WorldWideScience

Sample records for azides

  1. Sodium Azide

    Science.gov (United States)

    ... Matters What's New A - Z Index Facts About Sodium Azide What sodium azide is Sodium azide is a rapidly acting, ... give people sufficient warning of the danger. Where sodium azide is found and how it is used ...

  2. Silicone azide fireproof material

    Science.gov (United States)

    1978-01-01

    Finely powdered titanium oxide was added to silicone azide as the sintering agent to produce a nonflammable material. Mixing proportions, physical properties, and chemical composition of the fireproofing material are included.

  3. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10-6, 10-5, 10-4 and 10-3M) of sodium azide (NaN3) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M2

  4. Preparation analysis and physical characterisation of silver azide

    International Nuclear Information System (INIS)

    Industrially acceptable silver azide is obtainable in a free flowing crystal form by synthesis in an alkaline medium while using sodium carboxy methyl cellulose as a surface active agent. The silver azide was identified by means of X-ray diffraction and its purity was determined by means of a modified Heraeus nitrogen analyzer. Physical properties namely melting point, thermal sensitivity and reactivity were examined by means of differential thermal analysis and thermal stability using thermogravimetric analysis. The silver azide, unlike the lead azide, exhibited remarkable chemical stability when subjected to a high degree of humidity for six months, it showed no change while lead azide had completely decomposed after only four months exposure to the same conditions. Again silver azide, unlike lead azide showed itself to be chemically stable when exposed to the atmosphere even in the presence of a metal such as copper. The crystal modified silver azide exhibits, unlike what is generally accepted, impact and friction sensitivity values comparable to those of lead azide (98 % pure). The impact sensitivity is similar to that of lead azide (98 % pure) but is slightly more friction sensitive. The investigation into the explosive properties of silver azide shows it to be more sensitive to electrical stimuli and react faster on a heated bridgewire than lead azide. It exhibits the same ignition properties as lead azide and is therefore ideally suited for use in modern military electric detonators

  5. In situ Fabrication of Monolithic Copper Azide

    Science.gov (United States)

    Li, Bing; Li, Mingyu; Zeng, Qingxuan; Wu, Xingyu

    2016-04-01

    Fabrication and characterization of monolithic copper azide were performed. The monolithic nanoporous copper (NPC) with interconnected pores and nanoparticles was prepared by decomposition and sintering of the ultrafine copper oxalate. The preferable monolithic NPC can be obtained through decomposition and sintering at 400°C for 30 min. Then, the available monolithic NPC was in situ reacted with the gaseous HN3 for 24 h and the monolithic NPC was transformed into monolithic copper azide. Additionally, the copper particles prepared by electrodeposition were also reacted with the gaseous HN3 under uniform conditions as a comparison. The fabricated monolithic copper azide was characterized by Fourier transform infrared (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and differential scanning calorimetry (DSC).

  6. Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

    Directory of Open Access Journals (Sweden)

    Johan C. Brandt

    2009-06-01

    Full Text Available Aromatic aldehydes have been converted into the corresponding carbamoyl azides using iodine azide. These reactions have been performed safely under continuous flow reaction conditions in microreactors.

  7. The azide radical and its reaction with tryptophan and tyrosine

    International Nuclear Information System (INIS)

    Azide radicals react with azide ions according to N3 + N3- N6-, K = 0.33 dm3 mol-1. The species N6- has an absorption maximum at 645 nm epsilon = 6600 dm3 mol-1 cm-1. The reaction between the azide radical and ferrocyanide at an azide concentration of 0.05 mol dm-3 is independent of ionic strength, showing that N3 is the reacting form of the radical. From the reduction potentials of the azide radical and tryptophan, azide radicals can react with tryptophan by electron transfer. Reaction of azide radicals with tyrosine can also proceed by electron transfer. Whereas the formation of the tryptophan radical cation can be demonstrated in the reaction of Br2- with tryptophan, its formation could not be observed directly in the reaction of N3 with tryptophan because the azide ion deprotonates the tryptophan radical cation at high concentrations of azide. Reactions are proposed to account for observations made in previous pulse radiolysis studies of solutions containing azide and tryptophan or tyrosine. (author)

  8. Towards the Synthesis of Graphene Azide from Graphene Oxide

    OpenAIRE

    Halbig, Christian E.; Philipp Rietsch; Siegfried Eigler

    2015-01-01

    In the last decades, organic azides haven proven to be very useful precursors in organic chemistry, for example in 1,3-dipolar cycloaddition reactions (click-chemistry). Likewise, azides can be introduced into graphene oxide with an almost intact carbon framework, namely oxo-functionalized graphene (oxo-G1), which is a highly oxidized graphene derivative and a powerful precursor for graphene that is suitable for electronic devices. The synthesis of a graphene derivative with exclusively azide...

  9. Radiation treatment effect on sensibility of lead azide

    International Nuclear Information System (INIS)

    One presents the results of the radiation treatment effect on probability of lead azide explosion. Dependence of explosion probability on preliminary irradiation dose is shown to be of nonmonotonic nature: growth in the field of low doses and drop under high doses. The obtained experimental results agree with a divacancy model of initiation of heavy metal azides

  10. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  11. Crystal structure determination of strontium and calcium azide

    Energy Technology Data Exchange (ETDEWEB)

    Krischner, H.; Kelz, G. (Technische Univ., Graz (Austria). Inst. fuer Physikalische und Theoretische Chemie)

    1982-11-01

    Crystal structures of strontium azide and calcium azide have been investigated by means of the X-ray powder method. Both compounds crystallize or orthorhombic in space group Fddd. Strontium and calcium are surrounded by eight terminal nitrogen atoms of different azide groups which form antiprisms. The azide groups are linear in Sr(N/sub 3/)/sub 2/ with distances of 118.2(12) pm but show a small deviation from linearity in Ca(N/sub 3/)/sub 2/ with distances of 116.9(15) pm. The final R-values are 0.080 for Sr(N/sub 3/)/sub 2/ and 0.067 for Ca(N/sub 3/)/sub 2/, respectively.

  12. Crystal structure determination of strontium and calcium azide

    International Nuclear Information System (INIS)

    Crystal structures of strontium azide and calcium azide have been investigated by means of the X-ray powder method. Both compounds crystallize or orthorhombic in space group Fddd. Strontium and calcium are surrounded by eight terminal nitrogen atoms of different azide groups which form antiprisms. The azide groups are linear in Sr(N3)2 with distances of 118.2(12) pm but show a small deviation from linearity in Ca(N3)2 with distances of 116.9(15) pm. The final R-values are 0.080 for Sr(N3)2 and 0.067 for Ca(N3)2, respectively. (author)

  13. [Reaction of 1,8-naphthyridine azides with ethyl acrylate].

    Science.gov (United States)

    Livi, O; Ferrarini, P L; Bertini, D; Tonetti, I

    1975-12-01

    The reaction of 1,8-naphthyridine azides with ethyl acrylate leads to the formation of 2-pyrazolines instead of 1,2,3-triazolines. Some of the compounds obtained have undergone pharmacological and microbiological (antibacterial) testing. PMID:1204828

  14. Synthesis of benzofuranyl and indolyl methyl azides by tandem silver-catalyzed cyclization and azidation.

    Science.gov (United States)

    Ranjith Kumar, Gadi; Kiran Kumar, Yalla; Kant, Ruchir; Sridhar Reddy, Maddi

    2016-04-26

    Ag(i)-catalyzed synthesis of 2-azidomethyl benzofurans/indoles from linear and readily available hydroxyl/amino-phenyl propargyl alcohols is described via a highly regioselective C-O and C-N bond formation. Control experiments reveal that the reaction involves the sequential Ag(i)-catalyzed 5-exo-dig cyclization and a catalyst free γ-allylic azidation. The synthetic utility of this method has been demonstrated by using the azidomethyl unit of the above synthesized heterocycles as the base for a variety of other functionalizations, such as triazole-, tetrazole-, amide-, amine-, and pyrido-derivatives. PMID:27064507

  15. Self-assembly of azide containing dipeptides.

    Science.gov (United States)

    Yuran, Sivan; Razvag, Yair; Das, Priyadip; Reches, Meital

    2014-07-01

    Functional structures and materials are formed spontaneously in nature through the process of self-assembly. Mimicking this process in vitro will lead to the formation of new substances that would impact many areas including energy production and storage, biomaterials and implants, and drug delivery. The considerable structural diversity of peptides makes them appealing building blocks for self-assembly in vitro. This paper describes the self-assembly of three aromatic dipeptides containing an azide moiety: H-Phe(4-azido)-Phe(4-azido)-OH, H-Phe(4-azido)-Phe-OH, and H-Phe-Phe(4-azido)-OH. The peptide H-Phe(4-azido)-Phe(4-azido)-OH self-assembled into porous spherical structures, whereas the peptides H-Phe(4-azido)-Phe-OH and H-Phe-Phe(4-azido)-OH did not form any ordered structures under the examined experimental conditions. The azido group of the peptide can serve as a photo cross-linking agent upon irradiation with UV light. To examine the effect of this group and its activity on the self-assembled structures, we irradiated the assemblies in solution for different time periods. Using electron microscopy, we determined that the porous spherical assemblies formed by the peptide H-Phe(4-azido)-Phe(4-azido)-OH underwent a structural change upon irradiation. In addition, using FT-IR, we detected the chemical change of the peptide azido group. Moreover, using indentation experiments with atomic force microscopy, we showed that the Young's modulus of the spherical assemblies increased after 20 min of irradiation with UV light. Overall, irradiating the solution of the peptide assemblies containing the azido group resulted in a change both in the morphology and mechanical properties of the peptide-based structures. These ordered assemblies or their peptide monomer building blocks can potentially be incorporated into other peptide assemblies to generate stiffer and more stable materials. PMID:24889029

  16. Applications of Azide-Based Bioorthogonal Click Chemistry in Glycobiology

    Directory of Open Access Journals (Sweden)

    Xiu Zhang

    2013-06-01

    Full Text Available Click chemistry is a powerful chemical reaction with excellent bioorthogonality features: biocompatible, rapid and highly specific in biological environments. For glycobiology, bioorthogonal click chemistry has created a new method for glycan non-invasive imaging in living systems, selective metabolic engineering, and offered an elite chemical handle for biological manipulation and glycomics studies. Especially the [3 + 2] dipolar cycloadditions of azides with strained alkynes and the Staudinger ligation of azides and triarylphosphines have been widely used among the extant click reactions. This review focuses on the azide-based bioorthogonal click chemistry, describing the characteristics and development of these reactions, introducing some recent applications in glycobiology research, especially in glycan metabolic engineering, including glycan non-invasive imaging, glycomics studies and viral surface manipulation for drug discovery as well as other applications like activity-based protein profiling and carbohydrate microarrays.

  17. Azide- and alkyne-derivatised α-amino acids

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Pedersen, D.S.

    2012-01-01

    With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way for their...... synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention to...... unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...

  18. A practical one-pot synthesis of azides directly from alcohols

    Indian Academy of Sciences (India)

    Lalthazuala Rokhum; Ghanashyam Bez

    2012-05-01

    Alkyl/benzyl azides can be readily synthesized in excellent yields from their corresponding alcohols by stirring a solution of sodium azide in DMSO with a thoroughly ground equimolecular mixture of triphenylphosphine, iodine and imidazole.

  19. Perfluroaryl azides : Reactivities, Unique Reactions and their Applications in the Synthesis of Theranostic Agents

    OpenAIRE

    Xie, Sheng

    2015-01-01

    The work centersaround perfluoroaryl azides (PFAAs), and theirability to undergo certain fast and robusttransformations. The chemistry was furtherappliedfor biomedical applications. The first section focuses on the azide-aldehyde-amine cycloaddition using PFAAs. Experimental and computational investigations uncovered a fast azide-enamine cycloaddition to form triazolines, which spontaneously rearrange into stable amidine products. In addition, this transformation was explored in the formulati...

