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Sample records for intermediates alkylated products

  1. Improved enzymatic production of phenolated glycerides through alkyl phenolate intermediate

    DEFF Research Database (Denmark)

    Yang, Zhiyong; Feddern, Vivian; Glasius, Marianne

    2011-01-01

    This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl dihydroc...

  2. REACTIONS OF PEROXYNITRITE WITH URIC ACID: FORMATION OF REACTIVE INTERMEDIATES, ALKYLATED PRODUCTS AND TRIURET, AND IN VIVO PRODUCTION OF TRIURET UNDER CONDITIONS OF OXIDATIVE STRESS

    Science.gov (United States)

    Gersch, Christine; Palii, Sergiu P.; Imaram, Witcha; Kim, Kyung Mee; Karumanchi, S. Ananth; Angerhofer, Alexander; Johnson, Richard J.; Henderson, George N.

    2009-01-01

    Hyperuricemia is associated with hypertension, metabolic syndrome, preeclampsia, cardiovascular disease and renal disease, all conditions associated with oxidative stress. We hypothesized that uric acid, a known antioxidant, might become prooxidative following its reaction with oxidants; and, thereby contribute to the pathogenesis of these diseases. Uric acid and 1,3-15N2-uric acid were reacted with peroxynitrite in different buffers and in the presence of alcohols, antioxidants and in human plasma. The reaction products were identified using liquid chromatography-mass spectrometry (LC-MS) analyses. The reactions generate reactive intermediates that yielded triuret as their final product. We also found that the antioxidant, ascorbate, could partially prevent this reaction. Whereas triuret was preferentially generated by the reactions in aqueous buffers, when uric acid or 1,3-15N2-uric acid was reacted with peroxynitrite in the presence of alcohols, it yielded alkylated alcohols as the final product. By extension, this reaction can alkylate other biomolecules containing OH groups and others containing labile hydrogens. Triuret was also found to be elevated in the urine of subjects with preeclampsia, a pregnancy-specific hypertensive syndrome that is associated with oxidative stress, whereas very little triuret is produced in normal healthy volunteers. We conclude that under conditions of oxidative stress, uric acid can form reactive intermediates, including potential alkylating species, by reacting with peroxynitrite. These reactive intermediates could possibly explain how uric acid contributes to the pathogenesis of diseases such as the metabolic syndrome and hypertension. PMID:19219741

  3. Reduction and alkylation of peanut allergen isoforms Ara h 2 and Ara h 6; characterization of intermediate- and end products.

    Science.gov (United States)

    Apostolovic, Danijela; Luykx, Dion; Warmenhoven, Hans; Verbart, Dennis; Stanic-Vucinic, Dragana; de Jong, Govardus A H; Velickovic, Tanja Cirkovic; Koppelman, Stef J

    2013-12-01

    Conglutins, the major peanut allergens, Ara h 2 and Ara h 6, are highly structured proteins stabilized by multiple disulfide bridges and are stable towards heat-denaturation and digestion. We sought a way to reduce their potent allergenicity in view of the development of immunotherapy for peanut allergy. Isoforms of conglutin were purified, reduced with dithiothreitol and subsequently alkylated with iodoacetamide. The effect of this modification was assessed on protein folding and IgE-binding. We found that all disulfide bridges were reduced and alkylated. As a result, the secondary structure lost α-helix and gained some β-structure content, and the tertiary structure stability was reduced. On a functional level, the modification led to a strongly decreased IgE-binding. Using conditions for limited reduction and alkylation, partially reduced and alkylated proteins were found with rearranged disulfide bridges and, in some cases, intermolecular cross-links were found. Peptide mass finger printing was applied to control progress of the modification reaction and to map novel disulfide bonds. There was no preference for the order in which disulfides were reduced, and disulfide rearrangement occurred in a non-specific way. Only minor differences in kinetics of reduction and alkylation were found between the different conglutin isoforms. We conclude that the peanut conglutins Ara h 2 and Ara h 6 can be chemically modified by reduction and alkylation, such that they substantially unfold and that their allergenic potency decreases. © 2013.

  4. Amino acid nitrosation products as alkylating agents.

    Science.gov (United States)

    García-Santos, M del P; Calle, E; Casado, J

    2001-08-08

    Nitrosation reactions of alpha-, beta-, and gamma-amino acids whose reaction products can act as alkylating agents of DNA were investigated. To approach in vivo conditions for the two-step mechanism (nitrosation and alkylation), nitrosation reactions were carried out in aqueous acid conditions (mimicking the conditions of the stomach lumen) while the alkylating potential of the nitrosation products was investigated at neutral pH, as in the stomach lining cells into which such products can diffuse. These conclusions were drawn: (i) The alkylating species resulting from the nitrosation of amino acids with an -NH(2) group are the corresponding lactones; (ii) the sequence of alkylating power is: alpha-lactones > beta-lactones > gamma-lactones, coming respectively from the nitrosation of alpha-, beta-, and gamma-amino acids; and (iii) the results obtained may be useful in predicting the mutagenic effectiveness of the nitrosation products of amino acids.

  5. Intermediate inputs and economic productivity.

    Science.gov (United States)

    Baptist, Simon; Hepburn, Cameron

    2013-03-13

    Many models of economic growth exclude materials, energy and other intermediate inputs from the production function. Growing environmental pressures and resource prices suggest that this may be increasingly inappropriate. This paper explores the relationship between intermediate input intensity, productivity and national accounts using a panel dataset of manufacturing subsectors in the USA over 47 years. The first contribution is to identify sectoral production functions that incorporate intermediate inputs, while allowing for heterogeneity in both technology and productivity. The second contribution is that the paper finds a negative correlation between intermediate input intensity and total factor productivity (TFP)--sectors that are less intensive in their use of intermediate inputs have higher productivity. This finding is replicated at the firm level. We propose tentative hypotheses to explain this association, but testing and further disaggregation of intermediate inputs is left for further work. Further work could also explore more directly the relationship between material inputs and economic growth--given the high proportion of materials in intermediate inputs, the results in this paper are suggestive of further work on material efficiency. Depending upon the nature of the mechanism linking a reduction in intermediate input intensity to an increase in TFP, the implications could be significant. A third contribution is to suggest that an empirical bias in productivity, as measured in national accounts, may arise due to the exclusion of intermediate inputs. Current conventions of measuring productivity in national accounts may overstate the productivity of resource-intensive sectors relative to other sectors.

  6. Catalytic Gas-Phase Production of Lactide from Renewable Alkyl Lactates.

    Science.gov (United States)

    De Clercq, Rik; Dusselier, Michiel; Makshina, Ekaterina; Sels, Bert F

    2018-03-12

    A new route to lactide, which is a key building block of the bioplastic polylactic acid, is proposed involving a continuous catalytic gas-phase transesterification of renewable alkyl lactates in a scalable fixed-bed setup. Supported TiO 2 /SiO 2 catalysts are highly selective to lactide, with only minimal lactide racemization. The solvent-free process allows for easy product separation and recycling of unconverted alkyl lactates and recyclable lactyl intermediates. The catalytic activity of TiO 2 /SiO 2 catalysts was strongly correlated to their optical properties by DR UV/Vis spectroscopy. Catalysts with high band-gap energy of the supported TiO 2 phase, indicative of a high surface spreading of isolated Ti centers, show the highest turnover frequency per Ti site. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Kinetic and mechanistic studies of reactive intermediates in photochemical and transition metal-assisted oxidation, decarboxylation and alkyl transfer reactions

    Science.gov (United States)

    Carraher, Jack McCaslin

    Reactive species like high-valent metal-oxo complexes and carbon and oxygen centered radicals are important intermediates in enzymatic systems, atmospheric chemistry, and industrial processes. Understanding the pathways by which these intermediates form, their relative reactivity, and their fate after reactions is of the utmost importance. Herein are described the mechanistic detail for the generation of several reactive intermediates, synthesis of precursors, characterization of precursors, and methods to direct the chemistry to more desirable outcomes yielding 'greener' sources of commodity chemicals and fuels. High-valent Chromium from Hydroperoxido-Chromium(III). The decomposition of pentaaquahydroperoxido chromium(III) ion (hereafter Cr aqOOH2+) in acidic aqueous solutions is kinetically complex and generates mixtures of products (Craq3+, HCrO 4-, H2O2, and O2). The yield of high-valent chromium products (known carcinogens) increased from a few percent at pH 1 to 70 % at pH 5.5 (near biological pH). Yields of H 2O2 increased with acid concentration. The reproducibility of the kinetic data was poor, but became simplified in the presence of H2O2 or 2,2‧-azinobis(3-ethylbenzothiazoline-6-sulfonate) dianion (ABTS2-). Both are capable of scavenging strongly oxidizing intermediates). The observed rate constants (pH 1, [O2] ≤ 0.03 mM) in the presence of these scavengers are independent of [scavenger] and within the error are the same (k,ABTS2- = (4.9 +/- 0.2) x 10-4 s-1 and kH2O2 = (5.3 +/- 0.7) x 10-4 s-1); indicating involvement of the scavengers in post-rate determining steps. In the presence of either scavenger, decomposition of CrOOH2+ obeyed a two-term rate law, k obs / s-1 = (6.7 +/- 0.7) x 10-4 + (7.6 +/- 1.1) x 10-4 [H+]. Effect of [H+] on the kinetics and the product distribution, cleaner kinetics in the presence of scavengers, and independence of kobs on [scavenger] suggest a dual-pathway mechanism for the decay of Craq OOH2+. The H+-catalyzed path

  8. Separation of products of alkylation of isobutane by olefins

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.

    1979-03-15

    The alkylation (A1) of isobutane (I) by propylene, butylene and amylenes is carried out at 24-52 degrees, pressure sufficient to maintain the liquid phase, and a molar ratio of I to olefins (O1) 10:1-15:1. The bulk ratio of catalysts to hydrocarbons in the reaction zone was 0.5:1-10:1; when using HF-K-T as the catalysts, it should contain less than 5 percent water and greater than or equal to 65 percent titrated HF. The hydrocarbon products (UP) from the alkylation zone are added after separating the catalyst in a fractionation tower; distillation is carried out at 38-49 degrees and 1.03-1.3 NPa. The head fraction containing I and less than 50 molar percent C3H8 and also fraction I at the point below the input side of the UP which contains less than 8 molar percent C3H8 and fraction n-C4H10 at the point below the point of discharge of fraction I is drained from the tower. The alkylate is discharged at the bottom of the tower. According to the patent the tower operates at low pressure. This improves relative volatility of individual components and reduces heat consumption. The best results are obtained when a head fraction or the concentration C3H8 approximately 25 molar percent is discharged.

  9. Inhibitory Activities of Alkyl Syringates and Related Compounds on Aflatoxin Production.

    Science.gov (United States)

    Furukawa, Tomohiro; Iimura, Kurin; Kimura, Taichi; Yamamoto, Toshiyoshi; Sakuda, Shohei

    2016-06-07

    Inhibitors of aflatoxin production of aflatoxigenic fungi are useful for preventing aflatoxin contamination in crops. As methyl syringate weakly inhibits aflatoxin production, aflatoxin production inhibitory activities of additional alkyl syringates with alkyl chains from ethyl to octyl were examined. Inhibitory activity toward aflatoxin production of Aspergillus flavus became stronger as the length of the alkyl chains on the esters became longer. Pentyl, hexyl, heptyl, and octyl syringates showed strong activity at 0.05 mM. Heptyl and octyl parabens, and octyl gallate also inhibited aflatoxin production as strongly as octyl syringate. Alkyl parabens and alkyl gallates inhibit the complex II activity of the mitochondrial respiration chain; thus, whether alkyl syringates inhibit complex II activity was examined. Inhibitory activities of alkyl syringates toward complex II also became stronger as the length of the alkyl chains increased. The complex II inhibitory activity of octyl syringate was comparable to that of octyl paraben and octyl gallate. These results suggest that alkyl syringates, alkyl parabens, and alkyl gallates, including commonly used food additives, are useful for aflatoxin control.

  10. Inhibitory Activities of Alkyl Syringates and Related Compounds on Aflatoxin Production

    Directory of Open Access Journals (Sweden)

    Tomohiro Furukawa

    2016-06-01

    Full Text Available Inhibitors of aflatoxin production of aflatoxigenic fungi are useful for preventing aflatoxin contamination in crops. As methyl syringate weakly inhibits aflatoxin production, aflatoxin production inhibitory activities of additional alkyl syringates with alkyl chains from ethyl to octyl were examined. Inhibitory activity toward aflatoxin production of Aspergillus flavus became stronger as the length of the alkyl chains on the esters became longer. Pentyl, hexyl, heptyl, and octyl syringates showed strong activity at 0.05 mM. Heptyl and octyl parabens, and octyl gallate also inhibited aflatoxin production as strongly as octyl syringate. Alkyl parabens and alkyl gallates inhibit the complex II activity of the mitochondrial respiration chain; thus, whether alkyl syringates inhibit complex II activity was examined. Inhibitory activities of alkyl syringates toward complex II also became stronger as the length of the alkyl chains increased. The complex II inhibitory activity of octyl syringate was comparable to that of octyl paraben and octyl gallate. These results suggest that alkyl syringates, alkyl parabens, and alkyl gallates, including commonly used food additives, are useful for aflatoxin control.

  11. 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...

  12. Full-Scale Continuous Mini-Reactor Setup for Heterogeneous Grignard Alkylation of a Pharmaceutical Intermediate

    DEFF Research Database (Denmark)

    Pedersen, Michael Jønch; Holm, Thomas; Rahbek, Jesper P.

    2013-01-01

    A reactor setup consisting of two reactors in series has been implemented for a full-scale, heterogeneous Grignard alkylation. Solutions pass from a small filter reactor into a static mixer reactor with multiple side entries, thus combining continuous stirred tank reactor (CSTR) and plug flow...

  13. Photochemistry of phenyl alkyl ketones. The lifetime of the intermediate biradicals

    International Nuclear Information System (INIS)

    Small, R.D. Jr.; Scalano, J.C.

    1977-01-01

    The lifetimes of a number of biradicals produced in the photochemical Norrish type II reaction of phenyl alkyl ketones have been measured. The decay of the biradicals was followed by monitoring the competition with electron transfer to paraquat dications using nanosecond laser techniques. The lifetimes are rather insensitive to changes in temperature, substitution, and solvent, and are typically in the neighborhood of 100 ns. It is concluded that intersystem crossing is the main factor determining the biradical lifetimes. The rate constant for electron transfer to paraquat dications is 3.7 x 10 9 M -1 s -1 in methanol at room temperature for 1,4-ketyl--alkyl biradicals, and considerably higher for diketyl biradicals, apparently reflecting a change in path degeneracy. Oxygen behaves as a biradical scavenger with a rate constant of 6.2 x 10 9 M -1 s -1 in methanol. The lifetimes of the excited ketone triplets have also been determined at room temperature under the experimental conditions employed; this is an important parameter in determining the viability of the measurements of biradical lifetimes by this technique

  14. Neutral nickel oligo- and polymerization catalysts: the importance of alkyl phosphine intermediates in chain termination.

    Science.gov (United States)

    Heyndrickx, Wouter; Occhipinti, Giovanni; Minenkov, Yury; Jensen, Vidar R

    2011-12-16

    An unconventional chain termination reaction has been explored for the SHOP (Shell higher olefin process)-type, anilinotropone, and salicylaldiminato nickel-based oligo- and polymerization catalysts by using density functional theory (DFT). Starting from the tetracoordinate alkyl phosphine complex, the termination reaction was found to involve a rearrangement of the alkyl chain to form a pentacoordinate β-agostic complex, β-hydride elimination, and olefinic chain dissociation and to compete with propagation at sufficiently high phosphine concentration and/or basicity. It provides the first complete and convincing mechanistic rationale for the decreasing chain lengths observed upon increasing phosphine concentration and basicity. The unconventional reaction was found to be a major termination pathway for the SHOP-type catalyst and is very unlikely to lead to branching and olefin isomerization, which is critical for explaining why the SHOP catalyst, in contrast to the anilinotropone and salicylaldiminato catalysts, tends to lead to the oligomerization of ethylene to form linear α-olefins. Based on our results we have proposed a new and extended catalytic cycle for the SHOP-type ethylene oligomerization catalyst. Finally, the importance of the new termination reaction for the SHOP-type catalyst suggests that this reaction may also operate with other ethylene oligomerization nickel catalysts. This prediction was confirmed for a pyrazolonatophosphine catalyst, for which the new termination route was found to be even more facile, which explains the short oligomers produced by this catalyst. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Production of high-octane, unleaded motor fuel by alkylation of isobutane with isoamylenes obtained by dehydrogenation of isopentane

    Energy Technology Data Exchange (ETDEWEB)

    Hutson, T. Jr.; Hann, P.D.

    1981-01-31

    A process combination, with inter-cooperation, for producing high-octane alkylates comprising (a) dehydrogenating isopentane to isopentenes (amylenes), (b) introducing the mixture of said amylenes and unconverted isopentane into an HF alkylation unit for reaction with fresh or recycled isobutane, (c) separating the alkylation products into high octane alkylates, isopentane (for recycling to the dehydrogenation reactor) and isobutane (for recycling to the alkylation reactor).

  16. Fatty acid alkyl esters: perspectives for production of alternative biofuels.

    Science.gov (United States)

    Röttig, Annika; Wenning, Leonie; Bröker, Daniel; Steinbüchel, Alexander

    2010-02-01

    The global economy heads for a severe energy crisis: whereas the energy demand is going to rise, easily accessible sources of crude oil are expected to be depleted in only 10-20 years. Since a serious decline of oil supply and an associated collapse of the economy might be reality very soon, alternative energies and also biofuels that replace fossil fuels must be established. In addition, these alternatives should not further impair the environment and climate. About 90% of the biofuel market is currently captured by bioethanol and biodiesel. Biodiesel is composed of fatty acid alkyl esters (FAAE) and can be synthesized by chemical, enzymatic, or in vivo catalysis mainly from renewable resources. Biodiesel is already established as it is compatible with the existing fuel infrastructure, non-toxic, and has superior combustion characteristics than fossil diesel; and in 2008, the global production was 12.2 million tons. The biotechnological production of FAAE from low cost and abundant feedstocks like biomass will enable an appreciable substitution of petroleum diesel. To overcome high costs for immobilized enzymes, the in vivo synthesis of FAAE using bacteria represents a promising approach. This article points to the potential of different FAAE as alternative biofuels, e.g., by comparing their fuel properties. In addition to conventional production processes, this review presents natural and genetically engineered biological systems capable of in vivo FAAE synthesis.

  17. Intramolecular Schmidt reaction of acyl chlorides with alkyl azides: preparation of pyrrolizine by intramolecular capture of intermediates with alkenes or alkynes.

    Science.gov (United States)

    Wang, Bao-Juan; Xue, Ping; Gu, Peiming

    2015-02-11

    The preparation of substituted pyrrolizines through the Schmidt reaction of acyl chlorides with alkyl azides has been realized. Intramolecular capture of the isocyanate ion and N-acyliminium ion intermediates from the Schmidt process with alkene or alkyne units was achieved, and the efficiency of the conversion with respect to ring construction and bond formation was demonstrated.

  18. Intermediate product selection and blending in the food processing industry

    DEFF Research Database (Denmark)

    Kilic, Onur A.; Akkerman, Renzo; van Donk, Dirk Pieter

    2013-01-01

    This study addresses a capacitated intermediate product selection and blending problem typical for two-stage production systems in the food processing industry. The problem involves the selection of a set of intermediates and end-product recipes characterising how those selected intermediates...

  19. Alkylation of reticular polymers of ethynyl piperidol by alkyl halogen and investigation of the swelling of the products in water

    International Nuclear Information System (INIS)

    Khakimkhodjaev, S.N.; Khalikov, D.Kh.

    1999-01-01

    In the paper the results of investigation on alkylation of reticular polymer of ethyl piperidol by methyl Iodide and ethyl Iodide are adduced. It have been shown that in the first case the reaction of an alkylation proceeds up to 100% of a degree of completion. In the second case of an alkylation the highest degree of alkylation reaches only 60% which is connected with formation of secondary structures. In both cases the process of an alkylation results in deriving highly swelled system

  20. Enzymatic production of alkyl esters through alcoholysis: A critical evaluation of lipases and alcohols

    DEFF Research Database (Denmark)

    Li, Deng; Xu, Xuebing; Gudmundur G, Haraldsson

    2005-01-01

    This paper focuses on a detailed evaluation of commercially available immobilized lipases and simple monohydric alcohols for the production of alkyl esters from sunflower oil by enzymatic alcoholysis. Six lipases were tested with seven alcohols, including straight and branched-chain primary...... yield of FA alkyl esters, with yields well over 90% for methanol, absolute ethanol, and 1-propanol. Overall, 96% ethanol was the preferred alcohol for all lipases except Novozym 435, and ethanolysis reactions reached the maximal conversion efficiency. Increasing the water content in the system resulted...... commercial immobilized lipases are highly efficient and promising for the production of alkyl esters, offering high reaction yields and a simple operation process....

  1. Simultaneous determination of alkyl mesilates and alkyl besilates in finished drug products by direct injection GC/MS.

    Science.gov (United States)

    Wollein, Uwe; Schramek, Nicholas

    2012-01-23

    We report a specific, fast and feasible method for the simultaneous determination of methyl mesilate (MMS), ethyl mesilate (EMS), isopropyl mesilate (IMS), methyl besilate (MBS) and ethyl besilate (EBS) in finished drug products by GC/MS. Sample preparation was carried out by liquid extraction. The analytes were directly injected into the chromatographic system and quantified with the internal standard method using methyl tosylate (MTS) as internal standard (ISTD). The method gives excellent sensitivity for all the alkyl and aryl esters at typical target analyte level, according to the acceptance criteria that are described in the Guideline on the Limits of Genotoxic Impurities which has been issued in 2007 by the European Medicines Agency (EMA). The average recovery for methanesulfonic acid esters (mesilates) was not lower than 71%, for benzenesulfonic acid esters (besilates) not lower than 94%. A linear range with R² ≥ 0.9998 has been established for concentrations between 0.01 and 1.33 μg/ml. Validation of the method was carried out on a sample matrix containing MMS, EMS, IMS, MBS and EBS at relevant levels and was further confirmed on finished products containing APIs as mesilate salts (Bromocriptine mesilate, Doxazosin mesilate). Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Associated strangeness production at intermediate energies

    International Nuclear Information System (INIS)

    Saghai, B.

    1996-04-01

    Elementary strangeness production reactions with hadronic and electromagnetic probes are briefly reviewed. Some recent theoretical and experimental findings are underlined and a few open questions are singled out. (author)

  3. Production of alkyl-aromatics from light oxygenates over zeolite catalysts for bio-oil refining

    Science.gov (United States)

    Hoang, Trung Q.

    Upgrading of light oxygenates derived from biomass conversion, such as propanal and glycerol, to more valuable aromatics for biofuels has been demonstrated on zeolite catalysts. Aromatics with a high ratio of C 9/(C8+C7) and little benzene are produced at much higher yield from oxygenates than from olefins at mild conditions over HZSM-5. It is proposed that C9 aromatics are predominantly produced via acid-catalyzed aldol condensation. This reaction pathway is different from the pathway of propylene and other hydrocarbon aromatization that occurs via a hydrocarbon pool at more severe conditions with major aromatic products C6 and C7. In fact, investigation on the effect of crystallite size HZSM-5 has shown a higher ratio of C9/(C8+C 7) aromatics on small crystallite. This is due to faster removal of products from the shorter diffusion path length. As a result, a longer catalyst lifetime, less isomerization, and less cracking were observed on small crystallites. Beside crystallite size, pore geometry of zeolites was also found to significantly affect aromatic production for both conversion of propanal and glycerol. It is shown that the structure of the HZSM-22, with a one-dimensional and narrower channel system, restricts the formation of aromatics. In contrast, a higher yield of aromatic products is observed over HZSM-5 with its three-dimensional channel system. By increasing channel dimension and connectivity of the channels, increasing catalyst activity was also observed due to more accessible acid sites. It was also found that glycerol is highly active for dehydration on zeolites to produce high yields of acrolein (propenal), a high value chemical. To maximize aromatics from glycerol conversion, HZSM-5 and HY were found to be effective. A two-bed reactor of Pd/ZnO and HZSM-5 was used to first deoxygenate/hydrogenate glycerol over Pd/ZnO to intermediate oxygenates that can further aromatize on HZSM-5. The end results are very promising with significant improvement

  4. Production and signature of intermediate vector bosons

    International Nuclear Information System (INIS)

    Perrottet, M.

    1978-01-01

    The front-back asymmetriy of outgoing muons in the inclusive reaction pp-bar→Z (→μ + μ - )+ anything is calculated in the framework of the Drell--Yan model. We get very general expressions for the front-back asymmetry and the differential cross section in terms of the weak coupling constants and the parton distributions. Results for W +- production and proton-proton collisions are given. Numerical estimates are made using various parton distributions and the Weinberg-Salam model for definiteness. We comment on the predictions of gauge theories that accommodate the absence of parity violating effects in atomic physics. We also give a new estimate of the inclusive cross section pp-bar or pp→Z (→μ + μ - ) or W +- (→μ/sup plus-or-minusnu/μ)+ anything. The effects of asymptotic freedom in the front-back asymmetries and the total cross sections are investigated. We reanalyze results for the purely leptonic reaction e + e - →γ,Z→μ + μ -

  5. Kinetic and mechanistic studies of reactive intermediates in photochemical and transition metal-assisted oxidation, decarboxylation and alkyl transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Carraher, Jack McCaslin [Iowa State Univ., Ames, IA (United States)

    2014-01-01

    Reactive species like high-valent metal-oxo complexes and carbon and oxygen centered radicals are important intermediates in enzymatic systems, atmospheric chemistry, and industrial processes. Understanding the pathways by which these intermediates form, their relative reactivity, and their fate after reactions is of the utmost importance. Herein are described the mechanistic detail for the generation of several reactive intermediates, synthesis of precursors, characterization of precursors, and methods to direct the chemistry to more desirable outcomes yielding ‘greener’ sources of commodity chemicals and fuels.

  6. Direct-acting DNA alkylating agents present in aqueous extracts of areca nut and its products.

    Science.gov (United States)

    Hu, Chiung-Wen; Chao, Mu-Rong

    2012-11-19

    Areca nut is a carcinogen to humans and has been strongly associated with oral premalignant and malignant diseases. Previous studies speculated the presence of unknown direct-acting mutagens present in aqueous extracts of areca nut. We hypothesized whether any direct-acting alkylating agents are present in areca nut and its commercial products. In this study, calf thymus DNA was treated with four different aqueous extracts obtained from unripe and ripe areca nuts or their commercial products, namely, pan masala (without tobacco) and gutkha (with tobacco). Three N-alkylated purines including N7-methylguanine (N7-MeG), N3-methyladenine (N3-MeA), and N7-ethylguanine (N7-EtG) were detected using sensitive and specific isotope-dilution liquid chromatography-tandem-mass spectrometry (LC-MS/MS) methods. The results showed that four types of aqueous extracts significantly induced the formation of N7-MeG and N3-MeA in a linear dose-response manner. Extracts from unripe areca nut exhibited higher methylating potency than those of ripe areca nut, while gutkha had higher methylating potency than pan masala. Meanwhile, gutkha made with areca nut and tobacco, was the only extract found to induce the formation of N7-EtG. Overall, this study first demonstrated that the presence of direct-acting alkylating agents in areca nut and its commercial products exist at a level that is able to cause significant DNA damage. Our findings may provide another mechanistic rationale for areca nut-mediated oral carcinogenesis and also highlight the importance and necessity of the identification of these direct-acting alkylating agents.

  7. Alkylation base damage is converted into repairable double-strand breaks and complex intermediates in G2 cells lacking AP endonuclease.

    Directory of Open Access Journals (Sweden)

    Wenjian Ma

    2011-04-01

    Full Text Available DNA double-strand breaks (DSBs are potent sources of genome instability. While there is considerable genetic and molecular information about the disposition of direct DSBs and breaks that arise during replication, relatively little is known about DSBs derived during processing of single-strand lesions, especially for the case of single-strand breaks (SSBs with 3'-blocked termini generated in vivo. Using our recently developed assay for detecting end-processing at random DSBs in budding yeast, we show that single-strand lesions produced by the alkylating agent methyl methanesulfonate (MMS can generate DSBs in G2-arrested cells, i.e., S-phase independent. These derived DSBs were observed in apn1/2 endonuclease mutants and resulted from aborted base excision repair leading to 3' blocked single-strand breaks following the creation of abasic (AP sites. DSB formation was reduced by additional mutations that affect processing of AP sites including ntg1, ntg2, and, unexpectedly, ogg1, or by a lack of AP sites due to deletion of the MAG1 glycosylase gene. Similar to direct DSBs, the derived DSBs were subject to MRX (Mre11, Rad50, Xrs2-determined resection and relied upon the recombinational repair genes RAD51, RAD52, as well as on the MCD1 cohesin gene, for repair. In addition, we identified a novel DNA intermediate, detected as slow-moving chromosomal DNA (SMD in pulsed field electrophoresis gels shortly after MMS exposure in apn1/2 cells. The SMD requires nicked AP sites, but is independent of resection/recombination processes, suggesting that it is a novel structure generated during processing of 3'-blocked SSBs. Collectively, this study provides new insights into the potential consequences of alkylation base damage in vivo, including creation of novel structures as well as generation and repair of DSBs in nonreplicating cells.

  8. Production value optimization with intermediate jig product recirculation

    Directory of Open Access Journals (Sweden)

    Pielot Joachim

    2016-01-01

    Full Text Available The paper describes the result of the production value increase in systems with two and three jigs and recirculation of the interemediate product compared to the output value obtained from a single jig. The increase is greater when the reference ash content in the concentrate is lower.

  9. Ethanol Production from Different Intermediates of Sugar Beet Processing

    Directory of Open Access Journals (Sweden)

    Mladen Pavlečić

    2010-01-01

    Full Text Available In this investigation, the production of ethanol from the raw sugar beet juice and raw sugar beet cossettes has been studied. For ethanol production from the raw sugar beet juice, batch and fed-batch cultivation techniques in the stirred tank bioreactor were used, while batch ethanol production from the raw sugar beet cossettes was carried out in horizontal rotating tubular bioreactor (HRTB. In both cases, Saccharomyces cerevisiae was used as a production microorganism. During batch ethanol production from the raw sugar beet juice, ethanol yield was 59.89 g/L and production efficiency 78.8 %, and in fed-batch process the yield was 92.78 g/L and efficiency 93.4 %. At the same time, ethanol production in HRTB from the raw sugar beet cossettes with inoculum of 16.7 % V/m (raw sugar beet cossettes resulted in the highest ethanol yield of 54.53 g/L and production efficiency of 79.5 %. The obtained results clearly show that both intermediates of sugar beet processing can be successfully used for ethanol production.

  10. Thermodynamic analysis of fatty acid esterification for fatty acid alkyl esters production

    Energy Technology Data Exchange (ETDEWEB)

    Voll, Fernando A.P.; Cardozo-Filho, Lucio [Department of Chemical Engineering, Maringa State University (UEM), Maringa, PR, 87020-900 (Brazil); da Silva, Camila [Department of Chemical Engineering, Maringa State University (UEM), Maringa, PR, 87020-900 (Brazil); Department of Technology, Maringa State University (UEM), Umuarama, PR, 87506-370 (Brazil); Rossi, Carla C.R.S. [Department of Chemical Engineering, Maringa State University (UEM), Maringa, PR, 87020-900 (Brazil); College of Chemical Engineering, State University of Campinas (UNICAMP), Campinas, SP, 13083-970 (Brazil); Guirardello, Reginaldo [College of Chemical Engineering, State University of Campinas (UNICAMP), Campinas, SP, 13083-970 (Brazil); de Castilhos, Fernanda [Department of Chemical Engineering, Universidade Federal do Parana (UFPR), Curitiba, PR, 81531-990 (Brazil); Oliveira, J. Vladimir [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS, 99700-000 (Brazil)

    2011-02-15

    The development of renewable energy source alternatives has become a planet need because of the unavoidable fossil fuel scarcity and for that reason biodiesel production has attracted growing interest over the last decade. The reaction yield for obtaining fatty acid alkyl esters varies significantly according to the operating conditions such as temperature and the feed reactants ratio and thus investigation of the thermodynamics involved in such reactional systems may afford important knowledge on the effects of process variables on biodiesel production. The present work reports a thermodynamic analysis of fatty acid esterification reaction at low pressure. For this purpose, Gibbs free energy minimization was employed with UNIFAC and modified Wilson thermodynamic models through a nonlinear programming model implementation. The methodology employed is shown to reproduce the most relevant investigations involving experimental studies and thermodynamic analysis. (author)

  11. Thermodynamic analysis of fatty acid esterification for fatty acid alkyl esters production

    International Nuclear Information System (INIS)

    Voll, Fernando A.P.; Silva, Camila da; Rossi, Carla C.R.S.; Guirardello, Reginaldo; Castilhos, Fernanda de; Oliveira, J. Vladimir; Cardozo-Filho, Lucio

    2011-01-01

    The development of renewable energy source alternatives has become a planet need because of the unavoidable fossil fuel scarcity and for that reason biodiesel production has attracted growing interest over the last decade. The reaction yield for obtaining fatty acid alkyl esters varies significantly according to the operating conditions such as temperature and the feed reactants ratio and thus investigation of the thermodynamics involved in such reactional systems may afford important knowledge on the effects of process variables on biodiesel production. The present work reports a thermodynamic analysis of fatty acid esterification reaction at low pressure. For this purpose, Gibbs free energy minimization was employed with UNIFAC and modified Wilson thermodynamic models through a nonlinear programming model implementation. The methodology employed is shown to reproduce the most relevant investigations involving experimental studies and thermodynamic analysis.

  12. Production of n-alkyl lipids in living plants and implications for the geologic past

    Science.gov (United States)

    Diefendorf, Aaron F.; Freeman, Katherine H.; Wing, Scott L.; Graham, Heather V.

    2011-12-01

    Leaf waxes (i.e., n-alkyl lipids or n-alkanes) are land-plant biomarkers widely used to reconstruct changes in climate and the carbon isotopic composition of the atmosphere. There is little information available, however, on how the production of leaf waxes by different kinds of plants might influence the abundance and isotopic composition of n-alkanes in sedimentary archives. This lack of information increases uncertainty in interpreting n-alkyl lipid abundance and δ 13C signals in ancient settings. We provide here n-alkyl abundance distributions and carbon isotope fractionation data for deciduous and evergreen angiosperm and gymnosperm leaves from 46 tree species, representing 24 families. n-Alkane abundances are significantly higher in angiosperms than gymnosperms; many of the gymnosperm species investigated did not produce any n-alkanes. On average, deciduous angiosperms produce 200 times more n-alkanes than deciduous gymnosperms. Although differences between angiosperms and gymnosperms dominate the variance in n-alkane abundance, leaf life-span is also important, with higher n-alkane abundances in longer-lived leaves. n-Alkanol abundances covary with n-alkanes, but n-alkanoic acids have similar abundances across all plant groups. Isotopic fractionation between leaf tissue and individual alkanes ( ɛlipid) varies by as much as 10‰ among different chain lengths. Overall, ɛlipid values are slightly lower (-4.5‰) for angiosperm than for gymnosperm (-2.5‰) n-alkanes. Angiosperms commonly express slightly higher Δleaf (photosynthetic discrimination) relative to gymnosperms under similar growth conditions. As a result, angiosperm n-alkanes are expected to be generally 3-5‰ more depleted in 13C relative to gymnosperm alkanes for the same locality. Differences in n-alkane production indicate the biomarker record will largely (but not exclusively) reflect angiosperms if both groups were present, and also that evergreen plants will likely be overrepresented

  13. Characterization of alkyl phenols in cashew (Anacardium occidentale) products and assay of their antioxidant capacity.

    Science.gov (United States)

    Trevisan, M T S; Pfundstein, B; Haubner, R; Würtele, G; Spiegelhalder, B; Bartsch, H; Owen, R W

    2006-02-01

    In this study the content of anacardic acids, cardanols and cardols in cashew apple, nut (raw and roasted) and cashew nut shell liquid (CNSL) were analysed. The higher amounts (353.6 g/kg) of the major alkyl phenols, anacardic acids were detected in CNSL followed by cashew fibre 6.1 g/kg) while the lowest (0.65 g/kg) amounts were detected in roasted cashew nut. Cashew apple and fibre contained anacardic acids exclusively, whereas CNSL also contained an abundance of cardanols and cardols. Cashew nut (raw and roasted) also contained low amounts of hydroxy alkyl phenols. Cashew nut shell liquid was used for a basic fractionation of the alkyl phenol classes and the individual anacardic acids, major cardanols and cardols were purified to homogeneity from these fractions by semi-preparative HPLC and definitively identified by nano-ESI-MS-MS, GC-MS and NMR analyses. The hexane extracts (10 mg/ml) of all cashew products tested plus CNSL, displayed significant antioxidant capacity. Cashew nut shell liquid was the more efficient (inhibition=100%) followed by the hexane extract of cashew fibre (94%) and apple (53%). The antioxidant capacity correlated significantly (P4.0 mM). The data shows that of these substances, anacardic-1 was by far the more potent antioxidant (IC50=0.27 mM) compared to cardol-1 (IC50=1.71 mM) and cardanol-1 (IC50>4.0 mM). The antioxidant capacity of anacardic acid-1 is more related to inhibition of superoxide generation (IC50=0.04 mM) and xanthine oxidase (IC50=0.30 mM) than to scavenging of hydroxyl radicals. At present a substantial amount of cashew fibre is mostly used in formulations of animal or poultry feeds. The data presented in this study, indicates that this waste product along with CNSL, both of which contain high contents of anacardic acids, could be better utilized in functional food formulations and may represent a cheap source of cancer chemopreventive agents.

  14. Dual platinum and pyrrolidine catalysis in the direct alkylation of allylic alcohols: selective synthesis of monoallylation products.

    Science.gov (United States)

    Shibuya, Ryozo; Lin, Lu; Nakahara, Yasuhito; Mashima, Kazushi; Ohshima, Takashi

    2014-04-22

    A dual platinum- and pyrrolidine-catalyzed direct allylic alkylation of allylic alcohols with various active methylene compounds to produce products with high monoallylation selectivity was developed. The use of pyrrolidine and acetic acid was essential, not only for preventing undesirable side reactions, but also for obtaining high monoallylation selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 40 CFR 721.9220 - Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric...

    Science.gov (United States)

    2010-07-01

    ... amines with a substituted benzenesulfonic acid and sulfuric acid (generic name). 721.9220 Section 721... Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric acid... benzenesulfonic acid and sulfuric acid (PMNs P-89-703, P-89-755, and P-89-756) are subject to reporting under this...

  16. Evidence for the Inhibition by Temozolomide, an Imidazotetrazine Family Alkylator, of Intermediate-Conductance Ca2+-Activated K+ Channels in Glioma Cells

    Directory of Open Access Journals (Sweden)

    Poh-Shiow Yeh

    2016-05-01

    Full Text Available Background: Temozolomide (TMZ, an oral alkylator of the imidazotetrazine family, is used to treat glioma. Whether this drug has any ionic effects in glioma cells remains largely unclear. Methods: With the aid of patch-clamp technology, we investigated the effects of TMZ on the ionic currents in U373 glioma cells. The mRNA expression of KCNN4 (KCa3.1 in U373 glioma cells and TMZ's effect on K+ currents in these KCNN4 siRNA-transfected U373 cells were investigated. Results: In whole-cell recordings, TMZ decreased the amplitude of voltage-dependent K+ currents (IK in U373 cells. TMZ-induced IK inhibition was reversed by ionomycin or 1-ethyl-2-benzimidazolinone (1-EBIO. In cell-attached configuration, TMZ concentration-dependently reduced the activity of intermediate-conductance Ca2+-activated K+ (IKCa channels with an IC50 value of 9.2 µM. Chlorzoxazone or 1-EBIO counteracted the TMZ-induced inhibition of IKCa channels. Although TMZ was unable to modify single-channel conductance, its inhibition of IKCa channels was weakly voltage-dependent and accompanied by a significant prolongation in the slow component of mean closed time. However, neitherlarge-conductance Ca2+-activated (BKCa nor inwardly rectifying K+ (Kir channels were affected by TMZ. In current-clamp mode, TMZ depolarized the cell membrane and 1-EBIO reversed TMZ-induced depolarization. TMZ had no effect on IK in KCNN4 siRNA-transfected U373 cells. Conclusion: In addition to the DNA damage it does, its inhibitory effect on IKCa channels accompanied by membrane depolarization could be an important mechanism underlying TMZ-induced antineoplastic actions.

  17. Modeling intermediate product selection under production and storage capacity limitations in food processing

    DEFF Research Database (Denmark)

    Kilic, Onur Alper; Akkerman, Renzo; Grunow, Martin

    2009-01-01

    In the food industry products are usually characterized by their recipes, which are specified by various quality attributes. For end products, this is given by customer requirements, but for intermediate products, the recipes can be chosen in such a way that raw material procurement costs...... with production and inventory planning, thereby considering the production and storage capacity limitations. The resulting model can be used to solve an important practical problem typical for many food processing industries....

  18. Strong nuclear enhancement in intermediate mass Drell-Yan production

    CERN Document Server

    Jian Wei Qiu

    2002-01-01

    We calculate nuclear effect in Drell-Yan massive lepton-pair production in terms of parton multiple scattering in Quantum Chromodynamics (QCD). We present the nuclear modification to inclusive Drell-Yan cross sections d sigma /dQ/sup 2/ in terms of multiparton correlation functions. By extracting the size of the correlation functions from measured Drell-Yan transverse momentum broadening in nuclear media, we determine the nuclear modification at O( alpha /sub s//Q/sup 2/). We find that the nuclear modification strongly enhances the inclusive Drell-Yan cross section in the intermediate mass region (IMR): 1.5

  19. Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Orazov, Marat; Davis, Mark E.

    2015-09-08

    Retro-aldol reactions have been implicated as the limiting steps in catalytic routes to convert biomass-derived hexoses and pentoses into valuable C2, C3, and C4 products such as glycolic acid, lactic acid, 2-hydroxy-3-butenoic acid, 2,4-dihydroxybutanoic acid, and alkyl esters thereof. Due to a lack of efficient retro-aldol catalysts, most previous investigations of catalytic pathways involving these reactions were conducted at high temperatures (≥160 °C). Here, we report moderate-temperature (around 100 °C) retro-aldol reactions of various hexoses in aqueous and alcoholic media with catalysts traditionally known for their capacity to catalyze 1,2-intramolecular carbon shift (1,2-CS) reactions of aldoses, i.e., various molybdenum oxide and molybdate species, nickel(II) diamine complexes, alkali-exchanged stannosilicate molecular sieves, and amorphous TiO2–SiO2 coprecipitates. Solid Lewis acid cocatalysts that are known to catalyze 1,2-intramolecular hydride shift (1,2-HS) reactions that enable the formation of α-hydroxy carboxylic acids from tetroses, trioses, and glycolaldehyde, but cannot readily catalyze retro-aldol reactions of hexoses and pentoses at these moderate temperatures, are shown to be compatible with the aforementioned retro-aldol catalysts. The combination of a distinct retro-aldol catalyst with a 1,2-HS catalyst enables lactic acid and alkyl lactate formation from ketohexoses at moderate temperatures (around 100 °C), with yields comparable to best-reported chemocatalytic examples at high temperature conditions (≥160 °C). The use of moderate temperatures enables numerous desirable features such as lower pressure and significantly less catalyst deactivation.

  20. Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process

    DEFF Research Database (Denmark)

    Lehtinen, Tapio; Efimova, Elena; Tremblay, Pier-Luc

    2017-01-01

    in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral......Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long...... chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi...

  1. Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process.

    Science.gov (United States)

    Lehtinen, Tapio; Efimova, Elena; Tremblay, Pier-Luc; Santala, Suvi; Zhang, Tian; Santala, Ville

    2017-11-01

    Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral chemicals or biofuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Methods of forming single source precursors, methods of forming polymeric single source precursors, and single source precursors and intermediate products formed by such methods

    Science.gov (United States)

    Fox, Robert V.; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin; Margulieux, Kelsey R.; Holland, Andrew W.

    2012-12-04

    Methods of forming single source precursors (SSPs) include forming intermediate products having the empirical formula 1/2{L.sub.2N(.mu.-X).sub.2M'X.sub.2}.sub.2, and reacting MER with the intermediate products to form SSPs of the formula L.sub.2N(.mu.-ER).sub.2M'(ER).sub.2, wherein L is a Lewis base, M is a Group IA atom, N is a Group IB atom, M' is a Group IIIB atom, each E is a Group VIB atom, each X is a Group VIIA atom or a nitrate group, and each R group is an alkyl, aryl, vinyl, (per)fluoro alkyl, (per)fluoro aryl, silane, or carbamato group. Methods of forming polymeric or copolymeric SSPs include reacting at least one of HE.sup.1R.sup.1E.sup.1H and MER with one or more substances having the empirical formula L.sub.2N(.mu.-ER).sub.2M'(ER).sub.2 or L.sub.2N(.mu.-X).sub.2M'(X).sub.2 to form a polymeric or copolymeric SSP. New SSPs and intermediate products are formed by such methods.

  3. Total Syntheses of Polycyclic Polyprenylated Acylphloroglucinol Natural Products and Analogs Utilizing Alkylative Dearomatizations and Cationic Cyclizations

    Science.gov (United States)

    Boyce, Jonathan H.

    Polycyclic polyprenylated acylphloroglucinols (PPAPs) are structurally complex natural products with promising biological activities. These compounds have interesting anticancer and anti-HIV properties as well as other biological activities making them highly attractive synthetic targets. We report a stereodivergent, asymmetric total synthesis of (-)-clusianone in six steps from commercial materials. We have implemented a challenging cationic cyclization forging a bond between two sterically encumbered quaternary carbon atoms. Mechanistic studies point to the unique ability of formic acid to mediate the cyclization forming the clusianone framework. We also present a biosynthesis-inspired, diversity-oriented synthesis approach for rapid construction of PPAP analogs via palladium-catalyzed dearomative conjunctive allylic alkylation (DCAA). These efficient palladium-catalyzed protocols construct the [3.3.1]-bicyclic PPAP core in a single step from their stable aromatic precursors. The first syntheses of 13,14-didehydroxyisogarcinol and garcimultiflorone A stereoisomers are reported in six steps from a commercially available phloroglucinol. Lewis acid-controlled, diastereoselective cationic oxycyclizations enabled asymmetric syntheses of (-)-6-epi-13,14-didehydroxyisogarcinol and (+)-30-epi-13,14-didehydroxyisogarcinol. A similar strategy enabled production of the meso-derived isomers (+/-)-6,30- epi-13,14-didehydroxyisogarcinol and (+/-)-6,30-epi -garcmultiflorone A. A convenient strategy for gram scale synthesis of these stereoisomers was developed utilizing diastereomer separation at a later stage in the synthesis that minimized the number of necessary synthetic operations to access all possible stereoisomers. Finally, we report cationic rearrangements of dearomatized acylphloroglucinols leading to the formation of unprecedented PPAP scaffolds. A novel type A [3.3.1]-bicyclic PPAP was produced as a major product and the structure confirmed by X-ray crystallographic

  4. 75 FR 33824 - Pharmaceutical Products and Chemical Intermediates, Fourth Review: Advice Concerning the Addition...

    Science.gov (United States)

    2010-06-15

    ... Intermediates, Fourth Review: Advice Concerning the Addition of Certain Products to the Pharmaceutical Appendix..., Pharmaceutical Products and Chemical Intermediates, Fourth Review: Advice Concerning the Addition of Certain...-zero initiative are conducting a fourth review to determine if products can be added to the initiative...

  5. Mechanisms of oxidation reactions of alkyl and aryl derivatives of aniline and p-phenylenediamine by cerium (4) in perchloric acid aqueous solutions

    International Nuclear Information System (INIS)

    Ignachak, M.; Dzegets, Yu.

    1989-01-01

    The mechanisms of oxidation reactions of alkyl, N-alkyl and N-aryl derivatives of aniline and p-phenylenediamine by cerium (4) in perchloric acid aqueous solutions are studied. The possible mechanisms of the above reactions are presented; the possibility of preparation of some intermediate products of these reactions using Ce(4) as an oxidant is pointed out

  6. Atmosphere-Controlled Chemoselectivity: Rhodium-Catalyzed Alkylation and Olefination of Alkylnitriles with Alcohols.

    Science.gov (United States)

    Li, Junjun; Liu, Yuxuan; Tang, Weijun; Xue, Dong; Li, Chaoqun; Xiao, Jianliang; Wang, Chao

    2017-10-17

    The chemoselective alkylation and olefination of alkylnitriles with alcohols have been developed by simply controlling the reaction atmosphere. A binuclear rhodium complex catalyzes the alkylation reaction under argon through a hydrogen-borrowing pathway and the olefination reaction under oxygen through aerobic dehydrogenation. Broad substrate scope is demonstrated, permitting the synthesis of some important organic building blocks. Mechanistic studies suggest that the alkylation product may be formed through conjugate reduction of an alkene intermediate by a rhodium hydride, whereas the formation of olefin product may be due to the oxidation of the rhodium hydride complex with molecular oxygen. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Product prioritization in a two-stage food production system with intermediate storage

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van Donk, Dirk Pieter

    2007-01-01

    In the food-processing industry, usually a limited number of storage tanks for intermediate storage is available, which are used for different products. The market sometimes requires extremely short lead times for some products, leading to prioritization of these products, partly through...... the dedication of a storage tank. This type of situation has hardly been investigated, although planners struggle with it in practice. This paper aims at investigating the fundamental effect of prioritization and dedicated storage in a two-stage production system, for various product mixes. We show...... the performance improvements for the prioritized product, as well as the negative effects for the other products. We also show how the effect decreases with more storage tanks, and increases with more products....

  8. Perfluorinated alkylated substances in vegetables collected in four European countries; raw and processed products

    NARCIS (Netherlands)

    Herzke, D.; Huber, S.; Bervoets, L.; D'Hollander, W.; Hajslova, J.; Pulkrabova, J.; Brambilla, G.; De Filippis, S.P.; Klenow, S.; Heinemeyer, G.; de Voogt, P.

    2013-01-01

    The human diet is recognised as one possible major exposure route to the overall perfluorinated alkylated substances (PFAS) burden of the human population, resulting directly from contamination of dietary food items, as well as migration of PFAS from food packaging or cookware. Most European

  9. Enzymatic production of alkyl esters through alcoholysis: A critical evaluation of lipases and alcohols

    DEFF Research Database (Denmark)

    Li, Deng; Xu, Xuebing; Gudmundur G, Haraldsson

    2005-01-01

    yield of FA alkyl esters, with yields well over 90% for methanol, absolute ethanol, and 1-propanol. Overall, 96% ethanol was the preferred alcohol for all lipases except Novozym 435, and ethanolysis reactions reached the maximal conversion efficiency. Increasing the water content in the system resulted...

  10. The effect of alkylation route on ethyltoluene production over different structural types of zeolites

    Czech Academy of Sciences Publication Activity Database

    Ogunbadejo, B.; Aitani, A.; Čejka, Jiří; Kubů, Martin; Al-Khattaf, S.

    2016-01-01

    Roč. 306, DEC 2016 (2016), s. 1071-1080 ISSN 1385-8947 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : ethyltoluenes * alkylation * toluene Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.216, year: 2016

  11. Modeling C1-C4 Alkyl Nitrate Photochemistry and Their Impacts on O3 Production in Urban and Suburban Environments of Hong Kong

    Science.gov (United States)

    Lyu, X. P.; Guo, H.; Wang, N.; Simpson, I. J.; Cheng, H. R.; Zeng, L. W.; Saunders, S. M.; Lam, S. H. M.; Meinardi, S.; Blake, D. R.

    2017-10-01

    As intermediate products of photochemical reactions, alkyl nitrates (RONO2) regulate ozone (O3) formation. In this study, a photochemical box model incorporating master chemical mechanism well reproduced the observed RONO2 at an urban and a mountainous site, with index of agreement in the range of 0.66-0.73. The value 0.0003 was identified to be the most appropriate branching ratio for C1 RONO2, with the error less than 50%. Although levels of the parent hydrocarbons and nitric oxide (NO) were significantly higher at the urban site than the mountainous site, the production of C2-C3 RONO2 was comparable to or even lower than at the mountainous site, due to the lower concentrations of oxidative radicals in the urban environment. Based on the profiles of air pollutants at the mountainous site, the formation of C2-C4 RONO2 was limited by NOx (volatile organic compounds (VOCs)) when total volatile organic compounds (TVOCs)/NOx was higher (lower) than 10.0 ± 0.4 parts per billion by volume (ppbv)/ppbv. This dividing ratio decreased (p controlling O3 formation and the relative abundances of TVOCs and NOx.

  12. Production of intermediate energy beams by high speed rotors

    International Nuclear Information System (INIS)

    Nutt, C.W.; Bale, T.J.; Cosgrove, P.; Kirby, M.J.

    1975-01-01

    A rotor apparatus intended for the study of gas/surface interaction processes is presently nearing completion. The carbon fiber rotors under consideration are constructed with shapes derived from long thin cylindrical rods oriented with the longest axis in a horizontal plane, and spun in a horizontal plane about an axis which is perpendicular to the long axis and passes through the mid-point of the cylinder. The beam formation processes are discussed and rotor diagrams presented. Performance of these types of high speed rotor show them to have a very important future as sources of intermediate energy molecular beams

  13. Structure of a low-population intermediate state in the release of an enzyme product.

    Science.gov (United States)

    De Simone, Alfonso; Aprile, Francesco A; Dhulesia, Anne; Dobson, Christopher M; Vendruscolo, Michele

    2015-01-09

    Enzymes can increase the rate of biomolecular reactions by several orders of magnitude. Although the steps of substrate capture and product release are essential in the enzymatic process, complete atomic-level descriptions of these steps are difficult to obtain because of the transient nature of the intermediate conformations, which makes them largely inaccessible to standard structure determination methods. We describe here the determination of the structure of a low-population intermediate in the product release process by human lysozyme through a combination of NMR spectroscopy and molecular dynamics simulations. We validate this structure by rationally designing two mutations, the first engineered to destabilise the intermediate and the second to stabilise it, thus slowing down or speeding up, respectively, product release. These results illustrate how product release by an enzyme can be facilitated by the presence of a metastable intermediate with transient weak interactions between the enzyme and product.

  14. Ethanol Production from Different Intermediates of Sugar Beet Processing

    OpenAIRE

    Mladen Pavlečić; Ivna Vrana; Kristijan Vibovec; Mirela Ivančić Šantek; Predrag Horvat; Božidar Šantek

    2010-01-01

    In this investigation, the production of ethanol from the raw sugar beet juice and raw sugar beet cossettes has been studied. For ethanol production from the raw sugar beet juice, batch and fed-batch cultivation techniques in the stirred tank bioreactor were used, while batch ethanol production from the raw sugar beet cossettes was carried out in horizontal rotating tubular bioreactor (HRTB). In both cases, Saccharomyces cerevisiae was used as a production microorganism. During batch ethanol ...

  15. Isobutane/olefin-alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Waitkamp, J.; Maixner, S.

    1983-11-01

    Isobutane/olefin-alkylation - technology and reaction mechanism of a refinery process for production of high octane gasoline components: The alkylation of i-butane with olefins, especially with butenes, is a process for the conversion of light byproducts of a catalytic cracker to high quality gasoline components. Alkylate is a complex mixture of i-paraffins containing 5 to ca. 12 carbon atoms. Due to their octane numbers the four trimethylpentane isomers are the most desirable product components. Indeed, under optimum process conditions these isomers are the main products. Presently, alkylation capacity in the western world amounts to more than 40x10/sup 6/ t/a. Most units are located in the USA. Two liquid-phase processes using sulfuric acid and hydrofluoric acid, respectively, are of commercial importance. At present, there is a definite trend towards HF-alkylation. The reaction mechanism which proceeds via carbocations, is extremely complex. It is composed of a great variety of individual steps. Modern mechanistic concepts are discussed.

  16. Alkylation of histidine residues of Bothrops jararacussu venom proteins and isolated phospholipases A2: a biotechnological tool to improve the production of antibodies.

    Science.gov (United States)

    Guimarães, C L S; Andrião-Escarso, S H; Moreira-Dill, L S; Carvalho, B M A; Marchi-Salvador, D P; Santos-Filho, N A; Fernandes, C A H; Fontes, M R M; Giglio, J R; Barraviera, B; Zuliani, J P; Fernandes, C F C; Calderón, L A; Stábeli, R G; Albericio, F; da Silva, S L; Soares, A M

    2014-01-01

    Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) by p-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.

  17. Alkylation of Histidine Residues of Bothrops jararacussu Venom Proteins and Isolated Phospholipases A2: A Biotechnological Tool to Improve the Production of Antibodies

    Directory of Open Access Journals (Sweden)

    C. L. S. Guimarães

    2014-01-01

    Full Text Available Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2 of this toxin (BthTX-I and BthTX-II were chemically modified (alkylation by p-bromophenacyl bromide (BPB in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated. BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2 diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.

  18. Exclusive measurements of neutral pion production at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Turriso, R. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Riggi, F.; Russo, G.; Turriso, R.; Bellia, G.; Migneco, E. [Catania Univ. (Italy). Ist. di Fisica; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; FInocchiaro, P.; Maiolino, C.; Migneco, E.; Piattelli, P.; Sapienza, P. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Peghaire, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)

    1995-12-31

    Neutral pion production has been studied in the {sup 36}Ar + {sup 27}Al reaction at 94 MeV/ nucleon with the aim to get a quantitative estimate of the impact parameter involved in the process. A near 4{pi} multidetector has been used to detect both gamma rays originating from the {pi}deg decay and associated charged particles. The charged particle multiplicity has been used in the present analysis as a global variable to extract the impact parameter scale. A comparison with Boltzmann-Nordheim-Vlasov (BNV) calculations, which take into account the effect of the pion reabsorption in the nuclear matter, has been performed. (author) 23 refs.

  19. Exclusive measurements of neutral pion production at intermediate energies

    International Nuclear Information System (INIS)

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Turriso, R.; Riggi, F.; Russo, G.; Turriso, R.; Bellia, G.; Migneco, E.; Peghaire, A.

    1995-01-01

    Neutral pion production has been studied in the 36 Ar + 27 Al reaction at 94 MeV/ nucleon with the aim to get a quantitative estimate of the impact parameter involved in the process. A near 4π multidetector has been used to detect both gamma rays originating from the πdeg decay and associated charged particles. The charged particle multiplicity has been used in the present analysis as a global variable to extract the impact parameter scale. A comparison with Boltzmann-Nordheim-Vlasov (BNV) calculations, which take into account the effect of the pion reabsorption in the nuclear matter, has been performed. (author)

  20. The production of refined intermediate fuels with high temperature reactors

    International Nuclear Information System (INIS)

    Nowacki, P.J.

    1977-01-01

    Power plants can be divided into conventional steam plants, fueled with hard coal, lignite or liquid fuel, hydroelectric plants and nuclear plants, their chief use was or is the production of electric energy and - in certain cases only - of production of process heat, using steam or hot water for process heat in industry and district heating for residential and commercial purposes. The part played by electricity in the whole energy demand is of the order of 10% to 25% the total demand, the rest is necessary for supplying process heat below 200 0 C or above 200 0 C, up to some 1500 0 C. The present distribution of energy demands is covered chiefly by liquid fuel, coal and lignite, water energy and increasing steps by nuclear fuel. It is well known that the erection of nuclear energy plants is a necessity for today and for the future. There is another necessity, i.e. to utilize the primary energy resources in a complex way i.e. to supply electricity as energy vector and other fuels as process heat as new energy vectors. These manmade fuels - whether in a gaseous or liquid phase - contain hydrogen, and one can believe, the world is entering a new energy civilisation in utilizing hydrogen and its compounds as second energy vector. The author has taken up the task to investigate this new problem of process, heat in the form of hydrogen and its compounds, by evaluating their present and future production, based on the utilization of natural gas, oil coal, water and the nuclear heat of helium, available in a closed circuit as primary coolant in a High - Temeprature Helium cooled reactor, which is symbolized in the paper as HTR. The paper deals in more detail with the following application of Nuclear Heat: hydrogasification, direct reduction of ore, mainly iron ores, ammonia synthesis, methanol synthesis Hydrocracking, long distance transfer of process heat (chemical heat pipe), hydrogenation of coal, Fischer - Tropsch synthesis, oxosynthesis, coal gasification, coal

  1. Make or mix to order: Determining the type of intermediate products in a flour mill

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van der Meer, Dirk; van Donk, Dirk Pieter

    2008-01-01

    In contrast to discrete manufacturers, food-processing companies can sometimes produce the same end products in different ways: either mix early and process or process first and mix later. Moreover, a product can be mixed from different raw materials or intermediates. That implies that choices can...

  2. The production of refined intermediate fuels with high temperature reactors

    International Nuclear Information System (INIS)

    Nowacki, P.J.

    1977-01-01

    The present energy demands are covered chiefly by liquid fuel, coal and lignite, hydro power and increasingly by nuclear fuel. It is accepted that the building of nuclear energy plants is a necessity for today and for the future. A further necessity is to utilize the primary energy resources in a multiple way, i.e. to supply electricity and to produce other fuels for process heat. These man-made fuels all contain hydrogen. The paper investigates process heat in the form of hydrogen and its compounds, by evaluating their present and future production, based on the utilization of natural gas, oil, coal, water and the nuclear heat of helium, available in a closed circuit as primary coolant in a high temperature, helium-cooled reactor. The paper deals in more detail with the following applications of nuclear heat: hydrogasification, direct reduction of ores - mainly iron ore - ammonia synthesis, methanol synthesis, hydrocracking, long-distance transfer of process heat (chemical heat pipe), hydrogenation of coal, Fischer-Tropsch synthesis, oxosynthesis, coal gasification, coal liquefaction, water splitting (thermolysis) and electrolysis. The various chemical reactions are discussed. (author)

  3. Heterofacial alkylation of alkylenediamines by higher alkyl halides

    International Nuclear Information System (INIS)

    Semenov, V.A.; Kryshko, G.M.; Sokal'skaya, L.I.; Zhukova, N.G.

    1985-01-01

    A study of the physiochemical properties of alkylenediamines substituted by lower alkyls, showed that they possess increased complex-forming ability with respect to salts of different metals as titanium, niobium, zirconium, molybdenum, and zinc. To create a simpler method of synthesis of higher tetraaklyalkylalklyenediamines, based on the use of the accessible domestic raw material, the authors investigated the reaction of alkylenediamines with various alkyl halides. It was established that the best reagents can be obtained using alkyl bromides. It is concluded that the procedure of alkylation of alkylenediamines by higher alkyl halides in the presence of water developed permits the production of terraalkylalkylenediamines in one step with good yield and with purity acceptable for use as extraction reagents

  4. Krebs cycle intermediates modulate thiobarbituric acid reactive species (TBARS) production in rat brain in vitro.

    Science.gov (United States)

    Puntel, Robson L; Nogueira, Cristina W; Rocha, João B T

    2005-02-01

    The aim of this study was to investigate the effect of Krebs cycle intermediates on basal and quinolinic acid (QA)- or iron-induced TBARS production in brain membranes. Oxaloacetate, citrate, succinate and malate reduced significantly the basal and QA-induced TBARS production. The potency for basal TBARS inhibition was in the order (IC50 is given in parenthesis as mM) citrate (0.37) > oxaloacetate (1.33) = succinate (1.91) > > malate (12.74). alpha-Ketoglutarate caused an increase in TBARS production without modifying the QA-induced TBARS production. Cyanide (CN-) did not modify the basal or QA-induced TBARS production; however, CN- abolished the antioxidant effects of succinate. QA-induced TBARS production was enhanced by iron ions, and abolished by desferrioxamine (DFO). The intermediates used in this study, except for alpha-ketoglutarate, prevented iron-induced TBARS production. Oxaloacetate, citrate, alpha-ketoglutarate and malate, but no succinate and QA, exhibited significantly iron-chelating properties. Only alpha-ketoglutarate and oxaloacetate protected against hydrogen peroxide-induced deoxyribose degradation, while succinate and malate showed a modest effect against Fe2+/H2O2-induced deoxyribose degradation. Using heat-treated preparations citrate, malate and oxaloacetate protected against basal or QA-induced TBARS production, whereas alpha-ketoglutarate induced TBARS production. Succinate did not offer protection against basal or QA-induced TBARS production. These results suggest that oxaloacetate, malate, succinate, and citrate are effective antioxidants against basal and iron or QA-induced TBARS production, while alpha-ketoglutarate stimulates TBARS production. The mechanism through which Krebs cycle intermediates offer protection against TBARS production is distinct depending on the intermediate used. Thus, under pathological conditions such as ischemia, where citrate concentrations vary it can assume an important role as a modulator of oxidative

  5. Mapping intermediate degradation products of poly(lactic-co-glycolic acid) in vitro.

    Science.gov (United States)

    Li, Jian; Nemes, Peter; Guo, Ji

    2018-04-01

    There is widespread interest in using absorbable polymers, such as poly(lactic-co-glycolic acid) (PLGA), as components in the design and manufacture of new-generation drug eluting stents (DES). PLGA undergoes hydrolysis to progressively degrade through intermediate chemical entities to simple organic acids that are ultimately absorbed by the human body. Understanding the composition and structure of these intermediate degradation products is critical not only to elucidate polymer degradation pathways accurately, but also to assess the safety and performance of absorbable cardiovascular implants. However, analytical approaches to determining the intermediate degradation products have yet to be established and evaluated in a standard or regulatory setting. Hence, we developed a methodology using electrospray ionization mass spectrometry to qualitatively and quantitatively describe intermediate degradation products generated in vitro from two PLGA formulations commonly used in DES. Furthermore, we assessed the temporal evolution of these degradation products using time-lapse experiments. Our data demonstrated that PLGA degradation products via heterogeneous cleavage of ester bonds are modulated by multiple intrinsic and environmental factors, including polymer chemical composition, degradants solubility in water, and polymer synthesis process. We anticipate the methodologies and outcomes presented in this work will elevate the mechanistic understanding of comprehensive degradation profiles of absorbable polymeric devices, and facilitate the design and regulation of cardiovascular implants by supporting the assessments of the associated biological response to degradation products. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1129-1137, 2018. © 2017 Wiley Periodicals, Inc.

