity and embryotoxicity of nickel carbonyl in Syrian hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, F.W. Jr.; Shen, S.K.; Reid, M.C.; Allpass, P.R.

    1980-01-01

    Nickel carbonyl was administered to groups of pregnant hamsters by inhalation on days 4, 5, 6, 7, or 8 of gestation. The dams were killed on day 15 of gestation, and the fetuses were examined for malformations. Exposure to Ni(CO)/sub 4/ on days 4 or 5 of gestation resulted in malformation in 5.5% and 5.8% of the progeny, respectively. Progeny included 9 fetuses with cystic lungs, 7 fetuses with exencephaly, 1 fetus with exencephaly plus fused rib and 1 fetus with anophthalmia plus cleft palate. Hemorrhages into serious cavities were found. In progeny of dams exposed to Ni(CO)/sub 4/ on days 6 or 7 of gestation, there was 1 fetus with fused ribs and there were 2 fetuses with hydronephrosis. In another experiment, pregnant hamsters were exposed to inhalation of Ni(CO)/sub 4/ on day 5 of gestation; these dams were permitted to deliver their litters and to nurse their pups. There was no significant difference in the average number of live pups in the Ni(CO)/sub 4/-exposed litters compared to control litters. Neonatal mortality was increased in Ni(CO)/sub 4/-exposed litters. This study demonstrates that Ni(CO)/sub 4/ is teratogenic and embryotoxic in Syrian hamsters.

  19. Atmospheric Sulfur Cycle Effects of Carbonyl Sulfide (OCS)

    Science.gov (United States)

    McBee, Joshua

    1996-01-01

    Carbonyl Sulfide(OCS) is considered to be one of the major sources of sulfur appearing in the stratosphere due to its relative inertness, about I to 10 yearsl. However, the roles of OCS as well as other reduced sulfur compounds such as carbon disulfide (CS2), hydrogen sulfide (H2S), and dimethyl disulfide(CH3)2S2, are not completely understood in the atmosphenc sulfur cycle. Consequently vely little information is available about the effect of sulfur compounds in the stratosphere. The ability of OCS to penetrate into the stratosphere makes it an excellent tracer for study of the role of the sulfi r cycle in stratospheric chemistry. Previously techniques such as gas chromatography and whole air sampling have been used to measure OCS analytically. Each technique had its drawbacks however, with both being quite slow, and whole air sampling being somewhat unreliable. With molecular spectroscopy, however, it has been found in recent years that the tunable diode laser absorption spectrometer (TDL) provides a very rapid and accurate method of measuring OCS and other trace gases

  20. Carbonyl Sulfide for Tracing Carbon Fluxes Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. Elliott [Univ. of California, Merced, CA (United States); Berry, Joseph A. [Carnegie Inst. of Science, Stanford, CA (United States); Billesbach, Dave [Univ. of Nebraska, Lincoln, NE (United States); Torn, Margaret S [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zahniser, Mark [Aerodyne Research, Inc., Billerica, MA (United States); Seibt, Ulrike [Univ. of California, Los Angeles, CA (United States); Maseyk, Kadmiel [Pierre and Marie Curie Univ., Paris (France)

    2016-04-01

    The April-June 2012 campaign was located at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) site Central Facility and had three purposes. One goal was to demonstrate the ability of current instrumentation to correctly measure fluxes of atmospheric carbonyl sulfide (COS). The approach has been describe previously as a critical approach to advancing carbon cycle science1,2, but requires further investigation at the canopy scale to resolve ecosystem processes. Previous canopy-scale efforts were limited to data rates of 1Hz. While 1 Hz measurements may work in a few ecosystems, it is widely accepted that data rates of 10 to 20 Hz are needed to fully capture the exchange of traces gases between the atmosphere and vegetative canopy. A second goal of this campaign was to determine if canopy observations could provide information to help interpret the seasonal double peak in airborne observations at SGP of CO2 and COS mixing ratios. A third goal was to detect potential sources and sinks of COS that must be resolved before using COS as a tracer of gross primary productivity (GPP).

  1. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  2. Synthesis of 2-Cyclopentenone Derivatives via Palladium-Catalyzed Intramolecular Carbonyl α-Alkenylation.

    Science.gov (United States)

    Chen, Panpan; Meng, Yinggao; Wang, Han; Han, Feipeng; Wang, Yulong; Song, Chuanjun; Chang, Junbiao

    2016-08-01

    2-Cyclopentenone derivatives have been efficiently synthesized from 5-bromo-5-hexen-2-ones via palladium-catalyzed intramolecular carbonyl α-alkenylation followed by double-bond migration under mild reaction conditions. PMID:27463262

  3. Nanostructured palladium tailored via carbonyl chemical route towards oxygen reduction reaction

    International Nuclear Information System (INIS)

    Graphical Abstract: Mass-depending morphologies of nanostructured Palladium obtained via the carbonyl chemical route. Display Omitted -- Highlights: •Mass-depending morphology was observed in nanostructured palladium supported on carbon prepared by the carbonyl chemical route. •The Morphological effect of carbon supported Pd was investigated towards ORR. -- Abstract: Carbon supported palladium nanostructures were synthesized via the carbonyl chemical route. Compared with nanostructured platinum, prepared via carbonyl chemical route, Pd nanomaterials showed mass-loading morphology, whereas particle size and morphology of Pt nanostructures was constant. The oxygen reduction reaction (ORR) on nanostructured Pd, with different morphology in both acid and alkaline medium was investigated. A relationship, based on X-ray diffraction structural analysis pattern, transmission electron microscope, with the Pd morphological effect on ORR activity was identified

  4. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu

    2014-02-07

    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  5. Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

    Science.gov (United States)

    Pierantozzi, Ronald

    1985-01-01

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  6. Incorporating Cobalt Carbonyl Moieties onto Ethynylthiophene-Based Dithienylcyclopentene Switches. 1. Photochemistry

    NARCIS (Netherlands)

    Harvey, Emma C.; Areephong, Jetsuda; Cafolla, Attilio A.; Long, Conor; Browne, Wesley R.; Pryce, Mary T.; Feringa, Bernard

    2014-01-01

    The synthesis and characterization of a series of dithienyl perhydro- and perfluorocyclopentene photochromic molecular switches appended with cobalt carbonyl binding 3-ethynylthiophene and phenyl-3-ethynylthiophene substituents are reported. Their photochromic properties, fatigue resistance, and the

  7. A carbonyl iron/carbon fiber material for electromagnetic wave absorption.

    Science.gov (United States)

    Youh, Meng-Jey; Wu, Hung-Chih; Lin, Wang-Hua; Chiu, Sheng-Cheng; Huang, Chien-Fa; Yu, Hsin-Chih; Hsu, Jen-Sung; Li, Yuan-Yao

    2011-03-01

    A carbonyl iron/carbon fiber material consisting of carbon fibers grown on micrometer-sized carbonyl iron sphere, was synthesized by chemical vapor deposition using a mixture of C2H2 and H2. The hollow-core carbon fibers (outer diameter: 140 nm and inner diameter: 40 nm) were composed of well-ordered graphene layers which were almost parallel to the long axis of the fibers. A composite (2 mm thick) consisting of the carbonyl iron/carbon fibers and epoxy resin demonstrated excellent electromagnetic (EM) wave absorption. Minimum reflection losses of -36 dB (99.95% of EM wave absorption) at 7.6 GHz and -32 dB (99.92% of EM wave absorption) at 34.1 GHz were achieved. The well-dispersed and network-like carbon fibers in the resin matrix affected the dielectric loss of the EM wave while the carbonyl iron affected the magnetic loss.

  8. Protein carbonylation and aggregation precede neuronal apoptosis induced by partial glutathione depletion

    Directory of Open Access Journals (Sweden)

    Jianzheng Zheng

    2012-04-01

    Full Text Available While the build-up of oxidized proteins within cells is believed to be toxic, there is currently no evidence linking protein carbonylation and cell death. In the present study, we show that incubation of nPC12 (neuron-like PC12 cells with 50 μM DEM (diethyl maleate leads to a partial and transient depletion of glutathione (GSH. Concomitant with GSH disappearance there is increased accumulation of PCOs (protein carbonyls and cell death (both by necrosis and apoptosis. Immunocytochemical studies also revealed a temporal/spatial relationship between carbonylation and cellular apoptosis. In addition, the extent of all three, PCO accumulation, protein aggregation and cell death, augments if oxidized proteins are not removed by proteasomal degradation. Furthermore, the effectiveness of the carbonyl scavengers hydralazine, histidine hydrazide and methoxylamine at preventing cell death identifies PCOs as the toxic species. Experiments using well-characterized apoptosis inhibitors place protein carbonylation downstream of the mitochondrial transition pore opening and upstream of caspase activation. While the study focused mostly on nPC12 cells, experiments in primary neuronal cultures yielded the same results. The findings are also not restricted to DEM-induced cell death, since a similar relationship between carbonylation and apoptosis was found in staurosporine- and buthionine sulfoximine-treated nPC12 cells. In sum, the above results show for the first time a causal relationship between carbonylation, protein aggregation and apoptosis of neurons undergoing oxidative damage. To the best of our knowledge, this is the first study to place direct (oxidative protein carbonylation within the apoptotic pathway.

  9. Fabrication and electromagnetic characteristics of microwave absorbers containing PPY and carbonyl iron composite

    Energy Technology Data Exchange (ETDEWEB)

    Li Dengao, E-mail: lidengao123@163.com [College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang Hongbin; Zhao Jumin [College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yang Xiaoli [Department of Electrical and Computer Engineering, Purdue University Calumet, IN 46323-2094 (United States)

    2011-10-17

    Highlights: {yields} Polypyrrole powders are prepared by in situ polymerization method. {yields} Then PPY-carbonyl iron composite with different mixture ratios have been prepared. {yields} The effect of the mass ratio of PPY-carbonyl iron on the microwave loss properties of the composites is investigated. {yields} A possible microwave absorbing mechanism of PPY-carbonyl iron composite has been proposed. - Abstract: The objective of this study is to develop microwave absorbers using both dielectric and magnetic lossy materials. Polypyrrole (PPY) is used as dielectric lossy materials and carbonyl iron particles is used as magnetic lossy materials. Polypyrrole powders are prepared by in situ polymerization method. Then PPY-carbonyl iron composite with different mixture ratios have been prepared by as-prepared material. The structure, morphology and properties of the composites are characterized with IR, XRD, scanning electron microscope (SEM), Net-work Anlyzer. The complex permittivity ({epsilon}{sup '}{sub r}-j{epsilon}{sup ''}{sub r}) and reflection loss (dB) of the composites have been measured at different microwave frequencies in S-band and C-band (30-6000 MHz) employing vector network analyzer model HP 8722ET vector. The effect of the mass ratio of PPY-carbonyl iron on the microwave loss properties of the composites is investigated. A possible microwave absorbing mechanism of PPY-carbonyl iron composite has been proposed. The PPY-carbonyl iron composite can find applications in suppression of electromagnetic interference (EMI), and reduction of radar signature.

  10. Proteomic analysis and protein carbonylation profile in trained and untrained rat muscle

    OpenAIRE

    F.Magherini; P.M. Abruzzo; Puglia, M.; Bini, L.; T. Gamberi; Esposito, F; A. Veicsteinas; Marini, M.; Fiorillo, C; Gulisano, M; Modesti, A

    2012-01-01

    Understanding the relationship between physical exercise, reactive oxygen species and skeletal muscle modification is important in order to better identify the benefits or the damages that appropriate or inappropriate exercise can induce. Unbalanced ROS levels can lead to oxidation of cellular macromolecules and a major class of protein oxidative modification is carbonylation. The aim of this investigation was to study muscle protein expression and carbonylation patterns in tra...

  11. COMPARATIVE STUDY OF EFFICACY OF FERROUS SULPHATE AND CARBONYL IRON IN ANEMIA OF ANTENATAL WOMEN

    Directory of Open Access Journals (Sweden)

    Radhika

    2015-03-01

    Full Text Available Iron deficiency anemia is the most common and important public health problem all over the world in the risk group of antenatal women. Research is going on to improve the iron status of the pregnant women with different forms of iron available. In this regard, Carbonyl Iron is showing promising results in improving the red cell mass with better compliance. 120 antenatal women were recruited in this study. The study comprised of 6weeks for each patient. They were given Carbonyl Iron 100 mg/day and FeS04 100gm/day . Before and after treatment all the baseline and specific investigations were one. Results were tabulated, comparison and significance were tested by unpaired student ’s’ test and their 'p' value was calculated. Results were shown graphically also. Carbonyl Iron showed improvement in hemoglobin, PCV and better than ferrous Sulphate (P <0.001. Incidence of side effects were less with Carbonyl Iron than Ferrous Sulphate, better compliance was seen with Carbonyl Iron. In conclusion, the present study s howed that Carbonyl Iron had better efficacy and safety in the management of Iron deficiency anemia in antenatal women than ferrous Sulphate

  12. Oxidative Stress and Carbonyl Lesions in Ulcerative Colitis and Associated Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Zhiqi Wang

    2016-01-01

    Full Text Available Oxidative stress has long been known as a pathogenic factor of ulcerative colitis (UC and colitis-associated colorectal cancer (CAC, but the effects of secondary carbonyl lesions receive less emphasis. In inflammatory conditions, reactive oxygen species (ROS, such as superoxide anion free radical (O2∙-, hydrogen peroxide (H2O2, and hydroxyl radical (HO∙, are produced at high levels and accumulated to cause oxidative stress (OS. In oxidative status, accumulated ROS can cause protein dysfunction and DNA damage, leading to gene mutations and cell death. Accumulated ROS could also act as chemical messengers to activate signaling pathways, such as NF-κB and p38 MAPK, to affect cell proliferation, differentiation, and apoptosis. More importantly, electrophilic carbonyl compounds produced by lipid peroxidation may function as secondary pathogenic factors, causing further protein and membrane lesions. This may in turn exaggerate oxidative stress, forming a vicious cycle. Electrophilic carbonyls could also cause DNA mutations and breaks, driving malignant progression of UC. The secondary lesions caused by carbonyl compounds may be exceptionally important in the case of host carbonyl defensive system deficit, such as aldo-keto reductase 1B10 deficiency. This review article updates the current understanding of oxidative stress and carbonyl lesions in the development and progression of UC and CAC.

  13. Allyl/propenyl phenol synthases from the creosote bush and engineering production of specialty/commodity chemicals, eugenol/isoeugenol, in Escherichia coli.

    Science.gov (United States)

    Kim, Sung-Jin; Vassão, Daniel G; Moinuddin, Syed G A; Bedgar, Diana L; Davin, Laurence B; Lewis, Norman G

    2014-01-01

    The creosote bush (Larrea tridentata) harbors members of the monolignol acyltransferase, allylphenol synthase, and propenylphenol synthase gene families, whose products together are able to catalyze distinct regiospecific conversions of various monolignols into their corresponding allyl- and propenyl-phenols, respectively. In this study, co-expression of a monolignol acyltransferase with either substrate versatile allylphenol or propenylphenol synthases in Escherichia coli established that various monolignol substrates were efficiently converted into their corresponding allyl/propenyl phenols, as well as providing proof of concept for efficacious conversion in a bacterial platform. This capability thus potentially provides an alternate source to these important plant phytochemicals, whether for flavor/fragrance and fine chemicals, or ultimately as commodities, e.g., for renewable energy or other intermediate chemical purposes. Previous reports had indicated that specific and highly conserved amino acid residues 84 (Phe or Val) and 87 (Ile or Tyr) of two highly homologous allyl/propenyl phenol synthases (circa 96% identity) from a Clarkia species mainly dictate their distinct regiospecific catalyzed conversions to afford either allyl- or propenyl-phenols, respectively. However, several other allyl/propenyl phenol synthase homologs isolated by us have established that the two corresponding amino acid 84 and 87 residues are not, in fact, conserved.

  14. Fluorinated alcohols as promoters for the metal-free direct substitution reaction of allylic alcohols with nitrogenated, silylated, and carbon nucleophiles.

    Science.gov (United States)

    Trillo, Paz; Baeza, Alejandro; Nájera, Carmen

    2012-09-01

    The direct allylic substitution reaction using allylic alcohols in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and 2,2,2-trifluoroethanol (TFE) as reaction media is described. The developed procedure is simple, works under mild conditions (rt, 50 and 70 °C), and proves to be very general, since different nitrogenated nucleophiles and carbon nucleophiles can be used achieving high yields, especially when HFIP is employed as solvent and aromatic allylic alcohols are the substrates. Thus, sulfonamides, carbamates, carboxamides, and amines can be successfully employed as nitrogen-based nucleophiles. Likewise, silylated nucleophiles such as trimethylsilylazide, allyltrimethylsilane, trimethylsilane, and trimethylsilylphenylacetylene give the corresponding allylic substitution products in high yields. Good results for the Friedel-Crafts adducts are also achieved with aromatic compounds (phenol, anisole, indole, and anilines) as nucleophiles. Particularly interesting are the results obtained with electron-rich anilines, which can behave as nitrogenated or carbon nucleophiles depending on their electronic properties and the solvent employed. In addition, 1,3-dicarbonyl compounds (acetylacetone and Meldrum's acid) are also successfully employed as soft carbon nucleophiles. Studies for mechanism elucidation are also reported, pointing toward the existence of carbocationic intermediates and two working reaction pathways for the obtention of the allylic substitution product.

  15. Protein carbonylation, protein aggregation and neuronal cell death in a murine model of multiple sclerosis

    Science.gov (United States)

    Dasgupta, Anushka

    Many studies have suggested that oxidative stress plays an important role in the pathophysiology of both multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Yet, the mechanism by which oxidative stress leads to tissue damage in these disorders is unclear. Recent work from our laboratory has revealed that protein carbonylation, a major oxidative modification caused by severe and/or chronic oxidative stress conditions, is elevated in MS and EAE. Furthermore, protein carbonylation has been shown to alter protein structure leading to misfolding/aggregation. These findings prompted me to hypothesize that carbonylated proteins, formed as a consequence of oxidative stress and/or decreased proteasomal activity, promote protein aggregation to mediate neuronal apoptosis in vitro and in EAE. To test this novel hypothesis, I first characterized protein carbonylation, protein aggregation and apoptosis along the spinal cord during the course of myelin-oligodendrocyte glycoprotein (MOG)35-55 peptide-induced EAE in C57BL/6 mice [Chapter 2]. The results show that carbonylated proteins accumulate throughout the course of the disease, albeit by different mechanisms: increased oxidative stress in acute EAE and decreased proteasomal activity in chronic EAE. I discovered not only that there is a temporal correlation between protein carbonylation and apoptosis but also that carbonyl levels are significantly higher in apoptotic cells. A high number of juxta-nuclear and cytoplasmic protein aggregates containing the majority of the oxidized proteins are also present during the course of EAE, which seems to be due to reduced autophagy. In chapter 3, I show that when gluthathione levels are reduced to those in EAE spinal cord, both neuron-like PC12 (nPC12) cells and primary neuronal cultures accumulate carbonylated proteins and undergo cell death (both by necrosis and apoptosis). Immunocytochemical and biochemical studies also revealed a temporal

  16. Intramolecular Hydrogen Bond in Biologically Active o-Carbonyl Hydroquinones

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes

    2014-07-01

    Full Text Available Intramolecular hydrogen bonds (IHBs play a central role in the molecular structure, chemical reactivity and interactions of biologically active molecules. Here, we study the IHBs of seven related o-carbonyl hydroquinones and one structurally-related aromatic lactone, some of which have shown anticancer and antioxidant activity. Experimental NMR data were correlated with theoretical calculations at the DFT and ab initio levels. Natural bond orbital (NBO and molecular electrostatic potential (MEP calculations were used to study the electronic characteristics of these IHB. As expected, our results show that NBO calculations are better than MEP to describe the strength of the IHBs. NBO energies (∆Eij(2 show that the main contributions to energy stabilization correspond to LPàσ* interactions for IHBs, O1…O2-H2 and the delocalization LPàπ* for O2-C2 = Cα(β. For the O1…O2-H2 interaction, the values of ∆Eij(2 can be attributed to the difference in the overlap ability between orbitals i and j (Fij, instead of the energy difference between them. The large energy for the LP O2àπ* C2 = Cα(β interaction in the compounds 9-Hydroxy-5-oxo-4,8, 8-trimethyl-l,9(8H-anthracenecarbolactone (VIII and 9,10-dihydroxy-4,4-dimethylanthracen-1(4H-one (VII (55.49 and 60.70 kcal/mol, respectively when compared with the remaining molecules (all less than 50 kcal/mol, suggests that the IHBs in VIII and VII are strongly resonance assisted.

  17. Metabolism of bupropion by carbonyl reductases in liver and intestine.

    Science.gov (United States)

    Connarn, Jamie N; Zhang, Xinyuan; Babiskin, Andrew; Sun, Duxin

    2015-07-01

    Bupropion's metabolism and the formation of hydroxybupropion in the liver by cytochrome P450 2B6 (CYP2B6) has been extensively studied; however, the metabolism and formation of erythro/threohydrobupropion in the liver and intestine by carbonyl reductases (CR) has not been well characterized. The purpose of this investigation was to compare the relative contribution of the two metabolism pathways of bupropion (by CYP2B6 and CR) in the subcellular fractions of liver and intestine and to identify the CRs responsible for erythro/threohydrobupropion formation in the liver and the intestine. The results showed that the liver microsome generated the highest amount of hydroxybupropion (Vmax = 131 pmol/min per milligram, Km = 87 μM). In addition, liver microsome and S9 fractions formed similar levels of threohydrobupropion by CR (Vmax = 98-99 pmol/min per milligram and Km = 186-265 μM). Interestingly, the liver has similar capability to form hydroxybupropion (by CYP2B6) and threohydrobupropion (by CR). In contrast, none of the intestinal fractions generate hydroxybupropion, suggesting that the intestine does not have CYP2B6 available for metabolism of bupropion. However, intestinal S9 fraction formed threohydrobupropion to the extent of 25% of the amount of threohydrobupropion formed by liver S9 fraction. Enzyme inhibition and Western blots identified that 11β-dehydrogenase isozyme 1 in the liver microsome fraction is mainly responsible for the formation of threohydrobupropion, and in the intestine AKR7 may be responsible for the same metabolite formation. These quantitative comparisons of bupropion metabolism by CR in the liver and intestine may provide new insight into its efficacy and side effects with respect to these metabolites.

  18. Soil fluxes of carbonyl sulfide (COS) across four distinct ecosystems

    Science.gov (United States)

    Sun, W.; Maseyk, K. S.; Lett, C.; Juarez, S.; Kooijmans, L.; Mammarella, I.; Vesala, T.; Chen, H.; Seibt, U.

    2015-12-01

    Soils are additional but poorly resolved sinks of carbonyl sulfide (COS) in terrestrial ecosystems. COS has been proposed as a tracer for quantifying gross photosynthesis based on the coupled stomatal uptake of COS and CO2. But applying this tracer requires the soil COS flux to be subtracted from the ecosystem flux to obtain the actual plant flux. To simulate soil COS fluxes, we have built a 1-D diffusion-reaction model accounting for vertical transport in the soil, microbial sinks and sources, and a litter layer. Uptake and production of COS in the soil column are linked with soil temperature and moisture through empirical functions adapted from enzyme kinetics and lab incubations. We have measured soil COS fluxes and the related soil variables in four distinct ecosystems: a wheat field (Southern Great Plains, OK, USA), an oak woodland (Santa Monica Mountains, CA, USA), a tropical rainforest (La Selva Biological Station, Costa Rica) and a boreal pine forest (Hyytiälä, Finland). Across all sites, a lower soil temperature and a humid climate are generally favorable to soil COS uptake. Strong COS emissions were observed in the wheat field at high soil temperatures after harvesting but were absent in other ecosystems, indicating that COS exchange may behave differently in agricultural soils. We simulated the soil fluxes in all ecosystems using the diffusion-reaction model, and optimized the source/sink strength parameters with field data. The optimized model provides insights that are not attainable from data analysis alone: For example, the wheat field soil must have continued uptake activity even when it showed net emissions, and leaf litter contributed dominantly to the COS sink after rain in the oak woodland. We expect the new model to be useful for simulating global soil COS fluxes as field data on soil fluxes from a broader range of ecosystems become available.

  19. Organometallic and Bioorganometallic Chemistry - Ferrocene and Metal Carbonyls

    Directory of Open Access Journals (Sweden)

    Čakić Semenčić, M.