  20. Cyanogen Azide. Ionization Potentials and Ab Initio SCF MO Calculation

    DEFF Research Database (Denmark)

    Bak, Börge; Jansen, Peter; Stafast, Herbert

    1975-01-01

    The Ne(I) and He(I) photoelectron(PE) spectra of cyanogen azide, NCN3, have been recorded at high resolution. Their interpretation is achieved by comparison with the PE spectrum of HN3 and an ab initio LCGO SCF MO calculation. Deviations from Koopmans' theorem of quite different magnitudes are fo...

  1. Inorganic or organic azide-containing hypergolic ionic liquids.

    Science.gov (United States)

    Joo, Young-Hyuk; Gao, Haixiang; Zhang, Yanqiang; Shreeve, Jean'ne M

    2010-04-01

    Recently extensive research has focused on replacing toxic hydrazine, monomethylhydrazine, and unsymmetrical dimethylhydrazine as liquid propellant fuels. 2-Azido-N,N-dimethylethylamine (1) is a good candidate to replace hydrazine derivatives in certain hypergolic fuel applications. Energetic ionic liquids that contain the 2-azido-N,N,N-trimethylethylammonium cation with nitrocyanamide, dicyanamide, dinitramide, or azide anion have been successfully synthesized in good yields by metathesis reactions. Ionic liquids have received considerable attention as energetic materials. The replacement of hydrazine with tertiary ammonium salts is especially attractive since many ionic liquids are models for green chemistry. In this work, new azide-functionalized ionic liquids are demonstrated to exhibit hypergolic activity with such oxidizers as 100% nitric acid or nitrogen tetraoxide (NTO). PMID:20175509

  2. Azidated Ether-Butadiene-Ether Block Copolymers as Binders for Solid Propellants

    Science.gov (United States)

    Cappello, Miriam; Lamia, Pietro; Mura, Claudio; Polacco, Giovanni; Filippi, Sara

    2016-07-01

    Polymeric binders for solid propellants are usually based on hydroxyl-terminated polybutadiene (HTPB), which does not contribute to the overall energy output. Azidic polyethers represent an interesting alternative but may have poorer mechanical properties. Polybutadiene-polyether copolymers may combine the advantages of both. Four different ether-butadiene-ether triblock copolymers were prepared and azidated starting from halogenated and/or tosylated monomers using HTPB as initiator. The presence of the butadiene block complicates the azidation step and reduces the storage stability of the azidic polymer. Nevertheless, the procedure allows modifying the binder properties by varying the type and lengths of the energetic blocks.

  3. Base-promoted reactions of bridged ketones and 1,3- and 1,4-haloalkyl azides: competitive alkylation vs azidation reactions of ketone enolates.

    Science.gov (United States)

    Yao, Lei; Smith, Brenton T; Aubé, Jeffrey

    2004-03-01

    The reactions of 1,3- and 1,4-haloalkyl azides with enolates of 2-norbornanone (and a ring-expanded analog) afford polycyclic 1,2,3-triazolines in good yields. The reaction occurs by the initial azidation of the ketone enolate, followed in order by triazoline formation and O-alkylation. An interesting element of this process is the preferential reaction of the alkyl azide with an enolate anion as opposed to the more familiar reaction of the alkyl halide (including Cl and I derivatives). Reactions of acyclic or monocyclic enolates generally lead to 1,2,3-triazoles but none of the alternative C-alkylation product. PMID:14987033

  4. Evolving Structural Diversity and Metallicity in Compressed Lithium Azide

    KAUST Repository

    Prasad, Dasari L. V. K.

    2013-10-10

    In pursuit of new stable nitrogen-rich phases and of a possible insulator-metal transition, the ground-state electronic structure of lithium azide, LiN3, is investigated from 1 atm to 300 GPa (∼2-fold compression) using evolutionary crystal structure exploration methods coupled with density functional theoretical calculations. Two new LiN3 phases, containing slightly reduced and well-separated N2 units, are found to be enthalpically competitive with the known lithium azide crystal structure at 1 atm. At pressures above 36 GPa nitrogen-rich assemblies begin to evolve. These incorporate NN bond formation beyond that in N2 or N3 -. N6 rings and infinite one-dimensional linear nitrogen chains (structural analogues to polyacetylene) appear. Above 200 GPa quasi-one- and two-dimensional extended puckered hexagonal and decagonal nitrogen layers emerge. The high-pressure phase featuring linear chains may be quenchable to P = 1 atm. With increasing pressure the progression in electrical conductivity is from insulator to metal. © 2013 American Chemical Society.

  5. Polymerization of nitrogen in cesium azide under modest pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoli, E-mail: use126126@126.com, E-mail: lijianfu@lyu.edu.cn [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Beijing Computational Science Research Center, Beijing 100084 (China); State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); Li, Jianfu, E-mail: use126126@126.com, E-mail: lijianfu@lyu.edu.cn [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Zhu, Hongyang [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); Chen, Li [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Lin, Haiqing [Beijing Computational Science Research Center, Beijing 100084 (China)

    2014-07-28

    Alkali metal azides can be used as starting materials in the synthesis of polymeric nitrogen, a potential high-energy-density material. The structural evolutionary behaviors of nitrogen in CsN{sub 3} have been studied up to 200 GPa using particle swarm optimization structure search combining with density functional theory. Three stable new phases with C2/m, P2{sub 1}/m, and P-1 structure at pressure of 6, 13, and 51 GPa are identified for the first time. The phase transition to chain like structure (P-1 phase) occurs at a modest pressure 51 GPa, the azide ions N{sub 3}{sup −} (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN{sub 3} system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp{sup 2} hybridizations. Our study completes the structural evolution of CsN{sub 3} under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression.

  6. Polymerization of nitrogen in cesium azide under modest pressure

    International Nuclear Information System (INIS)

    Alkali metal azides can be used as starting materials in the synthesis of polymeric nitrogen, a potential high-energy-density material. The structural evolutionary behaviors of nitrogen in CsN3 have been studied up to 200 GPa using particle swarm optimization structure search combining with density functional theory. Three stable new phases with C2/m, P21/m, and P-1 structure at pressure of 6, 13, and 51 GPa are identified for the first time. The phase transition to chain like structure (P-1 phase) occurs at a modest pressure 51 GPa, the azide ions N3− (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN3 system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp2 hybridizations. Our study completes the structural evolution of CsN3 under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression

  7. Polarographic studies about indium (III) behaviour in aqueous media of sodium azide

    International Nuclear Information System (INIS)

    The present study shows some polarographic behavior of indium (III) in azide media that is close those observed in a thiocyanate solution. The presence of azide ligand decreases the overpotential in the discharge of indium whose catalytic character can be explained by formation of an azide bridge between electrode and indium (III) increasing the speed of electron transfer. The discharge of indium in azide media is diffusion controlled. As the azide concentration is increased the half wave potential displaces in the cathodic direction. This displacement is due to complex formation. The number of electrons, n, involved in the total process was estimates by the reversible polarographic equation to be 2,7. The potentiostatic coulometry of indium in azide/hydrazoic acid buffer showed a catalytic process where the chemistry regeneration was performed by reaction of hydrazoic acid and indium amalgam. The electrochemistry evidence was the constancy of current as the electrolysis proceeded. The chemistry aspect was the presence of ammonium cation in electrolysed solution. The catalytic process with chemistry regeneration and the formation of a bridge by azide could explain the higher value of current in azide media compared to perchlorate solution. (author)

  8. Reactions of Nitroso Hetero Diels-Alder Cycloadducts with Azides: Stereoselective Formation of Triazolines and Aziridines

    Science.gov (United States)

    Bodnar, Brian S.

    2011-01-01

    The addition of azides to acylnitroso hetero Diels-Alder cycloadducts derived from cyclopentadiene affords exo triazolines in excellent yield. The reaction is greatly affected by reducing the level of alkene strain, while sterically demanding azides do not hinder the reaction. Conversion of the triazolines to aziridines is also described. PMID:17429998

  9. Reactions of nitroso hetero-Diels-Alder cycloadducts with azides: stereoselective formation of triazolines and aziridines.

    Science.gov (United States)

    Bodnar, Brian S; Miller, Marvin J

    2007-05-11

    The addition of azides to acylnitroso hetero-Diels-Alder cycloadducts derived from cyclopentadiene affords exo-triazolines in excellent yield. The reaction is greatly affected by the level of alkene strain, while sterically demanding azides do not hinder the reaction. Conversion of the triazolines to aziridines is also described. PMID:17429998

  10. 1,3-Dipolar cycloaddition reactivities of perfluorinated aryl azides with enamines and strained dipolarophiles.

    Science.gov (United States)

    Xie, Sheng; Lopez, Steven A; Ramström, Olof; Yan, Mingdi; Houk, K N

    2015-03-01

    The reactivities of enamines and predistorted (strained) dipolarophiles toward perfluoroaryl azides (PFAAs) were explored experimentally and computationally. Kinetic analyses indicate that PFAAs undergo (3 + 2) cycloadditions with enamines up to 4 orders of magnitude faster than phenyl azide reacts with these dipolarophiles. DFT calculations were used to identify the origin of this rate acceleration. Orbital interactions between the cycloaddends are larger due to the relatively low-lying LUMO of PFAAs. The triazolines resulting from PFAA-enamine cycloadditions rearrange to amidines at room temperature, while (3 + 2) cycloadditions of enamines and phenyl azide yield stable, isolable triazolines. The 1,3-dipolar cycloadditions of norbornene and DIBAC also show increased reactivity toward PFAAs over phenyl azide but are slower than enamine-azide cycloadditions. PMID:25553488

  11. The counteracting effect of potassium cyanide in sodium azide-inhibited germination of Paulownia tomentosa  Steud. seeds

    OpenAIRE

    Živković Suzana; Grubišić Dragoljub V.; Giba Zlatko; Konjević Radomir

    2005-01-01

    The effect of some respiratory inhibitors on light-induced Paulownia tomentosa Steud. seed germination was studied. Millimolar solution of sodium azide was sufficient to completely prevent germination induced by a 5-min red light pulse. The inhibitory effect of azide was absent if seeds were rinsed before phytochrome activation by light. Sodium azide was effective only if present in the period of Pfr activity. The escape time from azide inhibition compared to the escape from far-red light act...

  12. Synthesis and spectra of N-15 labelled phenyl azides

    International Nuclear Information System (INIS)

    A method permitting a stepwise introduction of nitrogen atoms without isolation of intermediate compounds was chosen for the preparation of 15-N labelled phenyl azides: C6H5NH2 ->(a, b) -> C6H5-N=N=N where a Na15NO2, HCl, b = Ts15NH2/NaOH. GC-MS investigation demonstrated the high purity and confirmed the identity of all isotopomers Ph-N3, Ph-15N=N=N, Ph-N=15N=N, Ph-N=N=15N and allowed us to propose the MS fragmentation patterns. 15N NMR spectra gave evidence that no rearrangement of the nitrogen atom in the azido group took place during the synthesis

  13. Inactivation of Chikungunya virus by 1,5 iodonapthyl azide

    Directory of Open Access Journals (Sweden)

    Sharma Anuj

    2012-12-01

    Full Text Available Abstract Background Chikungunya virus (CHIKV is an arthropod borne alphavirus of the family Togaviridae. CHIKV is a reemerging virus for which there is no safe prophylactic vaccine. A live attenuated strain of CHIKV, CHIK181/25, was previously demonstrated to be highly immunogenic in humans, however, it showed residual virulence causing transient arthralgia. Findings In this study, we demonstrate the complete inactivation of CHIKV181/25 by 1,5 iodonapthyl azide (INA. No cytopathic effect and virus replication was observed in cells infected with the INA-inactivated CHIKV. However, a reduction in the INA-inactivated CHIK virus-antibody binding capacity was observed by western blot analysis. Conclusion INA completely inactivated CHIKV and can further be explored for developing an inactivated-CHIKV vaccine.

  14. Effects of sodium azide on the abundance of prokaryotes and viruses in marine samples.

    Directory of Open Access Journals (Sweden)

    Christian Winter

    Full Text Available Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For that we conducted incubation experiments with untreated and sodium azide treated marine water samples at 4°C and room temperature. The data indicate that sodium azide cannot be used to maintain marine samples used for the enumeration of prokaryotes and viruses.