  6. Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2003-01-01

    Full Text Available Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCxGC. A GCxGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE, a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere. Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCxGC for the measurement of the parent aromatics generally showed good agreement. Comparison of the concentrations observed by GCxGC to concentration-time profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the

  7. Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

    Science.gov (United States)

    Hamilton, J. F.; Lewis, A. C.; Bloss, C.; Wagner, V.; Henderson, A. P.; Golding, B. T.; Wirtz, K.; Martin-Reviejo, M.; Pilling, M. J.

    2003-11-01

    Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene) with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCxGC). A GCxGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE), a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere). Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCxGC for the measurement of the parent aromatics generally showed good agreement. Comparison of the concentrations observed by GCxGC to concentration-time profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the uncertainties which exist in

  8. IL-1β production by intermediate monocytes is associated with immunopathology in cutaneous leishmaniasis.

    Science.gov (United States)

    Santos, Daniela; Campos, Taís M; Saldanha, Maíra; Oliveira, Sergio C; Nascimento, Mauricio; Zamboni, Dario S; Machado, Paulo R; Arruda, Sérgio; Scott, Phillip; Carvalho, Edgar M; Carvalho, Lucas P

    2017-12-12

    Cutaneous leishmaniasis due to Leishmania braziliensis infection is an inflammatory disease which skin ulcer development is associated with mononuclear cells infiltrate and high levels of inflammatory cytokines production. Recently, NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation and IL-1β production has been associated with increased pathology in murine cutaneous leishmaniasis. We hypothesized that cutaneous leishmaniasis patients have increased expression of NLRP3 leading to high levels of IL-1β production. In this work we show high production of IL-1β in biopsies and Leishmania antigen-stimulated peripheral blood mononuclear cells (PBMC) from patients infected with L. braziliensis, and reduced IL-1β levels after cure. IL-1β production positively correlated with the area of necrosis in lesions and duration of the lesions. The main source of IL-1β was intermediate monocytes (CD14++CD16+). Furthermore, our murine experiments show that IL-1β production in response to L. braziliensis was dependent on NLRP3, Caspase-1 and caspase-recruiting domain (ASC). Additionally, we observed an increased expression of NLRP3 gene in macrophages and NLRP3 protein in intermediate monocytes from cutaneous leishmaniasis patients. These results identify an important role for human intermediate monocytes for the production of IL-1β which contributes to the immunopathology observed in cutaneous leishmanisis patients. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. N- versus O-alkylation: utilizing NMR methods to establish reliable primary structure determinations for drug discovery.

    Science.gov (United States)

    LaPlante, Steven R; Bilodeau, François; Aubry, Norman; Gillard, James R; O'Meara, Jeff; Coulombe, René

    2013-08-15

    A classic synthetic issue that remains unresolved is the reaction that involves the control of N- versus O-alkylation of ambident anions. This common chemical transformation is important for medicinal chemists, who require predictable and reliable protocols for the rapid synthesis of inhibitors. The uncertainty of whether the product(s) are N- and/or O-alkylated is common and can be costly if undetermined. Herein, we report an NMR-based strategy that focuses on distinguishing inhibitors and intermediates that are N- or O-alkylated. The NMR strategy involves three independent and complementary methods. However, any combination of two of the methods can be reliable if the third were compromised due to resonance overlap or other issues. The timely nature of these methods (HSQC/HMQC, HMBC. ROESY, and (13)C shift predictions) allows for contemporaneous determination of regioselective alkylation as needed during the optimization of synthetic routes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Microbial degradation of n-alkyl tetrahydrothiophenes found in petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Fedorak, P.M.; Payzant, J.D.; Montgomery, D.S.; Westlake, D.W.S.

    1988-05-01

    Although n-alkyl-substituted tetrahydrothiophenes are found in nonbiodegraded petroleums, they are not found in petroleums which have undergone biodegradation in their reservoirs. These observations suggested that this group of compounds with alkyl chain lengths from approximately C/sub 10/ to at least C/sub 30/ is biodegradable. Two of these sulfides, 2-n-dodecyltetrahydrothiophene (DTHT) and 2-n-undecyltetrahydrothiophene, were synthesized, and their biodegradabilities were tested by using five gram-positive, n-alkane-degrading bacterial isolates. The alkyl side chains of these compounds were oxidized, and the major intermediates found in 2-n-undecyltetrahydrothiophene- and DTHT-metabolizing cultures were 2-tetrahydrothiophenecarboxylic acid (THTC) and 2-tetrahydrothiopheneacetic acid (THTA), respectively. Four n-alkane-degrading fungi were also shown to degrade DTHT, yielding both THTA and THTC. Quantitation of tetrahydrothiophene ring-containing products in 28-day-old bacterial and fungal cultures suggested that THTC and THTA were metabolized further to unidentified products. In addition, two of the bacterial isolates were shown to degrade a mixture of n-alkyl tetrahydrothiophenes isolated from Bellshill Lake crude oil.

  11. Side chain alkylation of toluene with methanol over basic zeolites - novel production route towards styrene?

    NARCIS (Netherlands)

    Rep, M.; Rep, M.

    2002-01-01

    Styrene is an important monomer for the production of different types of (co-) polymers that are used in, e.g., toys, medical devices, food packaging, paper coatings etc. Styrene is produced with several different industrial processes. In 1998, the production of styrene monomer was approximately 21

  12. Enhancement of alkylation catalysts for improved supercritical fluid regeneration

    Science.gov (United States)

    Ginosar, Daniel M.; Petkovic, Lucia M.

    2010-12-28

    A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

  13. Alkylation of isobutane with butenes in the presence of HNaY zeolite modified by cations of nickel, calcium and rare-earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, O.I.; Panchenkov, G.M.; Plakhotnik, V.A.; Razali, B.; Tolkacheva, Y.I.

    1981-01-01

    A study was made of alkylation of isobutane with n-butenes in the presence of ion-exchange forms of zeolites, containing ions of Ni/sup 2 +/ and rare-earth elements. It was established that the addition to HCaY zeolite of Ni/sup 2 +/ ions reduces alkylate yield and increases the content of intermediate products. The use in the reaction studied of HCaY zeolite containing La/sup 3 +/ or Gd/sup 3 +/ ions increases the content of iso-octane hydrocarbons in the alkylate and reduces the content of fractions C/sub 9/ and higher.

  14. Pair production by photons. Screening corrections for intermediate and high energies

    International Nuclear Information System (INIS)

    Oeverboe, I.

    1978-01-01

    The screening correction to the total cross-section for coherent electron pair production by photons is evaluated for intermediate and high energies, by employing the Born-approximation recoil momentum distribution and accurate relativistic form factors. Results are given for all 3<=Z<=92. For each element the results are presented in terms of a seven-parameter formula which is based on a high-energy expansion of the screened cross-section. (author)

  15. Asymmetry ratio in pair production and the degree of linearly polarized photons at intermediate energies

    CERN Document Server

    Asai, J

    1999-01-01

    In order to initiate the experiments using linearly polarized tagged photons at intermediate energies, it is imperative to know and to monitor the degree of polarization. The relationship is re-examined between the linear polarization of photons and the asymmetry ratio in pair production by such photons. An improved method is proposed in which pairs are prohibited from entering the cone region around the incident photon beam. By restricting the directions of pairs, the asymmetry ratio is much improved. (author)

  16. Diffusion of a new intermediate product in a simple ‘classical‐Schumpeterian’ model

    Science.gov (United States)

    2017-01-01

    Abstract This paper deals with the problem of new intermediate products within a simple model, where production is circular and goods enter into the production of other goods. It studies the process by which the new good is absorbed into the economy and the structural transformation that goes with it. By means of a long‐period method the forces of structural transformation are examined, in particular the shift of existing means of production towards the innovation and the mechanism of differential growth in terms of alternative techniques and their associated systems of production. We treat two important Schumpeterian topics: the question of technological unemployment and the problem of ‘forced saving’ and the related problem of an involuntary reduction of real consumption per capita. It is shown that both phenomena are potential by‐products of the transformation process. PMID:29695874

  17. O-Alkyl Hydroxamates as Metaphors of Enzyme-Bound Enolate Intermediates in Hydroxy Acid Dehydrogenases. Inhibitors of Isopropylmalate Dehydrogenase, Isocitrate Dehydrogenase, and Tartrate Dehydrogenase(1).

    Science.gov (United States)

    Pirrung, Michael C.; Han, Hyunsoo; Chen, Jrlung

    1996-07-12

    The inhibition of Thermus thermophilus isopropylmalate dehydrogenase by O-methyl oxalohydroxamate was studied for comparison to earlier results of Schloss with the Salmonella enzyme. It is a fairly potent (1.2 &mgr;M), slow-binding, uncompetitive inhibitor against isopropylmalate and is far superior to an oxamide (25 mM K(i) competitive) that is isosteric with the ketoisocaproate product of the enzyme. This improvement in inhibition was attributed to its increased NH acidity, which presumably is due to the inductive effect of the hydroxylamine oxygen. This principle was extended to the structurally homologous enzyme isocitrate dehydrogenase from E. coli, for which the compound O-(carboxymethyl) oxalohydroxamate is a 30 nM inhibitor, uncompetitive against isocitrate. The pH dependence of its inhibition supports the idea that it is bound to the enzyme in the anionic form. Another recently discovered homologous enzyme, tartrate dehydrogenase from Pseudomonas putida, was studied with oxalylhydroxamate. It has a relatively low affinity for the enzyme, though it is superior to tartrate. On the basis of these leads, squaric hydroxamates with increased acidity compared to squaric amides directed toward two of these enzymes were prepared, and they also show increased inhibitory potency, though not approaching the nanomolar levels of the oxalylhydroxamates.

  18. In situ sulfonation of alkyl benzene self-assembled monolayers: product distribution and kinetic analysis.

    Science.gov (United States)

    Katash, Irit; Luo, Xianglin; Sukenik, Chaim N

    2008-10-07

    The sulfonation of aromatic rings held at the surface of a covalently anchored self-assembled monolayer has been analyzed in terms of the rates and isomer distribution of the sulfonation process. The observed product distributions are similar to those observed in solution, though the data obtained suggest that the reaction rate and the ortho/para product ratio depend on the length of the tether anchoring the aryl ring to the monolayer interface. It was also found that the interface becomes progressively more disordered and the observed reaction rates decrease as the reaction progresses. There is no evidence for a bias in favor of reaction at the more exposed para-position nor is there evidence for an enhanced reaction rate due to the increased disorder and/or improved wetting as the reaction proceeds. This is the first detailed study of electrophilic aromatic substitution at a monolayer interface. It introduces new approaches to the spectroscopic analysis of reactions on self-assembled monolayers and provides a new general approach to the analysis of isomeric product distribution in such a setting.

  19. Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

    2007-01-01

    In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hardly...... of systems like this. Contrary to the common sense in operations management, the LPT rule is able to maximize the total production volume per day. Furthermore, we show that adding one tank has considerable effects. Finally, we conclude that the optimal setup frequency for batches in the first stage...

  20. Production of nuclei far from the beta stability line using intermediate-energy heavy ions

    International Nuclear Information System (INIS)

    Guerreau, D.

    1986-05-01

    The production of far unstable nuclei using heavy ion accelerators in the intermediate energy domain is reviewed. The various mechanisms responsible for the production of exotic species, mainly the projectile fragmentation and transfer reactions, are discussed, and the first experimental results presented. Results can be summarized as follows: existence of 4 new isotopes 22 C, 23 N, 29 Ne, 30 Ne; indication of bound character of 71 Ni, 72 Ni; clear evidence for bound character of 23 Si, 27 S, 31 Ar, 35 Ca; indications of bound character of 43 V, 46 Mn, 47 Mn, 48 Fe, 50 Co, 52 Co, 52 Ni, 55 Cu, 56 Cu

  1. Alkyl halide-free heteroatom alkylation and epoxidation facilitated by a recyclable polymer-supported oxidant for the in-flow preparation of diazo compounds.

    Science.gov (United States)

    Nicolle, Simon M; Hayes, Christopher J; Moody, Christopher J

    2015-03-16

    Highly reactive metal carbenes, generated from simple ketones via diazo compounds, including diazo-amides and -phosphonates, using a recyclable reagent in-flow, are transient but versatile electrophiles for heteroatom alkylation reactions and for epoxide formation. The method produces no organic waste, with the only by-products being water, KI and nitrogen, without the attendant hazards of isolation of intermediate diazo compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Broadband Microwave Study of Reaction Intermediates and Products Through the Pyrolysis of Oxygenated Biofuels

    Science.gov (United States)

    Abeysekera, Chamara; Hernandez-Castillo, Alicia O.; Fritz, Sean; Zwier, Timothy S.

    2017-06-01

    The rapidly growing list of potential plant-derived biofuels creates a challenge for the scientific community to provide a molecular-scale understanding of their combustion. Development of accurate combustion models rests on a foundation of experimental data on the kinetics and product branching ratios of their individual reaction steps. Therefore, new spectroscopic tools are necessary to selectively detect and characterize fuel components and reactive intermediates generated by pyrolysis and combustion. Substituted furans, including furanic ethers, are considered second-generation biofuel candidates. Following the work of the Ellison group, an 8-18 GHz microwave study was carried out on the unimolecular and bimolecular decomposition of the smallest furanic ether, 2-methoxy furan, and it`s pyrolysis intermediate, the 2-furanyloxy radical, formed in a high-temperature pyrolysis source coupled to a supersonic expansion. Details of the experimental setup and analysis of the spectrum of the radical will be discussed.

  3. Mechanistic Insights into Solvent and Ligand Dependency in Cu(I)-Catalyzed Allylic Alkylation with gem-Diborylalkanes.

    Science.gov (United States)

    Zhang, Qi; Wang, Bing; Liu, Jia-Qin; Fu, Yao; Wu, Yu-Cheng

    2018-01-19

    The recent Cu-catalyzed allylic substitution reaction between gem-diboryalkane and allyl electrophiles shows intriguing solvent and ligand-controlled regioselectivity. The α-alkylation product was obtained in DMF solvent, while γ-alkylation product was obtained in dioxane solvent and the dioxane and NHC ligand situation. In the present study, density functional theory calculations have been used to investigate the reaction mechanism and origin of the regioselectivity. For both dioxane and DMF, γ-alkylation undergoes successive oxidative addition (CH 2 Bpin trans to leaving group) and direct Cγ-C reductive elimination. The α-alkylation is found to undergo oxidative addition (CH 2 Bpin trans to leaving group), isomerization, and Cα-C reductive elimination rather than the previously proposed oxidative addition (-CH 2 Bpin cis to the leaving group) and Cα-C reductive elimination. The γ-alkylation and α-alkylation is, respectively, favorable for dioxane and DMF solvent, which is consistent with the γ- and α-selectivity in experiment. The solvent interferes the isomerization step, thereby affects the relative facility of the α- and γ-alkylation. Further investigation shows that η 1 -intermediate formation promoted by solvent is the rate-determining step of the isomerization. The stronger electron-donating ability of DMF than dioxane facilitates the η 1 -intermediate formation and finally results in the easier isomerization in DMF. For dioxane and NHC situation, in the presence of neutral NHC ligand, the -PO 4 Et 2 group tightly coordinates with the Cu center after the oxidative addition, preventing the isomerization process. The regioselectivity is determined by the relative facility of the oxidative addition step. Therefore, the favorable oxidative addition (in which -CH 2 Bpin trans to the leaving group) results in the facility of γ-alkylation.

  4. Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors

    International Nuclear Information System (INIS)

    Chang Oh; Cliff Davis; Rober Barner; Paul Pickard

    2005-01-01

    The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed to perform thermal-hydraulic evaluations and cycle-efficiency evaluations of the different configurations and coolants. The thermal-hydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. The relative sizes of components provide a relative indication of the capital cost associated with the various configurations. Estimates of the overall cycle efficiency of the various

  5. Liquid microchromatographic analysis of intermediate and final products during the production process of highly molecular Mannich base additives

    Energy Technology Data Exchange (ETDEWEB)

    Zakupra, V.A.; Petrenko, L.M.; Popovich, T.D.

    1982-01-01

    It was shown that a single separation provides data on the content: highly molecular Mannich base parts (for one of the intermediate products and the resultant additive -- with added boric acid), polyisobutylene in a mix with diluting oil and polyisobutylphenol (separately or together) low molecular Mannich base parts (in the latter also concentrated are traces of fatty acids, boric acid and polyethylenepolyamins that did not enter the reaction). To identify structures of extracted Mannich bases and other substances infra-red spectroscopy and ebullioscopy, microanalytic determination of boron and nitrogen were utilized. A more rapid technique of liquid microchromatorgraphy is offered, to be used to monitor additive production.

  6. Nitrous oxide production from reactive nitrification intermediates: a concerted action of biological and chemical processes

    Science.gov (United States)

    Brüggemann, Nicolas; Heil, Jannis; Liu, Shurong; Wei, Jing; Vereecken, Harry

    2017-04-01

    This contribution tries to open up a new perspective on biogeochemical N2O production processes, taking the term bio-geo-chemistry literally. What if a major part of N2O is produced from reactive intermediates of microbiological N turnover processes ("bio…") leaking out of the involved microorganisms into the soil ("…geo…") and then reacting chemically ("…chemistry") with the surrounding matrix? There are at least two major reactive N intermediates that might play a significant role in these coupled biological-chemical reactions, i.e. hydroxylamine (NH2OH) and nitrite (NO2-), both of which are produced during nitrification under oxic conditions, while NO2- is also produced during denitrification under anoxic conditions. Furthermore, NH2OH is assumed to be also a potential intermediate of DNRA and/or anammox. First, this contribution will summarize information about several chemical reactions involving NH2OH and NO2- leading to the formation of N2O. These abiotic reactions are: reactions of NO2- with reduced metal cations, nitrosation reactions of NO2- and soil organic matter (SOM), the reaction between NO2- and NH2OH, and the oxidation of NH2OH by oxidized metal ions. While these reactions can occur over a broad range of soil characteristics, they are ignored in most current N trace gas studies in favor of biological processes only. Disentangling microbiological from purely chemical N2O production is further complicated by the fact that the chemically formed N2O is either undiscernible from N2O produced during nitrification, or shows an intermediate 15N site preference between that of N2O from nitrification and denitrification, respectively. Results from experiments with live and sterilized soil samples, with artificial soil mixtures and with phenolic lignin decomposition model compounds will be presented that demonstrate the potential contribution of these abiotic processes to soil N trace gas emissions, given a substantial leakage rate of these reactive

  7. Growth/no growth models for Zygosaccharomyces rouxii associated with acidic, sweet intermediate moisture food products

    DEFF Research Database (Denmark)

    Nielsen, Cecilie Lykke Marvig; Kristiansen, Rikke M.; Nielsen, Dennis Sandris

    2015-01-01

    The most notorious spoilage organism of sweet intermediate moisture foods (IMFs) is Zygosaccharomyces rouxii, which can grow at low water activity, low pH and in the presence of organic acids. Together with an increased consumer demand for preservative free and healthier food products with less...... sugar and fat and a traditionally long self-life of sweet IMFs, the presence of Z. rouxii in the raw materials for IMFs has made assessment of the microbiological stability a significant hurdle in product development. Therefore, knowledge on growth/no growth boundaries of Z. rouxii in sweet IMFs...... is important to ensure microbiological stability and aid product development. Several models have been developed for fat based, sweet IMFs. However, fruit/sugar based IMFs, such as fruit based chocolate fillings and jams, have lower pH and aw than what is accounted for in previously developed models...

  8. The reaction of Criegee intermediate CH2OO with water dimer: primary products and atmospheric impact.

    Science.gov (United States)

    Sheps, Leonid; Rotavera, Brandon; Eskola, Arkke J; Osborn, David L; Taatjes, Craig A; Au, Kendrew; Shallcross, Dudley E; Khan, M Anwar H; Percival, Carl J

    2017-08-23

    The rapid reaction of the smallest Criegee intermediate, CH 2 OO, with water dimers is the dominant removal mechanism for CH 2 OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%. Incorporating our results into a global chemistry-transport model further reduces HCOOH levels by 10-90%, relative to previous modeling assumptions, which indicates that the reaction CH 2 OO + water dimer by itself cannot resolve the discrepancy between the measured and predicted HCOOH levels.

  9. Alkyl-benzene-sulfonates; Alkylbenzenesulfonates

    Energy Technology Data Exchange (ETDEWEB)

    Marcou, L. [Ecole Superieure de Physique et Chimie Industrielles, 75 - Paris (France)]|[CEN, Comite europeen de normalisation (France)]|[Syndicat francais des producteurs d`agents de surface et produits auxiliaires industriels (ASPA) (France)

    1998-03-01

    The alkyl-benzene-sulfonates, or sulfophenyl-4-alkanes salts, (ABS) are anionic surface agents whose chemical formula is R-C{sub 6} H{sub 4}-SO{sub 3} M (where R is an aliphatic hydro-carbonated radical and M a metal). Like most of the surface agents, the ABS are complicated mixtures of isomers and homologues, the most usual products having 10 or 13 atoms of carbons. Their chemical preparation is carried out in two steps: 1)the alkyl-benzenes production by the alkanes or alkenes condensation on benzene 2)the alkyl-benzenes sulfonation and the neutralization of the sulfonic acids. The environmental impacts of these compounds are also given. (O.M.) 11 refs.

  10. Results of fission product release from intermediate-scale MCCI [molten core-concrete interaction] tests

    International Nuclear Information System (INIS)

    Spencer, B.W.; Thompson, D.H.; Fink, J.K.; Gunther, W.H.; Sehgal, B.R.

    1988-01-01

    A program of reactor-material molten core-concrete interaction (MCCI) tests and related analyses are under way at Argonne National Laboratory under sponsorship of the Electric Power Research Institute (EPRI). The particular objective of these tests is to provide data pertaining to the release of nonvolatile fission products such as La, Ba, and Sr, plus other aerosol materials, from the coupled thermal-hydraulic and chemical processes of the MCCI. The first stages of the program involving small and intermediate-scale tests have been completed. Three small-scale tests (/approximately/5 kg corium) and nine intermediate-scale tests (/approximately/30 kg corium) were performed between September 1985 and September 1987. Real reactor materials were used in these tests. Sustained internal heat generation at nominally 1 kW per kg of melt was provided by direct electrical heating of the corium mixture. MCCI tests were performed with both fully and partially oxidized corium mixtures that contained a variety of nonradioactive materials such as La 2 O 3 , BaO, and SrO to represent fission products. Both limestone/common sand and basaltic concrete basemats were used. The system was instrumented for characterization of the thermal hydraulic, chemical, gas release, and aerosol release processes

  11. Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

    Science.gov (United States)

    Wikandari, Rachma; Sari, Noor Kartika; A'yun, Qurrotul; Millati, Ria; Cahyanto, Muhammad Nur; Niklasson, Claes; Taherzadeh, Mohammad J

    2015-02-01

    Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., γ-hexalactone and γ-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of γ-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of γ-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, γ-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L.

  12. Biological Production of a Hydrocarbon Fuel Intermediate Polyhydroxybutyrate (Phb) from a Process Relevant Lignocellulosic Derived Sugar

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Mohagheghi, Ali; Mittal, Ashutosh; Pilath, Heidi; Johnson, David K.

    2015-03-22

    PHAs are synthesized by many microorganisms to serve as intracellular carbon storage molecules. In some bacterial strains, PHB can account for up to 80% of cell mass. In addition to its application in the packaging sector, PHB also has great potential as an intermediate in the production of hydrocarbon fuels. PHB can be thermally depolymerized and decarboxylated to propene which can be upgraded to hydrocarbon fuels via commercial oligomerization technologies. In recent years a great effort has been made in bacterial production of PHB, yet the production cost of the polymer is still much higher than conventional petrochemical plastics. The high cost of PHB is because the cost of the substrates can account for as much as half of the total product cost in large scale fermentation. Thus searching for cheaper and better substrates is very necessary for PHB production. In this study, we demonstrate production of PHB by Cupriavidus necator from a process relevant lignocellulosic derived sugar stream, i.e., saccharified hydrolysate slurry from pretreated corn stover. Good cell growth was observed on slurry saccharified with advanced enzymes and 40~60% of PHB was accumulated in the cells. The mechanism of inhibition in the toxic hydrolysate generated by pretreatment and saccharification of biomass, will be discussed.

  13. Design and operation of a filter reactor for continuous production of a selected pharmaceutical intermediate

    DEFF Research Database (Denmark)

    Christensen, Kim Müller; Pedersen, Michael Jønch; Dam-Johansen, Kim

    2012-01-01

    -batch operation, are reduced impurity formation and the use of much lower reactor volumes (factor of 1000 based on the laboratory reactor) and less solvent consumption (from 5.8 to 2.3L/kg reactant). Added challenges include handling of continuous solid powder feeding, stable pumping of reactive slurries......A novel filter reactor system for continuous production of selected pharmaceutical intermediates is presented and experimentally verified. The filter reactor system consists of a mixed flow reactor equipped with a bottom filter, to retain solid reactant particles, followed by a conventional plug...... in tetrahydrofuran solvent. The use of the filter reactor design was explored by examining the transferability of a synthesis step in a present full-scale semi-batch pharmaceutical production into continuous processing. The main advantages of the new continuous minireactor system, compared to the conventional semi...

  14. TECHNICAL MEANS FOR OBTAINING INTERMEDIATE PRODUCTS OF THE CASING AND TOPPINGS FOR EXTRUDED FOOD PRODUCTS

    Directory of Open Access Journals (Sweden)

    A. N. Pal’chikov

    2015-01-01

    Full Text Available The following article is devoted to the new technical facilities for food production, which technological chain of production process includes computer hardware as a part of the equipment used for body of semi-processed food preparation, blancher for hydrobionts and abrasive blender. For the whole group of the necessary equipment the principal schemes are designed, and the abrasive blender was tested during the experimental approbation to reveal the optimal design. The culinary fish pastes have already been produced in the enterprises in many countries for many years and they are particularly popular in Japan, Germany, Scandinavian and other country. In Poland the mixtures of fish pasted have become widely spread, and are used for production of portioned meals. These pastes may be blended into larger or smaller pieces. The aromatization process of such pastes is conducted with adding the liquid smoke, natural or synthetic fragrances. There is an increasing popularization of the use of flaxseed as a source of alpha-linoleic acid, high-quality protein, phenolics, fiber and minerals. Products with flax meal can be recommended for inclusion in the diet to make up for the deficit of polyunsaturated fatty acids, dietary fiber. In this regard, it is appropriate to use the semi-finished product formulations for the respective housings extruded snack food. The results of the conducted research could be used in the production of domestic extruded snacks, which have the form of the cushions with vitaminized dough body and hydrobionts stuffing if setting the special extrusion modes.

  15. Parameters determining the quality of charqui, an intermediate moisture meat product.

    Science.gov (United States)

    Torres, E A; Shimokomaki, M; Franco, B D; Landgraf, M; Carvalho, B C; Santos, J C

    1994-01-01

    Charqui is a typical Brazilian meat product obtained by salting and sun-drying beef samples. The chemical, physical and microbiological characteristics of the charqui were evaluated throughout processing and storage. The results confirm charqui is an intermediate moisture meat product (A(w) = 0·70-0·75). A close relationship between moisture, pretein and ash vaiues was found, suggesting the possibility of using the resulting charqui A(w) value as a parameter to define the product instead of the official moisture and mineral residue contents. The TBA determination, which expresses the state of lipid oxidation, rapidly reached the maximum value, corroborating the previous observations on the salt pro-oxidant role, and then decreased gradually. A gradual decrease in microorganism count during processing and storage of charqui was also observed. These results indicate the feasibility of obtaining a final product with a low level of microbial count when raw materials of good quality, and adequate handling conditions, are used for charqui production. Copyright © 1994. Published by Elsevier Ltd.

  16. N-Alkylation Using Sodium Triacetoxyborohydride with Carboxylic Acids as Alkyl Sources.

    Science.gov (United States)

    Tamura, Satoru; Sato, Keigo; Kawano, Tomikazu

    2018-01-01

    A versatile N-alkylation was performed using sodium triacetoxyborohydride and carboxylic acid as an alkyl source. The combination of these reagents furnished products different from those given previously by a similar reaction. Moreover, the mild conditions of our method allowed some functional groups to remain through the reaction, whereas they would react and be converted into other moieties in the similar reductive N-alkylation reported previously. Herein, we provide a new procedure for the preparation of various compounds containing nitrogen atoms.

  17. Structural Analysis of Substrate, Reaction Intermediate, and Product Binding in Haemophilus influenzae Biotin Carboxylase

    Science.gov (United States)

    Broussard, Tyler C.; Pakhomova, Svetlana; Neau, David B.; Bonnot, Ross; Waldrop, Grover L.

    2015-01-01

    Acetyl-CoA carboxylase catalyzes the first and regulated step in fatty acid synthesis. In most Gram-negative and Gram-positive bacteria, the enzyme is composed of three proteins: biotin carboxylase, a biotin carboxyl carrier protein (BCCP), and carboxyltransferase. The reaction mechanism involves two half-reactions with biotin carboxylase catalyzing the ATP-dependent carboxylation of biotin-BCCP in the first reaction. In the second reaction, carboxyltransferase catalyzes the transfer of the carboxyl group from biotin-BCCP to acetyl-CoA to form malonyl-CoA. In this report, high-resolution crystal structures of biotin carboxylase from Haemophilus influenzae were determined with bicarbonate, the ATP analogue AMPPCP; the carboxyphosphate intermediate analogues, phosphonoacetamide and phosphonoformate; the products ADP and phosphate; and the carboxybiotin analogue N1′-methoxycarbonyl biotin methyl ester. The structures have a common theme in that bicarbonate, phosphate, and the methyl ester of the carboxyl group of N1′-methoxycarbonyl biotin methyl ester all bound in the same pocket in the active site of biotin carboxylase and as such utilize the same set of amino acids for binding. This finding suggests a catalytic mechanism for biotin carboxylase in which the binding pocket that binds tetrahedral phosphate also accommodates and stabilizes a tetrahedral dianionic transition state resulting from direct transfer of CO2 from the carboxyphosphate intermediate to biotin. PMID:26020841

  18. Photodegradation of 2-chloropyridine in aqueous solution: Reaction pathways and genotoxicity of intermediate products.

    Science.gov (United States)

    Skoutelis, Charalambos; Antonopoulou, Maria; Konstantinou, Ioannis; Vlastos, Dimitris; Papadaki, Maria

    2017-01-05

    2-Chloropyridine, an important precursor of the chemical industry is also a persistent water pollutant. The genotoxicity of photolytically treated 2-chloropyridine aqueous solution to human lymphocytes initially increases and fluctuates during treatment finally reaching the control values after prolonged treatment. Intermediate products formed were identified; a kinetic scheme for their formation is presented. To identify the source of genotoxicity variations and the potential in vitro effects on human lymphocytes of the partially photo-treated aqueous solution, the genotoxicity of four (the only) commercially available intermediates, i.e., 1H-pyrrole-2-carboxaldehyde, 6-chloro-2-pyridinecarboxylic acid, 2,3-dichloropyridine and 2-pyridinecarbonitrile was measured; the obtained results were used for the reasoning on the variation of the solution genotoxic (including clastogenic as well as aneugenic) events and cytotoxic activity. It was found that 1H-pyrrole-2-carboxaldehyde and 6-chloro-2-pyridinecarboxylic acid were highly genotoxic even at the very low concentration measured here. Thus, they likely had a significant contribution to the photolytically treated solution genotoxicity. 2,3-Dichloropyridine was found to be genotoxic but only at concentrations higher than the ones measured in this work. Thus, it was not likely to have contributed to the solution genotoxicity. Finally, at the concentrations measured in this work 2-pyridinecarbonitrile was found to be only cytotoxic. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Alkylation of N-substituted 2-phenylacetamides

    Directory of Open Access Journals (Sweden)

    SLOBODAN D. PETROVIC

    2004-10-01

    Full Text Available Various N-substituted phenylacetamides were alkylated using different alkylating agents under neutral and basic conditions. Reactions were performed at different reaction temperatures and in various solvents. Also, a number of various catalysts were used including phase-transfer catalysts. Reactions were followed using GC or GC-MS technique and the presence as well as the yields of the alkylation products were established. Generally, the best yield and high selectivity in the studied reactions were achieved under basic conditions where in the certain cases some products, mostly N-product, were obtained solely in quantitative yields.

  20. DNA minor groove alkylating agents.

    Science.gov (United States)

    Denny, W A

    2001-04-01

    Recent work on a number of different classes of anticancer agents that alkylate DNA in the minor groove is reviewed. There has been much work with nitrogen mustards, where attachment of the mustard unit to carrier molecules can change the normal patterns of both regio- and sequence-selectivity, from reaction primarily at most guanine N7 sites in the major groove to a few adenine N3 sites at the 3'-end of poly(A/T) sequences in the minor groove. Carrier molecules discussed for mustards are intercalators, polypyrroles, polyimidazoles, bis(benzimidazoles), polybenzamides and anilinoquinolinium salts. In contrast, similar targeting of pyrrolizidine alkylators by a variety of carriers has little effect of their patterns of alkylation (at the 2-amino group of guanine). Recent work on the pyrrolobenzodiazepine and cyclopropaindolone classes of natural product minor groove binders is also reviewed.

  1. Trichloroacetimidates as Alkylating Reagents and Their Application in the Synthesis of Pyrroloindoline Natural Products and Synthesis of Small Molecule Inhibitors of Src Homology 2 Domain-Containing Inositol Phosphatase (SHIP)

    Science.gov (United States)

    Adhikari, Arijit A.

    was applied towards the synthesis of natural products and their analogs. The pyrroloindoline ring system is found in many alkaloids and cyclic peptides which mainly differ in the substitution at the C3a position. To provide rapid access to these natural products a diversity-oriented strategy was established via displacement of C3a-trichloroacetimidate pyrroloindoline. Carbon, oxygen, sulfur and nitrogen nucleophiles were all shown to undergo substitution reactions with these trichloroacetimidates in the presence of a Lewis acid catalyst. In order to demonstrate the utility of this new method it was applied towards the synthesis of arundinine and a formal synthesis of psychotriasine. Current investigations involve the application of this method towards the synthesis of a complex pyrroloindoline natural product kapakahine C and the progress made therein has been discussed. The reactivity of trichloroacetimidates was also investigated for the selective C3-alkylation of 2,3-disubstituted indoles to provide indolenines. Indolenines serve as useful intermediates in the synthesis of many complex alkaloids. Different benzylic and allylic trichloroacetimidates were shown to provide 3,3'-disubstituted indolenines with high yields in the presence of catalytic amounts of Lewis acids. Various substituted indoles were evaluated under these reaction conditions. This methodology was also applied towards the synthesis of the core tetracyclic ring system found in communesin natural products. In addition to the above work, synthesis of small molecule inhibitors of Src Homology 2 Domain-Containing Inositol Phosphatase (SHIP) has also been described. Aberrations in the phosphoinositide 3-kinase (PI3K) cellular signaling pathway can lead to diseased cellular states like cancer. Herein we have reported stereoselective synthesis of two quinoline based small molecule SHIP inhibitors. The lead compounds and their analogs were tested for their activities against SHIP by Malachite green assay

  2. Characterization of surface dielectric barrier discharge influenced by intermediate frequency for ozone production

    International Nuclear Information System (INIS)

    Abdelaziz, Ayman A; Ishijima, Tatsuo; Seto, Takafumi; Otani, Yoshio; Osawa, Naoki; Wedaa, Hassan

    2016-01-01

    The aim of this study is to investigate the effect of the intermediate frequency (1–10 kHz) of the sinusoidal driving voltage on the characteristics of a developed surface dielectric barrier discharge (SDBD)-based reactor having spikes on its discharge electrode. Moreover, its influence on the production of ozone and nitrogen oxide byproducts is evaluated. The results show that SDBD is operated in the filamentary mode at all the frequencies. Nevertheless, the pulses of the discharge current at high frequencies are much denser and have higher amplitudes than those at low frequencies. The analysis of the power consumed in the reactor shows that a small portion of the input power is dissipated in the dielectric material of SDBD source, whereas the major part of the power is consumed in the plasma discharge. The results of the ozone production show that higher frequencies have a slightly adverse effect on the ozone production at relatively high energy density values, where the ozone concentration is slightly decreased when the frequency is increased at the same energy density. The temperature of the discharge channels and gas is not a crucial factor for the decomposition of ozone in this reactor, while the results of the measurements of nitrogen oxides characteristics indicate that the formation of NO and NO 2 has a significant adverse effect on the production efficiency of ozone due to their oxidation to another nitrogen oxides and their catalytic effect. (paper)

  3. Analytical method used for intermediate products in continuous distillation of furfural

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.L.; Jia, M.; Wang, L.J.; Deng, Y.X.

    1981-01-01

    During distillation of furfural, analysis of main components in the crude furfural condensate and intermediate products is very important. Since furfural and methylfurfural are homologous and both furfural and acetone contain a carbonyl group, components in the sample must be separated before analysis. An improved analytical method has been studied, the accuracy and precision of which would meet the requirement of industrial standards. The analytical procedure was provided as follows: to determine the furfural content with gravimetric method of barbituric acid; to determine the methanol content with dichromate method after precipitating furfural and acetone, and distilling the liquid for analysis; and to determine the methylfurfural content with bromide-bromate method, which can be used only in the sample containing higher content of methylfurfural. For the sample in low content, the gas-liquid chromatographic method can be used. 7 references.

  4. Production and Characterization of Polymeric Lignin Degradation Intermediates from Two Different Streptomyces spp.

    Science.gov (United States)

    Borgmeyer, J R; Crawford, D L

    1985-02-01

    Previous investigations have identified a quantitatively major intermediate of lignin degradation by Streptomyces viridosporus. The intermediate, a modified lignin polymer, acid-precipitable polymeric lignin (APPL), is released as a water-soluble catabolite and has been recovered in amounts equivalent to 30% of the lignin originally present in a corn stover lignocellulose substrate after degradation by this actinomycete. In the present work, APPLs were collected at various time intervals from cultures of two highly ligninolytic Streptomyces sp. strains, S. viridosporus T7A and S. badius 252, growing on corn stover lignocellulose. APPL production was measured over time, and the chemistry of APPLs produced by each organism after different time intervals was compared. Chemical characterizations included assays for lignin, carbohydrate, and ash contents, molecular weight distributions by gel permeation chromatography, and chemical degradation analyses by permanganate oxidation, acidolysis, and alkaline ester hydrolysis. Differences between the organisms were observed in the cultural conditions required for APPL production and in the time courses of APPL accumulation. S. viridosporus produced APPL in solid-state fermentation over a 6- to 8-week incubation period, whereas S. badius produced as much or more APPL, but only in liquid culture and over a 7- to 8-day incubation period. The chemistry of the APPLs produced also differed. S. viridosporus APPL was more lignin-like than that of S. badius and was slowly modified further over time, although no change in molecular weight distribution over time was observed. In contrast, S. badius APPL was less lignin-like and increased substantially in average molecular weight over time. Results indicated that differing mechanisms of lignin metabolism may exist in these two Streptomyces sp. strains. S. viridosporus APPL probably originates from the heart of the lignin and is released largely as the result of beta-ether cleavage and

  5. General analysis of the intermediate vector boson production in hadron collisions

    International Nuclear Information System (INIS)

    Rekalo, M.P.

    1981-01-01

    Polarization states of intermediate vector W(Z) bosons produced in inclusive hadron-hadron collisions, a 1 +a 2 →W(Z)+X, where a 1 a 2 are some nonpolarized hadrons, X is a nondetected particle assembly are studied in general. Since spatial parity in these processes is not preserved, polarized W(Z) boson production must be determined by 9 real structural functions, 4 of which characterize the effects of invariance violation in relation to spatial reflections. Three structural functions (P-odd) for pole W(Z) production mechanisms in the quantum chromodynamics should exactly equal zero (with regard to the gluon errors). The relation of the W(Z) matrix elements with the structural functions in different coordinate systems used while discussing the angular distributions of W(Z) boson decay products is established. Decription of the W(Z) polarization properties is analyzed in terms of the 4-vector of spin and tenzor of quadrupole polarization [ru

  6. Synthesis and reactions of deuterated 2-(alkylimino)-3-nitrosooxazolidines, 3-alkly-1-(2-hydroxyethyl)-1-nitrosoureas, and related compounds as possible intermediates in the aqueous decomposition of 3-alkyl-1-(2-chloroethyl)-1-nitrosoureas

    International Nuclear Information System (INIS)

    Lown, J.W.; Chauhan, S.M.S.

    1981-01-01

    Decomposition of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea-α-d 2 (CCNU-α-d 2 ) (7) in pH 7.2 phosphate buffer or of CINO-α-d 2 (9) or CHNU-α-d 2 (8) with the addition of chloride ion gives rise to the same spectrum of products, including deuterium-free acetaldehyde (29), a mixture of the two deuterio-2-chloroethanols, 2-hydroxy-2,2-dideuterioethyl cyclohexyl carbamates, and vinyl chloride containing one deuterium (i.e., opposite the results obtained in the corresponding reaction of BCNU-α-d 4 ). The products were identified and the number and position of the deuterium labels determined by GC/MS. The results are interpreted in terms of two decomposition pathways for CCNU. The first decomposition pathway operating for CCNU is via an intermediate-2-chloroethanediazohydroxide or the equivalent 2-chloroethyl cation in agreement with the results of other workers. The second pathway may involve reversible conversion of CCNU-α-d 2 (7) to CINO-α-d 2 (9) and then ring opening of the latter to CHNU-α-d 2 (8). Independent decomposition of 8 provides evidence for its conversion to a 1.1-dideuterio-2-hydroxyethanediazohydroxide (41) leading to the isolated carbamates 36 and 44. The intermediacy of species 41 may account for the formation of 2-hydroxyethylated nucleosides observed when (2-chloroethyl)nitrosoureas react with DNA. An alternative ring-opening reaction of 9 leads to a 2-hydroxydiazoethyl cyclohexylcarbamate species (37), elimination of which and attack by halide ion may account for the vinyl halide species formed. Further evidence in support of these competing pathways employing additional specifically deuterated intermediates is described and discussed

  7. Bioethanol production from intermediate products of sugar beet processing with different types of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    J. Ranković

    2009-01-01

    Full Text Available The use of biofuels as an alternative to fossil fuels has expanded in the last few decades. The aim of this study was to examine the application of different strains and forms of Saccharomyces cerevisiae for raw, thin and thick juice fermentation in order to produce bioethanol. According to the obtained results the strain applied in the form of pressed blocks with 70 % w/w moisture, attained higher value of the specific growth rate and lower value of ethanol yield in comparison with strains applied in dried form. In all culture media attained efficiency of sugar utilization was at least from 98-99 % w/w. Maximum productivity was achieved around 30th hour of fermentation and amounted ≈1.8 g l-1 h-1 for all applied yeast strains. Therefore, optimal duration of the process in technical and economic terms should be considered.

  8. Production of alkyl esters from macaw palm oil by a sequential hydrolysis/esterification process using heterogeneous biocatalysts: optimization by response surface methodology.

    Science.gov (United States)

    Bressani, Ana Paula P; Garcia, Karen C A; Hirata, Daniela B; Mendes, Adriano A

    2015-02-01

    The present study deals with the enzymatic synthesis of alkyl esters with emollient properties by a sequential hydrolysis/esterification process (hydroesterification) using unrefined macaw palm oil from pulp seeds (MPPO) as feedstock. Crude enzymatic extract from dormant castor bean seeds was used as biocatalyst in the production of free fatty acids (FFA) by hydrolysis of MPPO. Esterification of purified FFA with several alcohols in heptane medium was catalyzed by immobilized Thermomyces lanuginosus lipase (TLL) on poly-hydroxybutyrate (PHB) particles. Under optimal experimental conditions (mass ratio oil:buffer of 35% m/m, reaction temperature of 35 °C, biocatalyst concentration of 6% m/m, and stirring speed of 1,000 rpm), complete hydrolysis of MPPO was reached after 110 min of reaction. Maximum ester conversion percentage of 92.4 ± 0.4% was reached using hexanol as acyl acceptor at 750 mM of each reactant after 15 min of reaction. The biocatalyst retained full activity after eight successive cycles of esterification reaction. These results show that the proposed process is a promising strategy for the synthesis of alkyl esters of industrial interest from macaw palm oil, an attractive option for the Brazilian oleochemical industry.

  9. An analysis of the changes on intermediate products during the thermal processing of black garlic.

    Science.gov (United States)

    Yuan, Heng; Sun, Linjuan; Chen, Min; Wang, Jun

    2018-01-15

    The thermal processing of black garlic was simulated. Fresh garlic was incubated at 55°C with 80% humidity and sampled every 5 or 10days. The changes in relevant products were as follows: the fructan content was decreased by 84.79%, and the fructose content was increased by 508.11%. The contents of Maillard reaction intermediate products were first increased and then decreased. The colour of garlic gradually became dark and the pH decreased from 6.13 to 4.00. By analyzing these changes, the mechanism of black garlic formation and the changes on the Maillard reaction were revealed. The sweetness of black garlic resulted mainly from the fructose that was produced, and the black colour was largely due to the Maillard reaction between fructose/glucose and amino acids. An understanding of this process is useful to explain the formation mechanism of black garlic and could lead to better control of the quality of black garlic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Production and muonic decay of the Z0 intermediate vector boson in the UA1 experiment

    International Nuclear Information System (INIS)

    Leuchs, R.

    1988-01-01

    In the years 1982 to 1985 the intermediate bosons W +- and Z 0 were detected in all the leptonic decay channels. In the present work we examined experimentally the production of the Z 0 in proton-antiproton collisions, followed by decay of the Z 0 into two muons. At present this is possible only in the UA1 experiment. Within the framework of this work I was initially responsible for the correct data readout from the muon detector. For this purpose it was necessary to build a monitoring system based on microprocessors, which could be used to monitor and test our apparatus. This monitoring system contains numerous programs for the diagnosis of the equipment. In the analysis I first selected the Z 0 events in the runs of 1984 and 1985, and then determined the efficiency of this selection. I also participated in setting up the p/sub t//sup μ/ > 15 GeV/c selection. Then the Z 0 sample was tested for completeness, and the background calculated anew. The methods of energy balance and mass fitting were refined and systematized. Thus the production properties and the mass of the Z 0 could be determined for the first time for the entire measurement period of the UA1. The determination of the parameters of the standard model was done by also including the results of analyses from other decay channels of the W and Z bosons. 149 refs., 60 figs., 14 tabs

  11. Production of reactive nitrogen intermediates (RNI) by peritoneal macrophages from rats with experimental autoimmune prostatitis (EAP).

    Science.gov (United States)

    Orsilles, M A; Depiante-Depaoli, M

    1995-08-01

    Peritoneal macrophages from experimental autoimmune prostatitis (EAP) rats were examined for their capacity to secrete reactive nitrogen intermediates (RNI), measured by the release of nitrite (NO2-). Under basal conditions, there was a significant increase of NO2- secretion by cells from autoimmune rats in relation to resident cells. After stimulation in vitro with lipopolysaccharide (LPS), the NO2- production was higher in cells from autoimmune rats compared to treated and nontreated controls. The NO2- production was dependent upon the presence of L-arginine in the culture medium. The addition of L-NG-monomethyl arginine, an inhibitor of nitric oxide synthesis, to the medium reduced the amount of measurable NO2-. Kinetic studies in cells from EAP rats showed that in basal conditions there was an significant release of NO2- at day 7 of immunization that was maintained during the whole period studied. After LPS stimulation, there was a similar behavior and maximum values were reached at day 28 of immunization. These results, together with the lesion observed in the prostate gland, suggest that RNI may be of pathogenic importance in the development of early tissue inflammation and autoimmune disease of the prostate.

  12. APA-style human milk fat analogue from silkworm pupae oil: Enzymatic production and improving storage stability using alkyl caffeates.

    Science.gov (United States)

    Liu, Xi; Wang, Xudong; Pang, Na; Zhu, Weijie; Zhao, Xingyu; Wang, Fangqin; Wu, Fuan; Wang, Jun

    2015-12-08

    Silkworm pupae oil derived from reeling waste is a rich source of α-linolenic acid (ALA), which has multipal applications. ALAs were added in sn-1, 3 positions in a triacylglycerol (TAG) to produce an APA-human milk fat analogues (APA-HMFAs, A: α-linolenic acid, P: palmitic acid). The optimum condition is that tripalmitin to free fatty acids of 1:12 (mole ratio) at 65 °C for 48 h using lipase Lipozyme RM IM. Results show that, the major TAG species that comprised APA-HMFAs were rich in ALA and palmitic acid, which contained 64.52% total unsaturated fatty acids (UFAs) and 97.05% PA at the sn-2 position. The melting point of APA was -27.5 °C which is much lower than tripalmitin (40.5 °C) indicating more plastic character. In addition, the practical application of alkyl caffeates as liposoluble antioxidants in APA was developed. Alkyl caffeate showed a superior IC50 (1.25-1.66 μg/mL) compared to butyl hydroxy anisd (1.67 μg/mL) and L-ascorbic acid-6-palmitate (L-AP) (1.87 μg/mL) in DPPH analysis. The addition of ethyl caffeate to oil achieved a higher UFAs content (73.58%) at high temperatures. Overall, APA was obtained from silkworm pupae oil successfully, and the addition of caffeates extended storage ranges for APA-HMFAs.

  13. Regioselectivity in Reactions between Bis(2-benzothiazolyl)ketone and Vinyl Grignard Reagents: C- versus O-alkylation-Part III.

    Science.gov (United States)

    Boga, Carla; Bordoni, Silvia; Casarin, Lucia; Micheletti, Gabriele; Monari, Magda

    2018-01-15

    The reaction between bis(2-benzothiazolyl)ketone and vinyl Grignard reagents bearing different substituents on the vinyl moiety gave the product derived from attack on the carbonylic carbon- and/or oxygen-atom. The regioselectivity of the attack depends on the kind of substituents bound to the vinylic carbon atoms and on their relative position. The reaction between vinylmagnesium bromide and 2-methyl-1-propenylmagnesium bromide was carried out under different experimental conditions and in the presence of radical scavengers. The results indicate a plausible mechanistic pathway involving radical intermediates in the case of O -alkylation, but a polar ones in the case of classic C -alkylation. This agrees with our previous reports indicating a key role played by the delocalization ability of the substituents bound to the carbonyl group in driving the regioselectivity of the vinylmagnesium bromide attack towards O -alkylation. Further support of this was obtained by diffractometric analysis of four distinct bis(heteroaryl)ketones.

  14. Growth/no growth models for Zygosaccharomyces rouxii associated with acidic, sweet intermediate moisture food products.

    Science.gov (United States)

    Marvig, C L; Kristiansen, R M; Nielsen, D S

    2015-01-02

    The most notorious spoilage organism of sweet intermediate moisture foods (IMFs) is Zygosaccharomyces rouxii, which can grow at low water activity, low pH and in the presence of organic acids. Together with an increased consumer demand for preservative free and healthier food products with less sugar and fat and a traditionally long self-life of sweet IMFs, the presence of Z. rouxii in the raw materials for IMFs has made assessment of the microbiological stability a significant hurdle in product development. Therefore, knowledge on growth/no growth boundaries of Z. rouxii in sweet IMFs is important to ensure microbiological stability and aid product development. Several models have been developed for fat based, sweet IMFs. However, fruit/sugar based IMFs, such as fruit based chocolate fillings and jams, have lower pH and aw than what is accounted for in previously developed models. In the present study growth/no growth models for acidified sweet IMFs were developed with the variables aw (0.65-0.80), pH (2.5-4.0), ethanol (0-14.5% (w/w) in water phase) and time (0-90 days). Two different strains of Z. rouxii previously found to show pronounced resistance to the investigated variables were included in model development, to account for strain differences. For both strains data sets with and without the presence of sorbic acid (250 ppm on product basis) were built. Incorporation of time as an exploratory variable in the models gave the possibility to predict the growth/no growth boundaries at each time between 0 and 90 days without decreasing the predictive power of the models. The influence of ethanol and aw on the growth/no growth boundary of Z. rouxii was most pronounced in the first 30 days and 60 days of incubation, respectively. The effect of pH was almost negligible in the range of 2.5-4.0. The presence of low levels of sorbic acid (250 ppm) eliminated growth of both strains at all conditions tested. The two strains tested have previously been shown to have

  15. Camphor-10-sulfonic acid catalyzed condensation of 2-naphthol with aromatic/aliphatic aldehydes to 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes

    Directory of Open Access Journals (Sweden)

    Kundu Kshama

    2014-01-01

    Full Text Available (±-Camphor-10-sulfonic acid (CSA catalyzed condensation of 2-naphthol with both aliphatic/aromatic aldehydes at 80°C yielded 14-alkyl/aryl-dibenzoxanthenes as the sole product in high yields. However, the same condensation with benzaldehyde at 25°C afforded a mixture of intermediate 1,1-bis-(2-hydroxynaphthylphenylmethane and 14-phenyl-dibenzoxanthene while the condensation with aliphatic aldehydes at 25°C furnished the corresponding 14-alkyl-dibenzoxanthenes as the sole product. Moreover, condensation of 2-naphthol with aromatic/aliphatic aldehydes with low catalyst loading (2 mol% was greatly accelerated under microwave irradiation to afford the corresponding 14-aryl/alkyl-dibenzoxanthenes as the sole product in high yields.

  16. Helicity amplitudes of di-photons production at the LHC with scalar unparticles intermediate states

    Energy Technology Data Exchange (ETDEWEB)

    Aliane, I.; Mebarki, N.; Haouchine, M. [Laboratoire de Physique Mathematique et Subatomique, Mentouri University, Constantine (Algeria)

    2012-06-27

    The helecity amplitudes of the subprocess gg{yields}{gamma}{gamma} via scalar unparticles intermediate states are calculated. The differential cross section is compared to that of the standard model. Phenomenological implications are also discussed.

  17. Criegee Intermediates: What Direct Production and Detection Can Teach Us About Reactions of Carbonyl Oxides

    Science.gov (United States)

    Taatjes, Craig A.

    2017-05-01

    The carbonyl oxide intermediates in the ozonolysis of alkenes, often known as Criegee intermediates, are potentially important reactants in Earth's atmosphere. For decades, careful analysis of ozonolysis systems was employed to derive an understanding of the formation and reactions of these species. Recently it has proved possible to synthesize at least some of these intermediates separately from ozonolysis, and hence to measure their reaction kinetics directly. Direct measurements have allowed new or more detailed understanding of each type of gas-phase reaction that carbonyl oxides undergo, often acting as a complement to highly detailed ozonolysis experiments. Moreover, the use of direct characterization methods to validate increasingly accurate theoretical investigations can enhance their impact well beyond the set of specific reactions that have been measured. Reactions that initiate particles or fuel their growth could be a new frontier for direct measurements of Criegee intermediate chemistry.

  18. Production and Characterization of Polymeric Lignin Degradation Intermediates from Two Different Streptomyces spp. †

    OpenAIRE

    Borgmeyer, Jeffry R.; Crawford, Don L.

    1985-01-01

    Previous investigations have identified a quantitatively major intermediate of lignin degradation by Streptomyces viridosporus. The intermediate, a modified lignin polymer, acid-precipitable polymeric lignin (APPL), is released as a water-soluble catabolite and has been recovered in amounts equivalent to 30% of the lignin originally present in a corn stover lignocellulose substrate after degradation by this actinomycete. In the present work, APPLs were collected at various time intervals from...

  19. Interfce alkylation of ethyldiphenylphosphinylacetate

    International Nuclear Information System (INIS)

    Yarkevich, A.N.; Tsvetkov, E.N.

    1994-01-01

    The paper deals with the alkylation of the methyline group of ethyldiphenylphosphinylacetate (1) by different alkylating agents in the presence of Cs 2 CO 3 . In all cases the application of Cs 2 CO 3 results in a significant increase of reaction rate. 10 refs., 3 tabs

  20. Transformation and products of captopril with humic constituents during laccase-catalyzed oxidation: Role of reactive intermediates.

    Science.gov (United States)

    Du, Penghui; Zhao, He; Liu, Chenming; Huang, Qingguo; Cao, Hongbin

    2016-12-01

    The transformation of captopril (CAP), a widely-used thiol drug, was studied with the presence of dissolved model humic constituents (HCs) in a laccase-catalyzed system. Reaction products were analyzed by ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry and condensed fukui function computation. CAP reacted with different model HCs in the enzymatic system for 1 h, ranging from 75% (syringic acid) to 96% (p-coumaric acid). In the absence of HCs, only 15% of CAP was removed through self-coupling. The presence of HCs apparently changed the transformation of CAP in aqueous environment, and the HC reactive intermediates played an important role. First, during laccase catalysis, HCs with different structures were oxidized to produce reactive intermediates, including phenoxyl radical cation, ortho-, and para-quinone intermediates. Second, these intermediates were readily attacked by CAP via nucleophilic reactions, forming C-S-C covalent conjugates. More importantly, the standard reduction potential of these intermediates is a critical parameter, as PCA showed the highest reactivity to the nucleophilic addition reaction with CAP by forming phenoxy radical cations. While SYR showed the least reactivity due to the formation of para-quinone intermediates. Therefore, the functional groups on HCs could greatly influence the cross-coupling with CAP, as well as the type and stability of the coupling products. This work clearly demonstrated the transformation of CAP and other thiol drugs with the presence of HCs in aqueous environment, which is similar to the natural humification process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Production of cephalosporin intermediates by feeding adipic acid to recombinant Penicillium chrysogenum strains expressing ring expansion activity.

    Science.gov (United States)

    Crawford, L; Stepan, A M; McAda, P C; Rambosek, J A; Conder, M J; Vinci, V A; Reeves, C D

    1995-01-01

    We demonstrate a novel and efficient bioprocess for production of the cephalosporin intermediates, 7-aminocephalosporanic acid (7-ACA) or 7-amino deacetoxycephalosporanic acid (7-ADCA). The Streptomyces clavuligerus expandase gene or the Cephalosporium acremonium expandase-hydroxylase gene, with and without the acetyltransferase gene, were expressed in a penicillin production strain of Penicillium chrysogenum. Growth of these transformants in media containing adipic acid as the side chain precursor resulted in efficient production of cephalosporins having an adipyl side chain, proving that adipyl-6-APA is a substrate for either enzyme in vivo. Strains expressing expandase produced adipyl-7-ADCA, whereas strains expressing expandase-hydroxylase produced both adipyl-7-ADCA and adipyl-7-ADAC (aminodeacetylcephalosporanic acid). Strains expressing expandase-hydroxylase and acetyltransferase produced adipyl-7-ADCA, adipyl-7-ADAC and adipyl-7-ACA. The adipyl side chain of these cephalosporins was easily removed with a Pseudomonas-derived amidase to yield the cephalosporin intermediates.

  2. Alk3 controls nephron number and androgen production via lineage-specific effects in intermediate mesoderm.

    Science.gov (United States)

    Di Giovanni, Valeria; Alday, Adrian; Chi, Lijun; Mishina, Yuji; Rosenblum, Norman D

    2011-07-01

    The mammalian kidney and male reproductive system are both derived from the intermediate mesoderm. The spatial and temporal expression of bone morphogenetic protein (BMP) 2 and BMP4 and their cognate receptor, activin like kinase 3 (ALK3), suggests a functional role for BMP-ALK3 signaling during formation of intermediate mesoderm-derivative organs. Here, we define cell autonomous functions for Alk3 in the kidney and male gonad in mice with CRE-mediated Alk3 inactivation targeted to intermediate mesoderm progenitors (Alk3(IMP null)). Alk3-deficient mice exhibit simple renal hypoplasia characterized by decreases in both kidney size and nephron number but normal tissue architecture. These defects are preceded by a decreased contribution of Alk3-deleted cells to the metanephric blastema and reduced expression of Osr1 and SIX2, which mark nephron progenitor cells. Mutant mice are also characterized by defects in intermediate mesoderm-derived genital tissues with fewer mesonephric tubules and testicular Leydig cells, epithelial vacuolization in the postnatal corpus epididymis, and decreased serum testosterone levels and reduced fertility. Analysis of ALK3-dependent signaling effectors revealed lineage-specific reduction of phospho-p38 MAPK in metanephric mesenchyme and phospho-SMAD1/5/8 in the testis. Together, these results demonstrate a requirement for Alk3 in distinct progenitor cell populations derived from the intermediate mesoderm.

  3. LABORATORY-SCALE PRODUCTION OF ADU GELS BY EXTERNAL GELATION FOR AN INTERMEDIATE HTGR NUCLEAR

    Directory of Open Access Journals (Sweden)

    S Simbolon

    2015-03-01

    Full Text Available LABORATORY-SCALE PRODUCTION OF ADU GELS BY EXTERNAL GELATION FOR AN INTERMEDIATE HTGR NUCLEAR. The The aim of this research is to produce thousands of microsphere ADU (Ammonium Diuranate gels by using external gelation for an intermediate HTGR (High Temperature Gas-cooled Reactor nuclear fuel in laboratory-scale. Microsphere ADU gels were based on sol-solution which was made from a homogeneous mixture of ADUN (Acid Deficient Uranyl Nitrate which was containing uranyl ion in high concentration, a water soluble organic compound PVA (Polyvinyl Alcohol and THFA (Tetrahydrofurfuryl Alcohol. The simple unified home made laboratory experimental machine was developed to replace test tube experiment method which was once used due to a tiny amount of microsphere ADU gels produced. It consists of four main parts: tank filled sol-solution connecting to peristaltic pump and vibrating nozzle, preliminary gelation and gelation column. The machine has successfully converted 150 mL sol-solution into thousands of drops which produced 120 - 130 drops in each minute in steady state in ammonia gas free sector. Preliminary gelation reaction was carried out in ammonia gas sector where drops react with ammonia gas in a bat an eye followed by gelation reaction in column containing ammonia solution 7 M. In ageing process, ADU gels were collected and submerged into a vessel containing ammonia solution which was shaken for 1 hour in a shaker device. Isopropyl alcohol (90% solution was used to wash ADU gels and a digital camera was used to measured spherical form of ADU gels. Diameters in spherical spheroid form were found between 1.8 mm until 2.2 mm. The spherical purity of ADU gels were 10% - 20% others were oblate, prolate spheroid and microsphere which have hugetiny of dimples on the surface.   PRODUKSI GEL ADU SKALA LABORATORIUM DENGAN MENGGUNAKAN GELASI EKSTERNAL UNTUK BAHAN BAKAR ANTARA HTGR. Penelitian ini bertujuan untuk membuat ribuan gel bulat ADU (Ammonium

  4. Hydride Transfer versus Deprotonation Kinetics in the Isobutane–Propene Alkylation Reaction: A Computational Study

    Science.gov (United States)

    2017-01-01

    The alkylation of isobutane with light alkenes plays an essential role in modern petrochemical processes for the production of high-octane gasoline. In this study we have employed periodic DFT calculations combined with microkinetic simulations to investigate the complex reaction mechanism of isobutane–propene alkylation catalyzed by zeolitic solid acids. Particular emphasis was given to addressing the selectivity of the alkylate formation versus alkene formation, which requires a high rate of hydride transfer in comparison to the competitive oligomerization and deprotonation reactions resulting in catalyst deactivation. Our calculations reveal that hydride transfer from isobutane to a carbenium ion occurs via a concerted C–C bond formation between a tert-butyl fragment and an additional olefin, or via deprotonation of the tert-butyl fragment to generate isobutene. A combination of high isobutane concentration and low propene concentration at the reaction center favor the selective alkylation. The key reaction step that has to be suppressed to increase the catalyst lifetime is the deprotonation of carbenium intermediates that are part of the hydride transfer reaction cycle. PMID:29226012

  5. Hydride Transfer versus Deprotonation Kinetics in the Isobutane-Propene Alkylation Reaction: A Computational Study.

    Science.gov (United States)

    Liu, Chong; van Santen, Rutger A; Poursaeidesfahani, Ali; Vlugt, Thijs J H; Pidko, Evgeny A; Hensen, Emiel J M

    2017-12-01

    The alkylation of isobutane with light alkenes plays an essential role in modern petrochemical processes for the production of high-octane gasoline. In this study we have employed periodic DFT calculations combined with microkinetic simulations to investigate the complex reaction mechanism of isobutane-propene alkylation catalyzed by zeolitic solid acids. Particular emphasis was given to addressing the selectivity of the alkylate formation versus alkene formation, which requires a high rate of hydride transfer in comparison to the competitive oligomerization and deprotonation reactions resulting in catalyst deactivation. Our calculations reveal that hydride transfer from isobutane to a carbenium ion occurs via a concerted C-C bond formation between a tert -butyl fragment and an additional olefin, or via deprotonation of the tert -butyl fragment to generate isobutene. A combination of high isobutane concentration and low propene concentration at the reaction center favor the selective alkylation. The key reaction step that has to be suppressed to increase the catalyst lifetime is the deprotonation of carbenium intermediates that are part of the hydride transfer reaction cycle.