    2011-02-01

    Full Text Available Organometallic chemistry deals with compounds containing metal-carbon bonds. Basic organometallics derived from the s- and p-block metals (containing solely σ-bonds were understood earlier, while organometallic chemistry of the d- and f-block has developed much more recently. These compounds are characterized by three types of M-C bonds (σ, π and δand their structures are impossible to deduce by chemical means alone; fundamental advances had to await the development of X-ray diffraction, as well as IR- and NMR-spectroscopy. On the other hand, elucidation of the structure of e. g. vitamin B12 and ferrocene (discovered in 1951 contributed to progress in these instrumental analytical methods, influencing further phenomenal success of transition-metal organometallic chemistry in the second half of the twentieth century. The most thoroughly explored fields of application of organometallics were in the area of catalysis, asymmetric synthesis, olefin metathesis, as well as organic synthesis and access to new materials and polymers.The most usual ligands bound to d- and f-metals are carbon monoxide, phosphines, alkyls, carbenes and arenes, and in this review the bonding patterns in the metal carbonyls and ferrocene are elaborated. The common characteristics of these two classes are two-component bonds. The CO-M bonds include (i donation from ligand HOMO to vacant M d-orbitals (σ-bond, and (ii back-donation from the filled M d-orbitals in the ligand LUMO (π-bond. Similar (but much more complicated ferrocene contains delocalized bonds consisting of electron donation from Cp to Fe (σ-bonds- and π-bonding and δ-back-bonding from metal to Cp. In such a way ferrocene, i. e. (η5-Cp2Fe contains 18 bonding electrons giving to this compound "superaromatic" properties in the sense of stability and electrophilic substitution. In contrast to benzenoid aromatic compounds reactions in two Cp-rings can occur giving homo- and heteroannularly mono-, two-… per

  20. Stereoselective coordination: a six-membered P,N-chelate tailored for asymmetric allylic alkylation.

    Science.gov (United States)

    Császár, Z; Farkas, G; Bényei, A; Lendvay, G; Tóth, I; Bakos, J

    2015-10-01

    Six-membered chelate complexes [Pd(1a-b)Cl2], (2a-b) and [Pd(1a-b)(η(3)-PhCHCHCHPh)]BF4, (3a-b) of P,N-type ligands 1a, ((2S,4S)-2-diphenyl-phosphino-4-isopropylamino-pentane) and 1b, ((2S,4S)-2-diphenyl-phosphino-4-methylamino-pentane) have been prepared. The Pd-complexes have been characterized in solution by 1D and 2D NMR spectroscopy. The observed structures were confirmed by DFT calculations and in the case of 2a also by X-ray crystallography. Unexpectedly, the coordination of the all-carbon-backbone aminophosphine 1a resulted in not only a stereospecific locking of the donor nitrogen atom into one of the two possible configurations but also the conformation of the six-membered chelate rings containing three alkyl substituents was forced into the same single chair structure showing the axially placed isopropyl group on the coordinated N-atom. The stereodiscriminative complexation of 1a led to the formation of a palladium catalyst with a conformationally rigid chelate having a configurationally fixed nitrogen and electronically different coordination sites due to the presence of P and N donors. The stereochemically fixed catalyst provided excellent ee's (up to 96%) and activities in asymmetric allylic alkylation reactions. In contrast, the chelate rings formed by 1b exist in two different chair conformations, both containing axial methyl groups, but with the opposite configurations of the coordinated N-atom. Pd-complexes of 1b provided low enantioselectivities in similar alkylations, therefore emphasizing the importance of the stereoselective coordination of N-atoms in analogous P-N chelates. The factors determining the coordination of the ligands were also studied with respect to the chelate ring conformation and the nitrogen configuration.

  1. Does 1-Allyl-3-methylimidazolium chloride Act as a Biocompatible Solvent for Stem Bromelain?

    Science.gov (United States)

    Jha, Indrani; Bisht, Meena; Venkatesu, Pannuru

    2016-06-30

    The broader scope of ILs in chemical sciences particularly in pharmaceutical, bioanalytical and many more applications is increasing day by day. Hitherto, a very less amount of research is available in the depiction of conformational stability, activity, and thermal stability of enzymes in the presence of ILs. In the present study, the perturbation in the structure, stability, and activity of stem bromelain (BM) has been observed in the presence of 1-allyl-3-methylimidazolium chloride ([Amim][Cl]) using various techniques. This is the first report in which the influence of [Amim][Cl] has been studied on the enzyme BM. Fluorescence spectroscopy has been utilized to map out the changes in the environment around tryptophan (Trp) residues of BM and also to discuss the variations in the thermal stability of BM as an outcome of its interaction with the IL at different concentrations. Further, the work delineates the denaturing effect of high concentration of IL on enzyme structure and activity. It dictates the fact that low concentrations (0.01-0.10 M) of [Amim][Cl] are only changing the structural arrangement of the protein without having harsh consequences on its activity and stability. However, high concentrations of IL proved to be totally devastating for both activity and stability of BM. The observed decrease in the stability of BM at high concentration may be due to the combined effect of cation and anion interactions with the protein residues. The present work is successful in dictating the probable mechanism of interaction between BM and [Amim][Cl]. These results can prove to be fruitful in the studies of enzymes in aqueous IL systems since the used IL is thermally stable and nonvolatile in nature thereby providing a pathway of alteration in the activity of enzymes in potentially green systems. PMID:27268069

  2. [Characterization of surface properties of 1-allyl-3-methylimidazolium chloride ionic liquid by inverse gas chromatography].

    Science.gov (United States)

    Chen, Yali; Wang, Qiang; Deng, Lishuang; Zhang, Zhengfang; Tang, Jun

    2013-02-01

    The determination of the dispersive component of surface free energies (gamma(s)d) at different temperatures and Lewis acid-base parameters of 1-allyl-3-methylimidazolium chloride ionic liquid ([AMIM]Cl) were investigated by means of inverse gas chromatography (IGC). Four n-alkanes, including n-hexane (C6), n-heptane (C7), n-octane (C8) and n-nonane (C9), were chosen as the apolar probes to characterize the dispersive component of the surface free energies at 343.15, 353.15, 363.15 and 373.15 K, respectively; and dichloromethane (DCM), trichloromethane (TCM), tetrahydrofuran (THF), ethyl acetate (EtAc), acetone (Acet) as the polar probes to estimate the Lewis acid-base parameters to judge the interactions between [AMIM] Cl and the solvents. The IGC characterizations encompassed the adsorption thermodynamic parameters to acid-base surface interactions, including the standard enthalpy (deltaHa(s)) and the free energy change of adsorption (deltaGa(s)) at different temperatures. The results showed that the Lewis acid parameter Ka of [AMIM] Cl was 0.34, and the base parameter Kb was 1.68, which indicated it was Lewis amphoteric with predominantly basic character. Furthermore, the free energy of adsorption deltaGa(s) was also figured out. It was found that the gamma(s)d of the [AMIM] Cl were 52.26, 50.82, 46.08 and 42.05 mJ/m2 at 343.15, 353.15, 363.15 and 373.15 K, respectively. The results are of great importance to the study of the surface properties and the application of ionic liquid.

  3. Antibacterial activity of starch/acrylamide/allyl triphenyl phosphonium bromide copolymers synthesized by gamma irradiation

    International Nuclear Information System (INIS)

    Starch/acrylamide/allyl triphenyl phosphonium bromide (St/AM/TP) copolymers were synthesized by simultaneous gamma irradiation and characterized by FTIR and 1H NMR techniques, weight measurement and titration method. Moreover, their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. At St/AM/TP 6:8.4:5.6 g, copolymers with higher graft ratio (G) and higher (AM+TP) graft efficiency (EAM+TP) were obtained at 3 and 6 kGy, while cationic degree (CD) and TP graft efficiency (ETP) continuously increased with absorbed dose from 1 to 6 kGy. All of the copolymers were capable of killing >99.75% of 107 CFU/ml S. aureus within 30 mins. Moreover, at 3 kGy, G, EAM+TP and ETP increased with AM/TP from 0:14 to 11.2:2.8 g at St/(AM+TP) 6:14 g, while the optimum CD and antibacterial activity were achieved at AM/TP 7:7 and 8.4:5.6 g. In addition, at 3 kGy, G, EAM+TP and CD increased with St/(AM+TP) from 6:3 to 6:18 g at AM/TP 8.4:5.6 g, while the optimum antibacterial activity was achieved at 6:10 to 6:18 g, and the optimum ETP was achieved at 6:14. - Highlights: • Cationic starch is prepared from AM and TP by Gamma irradiation. • Cationic starch is characterized by FTIR, NMR, weight method and titration method. • Grafting ratio and cationic degree depend on absorbed dose and composition. • Cationic starch shows good antibacterial activity against Staphylococcus aureus

  4. S-Allyl-Cysteines Reduce Amelioration of Aluminum Induced Toxicity in Rats

    Directory of Open Access Journals (Sweden)

    Sadhana Shrivastava

    2011-01-01

    Full Text Available Problem statement: Aluminum (Al is a trivalent cation found in its ionic form in most kinds of animal tissues and in natural waters everywhere. Approach: It is a potent neurotoxin and has been associated in the pathogenesis of several clinical disorders including Alzheimer’s disease. Results: The aim of the study was to demonstrate the protective effect of S-Allyl-Cysteines (SAC against Al-induced toxicity in rat model on certain biochemical parameters, lipid peroxidation and oxidative stress enzymes of white albino rats. Six rats per group were divided into various treatment groups. Group one rats were given normal saline and served as control group. Group two animals received Al as aluminum nitrate 32.5 mg (i.p. for the induction of toxicity. Group three to five received different doses of SAC (25, 50 and 100 mg kg-1 for 3 days after 24 h of Al toxicity. Rats were orally administered their respective doses every day for 3 days. Evaluations were made in blood and tissues. The activity of Acetylcholinesterase (AchE was inhibited in all the parts of brain after Al intoxication. Significant rise were observed the Activities of Serum Transaminases (AST and ALT after toxicant exposure. The activity of â-Aminolevulinic acid Dehydratase (ALAD in blood and â-Aminolevulinic Acid Synthetase (ALAS in brain was decreased after Al exposure. Al significant increased cholesterol, triglyceride, creatinine and urea level in serum. TBARS level was significantly higher and GSH content were significantly lower during toxicity. Total and esterified cholesterol in liver, kidney and brain were increased after Al exposure. Histopathological changes in liver, kidney and brain were also recouped with the therapy. Conclusion/Recommendations: Our data proved that SAC which is a bioactive and bioavailable component of garlic has organosulfur compounds which regulates the thiol status of the cell and scavenges free radicals and work as an antioxidant. Thus SAC

  5. Proton conductive membranes based on poly (styrene-co-allyl alcohol semi-IPN

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Moro Loureiro

    2014-01-01

    Full Text Available The optimization of fuel cell materials, particularly polymer membranes, for PEMFC has driven the development of methods and alternatives to achieve systems with more adequate properties to this application. The sulfonation of poly (styrene-co-allyl alcohol (PSAA, using sulfonating agent:styrene ratios of 2:1, 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, was previously performed to obtain proton conductive polymer membranes. Most of those membranes exhibited solubility in water with increasing temperature and showed conductivity of approximately 10-5 S cm-1. In order to optimize the PSAA properties, especially decreasing its solubility, semi-IPN (SIPN membranes are proposed in the present study. These membranes were obtained from the diglycidyl ether of bisphenol A (DGEBA, curing reactions in presence of DDS (4,4-diaminodiphenyl sulfone and PSAA. Different DGEBA/PSAA weight ratios were employed, varying the PSAA concentration between 9 and 50% and keeping the mass ratio of DGEBA:DDS as 1:1. The samples were characterized by FTIR and by electrochemical impedance spectroscopy. Unperturbed bands of PSAA were observed in the FTIR spectra of membranes, suggesting that chemical integrity of the polymer is maintained during the synthesis. In particular, bands involving C-C stretching (1450 cm-1, C=C (aromatic, ~ 3030 cm-1 and C-H (2818 and 2928 cm-1 were observed, unchanged after the synthesis. The disappearance or reduction of the intensity of the band at 916 cm-1, attributed to the DGEBA epoxy ring, is evidenced for all samples, indicating the epoxy ring opening and the DGEBA crosslinking. Conductivity of H3PO4 doped membranes increases with temperature, reaching 10-4 S cm-1.

  6. N-allyl epiderpride: An extremely potent SPECT radioligand for the dopamine D2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, R.M.; Mason, N.S.; Ansari, M.S. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1994-05-01

    We have previously reported that epidepride is a potent (K{sub D} 24pM) and specific SPECT radioligand for the dopamine D2 receptor which can be used to study striatal and extrastriatal dopamine D2 receptors in man. We have synthesized and evaluated the N-allyl analogue of epiderpride (APID) as a potential SPECT radioligand for the dopamine D2 receptor. In comparison to epidepride it is even more potent at the dopamine D2 receptor, the K{sub D} for APID being 11 frontal cortical homogenate. The lipophilicity, evaluated using the log kw pH 7.5, was 2.9 versus 2.05 for epidepride. Competitive binding studies using rat striatal, hippocampal and frontal cortical homogenates showed high affinity for only dopamine D2 like cerebellar ratio of 275:1 at 320 minutes post injection-similar to that seen with epidepride, but with nearly four times higher brain uptake. Of interest was the off-rate from the dopamine D2 receptor; it was 0.0046 min{sup -1} in vitro at 25{degrees}C-corresponding to an t 1/2 of 150 minutes. Studies in rhesus monkeys show an in vivo off rate (following 2.5 mg/kg raclopride IV) of about 0.0082 min{sup -1} seen that with epidepride. SPECT studies in rhesus monkeys reveal APID is a promising SPECT radioligand that appears to be similar to epidepride, but with higher brain uptake due to its more optimal lipophilicity for entry into brain.

  7. Elucidation of the regio- and chemoselectivity of enzymatic allylic oxidations with Pleurotus sapidus – conversion of selected spirocyclic terpenoids and computational analysis

    Directory of Open Access Journals (Sweden)

    Verena Weidmann

    2013-10-01

    Full Text Available Allylic oxidations of olefins to enones allow the efficient synthesis of value-added products from simple olefinic precursors like terpenes or terpenoids. Biocatalytic variants have a large potential for industrial applications, particularly in the pharmaceutical and food industry. Herein we report efficient biocatalytic allylic oxidations of spirocyclic terpenoids by a lyophilisate of the edible fungus Pleurotus sapidus. This ‘’mushroom catalysis’’ is operationally simple and allows the conversion of various unsaturated spirocyclic terpenoids. A number of new spirocyclic enones have thus been obtained with good regio- and chemoselectivity and chiral separation protocols for enantiomeric mixtures have been developed. The oxidations follow a radical mechanism and the regioselectivity of the reaction is mainly determined by bond-dissociation energies of the available allylic CH-bonds and steric accessibility of the oxidation site.

  8. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions.

    Science.gov (United States)

    Li, Weili; Liu, Linshu; Jin, Tony Z

    2012-12-01

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid and chitosan were incorporated with AIT and used to coat one side of the film. The films were subjected to different storage conditions (storage time, storage temperature, and packed or unpacked) and handling conditions (washing, abrasion, and air blowing), and the antimicrobial activity of the films against Salmonella Stanley in tryptic soy broth was determined. The films (8.16 μl of AIT per cm(2) of surface area) significantly (P packaging.

  9. Allyl- iso-propyltelluride, a new MOVPE precursor for CdTe, HgTe and (Hg,Cd)Te

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William

    2000-06-01

    The use of allyl- iso-propyltelluride as the tellurium precursor for the growth of CdTe, HgTe and (Hg,Cd)Te by metal organic vapour-phase epitaxy has been investigated. It has proved to be an efficient source of tellurium with growth rates for HgTe and (Hg,Cd)Te of up to 10 μm h -1 at 300°C. The best CdTe was grown at 4.5 μm h -1 under Me 2Cd-rich conditions at 300°C in the presence of Hg vapour.

  10. Preclinical assessment of the distribution,metabolism, and excretion of S-propargyl-cysteine, a novel H2S donor, in Sprague-Dawley rats

    Institute of Scientific and Technical Information of China (English)

    Yuan-ting ZHENG; Yi-zhun ZHU; Wei-min CAI; Jian-hua ZHU; Guo MA; Qing ZHU; Ping YANG; Bo TAN; Jin-lian ZHANG; Hai-xing SHEN; Jia-lin XU

    2012-01-01

    Aim:To study the distribution,metabolism and excretion of S-propargyl-cysteine (SPRC),a novel hydrogen sulfide (H2S) donor,after oral administration in rats.Methods:Adult Sprague-Dawley rats were used.The tissue distribution of [35S] SPRC-derived radioactivity was measured using a liquid scintillation counter.The plasma protein binding of SPRC was examined using 96-well equilibrium dialysis.The excretion of SPRC in urine,bile and feces was analyzed using the LC-MS/MS method.The major metabolites in rat biomatrices were identified using MRM information-dependent,acquisition-enhanced product ion (MRM-IDA-EPI) scans on API 4000QTrap system.Results:After oral administration of [35S] SPRC at a dose of 75 mg/kg,[35S] SPRC-derived radioactivity displayed broad biological distribution in various tissues of rats,including its target organs (heart and brain) with the highest in kidney.On the other hand,the binding of SPRC to human,rat and dog plasma protein was low.Only 2.18%±0.61% and 0.77%±0.61% of the total SPRC administered was excreted unchanged in the bile and urine.However,neither intact SPRC nor its metabolites were detected in rat feces.The major metabolic pathway in vivo (rat bile,urine,and plasma) was N-acetylation.Conclusion:The preliminary results suggest that SPRC possesses acceptable pharmacokinetic properties in rats.

  11. Concentrations of formaldehyde and other carbonyls in environments affected by incense burning.

    Science.gov (United States)

    Ho, Steven Sai Hang; Yu, Jian Zhen

    2002-10-01

    Burning incense to pay homage to deities is common in Chinese homes and temples. Air samples were collected and analyzed for carbonyls from a home and a temple in Hong Kong where incense burning occurs on a daily basis. Carbonyls in the air were trapped on a solid sorbent coated with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine, followed by thermal desorption and subsequent GC/MS analysis. The carbonyls identified include formaldehyde, acetaldehyde, acrolein, 2-furfural, benzaldehyde, glyoxal, and methylglyoxal. The levels of the above carbonyls correlate with the intensity of the incense-burning activities. The total mixing ratios of the carbonyls in the temple exceed those in the ambient air outside the temple by 11-23 times. Formaldehyde is the most abundant species, contributing to approximately 55% of the total carbonyl mixing ratios in both the temple and the home environments during incense burning. The mixing ratio of formaldehyde ranges from 108 to 346 ppbv in the temple and averages 103 ppbv in the home during incense burning. These values exceed the World Health Organization (WHO) air quality guideline of 100 microg m(-3) (88 ppbv) for formaldehyde. The highest formaldehyde level in the temple exceeds the WHO guideline by 3 times at peak incense burning hours. The mixing ratio of acrolein in the temple ranges from 20 to 99 ppbv, approaching or exceeding the WHO air quality guideline of 50 microg m(-3) (22 ppbv) for acrolein. Our measurements indicate that incense burning significantly elevates the concentrations of a number of carbonyls, most notably formaldehyde and acrolein, in the surrounding environments. This study provides preliminary insights on indoor air quality problems created by incense burning.

  12. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenlie [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Department of Toxicology, Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou 510‐300 (China); Ichihara, Sahoko [Graduate School of Regional Innovation Studies, Mie University, Tsu 514‐8507 (Japan); Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514‐8507 (Japan); Chang, Jie; Zhang, Lingyi; Subramanian, Kaviarasan; Mohideen, Sahabudeen Sheik [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Ichihara, Gaku, E-mail: gak@med.nagoya-u.ac.jp [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan)

    2012-08-15

    1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8 h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs. -- Highlights: ► 1-BP increases hippocampal ROS levels and hippocampal and plasma protein carbonyls. ► 1-BP increases TPI carbonylation and decreases TPI activity in the hippocampus. ► 1-BP increases hippocampal and plasma AGE levels.

  13. The utilization of the mesoporous Ti-SBA-15 catalyst in the epoxidation of allyl alcohol to glycidol and diglycidyl ether in the water medium

    Directory of Open Access Journals (Sweden)

    Wróblewska Agnieszka

    2015-12-01

    Full Text Available This work presents the studies on the optimization the process of allyl alcohol epoxidation over the Ti-SBA-15 catalyst. The optimization was carried out in an aqueous medium, wherein water was introduced into the reaction medium with an oxidizing agent (30 wt% aqueous solution of hydrogen peroxide and it was formed in the reaction medium during the processes. The main investigated technological parameters were: the temperature, the molar ratio of allyl alcohol/hydrogen peroxide, the catalyst content and the reaction time. The main functions the process were: the selectivity of transformation to glycidol in relation to allyl alcohol consumed, the selectivity of transformation to diglycidyl ether in relation to allyl alcohol consumed, the conversion of allyl alcohol and the selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed. The analysis of the layer drawings showed that in water solution it is best to conduct allyl alcohol epoxidation in direction of glycidol (selectivity of glycidol 54 mol% at: the temperature of 10–17°C, the molar ratio of reactants 0.5–1.9, the catalyst content 2.9–4.0 wt%, the reaction time 2.7–3.0 h and in direction of diglycidyl ether (selectivity of diglycidyl ether 16 mol% at: the temperature of 18–33°C, the molar ratio of reactants 0.9–1.65, the catalyst content 2.0–3.4 wt%, the reaction time 1.7–2.6 h. The presented method allows to obtain two very valuable intermediates for the organic industry.

  14. 烯丙基异硫氰酸酯的熏蒸毒力研究%FUMIGATION ACTIVITY OF THE ALLYL ISOTHIOCYANATE

    Institute of Scientific and Technical Information of China (English)

    陈春武; 谢令德; 陈雅群; 何君; 贺艳萍

    2012-01-01

    以玉米象和赤拟谷盗作为实验对象,采用熏蒸方式对烯丙基异硫氰酸酯的毒力进行测定.结果表明,烯丙基异硫氰酸酯对所研究的两种害虫有较好的快速致死作用,同时研究发现在相同熏蒸时间内烯丙基异硫氰酸酯对玉米象熏蒸的LC50和LC99均小于对赤拟谷盗的LC50和LC99,这说明烯丙基异硫氰酸酯对玉米象的熏蒸效果比对赤拟谷盗的好.%Chosing Si tophilus zesmais (Motschulsky) and Tribolium castaneun (Herbst) as experimental objects, the toxicity for the allyl isothiocyanate (AITC) is tested systematically by fumigation method. The result demonstrates that the allyl isothiocyanate presents rapid lethal effect against both of the two types of insects. The research also shows that both the LC50 and the LC99 of the fumigation of the allyl isothiocyanate to the Sitophilus zeamais are less than those of the allyl isothiocyanate to the Tribolium castaneum exposuring the same fumigating time, which indicates that the fumigating effect of the allyl isothiocyanate to the Sitophilus zeamais is more effective than that of the allyl isothiocyanate to the Tribolium castaneum.

  15. Positive trends in Southern Hemisphere observations of carbonyl sulfide

    Science.gov (United States)

    Kremser, Stefanie; Jones, Nicholas; Smale, Dan; Palm, Mathias; Lejeune, Bernard; Wang, Yuting; Deutscher, Nicholas

    2016-04-01

    Carbonyl sulfide (OCS; lifetime of about 5.7 years) is the longest lived reduced sulfur-containing gas in the atmosphere. The primary source of OCS is the ocean, which is both a direct source (through OCS emission) and an indirect source (due to oxidation of carbon disulfide, CS2, and dimethyl sulfide). Other natural sources of OCS include volcanic outgassing and direct fluxes from wetland regions. The removal of OCS from the atmosphere is dominated by soil and vegetation uptake, with minor contributions from reactions with the hydroxyl radical. Small anthropogenic sources of OCS are coal combustion, biomass burning, and aluminum production. A dominant indirect source results from CS2 emissions from the rayon industry. Transport of tropospheric OCS to the stratosphere during volcanically quiescent periods has been suggested to contribute sulfur to the stratospheric aerosol layer which affects atmospheric radiative balance. If, however, production of stratospheric aerosols from OCS oxidation is smaller than typical estimates, this OCS contribution would be overestimated. The magnitude of the OCS flux to the stratosphere is currently not well quantified as is the relative contribution of OCS to background aerosol loading. While earlier model simulations indicate OCS fluxes into the atmosphere exceeding removal, past total column observations of OCS show no significant trend. Analysis of tropospheric OCS columns at Arrival Heights (Antarctica) and Lauder (New Zealand) show strong positive trends from 2001-2008 followed by weaker trends to 2015, with unexpected temporal coherence. Since trends in ocean and land sources/sinks at these two sites, respectively, are unlikely to be similar, the coherence in trend structure likely results from changes in transport of OCS from the tropics to middle and high latitudes. Potential causes for OCS increases are (i) increases in tropical lower stratospheric OCS and/or (ii) strengthening of the large-scale circulation which

  16. 烯丙基苯并恶嗪改性BT树脂的研究%Study on Bismaleimide-Triazine Resin Modiifed by Allyl Benzoxazine

    Institute of Scientific and Technical Information of China (English)

    陈虹; 寇开昌; 王益群; 张宇; 卓龙海

    2014-01-01

    采用熔融缩聚法合成了烯丙基苯并恶嗪(Boz-allyl),并利用傅立叶变换红外光谱,磁共振氢谱对其表征。用动态扫描量热与热重分析研究了其固化过程及热性能,随后用其对双马来酰亚胺-三嗪树脂(BT树脂)改性,并分析了改性树脂的力学性能。结果表明,Boz-allyl存在两种固化机理,固化物5%和10%热失重温度分别为325,385℃,在800℃时质量保持率仍可达34%,说明其具有优良的热稳定性和耐烧蚀性,用其改性后BT树脂韧性明显提高,当Boz-allyl质量分数为8%时冲击和弯曲强度达到最大值,分别为11.32 kJ/m2和127.11 MPa。%An allyl benzoxazine(Boz-allyl) was synthesized by melt polycondensation method and the structures of Boz-allyl was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Using differential scanning calorimetery and thermal gravimetric analysis,the curing behavior and thermal property of it were probed. Then the bismaleimide-triazine resin modified by Boz-allyl was prepared and its mechanical properties was investigated. The results show a dual cure pattern of Boz-allyl ,while the 5%and 10%weight loss temperatures of polybenzoxazine is 325℃and 385℃respectively,with quality retention rate up to 34%at 800℃,which reveals good heat resistance and ablation resistance. The addition of Boz-allyl into BT resin significantly improves toughness and strength,its impact strength and flexural strength is up to their maximums of 11.32 kJ/m2 and 127.11 MPa when the mass fraction of Boz-allyl is 8%.