  15. 1,3-Dipolar Cycloaddition Reactivities of Perfluorinated Aryl Azides with Enamines and Strained Dipolarophiles

    OpenAIRE

    Xie, Sheng; Lopez, Steven A.; Ramström, Olof; Yan, Mingdi; Houk, K. N.

    2015-01-01

    The reactivities of enamines and predistorted (strained) dipolarophiles toward perfluoroaryl azides (PFAAs) were explored experimentally and computationally. Kinetic analyses indicate that PFAAs undergo (3 + 2) cycloadditions with enamines up to 4 orders of magnitude faster than phenyl azide reacts with these dipolarophiles. DFT calculations were used to identify the origin of this rate acceleration. Orbital interactions between the cycloaddends are larger due to the relatively low-lying LUMO...

  16. Accelerating Strain-Promoted Azide-Alkyne Cycloaddition Using Micellar Catalysis.

    Science.gov (United States)

    Anderton, Grant I; Bangerter, Alyssa S; Davis, Tyson C; Feng, Zhiyuan; Furtak, Aric J; Larsen, Jared O; Scroggin, Triniti L; Heemstra, Jennifer M

    2015-08-19

    Bioorthogonal conjugation reactions such as strain-promoted azide-alkyne cycloaddition (SPAAC) have become increasingly popular in recent years, as they enable site-specific labeling of complex biomolecules. However, despite a number of improvements to cyclooctyne design, reaction rates for SPAAC remain significantly lower than those of the related copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Here we explore micellar catalysis as a means to increase reaction rate between a cyclooctyne and hydrophobic azide. We find that anionic and cationic surfactants provide the most efficient catalysis, with rate enhancements of up to 179-fold for reaction of benzyl azide with DIBAC cyclooctyne. Additionally, we find that the presence of surfactant can provide up to 51-fold selectivity for reaction with a hydrophobic over hydrophilic azide. A more modest, but still substantial, 11-fold rate enhancement is observed for micellar catalysis of the reaction between benzyl azide and a DIBAC-functionalized DNA sequence, demonstrating that micellar catalysis can be successfully applied to hydrophilic biomolecules. Together, these results demonstrate that micellar catalysis can provide higher conjugation yields in reduced time when using hydrophobic SPAAC reagents. PMID:26056848

  17. On the Mechanism of Copper(I)-Catalyzed Azide-Alkyne Cycloaddition.

    Science.gov (United States)

    Zhu, Lei; Brassard, Christopher J; Zhang, Xiaoguang; Guha, P M; Clark, Ronald J

    2016-06-01

    The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction regiospecifically produces 1,4-disubstituted-1,2,3-triazole molecules. This heterocycle formation chemistry has high tolerance to reaction conditions and substrate structures. Therefore, it has been practiced not only within, but also far beyond the area of heterocyclic chemistry. Herein, the mechanistic understanding of CuAAC is summarized, with a particular emphasis on the significance of copper/azide interactions. Our analysis concludes that the formation of the azide/copper(I) acetylide complex in the early stage of the reaction dictates the reaction rate. The subsequent triazole ring-formation step is fast and consequently possibly kinetically invisible. Therefore, structures of substrates and copper catalysts, as well as other reaction variables that are conducive to the formation of the copper/alkyne/azide ternary complex predisposed for cycloaddition would result in highly efficient CuAAC reactions. Specifically, terminal alkynes with relatively low pKa values and an inclination to engage in π-backbonding with copper(I), azides with ancillary copper-binding ligands (aka chelating azides), and copper catalysts that resist aggregation, balance redox activity with Lewis acidity, and allow for dinuclear cooperative catalysis are favored in CuAAC reactions. Brief discussions on the mechanistic aspects of internal alkyne-involved CuAAC reactions are also included, based on the relatively limited data that are available at this point. PMID:27216993

  18. Strain-Promoted 1,3-Dipolar Cycloaddition of Cycloalkynes and Organic Azides.

    Science.gov (United States)

    Dommerholt, Jan; Rutjes, Floris P J T; van Delft, Floris L

    2016-04-01

    A nearly forgotten reaction discovered more than 60 years ago-the cycloaddition of a cyclic alkyne and an organic azide, leading to an aromatic triazole-enjoys a remarkable popularity. Originally discovered out of pure chemical curiosity, and dusted off early this century as an efficient and clean bioconjugation tool, the usefulness of cyclooctyne-azide cycloaddition is now adopted in a wide range of fields of chemical science and beyond. Its ease of operation, broad solvent compatibility, 100 % atom efficiency, and the high stability of the resulting triazole product, just to name a few aspects, have catapulted this so-called strain-promoted azide-alkyne cycloaddition (SPAAC) right into the top-shelf of the toolbox of chemical biologists, material scientists, biotechnologists, medicinal chemists, and more. In this chapter, a brief historic overview of cycloalkynes is provided first, along with the main synthetic strategies to prepare cycloalkynes and their chemical reactivities. Core aspects of the strain-promoted reaction of cycloalkynes with azides are covered, as well as tools to achieve further reaction acceleration by means of modulation of cycloalkyne structure, nature of azide, and choice of solvent. PMID:27573141

  19. Effects of mutagen application of sodium azide and gamma radiation in rice seeds

    International Nuclear Information System (INIS)

    Effects of mutagen application of sodium azide and gamma radiation in rice seeds. Upland rice seeds, variety Dourado Precoce, were treated with gamma-rays and sodium azide(SA). Biological effects of these treatments were studied in the M1 and M2 generations. Survival number, seedling height, plant fertility and chlorophyill mutation frequencies based on mutations per 100 M1 panicles and mutants per 100 M2 seedlings were analysed. Among these characters, plant fertility was the most sensitive for mutagen treatments, and higher doses of gamma-rays or higher concentrations of sodium azide reduced significantly fertility of M1 plants. The same effect as increase of concentration of sodium azide was observed when the acidity of buffer solution was increased, or when seeds were pre-treated in distilled water. The maximum chlorophyll mutation frequencies were obtained in sodium azide treatments: 40.74% in the M1 panicles and 10.67% in the M2 seedlings, in comparison with the maximum frequenies in gamma-irradiation of 10.39% in the M1 panicles and 1.73% in the M2 seedlings. (Author)

  20. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    International Nuclear Information System (INIS)

    The trivalent uranium compound, (MeC5H4)3U(thf), serves as a one- or two-electron reducing agent towards azides, RN3. These reactions produce either the uranium(IV) azide, (MeC5H4)3UN3, or uranium(V) imides, (MeC5H4)3UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me3XN3, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph3XN3, the azide is produced when X = C or Sn. For Ph3-xCH3N3, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC6H4N3, only the imides are produced. The magnetic properties of uranium diimides, [(MeC5H4)3U]2(μ-NRN), were investigated. Several uranium(III) amines, (MeC5H4)3U(NH2R), were produced from (MeC5H4)3U(thf) and RNH2, and NH3 was found to be a better ligand towards (MeC5H4)3U than is PMe3

  1. A Double-Clicking Bis-Azide Fluorogenic Dye for Bioorthogonal Self-Labeling Peptide Tags.

    Science.gov (United States)

    Demeter, Orsolya; Fodor, Eszter A; Kállay, Mihály; Mező, Gábor; Németh, Krisztina; Szabó, Pál T; Kele, Péter

    2016-04-25

    Herein, we give the very first example for the development of a fluorogenic molecular probe that combines the two-point binding specificity of biarsenical-based dyes with the robustness of bioorthogonal click-chemistry. This proof-of-principle study reports on the synthesis and fluorogenic characterization of a new, double-quenched, bis-azide fluorogenic probe suitable for bioorthogonal two-point tagging of small peptide tags by double strain-promoted azide-alkyne cycloaddition. The presented probe exhibits remarkable increase in fluorescence intensity when reacted with bis-cyclooctynylated peptide sequences, which could also serve as possible self-labeling small peptide tag motifs. PMID:27010966

  2. An Updated Synthesis of the Diazo-Transfer Reagent Imidazole-1-sulfonyl Azide Hydrogen Sulfate.

    Science.gov (United States)

    Potter, Garrett T; Jayson, Gordon C; Miller, Gavin J; Gardiner, John M

    2016-04-15

    Imidazole-1-sulfonyl azide and salts thereof are valuable reagents for diazo-transfer reactions, most particularly conversion of primary amines to azides. The parent reagent and its HCl salt present stability and detonation risks, but the hydrogen sulfate salt is significantly more stable. An updated procedure for the large-scale synthesis of this salt avoids isolation or concentration of the parent compound or HCl salt and will facilitate the use of hydrogen sulfate salt as the reagent of choice for diazo transfer. PMID:26998999

  3. Asymmetric azidation-cycloaddition with open-chain peptide-based catalysts. A sequential enantioselective route to triazoles.

    Science.gov (United States)

    Guerin, David J; Miller, Scott J

    2002-03-13

    A family of beta-substituted histidine-containing peptides has been synthesized to probe the effect of noncovalent conformational rigidification on catalyst enantioselectivity. Unambiguous enhancement of enantioselectivity in the conjugate addition of azide to alpha,beta-unsaturated carboxylate derivatives has been achieved, enabling application to a sequential asymmetric azidation/cycloaddition for the synthesis of optically enriched triazoles and triazolines. PMID:11878965

  4. 49 CFR 173.182 - Barium azide-50 percent or more water wet.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or...

  5. Copper on Chitosan: A Recyclable Heterogeneous Catalyst for Azide-alkyne Cycloaddition Reactions in Water

    Science.gov (United States)

    Copper sulfate is immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with copper sulfate; the ensuing catalyst has been utilized for the azide-alkyne cycloaddition in aqueous media and it can be recycled and reused many time without loosing it...

  6. Biological and genetic effects of combined treatments of sodium azide, gamma rays and EMS in barley

    International Nuclear Information System (INIS)

    Dry seeds of diploid barley were subjected to mutagenic treatments of sodium azide, gamma rays and EMS alone or in combination. Damage (reduction in seedling height, plant height and fertility), the frequency of chimeras in the M1 generation, and the frequency of chlorophyll-deficient mutations as well as morphological mutations in the M2 generation induced by combined treatments were greater than those by either of the single treatments. Synergistic increase in the frequency of chimeras, chlorphyll-deficient mutations and morphological mutations were observed in both sodium azide post-irradiation treatments and pre-EMS treatments; interaction among the mutagens in the treatment combinations on M1 damage was generally subtractive. An 8- to 16-hr soaking period of irradiated seeds in distilled water prior to sodium azide treatment significantly increased chlorophyll mutation frequency, as compared to that from the non-soaking treatment. Damage and frequency of chimeras, chlorophyll mutations and morphological mutations were consistently reduced by the soaking treatment in sodium azide plus EMS treatments. (author)

  7. Health hazard evaluation report HETA 95-0023-2531, American Azide Corporation, Cedar City, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Esswein, E.; Trout, D.; Hales, T.

    1995-09-01

    In response to a confidential request, an investigation was begun into possible exposures to sodium-azide and hydrazoic-acid at the American Azide Corporation (SIC-5169), Cedar City, Utah. Personal breathing zone samples indicated that concentrations of sodium-azide ranged up to 1.7mg/m3. Hydrazoic-acid levels ranged up to 1.1 parts per million (ppm). Sodium-azide levels exceeded the NIOSH recommended exposure level (REL) of 0.3mg/m3 in 28% of the samples and hydrazoic-acid exceeded the REL of 0.1ppm in 14% of the samples. On one occasion the air sample taken inside a supplied air helmet showed a hydrazoic-acid level of 0.13ppm which was greater than the 0.05ppm level recorded from samples on the worker`s collar. The packaging and reblending operation appeared to be those in which workers were most at risk. Medical screening was performed on 11 workers, ten of whom reported headaches occurring in the production areas within 6 months of the evaluation. During that same time period, nine of the 11 reported low blood pressure episodes.