  6. Isobutane alkylation over solid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kozorezov, Y.I.; Lisin, V.I.

    1979-05-01

    Commercial alumina modified with 6Vertical Bar3< by wt boron trifluoride was active in isobutane alkylation with ethylene in a flow reactor at 5:1 isobutane-ethylene and 5-20 min reaction time. The reaction rate was first-order in ethylene and increased with increasing temperature (20/sup 0/-80/sup 0/C) and ethylene pressure (0.2-3 atm). The calculated activation energy was 8.4 kj. Kinetic data and the activity of tert.-butyl chloride, but not ethyl chloride as alkylating agents in place of ethylene suggested a carbonium-ion chain mechanism involving both surface and gas-phase reactions. The ethylene-based yield of the alkylate decreased from 132 to 41Vertical Bar3< by wt after nine hours on stream, and its bromine number increased from 0.2 to 1 g Br/sub 2//100 ml. This inhibition was attributed to adsorption on the active acidic sites of the reaction products, particularly C/sub 10//sup +/ olefins. Catalyst stabilization could probably be achieved by selecting an appropriate solvent that would continuously desorb the inhibiting products from the catalyst surface.

  7. Infrared Analysis of Combustion Products and Intermediates of Hydrocarbon Combustion for Several Species

    Science.gov (United States)

    White, Allen; Devasher, Rebecca

    2015-06-01

    Hydrocarbons, especially large ones such as isooctane, have infrared active species that give insight into combustion stoichiometry and temperature. Here a Fourier-transform infrared spectrometer is utilized to study the IR active species for a number of stociometric conditions for several fuels including isooctane, kerosene, and ethanol. Special attention is given to intermediate species in different flame regions.

  8. Nitrogen requirements at bulb initiation for production of intermediate-day onions

    Science.gov (United States)

    The effect of nitrogen application on growth, nitrogen (N) uptake, yield, and quality of intermediate-day onion (Allium cepa L. ‘Guimar’) was evaluated in the field in southern Portugal. Plants were fertilized with 30 kg/ha N at transplanting, 10 kg/ha N at 29 days after transplanting (DAT) during ...

  9. Single intermediate vector boson production in $e^{+}e^{-}$ collisions at $\\sqrt{s}$ = 183 - 209 GeV

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, D; Barker, G J; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N; Benvenuti, A C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F; Chapkin, M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J; Gandelman, M; García, C; Gavillet, P; Gazis, E; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E C; Kernel, G; Kersevan, B P; Kerzel, U; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, R; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Pozdnyakov, V; Pukhaeva, N; Pullia, A; Rames, J; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Sander, C; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sisakian, A; Smadja, G; Smirnova, O; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zintchenko, A; Zupan, M

    2006-01-01

    The production of single charged and neutral intermediate vector bosons in e+e- collisions has been studied in the data collected by the DELPHI experiment at LEP at centre-of-mass energies between 183 and 209 GeV, corresponding to an integrated luminosity of about 640 pb^{-1}. The measured cross-sections for the reactions, determined in limited kinematic regions, are in agreement with the Standard Model predictions.

  10. Single Intermediate Vector Boson Production in $e^+ e^-$ collisions at $\\sqrt{s}$ = 183 and 189 GeV

    CERN Document Server

    Abreu, P.; Adye, T.; Adzic, P.; Ajinenko, I.; Albrecht, Z.; Alderweireld, T.; Alekseev, G.D.; Alemany, R.; Allmendinger, T.; Allport, P.P.; Almehed, S.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Anassontzis, E.G.; Andersson, P.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.D.; Arnoud, Y.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barao, F.; Barbiellini, G.; Barbier, R.; Bardin, Dmitri Yu.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.H.; Begalli, M.; Behrmann, A.; Bellunato, T.; Belokopytov, Yu.; Benekos, N.C.; Benvenuti, A.C.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bilenky, Mikhail S.; Bloch, D.; Blom, H.M.; Bol, L.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Bosio, C.; Botner, O.; Boudinov, E.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bozovic, I.; Bozzo, M.; Bracko, M.; Branchini, P.; Brenner, R.A.; Bruckman, P.; Brunet, J.M.; Bugge, L.; Buschmann, P.; Caccia, M.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Carroll, L.; Caso, C.; Castillo Gimenez, M.V.; Cattai, A.; Cavallo, F.R.; Chapkin, M.; Charpentier, P.; Checchia, P.; Chelkov, G.A.; Chierici, R.; Chliapnikov, P.; Chochula, P.; Chorowicz, V.; Chudoba, J.; Cieslik, K.; Collins, P.; Contri, R.; Cortina, E.; Cosme, G.; Cossutti, F.; Costa, M.; Crawley, H.B.; Crennell, D.; Croix, J.; Crosetti, G.; Cuevas Maestro, J.; Czellar, S.; D'Hondt, J.; Dalmau, J.; Davenport, M.; Da Silva, W.; Della Ricca, G.; Delpierre, P.; Demaria, N.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Min, A.; De Paula, L.; Dijkstra, H.; Di Ciaccio, L.; Doroba, K.; Dracos, M.; Drees, J.; Dris, M.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Engel, J.P.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferrer-Ribas, E.; Ferro, F.; Firestone, A.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fontanelli, F.; Franek, B.; Frodesen, A.G.; Fruhwirth, R.; Fulda-Quenzer, F.; Fuster, J.; Galloni, A.; Gamba, D.; Gamblin, S.; Gandelman, M.; Garcia, C.; Gaspar, C.; Gaspar, M.; Gasparini, U.; Gavillet, P.; Gazis, Evangelos; Gele, D.; Geralis, T.; Ghodbane, N.; Gil Botella, Ines; Glege, F.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Gonzalez Caballero, I.; Gopal, G.; Gorn, L.; Gouz, Yu.; Gracco, V.; Grahl, J.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hahn, F.; Hahn, S.; Haider, S.; Hallgren, A.; Hamacher, K.; Hansen, J.; Harris, F.J.; Haug, S.; Hauler, F.; Hedberg, V.; Heising, S.; Hernandez, J.J.; Herquet, P.; Herr, H.; Hertz, O.; Higon, E.; Holmgren, S.O.; Holt, P.J.; Hoorelbeke, S.; Houlden, M.; Hrubec, J.; Hughes, G.J.; Hultqvist, K.; Jackson, John Neil; Jacobsson, R.; Jalocha, P.; Jarlskog, C.; Jarlskog, G.; Jarry, P.; Jean-Marie, B.; Jeans, D.; Johansson, Erik Karl; Jonsson, P.; Joram, C.; Juillot, P.; Jungermann, L.; Kapusta, Frederic; Karafasoulis, K.; Katsanevas, S.; Katsoufis, E.C.; Keranen, R.; Kernel, G.; Kersevan, B.P.; Khokhlov, Yu.A.; Khomenko, B.A.; Khovanski, N.N.; Kiiskinen, A.; King, B.; Kinvig, A.; Kjaer, N.J.; Klapp, O.; Kluit, P.; Kokkinias, P.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krammer, M.; Kriznic, E.; Krumstein, Z.; Kubinec, P.; Kucharczyk, M.; Kurowska, J.; Lamsa, J.W.; Laugier, J.P.; Leder, G.; Ledroit, Fabienne; Leinonen, L.; Leisos, A.; Leitner, R.; Lenzen, G.; Lepeltier, V.; Lesiak, T.; Lethuillier, M.; Libby, J.; Liebig, W.; Liko, D.; Lipniacka, A.; Lippi, I.; Loken, J.G.; Lopes, J.H.; Lopez, J.M.; Lopez-Fernandez, R.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Mahon, J.R.; Maio, A.; Malek, A.; Maltezos, S.; Malychev, V.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Marti i Garcia, S.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Matthiae, G.; Mazzucato, F.; Mazzucato, M.; McCubbin, M.; McKay, R.; McNulty, R.; McPherson, G.; Merle, E.; Meroni, C.; Meyer, W.T.; Miagkov, A.; Migliore, E.; Mirabito, L.; Mitaroff, W.A.; Mjoernmark, U.; Moa, T.; Moch, M.; Monig, Klaus; Monge, M.R.; Montenegro, J.; Moraes, D.; Morettini, P.; Morton, G.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.M.; Murray, W.J.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.L.; Nawrocki, K.; Negri, P.; Nemecek, S.; Neufeld, N.; Nicolaidou, R.; Niezurawski, P.; Nikolenko, M.; Nomokonov, V.; Nygren, A.; Obraztsov, V.; Olshevski, A.G.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Pain, R.; Paiva, R.; Palacios, J.; Palka, H.; Papadopoulou, T.D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Pavel, T.; Pegoraro, M.; Peralta, L.; Perepelitsa, V.; Pernicka, M.; Perrotta, A.; Petridou, C.; Petrolini, A.; Phillips, H.T.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Privitera, P.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Ragazzi, S.; Rahmani, H.; Ratoff, P.N.; Read, Alexander L.; Rebecchi, P.; Redaelli, Nicola Giuseppe; Regler, M.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.B.; Resvanis, L.K.; Richard, F.; Ridky, J.; Rinaudo, G.; Ripp-Baudot, Isabelle; Romero, A.; Ronchese, P.; Rosenberg, E.I.; Rosinsky, P.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ruiz, A.; Saarikko, H.; Sacquin, Y.; Sadovsky, A.; Sajot, G.; Salmi, L.; Salt, J.; Sampsonidis, D.; Sannino, M.; Savoy-Navarro, A.; Schwanda, C.; Schwemling, P.; Schwering, B.; Schwickerath, U.; Scuri, Fabrizio; Seager, P.; Sedykh, Y.; Segar, A.M.; Sekulin, R.; Sette, G.; Shellard, R.C.; Siebel, M.; Simard, L.; Simonetto, F.; Sisakian, A.N.; Smadja, G.; Smirnov, N.; Smirnova, O.; Smith, G.R.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Spiriti, E.; Stanescu, C.; Stanitzki, M.; Stevenson, K.; Stocchi, A.; Strauss, J.; Strub, R.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Tabarelli, T.; Taffard, A.; Tegenfeldt, F.; Terranova, F.; Timmermans, Jan; Tinti, N.; Tkatchev, L.G.; Tobin, M.; Todorova, S.; Tome, B.; Tonazzo, A.; Tortora, L.; Tortosa, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Ullaland, O.; Uvarov, V.; Valenti, G.; Vallazza, E.; Van Dam, Piet; Van den Boeck, W.; Van Eldik, J.; Van Lysebetten, A.; Van Remortel, N.; Van Vulpen, I.; Vegni, G.; Ventura, L.; Venus, W.; Verbeure, F.; Verdier, P.; Verlato, M.; Vertogradov, L.S.; Verzi, V.; Vilanova, D.; Vitale, L.; Vlasov, E.; Vodopianov, A.S.; Voulgaris, G.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.H.; Wilkinson, G.R.; Winter, M.; Witek, M.; Wolf, G.; Yi, J.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zevgolatakos, E.; Zimine, N.I.; Zintchenko, A.; Zoller, P.; Zumerle, G.; Zupan, M.; Krammer, Manfred

    2001-01-01

    The cross-sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52~pb$^{-1}$ and 154~pb$^{-1}$ collected by the DELPHI experiment at centre-of-mass energies of 182.6~GeV and 188.6~GeV, respectively. The cross-sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels.

  11. Very backward π0- and eta0-production by proton projectiles on deuterium target at intermediate energies

    International Nuclear Information System (INIS)

    Berthet, P.; Frascaria, R.; Didelez, J.P.

    1984-01-01

    The production of π 0 and eta 0 mesons in the reactions pd→π 0 tau and pd→eta 0 tau has been studied at very backward angles for kinetic proton energies Tsub(p) ranging from 0.92 to 2.6 GeV. The excitation functions at phisub(π) = phisub(eta) = 180 0 display large structures which might be related to baryonic (Δ and N*) excitations in the intermediate state

  12. Mono- and Di-Alkylation Processes of DNA Bases by Nitrogen Mustard Mechlorethamine.

    Science.gov (United States)

    Larrañaga, Olatz; de Cózar, Abel; Cossío, Fernando P

    2017-12-06

    The reactivity of nitrogen mustard mechlorethamine (mec) with purine bases towards formation of mono- (G-mec and A-mec) and dialkylated (AA-mec, GG-mec and AG-mec) adducts has been studied using density functional theory (DFT). To gain a complete overview of DNA-alkylation processes, direct chloride substitution and formation through activated aziridinium species were considered as possible reaction paths for adduct formation. Our results confirm that DNA alkylation by mec occurs via aziridine intermediates instead of direct substitution. Consideration of explicit water molecules in conjunction with polarizable continuum model (PCM) was shown as an adequate computational method for a proper representation of the system. Moreover, Runge-Kutta numerical kinetic simulations including the possible bisadducts have been performed. These simulations predicted a product ratio of 83:17 of GG-mec and AG-mec diadducts, respectively. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Graft copolymerization of a series of alkyl acrylates and alkyl methacrylates onto polyethylene

    International Nuclear Information System (INIS)

    Zurakowska-Orszagh, J.; Soerjosoeharto, K.; Busz, W.; Oldziejewski, J.

    1977-01-01

    Graft copolymerization of a series of alkyl acrylates and alkyl methacrylates into polyethylene of Polish production was investigated, using benzoyl peroxide as the initiator as well as preirradiation technique, namely ionizing radiation from a 60 Co γ-source. The effect of α-carbon methyl substituent of methacrylates as well as the influence of the length of alkyl chains in the ester groups of both series of monomers into the grafting process was observed. The ungrafted and some of the grafted polyethylene film obtained was studied by infrared spectrophotometry. (author)

  14. Biosynthesis of Alkyl Lysophosphatidic Acid by Diacylglycerol Kinases

    Science.gov (United States)

    Gellett, Amanda M.; Kharel, Yugesh; Sunkara, Manjula; Morris, Andrew J.; Lynch, Kevin R.

    2012-01-01

    Lysophosphatidic acid (LPA) designates a family of bioactive phosphoglycerides that differ in the length and degree of saturation of their radyl chain. Additional diversity is provided by the linkage of the radyl chain to glycerol: acyl, alkyl, or alk-1-enyl. Acyl-LPAs are the predominate species in tissues and biological fluids. Alkyl-LPAs exhibit distinct pharmacodynamics at LPA receptors, potently drive platelet aggregation, and contribute to ovarian cancer aggressiveness. Multiple biosynthetic pathways exist for alkyl-LPA production. Herein we report that diacylglycerol kinases (DGKs) contribute to cell-associated alkyl-LPA production involving phosphorylation of 1-alkyl-2-acetyl glycerol and document the biosynthesis of alkyl-LPA by DGKs in SKOV-3 ovarian cancer cells, specifically identifying the contribution of DGKα. Concurrently, we discovered that treating SKOV-3 ovarian cancer cell with a sphingosine analog stimulates conversion of exogenous 1-alkyl-2-acetyl glycerol to alkyl-LPA, indicating that DGKα contributes significantly to the production of alkyl-LPA in SKOV-3 cells and identifying cross-talk between the sphingolipid and glycerol lipid pathways. PMID:22627129

  15. INTEGRATING THE OUTPUT AND SUBSTITUTION EFFECTS OF PRODUCTION INTO THE INTERMEDIATE MICROECONOMICS TEXTBOOK

    OpenAIRE

    Ranjini L. Thaver

    2013-01-01

    Intermediate microeconomics textbooks employ indifference curve analysis to explain the income and substitution effects of a change in the price of a good x on the demand for it, holding other variables constant. Further, they demonstrate how the shape and slope of the demand curve changes depending on whether good x is defined as normal, inferior, or Giffen. This analysis in turn enables an evaluation of public policies aimed to increase consumer welfare. Unfortunately, these textbooks do no...

  16. The folly of using RCCs and RVUs for intermediate product costing.

    Science.gov (United States)

    Young, David W

    2007-04-01

    Two measures for computing the cost of intermediate projects--a ratio of cost to charges and relative value units--are highly flawed and can have serious financial implications for the hospitals that use them. Full-cost accounting, using the principles of activity-based costing, enables hospitals to measure their costs more accurately, both for competitive bidding purposes and to manage them more effectively.

  17. Effects of alkyl parabens on plant pathogenic fungi.

    Science.gov (United States)

    Ito, Shinsaku; Yazawa, Satoru; Nakagawa, Yasutaka; Sasaki, Yasuyuki; Yajima, Shunsuke

    2015-04-15

    Alkyl parabens are used as antimicrobial preservatives in cosmetics, food, and pharmaceutical products. However, the mode of action of these chemicals has not been assessed thoroughly. In this study, we determined the effects of alkyl parabens on plant pathogenic fungi. All the fungi tested, were susceptible to parabens. The effect of linear alkyl parabens on plant pathogenic fungi was related to the length of the alkyl chain. In addition, the antifungal activity was correlated with the paraben-induced inhibition of oxygen consumption. The antifungal activity of linear alkyl parabens likely originates, at least in part, from their ability to inhibit the membrane respiratory chain, especially mitochondrial complex II. Additionally, we determined that some alkyl parabens inhibit Alternaria brassicicola infection of cabbage. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Noncovalent DNA Binding Drives DNA Alkylation by Leinamycin. Evidence That the Z,E-5-(Thiazol-4-yl)-penta-2,4-dienone Moiety of the Natural Product Serves As An Atypical DNA Intercalator

    Science.gov (United States)

    Fekry, Mostafa I.; Szekely, Jozsef; Dutta, Sanjay; Breydo, Leonid; Zang, Hong; Gates, Kent S.

    2012-01-01

    Molecular recognition and chemical modification of DNA are important in medicinal chemistry, toxicology, and biotechnology. Historically, natural products have revealed many interesting and unexpected mechanisms for noncovalent DNA binding and covalent DNA modification. The studies reported here characterize the molecular mechanisms underlying the efficient alkylation of duplex DNA by the Streptomyces-derived natural product leinamycin. Previous studies suggested that alkylation of duplex DNA by activated leinamycin (2) is driven by noncovalent association of the natural product with the double helix. This is striking because leinamycin does not contain a classical noncovalent DNA-binding motif such as an intercalating unit, a groove binder, or a polycation. The experiments described here provide evidence that leinamycin is an atypical DNA-intercalating agent. A competition binding assay involving daunomycin-mediated inhibition of DNA alkylation by leinamycin provided evidence that activated leinamycin binds to duplex DNA with an apparent binding constant of approximately 4.3 ± 0.4 × 103 M−1. Activated leinamycin caused duplex unwinding and hydrodynamic changes in DNA-containing solutions that are indicative of DNA intercalation. Characterization of the reaction of activated leinamycin with palindromic duplexes containing 5'-CG and 5'-GC target sites, bulge-containing duplexes, and 5-methylcytosine-containing duplexes provided evidence regarding the orientation of leinamycin with respect to target guanine residues. The data allows construction of a model for the leinamycin-DNA complex suggesting how a modest DNA-binding constant combines with proper positioning of the natural product to drive efficient alkylation of guanine residues in the major groove of duplex DNA. PMID:21954957

  19. A catalytic reactor for the organocatalyzed enantioselective continuous flow alkylation of aldehydes.

    Science.gov (United States)

    Porta, Riccardo; Benaglia, Maurizio; Puglisi, Alessandra; Mandoli, Alessandro; Gualandi, Andrea; Cozzi, Pier Giorgio

    2014-12-01

    The use of immobilized metal-free catalysts offers the unique possibility to develop sustainable processes in flow mode. The challenging intermolecular organocatalyzed enantioselective alkylation of aldehydes was performed for the first time under continuous flow conditions. By using a packed-bed reactor filled with readily available supported enantiopure imidazolidinone, different aldehydes were treated with three distinct cationic electrophiles. In the organocatalyzed α-alkylation of aldehydes with 1,3-benzodithiolylium tetrafluoroborate, excellent enantioselectivities, in some cases even better than those obtained in the flask process (up to 95% ee at 25 °C), and high productivity (more than 3800 h(-1) ) were obtained, which thus shows that a catalytic reactor may continuously produce enantiomerically enriched compounds. Treatment of the alkylated products with Raney-nickel furnished enantiomerically enriched α-methyl derivatives, key intermediates for active pharmaceutical ingredients and natural products. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Reactivity patterns of transition metal hydrides and alkyls

    International Nuclear Information System (INIS)

    Jones, W.D. II.

    1979-05-01

    The complex PPN + CpV(CO) 3 H - (Cp=eta 5 -C 5 H 5 and PPN = (Ph 3 P) 2 ) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN + CpV(CO) 3 H - reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN + [CpV(C) 3 X] - and in some cases the binuclear bridging hydride PPN + [CpV(CO) 3 ] 2 H - . The borohydride salt PPN + [CpV(CO) 3 BH 4 ] - has also been prepared. The reaction between CpV(CO) 3 H - and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO) 3 H - . Sodium amalgam reduction of CpRh(CO) 2 or a mixture of CpRh(CO) 2 and CpCo(CO) 2 affords two new anions, PPN + [Cp 2 Rh 3 (CO) 4 ] - and PPN + [Cp 2 RhCo(CO) 2 ] - . CpMo(CO) 3 H reacts with CpMo(CO) 3 R (R=CH 3 ,C 2 H 5 , CH 2 C 6 H 5 ) at 25 to 50 0 C to produce aldehyde RCHO and the dimers [CpMo(CO) 3 ] 2 and [CpMo(CO) 2 ] 2 . In general, CpV(CO) 3 H - appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO) 3 H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO) 3 H - generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO) 3 H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species

  1. The light activated alkylation of glycine

    International Nuclear Information System (INIS)

    Knowles, H.S.

    2001-04-01

    The work contained in this thesis focuses on the light-initiated alkylation of the α-centre of glycine compounds. The elaboration of the glycines in this manner represents a versatile, clean and cost effective alternative to ionic routes to higher α-amino acids. Preliminary investigations demonstrated that a range of nitrogen protecting groups were compatible with the radical alkylation. A variety of solvents could also be used although solvents with easily removable hydrogen atoms were found to interfere with the alkylation. Furthermore, a number of photo-initiators were investigated and the use of di-tert-butyl peroxide was found to afford the desired phenylalanine products in up to 27% yield (54% based on recovered starting material) when toluene was used as the alkylating agent. A range of different precursor concentrations was investigated and it was found that the optimum concentration of the glycine precursor was 0.13 mol dm -3 ; the phenylalanine yields were reduced when the concentration was less than this value. Owing to the poor UV absorption by di-tert-butyl peroxide, benzophenone (an effective photosensitiser) was added to the reaction mixture and this was shown to increase the alkylation yields. The ratio of reagents which produced the highest yield of phenylalanine products was found to be 1 : 5 : 5 : 10 for glycine : di-tert-butyl peroxide : benzophenone : toluene. This produced the phenylalanine product in up to 37% yield (57% based on recovered starting material). A number of substituents. (e.g. F, Cl etc.) could be attached to the aromatic ring of the toluene alkylating agent, affording substituted phenylalanines in 5 - 36% under these conditions. The formation of chiral phenylalanine products was probed by reacting glycine precursors bearing chiral auxiliaries. However, low diastereoselectivities were observed; the d.r. ranged from 1 : 1.1 to 1 : 1.5 only when chiral ester and amide protecting groups were used. In the final chapter, the α-alkylation

  2. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3830 Formaldehyde, reaction... new uses subject to reporting. (1) The chemical substance identified generically as Formaldehyde...

  3. Alkylation of hydrothiophosphoryl compounds in conditions of interphase catalysis

    International Nuclear Information System (INIS)

    Aladzheva, I.M.; Odinets, I.L.; Petrovskij, P.V.; Mastryukova, T.A.; Kabachkin, M.I.

    1993-01-01

    A method of interphase catalysis permitted to develop a common method for synthesis of compounds with thiophosphoryl group. The effect of nature of hydrothiophosphoryl compound, alkylating agent, two-phase system and reaction conditions on alkylation product yields was investigated in detail

  4. Alcohols as alkylating agents in heteroarene C-H functionalization

    Science.gov (United States)

    Jin, Jian; MacMillan, David W. C.

    2015-09-01

    Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of `spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.

  5. Alcohols as alkylating agents in heteroarene C–H functionalization

    Science.gov (United States)

    Jin, Jian; MacMillan, David W. C.

    2015-01-01

    Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage1. One of the core principles that underlies DNA biosynthesis is the radical-mediated elimnation of H2O to deoxygenate ribonucleotides, an example of ‘spin-center shift’ (SCS)2, during which an alcohol C–O bond is cleaved, resulting in a carbon-centered radical intermediate. While SCS is a well-understood biochemical process, it is underutilized by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylations using alcohols as radical precursors. Considering traditional radical-based alkylation methods require the use of stoichiometric oxidants, elevated temperatures, or peroxides3–7, the development of a mild protocol using simple and abundant alkylating agents would have significant utility in the synthesis of diversely functionalized pharmacophores. In this manuscript, we describe the successful execution of this idea via the development of a dual catalytic alkylation of heteroarenes using alcohols as mild alkylating reagents. This method represents the first broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer (HAT) catalysis. The utility of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone. PMID:26308895

  6. Nitrate denitrification with nitrite or nitrous oxide as intermediate products: Stoichiometry, kinetics and dynamics of stable isotope signatures.

    Science.gov (United States)

    Vavilin, V A; Rytov, S V

    2015-09-01

    A kinetic analysis of nitrate denitrification by a single or two species of denitrifying bacteria with glucose or ethanol as a carbon source and nitrite or nitrous oxide as intermediate products was performed using experimental data published earlier (Menyailo and Hungate, 2006; Vidal-Gavilan et al., 2013). Modified Monod kinetics was used in the dynamic biological model. The special equations were added to the common dynamic biological model to describe how isotopic fractionation between N species changes. In contrast to the generally assumed first-order kinetics, in this paper, the traditional Rayleigh equation describing stable nitrogen and oxygen isotope fractionation in nitrate was derived from the dynamic isotopic equations for any type of kinetics. In accordance with the model, in Vidal-Gavilan's experiments, the maximum specific rate of nitrate reduction was proved to be less for ethanol compared to glucose. Conversely, the maximum specific rate of nitrite reduction was proved to be much less for glucose compared to ethanol. Thus, the intermediate nitrite concentration was negligible for the ethanol experiment, while it was significant for the glucose experiment. In Menyailo's and Hungate's experiments, the low value of maximum specific rate of nitrous oxide reduction gives high intermediate value of nitrous oxide concentration. The model showed that the dynamics of nitrogen and oxygen isotope signatures are responding to the biological dynamics. Two microbial species instead of single denitrifying bacteria are proved to be more adequate to describe the total process of nitrate denitrification to dinitrogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Identify alkylation hazards

    International Nuclear Information System (INIS)

    Scott, B.

    1992-01-01

    This paper reports that extensive experience shows that alkylation plants regardless of acid catalyst choice, can be operated safely, and with minimum process risk to employees or neighbors. Both types of plants require a comprehensive and fully supported hazard management program that accounts for differing physical properties of the acids involved. Control and mitigation cost to refiners will vary considerably from plant to plant and location to location. In the author's experience, the order of magnitude costs will be about $1 to $2 million for a sulfuric acid (SA) alkylation plant, and about $10 to $15 million for a hydrofluoric acid (HF) plant. These costs include water supply systems and impoundment facilities for contaminated runoff water. The alkylation process, which chemically reacts isobutane and light olefins in the presence of a strong acid catalyst into a premium gasoline component is described

  8. Preparation of trialkylindium by alkylation of metallic indium

    International Nuclear Information System (INIS)

    Eremeev, I.V.; Danov, S.M.; Sakhipov, V.R.

    1995-01-01

    The investigation results on production of trialkyl indium by alkylation of metallic indium are presented. In contradistinction to the known techniques for the production of trialkyls on indium by alkylation it is suggested to separate the synthesis into two steps. At the first step indium is alkylated by alkylhalide to alkyl indium halide, and at the second alkylation is carried out using. Grignard reagent. The techniques for preparation of trimethyl- and triethylindium, developed on the bases of this scheme, are noted for good reproducibility, allow to preclude, agglomeration of indium during the synthesis, as well as to reduce the consumption coefficients, and amounts, of the introduced starting reagents, i.e. magnesium and alkylhalide. Refs. 16

  9. Latitudinal variations in intermediate depth ventilation and biological production over northeastern Pacific Oxygen Minimum Zones during the last 60 ka

    Science.gov (United States)

    Cartapanis, Olivier; Tachikawa, Kazuyo; Bard, Edouard

    2012-10-01

    Mechanisms affecting past variability in the Oxygen Minimum Zone (OMZ) in the Eastern Tropical North Pacific (ETNP) are poorly known. We analyzed core MD02-2524, obtained from the Nicaragua Margin in the present ETNP OMZ for major and minor elements (titanium (Ti), brome (Br), silicon (Si), potassium (K), and calcium (Ca)) using an X-ray Fluorescence (XRF) core scanner, and redox-sensitive trace elements (uranium (U), molybdenum (Mo), and nickel (Ni)) determined by ICP-MS. The U and Mo content was higher during the deglaciation than during the Holocene and the last glacial maximum, whereas enrichment was not observed for Ni, an element closely associated with organic matter. High-resolution XRF scanning indicated that the Ca-based carbonate content had millennial-scale variability inversely correlated with Br-based organic matter and Si/K-based opal content during the last glacial period. The available data suggest no clear regional trend in biological productivity during the last deglaciation, but significant local variability in the coastal eastern equatorial Pacific. The trace element enrichment and the lack of a concomitant increase in biogenic phases indicated that an enhanced ETNP OMZ, at least between 15°N and 12°N at a water depth of 500-900 m, was principally caused by a reduced oxygen supply driven by oceanic circulation to the Nicaragua Basin during the deglaciation. The observed patterns can be interpreted as the distinct changes in the oxygenation state of northern and southern water masses at intermediate depths. We also found evidence for a decoupling between local productivity and pore water oxygenation for several millennial-scale events during Marine Isotopic Stage 3, indicating that remote oxygen consumption and/or oceanic ventilation impacted OMZ intensity. Multi-millennial scale variations of the productivity at Papagayo upwelling cell displayed an opposite trend from productivity at the Costa Rica Dome, in relation with the latitudinal shift

  10. Palladium catalysed asymmetric alkylation of benzophenone Schiff ...

    Indian Academy of Sciences (India)

    Asymmetric alkyl substitution of various benzophenone Schiff base substrates under biphasic conditions proceeded using optically active Palladium(II) complexes. The corresponding products were obtained in high yields but with moderate enantiomeric excess (ee). Addition of specific ionic liquids to the reaction medium ...

  11. Laboratory-scale production of adu gels by external gelation for an intermediate HTGR nuclear

    International Nuclear Information System (INIS)

    S Simbolon; SR Susilowati

    2015-01-01

    The The aim of this research is to produce thousands of microsphere ADU (Ammonium Diuranate) gels by using external gelation for an intermediate HTGR (High Temperature Gas-cooled Reactor) nuclear fuel in laboratory-scale. Microsphere ADU gels were based on sol-solution which was made from a homogeneous mixture of ADUN (Acid Deficient Uranyl Nitrate) which was containing uranyl ion in high concentration, a water soluble organic compound PVA (Polyvinyl Alcohol) and THFA (Tetrahydrofurfuryl Alcohol). The simple unified home made laboratory experimental machine was developed to replace test tube experiment method which was once used due to a tiny amount of microsphere ADU gels produced. It consists of four main parts: tank filled sol-solution connecting to peristaltic pump and vibrating nozzle, preliminary gelation and gelation column. The machine has successfully converted 150 mL sol-solution into thousands of drops which produced 120 - 130 drops in each minute in steady state in ammonia gas free sector. Preliminary gelation reaction was carried out in ammonia gas sector where drops react with ammonia gas in a bat an eye followed by gelation reaction in column containing ammonia solution 7 M. In ageing process, ADU gels were collected and submerged into a vessel containing ammonia solution which was shaken for 1 hour in a shaker device. Isopropyl alcohol (90 %) solution was used to wash ADU gels and a digital camera was used to measured spherical form of ADU gels. Diameters in spherical spheroid form were found between 1.8 mm until 2.2 mm. The spherical purity of ADU gels were 10 % - 20 % others were oblate, prolate spheroid and microsphere which have hugetiny of dimples on the surface. (author)

  12. Theoretical and experimental studies of the neutron rich fission product yields at intermediate energies

    Directory of Open Access Journals (Sweden)

    Äystö J.

    2012-02-01

    Full Text Available A new method to measure the fission product independent yields employing the ion guide technique and a Penning trap as a precision mass filter, which allows an unambiguous identification of the nuclides is presented. The method was used to determine the independent yields in the proton-induced fission of 232Th and 238U at 25 MeV. The data were analyzed with the consistent model for description of the fission product formation cross section at the projectile energies up to 100 MeV. Pre-compound nucleon emission is described with the two-component exciton model using Monte Carlo method. Decay of excited compound nuclei is treated within time-dependent statistical model with inclusion of the nuclear friction effect. The charge distribution of the primary fragment isobaric chain was considered as a result of frozen quantal fluctuations of the isovector nuclear density. The theoretical predictions of the independent fission product cross sections are used for normalization of the measured fission product isotopic distributions.

  13. The Effect of Meaning-Focused Listening Input on Iranian Intermediate EFL Learners' Productive Vocabulary Size

    Science.gov (United States)

    Noughabi, Mostafa Azari

    2017-01-01

    Vocabulary as a significant component of language learning has been widely researched. As well, it is well documented that vocabulary could be learned through listening and reading. In addition, measuring productive vocabulary has been a chief concern among scholars. However, few studies have focused on meaning-focused listening input and its…

  14. A product designed for final disposal of low and intermediate level radioactive wastes

    International Nuclear Information System (INIS)

    Baboescu, E.; Popescu, I. V.

    2001-01-01

    The product 'metallic barrel - concrete - low level radioactive wastes - 1' (ABBD - 1) was certified according to the company's standard SF ICN/1994, updated 1. The product ABBD -1 is produced according to the following certified technologies: - technology for processing and conditioning of low level radioactive solid wastes; - technology for processing and conditioning of waste ion exchangers from the TRIGA reactor; - technology for conditioning the β - γ radioactive compacts. The product is constituted of a protection shield, the concrete block - radioactive waste, securing high mechanical strength and a high degree of radionuclides retaining, thus ensuring the necessary condition for long time disposal and, finally, the metallic container fulfilling the National Standards of Nuclear Safety for Radioactive Materials Transportation. The metallic container is made of pickled slab, with a 220 l capacity, according to STAS 7683/88 standards. The main characteristics of the product 'ABBD - 1' are: - size: height, 915 ± 10 mm, diameter, 600 ± 5 mm; - mass, 300 - 600 kg; - maximum permissible activity, 6 x 10 9 Bq/ barrel (0.164 Ci/barrel); - equivalent dose rate for gamma radiation at barrel's wall, max. 1 mSv/h (200 mrem/h); - unfixed external contamination, 2 ; - compression strength of concrete block alone, > 5 x 10 6 N/m 2 ; - lixiviation rate, -3 cm/day; - the compact concrete block-radioactive waste is leak-proof and crack-free. The final product is transferred from INR Pitesti to National Repository for Radioactive Waste by railway and road transportation according to the provisions of the National Commission for Nuclear Activity Control as stipulated in the National Standards of Nuclear Safety of Radioactive Materials Transportation

  15. Synthesis and DNA cleavage activity of Bis-3-chloropiperidines as alkylating agents.

    Science.gov (United States)

    Zuravka, Ivonne; Roesmann, Rolf; Sosic, Alice; Wende, Wolfgang; Pingoud, Alfred; Gatto, Barbara; Göttlich, Richard

    2014-09-01

    Nitrogen mustards are an important class of bifunctional alkylating agents routinely used in chemotherapy. They react with DNA as electrophiles through the formation of highly reactive aziridinium ion intermediates. The antibiotic 593A, with potential antitumor activity, can be considered a naturally occurring piperidine mustard containing a unique 3-chloropiperidine ring. However, the total synthesis of this antibiotic proved to be rather challenging. With the aim of designing simplified analogues of this natural product, we developed an efficient bidirectional synthetic route to bis-3-chloropiperidines joined by flexible, conformationally restricted, or rigid diamine linkers. The key step involves an iodide-catalyzed double cyclization of unsaturated bis-N-chloroamines to simultaneously generate both piperidine rings. Herein we describe the synthesis and subsequent evaluation of a series of novel nitrogen-bridged bis-3-chloropiperidines, enabling the study of the impact of the linker structure on DNA alkylation properties. Our studies reveal that the synthesized compounds possess DNA alkylating abilities and induce strand cleavage, with a strong preference for guanine residues. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Sulfonyl and phosphoryl azides: going further beyond the click realm of alkyl and aryl azides.

    Science.gov (United States)

    Kim, Seok Hwan; Park, Sae Hume; Choi, Ji Ho; Chang, Sukbok

    2011-10-04

    Whereas alkyl and aryl azides readily react with terminal alkynes to afford 1,4-disubstituted-1,2,3-triazoles in excellent yields and selectivity in the presence of a copper catalyst, sulfonyl, phosphoryl, and certain acyl azides allow additional chemistry upon ring-opening of the corresponding copper-triazole intermediates. The amazingly versatile new chemistry stems from the high reactivity of a ring-opened ketenimine intermediate, with which a wide range of nucleophiles react to give multicomponent products. Among those nucleophiles, amines, alcohols, water, and heterocyclic compounds are especially capable of being involved in this new chemistry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Catalytic alkylation of remote C-H bonds enabled by proton-coupled electron transfer.

    Science.gov (United States)

    Choi, Gilbert J; Zhu, Qilei; Miller, David C; Gu, Carol J; Knowles, Robert R

    2016-11-10

    Despite advances in hydrogen atom transfer (HAT) catalysis, there are currently no molecular HAT catalysts that are capable of homolysing the strong nitrogen-hydrogen (N-H) bonds of N-alkyl amides. The motivation to develop amide homolysis protocols stems from the utility of the resultant amidyl radicals, which are involved in various synthetically useful transformations, including olefin amination and directed carbon-hydrogen (C-H) bond functionalization. In the latter process-a subset of the classical Hofmann-Löffler-Freytag reaction-amidyl radicals remove hydrogen atoms from unactivated aliphatic C-H bonds. Although powerful, these transformations typically require oxidative N-prefunctionalization of the amide starting materials to achieve efficient amidyl generation. Moreover, because these N-activating groups are often incorporated into the final products, these methods are generally not amenable to the direct construction of carbon-carbon (C-C) bonds. Here we report an approach that overcomes these limitations by homolysing the N-H bonds of N-alkyl amides via proton-coupled electron transfer. In this protocol, an excited-state iridium photocatalyst and a weak phosphate base cooperatively serve to remove both a proton and an electron from an amide substrate in a concerted elementary step. The resultant amidyl radical intermediates are shown to promote subsequent C-H abstraction and radical alkylation steps. This C-H alkylation represents a catalytic variant of the Hofmann-Löffler-Freytag reaction, using simple, unfunctionalized amides to direct the formation of new C-C bonds. Given the prevalence of amides in pharmaceuticals and natural products, we anticipate that this method will simplify the synthesis and structural elaboration of amine-containing targets. Moreover, this study demonstrates that concerted proton-coupled electron transfer can enable homolytic activation of common organic functional groups that are energetically inaccessible using

  18. Bioethanol Production from Raw Juice as Intermediate of Sugar Beet Processing: A Response Surface Methodology Approach

    Directory of Open Access Journals (Sweden)

    Stevan Popov

    2010-01-01

    Full Text Available Response surface methodology (RSM was used for selecting optimal fermentation time and initial sugar mass fraction in cultivation media based on raw juice from sugar beet in order to produce ethanol. Optimal fermentation time and initial sugar mass fraction for ethanol production in batch fermentation by free Saccharomyces cerevisiae cells under anaerobic conditions at the temperature of 30 °C and agitation rate of 200 rpm were estimated to be 38 h and 12.30 % by mass, respectively. For selecting optimal conditions for industrial application, further techno-economic analysis should be performed by using the obtained mathematical representation of the process (second degree polynomial model. The overall fermentation productivity of five different types of yeast was examined and there is no significant statistical difference between them.

  19. Role of glycolytic intermediate in regulation: Improving lycopene production in Escherichia coli by engineering metabolic control

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, W.R.; Liao, J.C.

    2001-06-01

    Metabolic engineering in the postgenomic era is expected to benefit from a full understanding of the biosynthetic capability of microorganisms as a result of the progress being made in bioinformatics and functional genomics. The immediate advantage of such information is to allow the rational design of novel pathways and the elimination of native reactions that are detrimental or unnecessary for the desired purpose. However, with the ability to manipulate metabolic pathways becoming more effective, metabolic engineering will need to face a new challenge: the reengineering of the regulatory hierarchy that controls gene expression in those pathways. In addition to constructing the genetic composition of a metabolic pathway, they propose that it will become just as important to consider the dynamics of pathways gene expression. It has been widely observed that high-level induction of a recombinant protein or pathway leads to growth retardation and reduced metabolic activity. These phenotypic characteristics result from the fact that the constant demands of production placed upon the cell interfere with its changing requirements for growth. They believe that this common situation in metabolic engineering can be alleviated by designing a dynamic controller that is able to sense the metabolic state of the cell and regulate the expression of the recombinant pathway accordingly. This approach, which is termed metabolic control engineering, involves redesigning the native regulatory circuits and applying them to the recombinant pathway. The general goal of such an effort will be to control the flux to the recombinant pathway adaptively according to the cell's metabolic state. The dynamically controlled recombinant pathway can potentially lead to enhanced production, minimized growth retardation, and reduced toxic by-product formation. The regulation of gene expression in response to the physiological state is also essential to the success of gene therapy. Here they

  20. Vector mesons in dense matter and dilepton production in heavy ion collisions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Santini, Elvira

    2008-02-15

    The vector meson spectral functions are calculated to the first order in the nuclear matter density assuming the dominant contribution comes from the couplings of the vector mesons to nucleons and nucleon resonances. An attempt is made to reproduce the HADES dilepton production data with the in-medium spectral functions of the vector mesons using the Relativistic Quantum Molecular Dynamics (RQMD) transport model developed earlier for modelling heavy-ion collisions. The results are sensitive to the in-medium broadening of nucleon resonances. A generally good agreement with the HADES data is achieved for selfconsistent treatment of the nucleon resonance broadening and the vector meson spectral functions. (orig.)

  1. Development of safe and shelf-stable Intermediate Moisture (IM) convenience meat products through radiation processing

    International Nuclear Information System (INIS)

    Ramesh Chander; Kanatt, S.R.; Chawla, S.P.; Bongirwar, D.R.

    2001-01-01

    Ready-to-use shelf stable mutton and chicken sheek kababs, and chicken chilly were developed by reducing the water activity either by grilling or by hot air drying, vacuum packing and irradiation. Microbiological analysis revealed a dose dependent reduction in total viable count and in Staphylococcus species on irradiation treatment ( 2.5, 5.0 and 10.0 kGy). The products subjected to irradiation at 10 kGy showed absence of viable micro-organisms and also had high sensory acceptability up to 9 months at ambient temperature. (author)

  2. Measurement-model comparison of stabilized Criegee intermediate and highly oxygenated molecule production in the CLOUD chamber

    Science.gov (United States)

    Sarnela, Nina; Jokinen, Tuija; Duplissy, Jonathan; Yan, Chao; Nieminen, Tuomo; Ehn, Mikael; Schobesberger, Siegfried; Heinritzi, Martin; Ehrhart, Sebastian; Lehtipalo, Katrianne; Tröstl, Jasmin; Simon, Mario; Kürten, Andreas; Leiminger, Markus; Lawler, Michael J.; Rissanen, Matti P.; Bianchi, Federico; Praplan, Arnaud P.; Hakala, Jani; Amorim, Antonio; Gonin, Marc; Hansel, Armin; Kirkby, Jasper; Dommen, Josef; Curtius, Joachim; Smith, James N.; Petäjä, Tuukka; Worsnop, Douglas R.; Kulmala, Markku; Donahue, Neil M.; Sipilä, Mikko

    2018-02-01

    Atmospheric oxidation is an important phenomenon which produces large quantities of low-volatility compounds such as sulfuric acid and oxidized organic compounds. Such species may be involved in the nucleation of particles and enhance their subsequent growth to reach the size of cloud condensation nuclei (CCN). In this study, we investigate α-pinene, the most abundant monoterpene globally, and its oxidation products formed through ozonolysis in the Cosmic Leaving OUtdoor Droplets (CLOUD) chamber at CERN (the European Organization for Nuclear Research). By scavenging hydroxyl radicals (OH) with hydrogen (H2), we were able to investigate the formation of highly oxygenated molecules (HOMs) purely driven by ozonolysis and study the oxidation of sulfur dioxide (SO2) driven by stabilized Criegee intermediates (sCIs). We measured the concentrations of HOM and sulfuric acid with a chemical ionization atmospheric-pressure interface time-of-flight (CI-APi-TOF) mass spectrometer and compared the measured concentrations with simulated concentrations calculated with a kinetic model. We found molar yields in the range of 3.5-6.5 % for HOM formation and 22-32 % for the formation of stabilized Criegee intermediates by fitting our model to the measured sulfuric acid concentrations. The simulated time evolution of the ozonolysis products was in good agreement with measured concentrations except that in some of the experiments sulfuric acid formation was faster than simulated. In those experiments the simulated and measured concentrations met when the concentration reached a plateau but the plateau was reached 20-50 min later in the simulations. The results shown here are consistent with the recently published yields for HOM formation from different laboratory experiments. Together with the sCI yields, these results help us to understand atmospheric oxidation processes better and make the reaction parameters more comprehensive for broader use.

  3. Bio-oil production of softwood and hardwood forest industry residues through fast and intermediate pyrolysis and its chromatographic characterization.

    Science.gov (United States)

    Torri, Isadora Dalla Vecchia; Paasikallio, Ville; Faccini, Candice Schmitt; Huff, Rafael; Caramão, Elina Bastos; Sacon, Vera; Oasmaa, Anja; Zini, Claudia Alcaraz

    2016-01-01

    Bio-oils were produced through intermediate (IP) and fast pyrolysis (FP), using Eucalyptus sp. (hardwood) and Picea abies (softwood), wood wastes produced in large scale in Pulp and Paper industries. Characterization of these bio-oils was made using GC/qMS and GC×GC/TOFMS. The use of GC×GC provided a broader characterization of bio-oils and it allowed tracing potential markers of hardwood bio-oil, such as dimethoxy-phenols, which might co-elute in 1D-GC. Catalytic FP increased the percentage of aromatic hydrocarbons in P. abies bio-oil, indicating its potential for fuel production. However, the presence of polyaromatic hydrocarbons (PAH) draws attention to the need of a proper management of pyrolysis process in order to avoid the production of toxic compounds and also to the importance of GC×GC/TOFMS use to avoid co-elutions and consequent inaccuracies related to identification and quantification associated with GC/qMS. Ketones and phenols were the major bio-oil compounds and they might be applied to polymer production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Biological Production of a Hydrocarbon Fuel Intermediate Polyhydroxybutyrate (PHB) from a Process Relevant Lignocellulosic Derived Sugar (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Mittal, A.; Mohagheghi, A.; Johnson, D. K.

    2014-04-01

    PHAs are synthesized by many microorganisms to serve as intracellular carbon storage molecules. In some bacterial strains, PHB can account for up to 80% of cell mass. In addition to its application in the packaging sector, PHB also has great potential as an intermediate in the production of hydrocarbon fuels. PHB can be thermally depolymerized and decarboxylated to propene which can be upgraded to hydrocarbon fuels via commercial oligomerization technologies. Cupriavidus necator is the microorganism that has been most extensively studied and used for PHB production on an industrial scale; However the substrates used for producing PHB are mainly fructose, glucose, sucrose, fatty acids, glycerol, etc., which are expensive. In this study, we demonstrate production of PHB from a process relevant lignocellulosic derived sugar stream, i.e., saccharified slurry from pretreated corn stover. The strain was first investigated in shake flasks for its ability to utilize glucose, xylose and acetate. In addition, the strain was also grown on pretreated lignocellulose hydrolyzate slurry and evaluated in terms of cell growth, sugar utilization, PHB accumulation, etc. The mechanism of inhibition in the toxic hydrolysate generated by the pretreatment and saccharification process of biomass, was also studied.

  5. Production and decay of charged intermediate vector bosons in p anti p collisions

    International Nuclear Information System (INIS)

    Guchte, M.W. van de.

    1991-01-01

    This thesis describes an experiment performed with the UA1 detector at the Spp-barS at CERN on the production and decay of W ± bosons in proton-antiproton collisions. In particular the total width of the W ± resonance has been determined. A direct measurement of this quantity already exists, but with an uncertainty of 70%. Here an indirect method is presented in which this quantity is inferred from the ratio of the W →lv and Z → ll-bar partial cross sections measured at pp-bar colliders and the total width of the Z boson, accurately measured at LEP. It exploits the complementary results of pp-bar and e + e - machines and allows to bring down the uncertainty on the total width to about 8%. The results is compared with the Standard Model prediction and its implication for the mass of the top quark is investigated. Also the possibility to put a constraint on the masses of the new elementary particles predicted by the Super Symmetry model is considered. (author). 126 refs.; 67 figs.; 23 tabs

  6. Sketches from a design process: creative cognition inferred from intermediate products.

    Science.gov (United States)

    Jaarsveld, Saskia; Leeuwen, Cees

    2005-01-02

    Novice designers produced a sequence of sketches while inventing a logo for a novel brand of soft drink. The sketches were scored for the presence of specific objects, their local features and global composition. Self-assessment scores for each sketch and art critics' scores for the end products were collected. It was investigated whether the design evolves in an essentially random fashion or according to an overall heuristic. The results indicated a macrostructure in the evolution of the design, characterized by two stages. For the majority of participants, the first stage is marked by the introduction and modification of novel objects and their local and global aspects; the second stage is characterized by changes in their global composition. The minority that showed the better designs has a different strategy, in which most global changes were made in the beginning. Although participants did not consciously apply these strategies, their self-assessment scores reflect the stages of the process. 2005 Lawrence Erlbaum Associates, Inc.

  7. Method of making alkyl esters

    Science.gov (United States)

    Elliott, Brian

    2010-09-14

    Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

  8. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

  9. Distribution of methyl and ethyl adducts following alkylation with monofunctional alkylating agents.

    Science.gov (United States)

    Beranek, D T

    1990-07-01

    Alkylating agents, because of their ability to react directly with DNA either in vitro or in vivo, or following metabolic activation as in the case of the dialkylnitrosamines, have been used extensively in studying the mechanisms of mutagenicity and carcinogenicity. Their occurrence is widespread in the environment and human exposure from natural and pollutant sources is universal. Since most of these chemicals show varying degrees of both carcinogenicity and mutagenicity, and exhibit compound-specific binding patterns, they provide an excellent model for studying molecular dosimetry. Molecular dosimetry defines dose as the number of adducts bound per macromolecule and relates the binding of these adducts to the human mutagenic or carcinogenic response. This review complies DNA alkylation data for both methylating and ethylating agents in a variety of systems and discusses the role these alkylation products plays in molecular mutagenesis.

  10. Decentralized scheduling algorithm to improve the rate of production without increasing the stocks of intermediates; Zaiko wo fuyasu kotonaku seisan sokudo wo kojo saseru jiritsu bunsangata sukejuringu arugorizumu

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Kazuhiro; Shiigi, Daisuke; Tsuge, Yoshifumi; Matsuyama, Hisayoshi [Kyushu University, Fukuoka (Japan). Department of Chemical Engineering

    1999-03-10

    In a factory with a multi-stage production system, push-type scheduling methods can hardly improve the production rate without increasing the stocks of intermediates. For products whose specifications are known before their orders, a pull-type scheduling method named Kanban system has been developed, and has succeeded to improve the production rate without increasing the stocks of intermediates. The Kanban system, however, is not applicable to custom-made products whose specifications are not known before their orders. In this paper, a 'Virtual Kanban (VK) system' is presented as a pull-type scheduling method which is applicable to custom-made products, and its usefulness is demonstrated by simulation of an application specific integrated circuit manufacturing facility. (author)

  11. Intermediate Product Regulation in Tandem Solid Catalysts with Multimodal Porosity for High-Yield Synthetic Fuel Production.

    Science.gov (United States)

    Duyckaerts, Nicolas; Bartsch, Mathias; Trotuş, Ioan-Teodor; Pfänder, Norbert; Lorke, Axel; Schüth, Ferdi; Prieto, Gonzalo

    2017-09-11

    Tandem catalysis is an attractive strategy to intensify chemical technologies. However, simultaneous control over the individual and concerted catalyst performances poses a challenge. We demonstrate that enhanced pore transport within a Co/Al 2 O 3 Fischer-Tropsch (FT) catalyst with hierarchical porosity enables its tandem integration with a Pt/ZSM-5 zeolitic hydrotreating catalyst in a spatially distant fashion that allows for catalyst-specific temperature adjustment. Nevertheless, this system resembles the case of close active-site proximity by mitigating secondary reactions of primary FT α-olefin products. This approach enables the combination of in situ dewaxing with a minimum production of gaseous hydrocarbons (18 wt %) and an up to twofold higher (50 wt %) selectivity to middle distillates compared to tandem pairs based on benchmark mesoporous FT catalysts. An overall 80 % selectivity to liquid hydrocarbons from syngas is attained in one step, attesting to the potential of this strategy for increasing the carbon efficiency in intensified gas-to-liquid technologies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Nicotinamide-NAD sequence: redox process and related behavior, behavior and properties of intermediate and final products

    International Nuclear Information System (INIS)

    Elving, P.J.; Schmakel, C.O.; Santhanam, K.S.V.

    1976-01-01

    Illustrations of the application of analytical chemical techniques to the study of chemical phenomena are given. In particular, electrochemical techniques and methodology and, to a lesser extent, spectrophotometry were used to investigate the solution behavior, adsorption, redox processes including coupled chemical reactions, and allied aspects of biologically significant compounds and of their intermediate and final redox products, e.g., the behavior of the free radicals produced by initial one-electron processes. This approach is illustrated by the consideration of the behavior in aqueous and nonaqueous media of a sequence of compounds ranging from nicotinamide (3-carbamoylpyridine) to NAD + and NADP + ; the latter compounds function as coenzymes for the pyridinoproteins which are principal components in the Krebs citric acid cycle and in the electron transport chain in biological redox reactions. The discussion is presented under the following section headings: interpretation of electrochemical behavior; mechanistic patterns; kinetic aspects of charge-transfer and chemical reactions; correlation with theoretically calculated parameters; and, mechanisms of biological oxidation-reduction reactions. The use of pulse radiolysis, chronopotentiometric, and cyclic voltammetric methods in studies on free radical dimerization rates is reviewed in the discussion of the kinetic aspects of charge-transfer and chemical reactions. (188 references)

  13. Intermediate pyrolysis of agro-industrial biomasses in bench-scale pyrolyser: Product yields and its characterization.

    Science.gov (United States)

    Tinwala, Farha; Mohanty, Pravakar; Parmar, Snehal; Patel, Anant; Pant, Kamal K

    2015-01-01

    Pyrolysis of woody biomass, agro-residues and seed was carried out at 500 ± 10 °C in a fixed bed pyrolyser. Bio-oil yield was found varying from 20.5% to 47.5%, whereas the biochar and pyrolysis gas ranged from 27.5% to 40% and 24.5% to 40.5%, respectively. Pyrolysis gas was measured for flame temperature along with CO, CO2, H2, CH4 and other gases composition. HHV of biochar (29.4 MJ/kg) and pyrolitic gas (8.6 MJ/kg) of woody biomass was higher analogous to sub-bituminous coal and steam gasification based producer gas respectively, whereas HHV of bio-oil obtained from seed (25.6 MJ/kg) was significantly more than husks, shells and straws. TGA-DTG studies showed the husks as potential source for the pyrolysis. Bio-oils as a major by-product of intermediate pyrolysis have several applications like substitute of furnace oil, extraction of fine chemicals, whereas biochar as a soil amendment for enhancing soil fertility and gases for thermal application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Reaction engineering of urea alcoholysis: Alkyl carbamates

    OpenAIRE

    Mote, Dhananjay R.; Ranade, Vivek V.

    2017-01-01

    Urea alcoholysis is a reversible reaction generating alkyl carbamate and ammonia as products. The reaction can be performed non-catalytically or in presence of catalyst. The first step in Reaction engineering analysis is to finalize the reactor configuration. In this case it is important to determine the necessity of reactive separation (simultaneous reaction and separation). This has been addressed by first establishing the reversibility of the reaction through theoretical and experimental i...

  15. Co-metabolic enhancement of organic removal from waste water in the presence of high levels of alkyl paraben constituents of cosmetic and personal care products.

    Science.gov (United States)

    Fan, Chihhao; Wang, Shin-Chih

    2017-07-01

    The enhanced removal of organic material from municipal waste water containing 50 mg/L of chemical oxygen demand and a given amount of alkyl paraben using a biofilm system was investigated. The parabens used were methyl, ethyl, and propyl paraben. The experiments were conducted at influent paraben concentrations of 10 and 50 mg/L. The influent pH was measured around 4.6 because of paraben hydrolysis. The effluent pH increased due to hydrogen consumption and small molecular acid generation. The higher removal rates were observed for the paraben with longer alkyl chains, which were more hydrophobic and capable of penetrating into microbial cells. The co-existing organic constituents in municipal waste water were found to be competitive with paraben molecules for microbial degradation at low paraben loading (i.e., 10 mg/L). Instead, the co-metabolic effect was observed at a higher paraben loading (i.e., 50 mg/L) due to more active enzymatic catalysis, implying the possible enhancement or organic removal in the presence of high levels of parabens. The difference in BOD and TOC removing ratios for parabens decreased with increasing HRT, implying their better mineralization than that of municipal organic constituents. This was because the microbial organism became more adapted to the reacting system with longer HRT, and more oxygenase was produced to facilitate the catechol formation and ring-opening reactions, causing apparent enhancement in mineralization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Alkyl-Substituted δ-Lactones Derived from Dihydrojasmone and Their Stereoselective Fungi-Mediated Conversion: Production of New Antifeedant Agents

    Directory of Open Access Journals (Sweden)

    Anna Gliszczyńska

    2016-09-01

    Full Text Available A chemoenzymatic method was applied to obtain optically pure alkyl-substituted δ-lactones. First, chemical Baeyer–Villiger oxidation of dihydrojasmone (1 was carried out, affording two new alkyl-substituted δ-lactones: 3,4-dihydro-5-methyl-6-pentyl-2H-pyran-2-one (2 and 5-methyl-6-pentyl-1,13-dioxabicyclo[4.1.0]heptan-2-one (3. In the next step, fungal strains were investigated as biocatalysts to enantioselective conversion of δ-lactones (2 and (3. The fungal cultures: Fusarium culmorum AM10, Fusarium equiseti AM15 and Beauveria bassiana AM278 catalyzed the stereoselective hydration of the double bond of lactone (2 (ee = 20%–99% while Didymosphaeria igniaria KCh6670 proved to be the best biocatalyst for the reduction of carbonyl group in the epoxylactone (3 (ee = 99%. In both cases, chiral oxyderivatives were obtained in low to high yields (7%–91%. The synthetic lactones (2, (3 and its derivatives (4, (5 were tested for their antifeedant activity towards larvae and adults of lesser mealworm (Alphitobius diaperinus Panzer and peach potato aphid (Myzus persicae [Sulzer] and some of them were active towards studied insects.

  17. Production and muonic decay of the Z/sup 0/ intermediate vector boson in the UA1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Leuchs, Reinhard

    1988-02-17

    In the years 1982 to 1985 the intermediate bosons W/sup + -/ and Z/sup 0/ were detected in all the leptonic decay channels. In the present work we examined experimentally the production of the Z/sup 0/ in proton-antiproton collisions, followed by decay of the Z/sup 0/ into two muons. At present this is possible only in the UA1 experiment. Within the framework of this work I was initially responsible for the correct data readout from the muon detector. For this purpose it was necessary to build a monitoring system based on microprocessors, which could be used to monitor and test our apparatus. This monitoring system contains numerous programs for the diagnosis of the equipment. In the analysis I first selected the Z/sup 0/ events in the runs of 1984 and 1985, and then determined the efficiency of this selection. I also participated in setting up the p/sub t//sup ..mu../ > 15 GeV/c selection. Then the Z/sup 0/ sample was tested for completeness, and the background calculated anew. The methods of energy balance and mass fitting were refined and systematized. Thus the production properties and the mass of the Z/sup 0/ could be determined for the first time for the entire measurement period of the UA1. The determination of the parameters of the standard model was done by also including the results of analyses from other decay channels of the W and Z bosons. 149 refs., 60 figs., 14 tabs.

  18. The Effects of Guided Careful Online Planning on Complexity, Accuracy and Fluency in Intermediate EFL Learners' Oral Production: The Case of English Articles

    Science.gov (United States)

    Ahmadian, Mohammad Javad

    2012-01-01

    The purpose of the study reported in this article was twofold: First, to see whether guided careful online planning assists intermediate learners of English as a foreign language (EFL) in accurate oral production of English articles ("an/a" and "the"); and, second, to see whether guided careful online planning has any effects…

  19. A two staged condensation of vapors of an isobutane tower in installations for sulfuric acid alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, N.P.; Feyzkhanov, R.I.; Idrisov, A.D.; Navalikhin, P.G.; Sakharov, V.D.

    1983-01-01

    In order to increase the concentration of isobutane to greater than 72 to 76 percent in an installation for sulfuric acid alkylation, a system of two staged condensation of vapors from an isobutane tower is placed into operation. The first stage condenses the heavier part of the upper distillate of the tower, which is achieved through somewhat of an increase in the condensate temperature. The product which is condensed in the first stage is completely returned to the tower as a live irrigation. The vapors of the isobutane fraction which did not condense in the first stage are sent to two newly installed condensers, from which the product after condensation passes through intermediate tanks to further depropanization. The two staged condensation of vapors of the isobutane tower reduces the content of the inert diluents, the propane and n-butane in the upper distillate of the isobutane tower and creates more favorable conditions for the operation of the isobutane and propane tower.

  20. Thermogravimetric studies on alkyl methacrylate polymers and poly(alkyl methacrylate)-grafted polypropylene fibers

    International Nuclear Information System (INIS)

    Hayakawa, Kiyoshi; Taoda, Hiroshi; Kawase, Kaoru; Tazawa, Masato; Yamakita, Hiromi

    1986-01-01

    Thermal behavior of several kinds of poly (alkyl methacrylate) and polypropylene-g-poly (alkyl methacrylate) fibers prepared by γ-irradiation was investigated by thermogravimetric measurements with the intermittent analysis of the gaseous products. The degradation of poly (methyl methacrylate) proceeded according to the deploymerization mechanism reproducing the pristine monomer exclusively. The thermogram in inert atmosphere showed the features of a two-step depolymerization, while in air it showed no such a stepwise decrease with the elevating temperature. The dissolution-precipitation treatment of polymer seemed to affect the decomposition behavior. On other alkyl methacrylate polymers, the thermal decomposition generally proceeded also according to the depolymerization mechanism. But, for instance, at least two kinds of products besides its own monomer were formed from poly (isobutyl methacrylate), and their relative fractions differed with the temperature. Polypropylene-g-poly (alkyl methacrylate) fibers showed lowering of initiation temperature of decomposition with the increase in extent of the grafting, and their initiation temperatures of decomposition in air were lower than those in inert atmosphere. (author)

  1. Liquid phase alkylation of anisole and phenol catalyzed by niobium phosphate

    OpenAIRE

    Pereira, Cynthia C. M.; de la Cruz, Marcus H. C.; Lachter, Elizabeth R.

    2010-01-01

    The catalytic activity of niobium phosphate was evaluated in the liquid phase alkylation reaction of anisole with 1-dodecene, 1- octene, 2-octanol and 1-octen-3-ol and in the reaction of phenol with 1-octen-3-ol. Best results were achieved in the alkylation of anisole and phenol with 1-octen-3-ol that produced mainly monoalkylate products. In the reaction with phenol the major products formed were octenylphenols (C-alkylation) and phenyl-octenyl ether (O-alkylates). The reaction favors the fo...