  17. Quantitative Proteomic Profiling of Muscle Type-Dependent and Age-Dependent Protein Carbonylation in Rat Skeletal Muscle Mitochondria

    OpenAIRE

    Feng, Juan; Xie, Hongwei; Meany, Danni L.; Thompson, LaDora V.; Arriaga, Edgar A.; Griffin, Timothy J.

    2008-01-01

    Carbonylation is a highly prevalent protein modification in skeletal muscle mitochondria, possibly contributing to its functional decline with age. Using quantitative proteomics, we identified mitochondrial proteins susceptible to carbonylation in a muscle type (slow- vs fast-twitch)-dependent and age-dependent manner from Fischer 344 rat skeletal muscle. Fast-twitch muscle contained twice as many carbonylated mitochondrial proteins than did slow-twitch muscle, with 22 proteins showing signif...

  18. Fructose-Induced Carbonyl/Oxidative Stress in S. cerevisiae: Involvement of TOR.

    Science.gov (United States)

    Valishkevych, Bohdana V; Vasylkovska, Ruslana A; Lozinska, Liudmyla M; Semchyshyn, Halyna M

    2016-01-01

    The TOR (target of rapamycin) signaling pathway first described in the budding yeast Saccharomyces cerevisiae is highly conserved in eukaryotes effector of cell growth, longevity, and stress response. TOR activation by nitrogen sources, in particular amino acids, is well studied; however its interplay with carbohydrates and carbonyl stress is poorly investigated. Fructose is a more potent glycoxidation agent capable of producing greater amounts of reactive carbonyl (RCS) and oxygen species (ROS) than glucose. The increased RCS/ROS production, as a result of glycoxidation in vivo, is supposed to be involved in carbonyl/oxidative stress, metabolic disorders, and lifespan shortening of eukaryotes. In this work we aim to expand our understanding of how TOR is involved in carbonyl/oxidative stress caused by reducing monosaccharides. It was found that in fructose-grown compared with glucose-grown cells the level of carbonyl/oxidative stress markers was higher. The defects in the TOR pathway inhibited metabolic rate and suppressed generation of glycoxidation products in fructose-grown yeast.

  19. Allyl thiourea as a corrosion inhibitor for cold rolled steel in H{sub 3}PO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Li Xianghong, E-mail: xianghong-li@163.com [Faculty of Science, Southwest Forestry University, Kunming 650224 (China) and Key Laboratory for Forest Resources Conservation and Use in the Southwest Mountains of China Ministry of Education, Southwest Forestry University, Kunming 650224 (China); Deng Shuduan [Faculty of Materials Engineering, Southwest Forestry University, Kunming 650224 (China); Fu Hui [Faculty of Science, Southwest Forestry University, Kunming 650224 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Allyl thiourea (ATU) acts as a good inhibitor for steel in 1.0 M H{sub 3}PO{sub 4}. Black-Right-Pointing-Pointer Inhibition efficiency increases slightly with the temperature at 0.2-0.5 mM. Black-Right-Pointing-Pointer The adsorption of ATU on steel surface obeys Langmuir adsorption isotherm. Black-Right-Pointing-Pointer ATU behaves as a mixed-type inhibitor. - Abstract: The inhibition effect of allyl thiourea (ATU) on the corrosion of cold rolled steel (CRS) in 1.0 M H{sub 3}PO{sub 4} solution at 20-50 Degree-Sign C was studied by weight loss, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that ATU is a good inhibitor, and the maximum inhibition efficiency of 0.5 mM inhibitor is higher than 95% at all studied temperatures. The adsorption of ATU obeys Langmuir adsorption isotherm. Polarisation curves show that ATU behaves as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop. The inhibition action is also evidenced by SEM.

  20. A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry.

    Science.gov (United States)

    Fukuda, Kazuo; Tojino, Mami; Goto, Kohtaro; Dohi, Hirofumi; Nishida, Yoshihiro; Mizuno, Mamoru

    2015-04-30

    Toward applications in synthetic carbohydrate chemistry, we converted our previous acid-resistant heavy fluorous tag [(Rf)3C-CH2-OH, 1] to allyl alcohol derivatives [(Rf)3C-CH2-O-(CH2)n-CH=CH-CH2-OH, 3 (n=1) or 4 (n=3)] by means of olefin cross metathesis. They were then subjected to β-glycosylation reactions by using a series of glycosyl donors, including glycosyl bromide and trichloroacetimidates. The terminal OH group in 3 and 4 was found to be β-glycosylated in moderate yield when 2,3,4,6-tetra-O-benzoyl-D-galactosyl trichloroacetimidate was used as the glycosyl donor. Upon a detachment reaction using Pd(PPh3)4, the initial heavy fluorous tag 1 was recovered in high yield (>90%) together with 1-hydroxy sugar, indicating that not only the allyl ether linkage in the glycosides but also the internal di-alkyl ether linkage in 4 be cleaved by the action of the Pd-catalyst enabling long-range olefin transmigration. Potential utility was demonstrated by using the tetra-O-benzoyl-β-D-galactosylated derivative of 3 in a series of deprotection, protection and glycosylation reactions, which were conductible in high yields without using chromatographic purification process. These findings prompt us to propose a general scheme in which the acid-resistant heavy fluorous compound 1 is applied as a recyclable tag in synthetic carbohydrate chemistry. PMID:25753904

  1. UV RADIATION INDUCED GRAFT COPOLYMERIZATION OF ALLYL ACETATE ONTO POLY(ETHYLENE TEREPHTHALATE) (PET) FILMS FOR FUEL CELL MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Mostak Ahmed; Mubarak A. Khan; Nazia Rahman; M. Anwar H. Khan

    2012-01-01

    Ultraviolet (UV)-induced graft copolymerization of allyl acetate (AA) monomer onto poly(ethylene terephthalate) (PET) films and the subsequent sulfonation on the monomer units in the grafting chain using chlorosulfonic acid (C1SO3H) were carried out to prepare proton exchange membranes (PEMs) for fuel cells.A maximum grafting value of 12.8% was found for 35 vol% allyl acetate after 3 h radiation time.Optimum concentration of ClSO3H was selected for the sulfonation reaction to be 0.05 mol/L based on the degree of sulfonation and the tensile strength studies of the membrane.The degree of sulfonation increased as the sulfonation reaction temperature and sulfonation time were increasing.The radiation grafting and the sulfonation have been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy.The maximum ion exchange capacity (IEC) of 0.04125 mmol g-1 was found at 12.1% degree of sulfonation and the maximum proton conductivity was found to be 0.035 S cm-1 at 30℃ and a relative humidity of 60%.The various physical and chemical properties of the PEMs such as water uptake,mechanical strength,thermal durability and oxidative stability were also studied.To investigate the suitability of the prepared membrane for fuel cell applications,its properties were compared with those of Nation 117.

  2. Molecular detection and in vitro antioxidant activity of S-allyl-L-cysteine (SAC) extracted from Allium sativum.

    Science.gov (United States)

    Sun, Y-E; Wang, W-D

    2016-01-01

    It is well known that Allium sativum has potential applications to clinical treatment of various cancers due to its remarkable ability in eliminating free radicals and increasing metabolism. An allyl-substituted cysteine derivative - S-allyl-L-cysteine (SAC) was separated and identified from Allium sativum. The extracted SAC was reacted with 1-pyrenemethanol to obtain pyrene-labelled SAC (Py-SAC) to give SAC fluorescence properties. Molecular detection of Py-SAC was conducted by steady-state fluorescence spectroscopy and time-resolved fluorescence method to quantitatively measure concentrations of Py-SAC solutions. The ability of removing 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical using Py-SAC was determined through oxygen radical absorbance capacity (ORAC). Results showed the activity of Py-SAC and Vitamin C (VC) with ORAC as index, the concentrations of Py-SAC and VC were 58.43 mg/L and 5.72 mg/L respectively to scavenge DPPH, and 8.16 mg/L and 1.67 mg/L to scavenge •OH respectively. Compared with VC, the clearance rates of Py-SAC to scavenge DPPH were much higher, Py-SAC could inhibit hydroxyl radical. The ability of removing radical showed a dose-dependent relationship within the scope of the drug concentration. PMID:27453278

  3. Inhibition of bladder cancer cell proliferation by allyl isothiocyanate (mustard essential oil)

    Energy Technology Data Exchange (ETDEWEB)

    Sávio, André Luiz Ventura, E-mail: savio.alv@gmail.com [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil); Nicioli da Silva, Glenda [UFOP – Universidade Federal de Ouro Preto, Escola de Farmácia, Departamento de Análises Clínicas, Ouro Preto, MG (Brazil); Salvadori, Daisy Maria Fávero [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil)

    2015-01-15

    Highlights: • AITC inhibits mutant and wild-type TP53 cell proliferation. • Morphological changes and cells debris were observed after AITC treatment in both cells. • BAX and BCL2 expression modulation was observed in wild-type TP53 cells. • BCL2, BAX and ANLN increased and S100P decreased expression was detected in mutated TP53 cells. • AITC effects in gene modulation are dependent TP53 gene status. - Abstract: Natural compounds hold great promise for combating antibiotic resistance, the failure to control some diseases, the emergence of new diseases and the toxicity of some contemporary medical products. Allyl isothiocyanate (AITC), which is abundant in cruciferous vegetables and mustard seeds and is commonly referred to as mustard essential oil, exhibits promising antineoplastic activity against bladder cancer, although its mechanism of action is not fully understood. Therefore, the aim of this study was to investigate the effects of AITC activity on bladder cancer cell lines carrying a wild type (wt; RT4) or mutated (T24) TP53 gene. Morphological changes, cell cycle kinetics and CDK1, SMAD4, BAX, BCL2, ANLN and S100P gene expression were evaluated. In both cell lines, treatment with AITC inhibited cell proliferation (at 62.5, 72.5, 82.5 and 92.5 μM AITC) and induced morphological changes, including scattered and elongated cells and cellular debris. Gene expression profiles revealed increased S100P and BAX and decreased BCL2 expression in RT4 cells following AITC treatment. T24 cells displayed increased BCL2, BAX and ANLN and decreased S100P expression. No changes in SMAD4 and CDK1 expression were observed in either cell line. In conclusion, AITC inhibits cell proliferation independent of TP53 status. However, the mechanism of action of AITC differed in the two cell lines; in RT4 cells, it mainly acted via the classical BAX/BCL2 pathway, while in T24 cells, AITC modulated the activities of ANLN (related to cytokinesis) and S100P. These data confirm

  4. Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals: stereoelectronic role of trans effect in a metal-mediated pericyclic process and a shift from homogeneous to heterogeneous catalysis during a one-pot reaction.

    Science.gov (United States)

    Vidhani, Dinesh V; Krafft, Marie E; Alabugin, Igor V

    2014-01-01

    The combination of experiments and computations reveals unusual features of stereoselective Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals. The first step, the conversion of propargyl vinyl ethers into allene aldehydes, proceeds under homogeneous conditions via a "cyclization-mediated" mechanism initiated by Rh(I) coordination at the alkyne. This path agrees well with the small experimental effects of substituents on the carbinol carbon. The key feature revealed by the computational study is the stereoelectronic effect of the ligand arrangement at the catalytic center. The rearrangement barriers significantly decrease due to the greater transfer of electron density from the catalytic metal center to the CO ligand oriented trans to the alkyne. This effect increases electrophilicity of the metal and lowers the calculated barriers by 9.0 kcal/mol. Subsequent evolution of the catalyst leads to the in situ formation of Rh(I) nanoclusters that catalyze stereoselective tautomerization. The intermediacy of heterogeneous catalysis by nanoclusters was confirmed by mercury poisoning, temperature-dependent sigmoidal kinetic curves, and dynamic light scattering. The combination of experiments and computations suggests that the initially formed allene-aldehyde product assists in the transformation of a homogeneous catalyst (or "a cocktail of catalysts") into nanoclusters, which in turn catalyze and control the stereochemistry of subsequent transformations.

  5. Influence of the Dielectric Medium on the Carbonyl Infrared Absorption Peak of Acetylferrocene

    Directory of Open Access Journals (Sweden)

    F. López-Linares

    2005-02-01

    Full Text Available The solvent effect on the position of the carbonyl vibrational stretching ofacetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in thisorganometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO proposed by Kolling. In contrast to the established trends for carbonyl groupsin organic systems, the results suggest that the continuum models for the reaction field arenot adequate and that the influence of dipolarity-polarizability described by aninhomogeneous coupling function θ (ε L(n 2 that assumes optical dielectric saturation isresponsible for the carbonyl band shift and, there is empirical evidence that the effect offield-induced intermolecular interaction on band shift, interpreted in terms of the van derWaals forces from the solvent, have a important contribution to this phenomena.

  6. Increased carbonylation, protein aggregation and apoptosis in the spinal cord of mice with experimental autoimmune encephalomyelitis

    Directory of Open Access Journals (Sweden)

    Nora I. Perrone‑Bizzozero

    2013-04-01

    Full Text Available Previous work from our laboratory implicated protein carbonylation in the pathophysiology of both MS (multiple sclerosis and its animal model EAE (experimental autoimmune encephalomyelitis. Subsequent in vitro studies revealed that the accumulation of protein carbonyls, triggered by glutathione deficiency or proteasome inhibition, leads to protein aggregation and neuronal cell death. These findings prompted us to investigate whether their association can be also established in vivo. In the present study, we characterized protein carbonylation, protein aggregation and apoptosis along the spinal cord during the course of MOG (myelin-oligodendrocyte glycoprotein35–55 peptide-induced EAE in C57BL/6 mice. The results show that protein carbonyls accumulate throughout the course of the disease, albeit by different mechanisms: increased oxidative stress in acute EAE and decreased proteasomal activity in chronic EAE. We also show a temporal correlation between protein carbonylation (but not oxidative stress and apoptosis. Furthermore, carbonyl levels are significantly higher in apoptotic cells than in live cells. A high number of juxta-nuclear and cytoplasmic protein aggregates containing the majority of the oxidized proteins are present during the course of EAE. The LC3 (microtubule-associated protein light chain 3-II/LC3-I ratio is significantly reduced in both acute and chronic EAE indicating reduced autophagy and explaining why aggresomes accumulate in this disorder. Taken together, the results of the present study suggest a link between protein oxidation and neuronal/glial cell death in vivo, and also demonstrate impaired proteostasis in this widely used murine model of MS.

  7. Ab initio determination of dark structures in radiationless transitions for aromatic carbonyl compounds.

    Science.gov (United States)

    Fang, Wei-Hai

    2008-03-01

    Mechanistic photodissociation of a polyatomic molecule has long been regarded as an intellectually challenging area of chemical physics, the results of which are relevant to atmospheric chemistry, biological systems, and many application fields. Carbonyl compounds play a unique role in the development of our understanding of the spectroscopy, photochemistry, and photophysics of polyatomic molecules and their photodissociation has been the subject of numerous studies over many decades. Upon irradiation, a molecule can undergo internal conversion (IC) and intersystem crossing (ISC) processes, besides photochemical and other photophysical processes. Transient intermediates formed in the IC and ISC radiationless processes, which are termed "dark", are not amenable to detection by conventional light absorption or emission. However, these dark intermediates play critical roles in IC and ISC processes and thus are essential to understanding mechanistic photochemistry of a polyatomic molecule. We have applied the multiconfiguration complete active space self-consistent field (CASSCF) method to determine the dark transient structures involved in radiationless processes for acetophenone and the related aromatic carbonyl compounds. The electronic and geometric structures predicted for the dark states are in a good agreement with those determined by ultrafast electron diffraction experiments. Intersection structure of different electronic states provides a very efficient "funnel" for the IC or ISC process. However, experimental determination of the intersection structure involved in radiationless transitions of a polyatomic molecule is impossible at present. We have discovered a minimum energy crossing point among the three potential energy surfaces (S1, T1, and T2) that appears to be common to a wide variety of aromatic carbonyl compounds with a constant structure. This new type of crossing point holds the key to understanding much about radiationless processes after

  8. Improvement on stability of square planar rhodium (Ⅰ) complexes for carbonylation of methanol to acetic acid

    Institute of Scientific and Technical Information of China (English)

    蒋华; 潘平来; 袁国卿; 陈新滋

    1999-01-01

    A series of square planar cis-dicarbonyl polymer coordinated rhodium complexes with uncoordinated donors near the central rhodium atoms for carbonylation of methanol to acetic acid are reported. Data of IR, XPS and thermal analysis show that these complexes are very stable. The intramolecular substitution reaction is proposed for their high stability. These complexes show excellent catalytic activity, selectivity and less erosion to the equipment for the methanol carbonylation to acetic acid. The distillation process may be used instead of flash vaporization in the manufacture of acetic acid, which reduces the investment on the equipment.

  9. Kinetics of Vapor—Phase Carbonylation of Ethanol on Ni—Zn/C Catalyst

    Institute of Scientific and Technical Information of China (English)

    PENGFeng

    2002-01-01

    A novel heterogeneous Ni-Zn/C catalyst was used for vapor-phase carbonylation of ethanol under atmospheric pressure.Experiments were designed with the elimination of mass-transfer resistances.The data of primary reaction in the carbonylation were collected with a differential tubular reactor.Power law rate models were emplyed to express the conversion of ethanol and the yields of ethyl propionated and diethyl ether.The results obtained with the models were in agreement with the experimental data.

  10. Activation of Carbonyl-Containing Molecules with Solid Lewis Acids in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Román-Leshkov, Yuriy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Chemical Engineering; Davis, Mark E. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Chemical Engineering

    2011-09-28

    Current interest in reacting carbonyl-containing molecules in aqueous media is primarily due to the growing emphasis on conversion of biomass to fuels and chemicals. Recently, solid Lewis acids have been shown to perform catalytic reactions with carbonyl-containing molecules such as sugars in aqueous media. Here, catalysis mediated by Lewis acids is briefly discussed, Lewis acid solids that perform catalysis in aqueous media are then described, and the review is concluded with a few comments on the outlook for the future.

  11. Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

    Institute of Scientific and Technical Information of China (English)

    李新学; 刘迎新; 魏雄辉

    2005-01-01

    The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

  12. First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation

    DEFF Research Database (Denmark)

    Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter

    2006-01-01

    A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.......A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation....

  13. Ab initio MO study of reaction mechanism for carbonyl migration of Co complex

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Ab initio method under the effective core potential (ECP) approximation is employed to study the reaction mechanism of carbonyl migration of the cycle of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)3 at Hartree-Fock (HF) level. The structures of the reactant, transition state and product for the reaction are determined. The energy of each stationary point is corrected at MP2/LAN2DZ//LANL2DZ+ZPE (zero-point energy) level. The calculated activation barrier is 28.89 kJ/mol.

  14. Impaired cardiac SIRT1 activity by carbonyl stress contributes to aging-related ischemic intolerance.

    Directory of Open Access Journals (Sweden)

    Chunhu Gu

    Full Text Available Reactive aldehydes can initiate protein oxidative damage which may contribute to heart senescence. Sirtuin 1 (SIRT1 is considered to be a potential interventional target for I/R injury management in the elderly. We hypothesized that aldehyde mediated carbonyl stress increases susceptibility of aged hearts to ischemia/reperfusion (I/R injury, and elucidate the underlying mechanisms with a focus on SIRT1. Male C57BL/6 young (4-6 mo and aged (22-24 mo mice were subjected to myocardial I/R. Cardiac aldehyde dehydrogenase (ALDH2, SIRT1 activity and protein carbonyls were assessed. Our data revealed that aged heart exhibited increased endogenous aldehyde/carbonyl stress due to impaired ALDH2 activity concomitant with blunted SIRT1 activity (P<0.05. Exogenous toxic aldehydes (4-HNE exposure in isolated cardiomyocyte verified that aldehyde-induced carbonyl modification on SIRT1 impaired SIRT1 activity leading to worse hypoxia/reoxygenation (H/R injury, which could all be rescued by Alda-1 (ALDH2 activator (all P<0.05. However, SIRT1 inhibitor blocked the protective effect of Alda-1 on H/R cardiomyocyte. Interestingly, myocardial I/R leads to higher carbonylation but lower activity of SIRT1 in aged hearts than that seen in young hearts (P<0.05. The application of Alda-1 significantly reduced the carbonylation on SIRT1 and markedly improved the tolerance to in vivo I/R injury in aged hearts, but failed to protect Sirt1(+/- knockout mice against myocardial I/R injury. This was verified by Alda-1 treatment improved postischemic contractile function recovery in ex vivo perfused aged but not in Sirt1(+/- hearts. Thus, aldehyde/carbonyl stress is accelerated in aging heart. These results provide a new insight that impaired cardiac SIRT1 activity by carbonyl stress plays a critical role in the increased susceptibility of aged heart to I/R injury. ALDH2 activation can restore this aging-related myocardial ischemic intolerance.

  15. POLYMER—SUPPORTED RHODIUM CATALYSTS FOR CARBONYLATION OF METHYL ACETATE TO ACETIC ANHYDRIDE

    Institute of Scientific and Technical Information of China (English)

    CHENDean; HUANGShizhuan; 等

    1993-01-01

    Two kinds of rhodium catalysts supported on cross-linked styrene-divinylbenzene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride,the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts.The apparent activation parameters were determined to be Eα=73.3KJ/mol,ΔH≠=66.3KJ/mol,ΔS≠=-28.6eu.These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.

  16. Rhodium-Catalyzed/Copper-Mediated Tandem C(sp(2))-H Alkynylation and Annulation: Synthesis of 11-Acylated Imidazo[1,2-a:3,4-a']dipyridin-5-ium-4-olates from 2H-[1,2'-Bipyridin]-2-ones and Propargyl Alcohols.

    Science.gov (United States)

    Li, Ting; Wang, Zhiqiang; Xu, Kun; Liu, Wenmin; Zhang, Xu; Mao, Wutao; Guo, Yongming; Ge, Xiaolin; Pan, Fei

    2016-03-01

    A rhodium-catalyzed/copper-mediated tandem C(sp(2))-H alkynylation and intramolecular annulation of 2H-[1,2'-bipyridin]-2-ones with propargyl alcohols for the synthesis of 11-acylated imidazo[1,2-a:3,4-a']dipyridin-5-ium-4-olates is described.

  17. Chiral N-1-adamantyl-N-trans-cinnamylaniline type ligands: synthesis and application to palladium-catalyzed asymmetric allylic alkylation of indoles.

    Science.gov (United States)

    Mino, Takashi; Nishikawa, Kenji; Asano, Moeko; Shima, Yamato; Ebisawa, Toshibumi; Yoshida, Yasushi; Sakamoto, Masami

    2016-08-21

    Such chiral phosphine-internal olefin hybrid type ligands as N-1-adamantyl-N-cinnamylaniline derivatives 1 with C(aryl)-N(amine) bond axial chirality were synthesized and utilized for the palladium-catalyzed asymmetric allylic alkylation of indoles to afford the desired products in high enantioselectivities (up to 98% ee). PMID:27425209

  18. Nickel-catalyzed enantioselective hydrovinylation of silyl-protected allylic alcohols:An efficient access to homoallylic alcohols with a chiral quaternary center

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Asymmetric hydrovinylation of silyl-protected allylic alcohols catalyzed by nickel complexes of chiral spiro phosphoramidite ligands was developed.A series of homoallylic alcohols with a chiral quaternary center were produced in high yields(up to 97%) and high enantioselectivities(up to 95% ee).The reaction provides an efficient method for preparing bifunctional compounds with a chiral quaternary carbon center.