  8. Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones

    Directory of Open Access Journals (Sweden)

    Farhan R. Bou-Hamdan

    2011-08-01

    Full Text Available Photolysis of aryl azides to give nitrenes, and their subsequent rearrangement in the presence of water to give 3H-azepinones, is performed in continuous flow in a photoreactor constructed of fluorinated ethylene polymer (FEP tubing. Fine tuning of the reaction conditions using the flow reactor allowed minimization of secondary photochemical reactions.

  9. In situ generation of the Ohira-Bestmann Reagent from stable sulfonyl azide

    DEFF Research Database (Denmark)

    Jepsen, Tue Heesgaard; Kristensen, Jesper Langgaard

    2014-01-01

    We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a safe and scalable approach for the transformation of aldehydes into terminal alkynes...

  10. Synthesis of functionalized polyesters by the "click" copper-catalyzed alkyne-azide cycloaddition

    OpenAIRE

    Lecomte, Philippe; Riva, Raphaël; Jérôme, Christine

    2009-01-01

    The functionalization of aliphatic polyesters by the copper-mediated azide–alkyne Huisgen’s cycloaddition is very efficient under mild conditions, which prevents degradation from occurring. The implementation of this reaction requires the synthesis of aliphatic polyesters bearing pendant alkynes and azides, which can be carried out either by polycondensation or by ring-opening polymerization.

  11. Determination of azide impurity in sartans using reversed-phase HPLC with UV detection.

    Science.gov (United States)

    Gričar, Maja; Andrenšek, Samo

    2016-06-01

    A simple and robust, gradient HPLC method was developed for determination of azide ppm (μgg(-1)) levels in different sartans (irbesartan, candesartan, valsartan). The sartan was dissolved in 0.1M NaOH. Then pH was adjusted to 4.5 with 20% H3PO4 followed by dilution with water. Precipitated API was removed by filtration using 0.45μm membrane PVDF (Polyvinylidene Fluoride) membrane filter, and supernatant was analyzed by gradient elution HPLC at room temperature with Hydro RP HPLC 250×4.6mm, 4μm column and UV detection at 205nm. The best sensitivity was achieved by UV detection cell with 60mm optical path length: LOD 0.17μgg(-1) and LOQ 0.84μgg(-1) for azide. The USP requirement for maximum azide content in irbesartan is 10μgg(-1). The analytical method was validated as per International Conference on Harmonization (ICH) guidelines with respect to system precision, intraday precision (repeatability), intermediate precision (ruggedness), linearity, quantitation limit, detection limit, accuracy, standard and sample solution stability, robustness and selectivity/specificity. The method was linear in the range from LOQ (0.84μgg(-1)) to 101μgg(-1) of azide. The correlation coefficient was 0.9999 and bias on y-axis for 84μgg(-1) test concentration was 0.33%. The accuracy of the method was established based on the recovery obtained between 94.0% and 103.0% for azide. Standard and sample solutions were stable for at least 48h at room temperature and in refrigerator. The method was found to be robust for variation in column temperature (±5°C) and mobile phase flow rate (±0.2mLmin(-1)) and selective for anions such as bromide, nitrate, nitrite, formate and acetate. PMID:26999319

  12. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph{sub 3}XN{sub 3}, the azide is produced when X = C or Sn. For Ph{sub 3-x}CH{sub 3}N{sub 3}, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC{sub 6}H{sub 4}N{sub 3}, only the imides are produced. The magnetic properties of uranium diimides, ((MeC{sub 5}H{sub 4}){sub 3}U){sub 2}({mu}-NRN), were investigated. Several uranium(III) amines, (MeC{sub 5}H{sub 4}){sub 3}U(NH{sub 2}R), were produced from (MeC{sub 5}H{sub 4}){sub 3}U(thf) and RNH{sub 2}, and NH{sub 3} was found to be a better ligand towards (MeC{sub 5}H{sub 4}){sub 3}U than is PMe{sub 3}.

  13. Spectroscopic Studies of Azide compounds: Thermochemistry, Chemical Kinetics and Photodissociation Dynamics

    Science.gov (United States)

    Quinto Hernandez, Alfredo

    Some of the most difficult chemical systems, either to observe or produce in significant quantities, are polynitrogen molecules. One example of this type of molecules in the early stages of investigation is cyclic-N3, whose molecular geometry and promising technological applications have attracted our attention to define optimal experimental conditions for being photoproduced. High-resolution synchrotron-radiation-based Photoionization Mass Spectrometry (PIMS) was applied to study the dissociative photoionization of three azide precursors for cyclic-N3; chlorine azide (ClN3), hydrogen azide (HN3), and methyl azide (CH3N3). In our attempts to detect cyclic-N3, the thermochemistry derived in the PIMS studies stimulated our work to perform photodissociation dynamics experiments of CH3N3 at 193 nm using Photofragment Translational Spectroscopy (PTS) with electron impact (EI) detection under collision-free conditions, and chemical kinetic studies based on Infrared Spectroscopy (IR) in matrix-isolated ices formed from rare gases (Argon, Nitrogen and Xenon). PTS experiments lead us to derive the branching ratio between reactions CH 3+N3 (radical channel) vs CH3N+N2 (molecular channel), and to conclude that cyclic-N3 is the dominant product in the radical channel. In contrast, in the matrix isolation experiments we found no evidence of the radical channel, possibly due to barrier-less recombination. However, since no mechanistic reports of methyl azide dissociation exist at these conditions, these studies could have significant implications for future experiments addressed to detect cylic-N3 under matrix environments.

  14. The counteracting effect of potassium cyanide in sodium azide-inhibited germination of Paulownia tomentosa  Steud. seeds

    Directory of Open Access Journals (Sweden)

    Živković Suzana

    2005-01-01

    Full Text Available The effect of some respiratory inhibitors on light-induced Paulownia tomentosa Steud. seed germination was studied. Millimolar solution of sodium azide was sufficient to completely prevent germination induced by a 5-min red light pulse. The inhibitory effect of azide was absent if seeds were rinsed before phytochrome activation by light. Sodium azide was effective only if present in the period of Pfr activity. The escape time from azide inhibition compared to the escape from far-red light action, was delayed for about 24 hours. When azide was applied after phytochrome activation, its effect depended on how long it was present in the incubation medium. The removal of azide allowed full restoration of germination by another red light pulse and the far-red escape time did not differ from the escape of untreated, i.e. water-imbibed seeds. Potassium cyanide alone did not produce any effect in light-stimulated germination of these seeds. However, it counteracted the inhibitory effect of azide in light-stimulated germination, if applied simultaneously at a concentration three times higher.

  15. Physiological and mutagenic effects of sodium azide alone and in combination with gamma-rays on rice (Oryza sativa l.)

    International Nuclear Information System (INIS)

    Physiological and mutagenic effects of sodium azide alone and in combination with gamma-rays were studied in rice under laboratory and field conditions. The physiological damage and mutagenic effect of M2 were investigated. The results are as follows: 1. Sodium azide could induce physiological damage in M1 generation and mutations of chlorophyll, plant height and heading date in M2 generation. The damage and mutation frequencies increased with increasing concentrations of sodium azide. 2. Physiological and mutagenic effects were found to be pH dependent. In comparison with treatments at pH 7.0, sodium azide caused more M1 damage and induced more mutation in M2 at pH 3.0. 3. Sensitivity of rice to sodium azide increased after presoaking treatments. 24h-presoaking, howoever, could alleviate injury by sodium azide at pH 3.0. 4. Treatments of gamma-rays together with sodium azide resulted in increased M1 damage and M2 mutation frequencies, and the combinative effect was more conspicuous when azide was used at pH 3.0. An expanded mutation spectrum was also observed in the combined treatments. 5. Number of the initial cells in the embryo of main panicles was estimated to be 2—3, according to the segregation ratio of chlorophyll mutants in M2. The combined treatments of gamma-rays(15—30kR)together with so- dium azide(0.5—1mM)at pH 3.0 were recommended for rice mutation breeding programm. (author)

  16. 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.

  17. Comparison of physiological and genetic effects of gamma radiation and sodium azide on two rice (Oryza sativa, L.) genotypes

    International Nuclear Information System (INIS)

    The sensitivity of both genotypes (Oryzica 1 and Strain 30036) to gamma rays and sodium azide is studied. Doses of gamma-rays and concentrations of sodium azide were chosen so as to produce around 20%-25% height reduction in these genotypes. Emergence, survival and fertility were the physiological effects on M 1 generation analysed after the final treatment. The number of chlorophyll mutations and the number of seedling mutants were counted in M 2 generation. Taking into consideration, specially M 1 generation sterility, it was concluded that for the two genotypes studied, sodium azide presented a greater mutagen effect. (M.A.C.)

  18. Cellulose sulphuric acid as a biodegradable catalyst for conversion of aryl amines into azides at room temperature under mild conditions

    Indian Academy of Sciences (India)

    Firouzeh Nesmati; Ali Elhampour

    2012-07-01

    This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been converted into the corresponding aryl azides with 71-99% yields. The use of mild reaction conditions, avoids the use of harmful acids and toxic solvents and short reaction times are advantages of this methodology. The selected catalyst is found to be highly efficient and recyclable.

  19. Phase transitions of cesium azide at pressures up to 30 GPa studied using in situ Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, S. A., E-mail: medvedie@cpfs.mpg.de; Felser, C. [Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer-Str. 40, 01187 Dresden (Germany); Barkalov, O. I. [Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer-Str. 40, 01187 Dresden (Germany); Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Academician Ossipyan str. 2, Moscow District 142432 (Russian Federation); Naumov, P. [Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer-Str. 40, 01187 Dresden (Germany); Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskii prospekt 59, Moscow 119333 (Russian Federation); Palasyuk, T. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Evers, J.; Klapötke, T. M. [Energetic Materials Research, Ludwig-Maximilian University Munich (LMU), Butenandtstrasse 5-13(D), D-81377 Munich (Germany)

    2015-04-28

    Cesium azide has been studied by Raman spectroscopy at pressures up to ≈30 GPa at room temperature. The sequence of phase transitions to Phase III (at 0.5 GPa), Phase IV (at 4.3 GPa), and Phase V (at ≈19 GPa) has been observed in agreement with recent X-ray diffraction studies. Phase III has been found to adopt a monoclinic C2/m structure with two azide anions in nonequivalent positions, where one set of azide anions appears to be orientationally disordered according to the observed Raman spectra. The transition to Phase IV has been associated with orientational ordering of azide anions, while the transition to Phase V has been shown to proceed with a lowering of crystal symmetry. Moreover, spectroscopic features indicate a possible change of bonding in CsN{sub 3} toward formation of covalent bonds at high pressures.

  20. Direct C–H Azidation of Calix[4]arene as a Novel Method to Access Meta Substituted Derivatives

    Czech Academy of Sciences Publication Activity Database

    Stejskal, F.; Eigner, V.; Dvořáková, H.; Cuřínová, Petra; Lhoták, P.

    2015-01-01

    Roč. 56, č. 39 (2015), s. 5357-5361. ISSN 0040-4039 Institutional support: RVO:67985858 Keywords : calixarene * azidation * regionselectivity Subject RIV: CC - Organic Chemistry Impact factor: 2.379, year: 2014

  1. Quantum chemical treatment of cyanogen azide and its univalent and divalent ionic forms

    International Nuclear Information System (INIS)

    An explosive material, cyanogen azide (CN4) and its univalent and divalent anionic and cationic forms have been studied quantum chemically by using different theoretical approaches. In this study, the structures considered have been screened for their relative stabilities. Also, they have been investigated whether the charged forms play a role in the usual explosion process or any electrical charging during storage cause explosion. Various quantum chemical properties are obtained and discussed. It has been found that the univalent cation and anion and divalent cation formations do not cause much change in the molecular structure as compared to the neutral cyanogen azide molecule, whereas the divalent anionic form exhibits drastic changes in the geometry, resulting in bond cleavage to eliminate nitrogen molecule

  2. Azide-water intermolecular coupling measured by 2-color 2D IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Perakis F.