  2. Aag-initiated base excision repair drives alkylation-induced retinal degeneration in mice.

    Science.gov (United States)

    Meira, Lisiane B; Moroski-Erkul, Catherine A; Green, Stephanie L; Calvo, Jennifer A; Bronson, Roderick T; Shah, Dharini; Samson, Leona D

    2009-01-20

    Vision loss affects >3 million Americans and many more people worldwide. Although predisposing genes have been identified their link to known environmental factors is unclear. In wild-type animals DNA alkylating agents induce photoreceptor apoptosis and severe retinal degeneration. Alkylation-induced retinal degeneration is totally suppressed in the absence of the DNA repair protein alkyladenine DNA glycosylase (Aag) in both differentiating and postmitotic retinas. Moreover, transgenic expression of Aag activity restores the alkylation sensitivity of photoreceptors in Aag null animals. Aag heterozygotes display an intermediate level of retinal degeneration, demonstrating haploinsufficiency and underscoring that Aag expression confers a dominant retinal degeneration phenotype.

  3. Olefin-borane "van der Waals complexes": intermediates in frustrated Lewis pair addition reactions.

    Science.gov (United States)

    Zhao, Xiaoxi; Stephan, Douglas W

    2011-08-17

    The nature of the borane-olefin interactions that take place prior to frustrated Lewis pair addition reactions has been probed employing a Lewis acidic borane tethered to a vinyl group through an alkyl chain. (1)H{(19)F} HOESY spectral data obtained at -50 °C demonstrated the spatial proximity of the boryl and vinyl groups and computational data support the initial formation of a van der Waals borane-olefin complex. Such species serve as intermediates undergoing facile addition reactions with phosphine bases to afford cyclic zwitterionic products.

  4. Hydride Transfer versus Deprotonation Kinetics in the Isobutane–Propene Alkylation Reaction: A Computational Study

    OpenAIRE

    Liu, Chong; van Santen, Rutger A.; Poursaeidesfahani, Ali; Vlugt, Thijs J. H.; Pidko, Evgeny A.; Hensen, Emiel J. M.

    2017-01-01

    The alkylation of isobutane with light alkenes plays an essential role in modern petrochemical processes for the production of high-octane gasoline. In this study we have employed periodic DFT calculations combined with microkinetic simulations to investigate the complex reaction mechanism of isobutane–propene alkylation catalyzed by zeolitic solid acids. Particular emphasis was given to addressing the selectivity of the alkylate formation versus alkene formation, which requires a high rate o...

  5. PARP inhibitors protect against sex- and AAG-dependent alkylation-induced neural degeneration.

    Science.gov (United States)

    Allocca, Mariacarmela; Corrigan, Joshua J; Fake, Kimberly R; Calvo, Jennifer A; Samson, Leona D

    2017-09-15

    Alkylating agents are commonly used to treat cancer. Although base excision repair (BER) is a major pathway for repairing DNA alkylation damage, under certain conditions, the initiation of BER produces toxic repair intermediates that damage healthy tissues. The initiation of BER by the alkyladenine DNA glycosylase (AAG, a.k.a. MPG) can mediate alkylation-induced cytotoxicity in specific cells in the retina and cerebellum of male mice. Cytotoxicity in both wild-type and Aag -transgenic ( AagTg ) mice is abrogated in the absence of Poly(ADP-ribose) polymerase-1 (PARP1). Here, we tested whether PARP inhibitors can also prevent alkylation-induced retinal and cerebellar degeneration in male and female WT and AagTg mice. Importantly, we found that WT mice display sex-dependent alkylation-induced retinal damage (but not cerebellar damage), with WT males being more sensitive than females. Accordingly, estradiol treatment protects males against alkylation-induced retinal degeneration. In AagTg male and female mice, the alkylation-induced tissue damage in both the retina and cerebellum is exacerbated and the sex difference in the retina is abolished. PARP inhibitors, much like Parp1 gene deletion, protect against alkylation-induced AAG-dependent neuronal degeneration in WT and AagTg mice, regardless of the gender, but their efficacy in preventing alkylation-induced neuronal degeneration depends on PARP inhibitor characteristics and doses. The recent surge in the use of PARP inhibitors in combination with cancer chemotherapeutic alkylating agents might represent a powerful tool for obtaining increased therapeutic efficacy while avoiding the collateral effects of alkylating agents in healthy tissues.

  6. Balanced activation of IspG and IspH to eliminate MEP intermediate accumulation and improve isoprenoids production in Escherichia coli.

    Science.gov (United States)

    Li, Qingyan; Fan, Feiyu; Gao, Xiang; Yang, Chen; Bi, Changhao; Tang, Jinlei; Liu, Tao; Zhang, Xueli

    2017-11-01

    The MEP pathway genes were modulated to investigate whether there were new rate-limiting steps and toxic intermediates in this pathway. Activating IspG led to significant decrease of cell growth and β-carotene production. It was found that ispG overexpression led to accumulation of intermediate HMBPP, which seriously interfered with synthesis machinery of nucleotide and protein in Escherichia coli. Activation of the downstream enzyme IspH could solve HMBPP accumulation problem and eliminate the negative effects of ispG overexpression. In addition, intermediate MECPP accumulated in the starting strain, while balanced activation of IspG and IspH could push the carbon flux away from MECPP and led to 73% and 77% increase of β-carotene and lycopene titer respectively. Our work for the first time identified HMBPP to be a cytotoxic intermediate in MEP pathway and demonstrated that balanced activation of IspG and IspH could eliminate accumulation of HMBPP and MECPP and improve isoprenoids production. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  7. Final Technical Report [Development of Catalytic Alkylation and Fluoroalkylation Methods

    Energy Technology Data Exchange (ETDEWEB)

    Vicic, David A.

    2014-05-01

    In the early stages of this DOE-funded research project, we sought to prepare and study a well-defined nickel-alkyl complex containing tridentate nitrogen donor ligands. We found that reaction of (TMEDA)NiMe2 (1) with terpyridine ligand cleanly led to the formation of (terpyridyl)NiMe (2), which we also determined to be an active alkylation catalyst. The thermal stability of 2 was unlike that seen for any of the active pybox ligands, and enabled a number of key studies on alkyl transfer reactions to be performed, providing new insights into the mechanism of nickel-mediated alkyl-alkyl cross-coupling reactions. In addition to the mechanistic studies, we showed that the terpyridyl nickel compounds can catalytically cross-couple alkyl iodides in yields up to 98% and bromides in yields up to 46 %. The yields for the bromides can be increased up to 67 % when the new palladium catalyst [(tpy’)Pd-Ph]I is used. The best route to the targeted [(tpy)NiBr] (1) was found to involve the comproportionation reaction of [(dme)NiBr{sub 2}] and [Ni(COD){sub 2}] in the presence of two equivalents of terpyridine. This reaction was driven to high yields of product formation (72 % isolated) by the precipitation of 1 from THF solvent.

  8. Poly(alkyl acrylate) nonparticles

    International Nuclear Information System (INIS)

    Kreuter, J.

    1985-01-01

    This study deals with the preparation of poly(alkyl acrylic) and poly(alkyl cyanocrylic) nanoparticles. Nonoparticles are solid colloidal particles, consisting of macromolecular materials in which drugs or biologically active materials are dissolved, entrapped, and encapsulated, and/or to which the active substance is adsorbed or attached. Poly(alkyl acrylic) nanoparticles are much more slowly biodegradable than poly(alkyl cyanoacrylate) nanoparticles, and are thus more suitable for drug delivery purposes. Poly(methyl methacrylate) is the material of choice for the use of nanoparticles as an adjuvant for vaccines and are produced by emulsifier-free polymerization in aqueous media. The polymerization, which can be initiated with gamma rays or with potassium peroxodisulfate, is described

  9. Basis for calculating technological parameters of preparation of minced salted fish products of intermediate moisture with specified physical and chemical characteristics

    Directory of Open Access Journals (Sweden)

    Stepanenko E. I.

    2016-09-01

    Full Text Available The dependence of water activity on basic physical and chemical characteristics of salted fish products with intermediate moisture has been defined. During the research the product quality has been assessed by the organoleptic method; determination of the water mass fraction has been carried out by the drying method; the salt mass fraction – by the argentometric method; water activity has been measured by a cooled mirror dew-point sensor. Based on experimental data the dependence of Aw on concentration of sodium chloride in the salt semi-finished products of pollock (Theragra chalcogramma, Atlantic herring (Clupea harengus, Baltic cod (Gadus morhua callarias, blue whiting (Micromesistius, pink salmon (Oncorhynchus gorbuscha, horse mackerel (Trachurus trachurus has been established. The empirical formula showing the correlation of the parameter (Aw with mass fraction of sodium chloride and water has been derived; on its basis it is possible to calculate the parameters of semi-finished product in order to obtain a final minced salt product of intermediate moisture with desired microbial stability upon storage. The relations between the salt mass fraction and water mass fraction excluding bacterial spoilage and mold growth has been determined, they make up S ≥ 0,135 ∙ W and S ≥ 0,34 ∙ W respectively, where S – the mass fraction of salt, %, W – the mass fraction of water, %. An example of calculating the required dosage of sodium chloride in the semi-finished minced salmon has been described to produce the finished product with the exactly given values of humidity and water activity. During the process of minced salted fish products' dehydration the basic physical and chemical parameters – the mass fraction of salt and water affecting the water activity (Aw – have been changing. Determination of these parameters' relationship provides the ability to predict the qualitative changes of salted fish products of intermediate moisture

  10. Cytotoxicity of Poly(Alkyl Cyanoacrylate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Einar Sulheim

    2017-11-01

    Full Text Available Although nanotoxicology has become a large research field, assessment of cytotoxicity is often reduced to analysis of one cell line only. Cytotoxicity of nanoparticles is complex and should, preferentially, be evaluated in several cell lines with different methods and on multiple nanoparticle batches. Here we report the toxicity of poly(alkyl cyanoacrylate nanoparticles in 12 different cell lines after synthesizing and analyzing 19 different nanoparticle batches and report that large variations were obtained when using different cell lines or various toxicity assays. Surprisingly, we found that nanoparticles with intermediate degradation rates were less toxic than particles that were degraded faster or more slowly in a cell-free system. The toxicity did not vary significantly with either the three different combinations of polyethylene glycol surfactants or with particle size (range 100–200 nm. No acute pro- or anti-inflammatory activity on cells in whole blood was observed.

  11. Assessment of high temperature nuclear energy storage systems for the production of intermediate and peak-load electric power

    International Nuclear Information System (INIS)

    Fox, E.C.; Fuller, L.C.; Silverman, M.D.

    1977-01-01

    Increased cost of energy, depletion of domestic supplies of oil and natural gas, and dependence on foreign suppliers, have led to an investigation of energy storage as a means to displace the use of oil and gas presently being used to generate intermediate and peak-load electricity. Dedicated nuclear thermal energy storage is investigated as a possible alternative. An evaluation of thermal storage systems is made for several reactor concepts and economic comparisons are presented with conventional storage and peak power producing systems. It is concluded that dedicated nuclear storage has a small but possible useful role in providing intermediate and peak-load electric power

  12. Effect of cellulose crystallinity on the formation of a liquid intermediate and on product distribution during pyrolysis

    NARCIS (Netherlands)

    Wang, Zhouhong; McDonald, Armando G.; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.; Cuba-Torres, Christian M.; Ha, Su; Pecha, Brennan; Garcia-Perez, Manuel

    2013-01-01

    The effect of cellulose crystallinity on the formation of a liquid intermediate and on its thermal degradation was studied thermogravimetrically and by Py-GC/MS using a control cellulose (Avicel, crystallinity at 60.5%) and ball-milled Avicel (low cellulose crystallinity at 6.5%). The crystallinity

  13. 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.

  14. A Novel Synthesis of 1-Acetyl-4-Isopropenyl-1-Cyclopentene by Chemoselective Cyclization of 4-Methyl-3-(Oxobutyl-4-Pentenal: An Important Intermediate for Natural Product Synthesis

    Directory of Open Access Journals (Sweden)

    Castro Fernando de Lima

    1999-01-01

    Full Text Available This article presents the direct oxidation of limonene-oxide 1 with KIO4 in water, which is the best way to obtain the keto-aldehyde 3, an important intermediate in natural product synthesis. The cyclization of keto-aldehyde 3 with acidic Al2O3 proceeds chemoselectively to give ketone 4. These two reactions together increase the overall yield of ketone 4 to about 70% compared to 8% previously reported in the literature¹.

  15. Comparative techno-economic analysis and process design for indirect liquefaction pathways to distillate-range fuels via biomass-derived oxygenated intermediates upgrading: Liquid Transportation Fuel Production via Biomass-derived Oxygenated Intermediates Upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Eric C. D. [National Renewable Energy Laboratory, Golden CO USA; Snowden-Swan, Lesley J. [Pacific Northwest National Laboratory, Richland WA USA; Talmadge, Michael [National Renewable Energy Laboratory, Golden CO USA; Dutta, Abhijit [National Renewable Energy Laboratory, Golden CO USA; Jones, Susanne [Pacific Northwest National Laboratory, Richland WA USA; Ramasamy, Karthikeyan K. [Pacific Northwest National Laboratory, Richland WA USA; Gray, Michel [Pacific Northwest National Laboratory, Richland WA USA; Dagle, Robert [Pacific Northwest National Laboratory, Richland WA USA; Padmaperuma, Asanga [Pacific Northwest National Laboratory, Richland WA USA; Gerber, Mark [Pacific Northwest National Laboratory, Richland WA USA; Sahir, Asad H. [National Renewable Energy Laboratory, Golden CO USA; Tao, Ling [National Renewable Energy Laboratory, Golden CO USA; Zhang, Yanan [National Renewable Energy Laboratory, Golden CO USA

    2016-09-27

    This paper presents a comparative techno-economic analysis (TEA) of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates. The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass to syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. Conversion of biomass-derived syngas to oxygenated intermediates occurs via three different pathways, producing: 1) mixed alcohols over a MoS2 catalyst, 2) mixed oxygenates (a mixture of C2+ oxygenated compounds, predominantly ethanol, acetic acid, acetaldehyde, ethyl acetate) using an Rh-based catalyst, and 3) ethanol from syngas fermentation. This is followed by the conversion of oxygenates/alcohols to fuel-range olefins in two approaches: 1) mixed alcohols/ethanol to 1-butanol rich mixture via Guerbet reaction, followed by alcohol dehydration, oligomerization, and hydrogenation, and 2) mixed oxygenates/ethanol to isobutene rich mixture and followed by oligomerization and hydrogenation. The design features a processing capacity of 2,000 tonnes/day (2,205 short tons) of dry biomass. The minimum fuel selling prices (MFSPs) for the four developing pathways range from $3.40 to $5.04 per gasoline-gallon equivalent (GGE), in 2011 US dollars. Sensitivity studies show that MFSPs can be improved with co-product credits and are comparable to the commercial Fischer-Tropsch benchmark ($3.58/GGE). Overall, this comparative TEA study documents potential economics for the developmental biofuel pathways via mixed oxygenates.

  16. Alkyl and aryl phosphorodiiodidites. Pt. 2

    International Nuclear Information System (INIS)

    Feshchenko, N.G.; Kostina, V.G.

    1976-01-01

    Alkyl phosphorodiiodidites are formed in the reactions of alkyl phosphorodichloridites with lithium iodide. They are stable at -60 to -50 0 . When warmed to 20 0 , they disproportionate with conversion into trialkyl phosphites and phosphorus triiodide. The latter also react together and give alkyl iodides, diphosphorus tetraiodide, and a polymer of unestablished structure. Diaryl and dialkyl phosphoriodidites are stable only in solution at low temperatures. They disproportionate in a similar way to aryl and alkyl phosphorodiiodidites. Alkyl phosphorodiiodidites react with iodine with the formation of alkyl iodides and phosphoryl iodide

  17. Rh(III-Catalyzed, Highly Selectively Direct C–H Alkylation of Indoles with Diazo Compounds

    Directory of Open Access Journals (Sweden)

    Kang Wan

    2016-06-01

    Full Text Available Rh(III-catalyzed regioselective alkylation of indoles with diazo compounds as a highly efficient and atom-economic protocol for the synthesis of alkyl substituted indoles has been developed. The reaction could proceed under mild conditions and afford a series of desired products in good to excellent yields.

  18. Radiation-chemical alkylation of olefines with adamantane

    International Nuclear Information System (INIS)

    Podkhalyuzin, A.T.; Vikulin, V.V.; Morozov, V.A.; Nazarova, M.P.; Vereshchinskii, I.V.

    1977-01-01

    Radiation-chemical alkylation of C 2 to C 4 olefines with adamantane was studied in gas phase at temperatures 270 to 430 0 C. The main reaction product is monoalkyladamantane. The reaction proceeds by a free radical chain mechanism. The effective activation energy is of the order of 8 to 10 kcal/mole. Thermal alkylation was carried out for comparison and the contribution of the thermal component to the radiation-thermal process was estimated. Liquid phase alkylation of hexafluoropropylene with adamantane was studied in the presence of solvents. Under various conditions mono- and di-substituted adamantanes are produced containing fluorine in end groups. These compounds were converted to corresponding fluoroalkenyladamantanes by dehydrofluorination. The kinetic parameters were calculated and physical-chemical data concerning some of the resulting products were determined. (author)

  19. General Allylic C–H Alkylation with Tertiary Nucleophiles

    Science.gov (United States)

    2015-01-01

    A general method for intermolecular allylic C–H alkylation of terminal olefins with tertiary nucleophiles has been accomplished employing palladium(II)/bis(sulfoxide) catalysis. Allylic C–H alkylation furnishes products in good yields (avg. 64%) with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E:Z). For the first time, the olefin scope encompasses unactivated aliphatic olefins as well as activated aromatic/heteroaromatic olefins and 1,4-dienes. The ease of appending allyl moieties onto complex scaffolds is leveraged to enable this mild and selective allylic C–H alkylation to rapidly diversify phenolic natural products. The tertiary nucleophile scope is broad and includes latent functionality for further elaboration (e.g., aliphatic alcohols, α,β-unsaturated esters). The opportunities to effect synthetic streamlining with such general C–H reactivity are illustrated in an allylic C–H alkylation/Diels–Alder reaction cascade: a reactive diene is generated via intermolecular allylic C–H alkylation and approximated to a dienophile contained within the tertiary nucleophile to furnish a common tricyclic core found in the class I galbulimima alkaloids. PMID:24641574

  20. General allylic C-H alkylation with tertiary nucleophiles.

    Science.gov (United States)

    Howell, Jennifer M; Liu, Wei; Young, Andrew J; White, M Christina

    2014-04-16

    A general method for intermolecular allylic C-H alkylation of terminal olefins with tertiary nucleophiles has been accomplished employing palladium(II)/bis(sulfoxide) catalysis. Allylic C-H alkylation furnishes products in good yields (avg. 64%) with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E:Z). For the first time, the olefin scope encompasses unactivated aliphatic olefins as well as activated aromatic/heteroaromatic olefins and 1,4-dienes. The ease of appending allyl moieties onto complex scaffolds is leveraged to enable this mild and selective allylic C-H alkylation to rapidly diversify phenolic natural products. The tertiary nucleophile scope is broad and includes latent functionality for further elaboration (e.g., aliphatic alcohols, α,β-unsaturated esters). The opportunities to effect synthetic streamlining with such general C-H reactivity are illustrated in an allylic C-H alkylation/Diels-Alder reaction cascade: a reactive diene is generated via intermolecular allylic C-H alkylation and approximated to a dienophile contained within the tertiary nucleophile to furnish a common tricyclic core found in the class I galbulimima alkaloids.

  1. Indium-silver- and zinc-silver-mediated barbier-grignard-type alkylation reactions of imines by using unactivated alkyl halides in aqueous media.

    Science.gov (United States)

    Shen, Zhi-Liang; Cheong, Hao-Lun; Loh, Teck-Peng

    2008-01-01

    In the presence of In or Zn/AgI/InCl(3), an efficient and practical method for the Barbier-Grignard-type alkylation reactions of simple imines by using a one-pot condensation of various aldehydes, amines (including the aliphatic and chiral version), and secondary alkyl iodides has been developed. The reaction proceeded more efficiently in water than in organic solvents. Without the use of CuI, it mainly gave the imine self-reductive coupling product, which was not the alkylated product. Good diastereoselectivities (up to 92:8 dr) were obtained when L-valine methyl ester was used as the substrate.

  2. Quinone methides tethered to naphthalene diimides as selective G-quadruplex alkylating agents.

    Science.gov (United States)

    Di Antonio, Marco; Doria, Filippo; Richter, Sara N; Bertipaglia, Carolina; Mella, Mariella; Sissi, Claudia; Palumbo, Manlio; Freccero, Mauro

    2009-09-16

    We have developed novel G-quadruplex (G-4) ligand/alkylating hybrid structures, tethering the naphthalene diimide moiety to quaternary ammonium salts of Mannich bases, as quinone-methide precursors, activatable by mild thermal digestion (40 degrees C). The bis-substituted naphthalene diimides were efficiently synthesized, and their reactivity as activatable bis-alkylating agents was investigated in the presence of thiols and amines in aqueous buffered solutions. The electrophilic intermediate, quinone-methide, involved in the alkylation process was trapped, in the presence of ethyl vinyl ether, in a hetero Diels-Alder [4 + 2] cycloaddition reaction, yielding a substituted 2-ethoxychroman. The DNA recognition and alkylation properties of these new derivatives were investigated by gel electrophoresis, circular dichroism, and enzymatic assays. The alkylation process occurred preferentially on the G-4 structure in comparison to other DNA conformations. By dissecting reversible recognition and alkylation events, we found that the reversible process is a prerequisite to DNA alkylation, which in turn reinforces the G-quadruplex structural rearrangement.

  3. A comparative analysis of mechanisms of fast light particles production in nucleus-nucleus collisions at low and intermediate energies

    CERN Document Server

    Denikin, A S

    2002-01-01

    The dynamics and the mechanisms of formation of pre-equilibrium light particles in nucleus-nucleus collisions at low and intermediate energies are discussed in terms of a classical four-body model. The energy and angular distributions of light particles have been calculated. It has been found that at energies lower than 50A MeV the formation of the most high-energy part of the nuclear spectrum occurs at the expense of the acceleration of light target particles with the mean field of the projectile. The obtained data are in good agreement with available experimental data

  4. Thioimidazolium Ionic Liquids as Tunable Alkylating Agents.

    Science.gov (United States)

    Guterman, Ryan; Miao, Han; Antonietti, Markus

    2018-01-19

    Alkylating ionic liquids based on the thioimidazolium structure combine the conventional properties of ionic liquids, including low melting point and nonvolatility, with the alkylating function. Alkyl transfer occurs exclusively from the S-alkyl position, thus allowing for easy derivatization of the structure without compromising specificity. We apply this feature to tune the electrophilicty of the cation to profoundly affect the reactivity of these alkylating ionic liquids, with a caffeine-derived compound possessing the highest reactivity. Anion choice was found to affect reaction rates, with iodide anions assisting in the alkylation reaction through a "shuttling" process. The ability to tune the properties of the alkylating agent using the toolbox of ionic liquid chemistry highlights the modular nature of these compounds as a platform for alkylating agent design and integration in to future systems.

  5. Chichibabin-type direct alkylation of pyridyl alcohols with alkyl lithium reagents.

    Science.gov (United States)

    Jeffrey, Jenna L; Sarpong, Richmond

    2012-11-02

    Direct C(6) alkylation of pyridyl alcohols can be achieved following an initial deprotonation of the hydroxy group. This transformation, which is believed to occur by a Chichibabin-type alkylation, avoids lateral deprotonation prior to pyridine ring alkylation and gives increased regioselectivity for C(6) over C(4) alkylation.

  6. The effect of alkylating agents on model supported metal clusters

    Energy Technology Data Exchange (ETDEWEB)

    Erdem-Senatalar, A.; Blackmond, D.G.; Wender, I. (Pittsburgh Univ., PA (USA). Dept. of Chemical and Petroleum Engineering); Oukaci, R. (CERHYD, Algiers (Algeria))

    1988-01-01

    Interactions between model supported metal clusters and alkylating agents were studied in an effort to understand a novel chemical trapping technique developed for identifying species adsorbed on catalyst surfaces. It was found that these interactions are more complex than had previously been suggested. Studies were completed using deuterium-labeled dimethyl sulfate (DMS), (CH{sub 3}){sub 2}SO{sub 4}, as a trapping agent to interact with the supported metal cluster ethylidyne tricobalt enneacarbonyl. Results showed that oxygenated products formed during the trapping reaction contained {minus}OCD{sub 3} groups from the DMS, indicating that the interaction was not a simple alkylation. 18 refs., 1 fig., 3 tabs.

  7. Asymmetric synthesis of chiral heterocyclic amino acids via the alkylation of the Ni(II) complex of glycine and alkyl halides.

    Science.gov (United States)

    Chen, Hui; Wang, Jiang; Zhou, Shengbin; Liu, Hong

    2014-09-05

    An investigation into the reactivity profile of alkyl halides has led to the development of a new method for the asymmetric synthesis of chiral heterocyclic amino acids. This protocol involves the asymmetric alkylation of the Ni(II) complex of glycine to form an intermediate, which then decomposes to form a series of valuable chiral amino acids in high yields and with excellent diastereoselectivity. The chiral amino acids underwent a smooth intramolecular cyclization process to afford the valuable chiral heterocyclic amino acids in high yields and enantioselectivities. This result paves the way for the development of a new synthetic method for chiral heterocyclic amino acids.

  8. Safety Assessment of Alkyl PEG Sulfosuccinates as Used in Cosmetics.

    Science.gov (United States)

    Johnson, Wilbur; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-09-01

    The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) reviewed the safety of alkyl polyethylene glycol (PEG) sulfosuccinates, which function in cosmetics mostly as surfactants/cleansing agents. Although these ingredients may cause ocular and skin irritation, dermal penetration is unlikely because of the substantial polarity and molecular size of these ingredients. The Panel considered the negative oral carcinogenicity and reproductive and developmental toxicity data on chemically related laureths (PEG lauryl ethers) and negative repeated dose toxicity and skin sensitization data on disodium laureth sulfosuccinate supported the safety of these alkyl PEG sulfosuccinates in cosmetic products, but. The CIR Expert Panel concluded that the alkyl PEG sulfosuccinates are safe in the present practices of use and concentration when formulated to be nonirritating. © The Author(s) 2015.

  9. Comprehensive determination of macrolide antibiotics, their synthesis intermediates and transformation products in wastewater effluents and ambient waters by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Senta, Ivan; Krizman-Matasic, Ivona; Terzic, Senka; Ahel, Marijan

    2017-08-04

    Macrolide antibiotics are a prominent group of emerging contaminants frequently found in wastewater effluents and wastewater-impacted aquatic environments. In this work, a novel analytical method for simultaneous determination of parent macrolide antibiotics (azithromycin, erythromycin, clarithromycin and roxithromycin), along with their synthesis intermediates, byproducts, metabolites and transformation products in wastewater and surface water was developed and validated. Samples were enriched using solid-phase extraction on Oasis HLB cartridges and analyzed by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The target macrolide compounds were separated on an ACE C18 PFP column and detected using multiple reaction monitoring in positive ionization polarity. The optimized method, which included an additional extract clean-up on strong anion-exchange cartridges (SAX), resulted in high recoveries and accuracies, low matrix effects and improved chromatographic separation of the target compounds, even in highly complex matrices, such as raw wastewater. The developed method was applied to the analysis of macrolide compounds in wastewater and river water samples from Croatia. In addition to parent antibiotics, several previously unreported macrolide transformation products and/or synthesis intermediates were detected in municipal wastewater, some of them reaching μg/L levels. Moreover, extremely high concentrations of macrolides up to mg/L level were found in pharmaceutical industry effluents, indicating possible importance of this source to the total loads into ambient waters. The results revealed a significant contribution of synthesis intermediates and transformation products to the overall mass balance of macrolides in the aquatic environment. Copyright © 2017. Published by Elsevier B.V.

  10. Synthesis and evaluation of sequence-specific DNA alkylating agents: effect of alkylation subunits.

    Science.gov (United States)

    Shimizu, Tatsuhiko; Sasaki, Shunta; Minoshima, Masafumi; Shinohara, Ken-ichi; Bando, Toshikazu; Sugiyama, Hiroshi

    2006-01-01

    We have demonstrated that hairpin pyrrole (Py)- imidazole (Im) polyamide-CBI conjugates selectively alkylate predetermined sequences. In this study, we investigated the effect of alkylation subunits, for example conjugates 1-4 with three types of DNA alkylating units, and Py-Im polyamides with indole linker. Conjugate 3 and 4 selectively alkylated the predetermined sequences as described previously, while conjugates 1 and 2 alkylate at mismatched sites.

  11. Palladium-catalyzed asymmetric alkylation in the synthesis of cyclopentanoid and cycloheptanoid core structures bearing all-carbon quaternary stereocenters

    KAUST Repository

    Hong, Allen Y.

    2011-12-01

    General catalytic asymmetric routes toward cyclopentanoid and cycloheptanoid core structures embedded in numerous natural products have been developed. The central stereoselective transformation in our divergent strategies is the enantioselective decarboxylative alkylation of seven-membered β-ketoesters to form α-quaternary vinylogous esters. Recognition of the unusual reactivity of β-hydroxyketones resulting from the addition of hydride or organometallic reagents enabled divergent access to γ-quaternary acylcyclopentenes through a ring contraction pathway or γ-quaternary cycloheptenones through a carbonyl transposition pathway. Synthetic applications of these compounds were explored through the preparation of mono-, bi-, and tricyclic derivatives that can serve as valuable intermediates for the total synthesis of complex natural products. This work complements our previous work with cyclohexanoid systems.

  12. An efficient, heterogeneous and reusable catalyst for -alkylation of ...

    Indian Academy of Sciences (India)

    Fe(HSO4)3(FHS) was used as an efficient catalyst for the heterogeneous addition of a series of benzylic and allylic alcohols to various -dicarbonyl compounds, which afforded moderate to excellent yields of -alkylated products in 1,2-dichloroethane. In comparison with the previous methods, the present research ...

  13. Alkylation and dimerisation of 2,6-substituted phenols induced by cobalt-60 gamma radiation in hydrocarbons Part I. Alkylation

    Science.gov (United States)

    Chutný, B.; Brodilová, J.; Pospíšil, J.

    The behavior of 2, 6-substituted phenols in hydrocarbons under the influence of gamma radiation and in the absence of oxygen was studied. Thus 2-methyl-6-tert. butyl phenol in isooctane solution was alkylated in the position 4 and 2-methyl-4-/1, 1, 3, 3- tetramethylbutyl/ -6-tert. butylphenol was formed at a conversion 33%. Among the products also 3, 3-'dimethyl-5, 5-ditert. butyl-4, 4-'biphenyldiol was found. Radiation yields were calculated and some reactions of the alkylation mechanism were proposed.

  14. Investigation of Surface Alkylation Strategy in SOMC: In Situ Generation of a Silica-Supported Tungsten Methyl Catalyst for Cyclooctane Metathesis

    KAUST Repository

    Hamieh, Ali Imad Ali

    2016-07-28

    An efficient and potentially scalable method is described for the synthesis of the silica-supported complexes [(≡Si-O-)WMe5] and [(≡Si-O-)WMe2(≡CH)] obtained by in situ alkylation of the surface-grafted tungsten chloride [(≡Si-O-)WCl5] (1). [(≡Si-O-)WCl5] can be readily prepared by the reaction of commercially available and stable tungsten hexachloride WCl6 with partially dehydroxylated silica at 700 °C (SiO2-700). Further reaction with ZnMe2 at room temperature rapidly forms a mixture of surface-alkylated tungsten complexes. They were fully characterized by microanalysis, FTIR, mass balance, and solid-state NMR (1H, 13C, 1H-13C HETCOR, 1H-1H double quantum and triple quantum) and identified as [(≡Si-O-)WMe5] and another product, [(≡Si-O-)WMe2(≡CH)]. The latter might have been generated by partial decomposition of the tungsten methyl chloride compound, which is formed during the stepwise alkylation of [(≡Si-O-)WCl5]. DFT calculations were carried out to check the relative stability of the tungsten methyl chloride intermediates and the feasibility of the reaction and corroborate the experimental results. This tungsten complex and its derivative were found to be active catalysts for the metathesis of cyclooctane. © 2016 American Chemical Society.

  15. Nitrosation of glycine ethyl ester and ethyl diazoacetate to give the alkylating agent and mutagen ethyl chloro(hydroximino)acetate.

    Science.gov (United States)

    Zhou, Lin; Haorah, James; Chen, Sheng C; Wang, Xiaojie; Kolar, Carol; Lawson, Terence A; Mirvish, Sidney S

    2004-03-01

    Whereas nitrosation of secondary amines produces nitrosamines, amino acids with primary amino groups and glycine ethyl ester were reported to react with nitrite to give unidentified agents that alkylated 4-(p-nitrobenzyl)pyridine to produce purple dyes and be direct mutagens in the Ames test. We report here that treatment of glycine ethyl ester at 37 degrees C with excess nitrite acidified with HCl, followed by ether extraction, gave 30-40% yields of a product identified as ethyl chloro(hydroximino)acetate [ClC(=NOH)COOEt, ECHA] and a 9% yield of ethyl chloroacetate. The ECHA was identical to that synthesized by a known method from ethyl acetoacetate, strongly alkylated nitrobenzylpyridine, and may have arisen by N-nitrosation of glycine ethyl ester to give ethyl diazoacetate, which was C-nitrosated and reacted with chloride to give ECHA. Nitrosation of ethyl diazoacetate also yielded ECHA. Ethyl nitroacetate was not an intermediate as its nitrosation did not produce ECHA. ECHA reacted with aniline to give ethyl (hydroxamino)(phenylimino)acetate [PhN=C(NHOH)CO2Et]. This product was different from ethyl [(phenylamino)carbonyl]carbamate [PhNHC(=O)NHCO2Et], which was synthesized by reacting ethyl isocyanatoformate (OCN.CO2Et) with aniline. ECHA reacted with guanosine to give a derivative, which may have been a guanine-C(=NOH)CO2Et derivative. ECHA showed moderate toxicity and weak but significant mutagenicity without activation in Salmonella typhimurium TA-100 (mean, 1.31 x control value for 12-18 microg/plats) and for V79 mammalian cells (1.5-1.7 x control value for 60-100 microM). In conclusion, gastric nitrosation of glycine derivatives such as peptides with a N-terminal glycine might produce ECHA analogues that alkylate bases of gastric mucosal DNA and thereby initiate gastric cancer.

  16. Unexpected Retroaldol-Aldol Reaction during O-Alkylation of Hydroxylated Vince Lactam Derivatives.

    Science.gov (United States)

    Bengtsson, Christoffer; Wetzel, Alexander; Bergman, Joakim; Brånalt, Jonas

    2016-01-15

    The unexpected retroaldol-aldol reaction during O-alkylation of a β-hydroxy lactam was found to be highly dependent on the temperature and shows a remarkable solvent effect. In DMF, O-alkylation is faster than retroaldol-aldol rearrangement giving exclusively products with retention of configuration. In THF, O-alkylation is slower than rearrangement, giving selectively products with inversion of stereochemistry. In DMSO, a retroaldol reaction followed by fast intramolecular proton transfer occurs to give the ring-opened aldehyde.

  17. An in-situ FTIR study of the side-chain alkylation of toluene with methanol

    International Nuclear Information System (INIS)

    King, S.T.; Garces, J.

    1985-01-01

    The side-chain alkylation of toluene with methanol to styrene and ethylbenzene can be an economically attractive industrial process if it has high enough conversion and selectivity. This process has been investigated by many others using zeolites or metal oxides as the catalyst. It has been generally accepted that high basicity in certain size pores in the catalyst is required for such side-chain alkylation. However, the actual reaction mechanism is still not understood. In this paper the results of an in-situ FT-IR study of the side-chain alkylation in Li, Na, K, Rb and Cs exchanged X zeolites is discussed. It was found that the KX, RbX and CsX zeolites, which are capable of side-chain alkylation, also form surface formate and a surface precursor of formate from methanol decomposition. While the surface formate itself is not the alkylation agent, the observed formate precursor may be the intermediate for side-chain alkylation

  18. Single turnover of substrate-bound ferric cysteine dioxygenase with superoxide anion: enzymatic reactivation, product formation, and a transient intermediate.

    Science.gov (United States)

    Crawford, Joshua A; Li, Wei; Pierce, Brad S

    2011-11-29

    Cysteine dioxygenase (CDO) is a non-heme mononuclear iron enzyme that catalyzes the O(2)-dependent oxidation of L-cysteine (Cys) to produce cysteine sulfinic acid (CSA). In this study we demonstrate that the catalytic cycle of CDO can be "primed" by one electron through chemical oxidation to produce CDO with ferric iron in the active site (Fe(III)-CDO, termed 2). While catalytically inactive, the substrate-bound form of Fe(III)-CDO (2a) is more amenable to interrogation by UV-vis and EPR spectroscopy than the 'as-isolated' Fe(II)-CDO enzyme (1). Chemical-rescue experiments were performed in which superoxide (O(2)(•-)) anions were introduced to 2a to explore the possibility that a Fe(III)-superoxide species represents the first intermediate within the catalytic pathway of CDO. In principle, O(2)(•-) can serve as a suitable acceptor for the remaining 3-electrons necessary for CSA formation and regeneration of the active Fe(II)-CDO enzyme (1). Indeed, addition of O(2)(•-) to 2a resulted in the rapid formation of a transient species (termed 3a) observable at 565 nm by UV-vis spectroscopy. The subsequent decay of 3a is kinetically matched to CSA formation. Moreover, a signal attributed to 3a was also identified using parallel mode X-band EPR spectroscopy (g ~ 11). Spectroscopic simulations, observed temperature dependence, and the microwave power saturation behavior of 3a are consistent with a ground state S = 3 from a ferromagnetically coupled (J ~ -8 cm(-1)) high-spin ferric iron (S(A) = 5/2) with a bound radical (S(B) = 1/2), presumably O(2)(•-). Following treatment with O(2)(•-), the specific activity of recovered CDO increased to ~60% relative to untreated enzyme.

  19. Synthetic resin-bound truncated Candida antarctica lipase B for production of fatty acid alkyl esters by transesterification of corn and soybean oils with ethanol or butanol.

    Science.gov (United States)

    Hughes, Stephen R; Moser, Bryan R; Robinson, Samantha; Cox, Elby J; Harmsen, Amanda J; Friesen, Jon A; Bischoff, Kenneth M; Jones, Marjorie A; Pinkelman, Rebecca; Bang, Sookie S; Tasaki, Ken; Doll, Kenneth M; Qureshi, Nasib; Liu, Siqing; Saha, Badal C; Jackson, John S; Cotta, Michael A; Rich, Joseph O; Caimi, Paolo

    2012-05-31

    A gene encoding a synthetic truncated Candida antarctica lipase B (CALB) was generated via automated PCR and expressed in Saccharomyces cerevisiae. Western blot analysis detected five truncated CALB variants, suggesting multiple translation starts from the six in-frame ATG codons. The longest open reading frame, which corresponds to amino acids 35-317 of the mature lipase, appeared to be expressed in the greatest amount. The truncated CALB was immobilized on Sepabeads® EC-EP resin and used to produce ethyl and butyl esters from crude corn oil and refined soybean oil. The yield of ethyl esters was 4-fold greater from corn oil than from soybean oil and was 36% and 50% higher, respectively, when compared to a commercially available lipase resin (Novozym 435) using the same substrates. A 5:1 (v/v) ratio of ethanol to corn oil produced 3.7-fold and 8.4-fold greater yields than ratios of 15:1 and 30:1, respectively. With corn oil, butyl ester production was 56% higher than ethyl ester production. Addition of an ionic catalytic resin step prior to the CALB resin increased yields of ethyl esters from corn oil by 53% compared to CALB resin followed by ionic resin. The results suggest resin-bound truncated CALB has potential application in biodiesel production using biocatalysts. Published by Elsevier B.V.

  20. Complex responses to alkylating agents

    International Nuclear Information System (INIS)

    Samson, L.D.

    2003-01-01

    Using Affymetrix oligonucleotide GeneChip analysis, we previously found that, upon exposure to the simple alkylating agent methylmethane sulfonate, the transcript levels for about one third of the Saccharomyces cerevisiae genome (∼2,000 transcripts) are induced or repressed during the first hour or two after exposure. In order to determine whether the responsiveness of these genes has any relevance to the protection of cells against alkylating agents we have undertaken several follow-up studies. First, we explored the specificity of this global transcriptional response to MMS by measuring the global response of S. cerevisiae to a broad range of agents that are known to induce DNA damage. We found that each agent produced a very different mRNA transcript profile, even though the exposure doses produced similar levels of toxicity. We also found that the selection of genes that respond to MMS is highly dependent upon what cell cycle phase the cells are in at the time of exposure. Computational clustering analysis of the dataset derived from a large number of exposures identified several promoter motifs that are likely to control some of the regulons that comprise this large set of genes that are responsive to DNA damaging agents. However, it should be noted that these agents damage cellular components other than DNA, and that the responsiveness of each gene need not be in response to DNA damage per se. We have also begun to study the response of other organisms to alkylating agents, and these include E. coli, cultured mouse and human cells, and mice. Finally, we have developed a high throughput phenotypic screening method to interrogate the role of all non-essential S. cerevisiae genes (about 4,800) in protecting S. cerevisiae against the deleterious effects of alkylating agents; we have termed this analysis 'genomic phenotyping'. This study has uncovered a plethora of new pathways that play a role in the recovery of eukaryotic cells after exposure to toxic

  1. PREPARATION OF ALKYL PYROPHOSPHATE EXTRACTANTS

    Science.gov (United States)

    Levine, C.A.; Skiens, W.E.; Moore, G.R.

    1960-08-01

    A process for providing superior solvent extractants for metal recovery processes is given wherein the extractant comprises an alkyl pyrophosphoric acid ester dissolved in an organic solvent diluent. Finely divided solid P/sub 2/O/ sub 5/ is slurried in an organic solvent-diluent selected from organic solvents such as kerosene, benzene, chlorobenzene, toluene, etc. An alcohol selected from the higher alcohols having 4 to 17 carbon atoms. e.g.. hexanol-1. heptanol-3, octanol-1. 2.6-dimethyl-heptanol-4, and decanol-1, is rapidly added to the P/sub 2/O/sub 5/ slurry in the amount of about 2 moles of alcohol to 1 mole of P/sub 2/ O/sub 5/. The temperature is maintained below about 110 deg C during the course of the P/sub 2/O/sub 5/-alcohol reaction. An alkyl pyrophosphate extractant compound is formed as a consequence of the reaction process. The alkyl pyrophosphate solvent-diluent extractant phase is useful in solvent extraction metal recovery processes.

  2. Coordinative saturation and the chemistry of triscyclopentadienyl thorium (IV) alkyls and alkenyls

    International Nuclear Information System (INIS)

    Wachter, W.A.

    1976-01-01

    Air- and moisture-sensitive (C 5 H 5 ) 3 Th(IV)R compounds (R = alkyl, alkenyl) were prepared by reacting (C 5 H 5 ) 3 Th(IV)Cl with the corresponding Grignard or lithium reagent in toluene at -78 0 . They were characterized by elemental analysis, molecular weight, and pmr, infrared, and Raman spectroscopy. The fluxional behavior in the nmr indicates a sigmatropic rearrangement with an activation energy of 8 to 9 kcal/mole. Alcoholysis is faster and more selective for alkane formation than in the analogous uranium system. In aromatic solvents the compounds exhibit first-order decomposition kinetics. Relative thermal stabilities are neopentyl > allyl > n-butyl > 2-cis-2-butenyl > 2-trans-2-butenyl > i-propyl. Respective half-lives of these compounds at 167 0 C are 7500, 566, 96, 39, 21, and 7 hr. Alkanes are the major product for R = alkyl. Retention of configuration is noted for R = cis- and trans-2-butenyl. k/sub H//k/sub D/ is 2.4 for R = n-butyl. The results are consistent with coordinative saturation about the Th center blocking β-elimination. The solid product was also crystallized, and x-ray diffraction results reveal a bridged dimer ((C 5 H 5 ) 2 (C 5 H 4 )Th) 2 . To each Th are bound three rings in a pentahapto fashion and one ring, which is bound in a pentahapto fashion to the other Th center, in a monohapto fashion. These results suggest a short-lived intermediate, possibly an ylid, prior to dimerization. The photochemical decomposition of triscyclopentadienyl Th(IV) isopropyl leads to the formation of propene, propane, and an insoluble green solid. The solid analyzes as (C 15 H 15 Th) 2 , has a temperature-independent paramagnetism of 18.45 x 10 -4 cgs, and exhibits vibrational frequencies characteristic of pentahaptocyclopentadienyl ligands

  3. Bcs1p can rescue a large and productive cytochrome bc(1) complex assembly intermediate in the inner membrane of yeast mitochondria.

    Science.gov (United States)

    Conte, Laura; Trumpower, Bernard L; Zara, Vincenzo

    2011-01-01

    The yeast cytochrome bc(1) complex, a component of the mitochondrial respiratory chain, is composed of ten distinct protein subunits. In the assembly of the bc(1) complex, some ancillary proteins, such as the chaperone Bcs1p, are actively involved. The deletion of the nuclear gene encoding this chaperone caused the arrest of the bc(1) assembly and the formation of a functionally inactive bc(1) core structure of about 500-kDa. This immature bc(1) core structure could represent, on the one hand, a true assembly intermediate or, on the other hand, a degradation product and/or an incorrect product of assembly. The experiments here reported show that the gradual expression of Bcs1p in the yeast strain lacking this protein was progressively able to rescue the bc(1) core structure leading to the formation of the functional homodimeric bc(1) complex. Following Bcs1p expression, the mature bc(1) complex was also progressively converted into two supercomplexes with the cytochrome c oxidase complex. The capability of restoring the bc(1) complex and the supercomplexes was also possessed by the mutated yeast R81C Bcsp1. Notably, in the human ortholog BCS1L, the corresponding point mutation (R45C) was instead the cause of a severe bc(1) complex deficiency. Differently from the yeast R81C Bcs1p, two other mutated Bcs1p's (K192P and F401I) were unable to recover the bc(1) core structure in yeast. This study identifies for the first time a productive assembly intermediate of the yeast bc(1) complex and gives new insights into the molecular mechanisms involved in the last steps of bc(1) assembly. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. A Novel and Chemoselective Process of N-Alkylation of Aromatic Nitrogen Compounds Using Quaternary Ammonium Salts as Starting Material

    Directory of Open Access Journals (Sweden)

    Carlos A. González-González

    2017-01-01

    Full Text Available The process of N-alkylation of several pyrroles, indoles, and derivative heterocycles is herein described, using quaternary ammonium salts as the source of an alkylating agent. These reactions were carried out on several heterocyclic rings with triethylbenzylammonium chloride or tetradecyltrimethylammonium bromide and an NaOH solution at 50%, leading to a chemoselective N-alkylated product and an average yield of 73%. This is an alternative process to the traditional benzylation and methylation of N-heterocycles with direct handling of alkyl halides.

  5. Tandem Three-Component Reactions of Aldehyde, Alkyl Acrylate, and Dialkylmalonate Catalyzed by Ethyl Diphenylphosphine

    Directory of Open Access Journals (Sweden)

    Utpal Das

    2012-03-01

    Full Text Available A new highly efficient three-component reaction of alkyl acrylate, aldehyde and dialkyl malonate using ethyl diphenylphosphine as organocatalyst has been described. Various highly functional compounds bearing hydroxyl groups and the ester functions can be easily prepared in moderate to good yields according to our one-step procedure. The reactions are believed to proceed via Morita-Baylis-Hillman reactions of alkyl acrylate and aldehydes, followed by the Michael addition reactions of dialkyl malonates. Our reactions indicated that the intermediate species formed in the phosphine-catalyzed MBH reaction are an effective organic base to catalyze the Michael addition reactions of dialkyl malonates to the preformed MBH adducts.

  6. Griseorhodins D-F, neuroactive intermediates and end products of post-PKS tailoring modification in Griseorhodin biosynthesis.

    Science.gov (United States)

    Lin, Zhenjian; Zachariah, Malcolm M; Marett, Lenny; Hughen, Ronald W; Teichert, Russell W; Concepcion, Gisela P; Haygood, Margo G; Olivera, Baldomero M; Light, Alan R; Schmidt, Eric W

    2014-05-23

    The griseorhodins belong to a family of extensively modified aromatic polyketides that exhibit activities such as inhibition of HIV reverse transcriptase and human telomerase. The vast structural diversity of this group of polyketides is largely introduced by enzymatic oxidations, which can significantly influence the bioactivity profile. Four new compounds, griseorhodins D-F, were isolated from a griseorhodin producer, Streptomyces sp. CN48+, based upon their enhancement of calcium uptake in a mouse dorsal root ganglion primary cell culture assay. Two of these compounds, griseorhodins D1 and D2, were shown to be identical to the major, previously uncharacterized products of a grhM mutant in an earlier griseorhodin biosynthesis study. Their structures enabled the establishment of a more complete hypothesis for the biosynthesis of griseorhodins and related compounds. The other two compounds, griseorhodins E and F, represent new products of post-polyketide synthase tailoring in griseorhodin biosynthesis and showed significant binding activity in a human dopamine active transporter assay.

  7. Regional ceramic production and distribution systems during the late intermediate ceramic period in central Chile based on NAA

    International Nuclear Information System (INIS)

    Falabella, F.; Andonie, O.

    2003-01-01

    This research focused on the pre-Hispanic ceramic production and distribution systems of the Maipo region in central Chile by means of determining the concentration of the chemical elements in pottery of the Aconcagua culture (900-1450 A.D.) with instrumental neutron activation analysis (INAA). Pottery fragments from eight archaeological sites and natural clays from the study region were included. The differences in chemical composition between subsets of the sample (sites, paste group and ceramic type) were interpreted as indicators of resource and ceramic production locations as well as the imprint of the geological background. These results contributed to the understanding of the Aconcagua ceramic assemblage and helped to test some hypotheses about the Aconcagua social organization. (author)

  8. Conversion of 1-alkyl-2-acetyl-sn-glycerols to platelet activating factor and related phospholipids by rabbit platelets

    International Nuclear Information System (INIS)

    Blank, M.L.; Lee, T.; Cress, E.A.; Malone, B.; Fitzgerald, V.; Snyder, F.

    1984-01-01

    The metabolic pathway for 1-alkyl-2-acetyl-sn-glycerols, a recently discovered biologically active neutral lipid class, was elucidated in experiments conducted with rabbit platelets. The total lipid extract obtained from platelets incubated with 1-[1-,2- 3 H]alkyl-2-acetyl-sn-glycerols or 1-alkyl-2-[ 3 H]acetyl-sn-glycerols contained at least six metabolic products. The six metabolites, identified on the basis of chemical and enzymatic reactions combined with thin-layer or high-performance liquid chromatographic analyses, corresponded to 1-alkyl-sn-glycerols, 1-alkyl-2-acetyl-sn-glycero-3-phosphates, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphocholines, and 1-alkyl-2-actyl-sn-glycero-3-phosphocholines (platelet activating factor). These results indicate that the metabolic pathway for alkylacetylglycerols involves reaction steps catalyzed by the following enzymatic activities: choline- and ethanolamine- phosphotransferases, acetyl-hydrolase, an acyltransferase, and a phosphotransferase. The step responsible for the biosynthesis of platelet activating factor would appear to be the most important reaction in this pathway and this product could explain the hypotensive activities previously described for alkylacetyl-(or propionyl)-glycerols. Of particular interest was the preference exhibited for the utilization of the 1-hexadecyl-2-acetyl-sn-glycerol species in the formation of platelet activating factor

  9. Demonstration of Parallel Algal Processing: Production of Renewable Diesel Blendstock and a High-Value Chemical Intermediate

    Energy Technology Data Exchange (ETDEWEB)

    Knoshaug, Eric P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mohagheghi, Ali [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagle, Nicholas J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Stickel, Jonathan J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dong, Tao [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Karp, Eric M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kruger, Jacob S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brandner, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Manker, Lorenz [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rorrer, Nicholas [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hyman, Deborah A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Christensen, Earl D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pienkos, Philip T [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-19

    Co-production of high-value chemicals such as succinic acid from algal sugars is a promising route to enabling conversion of algal lipids to a renewable diesel blendstock. Biomass from the green alga Scenedesmus acutus was acid pretreated and the resulting slurry separated into its solid and liquor components using charged polyamide induced flocculation and vacuum filtration. Over the course of a subsequent 756 hours continuous fermentation of the algal liquor with Actinobacillus succinogenes 130Z, we achieved maximum productivity, process conversion yield, and titer of 1.1 g L-1 h-1, 0.7 g g-1 total sugars, and 30.5 g L-1 respectively. Succinic acid was recovered from fermentation media with a yield of 60% at 98.4% purity while lipids were recovered from the flocculated cake at 83% yield with subsequent conversion through deoxygenation and hydroisomerization to a renewable diesel blendstock. This work is a first-of-its-kind demonstration of a novel integrated conversion process for algal biomass to produce fuel and chemical products of sufficient quality to be blend-ready feedstocks for further processing.

  10. Cytotoxicity of alkylating agents towards sensitive and resistant strains of Escherichia coli in relation to extent and mode of alkylation of cellular macromolecules and repair of alkylation lesions in deoxyribonucleic acids.

    Science.gov (United States)

    Lawley, P D; Brookes, P

    1968-09-01

    1. A quantitative study was made of the relationship between survival of colony-forming ability in Escherichia coli strains B/r and B(s-1) and the extents of alkylation of cellular DNA, RNA and protein after treatment with mono- or di-functional sulphur mustards, methyl methanesulphonate or iodoacetamide. 2. The mustards and methyl methanesulphonate react with nucleic acids in the cells, in the same way as found previously from chemical studies in vitro, and with proteins. Iodoacetamide reacts only with protein, principally with the thiol groups of cysteine residues. 3. The extents of alkylation of cellular constituents required to prevent cell division vary widely according to the strain of bacteria and the nature of the alkylating agent. 4. The extents of alkylation of the sensitive and resistant strains at a given dose of alkylating agent do not differ significantly. 5. Removal of alkyl groups from DNA of cells of the resistant strains B/r and 15T(-) after alkylation with difunctional sulphur mustard was demonstrated; the product di(guanin-7-ylethyl) sulphide, characteristic of di- as opposed to mono-functional alkylation, was selectively removed; the time-scale of this effect suggests an enzymic rather than a chemical mechanism. 6. The sensitive strain B(s-1) removed alkyl groups from DNA in this way only at very low extents of alkylation. When sensitized to mustard action by treatment with iodoacetamide, acriflavine or caffeine, the extent of alkylation of cellular DNA corresponding to a mean lethal dose was decreased to approximately 3 molecules of di(guanin-7-ylethyl) sulphide in the genome of this strain. 7. Relatively large numbers of monofunctional alkylations per genome can be withstood by this sensitive strain. Iodoacetamide had the weakest cytotoxic action of the agents investigated; methyl methanesulphonate was significantly weaker in effect than the monofunctional sulphur mustard, which was in turn weaker than the difunctional sulphur mustard. 8

  11. Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste.

    Science.gov (United States)

    Diesen, Veronica; Forsberg, Kerstin; Jonsson, Mats

    2017-10-15

    The deep repository for low and intermediate level radioactive waste SFR in Sweden will contain large amounts of cellulosic waste materials contaminated with radionuclides. Over time the repository will be filled with water and alkaline conditions will prevail. In the present study degradation of cellulosic materials and the ability of cellulosic degradation products to solubilize and thereby mobilise Eu(III) under repository conditions has been investigated. Further, the possible immobilization of Eu(III) by sorption onto cement in the presence of degradation products has been investigated. The cellulosic material has been degraded under anaerobic and aerobic conditions in alkaline media (pH: 12.5) at ambient temperature. The degradation was followed by measuring the total organic carbon (TOC) content in the aqueous phase as a function of time. After 173days of degradation the TOC content is highest in the anaerobic artificial cement pore water (1547mg/L). The degradation products are capable of solubilising Eu(III) and the total europium concentration in the aqueous phase was 900μmol/L after 498h contact time under anaerobic conditions. Further it is shown that Eu(III) is adsorbed to the hydrated cement to a low extent (<9μmol Eu/g of cement) in the presence of degradation products. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Experimental Study of W Z Intermediate Bosons Associated Production with the CDF Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Pozzobon, Nicola; /Pisa U.

    2007-09-01

    Studying WZ associated production at the Fermilab Tevatron Collider is of great importance for two main reasons. On the one hand, this process would be sensitive to anomalies in the triple gauge couplings such that any deviation from the value predicted by the Standard Model would be indicative of new physics. In addition, by choosing to focus on the final state where the Z boson decays to b{bar b} pairs, the event topology would be the same as expected for associated production of a W and a Standard Model light Higgs boson (m{sub H} {approx}< 135 GeV) which decays into b{bar b} pairs most of times. The process WH {yields} W b{bar b} has an expected {sigma} {center_dot} B about five times lower than WZ {yields} Wb{bar b} for m{sub H} {approx_equal} 120 GeV. Therefore, observing this process would be a benchmark for an even more difficult search aiming at discovering the light Higgs in the WH {yields} Wb{bar b} process. After so many years of Tevatron operation only a weak WZ signal was recently observed in the full leptonic decay channel, which suffers from much less competition from background. Searching for the Z in the b{bar b} decay channel in this process is clearly a very challenging endeavour. In the work described in this thesis, WZ production is searched for in a final state where the W decays leptonically to an electron-neutrino pair or a muon-neutrino pair, with associated production of a jet pair consistent with Z decays. A set of candidate events is obtained by applying appropriate cuts to the parameters of events collected by wide acceptance leptonic triggers. To improve the signal fraction of the selected events, an algorithm was used to tag b-flavored jets by means of their content of long lived b-hadrons and corrections were developed to the jet algorithm to improve the b-jet energy resolution for a better reconstruction of the Z mass. In order to sense the presence of a signal one needs to estimate the amount of background. The relative content of

  13. Velocity map imaging of O-atom products from UV photodissociation of the CH2OO Criegee intermediate

    Science.gov (United States)

    Li, Hongwei; Fang, Yi; Beames, Joseph M.; Lester, Marsha I.

    2015-06-01

    UV excitation of jet-cooled CH2OO X1A' to the excited B1A' electronic states results in dissociation to two spin-allowed product channels: H2CO X1A1 + O 1D and H2CO a3A″ + O 3P. In this study, the higher energy H2CO a3A″ + O 3P channel is characterized by velocity map imaging and UV action spectroscopy, in both cases utilizing 2 + 1 resonance enhanced multiphoton ionization detection of O 3P products, which complements a prior experimental study on the lower energy H2CO X1A1 + O 1D channel [Lehman et al., J. Chem. Phys. 139, 141103 (2013)]. Anisotropic angular distributions indicative of rapid dissociation are obtained at 330 and 350 nm, along with broad and unstructured total kinetic energy distributions that provide insight into the internal excitation of the H2CO a3A″ co-fragment. A harmonic normal mode analysis points to significant vibrational excitation of the CH2 wag and C-O stretch modes of the H2CO a3A″ fragment upon dissociation. At each UV wavelength, the termination of the kinetic energy distribution reveals the energetic threshold for the H2CO a3A″ + O 3P product channel of ca. 76 kcal mol-1 (378 nm) and also establishes the dissociation energy from CH2OO X1A' to H2CO X1A1 + O1D products of D0 ≤ 49.0 ± 0.3 kcal mol-1, which is in accord with prior theoretical studies. The threshold for the H2CO a3A″ + O 3P channel is also evident as a more rapid falloff on the long wavelength side of the O 3P action spectrum as compared to the previously reported UV absorption spectrum for jet-cooled CH2OO [Beames et al., J. Am. Chem. Soc. 134, 20045 (2012)]. Modeling suggests that the O 3P yield increases uniformly from 378 to 300 nm.

  14. The Scarlet Letter of Alkylation: A Mini Review of Selective Alkylating Agents

    OpenAIRE

    Oronsky, Bryan T; Reid, Tony; Knox, Susan J; Scicinski, Jan J

    2012-01-01

    If there were a stigma scale for chemotherapy, alkylating agents would be ranked at the top of the list. The chemical term alkylation is associated with nonselective toxicity, an association that dates back to the use of nitrogen mustards during World War I as chemical warfare agents. That this stigma persists and extends to compounds that, through selectivity, attempt to “tame” the indiscriminate destructive potential of alkylation is the subject of this review. Selective alkylation, as it i...

  15. Measurement–model comparison of stabilized Criegee intermediate and highly oxygenated molecule production in the CLOUD chamber

    Directory of Open Access Journals (Sweden)

    N. Sarnela

    2018-02-01

    Full Text Available Atmospheric oxidation is an important phenomenon which produces large quantities of low-volatility compounds such as sulfuric acid and oxidized organic compounds. Such species may be involved in the nucleation of particles and enhance their subsequent growth to reach the size of cloud condensation nuclei (CCN. In this study, we investigate α-pinene, the most abundant monoterpene globally, and its oxidation products formed through ozonolysis in the Cosmic Leaving OUtdoor Droplets (CLOUD chamber at CERN (the European Organization for Nuclear Research. By scavenging hydroxyl radicals (OH with hydrogen (H2, we were able to investigate the formation of highly oxygenated molecules (HOMs purely driven by ozonolysis and study the oxidation of sulfur dioxide (SO2 driven by stabilized Criegee intermediates (sCIs. We measured the concentrations of HOM and sulfuric acid with a chemical ionization atmospheric-pressure interface time-of-flight (CI-APi-TOF mass spectrometer and compared the measured concentrations with simulated concentrations calculated with a kinetic model. We found molar yields in the range of 3.5–6.5 % for HOM formation and 22–32 % for the formation of stabilized Criegee intermediates by fitting our model to the measured sulfuric acid concentrations. The simulated time evolution of the ozonolysis products was in good agreement with measured concentrations except that in some of the experiments sulfuric acid formation was faster than simulated. In those experiments the simulated and measured concentrations met when the concentration reached a plateau but the plateau was reached 20–50 min later in the simulations. The results shown here are consistent with the recently published yields for HOM formation from different laboratory experiments. Together with the sCI yields, these results help us to understand atmospheric oxidation processes better and make the reaction parameters more comprehensive for broader use.

  16. Catalytic Alkylation of 2-Methylfuran with Formalin Using Supported Acidic Ionic Liquids

    DEFF Research Database (Denmark)

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song

    2015-01-01

    Biphasic alkylation of 2-methylfuran (2-MF) with formalin was carried out with a series of SBA-15 supported acidic ionic liquid catalysts (acidic SILCs) under mild reaction conditions. Acidic SILC with sulfonic acid groups (SO3H) and long alkyl chains was observed to have higher catalytic activity...... than commercial sulfonic acid resin catalysts for the alkylation reaction in terms of TONs/TOFs as well as selectivity (90%) toward the C11 oxygenate bis(5-methylfuran-2-yl)methane (BMFM). The reaction product was easily separated by addition of the nonpolar solvent n-heptane and additional water...

  17. Enantiomeric separation of pharmaceutically important drug intermediates using a Metagenomic lipase and optimization of its large scale production.

    Science.gov (United States)

    Kumar, Rakesh; Banoth, Linga; Banerjee, Uttam Chand; Kaur, Jagdeep

    2017-02-01

    In the present study, efficient enzymatic methods were developed using a recombinant metagenomic lipase (LipR1) for the synthesis of corresponding esters by the transesterification of five different pharmaceutically important secondary alcohols. The recombinant lipase (specific activity=87m6U/mg) showed maximum conversion in presence of ionic liquid with Naphthyl-ethanol (eeP=99%), Indanol and Methyl-4 pyridine methanol (eeS of 98% and 99%) respectively in 1h. Vinyl acetate was found as suitable acyl donor in transesterification reactions. It was interesting to observe that maximum eeP of 85% was observed in just 15min with 1-indanol. As this enzyme demonstrated pharmaceutical applications, attempts were made to scale up the enzyme production on a pilot scale in a 5litre bioreactor. Different physical parameters affecting enzyme production and biomass concentration such as agitation rate, aeration rate and inoculum concentration were evaluated. Maximum lipase activity of 8463U/ml was obtained at 7h of cultivation at 1 lpm, 300rpm and 1.5% inoculum. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Combining UHPLC-High Resolution MS and Feeding of Stable Isotope Labeled Polyketide Intermediates for Linking Precursors to End Products

    DEFF Research Database (Denmark)

    Klitgaard, Andreas; Frandsen, Rasmus John Normand; Holm, Dorte Koefoed

    2015-01-01

    acid (6-MSA) and 13C14-YWA1, both produced in-house, as well as commercial 13C7-benzoic acid and 2H7-cinnamic acid, in species of Fusarium, Byssochlamys, Aspergillus, and Penicillium. Incorporation of 6-MSA into terreic acid or patulin was not observed in any of six evaluated species covering three...... genera, because the 6-MSA was shunted into (2Z,4E)-2-methyl-2,4-hexadienedioic acid. This indicates that patulin and terreic acid may be produced in a closed compartment of the cell and that (2Z,4E)-2-methyl-2,4-hexadienedioic acid is a detoxification product toward terreic acid and patulin. In Fusarium...... spp., YWA1 was shown to be incorporated into aurofusarin, rubrofusarin, and antibiotic Y. In A. niger, benzoic acid was shown to be incorporated into asperrubrol. Incorporation levels of 0.7–20% into the end-products were detected in wild-type strains. Thus, stable isotope labeling is a promising...