  19. γ‐ and δ-Lactams through Palladium-Catalyzed Intramolecular Allylic Alkylation: Enantioselective Synthesis, NMR Investigation, and DFT Rationalization

    DEFF Research Database (Denmark)

    Bantreil, Xavier; Prestat, Guillaume; Moreno, Aitor;

    2011-01-01

    The Pd-catalyzed intramolecular allylic alkylation of unsaturated amides to give gamma- and delta-lactams has been studied in the presence of chiral ligands. Ligand (R)-3,5-tBu-MeOBIPHEP (MeOBIPHEP=6,6'-dimethoxybiphenyl-2,2-diyl)bis(diphenylphosphine)) afforded the best results and allowed the c...

  20. 炔基腰果酚的制备、表征及其聚合物的非等温固化动力学%Synthesis, characterization of propargyl-cardanol and non-isothermal curing kinetics of its polymer

    Institute of Scientific and Technical Information of China (English)

    吴竞; 史铁钧; 张方; 王启东; 周讯

    2014-01-01

    以3-溴丙炔、腰果酚为原料,利用相转移催化反应合成了炔基化腰果酚树脂,并用FT-IR、1H NMR对炔基化腰果酚的化学结构进行了表征,结果表明在相转移催化剂存在条件下,3-溴丙炔和腰果酚通过Williamson成醚反应成功制备了目标产物。用TG研究固化后的炔基化腰果酚树脂热稳定性能,结果表明,固化后树脂的起始降解温度为419℃,800℃时的残炭率为14%,说明其具有很好的耐热性能。根据 DSC 曲线,用 Kissinger 和Flynn-Wall-Ozawa分别计算了热固化反应活化能,分别为143.46 kJ·mol-1和145.15 kJ·mol-1,热固化反应级数都接近1,因此说明这两种模式很适合这种体系。%Propargyl cardanol was synthesized using cardanol and propargyl bromide by phase transfer catalyst reaction. The chemical structure of propargyl cardanol was characterized by FT-IR, 1H NMR. The results indicated that propargyl cardanol as target compound was obtained through the Williamson ether reaction. Thermal stabilization of poly-propargyl cardanol was evaluated with TG. The initial weight-loss temperature of cured propargyl cardanol was 419℃ and char yield at 800℃ was 14%, which illustrated that the cured propargyl cardano owned well-deserved thermal stability. According to DSC curves, curing kinetic parameters were calculated by two thermo-analysis methods of Kissinger and Flynn-Wall-Ozawa. The respective apparent activation energies were 143.46 and 145.15 kJ·mol-1 respectively and the order of curing reaction both approached to 1, which illustrated that these two kinds of mode were suitable for this system.

  1. Synthesis of the [beta]-D-glucosyl ester of [carbonyl-[sup 13]C]-indole-3-acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jakas, A.; Magnus, V. (Rudjer Boskovic Inst., Zagreb (Croatia)); Horvat, S.; Sandberg, G. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden))

    1993-10-01

    An efficient, operationally simple synthetic approach to 1-O-([carbonyl-[sup 13]C]-indole-3'-ylacetyl)-[beta]-D-glucopyranose is described. The synthesis was carried out by fusing a fully benzylated 1-O-glucosylpseudourea intermediate with [carbonyl-[sup 13]C]-indole-3-acetic acid, followed by hydrogenolytic removal of the protective groups. (Author).

  2. Regiospecific oxidation of an alkyl group of aromatic amine to carbonyl group by DDQ in aq.medium

    Institute of Scientific and Technical Information of China (English)

    Madhav S. Mane; Ravi S. Balaskar; Sandip N. Gavade; Pramod N. Pabrekar; Murlidhar S. Shingare; Dhananjay V. Mane

    2011-01-01

    The regiospecific oxidation of alkyl group of both sterically hindered and unhindered aromatic amine to corresponding carbonyl compound was done in aq. medium by using DDQ. The optimized reaction protocol was found to be most simple, high yielding and novel method for oxidation of alkyl group of aromatic amine in to its carbonyl compound.

  3. Enhanced antioxidation and electromagnetic properties of Co-coated flaky carbonyl iron particles prepared by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yingying, E-mail: zyzlchappy1989@163.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Zhou, Wancheng [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Li, Rong [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); No. 603 Faculty, Xi’an Institute of High Technology, Xi’an 710025 (China); Mu, Yang; Qing, Yuchang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

    2015-07-15

    Highlights: • Co-coated carbonyl iron particles were prepared by electroless plating method. • The obvious weight gain of carbonyl iron was deferred to 400 °C after Co-coated. • The permeability of the Co-coated particle composite kept almost invariable. • Co-coated carbonyl iron composite reserves a better absorption after heat treatment. - Abstract: Co was successfully coated on the surface of flaky carbonyl iron particles using an electroless plating method. The morphologies, composition, as well as magnetic, antioxidation and electromagnetic properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), vibrating sample magnetometer (VSM), thermogravimetric (TG) and microwave network analyzer. TG curve shows that the obvious weight gain of carbonyl iron was deferred from 300 to 400 °C after Co-coated. In contrast to raw carbonyl iron, the Co-coated carbonyl iron shows better stability on electromagnetic properties after 300 °C heat treatment for 10 h, demonstrating that the Co coating can act as the protection of carbonyl iron.

  4. Mitochondrial ATP synthase is a target for TNBS-induced protein carbonylation in XS-106 dendritic cells.

    Science.gov (United States)

    Je, Jeong Hwan; Lee, Tae Hyung; Kim, Dong Hyun; Cho, Young Hun; Lee, Ju Hee; Kim, Soo Chan; Lee, Sang-Kyou; Lee, Jaewon; Lee, Min-Geol

    2008-06-01

    ROS are produced in dendritic cells (DCs) during antigen presentation in contact hypersensitivity (CHS). As a result, ROS cause a number of nonenzymatic protein modifications, including carbonylation, which is the most widely used marker of oxidative stress. 2,4,6-Trinitrobenzene sulfonic acid (TNBS) is a well-characterized contact allergen that results in the formation of ROS. However, proteins that are carbonylated in DCs in response to TNBS have not been identified. To study ROS-dependent protein carbonylation in response to TNBS, we used the well-established mouse DC line, XS-106. We focused on the effects of TNBS on oxidation by examining selected oxidative markers. We identified TNBS-induced ROS and myeloperoxidase (MPO) proteins and demonstrated that the increase in ROS resulted in IL-12 production. The increase in oxidation was further confirmed by an oxidation-dependent increase in protein modifications, such as carbonylation. In fact, TNBS strongly induced carbonylation of mitochondrial adenosine triphosphate (ATP) synthase in XS-106 DCs, as determined by MALDI-TOF analysis and 2-D Western blotting. ROS production and protein carbonylation were confirmed in human monocyte-derived DCs (Mo-DCs). Furthermore, glutathione (GSH) decreased ROS and protein carbonylation in Mo-DCs. Carbonylation of ATP synthase in DCs may contribute to the pathophysiology of CHS.

  5. Dormancy alleviation by NO or HCN leading to decline of protein carbonylation levels in apple (Malus domestica Borkh.) embryos.

    Science.gov (United States)

    Krasuska, Urszula; Ciacka, Katarzyna; Dębska, Karolina; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-08-15

    Deep dormancy of apple (Malus domestica Borkh.) embryos can be overcome by short-term pre-treatment with nitric oxide (NO) or hydrogen cyanide (HCN). Dormancy alleviation of embryos modulated by NO or HCN and the first step of germination depend on temporary increased production of reactive oxygen species (ROS). Direct oxidative attack on some amino acid residues or secondary reactions via reactive carbohydrates and lipids can lead to the formation of protein carbonyl derivatives. Protein carbonylation is a widely accepted covalent and irreversible modification resulting in inhibition or alteration of enzyme/protein activities. It also increases the susceptibility of proteins to proteolytic degradation. The aim of this work was to investigate protein carbonylation in germinating apple embryos, the dormancy of which was removed by pre-treatment with NO or HCN donors. It was performed using a quantitative spectrophotometric method, while patterns of carbonylated protein in embryo axes were analyzed by immunochemical techniques. The highest concentration of protein carbonyl groups was observed in dormant embryos. It declined in germinating embryos pre-treated with NO or HCN, suggesting elevated degradation of modified proteins during seedling formation. A decrease in the concentration of carbonylated proteins was accompanied by modification in proteolytic activity in germinating apple embryos. A strict correlation between the level of protein carbonyl groups and cotyledon growth and greening was detected. Moreover, direct in vitro carbonylation of BSA treated with NO or HCN donors was analyzed, showing action of both signaling molecules as protein oxidation agents.

  6. Photopromoted carbonylation of olefins with carbon dioxide and labelling studies with 13CO2 and 13CH3OH

    Institute of Scientific and Technical Information of China (English)

    YIN Jingmei; GAO Dabin; HU Jiehan; ZHOU Guangyun; JIA Yingping; WANG Xiangsheng

    2003-01-01

    Photopromoted carbonylation of olefins with carbon dioxide can be completed in ambient conditions (room temperatures and atmospheric pressure) by Co(OAc)2 catalysis. It was found that in carbonyl carbons of methyl ester of aliphatic acid 50% is from CO2 and the other 50% from CH3OH by labelling experimental with 13CO2 and 13CH3OH.

  7. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Guan

    2015-11-01

    Full Text Available A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  8. Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise.

    Directory of Open Access Journals (Sweden)

    Francesca Magherini

    Full Text Available Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies.

  9. Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

    Science.gov (United States)

    A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

  10. Magnetic Silica-Supported Ruthenium Nanoparticles: An Efficient Catalyst for Transfer Hydrogenation of Carbonyl Compounds

    Science.gov (United States)

    One-pot synthesis of ruthenium nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium nano particles immobilization; the hydration of nitriles and transfer hydrogenation of carbonyl compounds occurs in hi...

  11. Levels, sources and health risks of carbonyls and BTEX in the ambient air of Beijing, China

    Institute of Scientific and Technical Information of China (English)

    Yujie Zhang; Yujing Mu; Junfeng Liu; Abdelwahid Mellouki

    2012-01-01

    The atmospheric concentrations of carbonyls and BTEX (benzene,toluene,ethylbenzene,m,p-xylene and o-xylene) were measured simultaneously at a same sampling site in Beijing from September 2008 to August 2010.The average concentrations of the total measured carbonyls during autumn,winter,spring,and summer were 37.7,31.3,39.7,50.5 μg/m3,respectively,and maximal values for their diurnal variations usually happened at noontime.In contrast to carbonyls,the average concentrations of the total measured BTEX during the four seasons were 27.2,31.9,23.2,19.1 μg/m3,respectively,and minimal values for their diurnal variations always occurred in the early afternoon.The average concentration for carbonyls increased about 24% from September 2008-August 2009 to September 2009-August 2010,for BTEX,increased about 15%.Integrated life time cancer risks for three carcinogens (benzene,formaldehyde and acetaldehyde) in Beijing exceeded the value of 1E-06,and the hazard quotient (HQ) of non-cancer risk of exposure to formaldehyde exceeded unity.

  12. The Palladium-Catalyzed Vinylation and Carbonylation of Bromoindoles and N-Acety1-bromoindoline

    OpenAIRE

    Kasahara, Akira; Izumi, Taeko; Ogata, Hideaki

    1989-01-01

    Abstracts The palladium-catalyzed vinylic substitution reaction of alkenes has been shown to proceed in moderate yields with 5- and 6-bromoindols, and N-acetyl-5-bromoindoline. 4-, 5-, 6-, and 7-Bromoindoles also undergo facile palladium-assisted carbonylation with carbon monoxide in methanol to produce methoxycarbonylindoles in moderate yields.

  13. Palladium-catalyzed carbonylative sonogashira coupling of aryl bromides using near stoichiometric carbon monoxide

    DEFF Research Database (Denmark)

    Neumann, Karoline T.; Laursen, Simon R.; Lindhardt, Anders T.;

    2014-01-01

    A general procedure for the palladium-catalyzed carbonylative Sonogashira coupling of aryl bromides is reported, using near stoichiometric amounts of carbon monoxide. The method allows a broad substrate scope in moderate to excellent yields. The formed alkynone motive serves as a platform for...

  14. Synthesis, spectroscopic characterizations, crystal structures and DFT studies of nalidixic acid carbonyl hydrazones derivatives

    Science.gov (United States)

    Bergamini, F. R. G.; Ribeiro, M. A.; Lancellotti, M.; Machado, D.; Miranda, P. C. M. L.; Cuin, A.; Formiga, A. L. B.; Corbi, P. P.

    2016-09-01

    This article describes the synthesis and characterization of the 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazide (hzd) and six carbonyl hydrazones derivatives of the nalidixic with 1H-pyrrol-2-ylmethylidene (hpyrr), 1H-imidazol-2-ylmethylidene (h2imi), pyridin-2-ylmethylidene (h2py), pyridin-3-ylmethylidene (h3py), pyridin-4-ylmethylidene(h4py) and (2-hydroxyphenyl)methylidene (hsali). The carbonyl hydrazones were characterized by elemental and ESI-QTOF-MS analyses, IR and detailed NMR spectroscopic measurements. The 2D NMR experiments allowed the unambiguous assignment of the hydrogen, carbon and nitrogen atoms, which have not been reported for nalidixic acid carbonyl hydrazone derivatives so far. Crystal structures of hzd and the new carbonyl hydrazones h2imi, hpyrr and h3py were determined by X-ray diffraction studies. Although the synthesis of hzd was reported decades ago, the hzd crystal structure have not been reported yet. Geometric optimizations of all the characterized structures were performed with the aid of DFT studies. Despite the fact that the hydrazones with 2-pyridine carboxylic acid (h2py) and salicyl aldehyde (hsali) were already reported by literature, a detailed spectroscopic study followed by DFT studies are also reported for such compounds in this manuscript. Antimicrobial studies of the compounds are also presented.

  15. Heterogeneous Chemistry of Carbonyls and Alcohols With Sulfuric Acid: Implications for Secondary Organic Aerosol Formation

    Science.gov (United States)

    Zhao, J.; Levitt, N.; Zhang, R.

    2006-12-01

    Recent environmental chamber studies have suggested that acid-catalyzed particle-phase reactions of organic carbonyls lead to multifold increases in secondary organic aerosol (SOA) mass and acid-catalyzed reactions between alcohols and aldehydes in the condensed phase lead to the formation of hemiacetals and acetals, also enhancing secondary organic aerosol growth. The kinetics and mechanism of the heterogeneous chemistry of carbonyls and alcohols with sulfuric acid, however, remain largely uncertain. In this talk, we present measurements of heterogeneous uptake of several carbonyls and alcohols on liquid H2SO4 in a wide range of acid concentrations and temperatures. The results indicate that uptake of larger carbonyls is explained by aldol condensation. For small dicarbonyls, heterogeneous reactions are shown to decrease with acidity and involve negligible formation of sulfate esters. Hydration and polymerization likely explain the measured uptake of such small dicarbonyls on H2SO4 and the measurements do not support an acid- catalyzed uptake. Atmospheric implications from our findings will be discussed.

  16. Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets

    Science.gov (United States)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.

    2013-09-01

    Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α,β-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

  17. Ketene as a Reaction Intermediate in the Carbonylation of Dimethyl Ether to Methyl Acetate over Mordenite

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Christensen, Jakob Munkholt; Temel, Burcin;

    2015-01-01

    Unprecedented insight into the carbonylation of dimethyl ether over Mordenite is provided through the identification of ketene (CH2CO) as a reaction intermediate. The formation of ketene is predicted by detailed DFT calculations and verified experimentally by the observation of doubly deuterated...

  18. [pi] Backbonding in Carbonyl Complexes and Carbon-Oxygen Stretching Frequencies: A Molecular Modeling Exercise

    Science.gov (United States)

    Montgomery, Craig D.

    2007-01-01

    An exercise is described that has illustrated the effect of various factors on [pi] backbonding to carbonyl ligands, where the students can view the molecular orbitals corresponding to the M-CO [pi] interaction as well as the competing interaction between the metal and co-ligands. The visual and hands-on nature of the modeling exercise has helped…

  19. Weak carbonyl-methyl intermolecular interactions in acetone clusters explored by IR plus VUV spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Jiwen [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Hu, Yongjun, E-mail: yjhu@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Xie, Min [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Bernstein, Elliot R. [Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 (United States)

    2012-09-11

    Highlights: Black-Right-Pointing-Pointer The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. Black-Right-Pointing-Pointer Acetone molecules in the dimer are stacked with an antiparallel way. Black-Right-Pointing-Pointer The structure of the acetone trimer and the tetramer are the cyclic structures. Black-Right-Pointing-Pointer The carbonyl groups would interact with the methyl groups in acetone clusters. Black-Right-Pointing-Pointer These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR-VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 {approx} 3550 cm{sup -1} of neutral acetone and its clusters (CH{sub 3}COCH{sub 3}){sub n} (n = 1-4). Features around 3440 cm{sup -1} in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm{sup -1} as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.

  20. Palladium-Catalyzed Carbonylation of Primary Amines in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 江焕峰; 陈鸣才

    2001-01-01

    The chemoselectity of the palladimm-catalyzed carbonylation of amines was affected by the addition of MeOH in supercritical carbon dioxide. The results show different selectivity in supercritical carbon dioxide CO2(sc) from that in alcohol.Methyl carbamate and its derivatives were obtained in high yields in CO2(sc).

  1. Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions.

    Science.gov (United States)

    Novacek, Johanna; Roiser, Lukas; Zielke, Katharina; Robiette, Raphaël; Waser, Mario

    2016-08-01

    The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.

  2. Oxalyl chloride as a practical carbon monoxide source for carbonylation reactions

    DEFF Research Database (Denmark)

    Hansen, Steffen V F; Ulven, Trond

    2015-01-01

    A method for generation of high-quality carbon monoxide by decomposition of oxalyl chloride in an aqueous hydroxide solution is described. The usefulness of the method is demonstrated in the synthesis of heterocycles and for hydroxy-, alkoxy-, amino-, and reductive carbonylation reactions, in sev...

  3. The adsorption stability & inhibition by allyl-thiourea of bulk nanocrystalline ingot iron in dilute HCl solution

    Science.gov (United States)

    Shen, C. B.; Wang, S. G.; Yang, H. Y.; Long, K.; Wang, F. H.

    2006-12-01

    The inhibitive effect of thiourea's (TU) alkyl derivative—allyl-thiourea (ATU) on the corrosion behaviors of bulk nanocrystalline and conventional polycrystalline ingot iron (BNII & CPII) was tested. Results indicate that BNII is less prone to get corrosive than its coarse grain counterpart in blank 1 mol L -1 HCl at room temperature. When CPII and BNII were immersed for a very short time in the corrosive solution inhibited by ATU, namely, 5 min, no inductive loop appears at different concentrations. When time became prolonged, for BNII, a Warburg impedance appeared. Inhibited by ATU, the electrodes composed of the samples are polarized anodically during the potentiodynamic polarization tests, the phenomena of desorption happens at the concentration of 100 mg L -1, but the variation between potential Edes is obvious. The inhibition effect of ATU for BNII is very limited by comparison with CPII in dilute HCl.

  4. Practical and Broadly Applicable Catalytic Enantioselective Additions of Allyl-B(pin) Compounds to Ketones and α-Ketoesters.

    Science.gov (United States)

    Robbins, Daniel W; Lee, KyungA; Silverio, Daniel L; Volkov, Alexey; Torker, Sebastian; Hoveyda, Amir H

    2016-08-01

    A set of broadly applicable methods for efficient catalytic additions of easy-to-handle allyl-B(pin) (pin=pinacolato) compounds to ketones and acyclic α-ketoesters was developed. Accordingly, a large array of tertiary alcohols can be obtained in 60 to >98 % yield and up to 99:1 enantiomeric ratio. At the heart of this development is rational alteration of the structures of the small-molecule aminophenol-based catalysts. Notably, with ketones, increasing the size of a catalyst moiety (tBu to SiPh3 ) results in much higher enantioselectivity. With α-ketoesters, on the other hand, not only does the opposite hold true, since Me substitution leads to substantially higher enantioselectivity, but the sense of the selectivity is reversed as well.

  5. Crystal structure of (E-4-(acetoxyimino-N-allyl-3-isopropyl-2,6-diphenylpiperidine-1-carbothioamide

    Directory of Open Access Journals (Sweden)

    T. Mohandas

    2015-08-01

    Full Text Available The title compound, C26H31N3O2S, crystallizes with two molecules (A and B in the asymmetric unit. In each case, the piperidine ring exists in a twist-boat conformation. The dihedral angle between the phenyl rings is 46.16 (12° in molecule A and 44.95 (12° in molecule B. In both molecules, the allyl side chain is disordered over two orientations in a 0.649 (9:0.351 (9 ratio for molecule A and 0.826 (10:0.174 (10 ratio for molecule B. In the crystal, neither molecule forms a hydrogen bond from its N—H group, presumably due to steric hindrance. A+A and B+B inversion dimers are formed, linked by pairs of weak C—H...O hydrogen bonds enclosing R22(22 ring motifs.

  6. Crystal structure of (E)-4-(acetoxyimino)-N-allyl-3-isopropyl-2,6-diphenylpiperidine-1-carbothioamide

    OpenAIRE

    Mohandas, T; K. Gokula Krishnan; Balamurugan, S.; Harrison, William T. A.; Thanikachalam, V.; Sakthivel, P.

    2015-01-01

    The title compound, C26H31N3O2S, crystallizes with two molecules (A and B) in the asymmetric unit. In each case, the piperidine ring exists in a twist-boat conformation. The dihedral angle between the phenyl rings is 46.16 (12)° in molecule A and 44.95 (12)° in molecule B. In both molecules, the allyl side chain is disordered over two orientations in a 0.649 (9):0.351 (9) ratio for molecule A and 0.826 (10):0.174 (10) ratio for molecule B. In the crystal, neither molecule forms a hydrogen bon...

  7. Improved synthesis of cyclic tertiary allylic alcohols by asymmetric 1,2-addition of AlMe3 to enones.

    Science.gov (United States)

    Kolb, Andreas; Zuo, Wei; Siewert, Jürgen; Harms, Klaus; von Zezschwitz, Paultheo

    2013-11-25

    The development of an improved protocol for the enantioselective Rh(I) /binap-catalysed 1,2-addition of AlMe3 to cyclic enones is reported. (31)P NMR analysis of the reaction revealed that the catalyst in its resting state is a chloride-bridged dimer. This insight led to the use of AgBF4 as an additive for in situ activation of the dimeric precatalyst. Thus, the catalyst loading can now be reduced to only 1 mol% with respect to rhodium. Various 5-7-membered cyclic enones can be transformed into tertiary allylic alcohols with excellent levels of enantioselectivity and high yields. The obtained products are versatile synthetic building blocks, shown by a highly enantioselective formal total synthesis of the pheromone (-)-frontalin as well as formation of a bicyclic lactone that has the core structure of the natural flavour component "wine lactone".

  8. Evaluation of hazardous airborne carbonyls on a university campus in southern China.

    Science.gov (United States)

    Ho, Steven Sai Hang; Ip, Ho Sai Simon; Ho, Kin Fai; Ng, Louisa Pan Ting; Dai, W T; Cao, Junji; Chan, Chi Sing; Ho, Legolas Baggio

    2014-08-01

    A comprehensive assessment of indoor carbonyl compounds for the academic staff workers, and students was conducted on a university campus in Xiamen, China. A total of 15 representative environment categories, including 12 indoor workplaces and three residential units, were selected. The potential indoor pollution sources were identified based on the variability in the molar compositions and correlation analyses for the target carbonyls. Furnishing materials, cooking emissions, and electronic equipment, such as photocopiers, can generate various carbonyls in the workplace. Comparison studies were conducted in the clerical offices, demonstrating that off-gases from wooden furniture and lacquer coatings, environmental tobacco smoke (ETS), and the use of cleaning reagents elevated the indoor carbonyl levels. The measured concentrations of formaldehyde and acetaldehyde in most locations surpassed the exposure limit levels. The lifetime cancer hazard risk (R) associated with formaldehyde was above the concern risk level (1 x 10(-6)) in all of the workplaces. The results indicate that formaldehyde exposure is a valid occupational health and safety concern. Wooden furniture and refurbishing materials can pose serious health threats to occupants. The information in this study could act as a basis for future indoor air quality monitoring in Mainland China. Implications: A university campus represents a microscale city environment consisting of all the working, living, and commercial needs of staff and students. The scope of this investigation covers 21 hazardous carbonyl species based on samples collected from 15 categories of workplaces and residential building in a university campus in southern China. Findings of the study provide a comprehensive assessment of indoor air quality with regards to workers' health and safety. No similar study has been carried out in China. PMID:25185393

  9. Oxi-DIGE: A novel proteomic approach for detecting and quantifying carbonylated proteins.

    Science.gov (United States)

    Baraibar, Martin; Ladouce, Romain; Friguet, Bertrand

    2014-10-01

    Proteins are involved in key cellular functions and our health and wellness depends on their quality. Accumulation of oxidatively damaged proteins is a hallmark of deleterious processes such increased oxidative stress, chronic inflammation, ageing and age-related diseases. Thus, quantifying and identifying oxidized proteins is a biomarker of choice for monitoring biological ageing and/or the efficiency of anti-oxidant, ant-inflammatory and anti-ageing therapies. However, the absence of reliable tools for analyses has inhibited its establishment as the gold standard for measuring the efficacy of anti-ageing and age related diseases interventions. Herein, we present a novel proteomics technology, named Oxi-DIGE?, which provides a significant improvement in terms of specificity, reproducibility and statistical support for proteomic analysis of carbonylated proteins. In Oxi-DIGE, protein carbonyls are labelled with fluorescent hydrazide probes that bind specifically to carbonyl groups in proteins. Experimental groups (e.g. control and experimental samples) are labelled with different flurophore-binded hydrazides that fluoresce light at different wavelengths, producing different colour fluorescence. Thus samples from different experimental groups are co-resolved on a single 2D gel. Increased accuracy is provided due to: (i) reduced false positives by using an exogenous synthetic fluorescent tag; (ii) multiplexing, that is the possibility to run multiple samples on the same gel, (iii) the use of an internal standard on each gel which eliminates inter-gel variations and provides an increased statistical confidence. In addition, the resolution of the carbonyl groups is improved, forming distinct spots that can be identified by mass spectrometry. ?Patent Application (M. Baraibar, R. Ladouce., B. Friguet, A method for detecting and/or quantifying carbonylated proteins (WO/2012/175519) filed by UPMC and referring to the technology described in this abstract. PMID:26461312

  10. Identification, quantification, and functional aspects of skeletal muscle protein-carbonylation in vivo during acute oxidative stress.