    2013-03-01

    Full Text Available We present 2-color two-dimensional infrared spectroscopy of intermolecular coupling between azide ions and their solvation shell water molecules. The cross-peak between azide asymmetric stretch vibration and the OD-stretch vibration is a result of low- probability uphill population transfer. Narrow bleach/excited state absorption peak shows selectivity to solvation shell water molecules only and the characteristics of the cross-peak suggest that the solvation shell hydrogen bond potential has similar anharmonic properties as the hydrogen bond in ice Ih. Population and depopulation of the excited state of the OD-stretch vibration happen on 150 fs and 1.7 ps timescales, respectively, with early manifesting heating effects that limit the selectivity to population times up to 1 ps.

  3. A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.

    Science.gov (United States)

    Zeghada, Sarah; Bentabed-Ababsa, Ghenia; Derdour, Aïcha; Abdelmounim, Safer; Domingo, Luis R; Sáez, José A; Roisnel, Thierry; Nassar, Ekhlass; Mongin, Florence

    2011-06-01

    Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities. PMID:21494704

  4. Polarographic stirring minima in the system indium (III) / sodium azide in DME

    International Nuclear Information System (INIS)

    Polarographic stirring minima in sodium azide and indium (III) was observed in DME. Microscopic observation of solution around the mercury drop showed movement of solution from bottom to up in the window of potential from - 1.0V to - 1.7V. The movement ceases in the presence of triton X-100 - 0.002% but the valley still remains. The depression of valley is pronounced in the presence of cations. (C.L.B.)

  5. 1,3-Dipolar Cycloaddition Reactions of Substituted Benzyl Azides with Acetylenic Compounds

    Directory of Open Access Journals (Sweden)

    Sultan T. Abu-Orabi

    2002-02-01

    Full Text Available We review in this article some of our work which has been published over the last fifteen years in the area of 1,3-dipolar cycloaddition reactions of substituted benzyl azides with acetylenic compounds to form the corresponding 1,2-3-triazoles. Several triazole derivatives were transformed into triazolopyridazine and triazolo-1,3,4-oxadiazole derivatives upon their reactions with hydrazine.

  6. Cyclization of Alkyne-Azide with Isonitrile/CO via Self-Relay Rhodium Catalysis.

    Science.gov (United States)

    Zhang, Zhen; Xiao, Fan; Huang, Baoliang; Hu, Jincheng; Fu, Bin; Zhang, Zhenhua

    2016-03-01

    A self-relay rhodium(I)-catalyzed cyclization of alkyne-azides with two σ-donor/π-acceptor ligands (isonitriles and CO) to form sequentially multiple-fused heterocycle systems via tandem nitrene transformation and aza-Pauson-Khand cyclization has been developed. In this approach, an intriguing chemoselective insertion process of isonitriles superior to CO was observed. This reaction provides an alternative strategy to synthesize functionalized pyrrolo[2,3-b]indole scaffolds. PMID:26907671

  7. Mixed azide-terminated monolayers: a platform for modifying electrode surfaces.

    Science.gov (United States)

    Collman, James P; Devaraj, Neal K; Eberspacher, Todd P A; Chidsey, Christopher E D

    2006-03-14

    We have prepared and characterized mixed self-assembled monolayers (SAM) on gold electrodes from azido alkane thiols and various omega-functionalized alkane thiols. In the presence of copper(I) catalysts, these azide-modified surfaces are shown to react rapidly and quantitatively with terminal acetylenes forming 1,2,3-triazoles, via "click" chemistry. The initial azide substituents can be identified and monitored using both grazing-angle infrared (IR) and X-ray photoelectron spectrosopies. Acetylenes possessing redox-active ferrocene substituents react with the azide-terminated mixed SAMs and electrochemical measurements of the ferrocene-modified SAM electrodes have been used to quantify the redox centers attached to these platforms. Time-resolved electrochemical measurements have enabled us to follow the formation of these ferrocene centers and thus to measure the rate of the surface "click" reaction. Under optimal conditions this well-behaved second-order reaction takes place with a rate constant of 1 x 10(3) M(-)(1) s(-)(1). Typical reaction times of several minutes were realized using micromolar concentrations of acetylene. These techniques have been used to construct well-characterized, covalently modified monolayers that can be employed as functional electrode surfaces. PMID:16519441

  8. Biocompatible Azide-Alkyne "Click" Reactions for Surface Decoration of Glyco-Engineered Cells.

    Science.gov (United States)

    Gutmann, Marcus; Memmel, Elisabeth; Braun, Alexandra C; Seibel, Jürgen; Meinel, Lorenz; Lühmann, Tessa

    2016-05-01

    Bio-orthogonal copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been widely used to modify azide- or alkyne-bearing monosaccharides on metabolic glyco-engineered mammalian cells. Here, we present a systematic study to elucidate the design space for the cytotoxic effects of the copper catalyst on NIH 3T3 fibroblasts and on HEK 293-F cells. Monitoring membrane integrity by flow cytometry and RT-PCR analysis with apoptotic and anti-apoptotic markers elucidated the general feasibility of CuAAC, with exposure time of the CuAAC reaction mixture having the major influence on biocompatibility. A high labeling efficiency of HEK 293-F cells with a fluorescent alkyne dye was rapidly achieved by CuAAC in comparison to copper free strain-promoted azide-alkyne cycloaddition (SPAAC). The study details effective and biocompatible conditions for CuAAC-based modification of glyco-engineered cells in comparison to its copper free alternative. PMID:26818821

  9. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  10. Synthesis and Luminescence Properties of Iridium(III Azide- and Triazole-Bisterpyridine Complexes

    Directory of Open Access Journals (Sweden)

    Timothy W. Schmidt

    2013-07-01

    Full Text Available We describe here the synthesis of azide-functionalised iridium(III bisterpyridines using the “chemistry on the complex” strategy. The resulting azide-complexes are then used in the copper(I-catalysed azide-alkyne Huisgen 1,3-dipolar cycloaddition “click chemistry” reaction to from the corresponding triazole-functionalised iridium(III bisterpyridines. The photophysical characteristics, including lifetimes, of these compounds were also investigated. Interestingly, oxygen appears to have very little effect on the lifetime of these complexes in aqueous solutions. Unexpectedly, sodium ascorbate acid appears to quench the luminescence of triazole-functionalised iridium(III bisterpyridines, but this effect can be reversed by the addition of copper(II sulfate, which is known to oxidize ascorbate under aerobic conditions. The results demonstrate that iridium(III bisterpyridines can be functionalized for use in “click chemistry” facilitating the use of these photophysically interesting complexes in the modification of polymers or surfaces, to highlight just two possible applications.

  11. Induced mutation in some guar (Cyamopsis tetragonoloba (L.) taub.) lines using gamma irradiation and sodium azide

    International Nuclear Information System (INIS)

    A mutagenesis study was carried on seeds of two lines of guar L 18 and L 14, which were bombarded with doses of 150, 300,450 and 600 Gy gamma irradiation. Part of the irradiated seeds with the dose 300 Gy and untreated seeds were then soaked separately in 40 or 80 mM of sodium azide for 20 or 30 hours and germinated in vitro to evaluate germination %. Another part of the irradiated seeds with 450 and 600 Gy, were then treated separately with 20 or 40 mM of sodium azide for 10 or 20 hours. Germination of guar was not affected by gamma doses. On the other hand, treatment with sodium azide alone had a great effect on the germination of guar. The percentage of germination ranged between 13.3 and 34.7%. High effects were obtained on seeds treated with 300 Gy and sodium azide (40 and 80 mM) for either 20 or 30 hours, which recorded a range between 9.3 and 13.3%. This indicated that the combined treatment with gamma rays and sodium azide were more effective than sole treatment. Gamma irradiation doses showed no effect on survival of M1 generation, while the combined treatments caused a reduction of about 81.3%. In M2 generation, the growth of the treated plants was slower than the control and the rate of growth decreased with the increased of dose. Variable chlorophyll abnormalities were also detected. In M3 generation leaves with varying chlorophyll abnormalities were recorded, deformated leaves and flowers were recorded at very low rates. However, the effect of gamma rays and the combined treatment on the both guar lines 14 and 18 compared to the control was recorded for the following parameters, inter node length, number of node main stem, number of branches, number of fertile branches, the height of the first pod, number of pods, number of seeds/pod, seed yield, pollen fertility and seed colour change. The most suitable doses that produce maximum variability were 450 Gy and 450 Gy/20 mM/20 hours in line 18 and 150 Gy and 450 Gy/40 mM/10 hours in line 14.(Author)

  12. Azide anions inhibit GH-18 endochitinase and GH-20 Exo β-N-acetylglucosaminidase from the marine bacterium Vibrio harveyi.

    Science.gov (United States)

    Sirimontree, Paknisa; Fukamizo, Tamo; Suginta, Wipa

    2016-02-01

    Vibrio harveyi is a bioluminescent marine bacterium that utilizes chitin as its sole source of energy. In the course of chitin degradation, the bacterium primarily secretes an endochitinase A (VhChiA) to hydrolyze chitin, generating chitooligosaccharide fragments that are readily transported into the cell and broken down to GlcNAc monomers by an exo β-N-acetylglucosaminidase (VhGlcNAcase). Here we report that sodium salts, especially sodium azide, inhibit two classes of these chitin-degrading enzymes (VhChiA and VhGlcNAcase) with distinct modes of action. Kinetic analysis of the enzymatic hydrolysis of pNP-glycoside substrates reveals that sodium azide inhibition of VhChiA has a mixed-type mode, but that it inhibits VhGlcNAcase competitively. We propose that azide anions inhibit chitinase activity by acting as strong nucleophiles that attack Cγ of the catalytic Glu or Cβ of the neighbouring Asp residues. Azide anions may bind not only to the catalytic centre, but also to the other subsites in the substrate-binding cleft of VhChiA. In contrast, azide anions may merely occupy the small-binding pocket of VhGlcNAcase, thereby blocking the accessibility of its active site by short-chain substrates. PMID:26330565

  13. Pressure-induced phase transitions in rubidium azide: Studied by in-situ x-ray diffraction

    International Nuclear Information System (INIS)

    We present the in-situ X-ray diffraction studies of RbN3 up to 42.0 GPa at room temperature to supplement the high pressure exploration of alkali azides. Two pressure-induced phase transitions of α-RbN3 → γ-RbN3 → δ-RbN3 were revealed at 6.5 and 16.0 GPa, respectively. During the phase transition of α-RbN3 → γ-RbN3, lattice symmetry decreases from a fourfold to a twofold axis accompanied by a rearrangement of azide anions. The γ-RbN3 was identified to be a monoclinic structure with C2/m space group. Upon further compression, an orthogonal arrangement of azide anions becomes energetically favorable for δ-RbN3. The compressibility of α-RbN3 is anisotropic due to the orientation of azide anions. The bulk modulus of α-RbN3 is 18.4 GPa, quite close to those of KN3 and CsN3. By comparing the phase transition pressures of alkali azides, their ionic character is found to play a key role in pressure-induced phase transitions.

  14. Pressure-induced phase transitions in rubidium azide: Studied by in-situ x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dongmei; Wu, Xiaoxin; Jiang, Junru; Zhang, Jian; Cui, Qiliang; Zhu, Hongyang, E-mail: hongyangzhu@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin 130012 (China); Wang, Xiaoli [State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin 130012 (China); Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China)

    2014-08-18

    We present the in-situ X-ray diffraction studies of RbN{sub 3} up to 42.0 GPa at room temperature to supplement the high pressure exploration of alkali azides. Two pressure-induced phase transitions of α-RbN{sub 3} → γ-RbN{sub 3} → δ-RbN{sub 3} were revealed at 6.5 and 16.0 GPa, respectively. During the phase transition of α-RbN{sub 3} → γ-RbN{sub 3}, lattice symmetry decreases from a fourfold to a twofold axis accompanied by a rearrangement of azide anions. The γ-RbN{sub 3} was identified to be a monoclinic structure with C2/m space group. Upon further compression, an orthogonal arrangement of azide anions becomes energetically favorable for δ-RbN{sub 3}. The compressibility of α-RbN{sub 3} is anisotropic due to the orientation of azide anions. The bulk modulus of α-RbN{sub 3} is 18.4 GPa, quite close to those of KN{sub 3} and CsN{sub 3}. By comparing the phase transition pressures of alkali azides, their ionic character is found to play a key role in pressure-induced phase transitions.