  19. Degradation Kinetics and Mechanism of a β-Lactam Antibiotic Intermediate, 6-Aminopenicillanic Acid, in a New Integrated Production Process.

    Science.gov (United States)

    Su, Min; Sun, Hua; Zhao, Yingying; Lu, Aidang; Cao, Xiaohui; Wang, Jingkang

    2016-01-01

    In an effort to promote sustainability and to reduce manufacturing costs, the traditional production process for 6-aminopenicillanic acid (6-APA) has been modified to include less processing units. The objectives of this study are to investigate the degradation kinetics of 6-APA, to propose a reasonable degradation mechanism, and to optimize the manufacturing conditions within this new process. A series of degradation kinetic studies were conducted in the presence of impurities, as well as at various chemical and physical conditions. The concentrations of 6-APA were determined by high-performance liquid chromatography. An Arrhenius-type kinetic model was established to give a more accurate prediction on the degradation rates of 6-APA. A hydrolysis degradation mechanism is shown to be the major pathway for 6-APA. The degradation mechanisms and the kinetic models for 6-APA in the new system enable the design of a good manufacturing process with optimized parameters. Copyright © 2016. Published by Elsevier Inc.

  20. Electronic Control on Linear versus Branched Alkylation of 2-/3-Aroylbenzofurans with Acrylates: Combined DFT and Synthetic Studies.

    Science.gov (United States)

    Srinivas, Kolluru; Dangat, Yuvraj; Kommagalla, Yadagiri; Vanka, Kumar; Ramana, Chepuri V

    2017-06-01

    Investigations on the factors that govern unusual branched alkylation of 2-aroylbenzofurans with acrylates by Ru-catalyzed carbonyl-directed C-H activation has been carried out by calculating the kinetics associated with the two key steps-the coordination of the acrylate with the intermediate ruthenacycle and the subsequent migratory insertion reaction-studied with the help of DFT calculations. Eight possible orientations for each mode of alkylation have been considered for the calculations. From these calculations, it has been understood that there is a synergistic operation of the steric and electronic effects favoring the branched alkylation. Further DFT investigations on the alkylation of the isomeric 3-aroylbenzofurans indicated a preference for the linear alkylation and this has been verified experimentally. Overall, the observed/calculated complementary selectivity in the alkylation of 2-/3-aroylbenzofurans with acrylates reveals that the substrate-dependent charge distribution of the Ru-C bond in the intermediate ruthenacycle is an important determining factor and thus the current work opens up a new domain of substrate design for controlling regioselectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Enzymatic production of Cilastatin intermediate via highly enantioselective hydrolysis of methyl (±)-2,2-dimethylcyclopropane carboxylate using newly isolated Rhodococcus sp. ECU1013.

    Science.gov (United States)

    Liu, Chao-Hong; Pan, Jiang; Ye, Qin; Xu, Jian-He

    2013-09-01

    (S)-(+)-2,2-Dimethylcyclopropane carboxylic acid [(S)-(+)-DMCPA] is a key chiral intermediate for production of Cilastatin, an excellent renal dehydropeptidase-I inhibitor. In this study, a new method for preparation of (S)-(+)-DMCPA with microbial esterases was investigated. A microbial screening program obtained six esterase-producing isolates that could display relatively high activities and enantioselectivities using racemic ethyl 2,2-dimethylcyclopropane carboxylate (DMCPE) as screening substrate, aiming at forming optically pure (S)-(+)-DMCPA. Further selection was carried out with substrates having different alcohol moieties, including methyl, ethyl, and 2-chloroethyl esters. Finally, one of these strains, numbered ECU1013, with high enantioselectivity toward the hydrolytic resolution of methyl 2,2-dimethylcyclopropane carboxylate (DMCPM), afforded the (S)-product in 92 % ee, and was later identified as Rhodococcus sp. According to our research, there were several active esterases to DMCPM in cells of Rhodococcus sp. ECU1013; however, (S)-preferential esterase was selectively enriched based on the time-dependent profile of esterases biosynthesis, thereby the enantiomeric excess of biotransformation product (ee p) was constantly increased, finally maintained at 95 % (S). To improve the yield, various organic solvents were employed for better dispersion of the hydrophobic substrate. As a result, (±)-DMCPM of up to 400 mM in the organic phase of isooctane was enantioselectively hydrolyzed into (S)-(+)-DMCPA, with an isolation yield of 38 % and a further increase of ee p to 99 %.

  2. Potential of select intermediate-volatility organic compounds and consumer products for secondary organic aerosol and ozone formation under relevant urban conditions

    Science.gov (United States)

    Li, Weihua; Li, Lijie; Chen, Chia-li; Kacarab, Mary; Peng, Weihan; Price, Derek; Xu, Jin; Cocker, David R.

    2018-04-01

    Emissions of certain low vapor pressure-volatile organic compounds (LVP-VOCs) are considered exempt to volatile organic compounds (VOC) regulations due to their low evaporation rates. However, these compounds may still play a role in ambient secondary organic aerosol (SOA) and ozone formation. The LVP-VOCs selected for this work are categorized as intermediate-volatility organic compounds (IVOCs) according to their vapor pressures and molecular formulas. In this study, the evaporation rates of 14 select IVOCs are investigated with half of them losing more than 95% of their mass in less than one month. Further, SOA and ozone formation are presented from 11 select IVOCs and 5 IVOC-containing generic consumer products under atmospherically relevant conditions using varying radical sources (NOx and/or H2O2) and a surrogate reactive organic gas (ROG) mixture. Benzyl alcohol (0.41), n-heptadecane (0.38), and diethylene glycol monobutyl ether (0.16) are determined to have SOA yields greater than 0.1 in the presence of NOx and a surrogate urban hydrocarbon mixture. IVOCs also influence ozone formation from the surrogate urban mixture by impacting radical levels and NOx availability. The addition of lab created generic consumer products has a weak influence on ozone formation from the surrogate mixture but strongly affects SOA formation. The overall SOA and ozone formation of the generic consumer products could not be explained solely by the results of the pure IVOC experiments.

  3. 4-Alkyl radical extrusion in the cytochrome P-450-catalyzed oxidation of 4-alkyl-1,4-dihydropyridines

    International Nuclear Information System (INIS)

    Lee, J.S.; Jacobsen, N.E.; Ortiz de Montellano, P.R.

    1988-01-01

    Rat liver microsomal cytochrome P-450 oxidizes the 4-methyl, 4-ethyl (DDEP), and 4-isopropyl derivatives of 3,5-bis(carbethoxy)-2,6-dimethyl-1,4,-dihydropyridine to mixtures of the corresponding 4-alkyl and 4-dealkyl pyridines. A fraction of the total microsomal enzyme is destroyed in the process. The 4-dealkyl to 4-alkyl pyridine metabolite ratio, the extent of cytochrome P-450 destruction, and the rate of spin-trapped radical accumulation are correlated in a linear inverse manner with the homolytic or heterolytic bond energies of the 4-alkyl groups of the 4-alkyl-1,4-dihydropyridines. No isotope effects are observed on the pyridine matabolite ratio, the destruction of cytochrome P-450, or the formation of ethyl radicals when [4- 2 H]DDEP is used instead of DDEP. N-Methyl- and N-ethyl-DDEP undergo N-dealkylation rather than aromatization but N-phenyl-DDEP is oxidized to a mixture of the 4-ethyl and 4-deethyl N-phenylpyridinium metabolites. In contrast to the absence of an isotope effect in the oxidation of DDEP, the 4-deethyl to 4-ethyl N-phenylpyridinium metabolite ratio increases 6-fold when N-phenyl[4- 2 H]DDEP is used. The results support the hypothesis that cytochrome P-450 catalyzes the oxidation of dihydropyridines to radical cations and show that the radical cations decay to nonradical products by multiple, substituent-dependent, mechanisms

  4. Engineering Isoprenoid Biosynthesis in Artemisia annua L. for the Production of Taxadiene: A Key Intermediate of Taxol

    Directory of Open Access Journals (Sweden)

    Meiya Li

    2015-01-01

    Full Text Available Taxadiene is the first committed precursor to paclitaxel, marketed as Taxol, arguably the most important anticancer agent against ovarian and breast cancer. In Taxus, taxadiene is directly synthesized from geranylgeranyl diphosphate (GGPP that is the common precursor for diterpenoids and is found in most plants and microbes. In this study, Artemisia annua L., a Chinese medicinal herb that grows fast and is rich in terpenoids, was used as a genetic engineering host to produce taxadiene. The TXS (taxadiene synthase gene, cloned from Taxus and inserted into pCAMBIA1304, was transformed into Artemisia annua L. using the Agrobacterium tumefaciens-mediated method. Thirty independent transgenic plants were obtained, and GC-MS analysis was used to confirm that taxadiene was produced and accumulated up to 129.7 μg/g dry mass. However, the high expression of TXS did not affect plant growth or photosynthesis in transgenic Artemisia annua L. It is notable that artemisinin is produced and stored in leaves and most taxadiene accumulated in the stem of transgenic Artemisia annua L., suggesting a new way to produce two important compounds in one transgenic plant: leaves for artemisinin and stem for taxadiene. Overall, this study demonstrates that genetic engineering of the taxane biosynthetic pathway in Artemisia annua L. for the production of taxadiene is feasible.

  5. Photochemical generation and 1H NMR detection of alkyl allene oxides in solution

    International Nuclear Information System (INIS)

    Breen, L.E.; Schepp, N.P.; Tan, C.-H.E.

    2005-01-01

    Irradiation of substituted 5-alkyl-4,5-epoxyvalerophenones leads to the formation of alkyl allene oxides that, in some cases, are sufficiently long-lived to be detected at room temperature by 1 H NMR spectroscopy. Absolute lifetime measurements show that the size of the alkyl group has a significant influence on the reactivity of the allene oxide, with tert-butyl allene oxide having a lifetime of 24 h in CD 3 CN at room temperature that is considerably longer than the 1.5 h lifetime of the ethyl allene oxide. The allene oxides react rapidly with water to give α-hydroxyketones. The mechanism involves nucleophilic attack to the epoxide carbon to give an enol, which can also be detected as an intermediate by 1 H NMR spectroscopy. (author)

  6. Iminium ion chemistry of mitosene DNA alkylating agents. Enriched 13C NMR and isolation studies.

    Science.gov (United States)

    Ouyang, A; Skibo, E B

    2000-05-16

    Described herein is a study of the reductive alkylation chemistry of mitosene antitumor agents. We employed a 13C-enriched electrophilic center to probe the fate of the iminium ion resulting from reductive activation. The 13C-labeled center permitted the identification of complex products resulting from alkylation reactions. In the case of DNA reductive alkylation, the type and number of alkylation sites were readily assessed by 13C NMR. Although there has been much excellent work done in the area of mitosene chemistry and biochemistry, the present study provides a number of new findings: (1) The major fate of the iminium ion is head-to-tail polymerization, even in dilute solutions. (2) Dithionite reductive activation results in the formation of mitosene sulfite esters as well as the previously observed sulfonate adducts. (3) The mitosene iminium ion alkylates the adenosine 6-amino group as well as the guanosine 2-amino group. The identification of the latter adduct was greatly facilitated by the 13C-label at the electrophilic center. (4) The mitosene iminium ion alkylates DNA at both nitrogen and oxygen centers without any apparent base selectivity. The complexity of mitosene reductive alkylation of DNA will require continued adduct isolation studies.

  7. Improving the spectrophotometric determination of the alkylating activity of anticancer agents: a new insight into the mechanism of the NBP method.

    Science.gov (United States)

    Dierickx, Karen M E; Journé, Fabrice; Gerbaux, Pascal; Morandini, Renato; Kauffmann, Jean-Michel; Ghanem, Ghanem E

    2009-02-15

    In this paper, the mechanism of the nitrobenzylpyridine (NBP) method to measure the alkylating activity of drugs originally described by Epstein et al. [J. Epstein, R.W. Rosenthal, R.J. Ess, Anal. Chem. 27 (1955) 1435-1439] and modified later by others was revisited using melphalan, m-sarcolysin, chlorambucil, cyclophosphamide and ifosfamide. Its direct application to determine the activity of these drugs in human serum and aqueous media is described and discussed. This method, based on the formation of a chromophore due to the reaction between the alkylating agent and NBP, was significantly improved by extracting as quickly as possible the reaction product(s) into chloroform before adding alkali to develop the color. This significantly limited the degradation by hydrolysis of the products and enhanced the yield of the end chromophore in the organic phase. The reaction time was optimized by monitoring each compound color development. The best reaction time for each compound was selected and a higher stability of the extracted color over at least 1h was obtained (compared to a couple of minutes in previous studies). Most interestingly, water evaporation due to heating had little or no effect on the linearity of standard curves evaluated in the micromolar concentration range. Both the sensitivity and reproducibility of the method were therefore significantly improved. There appears to be a direct correlation between compound hydrolysis and alkylation activity; the relative reactivity is different among the compounds owing to the rate of (i) production, (ii) the relative proportions and (iii) the hydrolysis of the intermediates. A general mechanism for the nucleophilic competitive substitution is proposed.

  8. Design of novel antitumor DNA alkylating agents: the benzacronycine series.

    Science.gov (United States)

    David-Cordonnier, Marie-Hélène; Laine, William; Gaslonde, Thomas; Michel, Sylvie; Tillequin, Francois; Koch, Michel; Léonce, Stéphane; Pierré, Alain; Bailly, Christian

    2004-03-01

    Acronycine, a natural alkaloid originally extracted from the bark of the Australian ash scrub Acronychia baueri, has shown a significant antitumor activity in animal models. Acronycine has been tested against human cancers in the early 1980s, but the clinical trials showed modest therapeutic effects and its development was rapidly discontinued. In order to optimize the antineoplastic effect, different benzoacronycine derivatives were synthesized. Among those, the di-acetate compound S23906-1 was recently identified as a promising anticancer drug candidate and a novel alkylating agent specifically reacting with the exocylic 2-NH2 group of guanines in DNA. The study of DNA bonding capacity of acronycine derivatives leads to the identification of the structural requirements for DNA alkylation. In nearly all cases, the potent alkylating agents, such as S23906-1, were found to be much more cytotoxic than the unreactive analogs such as acronycine itself or diol derivatives. Alkylation of DNA by the monoacetate derivative S28687-1, which is a highly reactive hydrolysis metabolite of S23906-1, occurs with a marked preference for the N2 position of guanine. Other bionucleophiles can react with S23906-1. The benzacronycine derivatives, which efficiently alkylate DNA, also covalently bind to the tripeptide glutathione (GSH) but not to the oxidized product glutathione disulfide. Here we review the reactivity of S23906-1 and some derivatives toward DNA and GSH. The structure-activity relationships in the benzacronycine series validate the reaction mechanism implicating DNA as the main molecular target. S23906-1 stands as the most promising lead of a medicinal chemistry program aimed at discovering novel antitumor drugs based on the acronycine skeleton.

  9. Conformational Restriction of Peptides Using Dithiol Bis-Alkylation.

    Science.gov (United States)

    Peraro, L; Siegert, T R; Kritzer, J A

    2016-01-01

    Macrocyclic peptides are highly promising as inhibitors of protein-protein interactions. While many bond-forming reactions can be used to make cyclic peptides, most have limitations that make this chemical space challenging to access. Recently, a variety of cysteine alkylation reactions have been used in rational design and library approaches for cyclic peptide discovery and development. We and others have found that this chemistry is versatile and robust enough to produce a large variety of conformationally constrained cyclic peptides. In this chapter, we describe applications, methods, mechanistic insights, and troubleshooting for dithiol bis-alkylation reactions for the production of cyclic peptides. This method for efficient solution-phase macrocyclization is highly useful for the rapid production and screening of loop-based inhibitors of protein-protein interactions. © 2016 Elsevier Inc. All rights reserved.

  10. Method for reactivating solid catalysts used in alkylation reactions

    Science.gov (United States)

    Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

    2003-06-17

    A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

  11. Melamine-bridged alkyl resorcinol modified urea - formaldehyde resin for bonding hardwood plywood

    Science.gov (United States)

    Chung-Yun Hse; Mitsuo Higuchi

    2010-01-01

    A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized...

  12. Ruthenium-catalyzed direct C3 alkylation of indoles with α,β-unsaturated ketones.

    Science.gov (United States)

    Li, Shuai-Shuai; Lin, Hui; Zhang, Xiao-Mei; Dong, Lin

    2015-01-28

    In this paper, a simple and highly efficient ruthenium-catalyzed direct C3 alkylation of indoles with various α,β-unsaturated ketones without chelation assistance has been developed. This novel C-H activation methodology exhibits a broad substrate scope such as different substituted indoles, pyrroles, and other azoles. Further synthetic applications of the alkylation products can lead to more attractive 3,4-fused tricyclic indoles.

  13. Indium-copper-mediated barbier-grignard-type alkylation reaction of imines in aqueous media.

    Science.gov (United States)

    Shen, Zhi-Liang; Loh, Teck-Peng

    2007-12-20

    An efficient system of In/CuI/InCl3 was developed for Barbier-Grignard-type alkylation reactions of simple imines, using a one-pot condensation of various aldehydes, amines (including aliphatic and chiral version), and alkyl iodides in water or aqueous media. The reactions proceeded efficiently at room temperature to give the desired products in moderate to good yields. Good diastereoselectivities were obtained when using L-valine methyl ester as substrate.

  14. S-alkylation of soft scorpionates.

    Science.gov (United States)

    Rajasekharan-Nair, Rajeev; Moore, Dean; Chalmers, Kirsten; Wallace, Dawn; Diamond, Louise M; Darby, Lisa; Armstrong, David R; Reglinski, John; Spicer, Mark D

    2013-02-11

    The alkylation reactions of soft scorpionates are reported. The hydrotris(S-alkyl-methimazolyl)borate dications (alkyl = methyl, allyl, benzyl), which were prepared by the reaction of Tm(Me) anion and primary alkyl halides, have been isolated and structurally characterised. The reaction is, however, not universally successful. DFT analysis of these alkylation reactions (C=S versus B-H alkylation) indicates that the observed outcome is driven by kinetic factors. Extending the study to incorporate alternative imine thiones (mercaptobenzothiazole, bz; thiazoline, tz) led to the structural characterisation of di[aquo-μ-aquohydrotris(mercaptobenzothiazolyl)boratosodium], which contains sodium atoms in the κ(3)-S,S,S coordination mode. Alkylation of Na[Tbz] and Na[tzTtz] leads to decomposition resulting in the formation of the simple S-alkylated heterocycles. The analysis of the species involved in these reactions shows an inherent weakness in the B-N bond in soft scorpionates, which has implications for their use in more advanced chemistry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Isobutane alkylation. Recent developments and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Hommeltoft, Sven Ivar [Haldor Topsoe A/S, Nymoellevej 55, DK-2800 Lyngby (Denmark)

    2001-11-30

    In the isobutane alkylation, alkylated gasoline is obtained which is a valuable blending component for the gasoline pool. Thereby the C{sub 3}-C{sub 4} cut from the FCC units can be extensively used. Established technologies and recent developments will be reviewed and future perspectives will be given.

  16. Rat splenocytes inhibit antigen-specific lymphocyte proliferation through a reactive nitrogen intermediate (RNI)-dependent mechanism and exhibit increased RNI production in response to IFN-gamma.

    Science.gov (United States)

    Stein, C S; Strejan, G H

    1993-09-01

    Rat splenocytes inhibited antigen-specific proliferation of primed lymph node cells in vitro. This inhibition resided in the plastic-adherent splenocyte fraction and was radioresistant, suggesting that the effect was due to macrophages. While this suppression was more evident if spleen cells were derived from immunized rats, spleen cells from normal rats were just as suppressive when added to cocultures at higher numbers. Proliferative responses were greatly enhanced in the presence of NG-monomethyl-L-arginine, a specific inhibitor of the nitric oxide synthetic pathway, and significant levels of nitrite (NO2-), a product of this pathway, were detected in culture supernatants in association with suppressed responses, supporting the notion that suppression was mediated by the L-arginine-dependent production of reactive nitrogen intermediates (RNI). When the splenocytes were physically separated from the responding lymph node cell population, high levels of NO2- were still detected but proliferative responses were no longer inhibited, suggesting that cell proximity or contact is necessary for delivery of the suppressive signal. Adherent splenocytes cultured alone produced low levels of NO2-. Addition of 1 to 50 U/ml IFN-gamma induced a dose-dependent increase in NO2- production, with the maximal level approximating that found in suppressed cocultures; TNF-alpha, IL-2, or LPS did not synergize with IFN-gamma to enhance NO2- production. These findings suggest that by activating macrophages to upregulate RNI synthesis, IFN-gamma-producing T cells may exert a negative influence over their own proliferation.

  17. Seed Priming Alters the Production and Detoxification of Reactive Oxygen Intermediates in Rice Seedlings Grown Under Sub-Optimal Temperature and Nutrient Supply

    Directory of Open Access Journals (Sweden)

    Saddam eHussain

    2016-04-01

    Full Text Available The production and detoxification of reactive oxygen intermediates (ROIs play an important role in the plant response to nutrient and environmental stresses. The present study demonstrated the behavior of growth, ROIs-production and their detoxification in primed and non-primed rice seedlings under chilling stress (18˚C and nitrogen-(N, phosphorus-(P, or potassium-(K deprivation. The results revealed that chilling stress as well as deprivation of any mineral nutrient severely hampered the seedling growth of rice, however, seed priming treatments (particularly selenium- or salicylic acid-priming, were effective in enhancing the rice growth under stress conditions. The N-deprivation caused the maximum reduction in shoot growth, while the root growth was only decreased by P- or K-deprivation. Although, N-deprivation enhanced the root length of rice, the root fresh weight was unaffected. Rate of lipid peroxidation as well as the production of ROIs, was generally increased under stress conditions; the K-deprived seedlings recorded significantly lower production of ROIs than N- or P-deprived seedlings. The responses of enzymatic and non-enzymatic antioxidants in rice seedlings to chilling stress were variable with nutrient management regime. All the seed priming were found to trigger or at least maintain the antioxidant defense system of rice seedlings. Notably, the levels of ROIs were significantly reduced by seed priming treatments, which were concomitant with the activities of ROIs-producing enzymes (monoamine oxidase and xanthine oxidase, under all studied conditions. Based on these findings, we put forward the hypothesis that along with role of ROIs-scavenging enzymes, the greater tolerance of primed rice seedlings can also be due to the reduced activity of ROIs-producing enzymes.

  18. Alkylation of Isobutane/2-Butene Over Modified FAU-Type Zeolites.

    Science.gov (United States)

    Ro, Youngsoo; Gim, Min Yeoung; Lee, Jong Won; Lee, Eo Jin; Song, In Kyu

    2018-09-01

    A serious of mesoporous La-zeolite X catalysts (La-x-Zeol X (x = 0, 0.25, 0.5, 0.75, 1.0, and 2.0)) were prepared by a hydrothermal method with a variation of carbon template content (x, wt%). The prepared catalysts were applied to the isobutane/2-butene alkylation. Mesopore volume of the catalysts increased with increasing carbon template content, while acidity of the catalysts decreased with increasing carbon template content. In the catalytic reaction, productivity of C8 alkylate (C8 alkylate g/g-catalyst) and selectivity for C8 alkylate showed volcano-shaped trends with respect to carbon template content. Among the catalysts, La-0.5-Zeol X showed the highest productivity and selectivity for C8 alkylate. The maximum productivity and selectivity for C8 alkylate over La-0.5-Zeol X were due to the offset of two opposite trends between mesopore volume and acidity of La-x-Zeol X catalysts.

  19. Biocatalytic Synthesis of Chiral Pharmaceutical Intermediates

    Directory of Open Access Journals (Sweden)

    Ramesh N. Patel

    2004-01-01

    Full Text Available The production of single enantiomers of drug intermediates has become increasingly important in the pharmaceutical industry. Chiral intermediates and fine chemicals are in high demand from both the pharmaceutical and agrochemical industries for the preparation of bulk drug substances and agricultural products. The enormous potential of microorganisms and enzymes for the transformation of synthetic chemicals with high chemo-, regio- and enantioselectivities has been demonstrated. In this article, biocatalytic processes are described for the synthesis of chiral pharmaceutical intermediates.

  20. Induction of reactive oxygen intermediates-dependent programmed cell death in human malignant ex vivo glioma cells and inhibition of the vascular endothelial growth factor production by taurolidine.

    Science.gov (United States)

    Rodak, Roksana; Kubota, Hisashi; Ishihara, Hideyuki; Eugster, Hans-Pietro; Könü, Dilek; Möhler, Hanns; Yonekawa, Yasuhiro; Frei, Karl

    2005-06-01

    Taurolidine, a derivative of the amino acid taurin, was recently found to display a potent antineoplastic effect both in vitro and in vivo. The authors therefore initiated studies to assess the potential antineoplastic activity of taurolidine in human glioma cell lines and in ex vivo malignant cell cultures. They also studied the mechanisms that induce cell death and the impact of taurolidine on tumor-derived vascular endothelial growth factor (VEGF) production. Cytotoxicity and clonogenic assays were performed using crystal violet staining. In the cytotoxicity assay 100% of glioma cell lines (eight of eight) and 74% of ex vivo glioma cultures (14 of 19) demonstrated sensitivity to taurolidine, with a mean median effective concentration (EC50) of 51 +/- 28 microg/ml and 56 +/- 23 microg/ml, respectively. Colony formation was inhibited by taurolidine, with a mean EC50 of 7 +/- 3 microg/ml for the cell lines and a mean EC50 of 3.5 +/- 1.7 microg/ml for the ex vivo glioma cultures. On observing this high activity of taurolidine in both assays, the authors decided to evaluate its cell death mechanisms. Fragmentation of DNA, externalization of phosphatidylserine, activation of poly(adenosine diphosphate-ribose) polymerase, loss of the mitochondrial membrane potential followed by a release of apoptosis-inducing factor, and typical apoptotic features were found after taurolidine treatment. Cell death was preceded by the generation of reactive O2 intermediates, which was abrogated by N-acetylcysteine but not by benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Moreover, taurolidine also induced suppression of VEGF production on the protein and messenger RNA level, as shown by an enzyme-linked immunosorbent assay and by reverse transcription-polymerase chain reaction. Given all these findings, taurolidine may be a promising new agent in the treatment of malignant gliomas; it displays a combination of antineoplastic and antiangiogenic activities, inducing tumor cell

  1. Study on the Alkylation Reactions of N(7)-Unsubstituted 1,3-Diazaoxindoles.

    Science.gov (United States)

    Kókai, Eszter; Halász, Judit; Dancsó, András; Nagy, József; Simig, Gyula; Volk, Balázs

    2017-05-19

    The chemistry of the 5,7-dihydro-6 H -pyrrolo[2,3- d ]pyrimidin-6-one (1,3-diazaoxindole) compound family, possessing a drug-like scaffold, is unexplored. In this study, the alkylation reactions of N (7)-unsubstituted 5-isopropyl-1,3-diazaoxindoles bearing various substituents at the C (2) position have been investigated. The starting compounds were synthesized from the C (5)-unsubstituted parent compounds by condensation with acetone and subsequent catalytic reduction of the 5-isopropylidene moiety. Alkylation of the thus obtained 5-isopropyl derivatives with methyl iodide or benzyl bromide in the presence of a large excess of sodium hydroxide led to 5,7-disubstituted derivatives. Use of butyllithium as the base rendered alkylation in the C (5) position possible with reasonable selectivity, without affecting the N (7) atom. During the study on the alkylation reactions, some interesting by-products were also isolated and characterized.

  2. Synthesis of no-carrier-added radiobrominated n-alkylated analogues of spiperone

    International Nuclear Information System (INIS)

    Moerlein, S.M.; Laufer, P.; Stoecklin, G.

    1985-01-01

    The synthesis of a series of p-bromo-3-N-alkyl spiperone analogues is described. N-alkylation was achieved via reaction of the potassium salt of the spiperone lactam ring with alkyl iodide; subsequent reactions with elemental bromine gave the p-brominated isomers. Optimization studies using no-carrier-added (n.c.a.) 77 Br - indicated that radio-bromination of N-alkyl spiperone analogues occurs with higher yields and in shorter reaction times when dichloramine-T (DCT) is used rather than H 2 0 2 /acetic acid as an oxidant. The production of the title compounds in high effective specific activity with radiochemical yields of 20-30 % using n.c.a. 77 Br - and DCT is reported. (author)

  3. N-Alkylation of sulfonamides by alkyl halides in the presence of electrophilic catalysts and transformations of alkylated compounds

    Directory of Open Access Journals (Sweden)

    Larysa V. Dmitrikova

    2016-12-01

    Full Text Available Vicinal halo amines constitute an important class of compounds due to their diverse biological activity and a broad application as synthones in the production of pharmaceutical agents. The reaction of aryl- and alkylsulfonamides with 1,2-dibromo-2-phenylethane in the presence of Lewis acids (such as FeCl3 and ZnCl2 in 1,2-dichloroethane can represent one of the most efficient ways of halo amine synthesis. It has been shown that methanesulfonamides and benzylsulfonamides starting materials produced the alkylation products with good yields while p-toluenesulfonamides appeared to be less active and 6-methyl-3-nitrobenzylsulfonamides did not give the expected compounds. It has been found that synthesized vicinal halo amides can easily cyclize in alkaline conditions to give 1-sulfonylaziridines. The regioselectivity of aziridine ring opening has also been studied. It was established that strong nucleophile attacks terminal carbon which leads to the breaking-up of 1–3 bond and subsequent aziridine ring opening. In contrast, weak nucleophiles (water, potassium rhodanide, hydrogen bromide trigger the cleavage of aziridine cycle by breaking-up of 1–2 bond under acidic conditions which is in accordance with molecular orbital theory. Substituents at the aromatic ring of sulfonyl fragment do not influence on the pathway of aziridine ring opening.

  4. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  5. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  6. Alkylation of isobutane by ethylene: A thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Goupil, J.M.; Poirier, J.L.; Cornet, D. (Univ. of Caen (France). Lab. Catalyse et Spectrochimie)

    1994-03-01

    Alkylation of isobutane by ethylene produces mainly hexanes, but a variety of other compounds, alkanes or alkenes, may be formed by secondary reactions such as successive alkylations, isomerization, and ethylene polymerization. The equilibrium distribution of products is evaluated in the temperature range 280--680 K and at various initial compositions and pressures. Isomer groups are treated using Alberty's formulation. Calculations show that alkenes are thermodynamically unstable under usual reaction conditions. The equilibrium amounts of alkanes are such that C[sub 6] [much gt] C[sub 8] [much gt] C[sub 10] and heavy alkanes also appear unstable. The selective formation of particular isomers (dimethylbutanes, trimethylpentanes) is also integrated in the equilibrium equations. The calculated compositions (C[sub 6]:C[sub 8]:C[sub 10]) are compared with experimental data.

  7. Production of intermediate vector bosons W and Z in proton and anti-protons interactions at 540 GeV in the center of mass

    International Nuclear Information System (INIS)

    Locci, E.

    1984-06-01

    The most important and the most expected result of the s = 540 GeV pantip collider at CERN is the proof of the existence of the weak intermediate bosons W +- and Z 0 , and the study of their properties. This study in the UA1 experiment is presented. 52W + (W - )→e + (e - )νsub(e)(antiνsub(e)) and 4 Z 0 → e + e - have been produced. Their measured masses are Msub(W) = 80.9sub(-1.4)sup(+0.6) GeV/c 2 et Msub(Z) = 95.6 +- 1.4 GeV/c 2 . Their properties are entirely consistent with the ''standard model'' and their characteristics of production are consistent with QCD expectations. The relative numbers of W → eνsub(e) and Z → e + e - , as well as the width of the Z, give an upper limit of the number of ''generations'' [fr

  8. Biodegradation of sulfamethazine by Trametes versicolor: Removal from sewage sludge and identification of intermediate products by UPLC-QqTOF-MS

    International Nuclear Information System (INIS)

    Garcia-Galan, Ma. Jesus; Rodriguez-Rodriguez, Carlos E.; Vicent, Teresa; Caminal, Gloria; Diaz-Cruz, M. Silvia; Barcelo, Damia

    2011-01-01

    Degradation of the sulfonamide sulfamethazine (SMZ) by the white-rot fungus Trametes versicolor was assessed. Elimination was achieved to nearly undetectable levels after 20 h in liquid medium when SMZ was added at 9 mg L -1 . Experiments with purified laccase and laccase-mediators resulted in almost complete removal. On the other hand, inhibition of SMZ degradation was observed when piperonilbutoxide, a cytochrome P450-inhibitor, was added to the fungal cultures. UPLC-QqTOF-MS analysis allowed the identification and confirmation of 4 different SMZ degradation intermediates produced by fungal cultures or purified laccase: desulfo-SMZ, N 4 -formyl-SMZ, N 4 -hydroxy-SMZ and desamino-SMZ; nonetheless SMZ mineralization was not demonstrated with the isotopically labeled sulfamethazine-phenyl- 13 C 6 after 7 days. Inoculation of T. versicolor to sterilized sewage sludge in solid-phase systems showed complete elimination of SMZ and also of other sulfonamides (sulfapyridine, sulfathiazole) at real environmental concentrations, making this fungus an interesting candidate for further remediation research. - Highlights: →Degradation of sulfamethazine by Trametes versicolor was evaluated. →The laccase enzymatic system and cytochrome P-450 were involved in the degradation. →Four different degradation products of sulfamethazine were identified and confirmed. →The molecular structures and masses of the metabolites were accurately calculated. →Full elimination of sulfamethazine was observed in regular sewage sludge.

  9. Coordinative Modulation of Chlorothricin Biosynthesis by Binding of the Glycosylated Intermediates and End Product to a Responsive Regulator ChlF1.

    Science.gov (United States)

    Li, Yue; Li, Jingjing; Tian, Zhenhua; Xu, Yu; Zhang, Jihui; Liu, Wen; Tan, Huarong

    2016-03-04

    Chlorothricin, isolated from Streptomyces antibioticus, is a parent member of spirotetronate family of antibiotics that have long been appreciated for their remarkable biological activities. ChlF1 plays bifunctional roles in chlorothricin biosynthesis by binding to its target genes (chlJ, chlF1, chlG, and chlK). The dissociation constants of ChlF1 to these genes are ∼ 102-140 nm. A consensus sequence, 5'-GTAANNATTTAC-3', was found in these binding sites. ChlF1 represses the transcription of chlF1, chlG, and chlK but activates chlJ, which encodes a key enzyme acyl-CoA carboxyl transferase involved in the chlorothricin biosynthesis. We demonstrate that the end product chlorothricin and likewise its biosynthetic intermediates (demethylsalicycloyl chlorothricin and deschloro-chlorothricin) can act as signaling molecules to modulate the binding of ChlF1 to its target genes. Intriguingly, a correlation between the antibacterial activity and binding ability of signaling molecules to the regulator ChlF1 is clearly observed. These features of the signaling molecules are associated with the glycosylation of spirotetronate macrolide aglycone. The findings provide new insights into the TetR family regulators responding to special structure of signaling molecules, and we reveal the regulatory mini-network mediated by ChlF1 in chlorothricin biosynthesis for the first time. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Coordinative Modulation of Chlorothricin Biosynthesis by Binding of the Glycosylated Intermediates and End Product to a Responsive Regulator ChlF1*

    Science.gov (United States)

    Li, Yue; Li, Jingjing; Tian, Zhenhua; Xu, Yu; Zhang, Jihui; Liu, Wen; Tan, Huarong

    2016-01-01

    Chlorothricin, isolated from Streptomyces antibioticus, is a parent member of spirotetronate family of antibiotics that have long been appreciated for their remarkable biological activities. ChlF1 plays bifunctional roles in chlorothricin biosynthesis by binding to its target genes (chlJ, chlF1, chlG, and chlK). The dissociation constants of ChlF1 to these genes are ∼102–140 nm. A consensus sequence, 5′-GTAANNATTTAC-3′, was found in these binding sites. ChlF1 represses the transcription of chlF1, chlG, and chlK but activates chlJ, which encodes a key enzyme acyl-CoA carboxyl transferase involved in the chlorothricin biosynthesis. We demonstrate that the end product chlorothricin and likewise its biosynthetic intermediates (demethylsalicycloyl chlorothricin and deschloro-chlorothricin) can act as signaling molecules to modulate the binding of ChlF1 to its target genes. Intriguingly, a correlation between the antibacterial activity and binding ability of signaling molecules to the regulator ChlF1 is clearly observed. These features of the signaling molecules are associated with the glycosylation of spirotetronate macrolide aglycone. The findings provide new insights into the TetR family regulators responding to special structure of signaling molecules, and we reveal the regulatory mini-network mediated by ChlF1 in chlorothricin biosynthesis for the first time. PMID:26750095

  11. Biodegradation of sulfamethazine by Trametes versicolor: Removal from sewage sludge and identification of intermediate products by UPLC-QqTOF-MS

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Galan, Ma. Jesus, E-mail: mggqam@cid.csic.es [Departament de Quimica Ambiental, IDAEA-CSIC, C/Jordi Girona 18-26, 08034 Barcelona (Spain); Rodriguez-Rodriguez, Carlos E., E-mail: CarlosEsteban.Rodriguez@uab.cat [Unitat asociada de Biocatalisi Aplicada IQAC-CSIC, Escola d' Enginyeria, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Centro de Investigacion en Contaminacion Ambiental, Universidad de Costa Rica, 2060 San Jose (Costa Rica); Vicent, Teresa, E-mail: Teresa.Vicent@uab.cat [Departament d' Enginyeria Quimica, Escola d' Enginyeria, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Caminal, Gloria, E-mail: Gloria.Caminal@uab.cat [Unitat asociada de Biocatalisi Aplicada IQAC-CSIC, Escola d' Enginyeria, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Diaz-Cruz, M. Silvia, E-mail: sdcqam@cid.csic.es [Departament de Quimica Ambiental, IDAEA-CSIC, C/Jordi Girona 18-26, 08034 Barcelona (Spain); Barcelo, Damia, E-mail: dbcqam@cid.csic.es [Departament de Quimica Ambiental, IDAEA-CSIC, C/Jordi Girona 18-26, 08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), Parc Cientific i Tecnologic de la Universitat de Girona. C/Emili Grahit, 101 Edifici H2O, E-17003 Girona (Spain); King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

    2011-11-15

    Degradation of the sulfonamide sulfamethazine (SMZ) by the white-rot fungus Trametes versicolor was assessed. Elimination was achieved to nearly undetectable levels after 20 h in liquid medium when SMZ was added at 9 mg L{sup -1}. Experiments with purified laccase and laccase-mediators resulted in almost complete removal. On the other hand, inhibition of SMZ degradation was observed when piperonilbutoxide, a cytochrome P450-inhibitor, was added to the fungal cultures. UPLC-QqTOF-MS analysis allowed the identification and confirmation of 4 different SMZ degradation intermediates produced by fungal cultures or purified laccase: desulfo-SMZ, N{sup 4}-formyl-SMZ, N{sup 4}-hydroxy-SMZ and desamino-SMZ; nonetheless SMZ mineralization was not demonstrated with the isotopically labeled sulfamethazine-phenyl-{sup 13}C{sub 6} after 7 days. Inoculation of T. versicolor to sterilized sewage sludge in solid-phase systems showed complete elimination of SMZ and also of other sulfonamides (sulfapyridine, sulfathiazole) at real environmental concentrations, making this fungus an interesting candidate for further remediation research. - Highlights: {yields}Degradation of sulfamethazine by Trametes versicolor was evaluated. {yields}The laccase enzymatic system and cytochrome P-450 were involved in the degradation. {yields}Four different degradation products of sulfamethazine were identified and confirmed. {yields}The molecular structures and masses of the metabolites were accurately calculated. {yields}Full elimination of sulfamethazine was observed in regular sewage sludge.

  12. hf alkylation in the 1980's: the role of isobutane/olefin ratio

    Energy Technology Data Exchange (ETDEWEB)

    Hutson, T. Jr.

    1978-08-01

    Research devoted to maximizing no-lead octane numbers in motor fuel is reported. Results of the studies are the basis for the following conclusions: 1. Isobutane alkylate made from either propylene, butene-2, or C/sub 3/--C/sub 4/ mixed olefins is a low sensitivity, high motor octane product. Typically, C/sub 3/--C/sub 4/ mixed olefin alkylate has a clear motor octane number of about 92.2 and a clear Research octane number of about 93.5. 2. In separate studies with propylene, butene-2 and C/sub 3/--C/sub 4/ mixed olefins, increasing the isobutane-to-olefin ratio suppressed the formation of high molecular weight residue, indicating a substantial reduction in the role of olefin polymerization to large ions. The overall result of increasing ratio was an improvement in selectivity to high-octane components in the alkylate. 3. When alkylating isobutane with propylene, increasing the ratio resulted in a decrease in the concentration of C/sub 7/-fraction (primary product) and an increase in the C/sub 8/-fraction (from chain initiation and subsequent hydrogen transfer). At the same time, the production of chain-termination-product propane also increased. 4. When alkylating isobutane with C/sub 3/--C/sub 4/ mixed olefins, increasing the ratio showed the same trend obtained in separate alkylation tests with propylene and butene-2. As the ratio increased, the concentration of C/sub 7/-fraction (primary propylene--isobutane product) decreased and the concentration of C/sub 8/-fraction increased markedly. Thus, increasing isobutane-to-olefin ratio exerted a strong effect on alkylate quality in the area of about 5 to 1 to 20 to 1; this effect diminished at ratios 20:1.

  13. The effect of UV-C stimulation of potato tubers and soaking of potato strips in water on density differences of intermediates for French-fry production

    Directory of Open Access Journals (Sweden)

    Sobol Zygmunt

    2018-01-01

    Full Text Available The paper describes the effect of UV-C stimulation of potato tubers and immersing of potato strips in water on differences in density of intermediate products for French-fry production. The density difference used for description of the experiment was defined as a relationship between the post-treatment density and pre-treatment density. The study was conducted on tubers of the Innovator variety. The studies of density changes induced by absorption of water involved measurements of the mass of potato strips in air and in water. Potato strips measured 10 × 10 mm and 60 mm in length. The strips were cut lengthwise along the longest tuber axis set between the proximal and distal tuber end. Water absorption was investigated by immersing strips in water (1 at a temperature of 20°C for 15 min and (2 at 40°C for 20 min. In addition, the study included the group (3 where strips were blanched at a temperature of 90°C for 2 min and a control group (0 which was not immersed in water. Potato tubers were irradiated by UV-C in the following ways: (1 irradiation on one side for 30 min, (2 irradiation on both sides for 15 min each, (0 control group (no irradiation. The studies were conducted at two dates: (0 after harvest and (1 after 3-month storage. Laboratory and storage experiments were conducted in 2016-2017. The density difference was statistically significantly influenced by storage time, UV-C stimulation and immersion conditions of potato strips. The density difference increased with the increase in storage duration of tubers, immersion duration of strips, water temperature (up to starch gelification temperature and UV-C stimulation.

  14. UV absorption spectra, kinetics and mechanism for alkyl and alkyl peroxy radicals originating from t-butyl alcohol

    DEFF Research Database (Denmark)

    Langer, S.; Ljungström, E.; Sehested, J.

    1994-01-01

    Alkyl and alkyl peroxy radicals from 1-butyl alcohol (TBA), HOC (CH3)2CH2. and HOC(CH3)2CH2O2. have been studied in the ps phase at 298 K. Two techniques were used: pulse radiolysis UV absorption to measure the spectra and kinetics, and long path-length Fourier transform infrared spectroscopy (FTIR......) and k(HOC(CH3)2CH2O2. + NO2) were determined to be (4.9 +/- 0.9) X 10(-12) and (6.7 +/- 0.9) x 10(-12) cm3 molecule-1 s-1, respectively. In the FTIR experiments products were studied using chlorine-initiated oxidation in TBA/N2/Cl2 and TBA/N2/O2/Cl2 mixtures....

  15. The Barbier-Grignard-type carbonyl alkylation using unactivated alkyl halides in water.

    Science.gov (United States)

    Keh, Charlene C K; Wei, Chunmei; Li, Chao-Jun

    2003-04-09

    The aqueous Barbier-Grignard-type alkylation of aldehydes with unactivated alkyl iodides and bromides was developed. By using a combination of zinc and cuprous iodide, catalyzed by indium(I) chloride, we successfully added tertiary, secondary, and primary alkyl halides to various aromatic aldehydes in 0.07 M aqueous Na2C2O4. A mechanistic rationale for the success of the reaction has been proposed.

  16. Alkylation of human hair keratin for tunable hydrogel erosion and drug delivery in tissue engineering applications.

    Science.gov (United States)

    Han, Sangheon; Ham, Trevor R; Haque, Salma; Sparks, Jessica L; Saul, Justin M

    2015-09-01

    Polymeric biomaterials that provide a matrix for cell attachment and proliferation while achieving delivery of therapeutic agents are an important component of tissue engineering and regenerative medicine strategies. Keratins are a class of proteins that have received attention for numerous tissue engineering applications because, like other natural polymers, they promote favorable cell interactions and have non-toxic degradation products. Keratins can be extracted from various sources including human hair, and they are characterized by a high percentage of cysteine residues. Thiol groups on reductively extracted keratin (kerateine) form disulfide bonds, providing a more stable cross-linked hydrogel network than oxidatively extracted keratin (keratose) that cannot form disulfide crosslinks. We hypothesized that an iodoacetamide alkylation (or "capping") of cysteine thiol groups on the kerateine form of keratin could be used as a simple method to modulate the levels of disulfide crosslinking in keratin hydrogels, providing tunable rates of gel erosion and therapeutic agent release. After alkylation, the alkylated kerateines still formed hydrogels and the alkylation led to changes in the mechanical and visco-elastic properties of the materials consistent with loss of disulfide crosslinking. The alkylated kerateines did not lead to toxicity in MC3T3-E1 pre-osteoblasts. These cells adhered to keratin at levels comparable to fibronectin and greater than collagen. Alkylated kerateine gels eroded more rapidly than non-alkylated kerateine and this control over erosion led to tunable rates of delivery of rhBMP-2, rhIGF-1, and ciprofloxacin. These results demonstrate that alkylation of kerateine cysteine residues provides a cell-compatible approach to tune rates of hydrogel erosion and therapeutic agent release within the context of a naturally-derived polymeric system. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Radical intermediates of low temperature radiolysis of di-tert-butylcyclohexano-18-crown-6/1-octanol extractant

    International Nuclear Information System (INIS)

    Zakurdaeva, O.A.; Nesterov, S.V.; Moscow State Univ.; Feldman, V.I.

    2013-01-01

    Intermediates of low temperature (77 K) X-rays radiolysis of 1-octanol and di-tert-butylcyclohexano-18-crown-6 solutions in 1-octanol were studied by ESR spectroscopy. Hydroxyalkyl CH 3 (CH 2 ) 6 C circle HOH and interior-type alkyl R 1 C circle HR 2 OH radicals were found to be main paramagnetic products stabilized in 1-octanol irradiated at 77 K. In addition to abovementioned radicals, macrocyclic -O-CH 2 -C circle H- and acyclic -C circle H-C(H)=O radicals produced from crown ether were identified in irradiated 1.0 M DtBuCH18C6 solution in octanol. No deviation in radiation-chemical yield of the stabilized acyclic radicals from the value expected in accord with 'additive' rule was observed in the latter case. It was supposed that macrocycle cleavage in DtBuCH18C6 occurred at early stages of radiolysis rather than in secondary radical reactions between products of 1-octanol radiolysis and crown ether. Meanwhile, alkyl radicals formed from 1-octanol can react with crown ether, resulting in formation of macrocyclic products of radiolysis. (orig.)

  18. Radical intermediates of low temperature radiolysis of di-tert-butylcyclohexano-18-crown-6/1-octanol extractant

    Energy Technology Data Exchange (ETDEWEB)

    Zakurdaeva, O.A.; Nesterov, S.V. [Russian Academy of Sciences, Moscow (Russian Federation). Enikolopov Institute of Synthetic Polymer Materials; Moscow State Univ. (Russian Federation). Dept. of Chemistry; Feldman, V.I. [Moscow State Univ. (Russian Federation). Dept. of Chemistry

    2013-03-01

    Intermediates of low temperature (77 K) X-rays radiolysis of 1-octanol and di-tert-butylcyclohexano-18-crown-6 solutions in 1-octanol were studied by ESR spectroscopy. Hydroxyalkyl CH{sub 3}(CH{sub 2}){sub 6}C {sup circle} HOH and interior-type alkyl R{sub 1}C {sup circle} HR{sub 2}OH radicals were found to be main paramagnetic products stabilized in 1-octanol irradiated at 77 K. In addition to abovementioned radicals, macrocyclic -O-CH{sub 2}-C {sup circle} H- and acyclic -C {sup circle} H-C(H)=O radicals produced from crown ether were identified in irradiated 1.0 M DtBuCH18C6 solution in octanol. No deviation in radiation-chemical yield of the stabilized acyclic radicals from the value expected in accord with 'additive' rule was observed in the latter case. It was supposed that macrocycle cleavage in DtBuCH18C6 occurred at early stages of radiolysis rather than in secondary radical reactions between products of 1-octanol radiolysis and crown ether. Meanwhile, alkyl radicals formed from 1-octanol can react with crown ether, resulting in formation of macrocyclic products of radiolysis. (orig.)

  19. Alkylation of Zwitterionic Thiooxalic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Manfred Michalik

    2001-05-01

    Full Text Available The new S-alkyl thiooxal-1-hydrazono-2-amidrazonium halides 2-4 were synthesized by reaction of the corresponding zwitterionic thiooxalic acid derivatives 1 with alkyl halides in methanol. The structures of compounds 4b and 4d were proven by X-ray structural analysis. Both compounds form an interesting intermolecular network of hydrogen bonds in the solid state.

  20. Mechanochemical N-alkylation of imides

    Directory of Open Access Journals (Sweden)

    Anamarija Briš

    2017-08-01

    Full Text Available The mechanochemical N-alkylation of imide derivatives was studied. Reactions under solvent-free conditions in a ball mill gave good yields and could be put in place of the classical solution conditions. The method is general and can be applied to various imides and alkyl halides. Phthalimides prepared under ball milling conditions were used in a mechanochemical Gabriel synthesis of amines by their reaction with 1,2-diaminoethane.

  1. Determination of residual acetone and acetone related impurities in drug product intermediates prepared as Spray Dried Dispersions (SDD) using gas chromatography with headspace autosampling (GCHS).

    Science.gov (United States)

    Quirk, Emma; Doggett, Adrian; Bretnall, Alison

    2014-08-05

    Spray Dried Dispersions (SDD) are uniform mixtures of a specific ratio of amorphous active pharmaceutical ingredient (API) and polymer prepared via a spray drying process. Volatile solvents are employed during spray drying to facilitate the formation of the SDD material. Following manufacture, analytical methodology is required to determine residual levels of the spray drying solvent and its associated impurities. Due to the high level of polymer in the SDD samples, direct liquid injection with Gas Chromatography (GC) is not a viable option for analysis. This work describes the development and validation of an analytical approach to determine residual levels of acetone and acetone related impurities, mesityl oxide (MO) and diacetone alcohol (DAA), in drug product intermediates prepared as SDDs using GC with headspace (HS) autosampling. The method development for these analytes presented a number of analytical challenges which had to be overcome before the levels of the volatiles of interest could be accurately quantified. GCHS could be used after two critical factors were implemented; (1) calculation and application of conversion factors to 'correct' for the reactions occurring between acetone, MO and DAA during generation of the headspace volume for analysis, and the addition of an equivalent amount of polymer into all reference solutions used for quantitation to ensure comparability between the headspace volumes generated for both samples and external standards. This work describes the method development and optimisation of the standard preparation, the headspace autosampler operating parameters and the chromatographic conditions, together with a summary of the validation of the methodology. The approach has been demonstrated to be robust and suitable to accurately determine levels of acetone, MO and DAA in SDD materials over the linear concentration range 0.008-0.4μL/mL, with minimum quantitation limits of 20ppm for acetone and MO, and 80ppm for DAA. Copyright

  2. Formulation development and manufacturing of a gastrin/CCK-2 receptor targeting peptide as an intermediate drug product for a clinical imaging study.

    Science.gov (United States)

    Sosabowski, Jane K; Lee, Myrto; Dekker, Bronwen A; Simmons, Ben P; Singh, Surjeet; Beresford, Hayden; Hagan, Susan A; McKenzie, Andrew J; Mather, Stephen J; Watson, Susan A

    2007-06-01

    A DOTA-gastrin analogue (APH070) which, when labelled with (111)In, has high affinity for the gastrin/CCK-2 receptor (3nM) and low tumour to kidney ratio in animal models, has been formulated and manufactured for a clinical study. Oxidation of the peptide methionine residue greatly reduces receptor affinity, therefore development work focused on producing a stable intermediate drug product (iDP) whilst ensuring that the formulation, container, closure and manufacturing process did not inhibit the extremely sensitive radiolabelling reaction (itself a source of oxidation). Stress testing revealed that APH070 was stable at 2-8 degrees C at pH 6-9. Addition of an antioxidant (monothioglycerol) to the peptide formulation reduced stability when compared to buffer alone. Use of FluroTec (4023/50) stoppers (rather than FluroTec Plus (4110/40)) increased both the stability and radiolabelling efficiency of APH070. Long term stability (6 months) of the final formulation (1mg/ml APH070 in 0.01 M pH 7.2 phosphate buffer) stored at 5 degrees C in type I glass vials with FluroTec (4023/50) stoppers was 98.6+/-0.2% and 98.4+/-0.1% for upright and inverted samples, respectively. Clinical scale radiolabelling of the final formulation routinely achieves the specification of >85% (111)In-APH070 (unoxidised) stable for up to 2h after dilution with 0.9% w/v saline solution. Specific uptake of the radiopharmaceutical in CCK-2R-expressing AR42J tumours in nude mice has been demonstrated.

  3. N-Alkylation by Hydrogen Autotransfer Reactions.

    Science.gov (United States)

    Ma, Xiantao; Su, Chenliang; Xu, Qing

    2016-06-01

    Owing to the importance of amine/amide derivatives in all fields of chemistry, and also the green and environmentally benign features of using alcohols as alkylating reagents, the relatively high atom economic dehydrative N-alkylation reactions of amines/amides with alcohols through hydrogen autotransfer processes have received much attention and have developed rapidly in recent decades. Various efficient homogeneous and heterogeneous transition metal catalysts, nano materials, electrochemical methods, biomimetic methods, asymmetric N-alkylation reactions, aerobic oxidative methods, and even certain transition metal-free, catalyst-free, or autocatalyzed methods, have also been developed in recent years. With a brief introduction to the background and developments in this area of research, this chapter focuses mainly on recent progress and technical and conceptual advances contributing to the development of this research in the last decade. In addition to mainstream research on homogeneous and heterogeneous transition metal-catalyzed reactions, possible mechanistic routes for hydrogen transfer and alcohol activation, which are key processes in N-alkylation reactions but seldom discussed in the past, the recent reports on computational mechanistic studies of the N-alkylation reactions, and the newly emerged N-alkylation methods based on novel alcohol activation protocols such as air-promoted reactions and transition metal-free methods, are also reviewed in this chapter. Problems and bottlenecks that remained to be solved in the field, and promising new research that deserves greater future attention and effort, are also reviewed and discussed.

  4. Access to Alkyl-Substituted Lactone via Photoredox-Catalyzed Alkylation/Lactonization of Unsaturated Carboxylic Acids.

    Science.gov (United States)

    Sha, Wanxing; Ni, Shengyang; Han, Jianlin; Pan, Yi

    2017-11-03

    An efficient photoredox-catalyzed alkylation/lactonization reaction of unsaturated carboxylic acids by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. Varieties of redox-active esters derived from aliphatic carboxylic acids were proved viable in this method, affording alkyl substituted lactones in moderate to good yields. This redox-neutral procedure features mild conditions and operational simplicity, which provides a new strategy for the synthesis of alkyl substituted lactones.

  5. Reaction rates of glutathione and ascorbate with alkyl radicals are too slow for protection against protein peroxidation in vivo.

    Science.gov (United States)

    Nauser, Thomas; Gebicki, Janusz M

    2017-11-01

    Reaction kinetics of amino acid and peptide alkyl radicals with GSH and ascorbate, the two most abundant endogenous antioxidants, were investigated by pulse radiolysis. Rate constants in the order of 10 6  M -1 s -1 were found. Alkyl radicals react at almost diffusion controlled rates and irreversibly with oxygen to form peroxyl radicals, and competition with this reaction is the benchmark for efficient repair in vivo. We consider repair of protein radicals and assume comparable rate constants for the reactions of GSH/ascorbate with peptide alkyl radicals and with alkyl radicals on a protein surface. Given physiological concentrations of oxygen, GSH and ascorbate, protein peroxyl radicals will always be a major product of protein alkyl radicals in vivo. Therefore, if they are formed by oxidative stress, protein alkyl radicals are a probable cause for biological damage. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Hydrogen-Transfer-Mediated Direct β-Alkylation of Aryl-1,8-naphthyridines with Alcohols under Transition Metal Catalyst Free Conditions.

    Science.gov (United States)

    Xiong, Biao; Zhang, Shudi; Jiang, Huanfeng; Zhang, Min

    2016-02-19

    By employing abundant and sustainable alcohols as the alkylating reagents, a new and direct alkylation method has been demonstrated. This method enables the selective alkylation of the less substituted pyridyl ring at the β-site of aryl-1,8-naphthyridines, affording the desired products in moderate to excellent yields upon isolation. The method proceeds under transition-metal-free conditions in an atom- and step-economic fashion and liberates water as the sole byproduct. Mechanistic investigations suggest the reaction undergoes a hydrogen-transfer-mediated alkylation mode.

  7. Molecular design of sequence specific DNA alkylating agents.

    Science.gov (United States)

    Minoshima, Masafumi; Bando, Toshikazu; Shinohara, Ken-ichi; Sugiyama, Hiroshi

    2009-01-01

    Sequence-specific DNA alkylating agents have great interest for novel approach to cancer chemotherapy. We designed the conjugates between pyrrole (Py)-imidazole (Im) polyamides and DNA alkylating chlorambucil moiety possessing at different positions. The sequence-specific DNA alkylation by conjugates was investigated by using high-resolution denaturing polyacrylamide gel electrophoresis (PAGE). The results showed that polyamide chlorambucil conjugates alkylate DNA at flanking adenines in recognition sequences of Py-Im polyamides, however, the reactivities and alkylation sites were influenced by the positions of conjugation. In addition, we synthesized conjugate between Py-Im polyamide and another alkylating agent, 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI). DNA alkylation reactivies by both alkylating polyamides were almost comparable. In contrast, cytotoxicities against cell lines differed greatly. These comparative studies would promote development of appropriate sequence-specific DNA alkylating polyamides against specific cancer cells.

  8. The scarlet letter of alkylation: a mini review of selective alkylating agents.

    Science.gov (United States)

    Oronsky, Bryan T; Reid, Tony; Knox, Susan J; Scicinski, Jan J

    2012-08-01

    If there were a stigma scale for chemotherapy, alkylating agents would be ranked at the top of the list. The chemical term alkylation is associated with nonselective toxicity, an association that dates back to the use of nitrogen mustards during World War I as chemical warfare agents. That this stigma persists and extends to compounds that, through selectivity, attempt to "tame" the indiscriminate destructive potential of alkylation is the subject of this review. Selective alkylation, as it is referred to herein, constitutes an extremely nascent and dynamic field in oncology. The pharmacodynamic response to this selective strategy depends on a delicate kinetic balance between specificity and the rate and extent of binding. Three representative compounds are presented: RRx-001, 3-bromopyruvate, and TH-302. The main impetus for the development of these compounds has been the avoidance of the serious complications of traditional alkylating agents; therefore, it is the thesis of this review that they should not experience stigma by association.

  9. Alkylation of isobutane with light olefins: Yields of alkylates for different olefins

    Energy Technology Data Exchange (ETDEWEB)

    Albright, L.F. [Purdue Univ., West Lafayette, IN (United States); Kranz, K.E.; Masters, K.R. [STRATCO, Inc., Leawood, KS (United States)

    1993-12-01

    For alkylation of isobutane with C{sub 3}-C{sub 5} olefins using sulfuric acid as the catalyst, the yields of alkylates with different olefins are compared as the operating conditions are changed. The results of recent pilot plant experiments with propylene, C{sub 4} olefins, and C{sub 5} olefins permit such comparisons. The yields expressed as weight of alkylate produced per 100 wt of olefin consumed varied from about 201:100 to 220:100. Weight ratios of the isobutane consumed per olefin consumed vary from about 101:100 to 120:100. differences of yield values are explained by the changes in the overall chemistry. The procedure employed to calculate yields with good accuracy is based on the analysis of the alkylate and the amount of conjunct polymers produced. Based on literature data, yields are also reported for alkylations using HF as the catalyst.

  10. Safety Assessment of Amino Acid Alkyl Amides as Used in Cosmetics.

    Science.gov (United States)

    Burnett, Christina L; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the product use, formulation, and safety data of 115 amino acid alkyl amides, which function as skin and hair conditioning agents and as surfactants-cleansing agents in personal care products. Safety test data on dermal irritation and sensitization for the ingredients with the highest use concentrations, lauroyl lysine and sodium lauroyl glutamate, were reviewed and determined to adequately support the safe use of the ingredients in this report. The Panel concluded that amino acid alkyl amides are safe in the present practices of use and concentration in cosmetics, when formulated to be nonirritating.

  11. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

  12. High yield silicon carbide from alkylated or arylated pre-ceramic polymer

    International Nuclear Information System (INIS)

    Baney, R.H.; Gaul, J.H.

    1982-01-01

    Alkylated or arylated methylpolysilanes which exhibit ease of handling and are used to obtain silicon carbide ceramic materials in high yields contain 0 to 60 mole percent (CH 3 ) 2 Si double bond units and 40 to 100 mole percent CH 3 Si triple bond units, wherein there is also bonded to the silicon atoms other silicon atoms and additional alkyl radicals of 1 to 4 carbon atoms or phenyl. They may be prepared by reaction of a Grignard reagent RMgX, where X is halogen and R is Csub(1-4)-alkyl or phenyl, with a starting material which is a solid at 25 0 C, and is identical to the product except that the remaining bonds on the silicon atoms are attached to another silicon atom, or a chlorine or a bromine atom. Ceramics result from heating the polysilane products to 1200 0 C, optionally with fillers. (author)

  13. γ-radiolysis of dialkyl, alkyl-aryl and diaryl sulphones

    International Nuclear Information System (INIS)

    Bowmer, T.N.; O'Donnell, J.H.

    1981-01-01

    Dialkyl sulphones, RSO 2 R, have been considered as model compounds for the radiolysis of poly(olefin sulphone)s. They show preferential C-S scission and SO 2 elimination, attributable to the relatively low strengths of these bonds. Combination of the alkyl radicals, which are produced singly or in pairs according to whether one or two C-S scissions occur in one molecule, competes with hydrogen abstraction from sulphone molecules. The latter is favoured for single C-S scissions and as the size of the radical increases and hence its mobility decreases. An important degradation reaction in radiolysis is considered to be ionization to form the cation radical of the dialkyl sulphone, followed by a single C-S scission to produce the alkyl radical and the complementary alkyl sulphonyl cation, which may undergo scission of the remaining C-S bond to produce SO 2 . GC/MS studies of the volatile products from dimethyl sulphone have shown that radiolysis results in a complexity of fragmentation and combination reactions, involving scission of most bonds in the molecule. The variety of products has been confirmed using CD 3 SO 2 CD 3 . Radiation protection by aromatic substituents has been demonstrated and branched alkyls have been shown to give higher yields of alkanes and SO 2 than linear alkyls. (author)

  14. Mitsunobu mischief: Neighbor-directed histidine N(π)–alkylation provides access to peptides containing selectively functionalized imidazolium heterocycles

    Science.gov (United States)

    Qian, Wen-Jian

    2015-01-01

    There are few methodologies that yield peptides containing His residues with selective N(π), N(π)-bis-alkylated imidazole rings. We have found that, under certain conditions, on-resin Mitsunobu coupling of alcohols with peptides having a N(π)-alkylated His residue results in selective and high-yield alkylation of the imidazole N(π) nitrogen. The reaction requires the presence of a proximal phosphoric, carboxylic or sulfonic acid, and proceeds through an apparent intramolecular mechanism involving Mitsunobu intermediates. These transformations have particular application to phosphopeptides, where “charge masking” of one phosphoryl anionic charge by the cationic histidine imidazolium ion is now possible. This chemistry opens selective access to peptides containing differentially functionalized imidazolium heterocycles, which provide access to new classes of peptides and peptide mimetics. PMID:25739367

  15. Outlook for the U.S. alkylation industry

    International Nuclear Information System (INIS)

    Felten, J.R.; Bradshaw, T.; McCarthy, K.