    Science.gov (United States)

    Fedorova, Maria; Kuleva, Nadezhda; Hoffmann, Ralf

    2010-05-01

    Reactive oxidative species (ROS) play important roles in cellular signaling but can also modify and often functionally inactivate other biomolecules. Thus, cells have developed effective enzymatic and nonenzymatic strategies to scavenge ROS. However, under oxidative stress, ROS production is able to overwhelm the scavenging systems, increasing the levels of functionally impaired proteins. A major class of irreversible oxidative modifications is carbonylation, which refers to reactive carbonyl-groups. In this investigation, we have studied the production and clearance rates for skeletal muscle proteins in a rat model of acute oxidative stress over a time period of 24 h using a gel-based proteomics approach. Optimized ELISA and Western blots with 10-fold improved sensitivities showed that the carbonylation level was stable at 4 nmol per mg protein 3 h following ROS induction. The carbonylation level then increased 3-fold over 6 h and then remained stable. In total, the oxidative stress changed the steady state levels of 20 proteins and resulted in the carbonylation of 38 skeletal muscle proteins. Carbonylation of these proteins followed diverse kinetics with some proteins being highly carbonylated very quickly, whereas others peaked in the 9 h sample or continued to increase up to 24 h after oxidative stress was induced. PMID:20377239

  11. Diazonium salt-mediated synthesis of new amino, hydroxy, propargyl, and maleinimido-containing superparamagnetic Fe@C nanoparticles as platforms for linking bio-entities or organocatalytic moieties

    Energy Technology Data Exchange (ETDEWEB)

    Bunge, Alexander; Magerusan, Lidia [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania); Morjan, Ion [National Institute for Lasers, Plasma and Radiation Physics (Romania); Turcu, Rodica; Borodi, Gheorghe; Liebscher, Jürgen, E-mail: liebscher@chemie.hu-berlin.de [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania)

    2015-09-15

    New magnetic Fe@C nanoparticles in the size range of about 20–50 nm functionalized with amino, hydroxy, propargyl, or maleinimido groups were synthesized by reaction with aryl diazonium salts. Aryl diazonium salts wherein the functional groups are linked via a sulfonamide moiety turned out to be advantageous over those with direct linkage. The obtained Fe@C nanoparticles represent magnetic nanoplatforms for linking bio-entities and organocatalysts using amide formation, CuAAC, or thiol-ene click chemistry as exemplified by selected examples. The Fe@C nanoparticles obtained exhibit supramolecular behavior with high value of saturation magnetization rendering them attractive for practical applications in biomedicine and organocatalysis.

  12. A Review on Mutagenicity Testing for Hazard Classification of Chemicals at Work: Focusing on in vivo Micronucleus Test for Allyl Chloride.

    Science.gov (United States)

    Rim, Kyung-Taek; Kim, Soo-Jin

    2015-09-01

    Chemical mutagenicity is a major hazard that is important to workers' health. Despite the use of large amounts of allyl chloride, the available mutagenicity data for this chemical remains controversial. To clarify the mutagenicity of allyl chloride and because a micronucleus (MN) test had not yet been conducted, we screened for MN induction by using male ICR mice bone marrow cells. The test results indicated that this chemical is not mutagenic under the test conditions. In this paper, the regulatory test battery and several assay combinations used to determine the genotoxic potential of chemicals in the workplace have been described. Further application of these assays may prove useful in future development strategies of hazard evaluations of industrial chemicals. This study also should help to improve the testing of this chemical by commonly used mutagenicity testing methods and investigations on the underlying mechanisms and could be applicable for workers' health. PMID:26929826

  13. A formal [3,3]-sigmatropic rearrangement route to quaternary alpha-vinyl amino acids: use of allylic N-PMP trifluoroacetimidates.

    Science.gov (United States)

    Berkowitz, David B; Wu, Bin; Li, Huijie

    2006-03-01

    Pd(II)-mediated rearrangement of allylic N-PMP (p-methoxyphenyl) trifluoroacetimidates provides the first formal sigmatropic route to quaternary, alpha-vinylic amino acids, potential suicide substrates for PLP enzymes. The amino acid side chains enter via transition-metal-mediated C-C bond constructions, including (i) Cu(I)-mediated conjugate addition (Ala); (ii) Pd(0)/AsPh3-mediated Stille coupling (allyl-Gly, Phe, DOPA, m-Tyr); and (iii) Pd(0)/Pt-Bu3-mediated Negishi coupling (Leu). In the synthesis of the DOPA decarboxylase inactivator, alpha-vinyl-m-tyrosine, the new N-PMP trifluoroacetimidate rearranges much more efficiently than the corresponding trichloroacetimidate.

  14. Recherches récentes sur le cobalt carbonyle et ses dérivés Recent Studies of Cobalt Carbonyl and Its Derivatives

    Directory of Open Access Journals (Sweden)

    Poilblanc R.

    2006-11-01

    Full Text Available Faisant le point sur l'ensemble de leurs résultats obtenus au cours des dernières années, les auteurs développent divers aspects relatifs aux synthèses, à la physico-chimie et aux structures des complexes dérivés des cobalt carbonyle. L'étude concerne essentiellement : - les dérivés de simple substitution de l'octacarbonyle dicobalt et la tautomérie des complexes dinucléaires; - les dérivés mononucléaires ioniques et leur relation avec les formes alkyle et acétyle du cobalt (I; - le bis (tétracarbonyle cobalt mercure et ses dérivés de substitution ; - les dérivés tétranucléaires et le phénomène de « migration intramoléculaire » des ligands. Les caractéristiques spectrographiques de quelque soixante-dix complexes sont fournies en annexe. The authors review their findings concerning the synthesis, physico-chemical properties and structural nature of cobalt carbonyl derivatives. The article deals with : - Normal substitution of Col (CO,, and tautomerism of binuclear complexes; - lonic mononuclear derivatives in relation with alkyl and acetylcobaltcarbonyls ; - Bis (tetracarbonylcobalt mercury and its substituted derivatives ; - Tetranuclear cobalt complexes exhibiting intramolecular scrambling. Spectrographic data of some 70 compounds are given.

  15. Photo-promoted carbonylation of chloroalkanes with carbon monoxide by non-precious metal catalysts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The photo-promoted carbonylation of chloroalkanes with carbon monoxide was carried out under ambient conditions with copper and cadmium salts catalysts. The results indicated that the corresponding esters were produced with three salt catalysts, i.e.CuBr2, CuCl2 and CdI2. Among these catalysts, CdI2 was the most efficient in terms of ester yield and selectivity, particularly, 60% yield and 75% selectivity in the carbonylation of chlorocyclohexane were achieved. Furthermore, the yield and selectivity of the ester can be improved greatly by adding tri-n-butylamine in the CuBr2 and CuCl2 catalyst systems. On the other hand, the additive. As a result, we suggest that iodide ion plays an important role in the catalyst system of the cadmium salts.(C) 2007 Ying Ping Jia. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  16. A catalyst for the carbonylation of methanol to acetic acid in gaseous phase

    Institute of Scientific and Technical Information of China (English)

    潘平来; 柳忠阳; 朱长城; 袁国卿

    1996-01-01

    A novel Rh/Ys catalyst for the carbonylation of methanol to acetic acid in gaseous phase is reported. The porous carbon beads (Ys) prepared from the carbonation of poly(vinylidene chloride) were used as the support. This catalyst has a specific surface area of 1 000 m2/g, high mechanical strength and thermal stability. The average diameter of the pore is in the range of 0.8 - 1.2nm. Experimental evidence showed that this catalyst was of high activity and selectivity, which could compare to those of the homogeneous catalyst from Monsanto. The catalytic rate could get to 900 g AcOH/g Rh·h during the carbonylation of methanol to acetic acid. The fine spreading of Ph over the Ys surface is the key factor for the activity.

  17. Rheological properties of magnetorheological fluid prepared by gelatin-carbonyl iron composite particles

    Institute of Scientific and Technical Information of China (English)

    PAN Hua-jin; HUANG Hong-jun; ZHANG Ling-zhen; QI Jian-ying; CAO Shao-kun

    2005-01-01

    Gelatin-carbonyl iron composite particle was prepared by micro emulsion method. The analysis of scanning electron microscope(SEM) shows that the ultrafine particles are spheroids coated by gelatin, and the average sizes of particles are 3-10 μm. The specific saturation magnetization σs is 130.9 A·m2/kg, coercivity Hc is 0.823 A/m, and residual magnetism r is 4.98 Am2/kg for the composite particles. It is shown that the particles possess properties of soft magnetic. The yield stress of magnetorheological fluid(MRF) with composite particle reaches 70 kPa at 0.5 T magnetic induction. Magnetorheological effects are superior in lower magnetic field intensity and the subsidence stability of the MRF is excellent compared with pure carbonyl iron powder.

  18. Impact of lipid content and composition on lipid oxidation and protein carbonylation in experimental fermented sausages.

    Science.gov (United States)

    Fuentes, Verónica; Estévez, Mario; Ventanas, Jesús; Ventanas, Sonia

    2014-03-15

    This study aims to investigate the effect of lipid content (∼4%, ∼10% and ∼15%) and composition (different lipid sources; animal fat and sunflower oil) on the oxidative stability of proteins and lipids in experimental fermented sausages. Increasing the lipid content of sausages enhanced the susceptibility of lipids to oxidation whereas the effect on the formation of specific carbonyls from protein oxidation was not so evident. Sausages manufactured with different lipid sources affected the susceptibility of lipids and proteins to oxidation as a likely result of the modifications in the fatty acid profile, as well as to the presence of antioxidant compounds. While the fatty acid profile had a major effect on the occurrence and extent of lipid oxidation, the presence of compounds with potential antioxidant activity may be more influential on the extent of protein carbonylation.

  19. Amino acid decarboxylations produced by lipid-derived reactive carbonyls in amino acid mixtures.

    Science.gov (United States)

    Hidalgo, Francisco J; León, M Mercedes; Zamora, Rosario

    2016-10-15

    The formation of 2-phenylethylamine and phenylacetaldehyde in mixtures of phenylalanine, a lipid oxidation product, and a second amino acid was studied to determine the role of the second amino acid in the degradation of phenylalanine produced by lipid-derived reactive carbonyls. The presence of the second amino acid usually increased the formation of the amine and reduced the formation of the Strecker aldehyde. The reasons for this behaviour seem to be related to the α-amino group and the other functional groups (mainly amino or similar groups) present in the side-chain of the amino acid. These groups are suggested to modify the lipid-derived reactive carbonyl but not the reaction mechanism because the Ea of formation of both 2-phenylethylamine and phenylacetaldehyde remained unchanged in all studied systems. All these results suggest that the amine/aldehyde ratio obtained by amino acid degradation can be modified by adding free amino acids during food formulation. PMID:27173560

  20. Influence of gamma radiation reaction on the hydroesterification of butenes catalyzed by metal carbonyls

    International Nuclear Information System (INIS)

    In the hydro carboxylation reaction, which first has been studied by Reppe, olefine and acetylene compounds are processed with carbon monoxide and water at high pressures and high temperatures in the presence of metal carbonyls. This reaction can be enhanced considerably by application of ionizing radiation. Lower pressures and in particular lower temperatures can be used if gamma irradiation is performed during carboxylation. For the experiments a mixture of buten-1 and buten-2 as well as pure buten-1 and pure buten-2 has been used to study the behaviour of these olefines with respect to the isomerization of the reaction products and to the olefines not transformed in the reaction process. Replacing water, methanol has been used as a reaction component, thus obtaining directly the respective carbonyl acid esters, which can be analysed quantitatively and qualitatively with respect to their isomeric composition by gaschromatography. (orig./HK)

  1. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing

    2010-10-12

    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested to determine the influence of CI concentration. The magnetic and mechanical properties of the magnetic elastomers were characterized, respectively, by vibrating-sample magnetometer and by tensile testing using a mechanical analyzer. The elastomer was found to exhibit high magnetization and good mechanical flexibility. The morphology and deformation of the CI-PDMS membrane also were observed. A magnetically actuated microfluidic mixer (that is, a micromixer) integrated with CI-PDMS elastomer membranes was successfully designed and fabricated. The high efficiency and quality of the mixing makes possible the impressive potential applications of this unique CI-PDMS material in microfluidic systems. © Springer-Verlag 2010.

  2. Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

    Directory of Open Access Journals (Sweden)

    Wafa Gati

    2012-12-01

    Full Text Available We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.

  3. Anti-inflammatory potential of allyl-isothiocyanate – role of Nrf2, NF-κB and microRNA-155

    OpenAIRE

    Wagner, Anika Eva; Boesch-Saadatmandi, Christine; Dose, Janina; Schultheiss, Gerhard; Rimbach, Gerald

    2012-01-01

    Abstract In this study, the underlying mechanisms of the potential anti-inflammatory properties of allyl-isothiocyanate (AITC) were analysed in vitro and in vivo. Murine RAW264.7 macrophages stimulated with lipopolysaccharide (LPS) were supplemented with increasing concentrations of AITC. In addition, C57BL/6 mice (n= 10 per group) were fed a pro-inflammatory high-fat diet and AITC was administered orally via gavage for 7 days. Biomarkers of inflammation were determined both in cultured cells...

  4. Identifying Barbiturate Binding Sites in a Nicotinic Acetylcholine Receptor with [3H]Allyl m-Trifluoromethyldiazirine Mephobarbital, a Photoreactive Barbiturate

    OpenAIRE

    Hamouda, Ayman K.; Stewart, Deirdre S.; Chiara, David C.; Savechenkov, Pavel Y.; Bruzik, Karol S.; Cohen, Jonathan B.

    2014-01-01

    At concentrations that produce anesthesia, many barbituric acid derivatives act as positive allosteric modulators of inhibitory GABAA receptors (GABAARs) and inhibitors of excitatory nicotinic acetylcholine receptors (nAChRs). Recent research on [3H]R-mTFD-MPAB ([3H]R-5-allyl-1-methyl-5-(m-trifluoromethyldiazirinylphenyl)barbituric acid), a photoreactive barbiturate that is a potent and stereoselective anesthetic and GABAAR potentiator, has identified a second class of intersubunit binding si...

  5. Palladium-Catalyzed C-H Arylation of α,β-Unsaturated Imines: Catalyst-Controlled Synthesis of Enamine and Allylic Amine Derivatives.

    Science.gov (United States)

    Li, Minyan; González-Esguevillas, María; Berritt, Simon; Yang, Xiaodong; Bellomo, Ana; Walsh, Patrick J

    2016-02-18

    A unique chemo- and regioselective α- and γ-arylation of palladium azapentadienyl intermediates is presented. Two distinct catalysts and sets of conditions successfully controlled the regioselectivity of the arylation. These methods provide the first umpolung C-H functionalization of azapentadienyl palladium intermediates and enable the divergent synthesis of allylic amine and enamine derivatives, which are of significant interest in the pharmaceutical industry. PMID:26846375

  6. The Pharmacological Activities of the Metabolites of N-[(Trimethylamineboryl)-Carbonyl]-L-Phenylalanine Methyl Ester

    OpenAIRE

    Miller, M. C.III; Sood, A.; Spielvogel, B. F.; Shrewsbury, R. P.; Hall, I. H.

    1996-01-01

    The metabolites of N-[(trimethylamineboryl)-carbonyl]-L-phenylalanine methyl ester 1 proved to be active in a number of pharmacological screens where the parent had previously demonstrated potent activity. The proposed metabolites demonstrated significant activity as cytotoxic, hypolipidemic, and anti-inflammatory agents. In cytotoxicity screens several of the proposed metabolites afforded better activity than the parent compound against the growth of suspended and solid tumor cell lines. Eva...

  7. Influence of carbonyl stress on rheological alterations of blood materials and decarbonylation effect of glutathione

    Institute of Scientific and Technical Information of China (English)

    彭密军; 蔡建光; 贺洪; 龚萍; 李国林; 汤婷; 朱泽瑞; 印大中

    2008-01-01

    The effects of various toxic carbonyls such as malondialdehyde(MDA),a secondary product of lipid peroxidation,and other aldehydes on rheological parameters and their relationship with aging-associated alterations were studied.Both MDA and glutaraldehyde(Glu) in different concentrations significantly increase viscosity,plastic viscosity and yield stress of human plasma and erythrocyte suspensions.MDA(20 mmol/L) reduces sharply the typical fluorescence of proteins(excitation 280 nm/emission 350 nm),and produces age pigment-like fluorescence with a strong emission peak at 460 nm when excites at 395 nm by only being incubated for some hours.In contrast,Glu decreases merely the fluorescence of proteins without producing age pigment-like fluorescence.These data suggest interestingly that the MDA-induced gradual protein cross linking seems to form from different mechanisms compared to the fast rheological changes of blood materials which may take place either in acute and chronic diseases or during aging.On the other hand,MDA induces various deleterious alterations of erythrocytes whereas glutathione(GSH) inhibits the MDA-related carbonyl stress in a concentration-dependent manner.The results indicate that carbonyl-amino reaction exists in the blood widely and GSH has the ability to interrupt or reverse this reaction in a certain way.It implies that carbonyl stress may be one of the important factors in blood stasis and suggests a theoretical and practical approach in anti-stresses and anti-aging.

  8. Kinetic studies on vapor phase carbonylation of methanol to acetic acid over Rh/Ys catalyst

    Institute of Scientific and Technical Information of China (English)

    柳忠阳; 潘平来; 朱长城; 袁国卿

    1997-01-01

    A novel catalyst Rh/Ys for the carbonylation of methanol to acetic acid with CH3I as the promoter shows excellent activity and selectivity.The reaction is kinetically controlled.The reaction rate is in proportion to the concentration of Rh and CH3I but has nothing to do with those of CH3OHH and CO.The surface active energy is Ea ~51.02 kJ/mol.A mechanism is also proposed.

  9. Determination of protein carbonyls in plasma, cell extracts, tissue homogenates, isolated proteins

    DEFF Research Database (Denmark)

    Weber, Daniela; Davies, Michael J.; Grune, Tilman

    2015-01-01

    in the most relevant methods to detect protein carbonyls after derivatization with 2,4-dinitrophenylhydrazine with an emphasis on measurement in plasma, cells, organ homogenates, isolated proteins and organelles. Sample preparation, derivatization conditions and protein handling are presented...... different reactive oxygen species in blood, tissues and cells. Sample preparation and stabilization are key steps in the accurate quantification of oxidation-related products and examination of physiological/pathological processes. This review therefore focuses on the sample preparation processes used...

  10. Synthesis and Insecticidal Activity of Novel N-Pyridylpyrazole Carbonyl Thioureas

    Institute of Scientific and Technical Information of China (English)

    王宝雷; 马翼; 熊丽霞; 李正名

    2012-01-01

    A series of novel N-pyridylpyrazole carbonyl thioureas were designed and synthesized. Their structures were characterized by melting points, 1H NMR, IR and elemental analysis or HRMS. The bioassay tests indicated that some of these compounds exhibited moderate insecticidal activity against Mythirnna separata Walker and Culex pipiens pallens. Among 17 compounds, 5n and 5p showed 100% larvicidal activity against Mythimna separata Walker at the test concentration of 100 mg/L.

  11. Ionization of oriented carbonyl-sulfide molecules by intense circularly polarized laser pulses

    CERN Document Server

    Dimitrovski, Darko; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Küpper, Jochen; Holmegaard, Lotte; Kalhøj, Line; Nielsen, Jens H; Stapelfeldt, Henrik

    2010-01-01

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl-sulphide molecules by circularly-polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation.

  12. Proteomic identification of carbonylated proteins in the kidney of trichloroethene-exposed MRL+/+ mice

    OpenAIRE

    Fan, Xiuzhen; WANG, GANGDUO; English, Robert D.; Khan, M. Firoze

    2013-01-01

    Trichloroethene (TCE), a common environmental and occupational pollutant, is associated with multi-organ toxicity. Kidney is one of major target organs affected as a result of TCE exposure. Our previous studies have shown that exposure to TCE causes increased protein oxidation (protein carbonylation) in the kidneys of autoimmune-prone MRL +/+ mice, and suggested a potential role of protein oxidation in TCE-mediated nephrotoxicity. To assess the impact of chronic TCE exposure on protein oxidat...

  13. Carbonyl sulfide exchange in soils for better estimates of ecosystem carbon uptake

    OpenAIRE

    Whelan, Mary E.; Hilton, Timothy W.; Berry, Joseph A; Berkelhammer, Max; Desai, Ankur R; Campbell, J. Elliott

    2016-01-01

    Carbonyl sulfide (COS) measurements are one of the emerging tools to better quantify gross primary production (GPP), the largest flux in the global carbon cycle. COS is a gas with a similar structure to CO2; COS uptake is thought to be a proxy for GPP. However, soils are a potential source or sink of COS. This study presents a framework for understanding soil–COS interactions. Excluding wetlands, most of the few observations of isolated soils that have been made show smal...

  14. Exchange of carbonyl sulfide (COS) between the atmosphere and various soils in China

    OpenAIRE

    Liu, J; C. Geng; Mu, Y; Zhang, Y.; Z. Xu; Wu, H

    2010-01-01

    Using a dynamic enclosure, the exchange rates of carbonyl sulfide (COS) between the atmosphere and 18 soils from 12 provinces in China were investigated. The emission or uptake of COS from the soils was highly dependent on the soil type, soil temperature, soil moisture, and atmospheric COS mixing ratio. In general, with the only exception being paddy soils, the soils in this investigation acted as sinks for atmospheric COS under wide ranges of soil temperature and soil moisture. Two intensive...

  15. Carbonyl sulfide exchange in soils for better estimates of ecosystem carbon uptake

    OpenAIRE

    M. E. Whelan; T. W. Hilton; J. A. Berry; M. Berkelhammer; A. R. Desai; Campbell, J. E.

    2015-01-01

    Carbonyl sulfide (COS) measurements are one of the emerging tools to better quantify gross primary production (GPP), the largest flux in the global carbon cycle. COS is a gas with a similar structure to CO2; COS uptake is thought to be a proxy for GPP. However, soils are a potential source or sink of COS. This study presents a framework for understanding soil-COS interactions. Excluding wetlands, most of the few observations of isolated soils that have been ...

  16. Exchange of carbonyl sulfide (COS) between the atmosphere and various soils in China

    OpenAIRE

    Liu, J; C. Geng; Mu, Y; Zhang, Y.; Wu, H

    2009-01-01

    Using a dynamic enclosure, the exchange fluxes of carbonyl sulfide (COS) between the atmosphere and 18 soils from 10 provinces in China were investigated. The emission or uptake of COS from the soils was highly dependent on the soil type, soil temperature, soil moisture, and atmospheric COS mixing ratio. In general, with the only exception being paddy soils, the soils in this investigation acted as sinks for atmospheric COS under wide ranges of soil temperature and soil moisture. Two i...