  15. Polymer immobilized Cu(I) formation and azide-alkyne cycloaddition: A one pot reaction

    OpenAIRE

    Islam, Rafique Ul; Taher, Abu; Choudhary, Meenakshi; Siwal, Samarjeet; Mallick, Kaushik

    2015-01-01

    During the polymerization of aniline using copper sulphate, act as an oxidizing agent, the in-situ synthesized Cu(I) ion catalyzed the cyclo-addition between azides and alkynes. This work represents the merging of two steps, synthesis of the catalyst and application of the catalyst, in a one pot reaction. The elimination of the separate catalyst synthesis step is economic in terms of cost and time. As aniline was used as one of the reactant components so there is no requirement to use additio...

  16. Azide- and Alkyne-Functionalised α- and β3-Amino Acids

    DEFF Research Database (Denmark)

    Sminia, T.J.; Pedersen, Daniel Sejer

    2012-01-01

    The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can be...... functionalised further, for example, through copper-catalysed Huisgen cycloaddition. Moreover, the corresponding α-amino acids 1 and 3 have been synthesised and characterised. All amino acid building blocks were of high optical purity as demonstrated by derivatisation and subsequent NMR analysis. © Georg Thieme...

  17. Azide-styrene resin negative deep UV resist for KrF excimer laser lithography

    International Nuclear Information System (INIS)

    The authors report a photosensitive composition, consisting of an aromatic azide compound (4,4'diazidodiphenyl methane) and a styrene resin (poly(styrene-co-maleic acid half-isoprapylate)), developed and evaluated as a negative deep ultra-violet (UV) resist for high-resolution KrF excimer laser lithography. Solubility of this resist in an aqueous developer decreases upon exposure to KrF excimer laser irradiation. The alkaline developer removes the unexposed areas of this resist. No swelling-induced pattern deformation occurs and high aspect ratio sub-half-micron patterns in 1.0 μm film thickness are obtained with high sensitivity

  18. Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

    OpenAIRE

    Hyunjoon Song; Byeong-Su Kim; Sungkyun Park; Ji Chan Park; Seongwan Jang; Aram Kim; Hyuntae Kang; Hyunje Woo; Kang Hyun Park

    2012-01-01

    Recent developments in the synthesis of CuO nanoparticles (NPs) and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC) nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalyt...

  19. A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.

    OpenAIRE

    Zeghada, Sarah; Bentabed-Ababsa, Ghenia; Derdour, Aïcha; Abdelmounim, Safer; Domingo, Luis .R.; Sáez, José A.; Roisnel, Thierry; Nassar, Ekhlass; Mongin, Florence

    2011-01-01

    Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of th...

  20. Metal azides under pressure: An emerging class of high energy density materials

    Indian Academy of Sciences (India)

    G Vaitheeswaran; K Ramesh Babu

    2012-11-01

    Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that of known high energetic materials. With this motive, in this present work, we try to address the high-pressure behaviour of LiN3 and KN3 by means of density functional calculations. All the calculations are performed with the inclusion of van derWaals interactions at semi empirical level, as these materials are typical molecular solids. We found that both LiN3 and KN3 are structurally stable up to the studied pressure range of 60 GPa and 16 GPa, respectively. At ambient conditions both the materials are insulators with a gap of 3.48 eV (LiN3) and 4.08 eV (KN3) and as pressure increases the band gap decreases and show semiconducting nature at high pressures.We also found that the compressibility of both the crystals is anisotropic which is in good agreement with experiment. Our theoretical study proved that the materials under study may have the ability to form polymeric nitrogen because of the decrease in interazide ion distance and possible overlapping of N atomic orbitals.

  1. Photoaffinity labeling of a bacterial sialidase with an aryl azide derivative of sialic acid

    International Nuclear Information System (INIS)

    A photoreactive radioiodinatable derivative of 2-deoxy-2,3-didehydro-5-N-acetylneuraminic acid (NeuAc2en), 5-N-acetyl-9-(4-azidosalicoylamido)-2-deoxy-2,3-didehydroneuram inic acid (ASA-NeuAc2-en) has been synthesized and used to label the active site of Clostridium perfringens sialidase. Like NeuAc2en, its aryl azide derivative is a strong competitive inhibitor of sialidase (Ki approximately 15 microM). The absorbance spectrum of ASA-NeuAc2en shows a characteristic aryl azide peak, which disappears upon photolysis with UV light. When its radioiodinated counterpart 5-N-acetyl-9-(4-iodoazidosalicoylamido)-2-deoxy-2,3-didehydrone uraminic acid ([125I]IASA-NeuAc2en) was photolyzed in the presence of C. perfringens sialidase a 72-kDa protein was labeled. Labeling occurred specifically in the active site since it was inhibited in the presence of NeuAc2en. Chemical cleavage of the photoaffinity-labeled 72-kDa protein demonstrates that specifically labeled peptides involved in the formation of the active site can easily be determined. ASA-NeuAc2en is a valuable new tool for the identification and structural/functional analysis of sialidases and other proteins, recognizing this sialic acid derivative

  2. Room Temperature Activation of Aryloxysulfonyl Azides by [Co(II)(TPP)] for Selective Radical Aziridination of Alkenes via Metalloradical Catalysis

    Science.gov (United States)

    Subbarayan, Velusamy; Jin, Li-Mei; Xin, Cui; Zhang, X. Peter

    2015-01-01

    Aryloxysulfonyl azides can be effectively activated by commercially available cobalt(II) complex of meso-tetraphenylporphyrin ([Co(TPP)]) at room temperature under neutral and nonoxidative conditions for selective radical aziridination of alkenes via metalloradical catalysis. The [Co(TPP)]-catalyzed radical aziridination system is suitable for different combinations of olefin substrates and aryloxysulfonyl azides, producing various N-aryloxysulfonyl aziridine derivatives in good to excellent yields. In addition to generating the environmentally benign N2 as the only byproduct, this Co(II)-based metalloradical aziridination process features mild reaction conditions and operational simplicity. PMID:26139944

  3. Blue-light activated rapid polymerization for defect-free bulk Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) crosslinked networks.

    Science.gov (United States)

    Shete, Abhishek U; El-Zaatari, Bassil M; French, Jonathan M; Kloxin, Christopher J

    2016-08-18

    A visible-light (470 nm wavelength) sensitive Type II photoinitiator system is developed for bulk Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions in crosslinked networks. The accelerated photopolymerization eliminates UV-mediated azide decomposition allowing for the formation of defect-free glassy networks which exhibit a narrow glass transition temperature. PMID:27499057

  4. A highly active and magnetically recoverable tris(triazolyl)-Cu(I) catalyst for alkyne-azide cycloaddition reactions.

    Science.gov (United States)

    Wang, Dong; Etienne, Laetitia; Echeverria, María; Moya, Sergio; Astruc, Didier

    2014-04-01

    Nanoparticle-supported tris(triazolyl)-CuBr, with a diameter of approximately 25 nm measured by TEM spectroscopy, has been easily prepared, and its catalytic activity was evaluated in the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. In initial experiments, 0.5 mol % loading successfully promoted the CuAAC reaction between benzyl azide and phenylacetylene, in water at room temperature (25 °C). During this process, the iron oxide nanoparticle-supported tris(triazolyl)-CuBr displayed good monodispersity, excellent recoverability, and outstanding reusability. Indeed, it was simply collected and separated from the reaction medium by using an external magnet, then used for another five catalytic cycles without significant loss of catalytic activity. Inductively coupled plasma (ICP) analysis for the first cycle revealed that the amount of copper leached from the catalyst into the reaction medium is negligible (1.5 ppm). The substrate scope has been examined, and it was found that the procedure can be successfully extended to various organic azides and alkynes and can also be applied to the one-pot synthesis of triazoles, through a cascade reaction involving benzyl bromides, alkynes, and sodium azide. In addition, the catalyst was shown to be an efficient CuAAC catalyst for the synthesis of allyl- and TEG-ended (TEG=triethylene glycol) 27-branch dendrimers. PMID:24574335

  5. MORPHOLOGICAL CHARACTERS OF CHILLI PEPPER (Capsicum frutescens L. AS INFLUENCED BY SODIUM AZIDE AT GENERATIVE STAGE OF M1 GENERATION

    Directory of Open Access Journals (Sweden)

    I Gusti Agung Eka Saraswati

    2013-04-01

    Full Text Available Chili pepper (Capsicum frutescens L. is one vegetable crop that has high economic value.  There are several problems in cultivation of chili pepper, for examples limited land, bad weather, and pests and diseases, which result in low production. These problems can be solved by developing new cultivar which has superior quality.  New cultivars of chili pepper plants can be obtained through induced mutation using chemical mutagen. In this research sodium azide (NaN3 was used as mutagen in chili pepper in order to obtain genetic variations that are useful in  increasing its  production.  The research was designed in  randomized  block  design. The observations were made on the response of plant morphology at generative stage, including plant height, number of branch, number of leaf, leaf length and leaf width.  The results showed that sodium azide increased plant height, branch number, leaf number and leaf length.  Sodium azide at concentrations of 2 mM and 5 mM were most effective in increasing plant height, number of leaves and number of branches. Keywords: Capsicum frutescens L., morphology, mutation, sodium azide

  6. A direct access to isoxazoles from ynones using trimethylsilyl azide as amino surrogate under metal/catalyst free conditions.

    Science.gov (United States)

    Kumar, Gadi Ranjith; Kumar, Yalla Kiran; Reddy, Maddi Sridhar

    2016-05-01

    A general method for isoxazoles from readily available ynones using trimethylsilyl azide as an amino surrogate, likely via an unprecedented hydroazidation of the alkyne and denitrogenative cyclization, is demonstrated. The method neither required any catalyst nor demanded unusual conditions to afford the products with outstanding functional group compatibility. PMID:27109700

  7. New potentiometric transducer based on a Mn(II) [2-formylquinoline thiosemicarbazone] complex for static and hydrodynamic assessment of azides.

    Science.gov (United States)

    Kamel, Ayman H

    2015-11-01

    A new potentiometric transducer for selective recognition of azide is characterized and developed. The PVC plasticized based sensor incorporates Mn(II) [2-formylquinoline thiosemicarbazone] complex in the presence of tri dodecyl methyl ammonium chloride (TDMAC) as a lipophilic cationic additive. The sensor displayed a near-Nernstian response for azide over 1.0×10(-2)-1.0×10(-5) mol L(-1), with an anionic slope of -55.8±0.6 mV decade(-1) and lower limit of detection 0.34 µg mL(-1). The sensor was pH independent in the range 5.5-9 and presented good selectivity features towards several inorganic anions, and it is easily used in a flow injection system and compared with a tubular detector. The intrinsic characteristics of the detector in a low dispersion manifold were determined and compared with data obtained under a hydrodynamic mode of operation. This simple and inexpensive automation, with a good potentiometric detector, enabled the analysis of ~33 samples h(-1) without requiring pre-treatment procedures. The proposed method is also applied to the analysis of trace levels of azide in primer mixtures. Significantly improved accuracy, precision, response time, stability and selectivity were offered by these simple and cost-effective potentiometric sensor compared with other standard techniques. The method has the requisite accuracy, sensitivity and precision to determine azide ions. PMID:26452931

  8. Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazoles...