    1994-01-01

    Alkylation has long been recognized in the refining industry as one of the best options to convert refinery olefins into valuable, clean, high octane blending components. In fact, refinery alkylation is a preferred source of blending stocks for reformulated gasoline. However, the hydrofluoric acid (HF) alkylation process and, to a lesser extent, the sulfuric acid (SA) process have come under increasing pressure in the US due to safety and environmental concerns. This paper examines the current outlook for the US alkylation industry including: key trends and driving forces in the industry, the impact of environmental issues on both HF and SA alkylation, US alkylation supply/demand forecast including the outlook for oxygenates, how US refines will respond to the increased demand and restricted supply for alkylates, and the outlook for new solid acid alkylation (SAC) technology

  16. Mechanisms of resistance to alkylating agents

    OpenAIRE

    Damia, G.; D‘Incalci, M.

    1998-01-01

    Alkylating agents are the most widely used anticancer drugs whose main target is the DNA, although how exactly the DNA lesions cause cell death is still not clear. The emergence of resistance to this class of drugs as well as to other antitumor agents is one of the major causes of failure of cancer treatment. This paper reviews some of the best characterized mechanisms of resistance to alkylating agents. Pre- and post-target mechanisms are recognized, the former able to limit the formation of...

  17. Facile alkylation of 4-nitrobenzotriazole and its platelet aggregation inhibitory activity.

    Science.gov (United States)

    Singh, Dhandeep; Silakari, Om

    2017-10-15

    We explored the facile alkylation of 4-nitrobenzotriazole under basic conditions and the synthesized derivatives were tested for their potential ADP induced platelet aggregation inhibition activity in comparison with standard drug ticagrelor (selective P2Y12 inhibitor). The nitro group at 4-position is highly activating toward alkylation reactions (under strong basic conditions) and resulted in formation of degradation product like 3-nitrobenzene-1,2-diamine which make isolation of alkyl products very difficult. We optimized the reaction under mild basic condition (potassium carbonate and DMF) which is devoid of any degradation product. This is perhaps the first report of 4-nitrobenzotriazole derivatives possessing platelet aggregation inhibitory activity. Generally activity increases with increase in length of alkyl chain and 1-alkyl positional isomers were found to be more potent than 2-alkyl isomers. The benzoyl derivative was found to be the most potent [compound 22; (4-Nitro-1H-benzotriazol-1-yl)(phenyl)methanone; IC 50 =0.65±0.10mM] which may be attributed to electronegative oxygen atom and aromatic ring. Benzyl derivatives [compound 20; 1-Benzyl-4-nitro-1H-benzotriazole; IC 50 =0.81±0.08mM, compound 21; 2-Benzyl-4-nitro-2H-benzotriazole; IC 50 =0.82±0.19mM] and sulfonyl derivative [compound 23; 1-[(4-Methylphenyl)sulfonyl]-4-nitro-1H-benzotriazole; IC 50 =0.82±0.19mM] are also found to be highly active. Furthermore, all compounds possess P2Y12 binding affinity as confirmed by VASP/P2Y12 phosphorylation assay. Copyright © 2017. Published by Elsevier Ltd.

  18. Oxidative Umpolung α‐Alkylation of Ketones

    DEFF Research Database (Denmark)

    Shneider, O. Svetlana; Pisarevsky, Evgeni; Fristrup, Peter

    2015-01-01

    We disclose a hypervalent iodine mediated α-alkylative umpolung reaction of carbonyl compounds with dialkylzinc as the alkyl source. The reaction is applicable to all common classes of ketones including 1,3-dicarbonyl compounds and regular ketones via their lithium enolates. The α-alkylated...

  19. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl silane...

  20. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

  1. IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    Science.gov (United States)

    A detailed study of the alkylation of isobutane with 2-butene in ionic liquid media has been conducted using 1-alkyl-3-methylimidazolium halides?aluminum chloride encompassing various alkyl groups (butyl-, hexyl-, and octyl-) and halides (Cl, Br, and I) on its cations and anions,...

  2. Reaction Mechanism and Deactivation Pathways in Zeolite catalyzed Isobutane/2-Butene Alkylation

    OpenAIRE

    Feller, Andreas

    2007-01-01

    In this thesis, the isobutane/2-butene alkylation was studied on lanthanum-exchanged zeolite X in a CSTR-type slurry reactor. Catalysts with a high concentration of strong Brønsted acid sites and a high Brønsted to Lewis acid site ratio exhibited higher active catalytic lifetimes than samples with lower ratios. Isobutane self-alkylation activity was also increasing with increasing Brønsted/Lewis ratio. The integral productivity of the catalysts was found to be independent of the butene space ...

  3. Insertion of molecular oxygen into a palladium(II) methyl bond: a radical chain mechanism involving palladium(III) intermediates.

    Science.gov (United States)

    Boisvert, Luc; Denney, Melanie C; Hanson, Susan Kloek; Goldberg, Karen I

    2009-11-04

    The reaction of (bipy)PdMe(2) (1) (bipy = 2,2'-bipyridine) with molecular oxygen results in the formation of the palladium(II) methylperoxide complex (bipy)PdMe(OOMe) (2). The identity of the product 2 has been confirmed by independent synthesis. Results of kinetic studies of this unprecedented oxygen insertion reaction into a palladium alkyl bond support the involvement of a radical chain mechanism. Reproducible rates, attained in the presence of the radical initiator 2,2'-azobis(2-methylpropionitrile) (AIBN), reveal that the reaction is overall first-order (one-half-order in both [1] and [AIBN], and zero-order in [O(2)]). The unusual rate law (half-order in [1]) implies that the reaction proceeds by a mechanism that differs significantly from those for organic autoxidations and for the recently reported examples of insertion of O(2) into Pd(II) hydride bonds. The mechanism for the autoxidation of 1 is more closely related to that found for the autoxidation of main group and early transition metal alkyl complexes. Notably, the chain propagation is proposed to proceed via a stepwise associative homolytic substitution at the Pd center of 1 with formation of a pentacoordinate Pd(III) intermediate.

  4. Selective Alkylation of C-Rich Bulge Motifs in Nucleic Acids by Quinone Methide Derivatives.

    Science.gov (United States)

    Lönnberg, Tuomas; Hutchinson, Mark; Rokita, Steven

    2015-09-07

    A quinone methide precursor featuring a bis-cyclen anchoring moiety has been synthesized and its capacity to alkylate oligonucleotide targets quantified in the presence and absence of divalent metal ions (Zn(2+) , Ni(2+) and Cd(2+) ). The oligonucleotides were designed for testing the sequence and secondary structure specificity of the reaction. Gel electrophoretic analysis revealed predominant alkylation of C-rich bulges, regardless of the presence of divalent metal ions or even the bis-cyclen anchor. This C-selectivity appears to be an intrinsic property of the quinone methide electrophile as reflected by its reaction with an equimolar mixture of the 2'-deoxynucleosides. Only dA-N1 and dC-N3 alkylation products were detected initially and only the dC adduct persisted for detection under conditions of the gel electrophoretic analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

    Directory of Open Access Journals (Sweden)

    Daily Rodríguez-Padrón

    2017-09-01

    Full Text Available Polysaccharides from natural sources and iron precursors were applied to develop new bio-nanocomposites by mechanochemical milling processes. The proposed methodology was demonstrated to be advantageous in comparison with other protocols for the synthesis of iron oxide based nanostructures. Additionally, mechanochemistry has enormous potential from an environmental point-of-view since it is able to reduce solvent issues in chemical syntheses. The catalytic activity of the obtained nanocatalysts was investigated in both the oxidation of benzyl alcohol to benzaldehyde and in the alkylation of toluene with benzyl chloride. The microwave-assisted oxidation of benzyl alcohol reached 45% conversion after 10 min. The conversion of the alkylation of toluene in both microwave-assisted and conventional heating methods was higher than 99% after 3 min and 30 min, respectively. The transformation of benzyl alcohol and toluene into valuable product in both the oxidation and alkylation reaction reveals a potential method for the valorization of lignocellulosic biomass.

  6. Isobutane/butene alkylation on solid catalysts. Where do we stand?

    Energy Technology Data Exchange (ETDEWEB)

    Weitkamp, J.; Traa, Y. [Institute of Chemical Technology I, University of Stuttgart, D-70550 Stuttgart (Germany)

    1999-02-24

    Liquid-phase processes with concentrated sulfuric acid or hydrogen fluoride as catalysts are currently being used in petroleum refining for the manufacture of alkylation gasoline from isobutane and butenes. While the product, i.e., alkylate, is a most valuable gasoline component, the existing processes for its manufacture are less satisfactory. Replacement of the liquid catalysts by a solid acid is an important target of modern research. In the past two decades, a large number of solid acids have been scrutinized, and at least four developments were driven till the pilot plant stage. In this paper, an attempt is made to rationalize, on a mechanistic basis, the selectivity loss almost always encountered with solid acids after relatively short times-on-stream. Suggestions are made concerning a more target-oriented research on isobutane/alkene alkylation in the future

  7. Quantitative estimation of the extent of alkylation of DNA following treatment of mammalian cells with non-radioactive alkylating agents

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, R.D. (Univ. of Tennessee, Oak Ridge); Regan, J.D.

    1981-01-01

    Alkaline sucrose sedimentation has been used to quantitate phosphotriester formation following treatment of human cells with the monofunctional alkylating agents methyl and ethyl methanesulfonate. These persistent alkaline-labile lesions are not repaired during short-term culture conditions and thus serve as a useful and precise index of the total alkylation of the DNA.Estimates of alkylation by this procedure compare favorably with direct estimates by use of labeled alkylating agents.

  8. Williamson alkylation approach to the synthesis of poly(alkyl vinyl ether) copolymers

    International Nuclear Information System (INIS)

    Markova, D.; Christova, D.; Velichkova, R.

    2008-01-01

    A method for synthesis of poly(alkyl vinyl ether-co-vinyl alcohol) copolymers was developed based on the Williamson's alkylation of poly(vinyl acetate) (PVAc) with alkyl iodides. The influence of the alkylating agent and the reaction conditions on the efficiency of the modification reaction was investigated. The copolymers obtained were characterized by means of 1 H NMR and GPC. It was proved that by applying the proposed method copolymers of different composition and properties containing methyl vinyl ether, ethyl vinyl ether as well as n-butyl vinyl ether units could be prepared. Poly(methyl vinyl ether-co-vinyl alcohol)s of high degree of methylation exhibit sharp temperature response at 38-39 deg C in aqueous solution typical of the so-called smart polymers. (authors)

  9. Determinants of serum levels of perfluorinated alkyl acids in Danish pregnant women

    DEFF Research Database (Denmark)

    Bjerregaard-Olesen, Christian; Bach, Cathrine C; Long, Manhai

    2016-01-01

    Humans are exposed to perfluorinated alkyl acids (PFAAs) from food, drinking water, air, dust, and consumer products. PFAAs are persistent and bio-accumulative. In the present study, we aimed to establish how the serum levels of PFAAs differ according to age, pre-pregnancy body mass index (BMI...

  10. Cu-Catalyzed Asymmetric Allylic Alkylation of Phosphonates and Phosphine Oxides with Grignard Reagents

    NARCIS (Netherlands)

    Hornillos, Valentin; Perez, Manuel; Fananas-Mastral, Martin; Feringa, Ben L.

    An efficient and highly enantioselective copper-catalyzed allylic alkylation of phosphonates and phosphine oxides with Grignard reagents and Taniaphos or phosphoramidites as chiral ligands is reported. Transformation of these products leads to a variety of new phosphorus-containing chiral

  11. Alkylations and hydroxymethylations of pyrazines via green Minisci-type reactions.

    Science.gov (United States)

    Bohman, Bjorn; Berntsson, Benjamin; Dixon, Ruby C M; Stewart, Craig D; Barrow, Russell A

    2014-06-06

    A new general methodology utilizing Minisci-type chemistry has been developed that cleanly and efficiently prepares alkyl- and (hydroxymethyl)pyrazines. The new methods eliminate toxic catalysts and halogenated solvents, providing a greatly improved route to these natural products which are prevalent in many natural systems as bacterial volatiles, plant volatiles, and insect pheromones.

  12. New Route to Synthesize Surface Organometallic Complexes (SOMC): An Approach by Alkylating Halogenated Surface Organometallic Fragments

    KAUST Repository

    Hamieh, Ali Imad

    2017-02-01

    The aim of this thesis is to explore new simpler and efficient routes for the preparation of surface organometallic complexes (SOMC) for the transformation of small organic molecules to valuable products. The key element in this new route relies on surface alkylation of various halogenated surface coordination complexes or organometallic fragments (SOMF).

  13. An efficient and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles via ...

    Indian Academy of Sciences (India)

    L Raju Chowhan

    Abstract. A robust and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles from isatins is described. This method introduces an ecofriendly, un-activated Zn dust, solid NH4Cl and substrates under aqueous conditions, which has produced the product in moderate to good yields. Without using column chromatography, majority ...

  14. Hydride transfer versus deprotonation kinetics in the isobutane−propene alkylation reaction : A computational study

    NARCIS (Netherlands)

    Liu, Chong; Van Santen, Rutger A.; Poursaeidesfahani, A.; Vlugt, T.J.H.; Pidko, Evgeny A.; Hensen, Emiel J M

    2017-01-01

    The alkylation of isobutane with light alkenes plays an essential role in modern petrochemical processes for the production of high-octane gasoline. In this study we have employed periodic DFT calculations combined with microkinetic simulations to investigate the complex reaction mechanism of

  15. the influence of acidity of zeolite H-BEA catalyzed isobutane/n-butene alkylation

    NARCIS (Netherlands)

    Nivarthy, G.S.; Seshan, Kulathuiyer; Lercher, J.A.

    1998-01-01

    The influence of the concentration of acid sites for isobutane/n-butene alkylation on zeolite BEA with varying degrees of Na+ ion exchange is reported. All catalysts studied showed complete n-butene conversion over a significant time-on-stream. Isooctanes were the dominating products over H-BEA,

  16. Thermodynamic calculation of simultaneous reactions of n-butane isomerization and isobutane alkylation with ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Batyrshin, N.N.; Beresneva, L.D.; Sidorov, V.A.

    1981-08-01

    Industrial production of ethylene alkylate has gained further development in connection with worldwide ecological problems and the planned changeover of automobile transport to unleaded gasolines, but the scale of production is still substantially less than that of sulfuric acid or hydrogen fluoride alkylates. This is due both to the instability of market prices for ethylene and the shortage of isobutane - a raw material for these large-tonnage production processes and for the synthetic rubber industry. The latter difficulty can be overcome by combining processes of isomerization of n-butane and alkylation of the resultant isobutane with ethylene in a single reaction unit. The possibility of combining these reactions using AlCl/sub 3/-based catalysts has been pointed out previously but in the literature there are no theoretical developments of technology or thermodynamic substantiation of a combined process. We have made a thermodynamic calculation of the consecutive (series-parallel) reactions of isomerization and alkylation with the goal of determining suitable technological conditions for carrying them out simultaneously and establishing the expected equilibrium yields of target products and the compositions of the reaction mixture.

  17. elementary mechanistic steps and the influence of process variables in isobutane alkylation over H-BEA

    NARCIS (Netherlands)

    Nivarthy, G.S.; He, Y.; Seshan, Kulathuiyer; Lercher, J.A.

    1998-01-01

    Liquid phase conversion of n-butene in excess iso-butane was investigated over zeolite BEA as catalyst in a continuously operated slurry reactor. Single and multiple alkylation and cracking were the main reaction pathways. Only saturated products were observed indicating that hydride transfer

  18. Spurious cooperativity in alkylated succinic acids

    Science.gov (United States)

    Ben-Naim, A.

    1998-03-01

    The proton-proton correlation, as measured by the ratio between the second and the first dissociation constants of dibasic acid, is sometimes very large and far beyond what could be explained by electrostatic theories. We propose a novel interpretation of this phenomenon based on the idea of spurious cooperativity. The general theoretical framework underlying the onset of spurious cooperativity is developed first. The basic result is that whenever a binding (or dissociating) two-site (or more) system splits into a mixture of noninterconverting isomers the binding isotherm (or the titration curve) behaves as if it is more negatively cooperative compared with the genuine cooperativities of the individual isomer. The theory is applied to a specific system of α-α' dialkyl succinic acid. It is known that the Meso form of these alkylated derivatives show a normal correlation of the same order of magnitude as in succinic acid. On the other hand, the Racemic form of these alkylated derivatives shows anomalous strong negative correlations when the alkyl groups become large (e.g., isopropyl and tert butyl). It is shown that the theory of spurious cooperativity can explain the different behavior of the Racemic and the Meso forms, as well as the onset of anomalous strong negative correlations when the alkyl groups become large.

  19. Biodesulfurization of dibenzothiophene and its alkylated derivatives ...

    African Journals Online (AJOL)

    RIPI-S81 is a new dibenzothiophene (DBT)-desulfurizing bacterium, which was isolated by Research Institute of Petroleum Industry in Iran. Resting cells and growing cells of RIPI-S81 was able to convert alkylated dibenzothiophenes (Cx DBTs) to hydroxybiphenyls such that they were almost stoichiometrically accumulated ...

  20. Poly(ethyleneoxide) functionalization through alkylation

    Science.gov (United States)

    Sivanandan, Kulandaivelu; Eitouni, Hany Basam; Li, Yan; Pratt, Russell Clayton

    2015-04-21

    A new and efficient method of functionalizing high molecular weight polymers through alkylation using a metal amide base is described. This novel procedure can also be used to synthesize polymer-based macro-initiators containing radical initiating groups at the chain-ends for synthesis of block copolymers.

  1. Catalytic Asymmetric Alkylation of Aryl Heteroaryl Ketones

    NARCIS (Netherlands)

    Ortiz, Pablo; Harutyunyan, Syuzanna; del Hoyo, Ana

    Tertiary diarylmethanols are highly bioactive structural motifs. A new strategy to access chiral tertiary diarylmethanols through copper-catalyzed direct alkylation of (di)(hetero)aryl ketones by using Grignard reagents was developed. The low reactivity and the similarity of the enantiotopic faces

  2. Palladium Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Engelin, Casper Junker; Fristrup, Peter

    2011-01-01

    an acetate ion coordinated to Pd. Several of the reported systems rely on benzoquinone for re-oxidation of the active catalyst. The scope for nucleophilic addition in allylic C-H alkylation is currently limited, due to demands on pKa of the nucleophile. This limitation could be due to the pH dependence...

  3. Electrochemical synthesis of alkyl nitroaromatic compounds.

    Science.gov (United States)

    Gallardo, Iluminada; Guirado, Gonzalo; Marquet, Jordi

    2003-01-24

    Alkyl nitroaromatic compounds were readily prepared via nucleophilic aromatic substitution for hydrogen or a heteroatom by electrochemical oxidation of the sigma-complex. Butyllithium and butylmagnesium chloride were used as nucleophiles, and several nitrocompounds were tested to explore the possibilities of the NASH and NASX reactions promoted electrochemically.

  4. Palladium catalysed asymmetric alkylation of benzophenone Schiff ...

    Indian Academy of Sciences (India)

    transfer catalysts for asym- metric alkylation of achiral Schiff base esters. Trans. Met. Chem. 35 249. (doi:10.1007/s11243-010-9416-4). 29. Wilkes J S 2002 A short history of ionic liquids from molten salts to neoteric solvents. Green Chem. 4 73. 30.

  5. Recent developments in isobutane/olefin alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Lercher, J.A.; Feller, A. [Inst. fuer Technische Chemie, Technische Univ. Muenchen (Germany)

    2002-07-01

    The isobutane/alkene alkylation is reviewed with respect to recent process developments based on liquid and solid acid catalysts. A brief overview about the established processes is given followed by the description of new processes based on solid acids under development. (orig.)

  6. Mechanisms of action of quinone-containing alkylating agents: DNA alkylation by aziridinylquinones.

    Science.gov (United States)

    Hargreaves, R H; Hartley, J A; Butler, J

    2000-11-01

    Aziridinyl quinones can be activated by cellular reductases eg. DT-diaphorase and cytochrome P450 reductase to form highly reactive DNA alkylating agents. The mechanisms by which this activation and alkylation take place are many and varied. Using clinically relevant and experimental agents this review will describe many of these mechanisms. The agents discussed are Mitomycin C, EO9 and analogues, diaziridinylbenzoquinones and the pyrrolo[1, 2-alpha]benzimidazolequinones.

  7. A Detailed Chemical Kinetic Reaction Mechanism for Oxidation of Four Small Alkyl Esters in Laminar Premixed Flames

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Westmoreland, P R; Dryer, F L; Chaos, M; Osswald, P; Kohse-Hoinghaus, K; Cool, T A; Wang, J; Yang, B; Hansen, N; Kasper, T

    2008-02-08

    A detailed chemical kinetic reaction mechanism has been developed for a group of four small alkyl ester fuels, consisting of methyl formate, methyl acetate, ethyl formate and ethyl acetate. This mechanism is validated by comparisons between computed results and recently measured intermediate species mole fractions in fuel-rich, low pressure, premixed laminar flames. The model development employs a principle of similarity of functional groups in constraining the H atom abstraction and unimolecular decomposition reactions in each of these fuels. As a result, the reaction mechanism and formalism for mechanism development are suitable for extension to larger oxygenated hydrocarbon fuels, together with an improved kinetic understanding of the structure and chemical kinetics of alkyl ester fuels that can be extended to biodiesel fuels. Variations in concentrations of intermediate species levels in these flames are traced to differences in the molecular structure of the fuel molecules.

  8. Bis(trialkylsilyl) peroxides as alkylating agents in the copper-catalyzed selective mono-N-alkylation of primary amides.

    Science.gov (United States)

    Sakamoto, Ryu; Sakurai, Shunya; Maruoka, Keiji

    2017-06-13

    The copper-catalyzed selective mono-N-alkylation of primary amides with bis(trialkylsilyl) peroxides as alkylating agents was reported. The results of a mechanistic study suggest that this reaction should proceed via a free radical process that includes the generation of alkyl radicals from bis(trialkylsilyl) peroxides.

  9. Sulfonium Salts as Alkylating Agents for Palladium-Catalyzed Direct Ortho Alkylation of Anilides and Aromatic Ureas.

    Science.gov (United States)

    Simkó, Dániel Cs; Elekes, Péter; Pázmándi, Vivien; Novák, Zoltán

    2018-02-02

    A novel method for the ortho alkylation of acetanilide and aromatic urea derivatives via C-H activation was developed. Alkyl dibenzothiophenium salts are considered to be new reagents for the palladium-catalyzed C-H activation reaction, which enables the transfer of methyl and other alkyl groups from the sulfonium salt to the aniline derivatives under mild catalytic conditions.

  10. Intermediate algebra a textworkbook

    CERN Document Server

    McKeague, Charles P

    1985-01-01

    Intermediate Algebra: A Text/Workbook, Second Edition focuses on the principles, operations, and approaches involved in intermediate algebra. The publication first takes a look at basic properties and definitions, first-degree equations and inequalities, and exponents and polynomials. Discussions focus on properties of exponents, polynomials, sums, and differences, multiplication of polynomials, inequalities involving absolute value, word problems, first-degree inequalities, real numbers, opposites, reciprocals, and absolute value, and addition and subtraction of real numbers. The text then ex

  11. Intermediate algebra & analytic geometry

    CERN Document Server

    Gondin, William R

    1967-01-01

    Intermediate Algebra & Analytic Geometry Made Simple focuses on the principles, processes, calculations, and methodologies involved in intermediate algebra and analytic geometry. The publication first offers information on linear equations in two unknowns and variables, functions, and graphs. Discussions focus on graphic interpretations, explicit and implicit functions, first quadrant graphs, variables and functions, determinate and indeterminate systems, independent and dependent equations, and defective and redundant systems. The text then examines quadratic equations in one variable, system

  12. Reactive nitrogen intermediate production and tolerance variability in different mouse strains after in vivo treatment with lipopolysaccharide from Salmonella abortus equi.

    Science.gov (United States)

    Nahrevanian, Hossein; Salmasi, Jafar Gholizadeh; Farahmand, Mahin; Aghighi, Zohreh; Assmar, Mehdi; Abolhassani, Mohsen

    2005-06-01

    Lipopolysaccharide (LPS) stimulation in animal models generates a large number of immune factors including cytokines and mediators. It also acts as a potent inducer of macrophage reactive oxygen intermediates and reactive nitrogen intermediates (RNI). RNI as stable metabolites of nitric oxide (NO) are produced by cells stimulated with LPS and cytokines. In this study, LPS from Salmonella abortus equi was investigated as an inducer of RNI in untreated controls and test groups of white Naval Medical Research Institute (NMRI) mice. Animals were humanely killed at 30, 60, 120 and 180 min after LPS injection, and plasma RNI was measured by Griess microassay. In a further experiment, host tolerance against bacterial LPS was evaluated by sequential intravenous injection of LPS concentrations of 4, 1 and 0.5 mg/kg at 24 h intervals in NMRI and with the same schedule but via subcutaneous injection in Balb/c mice. Statistical analysis of RNI values using analysis of variance test indicated that in vivo LPS stimulation induced high levels of NO in murine hosts (pRNI levels at different times after administration revealed the largest amount of RNI at 180 min after inoculation. Analysis of the time course until maximum RNI induction indicated that NMRI mice had the longest delay, suggesting a difference in tolerance of NMRI and Balb/c mice to LPS stimulation dependent on LPS concentration, dose, and route of inoculation.

  13. Embryotoxicity induced by alkylating agents. Some methodological aspects of DNA alkylation studies in murine embryos using ethylmethanesulfonate.

    Science.gov (United States)

    Platzek, T; Bochert, G; Rahm, U; Neubert, D

    1987-05-01

    Synthesis and spectroscopic analysis of some alkylated DNA purine bases are described. HPLC separation methods are developed for the determination of DNA alkylation rates in mammalian embryonic tissues. Following treatment of pregnant mice with the ethylating agent ethylmethanesulfonate (EMS), an appreciable amount of alkylation (ethylation and methylation) was found in the nuclear DNA of the embryos during organogenesis. The results are discussed in context of our thesis that a certain amount of DNA alkylation in the embryos is correlated to the teratogenic potential of alkylating agents.

  14. Reaction of lithium diethylamide with an alkyl bromide and alkyl benzenesulfonate: origins of alkylation, elimination, and sulfonation.

    Science.gov (United States)

    Gupta, Lekha; Ramírez, Antonio; Collum, David B

    2010-12-17

    A combination of NMR, kinetic, and computational methods are used to examine reactions of lithium diethylamide in tetrahydrofuran (THF) with n-dodecyl bromide and n-octyl benzenesulfonate. The alkyl bromide undergoes competitive S(N)2 substitution and E2 elimination in proportions independent of all concentrations except for a minor medium effect. Rate studies show that both reactions occur via trisolvated-monomer-based transition structures. The alkyl benzenesulfonate undergoes competitive S(N)2 substitution (minor) and N-sulfonation (major) with N-sulfonation promoted at low THF concentrations. The S(N)2 substitution is shown to proceed via a disolvated monomer suggested computationally to involve a cyclic transition structure. The dominant N-sulfonation follows a disolvated-dimer-based transition structure suggested computationally to be a bicyclo[3.1.1] form. The differing THF and lithium diethylamide orders for the two reactions explain the observed concentration-dependent chemoselectivities.

  15. Photoionization of N-Alkyl N, N', - in Organized Molecular Assemblies

    Science.gov (United States)

    Stenland, Christopher John

    The electron donors N-Alkyl N,N^ ',N^' -trimethylbenzidines (C_{rm n }TMB with n = 1 to 16) were synthesized then photoionized in rapidly frozen micellar, vesicular and reversed micellar solutions. The N-alkyl functionalization of these electron donors alters the solubilization location of C_{rm n}TMB with respect to the aqueous interface in these organized molecular assemblies. The alteration of the solubilization location affects the, relative photoyield. Electron spin resonance is used to quantify and identify the photoproduced radicals in these rapidly frozen solution. Electron spin echo modulation spectroscopy is used to monitor the distance of the cation radical of C_{rm n}TMB to the deuterated aqueous interface. In micelles, longer N-alkyl chains on C _{rm n}TMB push the benzidine moiety towards the aqueous interface. However the photoyield remains constant versus the C_{rm n}TMB alkyl chain length. The lack of a photoyield trend is interpreted in terms of the solubilization geometry which determines the paths of electron escape to form charge separated products. In vesicles, the longer the alkyl chain on C _{rm n}TMB, the deeper the benzidine moiety is located, and the lower the photoyield. The relative photoyield in bilayer vesicles depends on the proximity of the electron donor to the interface. In Aerosol dioctyl reversed micelles in isooctane, a negligible C_{rm n}TMB alkyl chain length effect is observed. Instead the water pool size, which can be manipulated by altering the mole ratio of water to surfactant, is the dominant factor which controls the net photoyield.

  16. Statistical and off-equilibrium production of fragments in heavy ion collisions at intermediate energies; Production statistique et hors-equilibre de fragments dans les collisions d`ions lourdes aux energies intermediaires

    Energy Technology Data Exchange (ETDEWEB)

    Bocage, Frederic [Lab. de Physique Corpusculaire, Caen Univ., 14 - Caen (France)

    1998-12-15

    The study of reaction products, fragments and light charged particles, emitted during heavy-ion collisions at intermediate energies has shown the dominant binary dissipative character of the reaction, which is persisting for almost all impact parameters. However, in comparison with this purely binary process, an excess of nuclear matter is observed in-between the quasi-projectile and the quasi-target. To understand the mechanisms producing such an excess, this work studies more precisely the breakup in two fragments of the quasi-projectile formed in Xe+Sn, from 25 to 50 MeV/u, and Gd+C and Gd+U at 36 MeV/u. The data were obtained during the first INDRA experiment at GANIL. The angular distributions of the two fragments show the competition between statistical fission and non-equilibrated breakup of the quasi-projectile. In the second case, the two fragments are aligned along the separation axis of the two primary partners. The comparison of the fission directions and probabilities with statistical models allows us to measure the fission time, as well as the angular momentum, temperature and size of the fissioning residue. The relative velocities are compatible with Coulomb and thermal effects in the case of statistical fission and are found much higher for the breakup of a non-equilibrated quasi-projectile, which indicates that the projectile was deformed during interaction with the target. Such deformations should be compared with dynamical calculations in order to constrain the viscosity of nuclear matter and the parameters of the nucleon-nucleon interaction, (author) 148 refs., 77 figs., 11 tabs.

  17. New insight into the spatiotemporal variability and source apportionments of C1-C4 alkyl nitrates in Hong Kong

    Science.gov (United States)

    Ling, Zhenhao; Guo, Hai; Simpson, Isobel Jane; Saunders, Sandra Maria; Lam, Sean Ho Man; Lyu, Xiaopu; Blake, Donald Ray

    2016-07-01

    C1-C4 alkyl nitrates (RONO2) were measured concurrently at a mountain site, Tai Mo Shan (TMS), and an urban site, Tsuen Wan (TW), at the base of the same mountain in Hong Kong from September to November 2010. Although the levels of parent hydrocarbons were much lower at TMS (p TMS mainly resulted from the photooxidation of the parent hydrocarbons at TW during mesoscale circulation, i.e., valley breezes, corresponding to 52-86 % of the alkyl nitrate levels at TMS. Furthermore, regional transport from the inland PRD region made significant contributions to the levels of alkyl nitrates (˜ 58-82 %) at TMS in the non-meso scenario, resulting in similar levels of alkyl nitrates observed at the two sites. The simulation of secondary formation pathways using a photochemical box model found that the reaction of alkyl peroxy radicals (RO2) with nitric oxide (NO) dominated the formation of RONO2 at both sites, and the formation of alkyl nitrates contributed negatively to O3 production, with average reduction rates of 4.1 and 4.7 pptv pptv-1 at TMS and TW, respectively.

  18. Nitric oxide donors attenuate clongenic potential in rat C6 glioma cells treated with alkylating chemotherapeutic agents.

    Science.gov (United States)

    Yang, Jir-Jei; Yin, Jiu-Haw; Yang, Ding-I

    2007-05-11

    1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) kills tumor cells via multiple actions including alkylation and carbamoylation. Previously, we have reported that formation of S-nitrosoglutathione (GSNO) in glioma cells overexpressing inducible nitric oxide synthase (iNOS) contributed to nitric oxide (NO)-dependent carbamoylating chemoresistance against BCNU. To further characterize the effects of NO on alkylating cytotoxicity, colony formation assay was applied to evaluate the effects of various NO donors on rat C6 glioma cells challenged with alkylating agents. We demonstrate that NO donors including GSNO, diethylamine NONOate (DEA/NO), and sodium nitroprusside (SNP) substantially reduced the extent of colony formation in glioma cells treated with alkylating agents, namely methyl methanesulfonate (MMS), N-methyl-N-nitrosourea (MNU), and N-ethyl-N-nitrosourea (ENU). Without alkylating agents these NO-releasing agents alone had no effects on clongenic potential of rat C6 glioma cells. Among these three NO donors used, the effectiveness in potentiating alkylating cytotoxicity is in the order of "GSNO>DEA/NO>SNP" when applied at the same dosages. GSNO also exerted similar synergistic actions reducing the extents of colony formation when co-administrated with 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-hydrazine (compound #1), another alkylating agent that mimics the chloroethylating action of BCNU. Together with our previous findings, we propose that NO donors may be used as adjunct chemotherapy with alkylating agents for such malignant brain tumors as glioblastoma multiforme (GBM). In contrast, production of NO as a result of iNOS induction, such as that occurring after surgical resection of brain tumors, may compromise the efficacy of carbamoylating chemotherapy.

  19. Rapid and high-yield synthesis of carrier-free 18F-labelled alkyl fluorides

    International Nuclear Information System (INIS)

    Yagi, M.; Murano, Y.; Izawa, G.

    1982-01-01

    A convenient method for the rapid and high-yield synthesis of carrier-free 18 F-labelled alkyl fluorides was developed. The method involves (1) preparation of carrier-free 18 F-labelled silver fluoride on surface-oxidized silver wool as a fluorinating source for 18 F-labelling: and (2) synthesis of carrier-free 18 F-labelled alkyl fluoride by connecting the above source to a radio-gas chromatography, followed by ordinary gas chromatographic procedure. In the present method, the carrier-free 18 F-labelled alkyl fluorides are synthesized by means of nucleophilic substitution reaction in the heterogeneous gas-phase system. In order to examine the usefulness of the present method, syntheses of 12 carrier-free 18 F-labelled alkyl fluorides were tested using the corresponding bromo- and iodo-compounds as the reactants. Synthesis and isolation of the labelled product in each case were sufficiently rapid and efficient to allow production of usable amounts of the desired compound. (author)

  20. Inducible Alkylation of DNA by a Quinone Methide-Peptide Nucleic Acid Conjugate†

    Science.gov (United States)

    Liu, Yang; Rokita, Steven E.

    2012-01-01

    The reversibility of alkylation by a quinone methide intermediate (QM) avoids the irreversible consumption that plagues most reagents based on covalent chemistry and allows for site specific reaction that is controlled by the thermodynamics rather than kinetics of target association. This characteristic was originally examined with an oligonucleotide QM conjugate but broad application depends on alternative derivatives that are compatible with a cellular environment. Now, a peptide nucleic acid (PNA) derivative has been constructed and shown to exhibit an equivalent ability to delivery the reactive QM in a controlled manner. This new conjugate demonstrates high selectivity for a complementary sequence of DNA even when challenged with an alternative sequence containing a single T/T mismatch. Alkylation of non-complementary sequences is only possible when a template strand is present to co-localize the conjugate and its target. For efficient alkylation in this example, a single-stranded region of the target is required adjacent to the QM conjugate. Most importantly, the intrastrand self adducts formed between the PNA and its attached QM remained active and reversible over more than eight days in aqueous solution prior to reaction with a chosen target added subsequently. PMID:22243337

  1. ALKYL PYROPHOSPHATE METAL SOLVENT EXTRACTANTS AND PROCESS

    Science.gov (United States)

    Long, R.L.

    1958-09-30

    A process is presented for the recovery of uranium from aqueous mineral acidic solutions by solvent extraction. The extractant is a synmmetrical dialkyl pyrophosphate in which the alkyl substituents have a chain length of from 4 to 17 carbon atoms. Mentioned as a preferred extractant is dioctyl pyrophosphate. The uranium is precipitated irom the organic extractant phase with an agent such as HF, fluoride salts. alcohol, or ammonia.

  2. Mechanism of Phenol Alkylation in Zeolite H-BEA Using In Situ Solid-State NMR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhenchao [Institute; Shi, Hui [Institute; Wan, Chuan [Institute; Hu, Mary Y. [Institute; Liu, Yuanshuai [Department; Mei, Donghai [Institute; Camaioni, Donald M. [Institute; Hu, Jian Zhi [Institute; Lercher, Johannes A. [Institute; Department

    2017-06-27

    Alkylation of phenolic compounds in the liquid phase is of fundamental and practical importance to the conversion of biomass-derived feedstocks into fuels and chemicals. In this work, the reaction mechanism for phenol alkylation with cyclohexanol and cyclohexene has been investigated on a commercial HBEA zeolite by in situ 13C MAS NMR, using decalin as the solvent. From the variable temperature 13C MAS NMR measurements of phenol and cyclohexanol adsorption on HBEA from decalin solutions, it is shown that the two molecules have similar adsorption strength in the HBEA pore. Phenol alkylation with cyclohexanol, however, becomes significantly measurable only after cyclohexanol is largely converted to cyclohexene via dehydration. This is in contrast to the initially rapid alkylation of phenol when using cyclohexene as the co-reactant. 13C isotope scrambling results demonstrate that the electrophile, presumably cyclohexyl carbenium ion, is directly formed in a protonation step when cyclohexene is the co-reactant, but requires re-adsorption of the alcohol dehydration product, cyclohexene, when cyclohexanol dimer is the dominant surface species (e.g., at 0.5 M cyclohexanol concentration) that is unable to generate carbenium ion. At the initial reaction stage of phenol-cyclohexanol alkylation on HBEA, the presence of the cyclohexanol dimer species hinders the adsorption of cyclohexene at the Brønsted acid site and the subsequent activation of the more potent electrophile (carbenium ion). Isotope scrambling data also show that intramolecular rearrangement of cyclohexyl phenyl ether, the O-alkylation product, does not significantly contribute to the formation of C-alkylation products.

  3. A General Catalyst for Site-Selective C(sp(3))-H Bond Amination of Activated Secondary over Tertiary Alkyl C(sp(3))-H Bonds.

    Science.gov (United States)

    Scamp, Ryan J; Jirak, James G; Dolan, Nicholas S; Guzei, Ilia A; Schomaker, Jennifer M

    2016-06-17

    The discovery of transition metal complexes capable of promoting general, catalyst-controlled and selective carbon-hydrogen (C-H) bond amination of activated secondary C-H bonds over tertiary alkyl C(sp(3))-H bonds is challenging, as substrate control often dominates when reactive nitrene intermediates are involved. In this letter, we report the design of a new silver complex, [(Py5Me2)AgOTf]2, that displays general and good-to-excellent selectivity for nitrene insertion into propargylic, benzylic, and allylic C-H bonds over tertiary alkyl C(sp(3))-H bonds.

  4. DNA-directed alkylating ligands as potential antitumor agents: sequence specificity of alkylation by intercalating aniline mustards.

    Science.gov (United States)

    Prakash, A S; Denny, W A; Gourdie, T A; Valu, K K; Woodgate, P D; Wakelin, L P

    1990-10-23

    The sequence preferences for alkylation of a series of novel parasubstituted aniline mustards linked to the DNA-intercalating chromophore 9-aminoacridine by an alkyl chain of variable length were studied by using procedures analogous to Maxam-Gilbert reactions. The compounds alkylate DNA at both guanine and adenine sites. For mustards linked to the acridine by a short alkyl chain through a para O- or S-link group, 5'-GT sequences are the most preferred sites at which N7-guanine alkylation occurs. For analogues with longer chain lengths, the preference of 5'-GT sequences diminishes in favor of N7-adenine alkylation at the complementary 5'-AC sequence. Magnesium ions are shown to selectively inhibit alkylation at the N7 of adenine (in the major groove) by these compounds but not the alkylation at the N3 of adenine (in the minor groove) by the antitumor antibiotic CC-1065. Effects of chromophore variation were also studied by using aniline mustards linked to quinazoline and sterically hindered tert-butyl-9-aminoacridine chromophores. The results demonstrate that in this series of DNA-directed mustards the noncovalent interactions of the carrier chromophores with DNA significantly modify the sequence selectivity of alkylation by the mustard. Relationships between the DNA alkylation patterns of these compounds and their biological activities are discussed.

  5. Manganese-catalyzed Dehydrogenative Alkylation or α-Olefination of Alkyl-N-Heteroaromatics by Alcohols.

    Science.gov (United States)

    Kempe, Rhett; Zhang, Guoying; Irrgang, Torsten; Dietel, Thomas; Kallmeier, Fabian

    2018-05-02

    Catalysis involving earth-abundant transition metals is an option to help save our rare noble metal resources and is especially interesting if novel reactivity or selectivity patterns are observed. We report here on a novel reaction: the dehydrogenative alkylation or α-olefination of alkyl-N-heteroaromatics by alcohols. Manganese complexes developed in our laboratory catalyze the reaction efficiently. Fe and Co complexes stabilized by such ligands are essentially inactive. Hydrogen is liberated during the reaction and bromo or iodo functional groups and olefins can be tolerated. A variety of alkyl-N-heteroaromatics can be functionalized, and benzyl and aliphatic alcohols undergo the reaction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Mobile communication and intermediality

    DEFF Research Database (Denmark)

    Helles, Rasmus

    2013-01-01

    The article argues the importance of intermediality as a concept for research in mobile communication and media. The constant availability of several, partially overlapping channels for communication (texting, calls, email, Facebook, etc.) requires that we adopt an integrated view of the various...

  7. an intermediate moisture meat

    African Journals Online (AJOL)

    Bunmi

    Matured leaves of Ocimum gratissimum were harvested and the extracts used to cure. Suya (an intermediate moisture meat). O. gratissimum leaves were collected from. Oyo state south west region of Nigeria, rinsed in distilled water and squeezed to extract the fluid. The meat used was Semi membranosus muscle from beef ...

  8. Visible light- and radiation-induced alkylation of pyridine ring with alkanoic acid

    International Nuclear Information System (INIS)

    Sugimori, Akira; Yamada, Tetsuo

    1986-01-01

    Quinoline and 4-methylquinoline are efficiently alkylated with alkanoic acid in the presence of iron(III) sulfate upon visible light-irradiation. Iron(III) sulfate not only accelerates the photoreaction but also increases the yield of alkylation. Gamma-irradiation also brings about the alkylation. In the photo- and radiation-induced alkylation with alkanoic acid, alkyl radicals play important roles. (author)

  9. Alkylation damage by lipid electrophiles targets functional protein systems.

    Science.gov (United States)

    Codreanu, Simona G; Ullery, Jody C; Zhu, Jing; Tallman, Keri A; Beavers, William N; Porter, Ned A; Marnett, Lawrence J; Zhang, Bing; Liebler, Daniel C

    2014-03-01

    Protein alkylation by reactive electrophiles contributes to chemical toxicities and oxidative stress, but the functional impact of alkylation damage across proteomes is poorly understood. We used Click chemistry and shotgun proteomics to profile the accumulation of proteome damage in human cells treated with lipid electrophile probes. Protein target profiles revealed three damage susceptibility classes, as well as proteins that were highly resistant to alkylation. Damage occurred selectively across functional protein interaction networks, with the most highly alkylation-susceptible proteins mapping to networks involved in cytoskeletal regulation. Proteins with lower damage susceptibility mapped to networks involved in protein synthesis and turnover and were alkylated only at electrophile concentrations that caused significant toxicity. Hierarchical susceptibility of proteome systems to alkylation may allow cells to survive sublethal damage while protecting critical cell functions.

  10. Alkylation Damage by Lipid Electrophiles Targets Functional Protein Systems*

    Science.gov (United States)

    Codreanu, Simona G.; Ullery, Jody C.; Zhu, Jing; Tallman, Keri A.; Beavers, William N.; Porter, Ned A.; Marnett, Lawrence J.; Zhang, Bing; Liebler, Daniel C.

    2014-01-01

    Protein alkylation by reactive electrophiles contributes to chemical toxicities and oxidative stress, but the functional impact of alkylation damage across proteomes is poorly understood. We used Click chemistry and shotgun proteomics to profile the accumulation of proteome damage in human cells treated with lipid electrophile probes. Protein target profiles revealed three damage susceptibility classes, as well as proteins that were highly resistant to alkylation. Damage occurred selectively across functional protein interaction networks, with the most highly alkylation-susceptible proteins mapping to networks involved in cytoskeletal regulation. Proteins with lower damage susceptibility mapped to networks involved in protein synthesis and turnover and were alkylated only at electrophile concentrations that caused significant toxicity. Hierarchical susceptibility of proteome systems to alkylation may allow cells to survive sublethal damage while protecting critical cell functions. PMID:24429493

  11. Copper-catalyzed radical carbooxygenation: alkylation and alkoxylation of styrenes.

    Science.gov (United States)

    Liao, Zhixiong; Yi, Hong; Li, Zheng; Fan, Chao; Zhang, Xu; Liu, Jie; Deng, Zixin; Lei, Aiwen

    2015-01-01

    A simple copper-catalyzed direct radical carbooxygenation of styrenes is developed utilizing alkyl bromides as radical resources. This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of styrenes in one pot. A broad range of styrenes and alcohols are well tolerated in this transformation. The EPR experiment shows that alkyl halides could oxidize Cu(I) to Cu(II) in this transformation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A new strategy for aromatic ring alkylation in cylindrocyclophane biosynthesis.

    Science.gov (United States)

    Nakamura, Hitomi; Schultz, Erica E; Balskus, Emily P

    2017-08-01

    Alkylation of aromatic rings with alkyl halides is an important transformation in organic synthesis, yet an enzymatic equivalent is unknown. Here, we report that cylindrocyclophane biosynthesis in Cylindrospermum licheniforme ATCC 29412 involves chlorination of an unactivated carbon center by a novel halogenase, followed by a previously uncharacterized enzymatic dimerization reaction featuring sequential, stereospecific alkylations of resorcinol aromatic rings. Discovery of the enzymatic machinery underlying this unique biosynthetic carbon-carbon bond formation has implications for biocatalysis and metabolic engineering.

  13. 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...... for the development of allylic C-H alkylation into a widely applicable methodology, thus providing a means to enhance synthetic efficiency in these reactions....

  14. Possible targets for the aneugenic activity of alkylating agents

    Energy Technology Data Exchange (ETDEWEB)

    Pellerano, P. [IST-National Institute for Research on Cancer, Genova (Italy); Abbondandolo, A. [Univ. of Genova (Italy); Bonatti, S.; Simili, M. [CNR Institute of Mutagenesis and Differentiation, Pisa (Italy)

    1993-12-31

    Alkylating agents have been of invaluable help in mutation research for half a century. In all tested organisms, they have proved able to induce a large variety of genetic effects, including aneuploidy. Credible molecular models exist to explain the ability of alkylating agents to induce gene mutation and to act as initiators in carcinogenesis as a consequence of DNA alkylation at specific sites. On the contrary, neither the mechanism of aneuploidy induction nor the relevant cellular targets are known.

  15. Microbial metabolism of alkyl and condensed thiophenes: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fedorak, P.M.

    1992-01-01

    This study was conducted to gain a better understanding of the metabolic pathways used by aerobic microorganisms for the biodegradation or biotransformation of organosulfur compounds found in petroleum. The study used alkyl-substituted thiophenes, benzothiophene and alkyl-substituted benzothiophenes and alkyl-substituted dibenzothiophenes. The results provide information relevant to environmental matters, aspects of microbial transformations in petroleum reservoirs and further assessment of the feasibility of biodesulfurization.

  16. Evaluation of antioxidant enzymes activities and identification of intermediate products during phytoremediation of an anionic dye (C.I. Acid Blue 92) by pennywort (Hydrocotyle vulgaris).

    Science.gov (United States)

    Vafaei, Fatemeh; Movafeghi, Ali; Khataee, Alireza

    2013-11-01

    The potential of pennywort (Hydrocotyle vulgaris) for phytoremediation of C.I. Acid Blue 92 (AB92) was evaluated. The effects of various experimental parameters including pH, temperature, dye concentration and plant weight on dye removal efficiency were investigated. The results showed that the optimal condition for dye removal were pH 3.5 and temperature 25 degree C. Moreover, the absolute dye removal enhanced with increase in the initial dye concentration and plant weight. Pennywort showed the same removal efficiency in repeated experiments (four runs) as that obtained from the first run (a 6-day period). Therefore, the ability of the plant in consecutive removal of AB92 confirmed the biodegradation process. Accordingly, a number of produced intermediate compounds were identified. The effect of treatment on photosynthesis and antioxidant defense system including superoxide dismutase, peroxidase and catalase in plant roots and leaves were evaluated. The results revealed a reduction in photosynthetic pigments content under dye treatments. Antioxidant enzyme responses showed marked variations with respect to the plant organ and dye concentration in the liquid medium. Overall, the increase in antioxidant enzyme activity under AB92 stress in the roots was much higher than that in the leaves. Nevertheless, no significant increase in malondialdehyde content was detected in roots or leaves, implying that the high efficiency of antioxidant system in the elimination of reactive oxygen species. Based on these results, pennywort was founded to be a capable species for phytoremediation of AB92-contaminated water, may be effective for phytoremediation dye-contaminated polluted aquatic ecosystems.

  17. Excretory/secretory products in the Echinococcus granulosus metacestode: is the intermediate host complacent with infection caused by the larval form of the parasite?

    Science.gov (United States)

    Santos, Guilherme B Dos; Monteiro, Karina M; da Silva, Edileuza Danieli; Battistella, Maria Eduarda; Ferreira, Henrique B; Zaha, Arnaldo

    2016-12-01

    The genus Echinococcus consists of parasites that have a life cycle with two mammalian hosts. Their larval stage, called the hydatid cyst, develops predominantly in the liver and lungs of intermediate hosts. The hydatid cyst is the causative agent of cystic hydatid disease and the species Echinococcus granulosus, G1 haplotype, is responsible for the vast majority of cases in humans, cattle and sheep. Protein characterization in hydatid cysts is essential for better understanding of the host-parasite relationship and the fertility process of Echinococcus. The aims of this work were the identification and quantitative comparison of proteins found in hydatid fluid from fertile and infertile cysts from E. granulosus, in order to highlight possible mechanisms involved in cyst fertility or infertility. Hydatid fluid samples containing proteins from both E. granulosus and Bos taurus were analysed by LC-MS/MS. Our proteomic analysis of fertile and infertile cysts allowed identification of a total of 498 proteins, of which 153 proteins were exclusively identified in the fertile cyst, 271 in the infertile cyst, and 74 in both. Functional in silico analysis allowed us to highlight some important aspects: (i) clues about the possible existence of an "arms race" involving parasite and host responses in fertile and infertile cysts; (ii) a number of proteins in hydatid fluid without functional annotation or with possible alternative functions; (iii) the presence of extracellular vesicles such as exosomes, which was confirmed by transmission electron microscopy. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  18. Catalytic enantioselective synthesis of atropisomeric biaryls by a cation-directed O-alkylation

    Science.gov (United States)

    Jolliffe, John D.; Armstrong, Roly J.; Smith, Martin D.

    2017-06-01

    Axially chiral biaryls, as exemplified by 1,1‧-bi-2-naphthol (BINOL), are key components of catalysts, natural products and medicines. These materials are synthesized conventionally in enantioenriched form through metal-mediated cross coupling, de novo construction of an aromatic ring, point-to-axial chirality transfer or an atropselective transformation of an existing biaryl. Here, we report a highly enantioselective organocatalytic method for the synthesis of atropisomeric biaryls by a cation-directed O-alkylation. Treatment of racemic 1-aryl-2-tetralones with a chiral quinidine-derived ammonium salt under basic conditions in the presence of an alkylating agent leads to atropselective O-alkylation with e.r. up to 98:2. Oxidation with DDQ gives access to C2-symmetric and non-symmetric BINOL derivatives without compromising e.r. We propose that the chiral ammonium counterion differentiates between rapidly equilibrating atropisomeric enolates, leading to highly atropselective O-alkylation. This dynamic kinetic resolution process offers a general approach to the synthesis of enantioenriched atropisomeric materials.

  19. The use of polynuclear aromatic hydrocarbon (PAH) alkyl homologues in determining petroleum source identification and weathering

    International Nuclear Information System (INIS)

    Brown, J.S.; Boehm, P.D.; Sauer, T.C.; Wong, W.M.C.

    1993-01-01

    Techniques utilizing double ratio plots of selected polynuclear aromatic hydrocarbon (PAH) alkyl homologues were used to identify and distinguish crude oils and refined petroleum products from each other and to distinguish petroleum sources in complex pollutant regimes. Petroleum samples were fractionated by high performance liquid chromatography (HPLC) into saturated and aromatic (PAH) hydrocarbon fractions. The saturated hydrocarbon fractions were then analyzed by gas chromatography/flame ionization detection (GC/FID) to obtain a resolved/unresolved alkane fingerprint of each oil. The aromatic fractions of the oils were analyzed by gas chromatography/mass spectrometry (GC/MS) for PAH and selected alkyl homologues. Comparisons of the saturated hydrocarbon fingerprints indicated that some oils were indistinguishable based on the alkane fingerprint alone. Another double ratio plot of the alkyl chrysenes and alkyl dibenzothiophenes was effective in establishing the weathering of oil in environmental samples which were processed using the same analytical techniques, since the dibenzothiophenes are degraded more rapidly than the chrysenes. The application of selected ratios in oil spill source identification in complex environmental samples from Suisin Bay California and Boston Harbor are discussed. The use of ratios to measure the extent of weathering in oil spill samples from Prince William Sound and the Gulf of Alaska is examined

  20. Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C−O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination

    KAUST Repository

    Liu, Xiangqian

    2016-04-10

    In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting β-hydride elimination. This new nickel-catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process.

  1. Development of novel alkylating drugs as anticancer agents.

    Science.gov (United States)

    Izbicka, Elzbieta; Tolcher, Anthony W

    2004-06-01

    Although conventional alkylating drugs have proven efficacy in the treatment of malignancies, the agents themselves are not selective. Therefore, non-specific alkylation of cellular nucleophilic targets may contribute to many of the observed toxic effects. Novel approaches to drug discovery have resulted in candidate agents that are focused on 'soft alkylation'--alkylators with greater target selectivity. This review highlights the discovery of small molecule drugs that bind to DNA with higher selectivity, act in a unique hypoxic tumor environment, or covalently bind specific protein targets overexpressed in cancer, such as topoisomerase II, glutathione transferase pi1, beta-tubulin and histone deacetylase.

  2. The antimalarial drug artemisinin alkylates heme in infected mice

    Science.gov (United States)

    Robert, Anne; Benoit-Vical, Françoise; Claparols, Catherine; Meunier, Bernard

    2005-01-01

    Heme alkylation by the antimalarial drug artemisinin is reported in vivo, within infected mice that have been treated at pharmacologically relevant doses. Adducts resulting from the alkylation of heme by the drug were characterized in the spleen of treated mice, and their glucuroconjugated derivatives were present in the urine. Because these heme-artemisinin adducts were not observed in noninfected mice, this report confirms that the alkylating activity of this antimalarial drug is related to the presence of the parasite in infected animals. The identification of heme-artemisinin adducts in mice should be considered as the signature of the alkylation capacity of artemisinin in vivo. PMID:16155128

  3. Immunological detection and quantification of DNA components structurally modified by alkylating carcinogens, mutagens and chemotherapeutic agents

    International Nuclear Information System (INIS)

    Rajewsky, M.F.

    1983-01-01

    The detection and quantification of defined reaction products of chemical mutagens and carcinogens (and of many cancer chemotherapeutic agents) with DNA require highly sensitive analytical techniques. The exceptional capability of immunoglobulins to recognize subtle alterations of molecular structure (especially when monoclonal antibodies are used to maximize specificity), outstanding sensitivity of immunoanalysis by high-affinity antibodies, and the fact that radioactively-labelled agents are not required suggest the utility of a radioimmunoassay to recognize and quantitate alkylated DNA products. We have recently developed a set of high-affinity monoclonal antibodies (secreted by mouse x mouse as well as by rat x rat hybridomas; antibody affinity constants, 10 9 to > 10 10 lmol) specifically directed against several DNA alkylation products with possible relevance in relation to both mutagenesis and malignant transformation of mammalian cells. These alkylation products include 0 6 -N-butyldeoxyguanosine, and 0 4 -ethyldeoxythymidine. When used in a radioimmunassay, an antibody specific for 0 6 -ethyldeoxyguanosine, for example, will detect this product at an 0 6 -ethyldeoxyguanosine/deoxyguanosine molar ratio of approx. 3 x 10 -7 in a hydrolysate of 100 ug of DNA. The limit of detection can be lowered further if the respective alkyldeoxynucleosides are separated by HPLC from the DNA hydrolysate prior to the RIA. The anti-alkyldeoxynucleoside monoclonal antibodies can also be used to visualize, by immunostaining and fluorescence microscopy combined with electronic image intensification, specific alkylation products in the nuclear DNA of individual cells, and to localize structurally modified bases in double-stranded DNA molecules by transmission electron microscopy

  4. Reichardt's dye and its reactions with the alkylating agents 4-chloro-1-butanol, ethyl methanesulfonate, 1-bromobutane and Fast Red B - a potentially useful reagent for the detection of genotoxic impurities in pharmaceuticals.

    Science.gov (United States)

    Corrigan, Damion K; Whitcombe, Michael J; McCrossen, Sean; Piletsky, Sergey

    2009-04-01

    Alkylating agents are potentially genotoxic impurities that may be present in drug products. These impurities occur in pharmaceuticals as by-products from the synthetic steps involved in drug production, as impurities in starting materials or from in-situ reactions that take place in the final drug product. Currently, analysis for genotoxic impurities is typically carried out using either HPLC/MS or GC/MS. These techniques require specialist expertise, have long analysis times and often use sample clean-up procedures. Reichardt's dye is well known for its solvatochromic properties. In this paper the dye's ability to undergo alkylation is reported. The reaction between Reichardt's dye and alkylating agents such as 4-chloro-1-butanol and ethyl methanesulfonate was monitored spectrophotometrically at 618 nm in acetonitrile and 624 nm in N,N-dimethylformamide. Changes in absorption were observed using low levels of alkylating agent (5-10 parts per million). Alkylation of the dye with 4-chloro-1-butanol and ethyl methanesulfonate was confirmed. Reichardt's dye, and its changing UV absorption, was examined in the presence of paracetamol (10 and 100 mg/ml). Whilst the alkylation-induced changes in UV absorption were not as pronounced as with standard solutions, detection of alkylation was still possible. Using standard solutions and in the presence of a drug matrix, Reichardt's dye shows promise as a reagent for detection of low levels of industrially important alkylating agents.

  5. Contemporary presence of dynamical and statistical production of intermediate mass fragments in midperipheral 58Ni/+58Ni collisions at 30 /MeV/nucleon

    Science.gov (United States)

    Milazzo, P. M.; Vannini, G.; Sisto, M.; Agodi, C.; Alba, R.; Bellia, G.; Belkacem, M.; Bruno, M.; Colonna, M.; Colonna, N.; Coniglione, R.; D'Agostino, M.; Del Zoppo, A.; Fabbietti, L.; Finocchiaro, P.; Gramegna, F.; Iori, I.; Loukachine, K.; Maiolino, C.; Margagliotti, G. V.; Mastinu, P. F.; Migneco, E.; Moroni, A.; Piattelli, P.; Rui, R.; Santonocito, D.; Sapienza, P.; Ventura, P.

    2001-06-01

    The 58Ni+58Ni reaction at 30 /MeV/nucleon has been experimentally investigated at the Superconducting Cyclotron of the INFN Laboratori Nazionali del Sud. In midperipheral collisions the production of massive fragments (/4<=Z<=12), consistent with the statistical fragmentation of the projectile-like residue and the dynamical formation of a neck, joining projectile-like and target-like residues, has been observed. The fragments coming from these different processes differ both in charge distribution and isotopic composition. In particular it is shown that these mechanisms leading to fragment production act contemporarily inside the same event.

  6. UV Photodissociation Dynamics of the CH3CHOO Criegee Intermediate: Action Spectroscopy and Velocity Map Imaging of O-Atom Products.

    Science.gov (United States)

    Li, Hongwei; Fang, Yi; Kidwell, Nathanael M; Beames, Joseph M; Lester, Marsha I

    2015-07-30

    UV excitation of jet-cooled CH3CHOO on the B(1)A'-X(1)A' transition results in dissociation to two spin-allowed product channels: CH3CHO X(1)A' + O (1)D and CH3CHO a(3)A″ + O (3)P. The O (1)D and O (3)P products are detected using 2 + 1 REMPI at 205 and 226 nm, respectively, for action spectroscopy and velocity map imaging studies. The O (1)D action spectrum closely follows the previously reported UV absorption spectrum for jet-cooled CH3CHOO [Beames et al. J. Chem. Phys. 2013 , 138 , 244307]. Velocity map images of the O (1)D products following excitation of CH3CHOO at 305, 320, and 350 nm exhibit anisotropic angular distributions indicative of rapid (ps) dissociation, along with broad and unstructured total kinetic energy (TKER) distributions that reflect the internal energy distribution of the CH3CHO X(1)A' coproducts. The O (3)P action spectrum turns on near the peak of the UV absorption spectrum (ca. 324 nm) and extends to higher energy with steadily increasing O (3)P yield. Excitation of CH3CHOO at 305 nm, attributed to absorption of the more stable syn-conformer, also results in an anisotropic angular distribution of O (3)P products arising from rapid (ps) dissociation, but a narrower TKER distribution since less energy is available to the CH3CHO a(3)A″ + O (3)P products. The threshold for the higher energy CH3CHO a(3)A″ + O (3)P product channel is determined to be ca. 88.4 kcal mol(-1) from the termination of the TKER distribution and the onset of the O (3)P action spectrum. This threshold is combined with the singlet-triplet spacings of O atoms and acetaldehyde to establish the dissociation energy for syn-CH3HOO X(1)A' to the lowest spin-allowed product channel, CH3CHO X(1)A' + O (1)D, of ≤55.9 ± 0.4 kcal mol(-1). A harmonic normal-mode analysis is utilized to identify the vibrational modes of CH3CHO likely to be excited upon dissociation into the two product channels.

  7. Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds.

    Science.gov (United States)

    Pindwal, Aradhana; Yan, KaKing; Patnaik, Smita; Schmidt, Bradley M; Ellern, Arkady; Slowing, Igor I; Bae, Cheolbeom; Sadow, Aaron D

    2017-11-22

    Homoleptic tris(alkyl) rare earth complexes Ln{C(SiHMe 2 ) 3 } 3 (Ln = La, 1a; Ce, 1b; Pr, 1c; Nd, 1d) are synthesized in high yield from LnI 3 THF n and 3 equiv of KC(SiHMe 2 ) 3 . X-ray diffraction studies reveal 1a-d are isostructural, pseudo-C 3 -symmetric molecules that contain two secondary Ln↼HSi interactions per alkyl ligand (six total). Spectroscopic assignments are supported by comparison with Ln{C(SiDMe 2 ) 3 } 3 and DFT calculations. The Ln↼HSi and terminal SiH exchange rapidly on the NMR time scale at room temperature, but the two motifs are resolved at low temperature. Variable-temperature NMR studies provide activation parameters for the exchange process in 1a (ΔH ⧧ = 8.2(4) kcal·mol -1 ; ΔS ⧧ = -1(2) cal·mol -1 K -1 ) and 1a-d 9 (ΔH ⧧ = 7.7(3) kcal·mol -1 ; ΔS ⧧ = -4(2) cal·mol -1 K -1 ). Comparisons of lineshapes, rate constants (k H /k D ), and slopes of ln(k/T) vs 1/T plots for 1a and 1a-d 9 reveal that an inverse isotope effect dominates at low temperature. DFT calculations identify four low-energy intermediates containing five β-Si-H⇀Ln and one γ-C-H⇀Ln. The calculations also suggest the pathway for Ln↼HSi/SiH exchange involves rotation of a single C(SiHMe 2 ) 3 ligand that is coordinated to the Ln center through the Ln-C bond and one secondary interaction. These robust organometallic compounds persist in solution and in the solid state up to 80 °C, providing potential for their use in a range of synthetic applications. For example, reactions of Ln{C(SiHMe 2 ) 3 } 3 and ancillary proligands, such as bis-1,1-(4,4-dimethyl-2-oxazolinyl)ethane (HMeC(Ox Me2 ) 2 ) give {MeC(Ox Me2 ) 2 }Ln{C(SiHMe 2 ) 3 } 2 , and reactions with disilazanes provide solvent-free lanthanoid tris(disilazides).

  8. The Intermediate Neutrino Program

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C.; et al.