  17. A carnosine intervention study in overweight human volunteers: bioavailability and reactive carbonyl species sequestering effect

    OpenAIRE

    Luca Regazzoni; Barbora de Courten; Davide Garzon; Alessandra Altomare; Cristina Marinello; Michaela Jakubova; Silvia Vallova; Patrik Krumpolec; Marina Carini; Jozef Ukropec; Barbara Ukropcova; Giancarlo Aldini

    2016-01-01

    Carnosine is a natural dipeptide able to react with reactive carbonyl species, which have been recently associated with the onset and progression of several human diseases. Herein, we report an intervention study in overweight individuals. Carnosine (2 g/day) was orally administered for twelve weeks in order to evaluate its bioavailability and metabolic fate. Two carnosine adducts were detected in the urine samples of all subjects. Such adducts are generated from a reaction with acrolein, whi...

  18. Microfluidic lab-on-a-chip derivatization for gaseous carbonyl analysis.

    Science.gov (United States)

    Pang, Xiaobing; Lewis, Alastair C; Ródenas-García, Milagros

    2013-06-28

    We present a microfluidic lab-on-a-chip derivatization technique for the analysis of gaseous carbonyl compounds using O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as the derivatizing reagent. The novel microfluidic lab-on-a-chip derivatization technique has been developed to measure nmol per mole (ppbv) mixing ratios of gaseous carbonyl compounds, which are of particular importance to atmospheric chemistry. The technique utilised a planar glass microreactor comprising three inlets and one outlet, gas and fluid splitting and combining channels, mixing junctions, and a 2.0m long, 620μm internal diameter reaction microchannel. The microreactor integrated three functions, providing: (1) a gas and liquid mixer and reactor, (2) reagent heating, and (3) sample pre-concentration. The concentration of derivatization solution, the volumetric flow rates of the incoming gas sample and PFBHA solution, and the temperature of the microreactor were optimised to achieve a near real-time measurement. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the microreactor resulted in a fast and high efficiency derivatization reaction, generating an effluent stream which was ready for direct introduction to GC-MS. Good linearity was observed for eight carbonyl compounds over the measurement ranges of 1-500ppbv when they were derivatized under optimal reaction conditions. The method detection limits (MDLs) were below 0.10nmolmol(-1) for most carbonyls in this study, which is below or close to their typical concentrations in clean ambient air. The performance of the technique was assessed by applying the methodology to the quantification of glyoxal (GLY) and methylglyoxal (MGLY) formed during isoprene photo-oxidation in an outdoor photoreactor chamber (EUPHORE). Good agreements between GLY and MGLY measurements were obtained comparing this new technique with Fourier Transform InfraRed (FTIR), which provides support for the potential effectiveness of

  19. Coupling Reaction of Carbonyl Compounds Mediated by Gallium Metal in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    汪志勇; 袁仕祯; 查正根; 张祖德

    2003-01-01

    A simple and effective pinacol coupling of various aromatic aldehydes mediated by gallium in good yields has been carried out. The reaction is highly effective in water in the prurience of KOH or HCl and was strongly affected by the steric environ-ment surrounding the carbonyl group. Aliphaflc aldehydes, ke-tones and aromatic ketones appear inert under the same reac-tion conditions.

  20. Influence of shape anisotropy on microwave complex permeability in carbonyl iron flakes/epoxy resin composites

    Institute of Scientific and Technical Information of China (English)

    Wen Fu-Sheng; Qiao Liang; Zhou Dong; Zuo Wen-Liang; Yi Hai-Bo; Li Fa-Shen

    2008-01-01

    To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mossbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.

  1. COMPARATIVE STUDY OF EFFICACY OF FERROUS SULPHATE AND CARBONYL IRON IN ANEMIA OF ANTENATAL WOMEN

    OpenAIRE

    Radhika; Souris

    2015-01-01

    Iron deficiency anemia is the most common and important public health problem all over the world in the risk group of antenatal women. Research is going on to improve the iron status of the pregnant women with different forms of iron available. In this regard, Carbonyl Iron is showing promising results in improving the red cell mass with better compliance. 120 antenatal women were recruited in this study. The study comprised of 6weeks fo...

  2. Density functional theory study of electroreductive hydrocoupling of alpha,beta-unsaturated carbonyl compounds.

    Science.gov (United States)

    Kise, Naoki

    2006-11-24

    [reaction: see text] The electroreductive hydrocoupling of methyl cinnamate, methyl crotonate, cumarin, and benzalacetone was studied by DFT (B3LYP/6-311++ G**) calculations. The computational outcomes for the transition states in the hydrocoupling of anion radicals generated by a one-electron transfer to the alpha,beta-unsaturated carbonyl compounds well agree with the diastereoselectivities in the experimental results previously reported. PMID:17109548

  3. DETERMINATION OF PROTEIN CARBONYL LEVELS IN PATIENTS WITH CHRONIC ALCOHOLICS AND EVALUATION TOGETHER WITH OTHER PARAMETERS

    OpenAIRE

    YALCIN, Serap

    2011-01-01

    Investigation of the impact of oxidative stress, of which chronic alcohol consumption is an important indicator, on proteins and lipids. In this study, in order to evaluate oxidative damage, blood samples of 40 alcoholic patients, lying in the psychiatry clinic of Ankara University with the diagnosis of alcoholism, and 20 healthy people have been worked with spectrophotometric method. Malondialdehyde (MDA), lipid peroxidation product, and protein carbonyl (PCO) levels observed as statisticall...

  4. Effect of three 2-allyl-p-mentha-6,8-dien-2-ols on inhibition of mild steel corrosion in 1 M HCl

    Directory of Open Access Journals (Sweden)

    S. Kharchouf

    2014-11-01

    Full Text Available 2-Allyl-p-mentha-6,8-dien-2-ols P1−P3 synthesized from carvone P are tested as corrosion inhibitors of steel in 1 M HCl using weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS methods. The addition of 2-allyl-p-mentha-6,8-dien-2-ols reduced the corrosion rate. Potentiodynamic polarisation studies clearly reveal that the presence of inhibitors does not change the mechanism of hydrogen evolution and that they act essentially as cathodic inhibitors. 2-Allyl-p-mentha-6,8-dien-2-ols tested adsorb on the steel surface according to Langmuir isotherm. From the adsorption isotherm some thermodynamic data for the adsorption process are calculated and discussed. EIS measurements show the increase of the charge-transfer resistance with the inhibitor concentration. The highest inhibition efficiency (92% is obtained for P1 at 3 g/L. The corrosion rate decreases with the rise of temperature. The corresponding activation energies are determined.

  5. Mitochondrial ascorbate-glutathione cycle and proteomic analysis of carbonylated proteins during tomato (Solanum lycopersicum) fruit ripening.

    Science.gov (United States)

    López-Vidal, O; Camejo, D; Rivera-Cabrera, F; Konigsberg, M; Villa-Hernández, J M; Mendoza-Espinoza, J A; Pérez-Flores, L J; Sevilla, F; Jiménez, A; Díaz de León-Sánchez, F

    2016-03-01

    In non-photosynthetic tissues, mitochondria are the main source of energy and of reactive oxygen species. Accumulation of high levels of these species in the cell causes damage to macromolecules including several proteins and induces changes in different metabolic processes. Fruit ripening has been characterized as an oxidative phenomenon; therefore, control of reactive oxygen species levels by mitochondrial antioxidants plays a crucial role on this process. In this work, ascorbate-glutathione cycle components, hydrogen peroxide levels and the proteomic profile of carbonylated proteins were analyzed in mitochondria isolated from tomato (Solanum lycopersicum) fruit at two ripening stages. A significant increase on most ascorbate-glutathione cycle components and on carbonylated proteins was observed in mitochondria from breaker to light red stage. Enzymes and proteins involved in diverse cellular and mitochondrial metabolic pathways were identified among the carbonylated proteins. These results suggest that protein carbonylation is a post-translational modification involved in tomato fruit ripening regulation.

  6. Hydrogen bond and protonation during interaction of transition metal carbonyl complexes with HCl and perfluoro-tert-butanol

    International Nuclear Information System (INIS)

    Using the method of IR-spectrometry HCl interaction with some carbonyl complexes of transition metals: (Et5C5)Re(CO)3, (η6 - Me3C6H3)M(CO)3, where M = Cr, Mo, W at low temperatures in solution of liquid xenon, as well as interaction of certain complexes of Arene M (CO)L2 type with perfluoro-tert-butanol, have been investigated. It is ascertained that HCl is able to form H-bond with carbonyl Π-complexes by transition metals via oxygen atom of carbonyl group at metal atom in xenon solution. The protonation of carbonyl complexes of transition metals to metal atom can proceed via the stage of hydrogen bond formation to oxygen atom of CO group

  7. Mitochondrial ascorbate-glutathione cycle and proteomic analysis of carbonylated proteins during tomato (Solanum lycopersicum) fruit ripening.

    Science.gov (United States)

    López-Vidal, O; Camejo, D; Rivera-Cabrera, F; Konigsberg, M; Villa-Hernández, J M; Mendoza-Espinoza, J A; Pérez-Flores, L J; Sevilla, F; Jiménez, A; Díaz de León-Sánchez, F

    2016-03-01

    In non-photosynthetic tissues, mitochondria are the main source of energy and of reactive oxygen species. Accumulation of high levels of these species in the cell causes damage to macromolecules including several proteins and induces changes in different metabolic processes. Fruit ripening has been characterized as an oxidative phenomenon; therefore, control of reactive oxygen species levels by mitochondrial antioxidants plays a crucial role on this process. In this work, ascorbate-glutathione cycle components, hydrogen peroxide levels and the proteomic profile of carbonylated proteins were analyzed in mitochondria isolated from tomato (Solanum lycopersicum) fruit at two ripening stages. A significant increase on most ascorbate-glutathione cycle components and on carbonylated proteins was observed in mitochondria from breaker to light red stage. Enzymes and proteins involved in diverse cellular and mitochondrial metabolic pathways were identified among the carbonylated proteins. These results suggest that protein carbonylation is a post-translational modification involved in tomato fruit ripening regulation. PMID:26471654

  8. Synthesis, structural and vibrational properties of 1-(adamantane-1-carbonyl)-3-halophenyl thioureas

    Science.gov (United States)

    Saeed, Aamer; Erben, Mauricio F.; Bolte, Michael

    2013-02-01

    1-(Adamantane-1-carbonyl)-3-(2,4-dichlorophenyl)thiourea (1) and 1-(adamantane-1-carbonyl)-3-(2-bromo-4,6-difluorophenyl)thiourea (2) were synthesized by the reaction of adamantane-1-carbonyl chloride with ammonium thiocyanate to afford the adamantane-1-carbonylisothiocyanate in situ followed by treatment with suitable halogenated anilines. The structures of the products were established by elemental analyses, Fourier transform infrared spectroscopy (FTIR), 1H, 13C nuclear magnetic resonance (NMR), mass spectroscopy and single crystal X-ray diffraction study. Bond lengths and angles show the usual values. All of three condensed cyclohexane rings of the adamantane residues adopt the usual chair conformation. The molecular conformation of 1 and 2 is stabilized by an intramolecular (Nsbnd H⋯Odbnd C) hydrogen bond which forms a pseudo-six-membered ring. Structural features have been complemented with the joint analysis of the FTIR and FT-Raman spectra along with quantum chemical calculations at the B3LYP/6-311++G** level.

  9. Purification and characterization of a novel carbonyl reductase with high stereo-selectivity

    Institute of Scientific and Technical Information of China (English)

    YANG Ming; XU Yan; MU Xiaoqing; XIAO Rong

    2007-01-01

    A novel NADPH-dependent carbonyl reductase was separated from Candida parapsilosis CCTCC 203011.The enzyme gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE),which was purified through ammonium sulfate,Diethylamino Ethanol (DEAE) sepharose Fast flow (FF),phenyl-sepharose FF and blue sepharose FF chromatography from cell-free extract.The molecular mass of the enzyme was about 30 kDa.The optimum pH and temperature for reduction were 4.5℃ and 35℃,respectively.The Cu2+ had strong restrictive effect on enzyme activity.In addition,the carbonyl reductase was an enzyme with high substrate specificity and stereo-selectivity,and showed high asymmetric reduction activity towards α-hydroxyacetophenone and ethyl 4-chloro acetoacetate.For the asymmetric reduction of α-hydroxyacetophenone and ethyl 4-chloro acetoacetate,(S)-1-phenyl-1,2-ethanediol and (R)-ethyl 4-chloro-3-hydroxybutanoate were produced by the purified enzyme,with the 100% and 94.3% e.e.value,respectively.Therefore,the enzyme could be one of the effective biocatalysts for asymmetric synthesis of chiral alcohols.The amino acid sequences of one peptide from the purified enzyme were analyzed by LC-MASS-MASS,and the carbonyl reductase showed some identity to the hypothetical protein CaO 19.10414 reported.

  10. Blot-MS of Carbonylated Proteins: A Tool to Identify Oxidized Proteins.

    Science.gov (United States)

    Ferreira, Rita; Domingues, Pedro; Amado, Francisco; Vitorino, Rui

    2016-01-01

    The efficiency of proteostasis regulation declines during aging and the failure of protein homeostasis is common in age-related diseases. Protein oxidation is a major contributor to the loss of proteome homeostasis, also called "proteostasis," precluding protein misfolding and aggregation. So, the identification of the molecular pathways impaired by protein oxidation will increase the understanding of proteostasis and the pathophysiological conditions related to the loss of proteostasis. Sample derivatization with dinitrophenyl hydrazine and western blot immunoassay detection of carbonylated proteins (commonly known as Oxyblot™) coupled to mass spectrometry (blot-MS) is an attractive methodological approach to identify proteins that are more prone to carbonylation, a typical oxidative modification of amino acid residues. The integration of blot-MS data of carbonylated proteins with bioinformatics tools allows the identification of the biological processes more affected by protein oxidation and that, eventually, result in the loss of proteostasis.In this chapter, we describe a blot-MS methodology to identify the proteins more prone to oxidation in biological samples, as cell and tissue extracts, and biofluids. Analysis of mitochondria isolated from cardiac tissue is provided as an example. Bioinformatic strategy to deal with data retrieved from blot-MS experiments are proposed for the identification of relevant biological processes modulated by oxidative stress stimuli. PMID:27613049

  11. Effect of carbonyl inhibitors and their H₂O₂ detoxification on lactic acid fermentation.

    Science.gov (United States)

    Li, Jing; Zhu, Caiqing; Tu, Maobing; Han, Pingping; Wu, Yonnie

    2015-04-01

    Biomass degradation compounds significantly inhibit biochemical conversion of biomass prehydrolysates to biofuels and chemicals, such as lactic acid. To characterize the structure-activity relationship of carbonyl inhibition on lactic acid fermentation, we examined effects of eight carbonyl compounds (furfural, 5-hydroxymethyl furfural, vanillin, syringaldehyde, 4-hydroxybenzaldehyde, phthalaldehyde, benzoic acid, and pyrogallol aldehyde) and creosol on lactic acid production by Lactobacillus delbrueckii. Pyrogallol aldehyde reduced the cell growth rate by 35 % at 1.0 mM and inhibited lactic acid production completely at 2.0 mM. By correlating the molecular descriptors to the inhibition constants in lactic acid fermentation, we found a good relationship between the hydrophobicity (Log P) of aldehydes and their inhibition constants in fermentation. The inhibitory effect of carbonyl inhibitors appeared to correlate with their thiol reactivity as well. In addition, we found that H2O2 detoxified pyrogallol aldehyde and phthalaldehyde inhibitory activity. H2O2 detoxification was applied to real biomass prehydrolysates in lactic acid fermentation. PMID:25666370

  12. Nitrite promotes protein carbonylation and Strecker aldehyde formation in experimental fermented sausages: are both events connected?

    Science.gov (United States)

    Villaverde, A; Ventanas, J; Estévez, M

    2014-12-01

    The role played by curing agents (nitrite, ascorbate) on protein oxidation and Strecker aldehyde formation is studied. To fulfill this objective, increasing concentrations of nitrite (0, 75 and 150ppm) and ascorbate (0, 250 and 500ppm) were added to sausages subjected to a 54day drying process. The concurrence of intense proteolysis, protein carbonylation and formation of Strecker aldehydes during processing of sausages suggests that α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) may be implicated in the formation of Strecker aldehydes. The fact that nitrite (150ppm, ingoing amount) significantly promoted the formation of protein carbonyls at early stages of processing and the subsequent formation of Strecker aldehydes provides strength to this hypothesis. Ascorbate (125 and 250ppm) controlled the overall extent of protein carbonylation in sausages without declining the formation of Strecker aldehydes. These results may contribute to understanding the chemistry fundamentals of the positive influence of nitrite on the flavor and overall acceptability of cured muscle foods.

  13. Role of Protein Carbonylation in Skeletal Muscle Mass Loss Associated with Chronic Conditions

    Directory of Open Access Journals (Sweden)

    Esther Barreiro

    2016-05-01

    Full Text Available Muscle dysfunction, characterized by a reductive remodeling of muscle fibers, is a common systemic manifestation in highly prevalent conditions such as chronic heart failure (CHF, chronic obstructive pulmonary disease (COPD, cancer cachexia, and critically ill patients. Skeletal muscle dysfunction and impaired muscle mass may predict morbidity and mortality in patients with chronic diseases, regardless of the underlying condition. High levels of oxidants may alter function and structure of key cellular molecules such as proteins, DNA, and lipids, leading to cellular injury and death. Protein oxidation including protein carbonylation was demonstrated to modify enzyme activity and DNA binding of transcription factors, while also rendering proteins more prone to proteolytic degradation. Given the relevance of protein oxidation in the pathophysiology of many chronic conditions and their comorbidities, the current review focuses on the analysis of different studies in which the biological and clinical significance of the modifications induced by reactive carbonyls on proteins have been explored so far in skeletal muscles of patients and animal models of chronic conditions such as COPD, disuse muscle atrophy, cancer cachexia, sepsis, and physiological aging. Future research will elucidate the specific impact and sites of reactive carbonyls on muscle protein content and function in human conditions.

  14. A carnosine intervention study in overweight human volunteers: bioavailability and reactive carbonyl species sequestering effect

    Science.gov (United States)

    Regazzoni, Luca; de Courten, Barbora; Garzon, Davide; Altomare, Alessandra; Marinello, Cristina; Jakubova, Michaela; Vallova, Silvia; Krumpolec, Patrik; Carini, Marina; Ukropec, Jozef; Ukropcova, Barbara; Aldini, Giancarlo

    2016-06-01

    Carnosine is a natural dipeptide able to react with reactive carbonyl species, which have been recently associated with the onset and progression of several human diseases. Herein, we report an intervention study in overweight individuals. Carnosine (2 g/day) was orally administered for twelve weeks in order to evaluate its bioavailability and metabolic fate. Two carnosine adducts were detected in the urine samples of all subjects. Such adducts are generated from a reaction with acrolein, which is one of the most toxic and reactive compounds among reactive carbonyl species. However, neither carnosine nor adducts have been detected in plasma. Urinary excretion of adducts and carnosine showed a positive correlation although a high variability of individual response to carnosine supplementation was observed. Interestingly, treated subjects showed a significant decrease in the percentage of excreted adducts in reduced form, accompanied by a significant increase of the urinary excretion of both carnosine and carnosine-acrolein adducts. Altogether, data suggest that acrolein is entrapped in vivo by carnosine although the response to its supplementation is possibly influenced by individual diversities in terms of carnosine dietary intake, metabolism and basal production of reactive carbonyl species.

  15. Spatial distributions of and diurnal variations in low molecular weight carbonyl compounds in coastal seawater, and the controlling factors

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Kazuhiko, E-mail: takedaq@hiroshima-u.ac.jp [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Katoh, Shinya; Mitsui, Yumi; Nakano, Shinichi [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Nakatani, Nobutake [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Department of Environmental and Symbiotic Sciences, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069-8501 (Japan); Sakugawa, Hiroshi [Graduate School of Biosphere Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521 (Japan)

    2014-09-15

    We studied the spatial distributions of and the diurnal variations in four low molecular weight (LMW) carbonyl compounds, formaldehyde, acetaldehyde, propionaldehyde, and glyoxal, in coastal seawater. The samples were taken from the coastal areas of Hiroshima Bay, the Iyo Nada, and the Bungo Channel, western Japan. The formaldehyde, acetaldehyde, and glyoxal concentrations were higher in the northern part of Hiroshima Bay than at offshore sampling points in the Iyo Nada and the Bungo Channel. These three compounds were found at much higher concentrations in the surface water than in deeper water layers in Hiroshima Bay. It is noteworthy that propionaldehyde was not detected in any of the seawater samples, the concentrations present being lower than the detection limit (1 nanomole per liter (nM)) of the high performance liquid chromatography (HPLC) system we used. Photochemical and biological experiments were performed in the laboratory to help understand the characteristic distributions and fates of the LMW carbonyl compounds. The primary process controlling their fate in the coastal environment appears to be their biological consumption. The direct photo degradation of propionaldehyde, initiated by ultraviolet (UV) absorption, was observed, although formaldehyde and acetaldehyde were not degraded by UV irradiation. Our results suggest that the degradation of the LMW carbonyl compounds by photochemically formed hydroxyl radicals is relatively insignificant in the study area. Atmospheric deposition is a possible source of soluble carbonyl compounds in coastal surface seawater, but it may not influence the carbonyl concentrations in offshore waters. - Highlights: • Low molecular weight (LMW) carbonyl compounds in coastal seawater were determined. • Photochemical productions of LMW carbonyl compounds in seawater were observed. • LMW carbonyl compounds were largely consumed biologically. • Photochemical degradation was relatively insignificant in the study area.

  16. Cytoprotective Effects of Hydrophilic and Lipophilic Extracts of Pistacia vera against Oxidative Versus Carbonyl Stress in Rat Hepatocytes

    OpenAIRE

    Shahraki, Jafar; Zareh, Mona; Kamalinejad, Mohammad; Pourahmad, Jalal

    2014-01-01

    This study was conducted to evaluate the cytoprotection of various extracts and bioactive compounds found in Pistacia vera againts cytotoxicity, ROS formation, lipid peroxidation, protein carbonylation, mitochondrial and lysosomal membrane damages in cell toxicity models of diabetes related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, water and ethyl acetate were used to prepare crude pistachios extracts, which were then used to screen for in-vitro cytoprotection of fres...

  17. Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation

    Science.gov (United States)

    Reda, Ahmed A.; Schnelle-Kreis, J.; Orasche, J.; Abbaszade, G.; Lintelmann, J.; Arteaga-Salas, J. M.; Stengel, B.; Rabe, R.; Harndorf, H.; Sippula, O.; Streibel, T.; Zimmermann, R.

    2014-09-01

    Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6050 and 2300 μg MJ-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3500 μg MJ-1 in HFO operation to 1540 μg MJ-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls

  18. Reaction of zearalenone and α-zearalenol with allyl isothiocyanate, characterization of reaction products, their bioaccessibility and bioavailability in vitro.

    Science.gov (United States)

    Bordin, K; Saladino, F; Fernández-Blanco, C; Ruiz, M J; Mañes, J; Fernández-Franzón, M; Meca, G; Luciano, F B

    2017-02-15

    This study investigates the reduction of zearalenone (ZEA) and α-zearalenol (α-ZOL) on a solution model using allyl isothiocyanate (AITC) and also determines the bioaccessibility and bioavailability of the reaction products isolated and identified by MS-LIT. Mycotoxin reductions were dose-dependent, and ZEA levels decreased more than α-ZOL, ranging from 0.2 to 96.9% and 0 to 89.5% respectively, with no difference (p⩽0.05) between pH 4 and 7. Overall, simulated gastric bioaccessibility was higher than duodenal bioaccessibility for both mycotoxins and mycotoxin-AITC conjugates, with duodenal fractions representing ⩾63.5% of the original concentration. Simulated bioavailability of reaction products (α-ZOL/ZEA-AITC) were lower than 42.13%, but significantly higher than the original mycotoxins. The cytotoxicity of α-ZOL and ZEA in Caco-2/TC7 cells was also evaluated, with toxic effects observed at higher levels than 75μM. Further studies should be performed to evaluate the toxicity and estrogenic effect of α-ZOL/ZEA-AITC. PMID:27664682

  19. Computational insight into complex structures of thorium coordination with N, N'- bis(3-allyl salicylidene)-o-phenylenediamine.

    Science.gov (United States)

    Lan, Wenbo; Gao, Sha; Lin, Ying-Wu; Liao, Lifu; Wang, Xiaofeng; Nie, Changming

    2016-09-01

    Theoretical calculations on the structure of Th(IV) complex containing N, N'- bis(3-allyl salicylidene)-o-phenylenediamine (BASPDA) were performed using density functional theory (DFT) at the B3LYP/6-311G** level. The geometrical structural parameters and infrared spectra results of the Th(BASPDA)2 from the calculation were compared with the parallel dislocated structure (PDS) obtained in laboratory. The calculated structural parameters were in good agreement with the experimental results. In addition, based on the calculations, a stereoisomer SFS (staggered finger " + " structure) of the Th(BASPDA)2 complex was forecasted by the analysis of a comprehensive method. The charge distribution, structural parameters, bond order indices, spectral properties and thermodynamic properties as well as the molecular orbitals of the two possible crystal structures of Th(BASPDA)2 were also systematically studied. It was expected that this work could provide insightful information for understanding the properties of Th (BASPDA)2 complex at the molecular level.