  9. 1,3 Dipolar Cycloaddition Reactions of Substituted Benzyl Azides eith Tans-Dibenzoylethlene : Thermally Stable Trizoles Versus Unstable Triazolines

    International Nuclear Information System (INIS)

    Benzyl and Several Substituted benzyl azides Ιa-q reacted with trans -dibenzoylethylene 2 to give the thermaly unstable trizolinrs 3 which lose nitrogen molecule to yield either enamines 4 or enolimines 5. (Author's) 13 refs., 2 tabs., 4 strus., 1 sche., 2 figs

  10. Pressure and wall heat transfer behind a hydrogen/azide detonation wave in narrow tubes

    International Nuclear Information System (INIS)

    The reported study is concerned with the pressure evolution behind the detonation wave in tubes with an interior diameter in the range from 1 to 10 mm. Hydrogen azide in tubes with length-to-diameter ratios greater than 375 was detonated. The initial pressures were in the range from 1 to 20 Torr. The pressure behind the leading shock was measured with piezoelectrical transducers made of lead titanate and lead zirconate. It was found that the detonation velocity depends on wall heat losses. The wall heat flux observed behind the wave front was not in agreement with that calculated for constant flow parameters. In the diameter and pressure range considered, the wall heat flux varies strongly with tube diameter. This observation can be related to flow deviations regarding the Chapman-Jouguet parameters

  11. Electronic effects of ruthenium-catalyzed [3+2]-cycloaddition of alkynes and azides

    KAUST Repository

    Hou, Duenren

    2010-11-01

    A combined experimental and theoretical study of ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) reactions is presented and various electronic analyses were conducted to provide a basis in understanding the observed regioselectivity of the 1,2,3-triazole products. Computational studies using density functional theory (DFT) and atoms in molecules quantum theory (AIM) further yield fresh details on the electronic factors that determine the regioselectivity in the RuAAC. It is found that the formation of 1,2,3-triazole products is irreversible and from the Hammett study, the pathway involving a vinyl cationic intermediate is ruled out. The electronic effect favors the formation of 5-electron-donating-group substituted-1,2,3-trizoles. © 2010 Elsevier Ltd. All rights reserved.

  12. Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyunjoon Song

    2012-11-01

    Full Text Available Recent developments in the synthesis of CuO nanoparticles (NPs and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

  13. Rice improvement through mutation induction with gamma rays and sodium azide

    International Nuclear Information System (INIS)

    The objective of this research in rice (Oryza sativa L.) was to induce mutations for semidwarfism, early maturity, high yield potential and tolerance to Pyricularia grisea in the rice variety Pico Negro. Seeds were treated with sodium azide and gamma rays alone and in combination at various doses. In the M1 generation the number of chlorophyll deviations was recorded for the various treatments in order to select the optimum one, which proved to be 2.5 x 10-3 M NaN3 + 2.5 krad (25 Gy). In the M2 generation, mutations were obtained for morphological and chlorophyll characters, plant height, and earliness. The stability of the mutants selected in the M2 generation was confirmed in the M3 generation. A total of 148 mutants were selected. (author). 5 refs, 1 fig., 3 tabs

  14. Fused triazoles via tandem reactions of activated Cinchona alkaloids with azide ion. Second Cinchona rearrangement exemplified.

    Science.gov (United States)

    Röper, S; Franz, M H; Wartchow, R; Hoffmann, H M R

    2003-08-01

    [reaction: see text] Intramolecular 1,3-dipolar cycloadditions of cinchona azides to the C10-C11 alkyne and C10-C11 olefin unit of the alkaloid have been designed via tandem strategy. A variety of fused triazoles and triazolines with a bis-azahomotwistane skeleton have been prepared. In trifluoroethanol, O-mesylcinchonidine 7-OMs and NaN(3) furnish triazole 8 as well as cage-expanded 1,5-diazatricyclo[4.4.1.0(3,8)]undecane derivative 10. Both fused triazoles 8 and 10 are formed with retention of configuration at C9 and C3, respectively. 1-Azabicyclo[3.2.2]cage expansion is shown to be reversible. PMID:12889871

  15. Azide protection of bacteroides superoxide dismutases from inactivation by hydrogen peroxide

    International Nuclear Information System (INIS)

    The anaerobes Bacteroides fragilis, B. distasonis and B. thetaiotaomicron produce an iron-containing superoxide dismutase (FeSOD). These FeSODs are reversibly inhibited by 1 mM azide (NaN3) and are irreversibly inactivated upon incubation with hydrogen peroxide (H2O2). H2O2 inactivation of the enzyme likely depends on a Fenton type reaction with the production of hydroxyl radical (OH). Addition of NaN3 to the enzyme solution decreased the rate of inactivation by H2O2. After 20 minutes incubation of purified B. distasonis FeSOD with 2.5 mM H2O2, 61% of the initial enzymatic activity remained when 1 mM NaN3 was also present compared with 29% activity without NaN3. Similar results were seen with FeSOD from B. fragilis and B. thetaiotaomicron. Metal analyses of the native, peroxidized, and NaN3 protected samples are consistent with loss of Fe from the enzyme upon peroxidation, but retention of Fe and enzymatic activity in the NaN3 protected sample. Protection of FeSOD activity from H2O2 inactivation was dependent on NaN3 concentration. Anionic hydroxyl radical scavengers, such as urate and xanthine did not significantly protect the enzyme. The results are consistent with binding of azide to the active site either preventing entry of H2O2 or altering Fe redox potential, preventing OH production

  16. Synthesis of Dendronized Poly(l-Glutamate via Azide-Alkyne Click Chemistry

    Directory of Open Access Journals (Sweden)

    Peter Perdih

    2016-03-01

    Full Text Available Poly(l-glutamate (PGlu was modified with a second-generation dendron to obtain the dendronized polyglutamate, P(Glu-D. Synthesized P(Glu-D exhibited a degree of polymerization (DPn of 46 and a 43% degree of dendronization. Perfect agreement was found between the P(Glu-D expected structure and the results of nuclear magnetic resonance spectroscopy (NMR and size-exclusion chromatography coupled to a multi-angle light-scattering detector (SEC-MALS analysis. The PGlu precursor was modified by coupling with a bifunctional building block (N3-Pr-NH2 in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl-4-methylmorpholinium chloride (DMTMM coupling reagent. The second-generation polyamide dendron was prepared by a stepwise procedure involving the coupling of propargylamine to the l-lysine carboxyl group, followed by attaching the protected 2,2-bis(methylolpropionic acid (bis-MPA building block to the l-lysine amino groups. The hydroxyl groups of the resulting second-generation dendron were quantitatively deprotected under mild acidic conditions. The deprotected dendron with an acetylene focal group was coupled to the pendant azide groups of the modified linear copolypeptide, P(Glu-N3, in a Cu(I catalyzed azide-alkyne cycloaddition reaction to form a 1,4-disubstituted triazole. The dendronization reaction proceeded quantitatively in 48 hours in aqueous medium as confirmed by 1H NMR and Fourier transform infrared spectroscopy (FT-IR spectroscopy.

  17. Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions

    Directory of Open Access Journals (Sweden)

    Lukas Kupracz

    2011-10-01

    Full Text Available The multistep flow synthesis of vinyl azides and their application in the synthesis of vinyltriazoles is reported. The synthesis relies on a stable polymer-bound equivalent of iodine azide that serves to carry out 1,2-functionalization of alkenes in a telescope flow protocol. The intermediate 2-iodo azides are subjected to a DBU-mediated polymer-supported elimination step yielding vinyl azides in good yield. The third step involves the formation of vinyl triazoles by a copper-catalyzed Huisgen-"click" cycloaddition. The required heat is generated by electromagnetic induction based on copper. Copper serves both as heatable as well as catalytically active packed-bed material inside the flow reactor.

  18. Efficient synthesis of functionalized 1,2,3-triazoles by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide

    International Nuclear Information System (INIS)

    A simple and efficient protocol has been developed for the synthesis of 1,2,3-triazole derivatives by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide under mild conditions (author)

  19. Metal-catalysed azidation of tertiary C-H bonds suitable for late-stage functionalization

    Science.gov (United States)

    Sharma, Ankit; Hartwig, John F.

    2015-01-01

    Many enzymes oxidize unactivated aliphatic C-H bonds selectively to form alcohols; however, biological systems do not possess enzymes that catalyse the analogous aminations of C-H bonds. The absence of such enzymes limits the discovery of potential medicinal candidates because nitrogen-containing groups are crucial to the biological activity of therapeutic agents and clinically useful natural products. In one prominent example illustrating the importance of incorporating nitrogen-based functionality, the conversion of the ketone of erythromycin to the -N(Me)CH2- group in azithromycin leads to a compound that can be dosed once daily with a shorter treatment time. For such reasons, synthetic chemists have sought catalysts that directly convert C-H bonds to C-N bonds. Most currently used catalysts for C-H bond amination are ill suited to the intermolecular functionalization of complex molecules because they require excess substrate or directing groups, harsh reaction conditions, weak or acidic C-H bonds, or reagents containing specialized groups on the nitrogen atom. Among C-H bond amination reactions, those forming a C-N bond at a tertiary alkyl group would be particularly valuable, because this linkage is difficult to form from ketones or alcohols that might be created in a biosynthetic pathway by oxidation. Here we report a mild, selective, iron-catalysed azidation of tertiary C-H bonds that occurs without excess of the valuable substrate. The reaction tolerates aqueous environments and is suitable for the functionalization of complex structures in the late stages of a multistep synthesis. Moreover, this azidation makes it possible to install a range of nitrogen-based functional groups, including those from Huisgen `click' cycloadditions and the Staudinger ligation. We anticipate that these reactions will create opportunities to modify natural products, their precursors and their derivatives to produce analogues that contain different polarity and charge as a

  20. Gamma ray, EMS and sodium azide induced effectiveness and efficiency of chlorophyll mutations in basmati rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    The effectiveness and efficiency of gamma ray, EMS, sodium azide alone or in combination in relation to chlorophyll mutations in two varieties of Basmati rice (Oryza sativa L.) in M2 generation were studied. The chlorophyll mutations were induced by all the doses of mutagens alone or in combination relatively at a fair frequency in both the varieties in M2 generation. In general, it was found that combination treatments of gamma rays and EMS were observed to be more efficient in Taraori Basmati, while EMS alone and combination treatment of gamma rays and EMS were more efficient in Pusa Basmati 1 on sterility and growth injury basis both. Sodium azide at 0.5 mM was found as the most effective dose in both Taraori Basmati and Pusa Basmati 1 cultivars. (author)

  1. Carboxylate-Assisted Iridium-Catalyzed C-H Amination of Arenes with Biologically Relevant Alkyl Azides.

    Science.gov (United States)

    Zhang, Tao; Hu, Xuejiao; Wang, Zhen; Yang, Tiantian; Sun, Hao; Li, Guigen; Lu, Hongjian

    2016-02-24

    An iridium-catalyzed C-H amination of arenes with a wide substrate scope is reported. Benzamides with electron-donating and -withdrawing groups and linear, branched, and cyclic alkyl azides are all applicable. Cesium carboxylate is crucial for both reactivity and regioselectivity of the reactions. Many biologically relevant molecules, such as amino acid, peptide, steroid, sugar, and thymidine derivatives can be introduced to arenes with high yields and 100 % chiral retention. PMID:26712274

  2. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim

    2011-11-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering. © 2011 Elsevier Ltd. All rights reserved.

  3. Alkyne-Azide Cycloaddition Catalyzed by Silver Chloride and “Abnormal” Silver N-Heterocyclic Carbene Complex

    Directory of Open Access Journals (Sweden)

    Aldo I. Ortega-Arizmendi

    2013-01-01

    Full Text Available A library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of silver chloride instead of copper compounds. In addition, a novel “abnormal” silver N-heterocyclic carbene complex was tested as catalyst in this process. The results suggest that the reaction requires only 0.5% of silver complex, affording 1,2,3-triazoles in good yields.