    2015-03-23

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

  9. The Intermediate Neutrino Program

    CERN Document Server

    Adams, C.; Ankowski, A.M.; Asaadi, J.A.; Ashenfelter, J.; Axani, S.N.; Babu, K.; Backhouse, C.; Band, H.R.; Barbeau, P.S.; Barros, N.; Bernstein, A.; Betancourt, M.; Bishai, M.; Blucher, E.; Bouffard, J.; Bowden, N.; Brice, S.; Bryan, C.; Camilleri, L.; Cao, J.; Carlson, J.; Carr, R.E.; Chatterjee, A.; Chen, M.; Chen, S.; Chiu, M.; Church, E.D.; Collar, J.I.; Collin, G.; Conrad, J.M.; Convery, M.R.; Cooper, R.L.; Cowen, D.; Davoudiasl, H.; de Gouvea, A.; Dean, D.J.; Deichert, G.; Descamps, F.; DeYoung, T.; Diwan, M.V.; Djurcic, Z.; Dolinski, M.J.; Dolph, J.; Donnelly, B.; Dwyer, D.A.; Dytman, S.; Efremenko, Y.; Everett, L.L.; Fava, A.; Figueroa-Feliciano, E.; Fleming, B.; Friedland, A.; Fujikawa, B.K.; Gaisser, T.K.; Galeazzi, M.; Galehouse, D.C.; Galindo-Uribarri, A.; Garvey, G.T.; Gautam, S.; Gilje, K.E.; Gonzalez-Garcia, M.; Goodman, M.C.; Gordon, H.; Gramellini, E.; Green, M.P.; Guglielmi, A.; Hackenburg, R.W.; Hackenburg, A.; Halzen, F.; Han, K.; Hans, S.; Harris, D.; Heeger, K.M.; Herman, M.; Hill, R.; Holin, A.; Huber, P.; Jaffe, D.E.; Johnson, R.A.; Joshi, J.; Karagiorgi, G.; Kaufman, L.J.; Kayser, B.; Kettell, S.H.; Kirby, B.J.; Klein, J.R.; Kolomensky, Yu. G.; Kriske, R.M.; Lane, C.E.; Langford, T.J.; Lankford, A.; Lau, K.; Learned, J.G.; Ling, J.; Link, J.M.; Lissauer, D.; Littenberg, L.; Littlejohn, B.R.; Lockwitz, S.; Lokajicek, M.; Louis, W.C.; Luk, K.; Lykken, J.; Marciano, W.J.; Maricic, J.; Markoff, D.M.; Martinez Caicedo, D.A.; Mauger, C.; Mavrokoridis, K.; McCluskey, E.; McKeen, D.; McKeown, R.; Mills, G.; Mocioiu, I.; Monreal, B.; Mooney, M.R.; Morfin, J.G.; Mumm, P.; Napolitano, J.; Neilson, R.; Nelson, J.K.; Nessi, M.; Norcini, D.; Nova, F.; Nygren, D.R.; Orebi Gann, G.D.; Palamara, O.; Parsa, Z.; Patterson, R.; Paul, P.; Pocar, A.; Qian, X.; Raaf, J.L.; Rameika, R.; Ranucci, G.; Ray, H.; Reyna, D.; Rich, G.C.; Rodrigues, P.; Romero, E.Romero; Rosero, R.; Rountree, S.D.; Rybolt, B.; Sanchez, M.C.; Santucci, G.; Schmitz, D.; Scholberg, K.; Seckel, D.; Shaevitz, M.; Shrock, R.; Smy, M.B.; Soderberg, M.; Sonzogni, A.; Sousa, A.B.; Spitz, J.; St. John, J.M.; Stewart, J.; Strait, J.B.; Sullivan, G.; Svoboda, R.; Szelc, A.M.; Tayloe, R.; Thomson, M.A.; Toups, M.; Vacheret, A.; Vagins, M.; Van de Water, R.G.; Vogelaar, R.B.; Weber, M.; Weng, W.; Wetstein, M.; White, C.; White, B.R.; Whitehead, L.; Whittington, D.W.; Wilking, M.J.; Wilson, R.J.; Wilson, P.; Winklehner, D.; Winn, D.R.; Worcester, E.; Yang, L.; Yeh, M.; Yokley, Z.W.; Yoo, J.; Yu, B.; Yu, J.; Zhang, C.

    2015-01-01

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summ...

  10. The Intermediate Neutrino Program

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C. [Yale Univ., New Haven, CT (United States); Alonso, J. R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Ankowski, A. M. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Asaadi, J. A. [Syracuse Univ., NY (United States); Ashenfelter, J. [Yale Univ., New Haven, CT (United States); Axani, S. N. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Babu, K [Oklahoma State Univ., Stillwater, OK (United States); Backhouse, C. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Band, H. R. [Yale Univ., New Haven, CT (United States); Barbeau, P. S. [Duke Univ., Durham, NC (United States); Barros, N. [Univ. of Pennsylvania, Philadelphia, PA (United States); Bernstein, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Betancourt, M. [Illinois Inst. of Technology, Chicago, IL (United States); Bishai, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blucher, E. [Univ. of Chicago, IL (United States); Bouffard, J. [State Univ. of New York (SUNY), Albany, NY (United States); Bowden, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brice, S. [Illinois Inst. of Technology, Chicago, IL (United States); Bryan, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Camilleri, L. [Columbia Univ., New York, NY (United States); Cao, J. [Inst. of High Energy Physics, Beijing (China); Carlson, J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carr, R. E. [Columbia Univ., New York, NY (United States); Chatterjee, A. [Univ. of Texas, Arlington, TX (United States); Chen, M. [Univ. of California, Irvine, CA (United States); Chen, S. [Tsinghua Univ., Beijing (China); Chiu, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Church, E. D. [Illinois Inst. of Technology, Chicago, IL (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Collar, J. I. [Univ. of Chicago, IL (United States); Collin, G. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Conrad, J. M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Convery, M. R. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Cooper, R. L. [Indiana Univ., Bloomington, IN (United States); Cowen, D. [Pennsylvania State Univ., University Park, PA (United States); Davoudiasl, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gouvea, A. D. [Northwestern Univ., Evanston, IL (United States); Dean, D. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deichert, G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Descamps, F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); DeYoung, T. [Michigan State Univ., East Lansing, MI (United States); Diwan, M. V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Djurcic, Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Dolinski, M. J. [Drexel Univ., Philadelphia, PA (United States); Dolph, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Donnelly, B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Dwyer, D. A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dytman, S. [Univ. of Pittsburgh, PA (United States); Efremenko, Y. [Univ. of Tennessee, Knoxville, TN (United States); Everett, L. L. [Univ. of Wisconsin, Madison, WI (United States); Fava, A. [University of Padua, Padova (Italy); Figueroa-Feliciano, E. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Fleming, B. [Yale Univ., New Haven, CT (United States); Friedland, A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fujikawa, B. K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gaisser, T. K. [Univ. of Delaware, Newark, DE (United States); Galeazzi, M. [Univ. of Miami, FL (United States); Galehouse, DC [Univ. of Akron, OH (United States); Galindo-Uribarri, A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Garvey, G. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gautam, S. [Tribhuvan Univ., Kirtipur (Nepal); Gilje, K. E. [Illinois Inst. of Technology, Chicago, IL (United States); Gonzalez-Garcia, M. [Stony Brook Univ., NY (United States); Goodman, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Gordon, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gramellini, E. [Yale Univ., New Haven, CT (United States); Green, M. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guglielmi, A. [University of Padua, Padova (Italy); Hackenburg, R. W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hackenburg, A. [Yale Univ., New Haven, CT (United States); Halzen, F. [Univ. of Wisconsin, Madison, WI (United States); Han, K. [Yale Univ., New Haven, CT (United States); Hans, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Harris, D. [Illinois Inst. of Technology, Chicago, IL (United States); Heeger, K. M. [Yale Univ., New Haven, CT (United States); Herman, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hill, R. [Univ. of Chicago, IL (United States); Holin, A. [Univ. College London, Bloomsbury (United Kingdom); Huber, P. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Jaffe, D. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Johnson, R. A. [Univ. of Cincinnati, OH (United States); Joshi, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Karagiorgi, G. [Univ. of Manchester (United Kingdom); Kaufman, L. J. [Indiana Univ., Bloomington, IN (United States); Kayser, B. [Illinois Inst. of Technology, Chicago, IL (United States); Kettell, S. H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Kirby, B. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Klein, J. R. [Univ. of Texas, Arlington, TX (United States); Kolomensky, Y. G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Kriske, R. M. [Univ. of Minnesota, Minneapolis, MN (United States); Lane, C. E. [Drexel Univ., Philadelphia, PA (United States); Langford, T. J. [Yale Univ., New Haven, CT (United States); Lankford, A. [Univ. of California, Irvine, CA (United States); Lau, K. [Univ. of Houston, TX (United States); Learned, J. G. [Univ. of Hawaii, Honolulu, HI (United States); Ling, J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Link, J. M. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Lissauer, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Littenberg, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Littlejohn, B. R. [Illinois Inst. of Technology, Chicago, IL (United States); Lockwitz, S. [Illinois Inst. of Technology, Chicago, IL (United States); Lokajicek, M. [Inst. of Physics of the Academy of Sciences of Czech Republic, Prague (Czech Republic); Louis, W. C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Luk, K. [Univ. of California, Berkeley, CA (United States); Lykken, J. [Illinois Inst. of Technology, Chicago, IL (United States); Marciano, W. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Maricic, J. [Univ. of Hawaii, Honolulu, HI (United States); Markoff, D. M. [North Carolina Central Univ., Durham, NC (United States); Caicedo, D. A. M. [Illinois Inst. of Technology, Chicago, IL (United States); Mauger, C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mavrokoridis, K. [Univ. of Liverpool (United Kingdom); McCluskey, E. [Illinois Inst. of Technology, Chicago, IL (United States); McKeen, D. [Univ. of Washington, Seattle, WA (United States); McKeown, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mills, G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocioiu, I. [Pennsylvania State Univ., University Park, PA (United States); Monreal, B. [Univ. of California, Santa Barbara, CA (United States); Mooney, M. R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morfin, J. G. [Illinois Inst. of Technology, Chicago, IL (United States); Mumm, P. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Napolitano, J. [Temple Univ., Philadelphia, PA (United States); Neilson, R. [Drexel Univ., Philadelphia, PA (United States); Nelson, J. K. [College of William and Mary, Williamsburg, VA (United States); Nessi, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Norcini, D. [Yale Univ., New Haven, CT (United States); Nova, F. [Univ. of Texas, Austin, TX (United States); Nygren, D. R. [Univ. of Texas, Arlington, TX (United States); Gann, GDO [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Palamara, O. [Illinois Inst. of Technology, Chicago, IL (United States); Parsa, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States); Patterson, R. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Paul, P. [Stony Brook Univ., NY (United States); Pocar, A. [Univ. of Massachusetts, Amherst, MA (United States); Qian, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Raaf, J. L. [Illinois Inst. of Technology, Chicago, IL (United States); Rameika, R. [Illinois Inst. of Technology, Chicago, IL (United States); Ranucci, G. [National Inst. of Nuclear Physics, Milano (Italy); Ray, H. [Univ. of Florida, Gainesville, FL (United States); Reyna, D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rich, G. C. [Triangle Universities Nuclear Lab., Durham, NC (United States); Rodrigues, P. [Univ. of Rochester, NY (United States); Romero, E. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Rosero, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rountree, S. D. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Rybolt, B. [Univ. of Tennessee, Knoxville, TN (United States); Sanchez, M. C. [Iowa State Univ., Ames, IA (United States); Santucci, G. [Stony Brook Univ., NY (United States); Schmitz, D. [Univ. of Chicago, IL (United States); Scholberg, K. [Duke Univ., Durham, NC (United States); Seckel, D. [Univ. of Delaware, Newark, DE (United States); Shaevitz, M. [Columbia Univ., New York, NY (United States); Shrock, R. [Stony Brook Univ., NY (United States); Smy, M. B. [Univ. of California, Irvine, CA (United States); Soderberg, M. [Syracuse Univ., NY (United States); Sonzogni, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sousa, A. B. [Univ. of Cincinnati, OH (United States); Spitz, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); John, J. M. S. [Univ. of Cincinnati, OH (United States); Stewart, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Strait, J. B. [Illinois Inst. of Technology, Chicago, IL (United States); Sullivan, G. [Univ. of Maryland, College Park, MD (United States); Svoboda, R. [Univ. of California, Davis, CA (United States); Szelc, A. M. [Yale Univ., New Haven, CT (United States); Tayloe, R. [Indiana Univ., Bloomington, IN (United States); Thomson, M. A. [Univ. of Cambridge (United Kingdom); Toups, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Vacheret, A. [Univ. of Oxford (United Kingdom); Vagins, M. [Univ. of California, Irvine, CA (United States); Water, R. G. V. D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vogelaar, R. B. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Weber, M. [Bern (Switzerland); Weng, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wetstein, M. [Univ. of Chicago, IL (United States); White, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); White, B. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Whitehead, L. [Univ. of Houston, TX (United States); Whittington, D. W. [Indiana Univ., Bloomington, IN (United States); Wilking, M. J. [Stony Brook Univ., NY (United States); Wilson, R. J. [Colorado State Univ., Fort Collins, CO (United States); Wilson, P. [Illinois Inst. of Technology, Chicago, IL (United States); Winklehner, D. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Winn, D. R. [Fairfield Univ., CT (United States); Worcester, E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yang, L. [Univ. of Illinois, Urbana-Champaign, IL (United States); Yeh, M [Brookhaven National Lab. (BNL), Upton, NY (United States); Yokley, Z. W. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Yoo, J. [Illinois Inst. of Technology, Chicago, IL (United States); Yu, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yu, J. [Univ. of Texas, Arlington, TX (United States); Zhang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-04-03

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

  11. Intermediate energy data

    International Nuclear Information System (INIS)

    Koning, A.J.; Fukahori, T.; Hasegawa, A.

    1998-01-01

    Subgroup 13 (SG13) on Intermediate Energy Nuclear data was formed by NEA Nuclear Science Committee to solve common problems of these types of data for nuclear applications. An overview is presented in this final report of the present activities of SG13, including data needs, high-priority nuclear data request list (nuclides), compilation of experimental data, specialists meetings and benchmarks, data formats and data libraries. Some important accomplishments are summarized, and recommendations are presented. (R.P.)

  12. Bricolage: Re-Discovering History through Intermediality and Performance. A Report on the UCT/CityVarsity Production of "A Day, Across" at the Cape Town Fringe 2014

    Science.gov (United States)

    Muftic, Sanjin

    2016-01-01

    "A Day, Across," performed by the CityVarsity School of Creative Arts at the Cape Town Fringe 2014, was a student production that investigated the link between the youth of South Africa and the centennial of the start of World War I. This paper presents a brief analysis of the rehearsal process as well as certain performance sequences in…

  13. Determination of reaction rate constants for alkylation of 4-(p-nitrobenzyl) pyridine by different alkylating agents.

    Science.gov (United States)

    Walles, S A

    1980-02-01

    The rate constants have been determined for the reaction between some different alkylating agents and 4-(p-nitrobenzyl) pyridine (NBP) in methanol. These constants have been compared with those for alkylation of aniline in water. All the constants were lower in methanol than in water but in different degrees. The rate constants of the different alkylating agents have been calculated at a nucleophilic strength n=2. The genetic risk defined as the degree of alkylation of a nucleophile (n=2) is equivalent to the rate constant kn=2 and the target dose. The dependence of the genetic risk on the rate constant (kn=2) is discussed.

  14. Hydration of urea and alkylated urea derivatives

    Science.gov (United States)

    Kaatze, Udo

    2018-01-01

    Compressibility data and broadband dielectric spectra of aqueous solutions of urea and some of its alkylated derivatives have been evaluated to yield their numbers Nh of hydration water molecules per molecule of solute. Nh values in a broad range of solute concentrations are discussed and are compared to hydration numbers of other relevant molecules and organic ions. Consistent with previous results, it is found that urea differs from other solutes in its unusually small hydration number, corresponding to just one third of the estimated number of nearest neighbor molecules. This remarkable hydration behavior is explained by the large density φH of hydrogen bonding abilities offered by the urea molecule. In terms of currently discussed models of reorientational motions and allied dynamics in water and related associating liquids, the large density φH causes a relaxation time close to that of undisturbed water with most parts of water encircling the solute. Therefore only a small part of disturbed ("hydration") water is left around each urea molecule. Adding alkyl groups to the basic molecule leads to Nh values which, within the series of n-alkylurea derivatives, progressively increase with the number of methyl groups per solute. With n-butylurea, Nh from dielectric spectra, in conformity with many other organic solutes, slightly exceeds the number of nearest neighbors. Compared to such Nh values, hydration numbers from compressibility data are substantially smaller, disclosing incorrect assumptions in the formula commonly used to interpret the experimental compressibilities. Similar to other series of organic solutes, effects of isomerization have been found with alkylated urea derivatives, indicating that factors other than the predominating density φH of hydrogen bond abilities contribute also to the hydration properties.

  15. New Bioactive Alkyl Sulfates from Mediterranean Tunicates

    Directory of Open Access Journals (Sweden)

    Marialuisa Menna

    2012-10-01

    Full Text Available Chemical investigation of two species of marine ascidians, Aplidium elegans and Ciona edwardsii, collected in Mediterranean area, led to isolation of a series of alkyl sulfates (compounds 1–5 including three new molecules 1–3. Structures of the new metabolites have been elucidated by spectroscopic analysis. Based on previously reported cytotoxic activity of these type of molecules, compounds 1–3 have been tested for their effects on the growth of two cell lines, J774A.1 (BALB/c murine macrophages and C6 (rat glioma in vitro. Compounds 1 and 2 induced selective concentration-dependent mortality on J774A.1 cells.

  16. Economic and Environmental Assessment of Switchgrass Production on High-Fertility Soil and an Assessment of Anaerobic Digests as an Intermediate Market for Switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Rhykerd, Robert [Illinois State Univ., Normal, IL (United States); Bierma, Thomas [Illinois State Univ., Normal, IL (United States); Jin, Guang [Illinois State Univ., Normal, IL (United States); Walker, Paul [Illinois State Univ., Normal, IL (United States)

    2014-03-31

    This project had two parts. Part 1 was an economic and environmental assessment of switchgrass production on high-fertility soil, and included an assessment of the effects of field irrigation with treated municipal wastewater (Studies A,C, and E in Final Agreement). Part 2 was an assessment of methods to enhance anaerobic digestion of switchgrass, and included evaluation of several other potential biomass feedstocks (Studies B and D in Final Agreement). Results from Part 1 demonstrated that switchgrass does not compete economically against a corn and soybean rotation on highly productive soils. All four varieties of switchgrass lost money while corn and soybeans were profitable in all four years of this study. Breakeven prices for the four switchgrass varieties were calculated using production costs. The installation of a center pivot irrigation system had minimal impact on crop production and corn and soybean production remained profitable in the year the irrigator was installed. Because of drought and delays in installing the wastewater treatment plant, the irrigation system was not used until year 4 of this study. Therefore, longer term studies evaluating multiple year studies on the impact of irrigation on switchgrass are warranted. Results from irrigating with treated municipal wastewater showed no negative impact on soil quality. Results from Part 2 demonstrated that anaerobic digestion (AD) of switchgrass could be significantly enhanced using low heat (100oC) and mild caustic pretreatment without fine-grinding. Heat for pretreatment could be available from biogas-based combined heat and power (CHP) systems. In bench-top digesters simulating municipal wastewater treatment AD, methane production of coarse-ground switchgrass increased over 20-fold with pretreatment compared to untreated switchgrass. Bench-top studies simulating dairy-based AD also found high specific methane yield, but even untreated switchgrass digested reasonably well, indicating the value of

  17. The intermediate endpoint effect in logistic and probit regression

    Science.gov (United States)

    MacKinnon, DP; Lockwood, CM; Brown, CH; Wang, W; Hoffman, JM

    2010-01-01

    Background An intermediate endpoint is hypothesized to be in the middle of the causal sequence relating an independent variable to a dependent variable. The intermediate variable is also called a surrogate or mediating variable and the corresponding effect is called the mediated, surrogate endpoint, or intermediate endpoint effect. Clinical studies are often designed to change an intermediate or surrogate endpoint and through this intermediate change influence the ultimate endpoint. In many intermediate endpoint clinical studies the dependent variable is binary, and logistic or probit regression is used. Purpose The purpose of this study is to describe a limitation of a widely used approach to assessing intermediate endpoint effects and to propose an alternative method, based on products of coefficients, that yields more accurate results. Methods The intermediate endpoint model for a binary outcome is described for a true binary outcome and for a dichotomization of a latent continuous outcome. Plots of true values and a simulation study are used to evaluate the different methods. Results Distorted estimates of the intermediate endpoint effect and incorrect conclusions can result from the application of widely used methods to assess the intermediate endpoint effect. The same problem occurs for the proportion of an effect explained by an intermediate endpoint, which has been suggested as a useful measure for identifying intermediate endpoints. A solution to this problem is given based on the relationship between latent variable modeling and logistic or probit regression. Limitations More complicated intermediate variable models are not addressed in the study, although the methods described in the article can be extended to these more complicated models. Conclusions Researchers are encouraged to use an intermediate endpoint method based on the product of regression coefficients. A common method based on difference in coefficient methods can lead to distorted

  18. Observations on transverse moments of pions neutral and gamma rays of intermediate mass state ∼3GeW/c2 (MIRIM) in meson multiple production

    International Nuclear Information System (INIS)

    Fauth, A.C.

    1986-01-01

    The transverse moment distribution of pions neutral of 32 mirin c-jets with ΣΕγ>20 TeV by tw methods of 2γ->Π 0 coupling. This results independ of any particle production model. A simulation of pion production by Monte Carlo method is carried out and it is shown that, the two methods provide to obtain approximately 50% of correct couplings. The form of pions neutral distribution depends weakly of the percentage of correct couplings. The pions neutral transverse moment distribution of Mirins events is obtained by a third model which is completely independent from the two first, which consists in a composition between an analytical solution and the Monte Carlo method. The results of the three methods are consistents among themselves. (M.C.K.) [pt

  19. Relativistic Landau-Vlasov equations for hadronic matter and medium effect in the pion production in intermediate-energy heavy ion reactions

    International Nuclear Information System (INIS)

    Cubero, M.

    1990-08-01

    The present thesis deals with the medium effects, which occur both in the mean-field contributions and in the collisional term. As example medium effects in the production of pions in heavy ion reactions are studied. First an extended version of quantum hadrodynamics is introduced, which contains two baryon fields and three meson fields. Then the Keldysh formalism is explained, by which the Dyson equations for nonequilibrium systems can be derived. These Kadanoff-Baym equations are explicitely given for fermions (nucleons and deltas) and bosons (pions). Thereafter three coupled Landau-Vlasov equations for nucleons, deltas, and pions are derived from the Kadanoff-Baym equations by means of the gradient expansion and the quasi-particle approximation. Finally these three relativistic Landau-Vlasov equations are used to study the influence of the expansion of the fireball on the pion production in heavy ion collisions. (orig./HSI) [de

  20. Benchmark of European strategies of development of gas production and valorisation sectors. European inventory and synthetic sheets per country - Intermediate report

    International Nuclear Information System (INIS)

    Bastide, Guillaume

    2014-10-01

    After a European inventory and a discussion of the evolution of the number of methanization installations, of the evolution of biogas production, and of the situation and main economic levers in European countries, this report proposes sheets of data and analysis for Germany, Italy, Netherlands, the United Kingdom, and Sweden. For each of these countries, the document proposes an historical overview and some key figures on various aspects (types and number of installations, biogas production and valorisation, resources and processed quantities, technologies, digestates, costs of installation and financing modes, jobs and enterprises in the sector), a comment of the national strategy (actors, strategy regarding renewable energy, climate protection and waste processing, regulatory and financial incentive measures, regulatory context and administrative management), and perspectives (maximum potential, development perspectives)

  1. Contemporary Presence of Dynamical and Statistical Intermediate Mass Fragment Production Mechanisms in Midperipheral NI+NI Collisions at 30 MeV/nucleon

    Science.gov (United States)

    Milazzo, P. M.; Sisto, M.; Margagliotti, G. V.; Rui, R.; Vannini, G.; Bruno, M.; D'Agostino, M.; Colonna, N.; Agodi, C.; Alba, R.; Bellia, G.; Colonna, M.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Maiolino, C.; Migneco, E.; Piattelli, P.; Santonocito, D.; Sapienza, P.; Gramegna, F.; Mastinu, P. F.; Fabbietti, L.; Iori, I.; Moroni, A.; Belkacem, M.

    2001-11-01

    The 58Ni+58Ni reaction at 30 MeV/nucleon has been experimentally investigated at the Superconducting Cyclotron of the INFN Laboratori Nazionali del Sud. In midperipheral collisions the production of massive fragments (4 ≤ Z ≤ 12), consistent with the statistical fragmentation of the projectile-like residue and the contemporary dynamical fragmentation of a neck, joining projectile-like and target-like residues, has been observed.

  2. Ring positional differentiation of isomeric N-alkylated fluorocathinones by gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Westphal, Folker; Junge, Thomas

    2012-11-30

    In analogy to our previously published procedure for the differentiation of regioisomeric fluoroamphetamines a method was developed, to differentiate ring positional isomeric fluorocathinones by product ion spectrometry of ions generated by chemical ionization (CI) under GC-MS conditions using methane as reagent gas. N-alkylated ortho-, meta- and para-fluorocathinones could be unequivocally differentiated by product ion spectrometry of the hydrogen fluoride loss ions [M+H-HF](+) using a triple quadrupole mass spectrometer with argon as collision gas under normalized collision conditions. This method enables the differentiation of ring positional isomers of fluorocathinones even in complex mixtures and low concentrations. The applicability of the method was shown by the analysis of synthesized N-alkylated ortho-, meta- and para-fluorocathinones and seized designer drug mixtures. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. High octane gasoline components from catalytic cracking gasoline, propylene, and isobutane by disproportionation, clevage and alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Banks, R.

    1980-07-08

    A process is described for producing high octane value gasoline which comprises in a disproportionation zone subjecting propylene and a mixture of propylene and ethylene obtained as hereinafter delineated to disproportionation conditions to produce a stream containing ethylene and a stream containing butenes, passing the ethylene-containing stream from said disproportionation zone together with a catalytic cracking gasoline to a cleavage zone under disproportionation conditions and subjecting the mixture of hydrocarbons therin to cleavage to produce said mixture of propylene and ethylene, a C/sub 5//sup +/ gasoline-containing product and butenes and wherein the butenes obtained in the overall operation of the disproportionation zone and the cleavage zone are passed to an alkylation zone wherein said butenes are used to alkylate an isoparaffin to produce additional high octane value product.

  4. Localization of adenovirus morphogenesis players, together with visualization of assembly intermediates and failed products, favor a model where assembly and packaging occur concurrently at the periphery of the replication center.

    Directory of Open Access Journals (Sweden)

    Gabriela N Condezo

    2017-04-01

    Full Text Available Adenovirus (AdV morphogenesis is a complex process, many aspects of which remain unclear. In particular, it is not settled where in the nucleus assembly and packaging occur, and whether these processes occur in a sequential or a concerted manner. Here we use immunofluorescence and immunoelectron microscopy (immunoEM to trace packaging factors and structural proteins at late times post infection by either wildtype virus or a delayed packaging mutant. We show that representatives of all assembly factors are present in the previously recognized peripheral replicative zone, which therefore is the AdV assembly factory. Assembly intermediates and abortive products observed in this region favor a concurrent assembly and packaging model comprising two pathways, one for capsid proteins and another one for core components. Only when both pathways are coupled by correct interaction between packaging proteins and the genome is the viral particle produced. Decoupling generates accumulation of empty capsids and unpackaged cores.

  5. Localization of adenovirus morphogenesis players, together with visualization of assembly intermediates and failed products, favor a model where assembly and packaging occur concurrently at the periphery of the replication center.

    Science.gov (United States)

    Condezo, Gabriela N; San Martín, Carmen

    2017-04-01

    Adenovirus (AdV) morphogenesis is a complex process, many aspects of which remain unclear. In particular, it is not settled where in the nucleus assembly and packaging occur, and whether these processes occur in a sequential or a concerted manner. Here we use immunofluorescence and immunoelectron microscopy (immunoEM) to trace packaging factors and structural proteins at late times post infection by either wildtype virus or a delayed packaging mutant. We show that representatives of all assembly factors are present in the previously recognized peripheral replicative zone, which therefore is the AdV assembly factory. Assembly intermediates and abortive products observed in this region favor a concurrent assembly and packaging model comprising two pathways, one for capsid proteins and another one for core components. Only when both pathways are coupled by correct interaction between packaging proteins and the genome is the viral particle produced. Decoupling generates accumulation of empty capsids and unpackaged cores.

  6. Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases.

    Science.gov (United States)

    McNeill, Luke A; Brown, Toby J N; Sami, Malkit; Clifton, Ian J; Burzlaff, Nicolai I; Claridge, Timothy D W; Adlington, Robert M; Baldwin, Jack E; Rutledge, Peter J; Schofield, Christopher J

    2017-09-18

    Isopenicillin N synthase (IPNS) catalyses the four-electron oxidation of a tripeptide, l-δ-(α-aminoadipoyl)-l-cysteinyl-d-valine (ACV), to give isopenicillin N (IPN), the first-formed β-lactam in penicillin and cephalosporin biosynthesis. IPNS catalysis is dependent upon an iron(II) cofactor and oxygen as a co-substrate. In the absence of substrate, the carbonyl oxygen of the side-chain amide of the penultimate residue, Gln330, co-ordinates to the active-site metal iron. Substrate binding ablates the interaction between Gln330 and the metal, triggering rearrangement of seven C-terminal residues, which move to take up a conformation that extends the final α-helix and encloses ACV in the active site. Mutagenesis studies are reported, which probe the role of the C-terminal and other aspects of the substrate binding pocket in IPNS. The hydrophobic nature of amino acid side-chains around the ACV binding pocket is important in catalysis. Deletion of seven C-terminal residues exposes the active site and leads to formation of a new type of thiol oxidation product. The isolated product is shown by LC-MS and NMR analyses to be the ene-thiol tautomer of a dithioester, made up from two molecules of ACV linked between the thiol sulfur of one tripeptide and the oxidised cysteinyl β-carbon of the other. A mechanism for its formation is proposed, supported by an X-ray crystal structure, which shows the substrate ACV bound at the active site, its cysteinyl β-carbon exposed to attack by a second molecule of substrate, adjacent. Formation of this product constitutes a new mode of reaction for IPNS and non-heme iron oxidases in general. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  7. Intermediate mass fragment production from neck-like structures in peripheral 58Ni + 58Ni collisions at E/A = 30 MeV

    International Nuclear Information System (INIS)

    Milazzo, P.M.; Sisto, M.; Vannini, G.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Colonna, N.; Fabbietti, L.

    2000-01-01

    An experiment to investigate the 58 Ni + 58 Ni reaction at E/A = 30 MeV was performed at the Superconducting Cyclotron of the INFN Laboratorio Nazionale del Sud. In peripheral collisions massive fragments (4 ≤ Z ≤ 12) emission from neck-like structures joining projectile-like and target-like residues has been observed in coincidence with other reaction products. Their emission patterns exhibit features consistent with dynamical fragmentation of a neck zone between the interacting nuclei. In addition, at the same time the projectile-like and target-like residues are subject to statistical decay. (author)

  8. Direct, Regioselective N-Alkylation of 1,3-Azoles.

    Science.gov (United States)

    Chen, Shuai; Graceffa, Russell F; Boezio, Alessandro A

    2016-01-04

    Regioselective N-alkylation of 1,3-azoles is a valuable transformation. Organomagnesium reagents were discovered to be competent bases to affect regioselective alkylation of various 1,3-azoles. Counterintuitively, substitution selectively occurred at the more sterically hindered nitrogen atom. Numerous examples are provided, on varying 1,3-azole scaffolds, with yields ranging from 25 to 95%.

  9. Polyfluorinated alkyl phosphate ester surfactants - current knowledge and knowledge gaps

    DEFF Research Database (Denmark)

    Taxvig, Camilla; Rosenmai, Anna Kjerstine; Vinggaard, Anne Marie

    2014-01-01

    information on fluorochemicals. Polyfluorinated alkyl phosphate ester surfactants (PAPs) belong to the group of polyfluorinated alkyl surfactants. They have been detected in indoor dust and are widely used in food-contact materials, from which they have the ability to migrate into food. Toxicological data...

  10. dialkylated perylene diimides in poly(alkyl methacrylate) films.

    Indian Academy of Sciences (India)

    lene diimides in films of poly(alkyl methacrylate)s (PAMAs) with 5 different alkyl groups and in a 'model solvent' ... indicate that the perylenes can be used as a complementary probe of local polymer chain dynamics, but they are ... can be designed to allow a greater or lesser interaction with an anisotropic host matrix. Also ...

  11. Organocalcium-mediated nucleophilic alkylation of benzene.

    Science.gov (United States)

    Wilson, Andrew S S; Hill, Michael S; Mahon, Mary F; Dinoi, Chiara; Maron, Laurent

    2017-12-01

    The electrophilic aromatic substitution of a C-H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich π-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n -alkyl derivatives-synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride-react with protio and deutero benzene at 60°C through nucleophilic substitution of an aromatic C-D/H bond. These reactions produce the n- alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C-H activation transition state. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  12. Alkylation of pyridines at their 4-positions with styrenes plus yttrium reagent or benzyl Grignard reagents.

    Science.gov (United States)

    Mizumori, Tomoya; Hata, Takeshi; Urabe, Hirokazu

    2015-01-02

    A new regioselective alkylation of pyridines at their 4-position was achieved with styrenes in the presence of yttrium trichloride, BuLi, and diisobutylaluminium hydride (DIBAL-H) in THF. Alternatively, similar products were more simply prepared from pyridines and benzyl Grignard reagents. These reactions are not only a useful preparation of 4-substituted pyridines but are also complementary to other relevant reactions usually giving 2-substituted pyridines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Isobutane/2-butene alkylation with zeolite Y without BrÆnsted acidity

    OpenAIRE

    Rosenbach Jr,Nilton; Mota,Claudio J. A.

    2005-01-01

    Alkylation of isobutane with 2-butene was performed on metal-exchanged Y zeolites, using an alkylchloride as carbocation initiator. The results indicated that, compared with a protonic zeolite, the deactivation was significantly slower and the production of trimethylpentanes was higher on the metal-exchanged zeolites. The metal cations act as Lewis acids, interacting with the chloride initiating the carbocationic reactions. The results also support the view that protonic sites on the catalyst...

  14. Addition of potassium carbonate to continuous cultures of mixed ruminal bacteria shifts volatile fatty acids and daily production of biohydrogenation intermediates.

    Science.gov (United States)

    Jenkins, T C; Bridges, W C; Harrison, J H; Young, K M

    2014-02-01

    A recent study reported a 0.4 percentage unit increase in milk fat of lactating dairy cattle when dietary K was increased from 1.2 to 2% with potassium carbonate. Because milk fat yield has been associated with ruminal production of certain conjugated linoleic acid (CLA) isomers, 2 studies were conducted to determine if increasing potassium carbonate in the rumen would alter patterns of fermentation and biohydrogenation. In experiment 1, 5 dual-flow continuous fermenters were injected just before each feeding with a 10% (wt/wt) stock potassium carbonate solution to provide the equivalent of 1.1 (K1), 2.2 (K2), and 3.3 (K3) % of diet dry matter (DM) as added K. One of the remaining fermenters received no K (K0) and the last fermenter (NaOH) was injected with adequate NaOH stock solution (10%, wt/wt) to match the pH observed for the K3 treatment. For experiment 2, 6 dual-flow continuous fermenters were used to evaluate 6 treatments arranged in a 2 × 3 factorial to examine 2 levels of soybean oil (0 and 3.64% of diet DM) and added K at 0, 1.6, and 3.3% of diet DM. In both experiments, fermenters were fed 55 to 57 g of DM/d of a typical dairy diet consisting of 1:1 forage (10% alfalfa hay and 90% corn silage) to concentrate mix in 2 equal portions at 0800 and 1630 h, and fed the respective diets for 10-d periods. Potassium carbonate addition increased pH in both experiments. Acetate:propionate ratio and pH in experiment 1 increased linearly for K0 to K3. Acetate:propionate ratio was lower for NaOH compared with K3 but the pH was the same. The trans-11 18:1 and cis-9,trans-11 CLA production rates (mg/d) increased linearly from K0 to K3, but K3 and NaOH did not differ. Production of trans-10 18:1 decreased and that of trans-10,cis-12 tended to decrease from K0 to K3, but production of trans-10,cis-12 CLA remained high for NaOH. Addition of K to the cultures in experiment 2 decreased propionate and increased acetate and acetate:propionate ratio for the 0% fat diet but

  15. Nanostructured poly(benzimidazole membranes by N-alkylation

    Directory of Open Access Journals (Sweden)

    J. Weber

    2014-01-01

    Full Text Available Modification of poly(benzimidazole (PBI by N-alkylation leads to polymers capable of undergoing microphase separation. Polymers with different amounts of C18 alkyl chains have been prepared. The polymers were analyzed by spectroscopy, thermal analysis, electron microscopy and X-ray scattering. The impact of the amount of alkyl chains on the observed microphase separation was analyzed. Membranes prepared from the polymers do show microphase separation, as evidenced by scattering experiments. While no clear morphology could be derived for the domains in the native state, evidence for the formation of lamellar morphologies upon doping with phosphoric acid is provided. Finally, the proton conductivity of alkyl-modified PBI is compared with that of pure PBI, showing that the introduction of alkyl side chains does not result in significant conductivity changes.

  16. Parp1 protects against Aag-dependent alkylation-induced nephrotoxicity in a sex-dependent manner.

    Science.gov (United States)

    Calvo, Jennifer A; Allocca, Mariacarmela; Fake, Kimberly R; Muthupalani, Sureshkumar; Corrigan, Joshua J; Bronson, Roderick T; Samson, Leona D

    2016-07-19

    Nephrotoxicity is a common toxic side-effect of chemotherapeutic alkylating agents. Although the base excision repair (BER) pathway is essential in repairing DNA alkylation damage, under certain conditions the initiation of BER produces toxic repair intermediates that damage healthy tissues. We have shown that the alkyladenine DNA glycosylase, Aag (a.k.a. Mpg), an enzyme that initiates BER, mediates alkylation-induced whole-animal lethality and cytotoxicity in the pancreas, spleen, retina, and cerebellum, but not in the kidney. Cytotoxicity in both wild-type and Aag-transgenic mice (AagTg) was abrogated in the absence of Poly(ADP-ribose) polymerase-1 (Parp1). Here we report that Parp1-deficient mice expressing increased Aag (AagTg/Parp1-/-) develop sex-dependent kidney failure upon exposure to the alkylating agent, methyl methanesulfonate (MMS), and suffer increased whole-animal lethality compared to AagTg and wild-type mice. Macroscopic, histological, electron microscopic and immunohistochemical analyses revealed morphological kidney damage including dilated tubules, proteinaceous casts, vacuolation, collapse of the glomerular tuft, and deterioration of podocyte structure. Moreover, mice exhibited clinical signs of kidney disease indicating functional damage, including elevated blood nitrogen urea and creatinine, hypoproteinemia and proteinuria. Pharmacological Parp inhibition in AagTg mice also resulted in sensitivity to MMS-induced nephrotoxicity. These findings provide in vivo evidence that Parp1 modulates Aag-dependent MMS-induced nephrotoxicity in a sex-dependent manner and highlight the critical roles that Aag-initiated BER and Parp1 may play in determining the side-effects of chemotherapeutic alkylating agents.

  17. CC-1065 and the duocarmycins: unraveling the keys to a new class of naturally derived DNA alkylating agents.

    Science.gov (United States)

    Boger, D L; Johnson, D S

    1995-01-01

    Key studies defining the DNA alkylation properties and selectivity of a new class of exceptionally potent, naturally occurring antitumor antibiotics including CC-1065, duocarmycin A, and duocarmycin SA are reviewed. Recent studies conducted with synthetic agents containing deep-seated structural changes and the unnatural enantiomers of the natural products and related analogs have defined the structural basis for the sequence-selective alkylation of duplex DNA and fundamental relationships between chemical structure, functional reactivity, and biological properties. The agents undergo a reversible, stereoelectronically controlled adenine-N3 addition to the least substituted carbon of the activated cyclopropane within selected AT-rich sites. The preferential AT-rich non-covalent binding selectivity of the agents within the narrower, deeper AT-rich minor groove and the steric accessibility to the alkylation site that accompanies deep AT-rich minor groove penetration control the sequence-selective DNA alkylation reaction and stabilize the resulting adduct. For the agents that possess sufficient reactivity to alkylate DNA, a direct relationship between chemical or functional stability and biological potency has been defined. Images Fig. 1 Fig. 2 PMID:7731958

  18. DNA Polymerase α (swi7) and the Flap Endonuclease Fen1 (rad2) Act Together in the S-Phase Alkylation Damage Response in S. pombe

    Science.gov (United States)

    Koulintchenko, Milana; Vengrova, Sonya; Eydmann, Trevor; Arumugam, Prakash; Dalgaard, Jacob Z.

    2012-01-01

    Polymerase α is an essential enzyme mainly mediating Okazaki fragment synthesis during lagging strand replication. A specific point mutation in Schizosaccharomyces pombe polymerase α named swi7-1, abolishes imprinting required for mating-type switching. Here we investigate whether this mutation confers any genome-wide defects. We show that the swi7-1 mutation renders cells hypersensitive to the DNA damaging agents methyl methansulfonate (MMS), hydroxyurea (HU) and UV and incapacitates activation of the intra-S checkpoint in response to DNA damage. In addition we show that, in the swi7-1 background, cells are characterized by an elevated level of repair foci and recombination, indicative of increased genetic instability. Furthermore, we detect novel Swi1-, -Swi3- and Pol α- dependent alkylation damage repair intermediates with mobility on 2D-gel that suggests presence of single-stranded regions. Genetic interaction studies showed that the flap endonuclease Fen1 works in the same pathway as Pol α in terms of alkylation damage response. Fen1 was also required for formation of alkylation- damage specific repair intermediates. We propose a model to explain how Pol α, Swi1, Swi3 and Fen1 might act together to detect and repair alkylation damage during S-phase. PMID:23071723

  19. Cu(I)-Catalyzed Enantioselective Friedel-Crafts Alkylation of Indoles with 2-Aryl-N-sulfonylaziridines as Alkylating Agents.

    Science.gov (United States)

    Ge, Chen; Liu, Ren-Rong; Gao, Jian-Rong; Jia, Yi-Xia

    2016-07-01

    A highly enantioselective Friedel-Crafts alkylation of indoles with N-sulfonylaziridines as alkylating agents has been developed by utilizing the complex of Cu(CH3CN)4BF4/(S)-Segphos as a catalyst. A range of optically active tryptamine derivatives are obtained in good to excellent yields and enantioselectivities (up to >99% ee) via a kinetic resolution process.

  20. Sequential One-Pot Ruthenium-Catalyzed Azide−Alkyne Cycloaddition from Primary Alkyl Halides and Sodium Azide

    KAUST Repository

    Johansson, Johan R.

    2011-04-01

    An experimentally simple sequential one-pot RuAAC reaction, affording 1,5-disubstituted 1H-1,2,3-triazoles in good to excellent yields starting from an alkyl halide, sodium azide, and an alkyne, is reported. The organic azide is formed in situ by treating the primary alkyl halide with sodium azide in DMA under microwave heating. Subsequent addition of [RuClCp*(PPh 3) 2] and the alkyne yielded the desired cycloaddition product after further microwave irradiation. © 2011 American Chemical Society.

  1. Surface reactivity and in vitro toxicity on human bronchial epithelial cells (BEAS-2B) of nanomaterials intermediates of the production of titania-based composites.

    Science.gov (United States)

    Vergaro, Viviana; Aldieri, Elisabetta; Fenoglio, Ivana; Marucco, Arianna; Carlucci, Claudia; Ciccarella, Giuseppe

    2016-08-01

    Titanium dioxide (TiO2) nanoparticles (NPs) are manufactured worldwide in large quantities for use in a wide range of applications. Evaluating the hazards associated with TiO2 NPs is crucial as it enables risk assessment related to human and environmental exposure. In this study the in vitro human toxicity of a set of TiO2 NPs modified with acetic, oleic and boric acids were studied in order to assess the hazard in view of a future scale-up of the synthesis. The surface reactivity of the powders under simulated solar illumination and in the dark has been evaluated by means of EPR spectroscopy. Human bronchial epithelial cells (BEAS-2B) have been chosen as a model for lung epithelium. Cytotoxicity has been assessed by measuring the cells membrane integrity by lactate dehydrogenase (LDH) assay, and the inflammatory response evaluated as nitric oxide (NO) and TNF-α production, and oxidative stress measured as intracellular reduced glutathione (GSH) levels, and induced lipoperoxidation. Aeroxide P25 was used for comparison. The results demonstrated a low photoreactivity and toxic effects lower than Aeroxide P25 of the nano-TiO2 powders, probably as a consequence of the presence of acidic moieties at the surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. An ethnic-specific polymorphism in the catalytic subunit of glutamate-cysteine ligase impairs the production of glutathione intermediates in vitro.

    Science.gov (United States)

    Le, Truc M; Willis, Alecia S; Barr, Frederick E; Cunningham, Gary R; Canter, Jeffrey A; Owens, Sarah E; Apple, Rachel K; Ayodo, George; Reich, David; Summar, Marshall L

    2010-09-01

    Glutathione plays a crucial role in free radical scavenging, oxidative injury, and cellular homeostasis. Previously, we identified a non-synonymous polymorphism (P462S) in the gene encoding the catalytic subunit of glutamate-cysteine ligase (GCLC), the rate-limiting enzyme in glutathione biosynthesis. This polymorphism is present only in individuals of African descent. Presently, we report that this ethnic-specific polymorphism (462S) encodes an enzyme with significantly decreased in vitro activity when expressed by either a bacterial or mammalian cell expression system. In addition, overexpression of the 462P wild-type GCLC enzyme results in higher intracellular glutathione concentrations than overexpression of the 462S isoform. We also demonstrate that apoptotically stimulated mammalian cells overexpressing the 462S enzyme have increased caspase activation and increased DNA laddering compared to cells overexpressing the wild-type 462P enzyme. Finally, we genotyped several African and African-descent populations and demonstrate that the 462S polymorphism is in Hardy-Weinberg disequilibrium, with no individuals homozygous for the 462S polymorphism identified. These findings describe a glutathione production pathway polymorphism present in individuals of African descent with significantly decreased in vitro activity.

  3. Light intensity impacts the production of biofuel intermediates in Heterosigma akashiwo growing on simulated flue gas containing carbon dioxide and nitric oxide.

    Science.gov (United States)

    Bianco, Colleen M; Stewart, Jennifer J; Miller, Katherine R; Fitzgerald, Catherine; Coyne, Kathryn J

    2016-11-01

    As a potential biofuel feedstock, the marine microalga, Heterosigma akashiwo, accumulates significant lipids, is capable of long-term growth in outdoor photobioreactors, and is an excellent candidate for the bioremediation of industrial emissions. Here, we evaluated resource partitioning in H. akashiwo growing on a CO2 and NO gas mixture under three light intensities: 160, 560, or 1200μmolquantam(-2)s(-1). Light levels had no effect on growth; however, cultures in high light accumulated 2.3-fold more carbohydrates and 17% fewer lipids. Light levels did not affect the percentage of saturated fatty acids, but mono-unsaturates increased by 6% and poly-unsaturates decreased by 12% in high light. The fatty acid profiles reported here suggest that H. akashiwo is a good candidate for the production of neutral lipids for biodiesel and also omega-3 fatty acids, and that the quality of biodiesel acquired from feedstocks grown under fluctuating light conditions would be relatively stable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Form-stable crystalline polymer pellets for thermal energy storage: high density polyethylene intermediate products. Final report, October 1, 1977--January 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Botham, R.A.; Ball, G.L. III; Jenkins, G.H.; Salyer, I.O.

    1978-01-01

    The primary objectives of this program were to demonstrate: (1) that form-stable high density polyethylene (HDPE), which has been shown to have desirable properties as a phase-change type of thermal energy storage material, could be produced by processing in a polyethylene plant for a projected price near 26 cents/lb; and (2) that the raw material, ethylene, will be available in the very long-term from alternate sources (other than petroleum and natural gas). These objectives were accomplished. Production of useful, form-stable HDPE pellets by radiation cross-linking was demonstrated. Such pellets are estimated to be obtainable at 26 cents/lb, using large-volume (> or equal to 10,000,000 lb/yr) in-plant processing. Well-developed technologies exist for obtaining ethylene from coal and plant (or biomass) sources, thus assuring its long-term availability and therefore that of polyethylene. A cost-benefit analysis of the HDPE thermal energy storage system was conducted over its 120 to 140/sup 0/C optimum operating range which is most suited for absorption air conditioning. The HDPE is more cost effective than either rocks, ethylene glycol, or pressurized water and is even competitive with a hypothetical 5 cents/lb salt-hydrate melting in this temperature range. These results applied, as appropriate, to both air and liquid transfer systems.

  5. The crystal structure of an intermediate dimer of aspergilloglutamic peptidase that mimics the enzyme-activation product complex produced upon autoproteolysis.

    Science.gov (United States)

    Sasaki, Hiroshi; Kubota, Keiko; Lee, Woo C; Ohtsuka, Jun; Kojima, Masaki; Iwata, So; Nakagawa, Atsushi; Takahashi, Kenji; Tanokura, Masaru

    2012-07-01

    Aspergilloglutamic peptidase from Aspergillus niger var. macrosporus (AGP) is one of the so-called pepstatin-insensitive acid endopeptidases, which are distinct from the well-studied aspartic peptidases. Among the known homologues of the glutamic peptidases, AGP is a unique two-chain enzyme with a light chain and a heavy chain bound non-covalently with each other, and thus is an interesting target for protein structure-function relationship studies. In this article, we report the crystal structure of a dimeric form of the enzyme at a resolution of 1.6 Å. This form has a unique structure in which the C-terminal region of the light chain of one of the molecules binds to the active site cleft of the other molecule like a part of a substrate. This form mimics the enzyme-activation product complex produced upon autoproteolysis, and provides a structural clue that could help to clarify the activation mechanism. This type of dimeric structure of a peptidase is here reported for the first time.

  6. Synthesis of optically active bifunctional building blocks through enantioselective copper-catalyzed allylic alkylation using Grignard reagents

    NARCIS (Netherlands)

    van Zijl, Anthoni W.; Lopez, Fernando; Minnaard, Adriaan J.; Feringa, Ben L.

    2007-01-01

    Enantioselective copper-catalyzed allylic alkylations were performed on allylic bromides with a protected hydroxyl or amine functional group using several Grignard reagents and Taniaphos L1 as a ligand. The terminal olefin moiety in the products was transformed into various functional groups without

  7. Asymmetric Synthesis of (-)-Incarvillateine Employing an Intramolecular Alkylation via Rh-Catalyzed Olefinic C-H Bond Activation

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Andy; Bergman, Robert; Ellman, Jonathan

    2008-02-18

    An asymmetric total synthesis of (-)-incarvillateine, a natural product having potent analgesic properties, has been achieved in 11 steps and 15.4% overall yield. The key step is a rhodium-catalyzed intramolecular alkylation of an olefinic C-H bond to set two stereocenters. Additionally, this transformation produces an exocyclic, tetrasubstituted alkene through which the bicyclic piperidine moiety can readily be accessed.

  8. Perfluorinated alkylated substances (PFAS) in the European Nordic environment

    Energy Technology Data Exchange (ETDEWEB)

    Berger, U. [Norwegian Institute of Air Research (NILU), Tromso (Norway); Jaernberg, U. [Institute of Applied Environmental Research (ITM), Stockholm (Sweden); Kallenborn, R. [Norwegian Institute of Air Research (NILU), Kjeller (Norway)

    2004-09-15

    Perfluorinated alkylated substances (PFAS) have been industrially produced for several decades and are applied as stain and water repellents for surface treatment of textiles, carpets, leather and paper products. Perfluorooctane sulfonate (PFOS), a degradation product of several PFAS, has recently gained considerable attention because of its ubiquitous distribution in the environment and its presence in human blood plasma. Though most of the production volume of PFOS-based chemicals has been voluntarily phased out by the manufacturers, similar compounds with perfluorinated chains, including perfluorinated carboxylic acids, continue to be employed for comparable applications. A first screening project on the distribution of PFAS in the environment of five Nordic countries was supported and financed by the Nordic Council of Ministers through the Chemicals Group and the Environmental Monitoring Group and national institutions. The aim of the study was to assess the levels and distribution of PFAS in the Nordic environment and to trace differences in contaminant concentrations and patterns between different countries and types of matrices.

  9. Opinion of the Scientific Committee on Consumer Safety (SCCS) - Revision of the opinion on the safety of the use of Silica, Hydrated Silica, and Silica Surface Modified with Alkyl Silylates (nano form) in cosmetic products.

    Science.gov (United States)

    Sccs; Hoet, P H M

    2016-02-01

    The SCCS has concluded that the evidence, both provided in the submission and that available in scientific literature, is inadequate and insufficient to allow drawing any firm conclusion either for or against the safety of any of the individual SAS material, or any of the SAS categories that are intended for use in cosmetic products. As the SCCS has not been able to conclude on the safety of the synthetic amorphous silica (SAS) materials included in the current submission, the Applicant is advised to follow the SCCS Guidance on Risk Assessment of Nanomaterials (SCCS/1484/12). A brief summary is provided to enable/facilitate future evaluation of the SAS materials in cosmetic products. Copyright © 2015. Published by Elsevier Inc.

  10. Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with Fe-based Bimetallic Supported Catalysts

    DEFF Research Database (Denmark)

    Khokarale, Santosh Govind; He, Jian; Schill, Leonhard

    2018-01-01

    significantly when using Fe-Ni/ZrO2 instead of Fe/ZrO2 alone. Moreover, the ZrO2 support contributed to improve the yield as a phase transition of ZrO2 from tetragonal to monoclinic occurred after metal doping giving rise to fine dispersion of the Fe and Ni on the ZrO2 , resulting in a higher catalytic activity...... of the material. Interestingly, it was observed that Fe-Ni/ZrO2 also effectively catalyzed methanol reforming to produce H2 in situ, followed by HDO of ML, yielding 60 % MP at 220 °C with 50 bar N2 instead of H2. Fe-Ni/ZrO2 also catalyzed HDO of other short-chain alkyl lactates to the corresponding alkyl...

  11. Catalysis in the alkylation reaction of 1-naphthol with epichlorohydrin

    Directory of Open Access Journals (Sweden)

    SLOBODANKA JOVANOVIC

    2006-09-01

    Full Text Available Two new and improved procedures were developed for the synthesis of 1-(1-naphthyloxy-2,3-epoxypropane as an important intermediate in the production of the beta-blocker and antioxidant, 1-[(1-methylethylamino]-3-(1-naphthyloxy-2-propanol (propranolol. Both base homogeneous and heterogeneous PTC catalysis were employed. High yields and remarkable selectivity were achieved. The improved purity is particularly important, in view of the quality requirements for propranolol hydrochloride as an active pharmaceutical ingredient.

  12. O-alkylation in DNA does not correlate with the formation of chromosome breakage events in D. melanogaster.

    Science.gov (United States)

    Vogel, E W

    1986-09-01

    Postmeiotic cell stages of repair-proficient ring-X (RX) males were treated with methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), diethylnitrosamine (DEN) or ethylnitrosourea (ENU) and then mated to either repair-defective (mei-9L1) or to repair-competent females (mei-9+). Absence of the mei-9+ function resulted in a hypermutability effect to all alkylating agents (AAs) when they were assayed for their ability to induce chromosomal aberrations (chromosome loss; CL), irrespective of marked differences in distribution of DNA adducts brought about by these AAs. This picture is different from that described previously for the induction of point mutations (Vogel et al., 1985a). There, evidence was presented indicating that reduction in DNA excision repair does not affect point mutation induction (recessive lethals) by those AAs most efficient in ring-oxygen alkylation such as ENU, DEN, N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), and isopropyl methanesulfonate (iPMS): the order of hypermutability of AAs with mei-9L relative to mei-9+ was MMS greater than MNU greater than DMN = EMS greater than iPMS = ENU = DEN = ENNG. When the percentage of lethal mutations induced in mei-9L1 females were plotted against those determined for mei-9+ females, straight lines of following slopes were obtained: MMS = 7.6, MNU = 5.4, DMN = 2.4, EMS = 2.4, and iPMS = ENU = DEN = ENNG = 1. Those findings, together with the recent observation that AAs do not split into two groups when assayed for their ability to cause CL, point to the involvement of different DNA alkylation products in ENU- and DEN-induced chromosome loss vs. that of point mutations. It is concluded that with ENU and DEN chromosomal loss results from N-alkylation products whereas point mutations (SLRL) are the consequence of interactions with oxygen-sites in DNA. Thus, as a consequence of a very dominating role of O-ethylguanine (and possibly O4-alkylation of thymine), N-alkylation in DNA does not contribute

  13. Bacterial intermediate filaments

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Cabeen, M.; Jacobs-Wagner, C.

    2009-01-01

    Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin...... also shares in vivo properties of assembly and dynamics with IF proteins by forming stable filamentous structures that continuously incorporate subunits along their length and that grow in a nonpolar fashion. De novo assembly of crescentin is biphasic and involves a cell size-dependent mechanism...... a new function for MreB and providing a parallel to the role of actin in IF assembly and organization in metazoan cells. Additionally, analysis of an MreB localization mutant suggests that cell wall insertion during cell elongation normally occurs along two helices of opposite handedness, each...

  14. Alkylation of Staurosporine to Derive a Kinase Probe for Fluorescence Applications.

    Science.gov (United States)

    Disney, Alexander J M; Kellam, Barrie; Dekker, Lodewijk V

    2016-05-06

    The natural product staurosporine is a high-affinity inhibitor of nearly all mammalian protein kinases. The labelling of staurosporine has proven effective as a means of generating protein kinase research tools. Most tools have been generated by acylation of the 4'-methylamine of the sugar moiety of staurosporine. Herein we describe the alkylation of this group as a first step to generate a fluorescently labelled staurosporine. Following alkylation, a polyethylene glycol linker was installed, allowing subsequent attachment of fluorescein. We report that this fluorescein-staurosporine conjugate binds to cAMP-dependent protein kinase in the nanomolar range. Furthermore, its binding can be antagonised with unmodified staurosporine as well as ATP, indicating it targets the ATP binding site in a similar fashion to native staurosporine. This reagent has potential application as a screening tool for protein kinases of interest. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  15. Tools to discover anionic and nonionic polyfluorinated alkyl surfactants by liquid chromatography electrospray ionisation mass spectrometry

    DEFF Research Database (Denmark)

    Trier, Xenia; Granby, Kit; Christensen, Jan H.

    2011-01-01

    A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC–ESI−–QTOF–MS). T......A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC...... such as [M−H+solvent]− and [(M−H)(M−H+Na)n]− were used to confirm the identity of the precursor ions. In relation to quantification of PFASs, we discuss how their surfactancy influence the ESI processes, challenge their handling in solution and choices of precursor-to-product ions for MSMS of e...

  16. Alkylation of mixed olefins with isobutane in a stratco chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vichailak, M. [ABB Lummus Global Inc., Houston, TX (United States); Hopper, J.R.; Yaws, C.L. [Lamar Univ., Beaumont, TX (United States); Pike, R.W. [Louisiana State Univ., Baton Rouge, LA (United States)

    1996-12-31

    The 17 reaction model for the sulfuric acid alkylation of isobutane with propylene as proposed by Langley and Pike has been used to simulate the effluent refrigeration reactor. The simulation conditions selected to minimize the formation of light and heavy by-product were determined to be: Temperature: 9 - 10 {degrees}C,- Isobutane/Olefin Ratio: 8 - 10; % Volume of Acid: 50 %. The reactor effluent composition from the simulation program has been used to compare with several sets of published data with reasonable agreement. This model has been extrapolated to simulate the alkylation of isobutane with butylenes and amylenes. The model will be optimized with commercial data. 9 refs., 6 figs., 1 tab.

  17. Reactions of Cyclopropanone Acetals with Alkyl Azides: Carbonyl Addition versus Ring-Opening Pathways

    Science.gov (United States)

    Grecian, Scott; Desai, Pankaj; Mossman, Craig; Poutsma, Jennifer L.; Aubé, Jeffrey

    2008-01-01

    The Lewis acid-mediated reactions of substituted cyclopropanone acetals with alkyl azides were found to strongly depend on the structure of the ketone component. When cyclopropanone acetal was treated with alkyl azides, N-substituted 2-azetidinones and ethyl carbamate products were obtained, arising from azide addition to the carbonyl, followed by ring expansion or rearrangement, respectively. When 2,2-dimethylcyclopropanone acetals were reacted with azides in the presence of BF3•OEt2, the products obtained were α-amino-α′-diazomethyl ketones, which arose from C2–C3 bond cleavage of the corresponding cyclopropanone, giving oxyallyl cations, that were captured by azides. Aryl-substituted cyclopropanone acetals, when subjected to these conditions, afforded [1,2,3]oxaborazoles exclusively, which were also the result of C2–C3 bond rupture, azide capture and then loss of nitrogen. In the reactions of n-hexyl-substituted cyclopropanone acetals with alkyl azides, a mixture of 2-azetidinones and regioisomeric [1,2,3]oxaborazoles were obtained. The reasons for the different behavior of the various systems is discussed. PMID:17985920

  18. Clean and Selective Catalytic C-H alkylation of Alkenes with Environmental friendly Alcohols

    KAUST Repository

    Poater, Albert

    2016-09-14

    Bearing the alkylation of alkene substrates using alcohol as solvent, catalysed by the cationic Ru-based catalyst [(C6H6)(PCy3)(CO)RuH]+, DFT calculations have been carried out to get mechanistic insights of such an environmental friendly reaction. Hard experimental conditions of Yi and coworkers [Science2011, 333, 1613] allow the formation of a C-C bond between indene and ethanol. The predicted mechanism suggests a cationic Ru-alkenyl species once two equivalents of indene interact releasing a molecule of indane subproduct. Then, oxidative addition of the Csingle bondO bond of alcohol to Ru-alkenyl species leads to Ru-alkenyl-alkyl species, followed by the reductive elimination process produces the desired alkylation product and a Ru-hydroxo complex. Finally, vinylic Csingle bondH activation and water elimination regenerates the Ru-alkenyl species. In this paper we present a full description of the complete reaction pathway along with possible alternative pathways, which are predicted to display higher upper barriers. Furthermore, the present study explains the possible reasons for the absence of undesired products such as indene dimer or hydroxylated indene in the experiments.

  19. P-Tether-Mediated, Iterative SN2'-Cuprate Alkylation Strategy to Skipped Polyol Stereotetrads: Utility of an Oxidative "Function Switch" with Phosphite-Borane Tethers.

    Science.gov (United States)

    Markley, Jana L; Hanson, Paul R

    2017-05-19

    The development of a P-tether-mediated, iterative S N 2'-cuprate alkylation protocol for the formation of 1,3-skipped polyol stereotetrads is reported. This two-directional synthetic strategy builds molecular complexity from simple, readily prepared C 2 -symmetric dienediols and unites the chemistry of both temporary phosphite-borane tethers and temporary phosphate tethers-through an oxidative "function switch" of the P-tether itself-to generate intermediates that were previously inaccessible via either method alone.