  20. A dioxygenase of Pleurotus sapidus transforms (+)-valencene regio-specifically to (+)-nootkatone via a stereo-specific allylic hydroperoxidation.

    Science.gov (United States)

    Krügener, Sven; Krings, Ulrich; Zorn, Holger; Berger, Ralf G

    2010-01-01

    A selective and highly efficient allylic oxidation of the sesquiterpene (+)-valencene to the grapefruit flavour compound (+)-nootkatone was achieved with lyophilisate of the edible mushroom Pleurotus sapidus. The catalytic reaction sequence was elucidated through the identification of intermediate, (+)-valencene derived hydroperoxides. A specific staining of hydroperoxides allowed the semi-preparative isolation of two secondary (+)-valencene hydroperoxides, 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-octahydro-naphthalen-4(S)-yl-hydroperoxide and 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-octahydro-naphthalen-2(R)-yl-hydroperoxide. Chemical reduction of the biotransformation products yielded a tertiary alcohol identified as 2(R)-Isopropenyl-8(R),8a(S)-dimethyl-1,3,4,7,8,8a-hexahydro-2H-naphthalen-4a(R)-ol. This suggested a lipoxygenase-type oxidation of (+)-valencene via secondary and tertiary hydroperoxides and confirmed homology data of the key enzyme obtained previously from amino acid sequencing. PMID:19765983

  1. Influence of the antimicrobial compound allyl isothiocyanate against the Aspergillus parasiticus growth and its aflatoxins production in pizza crust.

    Science.gov (United States)

    Quiles, Juan M; Manyes, Lara; Luciano, Fernando; Mañes, Jordi; Meca, Giuseppe

    2015-09-01

    Aflatoxins (AFs) are secondary metabolites produced by different species of Aspergillus, such as Aspergillus flavus and Aspergillus parasiticus, which possess mutagenic, teratogenic and carcinogenic activities in humans. In this study, active packaging devices containing allyl isothiocyanate (AITC) or oriental mustard flour (OMF) + water were tested to inhibit the growth of A. parasiticus and AFs production in fresh pizza crust after 30 d. The antimicrobial and anti-aflatoxin activities were compared to a control group (no antimicrobial treatment) and to a group added with commercial preservatives (sorbic acid + sodium propionate). A. parasiticus growth was only inhibited after 30 d by AITC in filter paper at 5 μL/L and 10 μL/L, AITC sachet at 5 μL/L and 10 μL/L and OMF sachet at 850 mg + 850 μL of water. However, AFs production was inhibited by all antimicrobial treatments in a dose-dependent manner. More importantly, AITC in a filter paper at 10 μL/L, AITC sachet at 10 μL/L, OMF sachet at 850 mg + 850 μL of water and sorbic acid + sodium propionate at 0.5-2.0 g/Kg completely inhibited AFs formation. The use of AITC in active packaging devices could be a natural alternative to avoid the growth of mycotoxinogenic fungi in refrigerated bakery products in substitution of common commercial preservatives.

  2. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    Directory of Open Access Journals (Sweden)

    Julyana Ribeiro Garcia

    2013-04-01

    Full Text Available In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considered the entry variables and the measured properties were the response variables. The confidence level was 95% and the results were shown as response surface diagrams. It was possible to verify that the current density affected the zinc content in the coating, while the coating produced from cysteine-contained bath presented the worse anticorrosive performance. In a general way, it was possible to observe that the studied parameters affected the morphology, grain size, and the electrochemical behavior of these coatings, although only a few response variables were statistically influenced by them.

  3. Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

    Directory of Open Access Journals (Sweden)

    Julyana Ribeiro Garcia

    2012-01-01

    Full Text Available In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2³, in which these parameters were considered the entry variables and the measured properties were the response variables. The confidence level was 95% and the results were shown as response surface diagrams. It was possible to verify that the current density affected the zinc content in the coating, while the coating produced from cysteine-contained bath presented the worse anticorrosive performance. In a general way, it was possible to observe that the studied parameters affected the morphology, grain size, and the electrochemical behavior of these coatings, although only a few response variables were statistically influenced by them.

  4. Mesoporous sol-gel WO{sub 3} thin films via poly(styrene-co-allyl-alcohol) copolymer templates

    Energy Technology Data Exchange (ETDEWEB)

    Ozkan Zayim, Esra [Department of Physics, Faculty of Science and Letters, Istanbul Technical University, Maslak, Istanbul 80626 (Turkey); Liu, Ping; Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland; Deb, Satyen K. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Turner, John A.

    2003-12-01

    In this study a copolymer poly(styrene-co-allyl-alcohol), [-CH{sub 2}CH(C{sub 6}H{sub 5})-]{sub x}[-CH{sub 2}CH-(CH{sub 2}OH)-]{sub y} has been employed as a novel template in a sol-gel synthesis process to direct the formation of mesoporous tungsten oxide. The copolymer, due to its rigid hydrophobic block of polystyrene, is a more effective surfactant in an alcohol solution than polypropylene oxide-polyethylene oxide based compounds. The films have been prepared by a spin-coating technique from an ethanol solution of tungsten hexachloride. At room temperature, ultraviolet illumination method has been found to be very suitable for removing the polymer template, leading to the formation of a high-quality mesoporous structure. The electrochromic and optical properties of the mesoporous films are described and compared to standard sol-gel tungsten oxide films. Mesoporous materials exhibit superior high-rate ion-insertion performance when used as electrochromic layers.

  5. Allyl isothiocyanate that induces GST and UGT expression confers oxidative stress resistance on C. elegans, as demonstrated by nematode biosensor.

    Directory of Open Access Journals (Sweden)

    Koichi Hasegawa

    Full Text Available BACKGROUND: Electrophilic xenobiotics and endogenous products from oxidative stresses induce the glutathione S-transferases (GSTs, which form a large family within the phase II enzymes over both animal and plant kingdoms. The GSTs thus induced in turn detoxify these external as well as internal stresses. Because these stresses are often linked to ageing and damage to health, the induction of phase II enzymes without causing adverse effects would be beneficial in slowing down ageing and keeping healthy conditions. METHODOLOGY/PRINCIPAL FINDINGS: We have tested this hypothesis by choosing allyl isothiocyanate (AITC, a functional ingredient in wasabi, as a candidate food ingredient that induces GSTs without causing adverse effects on animals' lives. To monitor the GST induction, we constructed a gst::gfp fusion gene and used it to transform Caenorhabditis elegans for use as a nematode biosensor. With the nematode biosensor, we found that AITC induced GST expression and conferred tolerance on the nematode against various oxidative stresses. We also present evidence that the transcription factor SKN-1 is involved in regulating the GST expression induced by AITC. CONCLUSIONS/SIGNIFICANCE: We show the applicability of the nematode biosensor for discovering and evaluating functional food substances and chemicals that would provide anti-ageing or healthful benefits.

  6. Structure formation of soil dispersions in the presence of polyelectrolytes on the basis of allyl alcohol and acryl acid derivatives

    Directory of Open Access Journals (Sweden)

    Amankait Asanov

    2015-09-01

    Full Text Available Some changes of structural composition and surface properties of soil dispersions in the presence of polyelectrolytes, based on allyl alcohol and acryl acid derivatives, have been studied. The results show, that the changes in the structure of soil dispersions composition are connected with the added concentration and pH value, that depend on mole ratio and nature of functional groups, as well as on the nature of counterions and concomitant electrolytes, changing with the conditions of polymer analogous conversion and neutralization reaction. Experimental data show, that the change in the conformational state and the length of the macromolecule has a significant impact on the structure-forming effect and the amount of polyelectrolyte, needed to achieve the same degree of structure-forming effect of soil dispersions. The causes for the revealed reasons are shown on the basis of the results of the experiment. Along with this, it was found that particular changes of structural composition and surface properties of the soil dispersions depend on the type and concentration of the added polyelectrolyte.

  7. Synthesis, structural characterization and biological activities of organotin(IV) complexes with 5-allyl-2-hydroxy-3-methoxybenzaldehyde-4-thiosemicarbazone

    Indian Academy of Sciences (India)

    Rosenani A Haque; M A Salam

    2015-09-01

    The organotin(IV) complexes [MeSnCl(L)] (2), [BuSnCl(L)] (3), [PhSnCl(L)] (4) and [Me2Sn(L)] (5) were synthesized by reacting organotin(IV) chloride(s) with 5-allyl-2-hydroxy-3-methoxybenzaldehyde- 4-thiosemicarbazone [H2L], (1)] in presence of KOH in 1:2:1 molar ratio (metal salt: base:ligand). All the complexes have been characterized by elemental analyses, UV-Vis, FT-IR, 1H, 13C and 119Sn NMR spectral studies. The molecular structure of complex 5 has been confirmed by single crystal X-ray diffraction analysis. The ligand, H2L coordinates to Sn(IV) in thiolate form through phenoxide-O, azomethine-N and thiolate-S atoms. The C-Sn-C angle measured from coupling constant 1 (119Sn, 13C) for dimethyltin(IV) complex 5 is 123.4°. The 2 (119Sn, 1H) coupling constant values for complex 2 and 5 are 72.4 and 76.3 Hz, respectively. Proposed geometry for five coordinated Sn(IV) atom is a strongly distorted trigonal bipyramid. Biological studies were preformed in vitro against four bacterial strains which have shown better activities and potential as antibacterial agents.

  8. Influence of the antimicrobial compound allyl isothiocyanate against the Aspergillus parasiticus growth and its aflatoxins production in pizza crust.

    Science.gov (United States)

    Quiles, Juan M; Manyes, Lara; Luciano, Fernando; Mañes, Jordi; Meca, Giuseppe

    2015-09-01

    Aflatoxins (AFs) are secondary metabolites produced by different species of Aspergillus, such as Aspergillus flavus and Aspergillus parasiticus, which possess mutagenic, teratogenic and carcinogenic activities in humans. In this study, active packaging devices containing allyl isothiocyanate (AITC) or oriental mustard flour (OMF) + water were tested to inhibit the growth of A. parasiticus and AFs production in fresh pizza crust after 30 d. The antimicrobial and anti-aflatoxin activities were compared to a control group (no antimicrobial treatment) and to a group added with commercial preservatives (sorbic acid + sodium propionate). A. parasiticus growth was only inhibited after 30 d by AITC in filter paper at 5 μL/L and 10 μL/L, AITC sachet at 5 μL/L and 10 μL/L and OMF sachet at 850 mg + 850 μL of water. However, AFs production was inhibited by all antimicrobial treatments in a dose-dependent manner. More importantly, AITC in a filter paper at 10 μL/L, AITC sachet at 10 μL/L, OMF sachet at 850 mg + 850 μL of water and sorbic acid + sodium propionate at 0.5-2.0 g/Kg completely inhibited AFs formation. The use of AITC in active packaging devices could be a natural alternative to avoid the growth of mycotoxinogenic fungi in refrigerated bakery products in substitution of common commercial preservatives. PMID:26146190

  9. Recherches récentes sur le cobalt carbonyle et ses dérivés Recent Studies of Cobalt Carbonyl and Its Derivatives

    OpenAIRE

    Poilblanc R.; Attali S.; Arabi M. S.; Labroue D.; Maisonnat A.; De Montaurzon D.

    2006-01-01

    Faisant le point sur l'ensemble de leurs résultats obtenus au cours des dernières années, les auteurs développent divers aspects relatifs aux synthèses, à la physico-chimie et aux structures des complexes dérivés des cobalt carbonyle. L'étude concerne essentiellement : - les dérivés de simple substitution de l'octacarbonyle dicobalt et la tautomérie des complexes dinucléaires; - les dérivés mononucléaires ioniques et leur relation avec les formes alkyle et acétyle du cobalt (I); - le bis (tét...

  10. Carbonyl compounds in dining areas, kitchens and exhaust streams in restaurants with varying cooking methods in Kaohsiung, Taiwan.

    Science.gov (United States)

    Cheng, Jen-Hsuan; Lee, Yi-Shiun; Chen, Kang-Shin

    2016-03-01

    Eighteen carbonyl species in C1-C10 were measured in the dining areas, kitchens and exhaust streams of six different restaurant types in Kaohsiung, southern Taiwan. Measured results in the dining areas show that Japanese barbecue (45.06ppb) had the highest total carbonyl concentrations (sum of 18 compounds), followed by Chinese hotpot (38.21ppb), Chinese stir-frying (8.99ppb), Western fast-food (8.22ppb), Chinese-Western mixed style (7.38ppb), and Chinese buffet (3.08ppb), due to their different arrangements for dining and cooking spaces and different cooking methods. On average, low carbon-containing species (C1-C4), e.g., formaldehyde, acetaldehyde, acetone and butyraldehyde were dominant and contributed 55.01%-94.52% of total carbonyls in the dining areas of all restaurants. Meanwhile, Chinese-Western mixed restaurants (45.48ppb) had high total carbonyl concentrations in kitchens mainly because of its small kitchen and poor ventilation. However, high carbon-containing species (C5-C10) such as hexaldehyde, heptaldehyde and nonanaldehyde (16.62%-77.00% of total carbonyls) contributed comparatively with low carbon-containing compounds (23.01%-83.39% of total carbonyls) in kitchens. Furthermore, Chinese stir-frying (132.10ppb), Japanese barbecue (125.62ppb), Western fast-food (122.67ppb), and Chinese buffet (119.96ppb) were the four restaurant types with the highest total carbonyl concentrations in exhaust streams, indicating that stir-frying and grilling are inclined to produce polluted gases. Health risk assessments indicate that Chinese hotpot and Japanese barbecue exceeded the limits of cancer risk (10(-6)) and hazard index (=1), mainly due to high concentrations of formaldehyde. The other four restaurants were below both limits. PMID:26969068

  11. Formation and emissions of carbonyls during and following gas-phase ozonation of indoor materials

    Science.gov (United States)

    Poppendieck, D. G.; Hubbard, H. F.; Weschler, C. J.; Corsi, R. L.

    Ozone concentrations that are several orders of magnitude greater than typical urban ambient concentrations are necessary for gas-phase ozonation of buildings, either for deodorization or for disinfection of biological agents. However, there is currently no published literature on the interaction of building materials and ozone under such extreme conditions. It would be useful to understand, for example in the case of building re-occupation planning, what types and amounts of reaction products may form and persist in a building after ozonation. In this study, 24 materials were exposed to ozone at concentrations of 1000 ppm in the inlet stream of experimental chambers. Fifteen target carbonyls were selected and measured as building ozonation by-products (BOBPs). During the 36 h that include the 16 h ozonation and 20 h persistence phase, the total BOBP mass released from flooring and wall coverings ranged from 1 to 20 mg m -2, with most of the carbonyls being of lower molecular weight (C 1-C 4). In contrast, total BOBP mass released from wood-based products ranged from 20 to 100 mg m -2, with a greater fraction of the BOBPs being heavier carbonyls (C 5-C 9). The total BOBP mass released during an ozonation event is a function of both the total surface area of the material and the BOBP emission rate per unit area of material. Ceiling tile, carpet, office partition, and gypsum wallboard with flat latex paint often have large surface areas in commercial buildings and these same materials exhibited relatively high BOBP releases. The greatest overall BOBP mass releases were observed for three materials that building occupants might have significant contact with: paper, office partition, and medium density fiberboard, e.g., often used in office furniture. These materials also exhibited extended BOBP persistence following ozonation; some BOBPs (e.g., nonanal) persist for months or more at emission rates large enough to result in indoor concentrations that exceed their odor

  12. Electrochemical Dissolution Behavior and the Residue Formation Mechanism of Laboratory Made Carbonyl Nickel

    International Nuclear Information System (INIS)

    Highlights: • Why residue is formed during anodic dissolution of carbonyl nickel was explained. • Spatiotemporal pattern of pitting in anodic Ni dissolution was described. • The role of sulfur impurities on anodic Ni dissolution was explained. - Abstract: The anodic dissolution of two laboratory-made Ni samples obtained using the carbonyl method was investigated to understand the origin of residue formation in the anode basket in an electroplating tank. The first sample was obtained with 3 ppm addition of carbonyl sulfide to introduce a small amount of sulfur (CN-S sample). The second was obtained without sulfur impurities (CN sample). Linear sweep voltammetry and chronopotentiometry were applied to characterize the dissolution of these samples. The dissolution of the CN-S sample took place in the active region at low overpotentials. This behavior is determined by the presence of sulfur impurities that break down the passive layer and facilitate Ni dissolution. The CN sample without sulfur was dissolved at high overpotentials. The overpotential-time plots displayed regular large amplitude oscillations in which the overvoltage periodically moved between the transpassive and passive regimes. The anodic dissolution of this sample was controlled by two competing processes: breakdown and formation of the passive layer. Scanning electron microscopy and white light interference microscopy were applied to monitor the morphological changes of the two samples as a function of the dissolution time. The results of these studies showed that the CN-S sample dissolved uniformly across the surface. However, the roughness and the aspect ratio of the protruding features on the surface increased with time. This sample produced a fine residue due to detachment of small protruding crystallites. In contrast, the dissolution of the CN sample involved pit formation and took place predominantly from the bulk of the pits. The dissolution of this sample left a porous skeleton of more

  13. Assignment of congested NMR spectra: Carbonyl backbone enrichment via the Entner Doudoroff pathway

    Science.gov (United States)

    Goldbourt, Amir; Day, Loren A.; McDermott, Ann E.

    2007-12-01

    In NMR spectra of complex proteins, sparse isotope enrichment can be important, in that the removal of many 13C- 13C homonuclear J-couplings can narrow the lines and thereby facilitate the process of spectral assignment and structure elucidation. We present a simple scheme for selective yet extensive isotopic enrichment applicable for production of proteins in organisms utilizing the Entner-Doudoroff (ED) metabolic pathway. An enrichment scheme so derived is demonstrated in the context of a magic-angle spinning solid-state NMR (MAS SSNMR) study of Pf1 bacteriophage, the host of which is Pseudomonas aeruginosa, strain K (PAK), an organism that uses the ED pathway for glucose catabolism. The intact and infectious Pf1 phage in this study was produced by infected PAK cells grown on a minimal medium containing 1- 13C D-glucose ( 13C in position 1) as the sole carbon source, as well as 15NH 4Cl as the only nitrogen source. The 37 MDa Pf1 phage consists of about 93% major coat protein, 1% minor coat proteins, and 6% single-stranded, circular DNA. As a consequence of this composition and the enrichment scheme, the resonances in the MAS SSNMR spectra of the Pf1 sample were almost exclusively due to carbonyl carbons in the major coat protein. Moreover, 3D heteronuclear NCOCX correlation experiments also show that the amino acids leucine, serine, glycine, and tyrosine were not isotopically enriched in their carbonyl positions (although most other amino acids were), which is as expected based upon considerations of the ED metabolic pathway. 3D NCOCX NMR data and 2D 15N- 15N data provided strong verification of many previous assignments of 15N amide and 13C carbonyl shifts in this highly congested spectrum; both the semi-selective enrichment patterns and the narrowed linewidths allowed for greater certainty in the assignments as compared with use of uniformly enriched samples alone.

  14. Sol–gel method as a way of carbonyl iron powder surface modification for interaction improvement

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, P., E-mail: pawel.malecki@pwr.edu.pl [Polymer Engineering and Technology Division, W-3, Wrocław University of Technology, Smoluchowskiego 25, 50 370 Wrocław (Poland); Kolman, K.; Pigłowski, J. [Polymer Engineering and Technology Division, W-3, Wrocław University of Technology, Smoluchowskiego 25, 50 370 Wrocław (Poland); Kaleta, J. [Department of Mechanics, Materials Science and Engineering, W-10, Wrocław University of Technology, Smoluchowskiego 25, 50-370 Wrocław (Poland); Krzak, J., E-mail: justyna.krzak@pwr.edu.pl [Department of Mechanics, Materials Science and Engineering, W-10, Wrocław University of Technology, Smoluchowskiego 25, 50-370 Wrocław (Poland)

    2015-03-15

    This article presents a method for modification of carbonyl iron particles’ surface (CIP), (d{sub 50}=4–9 µm) by silica coatings obtained using the sol–gel method. Reaction parameters were determined to obtain dry magnetic powder with homogeneous silica coatings without further processing and without any by-product in the solid or liquid phase. This approach is new among the commonly used methods of silica coating of iron particles. No attempt has been made to cover a carbonyl iron surface by silica in a waste-free method, up to date. In the current work two different silica core/shell structures were made by the sol–gel process, based on different silica precursors: tetraethoxy-silane (TEOS) and tetramethoxy-silane (TMOS). The dependence between the synthesis procedure and thickness of silica shell covering carbonyl iron particles has been described. Surface morphology of the modified magnetic particles and the coating thickness were characterized with the use of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Determination of the physicochemical structure of the obtained materials was performed by the energy-dispersive X-ray spectroscope (EDS), and the infrared technique (IR). The surface composition was analyzed using X-ray photoelectron spectroscopy (XPS). Additionally, distribution of particle size was measured using light microscopy. The new, efficient process of covering micro-size CIP with a nanometric silica layer was shown. Results of a performed analysis confirm the effectiveness of the presented method. - Highlights: • Proper covering CIP by sol–gel silica layer avoids agglomeration. • A new solid waste-free method of CIP coating is proposed. • Examination of the properties of modified CIP in depends on washing process. • Coatings on CIP particles doesn’t change the magnetic properties of particles.

  15. Electromagnetic properties of carbonyl iron and their microwave absorbing characterization as filler in silicone rubber

    Indian Academy of Sciences (India)

    Yuping Duan; Guofang Li; Lidong Liu; Shunhua Liu

    2010-10-01

    The complex permittivity, permeability and microwave-absorbing properties of rubber composites filled with carbonyl iron are measured at frequencies from 2–18 GHz. The results indicate that the reflection loss peak shifts towards low frequency region with increasing layer thickness or increasing weight concentration. The minimum reflection loss value of –23.06 dB was obtained at 3.3 GHz for the composites with 80% wt. These results show that the composites possess good microwave absorbing ability in both low- and highfrequency bands.

  16. Determination of carbonyl compounds in air by HPLC; Determinacion de compuestos carbonilicos en aire por HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, S.; Perez, R.M.; Campos, A.; Gonzalez, D.

    1995-07-01

    A method for the determination of seven carbonyl compounds in air is presented. The procedure involve sampling of air by a Sep-Pak Cartridge impregnated with 2,4-dinitrophenylhydrazine. Elution was done with 3 mL of acetonitrile and the eluate was diluted to 5 mL. The analysis was done by HPLC with UV detection and external standard method quantification. It has been achieved relative standard deviations about 5% and detection limits of 80 ng/cartridge for formaldehyde, acetaldehyde and acetoacetonitrile. Three different types of samples (rural, urban, petrol emission) were successfully analyzed. (Author) 12 refs.

  17. Calculation of High Frequency Complex Permeability of Carbonyl Iron Flakes in a Nomagnetic Matrix

    Institute of Scientific and Technical Information of China (English)

    WEN Fu-Sheng; QIAO Liang; YI Hai-Bo; ZHOU Dong; LI Fa-Shen

    2008-01-01

    The carbonyl iron flakes are fabricated by high-energy ball milling.The effective permeability is measured and calculated for the composite consisting of flakes embedded in a nonmagnetic matrix.The magnetic flakes with a shape anisotropy and random spatial distribution of normal direction are considered to calculate the complex permeability of magnetic flake materials.Its analytical model is derived from the Landau-Lifshitz- Gilbert equation and Bruggeman's effective medium theory.The calculated results agree well with the experiment.

  18. Non-Enzymatic Modification of Aminophospholipids by Carbonyl-Amine Reactions

    Directory of Open Access Journals (Sweden)

    Reinald Pamplona

    2013-02-01

    Full Text Available Non-enzymatic modification of aminophospholipids by lipid peroxidation-derived aldehydes and reducing sugars through carbonyl-amine reactions are thought to contribute to the age-related deterioration of cellular membranes and to the pathogenesis of diabetic complications. Much evidence demonstrates the modification of aminophospholipids by glycation, glycoxidation and lipoxidation reactions. Therefore, a number of early and advanced Maillard reaction-lipid products have been detected and quantified in different biological membranes. These modifications may be accumulated during aging and diabetes, introducing changes in cell membrane physico-chemical and biological properties.