  20. Optimization of the alkyl side chain length of fluorine-18-labeled 7α-alkyl-fluoroestradiol

    International Nuclear Information System (INIS)

    Okamoto, Mayumi; Shibayama, Hiromitsu; Naka, Kyosuke; Kitagawa, Yuya; Ishiwata, Kiichi; Shimizu, Isao; Toyohara, Jun

    2016-01-01

    Introduction: Several lines of evidence suggest that 7α-substituted estradiol derivatives bind to the estrogen receptor (ER). In line with this hypothesis, we designed and synthesized 18 F-labeled 7α-fluoroalkylestradiol (Cn-7α-[ 18 F]FES) derivatives as molecular probes for visualizing ERs. Previously, we successfully synthesized 7α-(3-[ 18 F]fluoropropyl)estradiol (C3-7α-[ 18 F]FES) and showed promising results for quantification of ER density in vivo, although extensive metabolism was observed in rodents. Therefore, optimization of the alkyl side chain length is needed to obtain suitable radioligands based on Cn-7α-substituted estradiol pharmacophores. Methods: We synthesized fluoromethyl (23; C1-7α-[ 18 F]FES) to fluorohexyl (26; C6-7α-[ 18 F]FES) derivatives, except fluoropropyl (C3-7α-[ 18 F]FES) and fluoropentyl derivatives (C5-7α-[ 18 F]FES), which have been previously synthesized. In vitro binding to the α-subtype (ERα) isoform of ERs and in vivo biodistribution studies in mature female mice were carried out. Results: The in vitro IC 50 value of Cn-7α-FES tended to gradually decrease depending on the alkyl side chain length. C1-7α-[ 18 F]FES (23) showed the highest uptake in ER-rich tissues such as the uterus. Uterus uptake also gradually decreased depending on the alkyl side chain length. As a result, in vivo uterus uptake reflected the in vitro ERα affinity of each compound. Bone uptake, which indicates de-fluorination, was marked in 7α-(2-[ 18 F]fluoroethyl)estradiol (C2-7α-[ 18 F]FES) (24) and 7α-(4-[ 18 F]fluorobutyl)estradiol (C4-7α-[ 18 F]FES) (25) derivatives. However, C1-7α-[ 18 F]FES (23) and C6-7α-[ 18 F]FES (26) showed limited uptake in bone. As a result, in vivo bone uptake (de-fluorination) showed a bell-shaped pattern, depending on the alkyl side chain length. C1-7α-[ 18 F]FES (23) showed the same levels of uptake in uterus and bone compared with those of 16α-[ 18 F]fluoro-17β-estradiol. Conclusions: The optimal alkyl

  1. Inhibition of RecBCD enzyme by antineoplastic DNA alkylating agents.

    Science.gov (United States)

    Dziegielewska, Barbara; Beerman, Terry A; Bianco, Piero R

    2006-09-01

    To understand how bulky adducts might perturb DNA helicase function, three distinct DNA-binding agents were used to determine the effects of DNA alkylation on a DNA helicase. Adozelesin, ecteinascidin 743 (Et743) and hedamycin each possess unique structures and sequence selectivity. They bind to double-stranded DNA and alkylate one strand of the duplex in cis, adding adducts that alter the structure of DNA significantly. The results show that Et743 was the most potent inhibitor of DNA unwinding, followed by adozelesin and hedamycin. Et743 significantly inhibited unwinding, enhanced degradation of DNA, and completely eliminated the ability of the translocating RecBCD enzyme to recognize and respond to the recombination hotspot chi. Unwinding of adozelesin-modified DNA was accompanied by the appearance of unwinding intermediates, consistent with enzyme entrapment or stalling. Further, adozelesin also induced "apparent" chi fragment formation. The combination of enzyme sequestering and pseudo-chi modification of RecBCD, results in biphasic time-courses of DNA unwinding. Hedamycin also reduced RecBCD activity, albeit at increased concentrations of drug relative to either adozelesin or Et743. Remarkably, the hedamycin modification resulted in constitutive activation of the bottom-strand nuclease activity of the enzyme, while leaving the ability of the translocating enzyme to recognize and respond to chi largely intact. Finally, the results show that DNA alkylation does not significantly perturb the allosteric interaction that activates the enzyme for ATP hydrolysis, as the efficiency of ATP utilization for DNA unwinding is affected only marginally. These results taken together present a unique response of RecBCD enzyme to bulky DNA adducts. We correlate these effects with the recently determined crystal structure of the RecBCD holoenzyme bound to DNA.

  2. A yeast mutant specifically sensitive to bifunctional alkylation

    International Nuclear Information System (INIS)

    Ruhland, A.; Kircher, M.; Wilborn, F.; Brendel, M.

    1981-01-01

    A mutation that specifically confers sensitivity to bi- and tri-functional alkylating agents is presented. No or little cross-sensitivity to radiation or monofunctional agents could be detected. Sensitivity does not seem to be due to preferential alkylation of mutant DNA as parent and mutant strain exhibit the same amount of DNA alkylation and the same pattern of DNA lesions including interstrand crosslinks. The mutation is due to a defect in a nuclear gene which has been designated SNM1 (sensitive to nitrogen mustard); it may control an important step in the repair of DNA interstrand crosslinks (orig.(AJ)

  3. An adaptive response to alkylating agents in Aspergillus nidulans.

    Science.gov (United States)

    Hooley, P; Shawcross, S G; Strike, P

    1988-11-01

    A simple method is described for demonstrating adaptation to alkylation damage in Aspergillus nidulans. One wild type, two MNNG-sensitive, and one MNNG-resistant strain all showed improvement in colony growth when challenged with MNNG following appropriate inducing pretreatments. Other alkylating agents (MMS, EMS) could also adapt mycelium to later MNNG challenge, while 4NQO and UV could not. The inducible effect was not transmissible through conidia. A standard reversion assay based upon methG proved impractical for studying mutation frequencies during alkylation treatments owing to variations in MNNG resistance amongst revertants.

  4. Monitoring and Control of a Continuous Grignard Reaction for the Synthesis of an Active Pharmaceutical Ingredient Intermediate Using Inline NIR spectroscopy

    DEFF Research Database (Denmark)

    Cervera Padrell, Albert Emili; Nielsen, Jesper; Jønch Pedersen, Michael

    2012-01-01

    Inline near-infrared (NIR) spectroscopy has been used to monitor a continuous synthesis of an active pharmaceutical ingredient (API) intermediate by a Grignard alkylation reaction. The reaction between a ketone substrate and allylmagnesium chloride may form significant impurities with excess...

  5. Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

    Directory of Open Access Journals (Sweden)

    Charlotte Collet

    2016-02-01

    Full Text Available Efficient routes were developed for the diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. The key steps of the synthesis were the easy accessibility of different types of arms in term of configuration (myo and scyllo, the linking method and length, which could modulate the biological properties. These inositol derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments.

  6. Information acquisition and financial intermediation

    OpenAIRE

    Boyarchenko, Nina

    2012-01-01

    This paper considers the problem of information acquisition in an intermediated market, where the specialists have access to superior technology for acquiring information. These informational advantages of specialists relative to households lead to disagreement between the two groups, changing the shape of the intermediation-constrained region of the economy and increasing the frequency of periods when the intermediation constraint binds. Acquiring the additional information is, however, cost...

  7. Alkylsilyl Peroxides as Alkylating Agents in the Copper-Catalyzed Selective Mono-N-Alkylation of Primary Amides and Arylamines.

    Science.gov (United States)

    Sakamoto, Ryu; Sakurai, Shunya; Maruoka, Keiji

    2017-07-06

    The copper-catalyzed selective mono-N-alkylation of primary amides or arylamines using alkylsilyl peroxides as alkylating agents is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the alkylsilyl peroxides, as well as to the primary amides and arylamines. Mechanistic studies suggest that the present reaction should proceed through a free-radical process that includes alkyl radicals generated from the alkylsilyl peroxides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Regulation of DNA Alkylation Damage Repair: Lessons and Therapeutic Opportunities.

    Science.gov (United States)

    Soll, Jennifer M; Sobol, Robert W; Mosammaparast, Nima

    2017-03-01

    Alkylation chemotherapy is one of the most widely used systemic therapies for cancer. While somewhat effective, clinical responses and toxicities of these agents are highly variable. A major contributing factor for this variability is the numerous distinct lesions that are created upon alkylation damage. These adducts activate multiple repair pathways. There is mounting evidence that the individual pathways function cooperatively, suggesting that coordinated regulation of alkylation repair is critical to prevent toxicity. Furthermore, some alkylating agents produce adducts that overlap with newly discovered methylation marks, making it difficult to distinguish between bona fide damaged bases and so-called 'epigenetic' adducts. Here, we discuss new efforts aimed at deciphering the mechanisms that regulate these repair pathways, emphasizing their implications for cancer chemotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Detection of Alkylating Agents using Electrical and Mechanical Means

    International Nuclear Information System (INIS)

    Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Eichen, Yoav; Tal, Shay; Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir

    2011-01-01

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  10. Direct N-alkylation of unprotected amino acids with alcohols

    NARCIS (Netherlands)

    Yan, Tao; Feringa, Ben L; Barta, Katalin

    2017-01-01

    N-alkyl amino acids find widespread application as highly valuable, renewable building blocks. However, traditional synthesis methodologies to obtain these suffer from serious limitations, providing a major challenge to develop sustainable alternatives. We report the first powerful catalytic

  11. Regeneration of a deactivated USY alkylation catalyst using supercritical isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; David N. Ghompson; Kyle C. Burch

    2005-01-01

    Off-line, in-situ alkylation activity recovery from a completely deactivated solid acid catalyst was examined in a continuous-flow reaction system employing supercritical isobutane. A USY zeolite catalyst was initially deactivated during the liquid phase alkylation of butene with isobutane in a single-pass reactor and then varying amounts of alkylation activity were recovered by passing supercritical isobutane over the catalyst bed at different reactivation conditions. Temperature, pressure and regeneration time were found to play important roles in the supercritical isobutane regeneration process when applied to a completely deactivated USY zeolite alkylation catalyst. Manipulation of the variables that influence solvent strength, diffusivity, surface desorption, hydride transfer rates, and coke aging, strongly influence regeneration effectiveness.

  12. Fluorinated Alkyl Ether Epoxy Resin Compositions and Applications Thereof

    Science.gov (United States)

    Wohl, Christopher J. (Inventor); Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Siochi, Emilie J. (Inventor); Gardner, John M. (Inventor); Palmieri, Frank M. (Inventor)

    2017-01-01

    Epoxy resin compositions prepared using amino terminated fluoro alkyl ethers. The epoxy resin compositions exhibit low surface adhesion properties making them useful as coatings, paints, moldings, adhesives, and fiber reinforced composites.

  13. Dynamic studies of poly(di-n-alkyl itaconate)s

    CERN Document Server

    Arrighi, V; Gagliardi, S; McEwen, I J; Telling, M T F

    2002-01-01

    We report a preliminary dynamic study of poly(di-n-alkyl itaconate)s with varying side chain length n. QENS measurements were carried out on two backscattering spectrometers, IRIS at ISIS and IN10 at the ILL in the temperature range of 4 to 350 K. We show that molecular motion can be detected well below the polymer glass transition for all samples. It is possible to distinguish different dynamic processes. The temperature range over which these are observed is dependent on the length of the side chain, n. The intermediate scattering function, I(Q,t), was determined from the IRIS and found to obey time-temperature superposition. We show that the I(Q,t) data at different temperatures can be overlapped using the same time-scale shift factors, indicating that the relaxation process is common to all the polymers investigated. (orig.)

  14. Iminium Salts by Meerwein Alkylation of Ehrlich’s Aldehyde

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2013-03-01

    Full Text Available 4-(Dimethylaminobenzaldehyde is alkylated at the N atom by dialkyl sulfates, MeI, or Me3O BF4. In contrast, ethylation by Et3O BF4 occurs selectively at the O atom yielding a quinoid iminium ion. 4-(Diethylaminobenzaldehyde is alkylated only at O by either Et or Me oxonium reagent. The iminium salts are prone to hydrolysis giving the corresponding hydrotetrafluoroborates. Five crystal structures were determined.

  15. New insight into the spatiotemporal variability and source apportionments of C1–C4 alkyl nitrates in Hong Kong

    Directory of Open Access Journals (Sweden)

    Z. Ling

    2016-07-01

    Full Text Available C1–C4 alkyl nitrates (RONO2 were measured concurrently at a mountain site, Tai Mo Shan (TMS, and an urban site, Tsuen Wan (TW, at the base of the same mountain in Hong Kong from September to November 2010. Although the levels of parent hydrocarbons were much lower at TMS (p  <  0.05, similar alkyl nitrate levels were found at both sites regardless of the elevation difference, suggesting various source contributions of alkyl nitrates at the two sites. Prior to using a positive matrix factorization (PMF model, the data at TW were divided into "meso" and "non-meso" scenarios for the investigation of source apportionments with the influence of mesoscale circulation and regional transport, respectively. Secondary formation was the prominent contributor of alkyl nitrates in the meso scenario (60 ± 2 %, 60.2 ± 1.2 pptv, followed by biomass burning and oceanic emissions, while biomass burning and secondary formation made comparable contributions to alkyl nitrates in the non-meso scenario, highlighting the strong emissions of biomass burning in the inland Pearl River delta (PRD region. In contrast to TW, the alkyl nitrate levels measured at TMS mainly resulted from the photooxidation of the parent hydrocarbons at TW during mesoscale circulation, i.e., valley breezes, corresponding to 52–86 % of the alkyl nitrate levels at TMS. Furthermore, regional transport from the inland PRD region made significant contributions to the levels of alkyl nitrates (∼  58–82 % at TMS in the non-meso scenario, resulting in similar levels of alkyl nitrates observed at the two sites. The simulation of secondary formation pathways using a photochemical box model found that the reaction of alkyl peroxy radicals (RO2 with nitric oxide (NO dominated the formation of RONO2 at both sites, and the formation of alkyl nitrates contributed negatively to O3 production, with average reduction rates of 4.1 and 4.7 pptv pptv−1 at TMS and TW

  16. Enantioselective γ-Alkylation of α,β-Unsaturated Malonates and Ketoesters by a Sequential Ir-Catalyzed Asymmetric Allylic Alkylation/Cope Rearrangement

    OpenAIRE

    Liu, Wen-Bo; Okamoto, Noriko; Alexy, Eric J.; Hong, Allen Y.; Tran, Kristy; Stoltz, Brian M.

    2016-01-01

    A catalytic, enantioselective ? -alkylation of ?,?-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- and enantioselective iridium-catalyzed ?-alkylation of an extended enolate, and a subsequent translocation of chirality to the ?-position via a Cope rearrangement.

  17. Pulse radiolysis of alkanes: a time-resolved EPR study - Part I. Alkyl radicals

    International Nuclear Information System (INIS)

    Shkrob, I.A.; Trifunac, A.D.

    1995-01-01

    Time-resolved EPR was applied to detect short-lived alkyl radicals in pulse radiolysis of liquid alkanes. Two problems were addressed: (i) the mechanism of radical formation and (ii) the mechanism of chemically-induced spin polarization in these radicals. (i) The ratio of yields of penultimate and interior radicals in n-alkanes at the instant of their generation was found to be ≅ 1.25 times greater than the statistical quantity. This higher-than-statistical production of penultimate radicals indicates that the proton transfer reaction involving excited radical cations must be a prevailing route of radical generation. The relative yields of hydrogen abstraction and fragmentation for various branched alkanes are estimated. It is concluded that the fragmentation occurs prior to the formation of radicals in an excited precursor species. (ii) The analysis of spin-echo kinetics in n-alkanes suggests that the alkyl radicals gain the emissive polarization in spur reactions. This initial polarization increases with shortening of the aliphatic chain. We suggest that the origin of this polarization is the ST mechanism operating in the pairs of alkyl radicals and hydrogen atoms generated in dissociation of excited alkane molecules. It is also found that a long-chain structure of alkyl radicals results in much higher rate of Heisenberg spin exchange relative to the recombination rate (up to 30 times). That suggests prominent steric effects in recombination or the occurrence of through-chain electron exchange. The significance of these results in the context of cross-linking in polyethylene and higher paraffins is discussed. (Author)

  18. Salvage of Failed Protein Targets by Reductive Alkylation

    Science.gov (United States)

    Tan, Kemin; Kim, Youngchang; Hatzos-Skintges, Catherine; Chang, Changsoo; Cuff, Marianne; Chhor, Gekleng; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw; An, Hao; Babnigg, Gyorgy; Bigelow, Lance; Joachimiak, Grazyna; Li, Hui; Mack, Jamey; Makowska-Grzyska, Magdalena; Maltseva, Natalia; Mulligan, Rory; Tesar, Christine; Zhou, Min; Joachimiak, Andrzej

    2014-01-01

    The growth of diffraction-quality single crystals is of primary importance in protein X-ray crystallography. Chemical modification of proteins can alter their surface properties and crystallization behavior. The Midwest Center for Structural Genomics (MCSG) has previously reported how reductive methylation of lysine residues in proteins can improve crystallization of unique proteins that initially failed to produce diffraction-quality crystals. Recently, this approach has been expanded to include ethylation and isopropylation in the MCSG protein crystallization pipeline. Applying standard methods, 180 unique proteins were alkylated and screened using standard crystallization procedures. Crystal structures of 12 new proteins were determined, including the first ethylated and the first isopropylated protein structures. In a few cases, the structures of native and methylated or ethylated states were obtained and the impact of reductive alkylation of lysine residues was assessed. Reductive methylation tends to be more efficient and produces the most alkylated protein structures. Structures of methylated proteins typically have higher resolution limits. A number of well-ordered alkylated lysine residues have been identified, which make both intermolecular and intramolecular contacts. The previous report is updated and complemented with the following new data; a description of a detailed alkylation protocol with results, structural features, and roles of alkylated lysine residues in protein crystals. These contribute to improved crystallization properties of some proteins. PMID:24590719

  19. Regioselective 1-N-Alkylation and Rearrangement of Adenosine Derivatives.

    Science.gov (United States)

    Oslovsky, Vladimir E; Drenichev, Mikhail S; Mikhailov, Sergey N

    2015-01-01

    Several methods for the preparation of some N(6)-substituted adenosines based on selective 1-N-alkylation with subsequent Dimroth rearrangement were developed. The proposed methods seem to be effective for the preparation of natural N(6)-isopentenyl- and N(6)-benzyladenosines, which are known to possess pronounced biological activities. Direct 1-N-alkylation of 2',3',5'-tri-O-acetyladenosine and 3',5'-di-O-acetyl-2'-deoxyadenosine with alkyl halides in N,N-dimethylformamide (DMF) in the presence of BaCO3 and KI gave 1-N-substituted derivatives with quantitative yields, whereas 1-N-alkylation of adenosine was accompanied by significant O-alkylation. Moreover, the reaction of trimethylsilyl derivatives of N(6)-acetyl-2',3',5'-tri-O-acetyladenosine and N(6)-acetyl-3',5'-di-O-acetyl-2'-deoxyadenosine with alkyl halides leads to the formation of the stable 1-N-substituted adenosines. Dimroth rearrangement of 1-N-substituted adenosines in aqueous ammonia yields pure N(6)-substituted adenosines.

  20. On the role of alkylating mechanisms, O-alkylation and DNA-repair in genotoxicity and mutagenicity of alkylating methanesulfonates of widely varying structures in bacterial systems.

    Science.gov (United States)

    Eder, E; Kütt, W; Deininger, C

    2001-07-31

    The Ames test and the SOS-chromotest are widely used bacterial mutagenicity/genotoxicity assays to test potential carcinogens. Though the molecular mechanisms leading to backmutations and to the induction of SOS-repair are in principle known the role of alkylation mechanisms, of different DNA-lesions and of DNA-repair is in parts still unknown. In this study we investigated 14 monofunctional methanesulfonates of widely varying structures for mutagenicity in Salmonella typhimurium strain TA 1535 sensitive for O(6)-guanine alkylation for comparison with strain TA 100 in order to obtain additional information on the role of alkylation mechanisms, formation of the procarcinogenic DNA-lesion O(6)-alkylguanine and the role of DNA-repair in induction of backmutation. The substances were also tested in the SOS-chromotest with Escherichia coli strain PQ 37 and strain PQ 243 lacking alkyl base glycosylases important for base excision repair in order to examine the role of alkylation mechanisms, of base excision repair and the role of O-alkyl and N-alkyl DNA-lesions on the induction of SOS-repair. The secondary methanesulfonates with very high S(N)1-reactivity isopropyl methanesulfonate and 2-butyl methanesulfonate showed highest mutagenicities in both strains. The higher substituted methanesulfonates with very high S(N)1-reactivity had lower mutagenic activities because of reduced half lives due to their high hydrolysis rates. A clear increase in mutagenicities in strain TA 100 was observed for the primary compounds methyl methanesulfonate and allyl methanesulfonate with very high S(N)2-reactivity. The primary compound phenylethyl methanesulfonate has a relatively high mutagenicity in both Salmonella strains which can be explained by an increased S(N)1-reactivity and by low repair of the O(6)-phenylethylguanine. Highest SOSIPs (SOS inducing potency) in strains PQ 37 and PQ 243 were found for methyl methanesulfonate and for the secondary compounds with high S(N)1-reactivity

  1. Alkyl-halogenide promoted ionic liquid catalysis of isobutane/butene-alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Schilder, L.; Korth, W.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2011-07-01

    The effect of two different types of promoters on the performance of Lewis-acidic chloroaluminate ionic liquid catalysts was studied for liquid liquid biphasic isobutane/2-butene alkylation. In particular, the activity and selectivity of such catalytic systems was investigated. Experimental results obtained from a batch reactor show, that tert-butyl halides increase the reaction rate significantly and shift the C8-selectivity towards the desired high-octane trimethylpentanes (TMPs). But, secondary reactions like oligomerization and cracking are not affected by the use of these promoters. (orig.)

  2. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  3. Electrical conductivity optimization of the Na3AlF6-Al2O3-Sm2O3 molten salts system for Al-Sm intermediate binary alloy production

    Science.gov (United States)

    Liao, Chun-fa; Jiao, Yun-fen; Wang, Xu; Cai, Bo-qing; Sun, Qiang-chao; Tang, Hao

    2017-09-01

    Metal Sm has been widely used in making Al-Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al-Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant (CVCC) technique was used to measure the conductivity for the Na3AlF6-AlF3-LiF-MgF2-Al2O3-Sm2O3 electrolysis medium in the temperature range from 905 to 1055°C. The temperature ( t) and the addition of Al2O3 ( W(Al2O3)), Sm2O3 ( W(Sm2O3)), and a combination of Al2O3 and Sm2O3 into the basic fluoride system were examined with respect to their effects on the conductivity ( κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature ( t) and decreases with the addition of Al2O3 or Sm2O3 or both. We concluded that the optimal operation conditions for Al-Sm intermediate alloy production in the Na3AlF6-AlF3-LiF-MgF2-Al2O3-Sm2O3 system are W(Al2O3) + W(Sm2O3) = 3wt%, W(Al2O3): W(Sm2O3) = 7:3, and a temperature of 965 to 995°C, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.

  4. DNA minor groove targeted alkylating agents based on bisbenzimidazole carriers: synthesis, cytotoxicity and sequence-specificity of DNA alkylation.

    Science.gov (United States)

    Smaill, J B; Fan, J Y; Denny, W A

    1998-12-01

    A series of bisbenzimidazoles bearing a variety of alkylating agents [ortho- and meta-mustards, imidazolebis(hydroxymethyl), imidazolebis(methylcarbamate) and pyrrolebis(hydroxymethyl)], appended by a propyl linker chain, were prepared and investigated for sequence-specificity of DNA alkylation and their cytotoxicity. Previous work has shown that, for para-aniline mustards, a propyl linker is optimal for cytotoxicity. Alkaline cleavage assays using a variety of different labelled oligonucleotides showed that the preferred sequences for adenine alkylation were 5'-TTTANANAANN and 5'-ATTANANAANN (underlined bases show the drug alkylation sites), with AT-rich sequences required on both the 5' and 3' sides of the alkylated adenine. The different aniline mustards showed little variation in alkylation pattern and similar efficiencies of DNA cross-link formation despite the changes in orientation and positioning of the mustard, suggesting that the propyl linker has some flexibility. The imidazole- and pyrrolebis(hydroxymethyl) alkylators showed no DNA strand cleavage following base treatment, indicating that no guanine or adenine N3 or N7 adducts were formed. Using the PCR-based polymerase stop assay, these alkylators showed PCR blocks at 5'-C*G sites (the * nucleotide indicates the blocked site), particularly at 5'-TAC*GA 5'-AGC*GGA, and 5'-AGCC*GGT sequences, caused by guanine 2-NH2 lesions on the opposite strand. Only the (more reactive) imidazolebis(methylcarbamoyl) and pyrrolebis(hydroxymethyl) alkylators demonstrated interstrand cross-linking ability. All of the bifunctional mustards showed large (approximately 100-fold) increases in cytotoxicity over chlorambucil, with the corresponding monofunctional mustards being 20- to 60-fold less cytotoxic. These results suggest that in the mustards the propyl linker provides sufficient flexibility to achieve delivery of the alkylator to favoured (adenine N3) sites in the minor groove, regardless of its exact geometry with

  5. Decorating poly(alkyl aryl-ether) dendrimers with metallacarboranes.

    Science.gov (United States)

    Núñez, Rosario; Juárez-Pérez, Emilio José; Teixidor, Francesc; Santillan, Rosa; Farfán, Norberto; Abreu, Arturo; Yépez, Rebeca; Viñas, Clara

    2010-11-01

    A new family of polyanionic poly(alkyl aryl-ether) metallodendrimers decorated with four and eight cobaltabisdicarbollide units have been obtained in high yield by the ring-opening reaction of cyclic oxonium [3,3'-Co(8-(C(2)H(4)O)(2)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))] with alkoxides formed by deprotonation of terminal alcohols in the α,α'-bis[3,5-bis(hydroxymehyl)phenoxy]-p-xylene, α,α'-bis[3,5-bis(hydroxymehyl)phenoxy]-m-xylene, α,α'-bis[3,5-bis-[3,5-bis(hydroxymethyl)phenoxy]methylen]phenoxy]-p-xylene, and α,α,'-bis[3,5-bis-[3,5-bis(hydroxymethyl)phenoxy]methylen]phenoxy]-m-xylene dendrimers. The crystal structure of the precursor α,α'-bis[3,5-bis(chloromethyl)phenoxy]-p-xylene is also described. Final products are fully characterized by FTIR, NMR, UV-vis spectroscopies and elemental analysis. For metallodendrimers, the UV-vis absorptions have been a good tool for estimating the experimental number of cobaltabisdicarbollide units peripherally attached to the dendrimeric structure and consequently to corroborate the complete functionalization of the dendrimers.

  6. UV absorption spectra and kinetics for alkyl and alkyl peroxy radicals originating from di-tert-butyl ether

    DEFF Research Database (Denmark)

    Nielsen, O.J.; Sehested, J.; Langer, S.

    1995-01-01

    Alkyl, (CH3)(3)COC(CH3)(2)CH2, and alkyl peroxy, (CH3)(3)COC(CH3)(2)CH2O2, radicals from di-tert-butyl ether (DTBE), have been studied in the gas phase at 296 K. A pulse radiolysis UV absorption technique was used to measure the spectra and kinetics. Absorption cross sections were quantified over...

  7. Propargyl organometallic compounds. II. Alkylation of sodium derivatives of 1-alkyl-1-aryl-2-alkynes in liquid ammonia

    International Nuclear Information System (INIS)

    Libman, N.M.; Sevryukov, Yu.P.

    1987-01-01

    In most cases the alkylation of the sodium derivatives of 1-phenyl-1-alkyl-2-alkynes by methyl, ethyl, isopropyl, and tert-butyl bromides in liquid ammonia takes place preferentially at the sp 2 -hybridized carbon atom, and this leads to the formation of the corresponding acetylenes, The regioselectivity of the reaction is explained by the greater softness of the trigonal atom of the ambient propargyl anion and its smaller screening by the solvate shell compared with the diagonal atom

  8. Silvicultural aspects intermediate cuttings

    Science.gov (United States)

    Kenneth L. Carvell

    1971-01-01

    Correct timing of the first thinning in mixed oak stands depends largely on the composition and condition of the stands and on available markets for small wood products. Delaying first thinnings in high-quality seedling-origin stands until a long, straight, clear bole has developed is of primary importance in assuring high quality of the final crop trees. However, many...

  9. Intermediate Vector Boson

    Indian Academy of Sciences (India)

    Keith Ulmer

    in a quantum field theory, there exists a massless scalar (spin-0) boson ... Do not know its mass. ❖. Production rate is very very low in comparison with other physics process, need. ➢. High luminosity,. ➢. High energy. ➢. High precision ..... Magnificent triumph of human thought and intelligence! But still strong interaction is ...

  10. Intermediate mass dimuon events

    International Nuclear Information System (INIS)

    Moser, H.-G.

    1985-01-01

    We report the observation of 67 dimuon events at the CERN p anti p collider with the UA1 detector. The events will be interpreted in terms of the Drell-Yan mechanism, J/PSI and UPSILON decays and heavy flavour production. (author)

  11. Depolymerization of coal by oxidation and alkylation; Sanka bunkai to alkyl ka ni yoru sekitan kaijugo

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, H.; Isoda, T.; Kusakabe, K.; Morooka, S. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hayashi, J. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

    1996-10-28

    Change in depolymerization degree and coal structure was studied for depolymerization treatment of coal in various alcohol containing aqueous hydrogen peroxide. In experiment, the mixture of Yallourn coal, alcohol and aqueous hydrogen peroxide was agitated in nitrogen atmosphere of normal pressure at 70{degree}C for 12 hours. As the experimental result, the methanol solubility of only 5% of raw coal increased up to 35.2% by hydrogen peroxide treatment, while the yield of insoluble matters also decreased from 94% to 62%. Most of the gas produced during treatment was composed of inorganic gases such as CO and CO2, and its carbon loss was extremely decreased by adding alcohol. From the analytical result of carbon loss in hydrogen peroxide treatment, it was clarified that alkylation advances with introduction of alkyl group derived from alcohol into coal by hydrogen peroxide treatment under a coexistence of alcohol, and depolymerization reaction of coal itself is thus promoted by alcohol. 4 refs., 7 figs., 1 tab.

  12. Early Transition Metal Alkyl and Tetrahydroborate Complexes.

    Science.gov (United States)

    Jensen, James Allen

    1988-06-01

    An investigation of early transition metal alkyl and tetrahydroborate complexes as catalytic models and ceramic precursors has been initiated. The compounds MX _2 (dmpe)_2, dmpe = 1,2-bis(dimethylphosphino)ethane, for M = Ti, V, Cr, and X = Br, I, BH_4, have been prepared. These complexes are paramagnetic and have been shown by X-ray crystallography to have trans-octahedral structures. The BH_4^{-} groups in Ti(BH_4)_2(dmpe) _2 bond to the metal in a bidentate manner. This structure is in marked contrast to the structure of the vanadium analogue, V(BH_4)_2 (dmpe)_2, which displays two unidentate BH_4^{-} groups. Alkylation of Ti(BH_4)_2 (dmpe)_2 with LiMe results in the complex TiMe_2(dmpe) _2 which is diamagnetic in both solution and solid state. Single crystal X-ray and neutron diffraction studies show that there may be strong Ti-C pi -bonding. A tetragonal compression along the C -Ti-C bond vector accounts for the observed diamegnetism. A series of complexes of the formula Ti(BH _4)_3(PR_3)_2 has been prepared where PR_3 = PMe_3, PEt_3, PMe_3Ph, and P(OMe)_3 . The X-ray crystal structure of Ti(BH _4)_3(PMe_3)_2 reveals a pseudo trigonal bipyramidal geometry in which two BH_4^{-} groups display an unusual "side-on" bonding mode. The "side-on" ligation mode has been attributed to a Jahn-Teller distortion of the orbitally degenerate d^1 ground state. In contrast, the non-Jahn-Teller susceptible vanadium analogue, V(BH_4)_3 (PMe_3)_2, possesses a nearly ideal D_{rm 3h} >=ometry with three bidentate tetrahydroborate groups. Addition of excess PMe_3 to V(BH_4)_3(PMe _3)_2water forms the vanadium(III) oxo dimer (V(BH_4)_2 (PMe_3)_2]_2 [mu-O) which has been structurally characterized. The compound Ti(CH_2CMe _3)_4 can be prepared by addition of Ti(OEt)_4 to LiCH_2 CMe_3. Sublimation of Ti(CH _2CMe_3)_4 over a substrate heated to 250^ circC results in the chemical vapor deposition of amorphous TiC thin films. This CVD approach has been extended to the Group 4 borides: Ti

  13. SERIES: Genomic instability in cancer Balancing repair and tolerance of DNA damage caused by alkylating agents

    Science.gov (United States)

    Fu, Dragony; Calvo, Jennifer A.; Samson, Leona D

    2013-01-01

    Alkylating agents comprise a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER), and mismatch repair (MMR) respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for an organism's favorable response to alkylating agents. Furthermore, an individual's response to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity. PMID:22237395

  14. A protic ionic liquid as an atom economical solution for palladium catalyzed asymmetric allylic alkylation.

    Science.gov (United States)

    Guerrero-Ríos, Itzel; Ortiz-Ramírez, Alfonso H; van Leeuwen, Piet W N M; Martin, Erika

    2018-03-12

    The asymmetric allylic alkylation of rac-1,3-diphenyl-3-acetoxyprop-1-ene (I) catalysed by palladium and diverse phosphorus containing ligands [(S)-BINAP, (R,R)-Chiraphite and (R,R)-Et-Duphos] in an ionic liquid [HDBU][OAc] was successfully performed, achieving full conversions and up to 96% ee of the (S)-product when (R,R)-Et-Duphos was used as a ligand. The reaction could be performed using an equimolar amount of substrate, malonate and base DBU, in which case the total products sum to the desired alkylated product and the ionic pair [HDBU][OAc]; this system thus produces its own IL solvent as the only co-product. These catalytic systems were active in recycling experiments for up to four cycles, albeit with a loss of activity due to the poor retention of palladium in the ionic liquid. The catalytic performance of each Pd/ligand system was optimized by varying the ratio of the substrate and malonate. Systems based on [HDBU][OAc] were found to be the best.

  15. Effect of Amphiphilic Alkyl Chain Length Upon Purified LATEX Stability

    International Nuclear Information System (INIS)

    Amira Amir Hassan; Amir Hashim Mohd Yatim

    2015-01-01

    Rubber particles in purified latex (PL) are stabilized by a film of protein and fatty acid soap (surfactant). Saturated straight-chain fatty acid soaps can assist an enhancement of latex stability. However, whether the alkyl chain length plays an important role in increasing the stability is still an issue. The aim of this study is to investigate the effect of alkyl chain length of anionic surfactant on the stability of purified latex. The fatty acid soap of decanoate (9), laurate (11), sodium dodecyl sulphate (SDS) (12) and palmitate (15) were used. The numbers in parentheses indicating the number of carbon present in alkyl chain of the soap. The results showed that the impact of alkyl chain length on the stability of latex is in the order of laurate > decanoate > SDS > palmitate > purified latex accordingly. The alkyl chain length does giving a significant effect on latex stability after longer stirring time. The particle size of latex with the presence of surfactant is greater compare to a single particle itself due to extension of particles diameter. Thus suitable interaction of the nonpolar tail of surfactant with the hydrophobic regions of latex surface played a major role in maintaining a stable latex system. (author)

  16. Effect of curcumin on the genotoxicity induced by alkylating agents

    Directory of Open Access Journals (Sweden)

    İbrahim Hakkı Ciğerci

    2015-06-01

    Full Text Available The protection of the structure of DNA is extremly important to transfer genetic information from generation to generation. DNA damage due to genotoxic ess is an important type of stress which organisms are exposed during their life. The factors that cause DNA damage can be endogenous and exogenous. Among exogenous sources, alkylating agents comes first to cause DNA damage. Alkylating exogenous agents are capable of adding bases to ethyl or methyl groups. The direct-acting alkylating agent methyl methanesulfonate (MMS, is covalently linked to DNA and cause DNA damage, creating an indirect effect of the alkylating agent. cyclophosphamide (CP causes the DNA damage by changing the function of cellular proteins. Both substances have been shown to induce gene mutations in prokaryotes and eukaryotes, chromosome effects, unscheduled DNA synthesis and sister chromatid exchange. Furthermore, cessation of cell growth arrest and DNA damage causing changes in gene expression have been observed by the stress due to alkylating agents exposure. In this study, the effects of curcumin on MMS and CP treated mice were investigated. Alkaline comet assay was used to detect DNA damage. Curcumin reduced the DNA damage, occurred by both MMS and CP induction. We could state that curcumin, a phenolic compound shows protective effects before the damage. In brief, curcumin has both antioxidant and antigenotoxic effects.

  17. Identification of degradation products of ionic liquids in an ultrasound assisted zero-valent iron activated carbon micro-electrolysis system and their degradation mechanism.

    Science.gov (United States)

    Zhou, Haimei; Lv, Ping; Shen, Yuanyuan; Wang, Jianji; Fan, Jing

    2013-06-15

    Ionic liquids (ILs) have potential applications in many areas of chemical industry because of their unique properties. However, it has been shown that the ILs commonly used to date are toxic and not biodegradable in nature, thus development of efficient chemical methods for the degradation of ILs is imperative. In this work, degradation of imidazolium, piperidinium, pyrrolidinium and morpholinium based ILs in an ultrasound and zero-valent iron activated carbon (ZVI/AC) micro-electrolysis system was investigated, and some intermediates generated during the degradation were identified. It was found that more than 90% of 1-alkyl-3-methylimidazolium bromide ([Cnmim]Br, n = 2, 4, 6, 8, 10) could be degraded within 110 min, and three intermediates 1-alkyl-3-methyl-2,4,5-trioxoimidazolidine, 1-alkyl-3-methylurea and N-alkylformamide were detected. On the other hand, 1-butyl-1-methylpiperidinium bromide ([C4mpip]Br), 1-butyl-1-methylpyrrolidinium bromide ([C4mpyr]Br) and N-butyl-N-methylmorpholinium bromide ([C4mmor]Br) were also effectively degraded through the sequential oxidization into hydroxyl, carbonyl and carboxyl groups in different positions of the butyl side chain, and then the N-butyl side chain was broken to form the final products of N-methylpiperidinium, N-methylpyrrolidinium and N-methylmorpholinium, respectively. Based on these intermediate products, degradation pathways of these ILs were suggested. These findings may provide fundamental information on the assessment of the factors related to the environmental fate and environmental behavior of these commonly used ILs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Bis(Cyclic Alkyl Amino Carbene) Ruthenium Complexes: A Versatile, Highly Efficient Tool for Olefin Metathesis.

    Science.gov (United States)

    Gawin, Rafał; Kozakiewicz, Anna; Guńka, Piotr A; Dąbrowski, Paweł; Skowerski, Krzysztof

    2017-01-19

    The state-of-the-art in olefin metathesis is application of N-heterocyclic carbene (NHC)-containing ruthenium alkylidenes for the formation of internal C=C bonds and of cyclic alkyl amino carbene (CAAC)-containing ruthenium benzylidenes in the production of terminal olefins. A straightforward synthesis of bis(CAAC)Ru indenylidene complexes, which are highly effective in the formation of both terminal and internal C=C bonds at loadings as low as 1 ppm, is now reported. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Operating experience with unit for sulfuric acid alkylation of isobutane by butylenes

    Energy Technology Data Exchange (ETDEWEB)

    Tagavov, I.T.; Sumanov, V.T.; Khadzhiev, S.N.

    1988-09-01

    The operation of units for the sulfuric acid alkylation of isobutanes by butylenes have been performed. The reaction was carried out in a KSG-3 horizontal sulfuric acid contractor. A butane-butylene fraction from catalytic cracking and an isobutane fraction from the central gas fractionating unit were used as a feedstock. The studies have shown that the unit will give a high-quality product under various conditions of operation. The specific consumption of sulfuric acid in processing different types of feed remains within acceptable limits.

  20. Nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1991-01-01

    The theme that unites the sometimes seemingly disparate experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in their radiative decays in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of our BNL experiments E810, E854, as well as our approved experiment at RHIC), -- all these projects share this common goal. Our other experiments represent different approaches to the same broad undertaking. LAMPF E1097 will provide definitive answers to the question of the spin dependence of the inelastic channel of pion production in the n-p interaction. FNAL E683 may well open a new field of investigation in nuclear physics: that of just how quarks and gluons interact with nuclear matter as they transverse nuclei of different sizes. In most all of the experiments mentioned above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are unavailable to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do

  1. Nuclear structure at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Bonner, B.E.; Mutchler, G.S.

    1991-09-30

    The theme that unites the sometimes seemingly disparate experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in their radiative decays in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of our BNL experiments E810, E854, as well as our approved experiment at RHIC), -- all these projects share this common goal. Our other experiments represent different approaches to the same broad undertaking. LAMPF E1097 will provide definitive answers to the question of the spin dependence of the inelastic channel of pion production in the n-p interaction. FNAL E683 may well open a new field of investigation in nuclear physics: that of just how quarks and gluons interact with nuclear matter as they transverse nuclei of different sizes. In most all of the experiments mentioned above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are unavailable to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do.

  2. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  3. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    Energy Technology Data Exchange (ETDEWEB)

    Costarrosa, L. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Calvino-Casilda, V. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Ferrera-Escudero, S. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Duran-Valle, C.J. [Dpto. de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071 Badajoz (Spain); Martin-Aranda, R.M. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain)]. E-mail: rmartin@ccia.uned.es

    2006-06-30

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N{sub 2} adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

  4. Safety Assessment of Alkyl Ethylhexanoates as Used in Cosmetics.

    Science.gov (United States)

    Fiume, Monice; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-01-01

    The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) assessed the safety of 16 alkyl ethylhexanoates for use in cosmetics, concluding that these ingredients are safe in cosmetic formulations in the present practices of use and concentrations when formulated to be nonirritating. The alkyl ethylhexanoates primarily function as skin-conditioning agents in cosmetics. The highest concentration of use reported for any of the alkyl ethylhexanoates is 77.3% cetyl ethylhexanoate in rinse-off formulations used near the eye, and the highest leave-on use reported is 52% cetyl ethylhexanoate in lipstick formulations. The Panel reviewed available animal and clinical data related to these ingredients, and the similarities in structure, properties, functions, and uses of ingredients from previous CIR assessments on constituent alcohols that allowed for extrapolation of the available toxicological data to assess the safety of the entire group. © The Author(s) 2015.

  5. From old alkylating agents to new minor groove binders.

    Science.gov (United States)

    Puyo, Stéphane; Montaudon, Danièle; Pourquier, Philippe

    2014-01-01

    Alkylating agents represent the oldest class of anticancer agents with the approval of mechloretamine by the FDA in 1949. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in the treatment of specific malignancies, sometimes representing the unique option for the treatment of refractory tumors. Here, we are reviewing the major classes of alkylating agents, with a particular focus on the latest generations of compounds that specifically target the minor groove of the DNA. These naturally occurring derivatives have a unique mechanism of action that explains the recent regain of interest in developing new classes of alkylating agents that could be used in combination with other anticancer drugs to enhance tumor response in the clinic. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    International Nuclear Information System (INIS)

    Costarrosa, L.; Calvino-Casilda, V.; Ferrera-Escudero, S.; Duran-Valle, C.J.; Martin-Aranda, R.M.

    2006-01-01

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N 2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation

  7. Selective mono-alkylation of N-methoxybenzamides.

    Science.gov (United States)

    Chen, Zenghua; Hu, Le'an; Zeng, Fanyun; Zhu, Ranran; Zheng, Shasha; Yu, Qingzhen; Huang, Jianhui

    2017-04-11

    We report our latest discovery of norbornene derivative modulated highly mono-selective ortho-C-H activation alkylation reactions on arenes bearing simple mono-dentate coordinating groups. The reaction features the use of readily available benzamides and alkyl halides. During the study, we prepared 30 mono-alkylated aryl amides in good yields with good mono-selectivity. We have also demonstrated that structurally rigid alkenes such as norbornene and its derivatives are a good class of ligand and could be used for future direct C-H functionalizations. The utilization of norbornene type ligands for assistance in C-H activation processes has opened a new window for future molecular design using direct C-H functionalization strategies.

  8. The 2-alkyl-2H-indazole regioisomers of synthetic cannabinoids AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA are possible manufacturing impurities with cannabimimetic activities

    OpenAIRE

    Longworth, Mitchell; Banister, Samuel D.; Mack, James B. C.; Glass, Michelle; Connor, Mark; Kassiou, Michael

    2016-01-01

    Indazole-derived synthetic cannabinoids (SCs) featuring an alkyl substituent at the 1-position and l-valinamide at the 3-carboxamide position (e.g., AB-CHMINACA) have been identified by forensic chemists around the world, and are associated with serious adverse health effects. Regioisomerism is possible for indazole SCs, with the 2-alkyl-2H-indazole regioisomer of AB-CHMINACA recently identified in SC products in Japan. It is unknown whether this regiosiomer represents a manufacturing impurit...

  9. Alkylation sensitivity screens reveal a conserved cross-species functionome

    Science.gov (United States)

    Svilar, David; Dyavaiah, Madhu; Brown, Ashley R.; Tang, Jiang-bo; Li, Jianfeng; McDonald, Peter R.; Shun, Tong Ying; Braganza, Andrea; Wang, Xiao-hong; Maniar, Salony; St Croix, Claudette M.; Lazo, John S.; Pollack, Ian F.; Begley, Thomas J.; Sobol, Robert W.

    2013-01-01

    To identify genes that contribute to chemotherapy resistance in glioblastoma, we conducted a synthetic lethal screen in a chemotherapy-resistant glioblastoma derived cell line with the clinical alkylator temozolomide (TMZ) and an siRNA library tailored towards “druggable” targets. Select DNA repair genes in the screen were validated independently, confirming the DNA glycosylases UNG and MYH as well as MPG to be involved in the response to high dose TMZ. The involvement of UNG and MYH is likely the result of a TMZ-induced burst of reactive oxygen species. We then compared the human TMZ sensitizing genes identified in our screen with those previously identified from alkylator screens conducted in E. coli and S. cerevisiae. The conserved biological processes across all three species composes an Alkylation Functionome that includes many novel proteins not previously thought to impact alkylator resistance. This high-throughput screen, validation and cross-species analysis was then followed by a mechanistic analysis of two essential nodes: base excision repair (BER) DNA glycosylases (UNG, human and mag1, S. cerevisiae) and protein modification systems, including UBE3B and ICMT in human cells or pby1, lip22, stp22 and aim22 in S. cerevisiae. The conserved processes of BER and protein modification were dual targeted and yielded additive sensitization to alkylators in S. cerevisiae. In contrast, dual targeting of BER and protein modification genes in human cells did not increase sensitivity, suggesting an epistatic relationship. Importantly, these studies provide potential new targets to overcome alkylating agent resistance. PMID:23038810

  10. Itaconate is an anti-inflammatory metabolite that activates Nrf2 via alkylation of KEAP1.

    Science.gov (United States)

    Mills, Evanna L; Ryan, Dylan G; Prag, Hiran A; Dikovskaya, Dina; Menon, Deepthi; Zaslona, Zbigniew; Jedrychowski, Mark P; Costa, Ana S H; Higgins, Maureen; Hams, Emily; Szpyt, John; Runtsch, Marah C; King, Martin S; McGouran, Joanna F; Fischer, Roman; Kessler, Benedikt M; McGettrick, Anne F; Hughes, Mark M; Carroll, Richard G; Booty, Lee M; Knatko, Elena V; Meakin, Paul J; Ashford, Michael L J; Modis, Louise K; Brunori, Gino; Sévin, Daniel C; Fallon, Padraic G; Caldwell, Stuart T; Kunji, Edmund R S; Chouchani, Edward T; Frezza, Christian; Dinkova-Kostova, Albena T; Hartley, Richard C; Murphy, Michael P; O'Neill, Luke A

    2018-03-28

    The endogenous metabolite itaconate has recently emerged as a regulator of macrophage function, but its precise mechanism of action remains poorly understood. Here we show that itaconate is required for the activation of the anti-inflammatory transcription factor Nrf2 (also known as NFE2L2) by lipopolysaccharide in mouse and human macrophages. We find that itaconate directly modifies proteins via alkylation of cysteine residues. Itaconate alkylates cysteine residues 151, 257, 288, 273 and 297 on the protein KEAP1, enabling Nrf2 to increase the expression of downstream genes with anti-oxidant and anti-inflammatory capacities. The activation of Nrf2 is required for the anti-inflammatory action of itaconate. We describe the use of a new cell-permeable itaconate derivative, 4-octyl itaconate, which is protective against lipopolysaccharide-induced lethality in vivo and decreases cytokine production. We show that type I interferons boost the expression of Irg1 (also known as Acod1) and itaconate production. Furthermore, we find that itaconate production limits the type I interferon response, indicating a negative feedback loop that involves interferons and itaconate. Our findings demonstrate that itaconate is a crucial anti-inflammatory metabolite that acts via Nrf2 to limit inflammation and modulate type I interferons.

  11. Differential alkylation-based redox proteomics - Lessons learnt

    DEFF Research Database (Denmark)

    Wojdyla, Katarzyna; Rogowska-Wrzesinska, Adelina

    2015-01-01

    -sulfenylation are crucial mediators of intracellular redox signalling, with known associations to health and disease. Study of their functionalities has intensified thanks to the development of various analytical strategies, with particular contribution from differential alkylation-based proteomics methods. Presented here...... is a critical evaluation of differential alkylation-based strategies for the analysis of S-nitrosylation and S-sulfenylation. The aim is to assess the current status and to provide insights for future directions in the dynamically evolving field of redox proteomics. To achieve that we collected 35 original...

  12. Solid-Phase S-Alkylation Promoted by Molecular Sieves.

    Science.gov (United States)

    Calce, Enrica; Leone, Marilisa; Mercurio, Flavia Anna; Monfregola, Luca; De Luca, Stefania

    2015-11-20

    A solid-phase S-alkylation procedure to introduce chemical modification on the cysteine sulfhydryl group of a peptidyl resin is reported. The reaction is promoted by activated molecular sieves and consists of a solid-solid process, since both the catalyst and the substrate are in a solid state. The procedure was revealed to be efficient and versatile, particularly when used in combination with the solution S-alkylation approach, allowing for the introduction of different molecular diversities on the same peptide molecule.

  13. Synthesis and Characterization of 5-(hydrazino-alkyl) Tetrazoles

    Science.gov (United States)

    2014-07-01

    structure and 1H NMR spectrum of hydrazone 7 7 Synthesis of 5 - (hydrazino - alkyl) tetrazole via BOC hydrazine Amino acid- BOC Amino acid . HCl...Acidic medium Tetrazole-R-N2H2- BOC Acidic medium Tetrazole-R-N2H2 . HCl  Address solubility issues  Solid state structures of hydrochloride salt...hydrazino - alkyl) tetrazole via BOC hydrazine Removal of BOC protecting group 11, n = 1 12, n = 2 1H NMR and DSC of 5-(hydrazino-methyl)tetrazole

  14. Regeneration of zeolite catalysts of isobutane alkylation with butenes

    Energy Technology Data Exchange (ETDEWEB)

    Manza, I.A.; Tsupryk, I.N.; Bartyshevskii, V.A.; Gaponenko, O.I.; Petrilyak, K.I.

    1986-12-10

    The industrial adoption of alkylation of isoalkanes with alkenes is held back by the rapid and irreversible deactivation of the zeolite catalysts appropriate to the process. This paper is aimed specifically at the restoration of the catalytic activity and increase in the service life of zeolite alkylation catalysts. The catalyst chosen for the investigation was HLaCaNaX zeolite both unmodified and modified with various multivalence cations. The thermochemical and oxidative regeneration process as well as the equipment utilized are described. Both the advantages and the drawbacks of the method are given; explanations for the possibly irreversible losses of the catalytic properties in the regenerated zeolites are also put forward.

  15. Isobutane/2-butene alkylation with zeolite Y without BrÆnsted acidity

    OpenAIRE

    Rosenbach Jr, Nilton; Mota, Claudio J. A.

    2005-01-01

    Alkylation of isobutane with 2-butene was performed on metal-exchanged Y zeolites, using an alkylchloride as carbocation initiator. The results indicated that, compared with a protonic zeolite, the deactivation was significantly slower and the production of trimethylpentanes was higher on the metal-exchanged zeolites. The metal cations act as Lewis acids, interacting with the chloride initiating the carbocationic reactions. The results also support the view that protonic sites on the catalyst...

  16. Experimental studies on toxicity of ethylene glycol alkyl ethers in Japan.

    OpenAIRE

    Nagano, K; Nakayama, E; Oobayashi, H; Nishizawa, T; Okuda, H; Yamazaki, K

    1984-01-01

    Past studies on the toxicological effects of ethylene glycol alkyl ethers as well as the recent data on these chemicals in Japan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratogenicity of ethylene glycol dimethyl ether (EGdM). Studies on ethylene glycol alkyl ethers and related...

  17. Thermogravimetric control of intermediate compounds in uranium metallurgy

    International Nuclear Information System (INIS)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-01-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

  18. Enzymatic Analysis of G- and V-Agents and Their Degradation Products

    National Research Council Canada - National Science Library

    Elashvili, Ilya

    2003-01-01

    .... The nerve agents can be hydrolyzed to their respective methylphosphonate alkyl ester (h-agent) products by alkali treatment or by specific hydrolytic enzymes, such as organophosphorus hydrolase...

  19. Formation of coumarines during the degradation of alkyl substituted aromatic oil components by the yeast Trichosporon asahii.

    Science.gov (United States)

    Awe, Susanne; Mikolasch, Annett; Schauer, Frieder

    2009-10-01

    In this study, we investigated the ability of the yeast Trichosporon asahii SBUG-Y 833 to assimilate phenylalkanes with alkyl chain lengths from 7 to 12 carbon atoms, and we describe for the first time the formation of coumarines via a novel degradation pathway other than the normal terminal and ss-oxidation pathway of the alkyl residues. Besides benzoic acid and its further oxidation products, six new metabolites were identified. These were the three coumarines--4-hydroxycoumarin, 4,6-dihydroxycoumarin, 4,8-dihydroxycoumarin-and the three alkyl substituted aromatic acids--7-phenylheptanoic acid, 2-hydroxyphenylheptanoic acid, and 2-hydroxyphenylpropanoic acid. 4-Hydroxycoumarin was the main extracellular metabolite during the degradation of both odd- and even-chain phenylalkanes and was also produced during further biotransformation of 2-hydroxyphenylpropanoic acid and trans-2-hydroxycinnamic acid. Due to the ability of T. asahii to form hydroxylated coumarines, the transformation of 7-hydroxycoumarin and 2,4-dihydroxyphenylpropanoic acid was investigated. Yeast cells supplemented with 7-hydroxycoumarin formed 6,7-dihydroxycoumarin and 4,7-dihydroxycoumarin. The transformation of 2,4-dihydroxyphenylpropanoic acid yielded to 4,7-dihydroxycoumarin as the main product. All hydroxylated coumarines were continuously accumulated and are very resistant to further oxidation. The high potential of the yeast T. asahii SBUG-Y 833 to form different hydroxylated coumarines from alkylaromatics suggests possible applications in the biotechnological production of coumarine structures with medical potential as anticoagulative and antitumor pharmaceutical.

  20. Immobilization of Lipases on Alkyl Silane Modified Magnetic Nanoparticles: Effect of Alkyl Chain Length on Enzyme Activity

    Science.gov (United States)

    Wang, Jiqian; Meng, Gang; Tao, Kai; Feng, Min; Zhao, Xiubo; Li, Zhen; Xu, Hai; Xia, Daohong; Lu, Jian R.

    2012-01-01

    Background Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. Methodology/Principal Findings Magnetite nanoparticles, prepared through a co-precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p-nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18) modified Fe3O4 were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. Conclusions/Significance The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for enzyme immobilization

  1. Immobilization of lipases on alkyl silane modified magnetic nanoparticles: effect of alkyl chain length on enzyme activity.

    Directory of Open Access Journals (Sweden)

    Jiqian Wang

    Full Text Available BACKGROUND: Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. METHODOLOGY/PRINCIPAL FINDINGS: Magnetite nanoparticles, prepared through a co-precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p-nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18 modified Fe(3O(4 were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. CONCLUSIONS/SIGNIFICANCE: The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for

  2. Immobilization of lipases on alkyl silane modified magnetic nanoparticles: effect of alkyl chain length on enzyme activity.

    Science.gov (United States)

    Wang, Jiqian; Meng, Gang; Tao, Kai; Feng, Min; Zhao, Xiubo; Li, Zhen; Xu, Hai; Xia, Daohong; Lu, Jian R

    2012-01-01

    Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. Magnetite nanoparticles, prepared through a co-precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p-nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18) modified Fe(3)O(4) were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for enzyme immobilization enabling efficient enzyme recovery and recycling.

  3. Mechanism of carbon-halogen bond reductive cleavage in activated alkyl halide initiators relevant to living radical polymerization: theoretical and experimental study.

    Science.gov (United States)

    Isse, Abdirisak A; Gennaro, Armando; Lin, Ching Yeh; Hodgson, Jennifer L; Coote, Michelle L; Guliashvili, Tamaz

    2011-04-27

    The mechanism of reductive cleavage of model alkyl halides (methyl 2-bromoisobutyrate, methyl 2-bromopropionate, and 1-bromo-1-chloroethane), used as initiators in living radical polymerization (LRP), has been investigated in acetonitrile using both experimental and computational methods. Both theoretical and experimental investigations have revealed that dissociative electron transfer to these alkyl halides proceeds exclusively via a concerted rather than stepwise manner. The reductive cleavage of all three alkyl halides requires a substantial activation barrier stemming mainly from the breaking C-X bond. The activation step during single electron transfer LRP (SET-LRP) was originally proposed to proceed via formation and decomposition of RX(•-) through an outer sphere electron transfer (OSET) process (Guliashvili, T.; Percec, V. J. Polym. Sci., Part A: Polym. Chem. 2007, 45, 1607). These radical anion intermediates were proposed to decompose via heterolytic rather than homolytic C-X bond dissociation. Here it is presented that injection of one electron into RX produces only a weakly associated charge-induced donor-acceptor type radical anion complex without any significant covalent σ type bond character between carbon-centered radical and associated anion leaving group. Therefore, neither homolytic nor heterolytic bond dissociation applies to the reductive cleavage of C-X in these alkyl halides inasmuch as a true radical anion does not form in the process. In addition, the whole mechanism of SET-LRP has to be revisited since it is based on presumed OSET involving intermediate RX(•-), which is shown here to be nonexistent.

  4. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

  5. 40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

  6. 40 CFR 721.10143 - Amines, bis (C11-14-branched and linear alkyl).

    Science.gov (United States)

    2010-07-01

    ... linear alkyl). 721.10143 Section 721.10143 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10143 Amines, bis (C11-14-branched and linear alkyl). (a) Chemical..., bis (C11-14-branched and linear alkyl) (PMN P-06-733; CAS No. 900169-60-0) is subject to reporting...

  7. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

  8. 40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

    Science.gov (United States)

    2010-07-01

    ..., alkali and amine salts. 721.2565 Section 721.2565 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

  9. Gravity with Intermediate Goods Trade

    Directory of Open Access Journals (Sweden)

    Sujin Jang

    2017-12-01

    Full Text Available This paper derives the gravity equation with intermediate goods trade. We extend a standard monopolistic competition model to incorporate intermediate goods trade, and show that the gravity equation with intermediates trade is identical to the one without it except in that gross output should be used as the output measure instead of value added. We also show that the output elasticity of trade is significantly underestimated when value added is used as the output measure. This implies that with the conventional gravity equation, the contribution of output growth can be substantially underestimated and the role of trade costs reduction can be exaggerated in explaining trade expansion, as we demonstrate for the case of Korea's trade growth between 1995 and 2007.

  10. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer...... transmission to their bird definitive host by predation. In experimental infections, we found an intensity-dependent establishment success, with a decrease in the success rate of cercariae developing into infective metacercariae with an increasing dose of cercariae applied to each amphipod. In natural...... the two species. Our results thus indicate that the infracommunity of larval helminths in their intermediate host is interactive and that any density-dependent effect in the intermediate host may have lasting effects on individual parasite fitness....

  11. Hydrogen-Bond Directed Regioselective Pd-Catalyzed Asymmetric Allylic Alkylation: The Construction of Chiral α-Amino Acids with Vicinal Tertiary and Quaternary Stereocenters.

    Science.gov (United States)

    Wei, Xuan; Liu, Delong; An, Qianjin; Zhang, Wanbin

    2015-12-04

    A Pd-catalyzed asymmetric allylic alkylation of azlactones with 4-arylvinyl-1,3-dioxolan-2-ones was developed, providing "branched" chiral α-amino acids with vicinal tertiary and quaternary stereocenters, in high yields and with excellent selectivities. Mechanistic studies revealed that the formation of a hydrogen bond between the Pd-allylic complex and azlactone isomer is responsible for the excellent regioselectivities. This asymmetric alkylation can be carried out on a gram scale without a loss of catalytic efficiency, and the resulting product can be further transformed to a chiral azetidine in two simple steps.

  12. Asymmetric Synthesis of N-Boc-(R)-Silaproline via Rh-Catalyzed Intramolecular Hydrosilylation of Dehydroalanine and Continuous Flow N-Alkylation.

    Science.gov (United States)

    Chung, John Y L; Shevlin, Michael; Klapars, Artis; Journet, Michel

    2016-04-15

    An asymmetric synthesis of a silicon-containing proline surrogate, N-Boc-(R)-silaproline (1), is described. Starting from N-Boc-dehydroalanine ester, deprotonation, followed by N-alkylation with chloromethyldimethylsilane under flow conditions, afforded the N-alkylated product 8 in 91% yield. An unprecedented enantioselective (NBD)2RhBF4/Josiphos 404-1 catalyzed 5-endo-trig hydrosilylation afforded the silaproline ester in 85-90% yield and >95% ee. Subsequent saponification and salt formation upgraded 1 to >99% ee.

  13. Radiolabeled n-substituted-6-iodo-3, 14-dihydroxy-4, 5alpha-epoxymorphinans, intermediates for producing the same, and a process for the preparation and methods of detecting opioid receptors

    Energy Technology Data Exchange (ETDEWEB)

    de Costa, B.R.; Iadarola, M.J.; Rothman, R.B.; Berman, K.F.; Rice, K.C.

    1991-01-01

    The invention is directed to radiolabeled N-substituted-6-iodo-3,14-dihydroxy-4,5 alpha-epoxymorphinans, intermediates for producing the same, and a process for the preparation and methods of detecting opioid receptors, wherein Iodo is selected from the group consisting of (123)I and (125)I; and where the N substitution is alkyl, cycloalkylloweralkyl or allyl.

  14. Discovery of a Marine Bacterium Producing 4-Hydroxybenzoate and Its Alkyl Esters, Parabens

    Science.gov (United States)

    Peng, Xue; Adachi, Kyoko; Chen, Choryu; Kasai, Hiroaki; Kanoh, Kaneo; Shizuri, Yoshikazu; Misawa, Norihiko

    2006-01-01

    Chemically synthesized 4-hydroxybenzoate (4HBA) is widely used in the chemical and electrical industries as a material for producing polymers such as those of the liquid crystal type. Its alkyl esters, called parabens, have been the most widely used preservatives by the food and cosmetic industries. We report here for the first time a microorganism, a marine bacterium, which biosynthesizes these petrochemical products. The marine bacterial strain, A4B-17, which was found to belong to the genus Microbulbifer on the basis of its rRNA and gyrB sequences, was isolated from an ascidian in the coastal waters of Palau. Strain A4B-17 was, surprisingly, found to produce 10 mg/liter of 4HBA, together with its butyl (24 mg/liter), heptyl (0.4 mg/liter), and nonyl (6 mg/liter) esters. We therefore characterized 23 other marine bacteria belonging to the genus Microbulbifer, which our institute had previously isolated from various marine environments, and found that these bacteria also produced 4HBA, although with low production levels (less than one-fifth of that produced by A4B-17). We also show that the alkyl esters of 4HBA produced by strain A4B-17 were effective in preventing the growth of yeasts, molds, and gram-positive bacteria. PMID:16885309

  15. Yield and organoleptic characteristics of Suya (an intermediate ...

    African Journals Online (AJOL)

    High cost of choice meat used in suya production makes the product an exclusive meat for the rich. In order to make suya (an intermediate moisture meat) available and affordable to the common man thereby increasing their animal protein intake, this experiment therefore become imperative. Meat from the ...

  16. Synthesis of 1-alkyl triazolium triflate room temperature ionic liquids ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 9. Synthesis of 1-alkyl triazolium triflate room temperature ionic liquids and their catalytic studies in multi-component Biginelli reaction. Sankaranarayanan Nagarajan Tanveer M Shaikh Elango Kandasamy. Volume 127 Issue 9 September 2015 pp 1539- ...

  17. Ionic liquid containing hydroxamate and N-alkyl sulfamate ions

    Science.gov (United States)

    Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

    2016-03-15

    Embodiments of the invention are related to ionic liquids and more specifically to ionic liquids used in electrochemical metal-air cells in which the ionic liquid includes a cation and an anion selected from hydroxamate and/or N-alkyl sulfamate anions.

  18. Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence

    DEFF Research Database (Denmark)

    Hammerum, Steen

    2009-01-01

    , and gives rise to pronounced shifts of IR stretching frequencies and to increased absorption intensities. The hydrogen bond acceptor properties of alkyl radicals equal those of many conventional acceptors, e.g., the bond length changes and IR red-shifts suggest that tert-butyl radicals are slightly better...

  19. A new route alpha-alkyl-alpha-fluoromethylenebisphosphonates

    Czech Academy of Sciences Publication Activity Database

    Beier, Petr; Opekar, Stanislav; Zibinsky, M.; Bychinskaya, I.; Prakash, G. K. S.

    2011-01-01

    Roč. 9, č. 11 (2011), s. 4035-4038 ISSN 1477-0520 R&D Projects: GA ČR GP203/08/P310 Institutional research plan: CEZ:AV0Z40550506 Keywords : fluorine * phosphonate * alkylation Subject RIV: CC - Organic Chemistry Impact factor: 3.696, year: 2011

  20. A Green Alternative to Aluminum Chloride Alkylation of Xylene

    Science.gov (United States)

    Sereda, Grigoriy A.; Rajpara, Vikul B.

    2007-01-01

    An acutely less toxic 2-bromobutane is used to develop a simple graphite-promoted procedure of alkylation of p-xylene. It is further demonstrated that aluminum chloride is not required, the need for aqueous workup is eliminated, waste solutions are not produced and the multiple use of the catalyst is allowed.