  19. A green synthesis of α,β-unsaturated carbonyl compounds from glyceraldehyde acetonide

    Directory of Open Access Journals (Sweden)

    Cláudia O. Veloso

    2011-01-01

    Full Text Available The catalytic behavior of Cs-exchanged and Cs-impregnated zeolites (X and Y was studied using the Knoevenagel condensation between glyceraldehyde acetonide and ethyl acetoacetate in order to produce the corresponding α,β-unsaturated carbonyl compound that is an important intermediate for fine chemicals. The influence of reaction temperature, type of zeolite, and basicity of the sites on the catalytic behavior of the samples was evaluated. All zeolites were active for the studied reaction. The formation of the main condensation product was favored at lower reaction temperatures. Products of further condensations were also observed especially for samples that were only dried before catalytic test.

  20. Multiband microwave absorption films based on defective multiwalled carbon nanotubes added carbonyl iron/acrylic resin

    Energy Technology Data Exchange (ETDEWEB)

    Li Yong, E-mail: liyong1897@163.co [Institute of Naval Logistic Technology and Equipment of PLA, Beijing 100072 (China); Chen Changxin, E-mail: chen.c.x@sjtu.edu.c [National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Pan Xiaoyan [School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Ni Yuwei; Zhang Song; Huang, Jie [Institute of Naval Logistic Technology and Equipment of PLA, Beijing 100072 (China); Chen Da; Zhang Yafei [National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2009-05-01

    Defective multiwalled carbon nanotubes (MWCNTs) were introduced to the carbonyl iron (CI) based composites to improve its microwave absorption by a simple ultrasonic mixing process. The electromagnetic parameters were measured in the 2-18 GHz range. Microwave absorption of CI based composites with 2 mm in thickness was evidently enhanced by adding as little as 1.0 wt% defective MWCNTs with two well separated absorption peaks exceeding -20 dB, as compared with that of pure CI based and defective MWCNTs composites. The enhancement mechanism is thought due to the interaction and better electromagnetic match between defective MWCNTs and ferromagnetic CI particles.

  1. Elevated Levels of Carbonyl Compounds in the Atmosphere of Eastern Himalaya in India

    Science.gov (United States)

    Sarkar, C.; Chatterjee, A.; Majumdar, D.; Raha, S.; Ghosh, S. K.; Srivastava, A.

    2015-12-01

    A first ever study on atmospheric carbonyl compounds (CC) were made over eastern Himalaya in India. Samples were collected over a high altitude hill station, Darjeeling (27.01°N, 88.15°E, 2200 masl) during 2011-2012. It is well known that CC have toxic and carcinogenic properties as well as they have important effects on regional climate. Therefore their presence in the environment is of great concern especially for the Himalayan region because of the ecological and geographical importance of the area. The average annual concentration of total CCs was 293.3 ± 463.9 μgm-3 with maximum during post monsoon (1104.8 ± 568.0 μgm-3) and minimum during winter season (72.2 ± 42.9 μgm-3). Darjeeling experiences huge emissions of carbonaceous pollutants from massive influx of tourists during premonsoon and postmonsoon seasons. Though the emission strength could be comparable, the loss of carbonyls from the atmosphere could be due to photochemical degradation under high solar insolation during premonsoon. Acetone was most abundant species with an annual average concentration of 200.8±352.9 μgm-3 with 70 % contribution to the total CCs measured. Interestingly, acetone over Darjeeling was found to be much higher than most of the metropolitan cities in the world. The average formaldehyde to acetaldehyde ratio (1.64 ± 1.43) over Darjeeling is a good representation of a typical urban atmosphere at this high altitude over this part of Himalaya. High carbonyl concentration over eastern Himalaya compared to other megacities across the globe could be attributed to uncontrolled activities related to development in tourism, high population density and moreover it's unique orography and land use pattern with narrow roads, unplanned township etc. The unscientific treatment of human and animal and other domestic waste is another major concern which significantly contribute to carbonyl and other carbonaceous pollutants over this part of Himalaya.

  2. LASER-INDUCED DECOMPOSITION OF METAL CARBONYLS FOR CHEMICAL VAPOR DEPOSITION OF MICROSTRUCTURES

    OpenAIRE

    Tonneau, D.; Auvert, G.; Pauleau, Y.

    1989-01-01

    Tungsten and nickel carbonyls were used to produce metal microstructures by laser-induced chemical vapor deposition (CVD) on various substrates. The deposition rate of microstructures produced by thermodecomposition of W(CO)6 on Si substrates heated with a cw Ar+ laser beam was relatively low (10 to 30 nm/s) even at high temperatures (above 900°C). Ni microstructures were deposited on quartz substrates irradiated with a CO2 laser beam. Relatively high laser powers were needed to heat the Ni s...

  3. Carbonyl sulfide detection with a thermoelectrically cooled midinfrared quantum cascade laser

    Science.gov (United States)

    Roller, Chad; Kosterev, Anatoliy A.; Tittel, Frank K.; Uehara, Kiyoji; Gmachl, Claire; Sivco, Deborah L.

    2003-11-01

    A compact absorption spectrometer with a midinfrared tunable quantum cascade laser operating at 4.86 μm (2054 cm-1) is used to measure lower concentrations of carbonyl sulfide (COS) in air. A detection sensitivity of ~30 parts in 109 of COS and the selectivity of two stable isotopes, 12C16O32S and 12C16O34S, are demonstrated. Specifically, the feasibility of detecting COS in expired human breath as a potential noninvasive medical diagnostic tool is investigated.

  4. STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A BIDENTATE POLYMER BOUND CIS-DICARBONYLRHODIUM COMPLEX AS CATALYST

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaojun; LIU Zhongyang; PAN Pinglai; YUAN Guoqing

    1996-01-01

    Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.

  5. Determination of gaseous and particulate carbonyls (glycolaldehyde, hydroxyacetone, glyoxal, methylglyoxal, nonanal and decanal in the atmosphere at Mt. Tai

    Directory of Open Access Journals (Sweden)

    K. Kawamura

    2013-01-01

    Full Text Available Gaseous and particulate semi-volatile carbonyl compounds were determined every three hours in the atmosphere of Mount Tai (elevation, 1534 m in the North China Plain during 2–5, 23–24 and 25 June, 2006 under a clear sky condition. Using two-step filter cartridge in a series, particulate carbonyls were first collected on a quartz filter and then gaseous carbonyls were collected on a quartz filter impregnated with O-benzylhydroxylamine (BHA. After the two-step derivatization with BHA and N,O-bis(trimethylsilyltrifluoroacetamide (BSTFA, carbonyl derivatives were measured using a gas chromatography. The gaseous concentrations were obtained as follow: glycolaldehyde (range 0–1271 ng m−3, average 555 ng m−3, hydroxyacetone (0–707 ng m−3, 163 ng m−3, glyoxal (198–1396 ng m−3, 720 ng m−3, methylglyoxal (410–3170 ng m−3, 1376 ng m−3, n-nonanal (0–236 ng m−3, 71 ng m−3, and n-decanal (0–159 ng m−3, 31 ng m−3. These concentrations are among the highest ever reported in the urban and forest atmosphere. We found that gaseous carbonyls are more than 10 times more abundant than particulate carbonyls. Time-resolved variations of carbonyls did not show any a clear diurnal pattern, except for hydroxyacetone. We found that glyoxal, methylglyoxal and glycolaldehyde positively correlated with levoglucosan (a tracer of biomass burning, suggesting that a contribution from field burning of agricultural wastes (wheat crops is significant for the bifunctional carbonyls in the atmosphere of Mt. Tai. Upward transport of the pollutants to the mountaintop from the low lands in the North China Plain is a major process to control the distributions of carbonyls in the upper atmosphere over Mt. Tai.

  6. Cytoprotective Effects of Hydrophilic and Lipophilic Extracts of Pistacia vera against Oxidative Versus Carbonyl Stress in Rat Hepatocytes.

    Science.gov (United States)

    Shahraki, Jafar; Zareh, Mona; Kamalinejad, Mohammad; Pourahmad, Jalal

    2014-01-01

    This study was conducted to evaluate the cytoprotection of various extracts and bioactive compounds found in Pistacia vera againts cytotoxicity, ROS formation, lipid peroxidation, protein carbonylation, mitochondrial and lysosomal membrane damages in cell toxicity models of diabetes related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, water and ethyl acetate were used to prepare crude pistachios extracts, which were then used to screen for in-vitro cytoprotection of freshly isolated rat hepatocytes against these toxins. The order of protection by Pistacia vera extracts against both hydroperoxide induced oxidative stress (ROS formation) and glyoxal induced protein carbonylation was: pistachio methanolic extract >pistachio water extract, gallic acid, catechin> α-tochoferol and pistachio ethyl acetate extract. Finally due to higher protection achieved by methanolic extract even compared to sole pretreatment of gallic acid, catechin or α-tochoferol, we suggest that cytoprotection depends on the variety of polar and non-polar compounds found in methanolic extract, it is likely that multiple cytoprotective mechanisms are acting against oxidative and carbonyl induced cytotoxicity. To our knowledge, we are the first to report the cytoprotective activity of Pistacia vera extracts against oxidative and carbonyl stress seen in type 2 diabetes hepatocytes model. PMID:25587316

  7. Engineered Trx2p industrial yeast strain protects glycolysis and fermentation proteins from oxidative carbonylation during biomass propagation

    Directory of Open Access Journals (Sweden)

    Gómez-Pastor Rocío

    2012-01-01

    Full Text Available Abstract Background In the yeast biomass production process, protein carbonylation has severe adverse effects since it diminishes biomass yield and profitability of industrial production plants. However, this significant detriment of yeast performance can be alleviated by increasing thioredoxins levels. Thioredoxins are important antioxidant defenses implicated in many functions in cells, and their primordial functions include scavenging of reactive oxygen species that produce dramatic and irreversible alterations such as protein carbonylation. Results In this work we have found several proteins specifically protected by yeast Thioredoxin 2 (Trx2p. Bidimensional electrophoresis and carbonylated protein identification from TRX-deficient and TRX-overexpressing cells revealed that glycolysis and fermentation-related proteins are specific targets of Trx2p protection. Indeed, the TRX2 overexpressing strain presented increased activity of the central carbon metabolism enzymes. Interestingly, Trx2p specifically preserved alcohol dehydrogenase I (Adh1p from carbonylation, decreased oligomer aggregates and increased its enzymatic activity. Conclusions The identified proteins suggest that the fermentative capacity detriment observed under industrial conditions in T73 wine commercial strain results from the oxidative carbonylation of specific glycolytic and fermentation enzymes. Indeed, increased thioredoxin levels enhance the performance of key fermentation enzymes such as Adh1p, which consequently increases fermentative capacity.

  8. Inhibition of Listeria monocytogenes on cooked cured chicken breasts by acidified coating containing allyl isothiocyanate or deodorized Oriental mustard extract.

    Science.gov (United States)

    Olaimat, Amin N; Holley, Richard A

    2016-08-01

    Ready-to-eat meats are considered foods at high risk to cause life-threatening Listeria monocytogenes infections. This study screened 5 L. monocytogenes strains for their ability to hydrolyze sinigrin (a glucosinolate in Oriental mustard), which formed allyl isothiocyanate (AITC) and reduced L. monocytogenes viability on inoculated vacuum-packed, cooked, cured roast chicken slices at 4 °C. Tests involved incorporation of 25-50 μl/g AITC directly or 100-250 mg/g Oriental mustard extract in 0.5% (w/v) κ-carrageenan/2% (w/v) chitosan-based coatings prepared using 1.5% malic or acetic acid. L. monocytogenes strains hydrolyzed 33.6%-48.4% pure sinigrin in MH broth by 21 d at 25 °C. Acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 100-250 mg/g mustard reduced the viability of L. monocytogenes and aerobic bacteria on cooked, cured roast chicken slices by 4.1 to >7.0 log10 CFU/g compared to uncoated chicken stored at 4 °C for 70 d. Coatings containing malic acid were significantly more antimicrobial than those with acetic acid. During storage for 70 d, acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 250 mg/g mustard extract reduced lactic acid bacteria (LAB) numbers 3.8 to 5.4 log10 CFU/g on chicken slices compared to uncoated samples. Acidified κ-carrageenan/chitosan-based coatings containing either AITC or Oriental mustard extract at the concentrations tested had the ability to control L. monocytogenes viability and delay growth of potential spoilage bacteria on refrigerated, vacuum-packed cured roast chicken. PMID:27052706

  9. Synthesis and structural characterization of [eta superscript 3]-allyl([alpha]-diimine)nickel(II) complexes bearing trimethylsilyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Ionkin, Alex S.; Marshall, William J. (Dupont)

    2012-02-10

    A set of isomeric para- and meta-trimethylsilylphenyl ortho-substituted N,N-phenyl {alpha}-diimine ligands [(Ar-N C(Me)-(Me)C N-Ar) Ar=2,6-di(4-trimethylsilylphenyl)phenyl (16); Ar=2,6-di(3-trimethylsilylphenyl)phenyl (17)] have been synthesized through a two-step procedure. The palladium-catalyzed cross-coupling reaction between 2,6-dibromophenylamine (7) and 4-trimethylsilylphenylboronic acid (8), 3-trimethylsilylphenylboronic acid (9) was used to prepare 4,4-bis(trimethylsilyl)-[1,1;3,1]terphenyl-2-ylamine (10) and 3,3-bis(trimethylsilyl)-[1,1;3,1]terphenyl-2-ylamine (11). The di-1-adamantylphosphine oxide Ad{sub 2}P(O)H (13) and di-tert-butyl-trimethylsilylanylmethylphosphine tert-Bu{sub 2}P-CH{sub 2}-SiMe{sub 3} (14) were used for the first time as ligands for the Suzuki coupling. The condensation of 2,2,3,3-tetramethoxybutane (15) with anilines 10 and 11 afforded {alpha}-diimines 16 and 17. The reaction of {pi}-allylnickel chloride dimer (18), {alpha}-diimines (16), (17) and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BAF) (19) or silver hexafluoroantimonate (20) led to two sets of isomeric complexes [{eta}{sup 3}-allyl(Ar-N C(Me)-(Me)C N-Ar)Ni]{sup +} X{sup -}, [Ar=2,6-di(4-trimethylsilylphenyl)phenyl, X=BAF (3), X=SbF6 (4); Ar=2,6-di(3-trimethylsilylphenyl)phenyl, X=BAF (5), X=SbF6 (6)]. The steric repulsion of closely positioned trimethylsilyl groups in 4 caused the distortion of the nickel square planar coordination by 17.6{sup o} according to X-ray analysis.

  10. Structural analysis by reductive cleavage with LiAlH4 of an allyl ether choline-phospholipid, archaetidylcholine, from the hyperthermophilic methanoarchaeon Methanopyrus kandleri

    Directory of Open Access Journals (Sweden)

    Masateru Nishihara

    2002-01-01

    Full Text Available A choline-containing phospholipid (PL-4 in Methanopyrus kandleri cells was identified as archaetidylcholine, which has been described by Sprott et al. (1997. The PL-4 consisted of a variety of molecular species differing in hydrocarbon composition. Most of the PL-4 was acid-labile because of its allyl ether bond. The identity of PL-4 was confirmed by thin-layer chromatography (TLC followed by positive staining with Dragendorff-reagent and fast-atom bombardment–mass spectrometry. A new method of LiAlH4 hydrogenolysis was developed to cleave allyl ether bonds and recover the corresponding hydrocarbons. We confirmed the validity of the LiAlH4 method in a study of the model compound synthetic unsaturated archaetidic acid (2,3-di-O-geranylgeranyl-sn-glycerol-1-phosphate. Saturated ether bonds were not cleaved by the LiAlH4 method. The hydrocarbons formed following LiAlH4 hydrogenolysis of PL-4 were identified by gas–liquid chromatography and mass spectrometry. Four kinds of hydrocarbons with one to four double bonds were detected: 47% of the hydrocarbons had four double bonds; 11% had three double bonds; 14% had two double bonds; 7% had one double bond; and 6% were saturated species. The molecular species composition of PL-4 was also estimated based on acid lability: 77% of the molecular species had two acid-labile hydrocarbons; 11% had one acid-labile and one acid-stable hydrocarbon; and 11% had two acid-stable hydrocarbons. To our knowledge, this is the first report of a specific chemical degradation method for the structural analysis of allyl ether phospholipid in archaea.

  11. Substrate and stereocontrolled iodocycloetherification of highly functionalized enantiomerically pure allylic alcohols: application to synthesis of cytotoxic 2-epi jaspine B and its biological evaluation.

    Science.gov (United States)

    Kundooru, Somireddy; Das, Pintu; Meena, Sanjeev; Kumar, Vikash; Siddiqi, Mohammad Imran; Datta, Dipak; Shaw, Arun K

    2015-08-14

    Stereoselectivities of electrophilic additions of molecular iodine to enantiomerically pure highly functionalized allylic alcohols with internal nucleophiles have been investigated. The intramolecular nucleophilic attack on the I2-π complex by an oxygen nucleophile to obtain tri- and tetrasubstituted THFs is highly regio-, stereoselective and substrate controlled. The application of this study has been shown by utilizing one of the THFs 4a as a key intermediate to complete the total synthesis of marine anti-cancer natural product 2-epi jaspine B. PMID:26133669

  12. Synthesis of oxacyclic scaffolds via dual ruthenium hydride/Brønsted acid-catalyzed isomerization/cyclization of allylic ethers.

    Science.gov (United States)

    Ascic, Erhad; Ohm, Ragnhild G; Petersen, Rico; Hansen, Mette R; Hansen, Casper L; Madsen, Daniel; Tanner, David; Nielsen, Thomas E

    2014-03-17

    A ruthenium hydride/Brønsted acid-catalyzed tandem sequence is reported for the synthesis of 1,3,4,9-tetrahydropyrano[3,4-b]indoles (THPIs) and related oxacyclic scaffolds. The process was designed on the premise that readily available allylic ethers would undergo sequential isomerization, first to enol ethers (Ru catalysis), then to oxocarbenium ions (Brønsted acid catalysis) amenable to endo cyclization with tethered nucleophiles. This methodology provides not only an attractive alternative to the traditional oxa-Pictet-Spengler reaction for the synthesis of THPIs, but also convenient access to THPI congeners and other important oxacycles such as acetals. PMID:24616060

  13. Effective production of S-allyl-L-cysteine through a homogeneous reaction with activated endogenous γ-glutamyltranspeptidase in garlic (Allium Sativum)

    OpenAIRE

    Xu, Xiaobian; Miao, Yelian; Chen, Jie Yu; Zhang, Qimei; Wang, Jining

    2013-01-01

    S-allyl-L-cysteine (SAC) is a bioactive compound in garlic (Allium sativum). A novel process including soaking and homogeneous reaction was applied for the effective production of SAC with endogenous γ-glutamyltranspeptidase (γ-GTP, EC 2.3.2.2) in garlic. The effects of temperature and CaCl2 concentration on γ-GTP activity in soaking, and the relationship of SAC production with γ-GTP activity in homogeneous reaction were investigated, using fresh garlic as raw material. The experimental resul...

  14. Synthesis of functionalized 5-substituted thiazolidine-2-thiones via adscititious xanthate-promoted radical cyclization of allyl(alkyl/aryl)dithiocarbamates.

    Science.gov (United States)

    Gao, Simiao; Zhang, Yu; Dong, Jun; Chen, Ning; Xu, Jiaxi

    2016-01-21

    Functionalized 5-substituted thiazolidine-2-thiones were synthesized efficiently from alkyl allyl(alkyl/aryl)-dithiocarbamates via radical cyclization with the corresponding S-alkyl O-ethyl xanthates as the adscititious radical precursors. The application of the adscititious radical precursors improves not only the yields, but also the efficiency in the radical cyclization reaction significantly. The current adscititious radical precursor method provides a new strategy for the achievement and improvement of some radical reactions which are hardly or difficultly realized by the traditional direct methods. PMID:26626401

  15. α-Allyl-ω-Methoxy-polyethylenglykol-co-maleat-basierte Polycarboxylat-Fließmittel für ultra-hochfesten Beton (UHPC): Synthese, Eigenschaften, Wirkmechanismus und Funktionalisierung

    OpenAIRE

    Gruber, Mirko

    2010-01-01

    Polycarboxylat-Fließmittel auf Basis von α-Allyl-ω-Methoxypolyethylenglykol-co-maleat wurden hinsichtlich Ankergruppe und Seitenkette chemisch so modifiziert, dass eine optimale Verflüssigung von ultra-hochfestem Beton erzielt wurde. Ergänzend wurde ein Scale-up dieser hocheffizienten Polymere von Labor- in den technischen 20L-Maßstab durchgeführt. Eine weitere Effektivitätssteigerung dieser Fließmittel wurde durch Kombination mit synergistisch wirkenden α-Hydroxycarbonsäuresalzen erzielt. Ei...

  16. (4R-4-(2-Allyl-2H-1,2,3-triazol-4-yl-1,2-O-isopropylidene-l-threose

    Directory of Open Access Journals (Sweden)

    David J. Watkin

    2008-12-01

    Full Text Available X-ray crystallography unequivocally confirmed the structure of the title compound, C12H17N3O4, as (4R-4-(2-allyl-2H-1,2,3-triazol-4-yl-1,2-O-isopropylidene-l-threose. The absolute configuration was determined by the use of d-glucorono-3,6-lactone as the starting material. The crystal structure consists of hydrogen-bonded chains of molecules running parallel to the a axis. There are no unusual packing features.

  17. CO dissociation on Ni: The effect of steps and of nickel carbonyl

    DEFF Research Database (Denmark)

    Engbæk, Jakob; Lytken, Ole; Nielsen, Jane Hvolbæk;

    2008-01-01

    The dissociation of CO was investigated on a stepped Ni(141313) crystal. The experiments show that the monoatomic steps completely dominate the dissociation of CO on the nickel surface. The activation energy for dissociation of CO along the steps is measured at 500 K to be 150 kJ/mol in the press......The dissociation of CO was investigated on a stepped Ni(141313) crystal. The experiments show that the monoatomic steps completely dominate the dissociation of CO on the nickel surface. The activation energy for dissociation of CO along the steps is measured at 500 K to be 150 k......J/mol in the pressure range 1-7 X 10(-6) mbar CO. Poisoning the steps by preadsorbing 0.05 ML sulfur, the dissociation rate was reduced by more than a factor of 50 clearly providing evidence for the step activity. Furthermore, by deliberately adding remote amounts of nickel carbonyl (0.25%) to the CO gas, it is shown...... that the dissociation probability of CO is increased by a factor of 60 compared to when using a purified CO gas. This clearly demonstrates the importance of avoiding nickel carbonyl when CO dissociation is studied. CO dissociation is important because it is believed to be the rate limiting step in methanation...

  18. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyu, E-mail: wanghongyu07010310@163.com; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-11-01

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2–12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below −10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI. - Highlights: • The Co-coated carbonyl iron Co(CI) particles were prepared by electroless plating. • The electromagnetic wave absorbing properties of Co(CI) particles were studied. • The heat treatment on the absorbing property of Co(CI) particles was studied. • The Co(CI) particles have good absorbing property when compared with CI.

  19. Impact of silica-coating on the microwave absorption properties of carbonyl iron powder

    International Nuclear Information System (INIS)

    Microwave absorption properties, especially the band width and depth of reflection loss are highlighted as key measurement in studies of microwave absorber. In order to improve the band width and depth of reflection loss of carbonyl iron powder (CIP), we prepared SiO2 layers on the surface of CIP by using tetraethyl orthosilicate (TEOS) as a SiO2 source and 3-aminopropyl triethoxysilane (APTES) as a surface modifier. SiO2 layer was formed by the hydrolysis of TEOS. The results show that after treatment the CIP is covered by a 5–10 nm coating layer. Contrast to uncoated samples, coated samples show improved absorption properties. The minimum of reflection loss is −38.8 dB at 11 GHz and the band width of reflection loss exceeding −10 dB is from 8 GHz to 14 GHz. - Highlights: • Silica coatings were prepared on the surface of carbonyl iron powder. • Coating layers were identified by several ways. • We discussed the absorbing mechanism of coated samples. • Reflection loss was significantly improved, the width of RL exceeding −10 dB is from 8 GHz to 14 GHz

  20. Analysis of the carbonyl group stretching vibrations in some structural fragments of poly-3-hydroxybutyrate

    CERN Document Server

    Pitsevich, George A; Doroshenko, Iryna

    2016-01-01

    The structure and the medium effects exerted on the spectral characteristics of the carbonyl group stretching vibrations in some structural fragments of poly-3-hydroxybutyrate have been analyzed. Calculations of the equilibrium configurations and IR spectra were carried out using the Gaussian program set in the approximation B3LYP/cc-pVDZ. It has been shown that typical bending of the poly-3-hydroxybutyrate chain is observed with an increase in the number of structural units. In order to explain the difference between the calculated and experimental frequencies of the C=O group stretching vibrations, the calculations of the potential energy curve associated with variations in the length of C=O bond and the subsequent numerical solution of a one-dimensional vibrational Schr\\"odinger equation have been performed. The medium effects have been taken into account within the scope of a polarizable continuum model. Owing to the inclusion of the above-mentioned factors, which affect frequencies of the carbonyl groups...