  4. Kinetics and mechanism of the sulfite-induced autoxidation of cobalt(II) in aqueous azide medium

    Energy Technology Data Exchange (ETDEWEB)

    Coichev, N.; Van Eldik, R. (Univ. of Witten, Herdecke (West Germany))

    1991-05-15

    The autoxidation of Co(II) in azide medium is accelerated by sulfur(IV) oxides at a concentration level of 10{sup {minus}5} M. The formation of Co(III) was followed spectrophotometrically under the following conditions: (Co(II)) = 5 {times} 10{sup {minus}4} M; initial (Co(III)) = (0{minus}3.6) {times} 10{sup {minus}5} M; (total S(IV)) = (1{minus}4) {times} 10{sup {minus}5} M; 4 < pH < 6; (total N{sub 3}{sup {minus}}) = 0.1 {minus} 0.5 M; temperature = 25C; ionic strength = 1.0 M. The autoxidation reaction exhibits typical autocatalytic behavior in which the induction period depends on the Co(III) concentration. A detailed kinetic study of both the autoxidation step and the reduction of Co(III) by sulfur(IV) oxides demonstrates that the same rate-determining step is operative in both cases. This step involves the reduction of Co(III) by sulfur(IV) oxide to produce the SO{sub 3}{sup {minus}} radical, which reacts with dissolved oxygen to produce SO{sub 5}{sup {minus}} and rapidly oxidizes Co(II) in at least two consecutive steps. The observed rate constant depends on the pH and azide concentration, since these control the speciation of the sulfur(IV) oxides and cobalt (II/III) azide complexes. The proposed mechanism is discussed in reference to available literature information. 29 refs., 8 figs.

  5. Ab initio molecular orbital characterization of dimethyl group-III azides as sources for photolytic production of free radical beams

    International Nuclear Information System (INIS)

    Use of a beam of biradicaloid such as dialkyl group-III nitrene produced by the method of photodissociation of energetic compound beams (PDECB) is expected to be advantageous to the low-temperature thin-film growth of stoichiometric group-III nitride. Through the clarification of fundamental processes involved in pyrolysis as well as photolysis of dimethylgallium azide [(CH3)2GaN3], dimethylaluminum azide [(CH3)2AlN3], and dimethylboron azide [(CH3)2BN3] based on post-self-consistent field ab initio molecular orbital methods, we discuss the suitability of these possible source compounds for the production of beams of dimethylgalliumnitrene [(CH3)2GaN], dimethylaluminumnitrene [(CH3)2AlN], and dimethylboronnitrene [(CH3)2BN] by the PDECB method. The theoretical results suggested that (CH3)2GaN3 is a promising PDECB source material in that this molecule possesses the nature of unimolecular metastable dye

  6. Antifouling coatings based on covalently cross-linked agarose film via thermal azide-alkyne cycloaddition.

    Science.gov (United States)

    Xu, Li Qun; Pranantyo, Dicky; Neoh, Koon-Gee; Kang, En-Tang; Teo, Serena Lay-Ming; Fu, Guo Dong

    2016-05-01

    Coatings based on thin films of agarose-poly(ethylene glycol) (Agr-PEG) cross-linked systems are developed as environmentally-friendly and fouling-resistant marine coatings. The Agr-PEG cross-linked systems were prepared via thermal azide-alkyne cycloaddition (AAC) using azido-functionalized Agr (AgrAz) and activated alkynyl-containing poly(2-propiolamidoethyl methacrylate-co-poly(ethylene glycol)methyl ether methacrylate) P(PEMA-co-PEGMEMA) random copolymers as the precursors. The Agr-PEG cross-linked systems were further deposited onto a SS surface, pre-functionalized with an alkynyl-containing biomimetic anchor, dopamine propiolamide, to form a thin film after thermal treatment. The thin film-coated SS surfaces can effectively reduce the adhesion of marine algae and the settlement of barnacle cyprids. Upon covalent cross-linking, the covalently cross-linked Agr-PEG films coated SS surfaces exhibit good stability in flowing artificial seawater, and enhanced resistance to the settlement of barnacle cyprids, in comparison to that of the surfaces coated with physically cross-linked AgrAz films. PMID:26836479

  7. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation

    KAUST Repository

    Du, Naiying

    2011-03-11

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O 2/N 2 and CO 2/N 2 gas pairs, as well as for condensable gases, such as CO 2/CH 4, propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO 2 plasticization up to 20 atm pressure of pure CO 2 and CO 2/CH 4 mixtures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Many-body effects in the optical absorption of lithium azide (LiN3)

    Science.gov (United States)

    Gordienko, A. B.; Filippov, S. I.

    2016-07-01

    Until recently most of the understanding achieved for solid explosives has been obtained using various semi-empirical approaches due to a major role of excitonic effects in the mechanisms of decomposition. Nevertheless, during the last two decades, thanks to the ongoing progress in iterative computational methods, the inclusion of the electron-hole interaction in ab initio calculations has become a standard approach in solid-state theory. In this paper, the electronic structure and optical properties of bulk lithium azide are investigated, taking into account the electron-hole interaction via the Bethe-Salpeter equation (BSE). Here, we employ the kernel polynomial method (KPM), which significantly reduces the computational cost compared to direct diagonalization methods. The calculations of the imaginary part of the polarization dependent dielectric function including excitonic effects are reported for the first time. Then, we show a density map of the two-particle wave function and propose an alternative interpretation of the initial stages of the externally triggered chemical decomposition, based on the analysis of two-particle states near the absorption edge.

  9. MORPHOLOGICAL CHARACTERS OF CHILLI PEPPER (Capsicum frutescens L.) AS INFLUENCED BY SODIUM AZIDE AT GENERATIVE STAGE OF M1 GENERATION

    OpenAIRE

    I Gusti Agung Eka Saraswati; Made Pharmawati; I Ketut Junitha

    2013-01-01

    Chili pepper (Capsicum frutescens L.) is one vegetable crop that has high economic value.  There are several problems in cultivation of chili pepper, for examples limited land, bad weather, and pests and diseases, which result in low production. These problems can be solved by developing new cultivar which has superior quality.  New cultivars of chili pepper plants can be obtained through induced mutation using chemical mutagen. In this research sodium azide (NaN3) was used as mutagen in chi...

  10. Crosslinking of Kapok Cellulose Fiber via Azide Alkyne Click Chemistry as a New Material for Filtering System: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Nur Syazwani Abd Rahman

    2016-01-01

    Full Text Available A new class of green material has been elaborated by grafting the modified kapok fiber, by the means of azidated kapok fiber followed by “click-chemistry” reaction with the terminal alkyne crosslinker. The modified and synthesized product was characterized using Fourier transform infrared spectroscopy (FT-IR, and Scanning electron microscopy (SEM. The study also was undertaken to investigate the effect on the absorption of methylene blue from aqueous solution onto the click fiber prepared. The findings showed that the click kapok absorbed more compared to the untreated kapok. Based on the result, the reaction of click chemistry influenced the properties of the filter made from kapok fiber.

  11. Chromosomal induced aberrations in sunflower (Helianthus annuus L.) with gamma-irradiation, sodium azide and combined treatments

    International Nuclear Information System (INIS)

    The seeds of 2 varieties of common Sunflower (Helianthus annuus L.) viz: USH-430 and KL-675 were treated to estimate the mutagenicity of both gamma-rays, sodium azide alone and in combination with a view to generate morphological macro-mutations and screen and ascertain the chromosomal aberrations followed by reduction of pollen fertility with increased doses. An attempt was made to know the genetic basis of the chromosomal aberrations. Such aberrations are a source of changes in the pattern of gene regulation at the time of differentiation leading to the formation of cultivars. (author)

  12. The use of azide-alkyne click chemistry in recent syntheses and applications of polytriazole-based nanostructured polymers

    Science.gov (United States)

    Shi, Yi; Cao, Xiaosong; Gao, Haifeng

    2016-02-01

    The rapid development of efficient organic click coupling reactions has significantly facilitated the construction of synthetic polymers with sophisticated branched nanostructures. This Feature Article summarizes the recent progress in the application of efficient copper-catalyzed and copper-free azide-alkyne cycloaddition (CuAAC and CuFAAC) reactions in the syntheses of dendrimers, hyperbranched polymers, star polymers, graft polymers, molecular brushes, and cyclic graft polymers. Literature reports on the interesting properties and functions of these polytriazole-based nanostructured polymers are also discussed to illustrate their potential applications as self-healing polymers, adhesives, polymer catalysts, opto-electronic polymer materials and polymer carriers for drug and imaging molecules.

  13. Research on Synthesis of Trimethylsilane azide%三甲基叠氮硅烷的合成研究

    Institute of Scientific and Technical Information of China (English)

    常淑霞

    2012-01-01

    以三甲基氯硅烷和叠氮化钠为原料,二氯甲烷为溶剂,碘化锌为助催化剂,聚乙二醇400为相转移催化剂,在无水条件下制备三甲基叠氮硅烷。实验考察了滴加时间、保温反应时间、溶剂量、助催化剂量、相转移催化剂量、放大效应等因素对产品收率的影响。反应过程和产品质量通过气相色谱法进行分析、检测。%To' synthesize trimethylsilane azide under the anhydrous condition with trimethylsilane chloride and sodium azide as raw materials, methylene chloride as the resolvent, zinc iodide as catalyst, PTC PEG400 as phase transfer catalyst. To investigate the influencing factors on the yield,such as reaction time,the amount of resolvent,and catalysts (zinc iodide, PCT PEG400), amplification effect, and so on. To detemine the intermediate and final products by gas chromatography.

  14. Development of an improved and early sowing potential variety of jute - binadeshipat-2 using chemical mutagen sodium azide

    International Nuclear Information System (INIS)

    Jute is the important agricultural and industrial resource of Bangladesh for earning foreign currency. Seeds of the widely cultivated variety, CVL-1 were treated with 4 mM to 20mM of sodium azide (NaN3). The treated seeds were grown in M1 to M10 generations. A single plant (selection number C-278) was selected from M2 segregating population on the basis of early sowing potential and late flowering. Ten fiber quality characters were tested and it was found that the fiber quality of the mutant had been improved. Hence, the mutagen sodium azide showed extra potentiality to induce fiber quality characters of jute. The strain C-278 was also tested through Preliminary, Advanced, Zonal Yield Trial and Farmers field trial at different locations of the jute growing area in Bangladesh. The field evaluation team of the National Seed Board (NSB) visited most of the trials and reported that at early sowing and overall performance of the strain C-278 was found best than that of the mother variety. Besides these the strain produced 7.5% and 20% higher fiber yield than the mother variety CVL-1 and a local cultivar, D-154, respectively. After evaluation of the Technical Committee of NSB recommended that the strain C-278 may be released as a variety. The National Seed Board released the strain C-278 as a National jute variety under the name Binadeshipat-2 for cultivation in Bangladesh

  15. Extraction behavior of metal-azide complexes with tri-n-octylamine-benzene . Application to impurities determination in thorium

    International Nuclear Information System (INIS)

    The extraction behavior of the complexes species of azide ions (N3-) with Cd, Cu, Co, Zn, Mn, Fe, Ni, Cr, Pb, Bi, Hg, Ag, Au, Tl, Sn, Pd, Pt, Ru, Eu, Zr, Hf, U and Th with a tertiary long-chain amine (tri-n-octylamine) diluted in benzene was extensively studied. The experiments were performed in nitric and perchloric media. A method for trace analysis of U, Fe, Cu, Zn, Ag, Pd, Pt and Au in grade thorium matrix was proposed . The extraction of uranium and development of methods for the determination of a few micrograms of this element were emphatically studied . Procedures for chemical separation among several elements were outlined in this work . The following experiments were also investigated : the effect of p H on the precipitation of thorium in azide medium ; pre-equilibrium of amine with HNO3; the use of thiourea as complexing agent and the respective cationic species not extractable by the amine; uranium and iron striping with Na2Co3 and HNO3 solutions; the use of EDTA or HCl to strip micrograms of thorium from the organic phase, methods for analysing trace amounts of uranium and thorium by molecular absorption spectrophotometry were developed. The main variables of the extraction procedure such as dilution agent, concentration of the extractant , contact time, and volumetric ratio of the phases were also studied. The analytical control of the experiments was done by atomic and molecular absorption spectrophotometry and gamma-ray spectrometry. (author)

  16. Uncatalyzed thermal gas phase aziridination of alkenes by organic azides. Part I: Mechanisms with discrete nitrene species

    Indian Academy of Sciences (India)

    S PREMILA DEVI; TEJESHWORI SALAM; R H DUNCAN LYNGDOH

    2016-05-01

    Alkene aziridination by azides through uncatalyzed thermal gas phase routes has been studiedusing the DFT B3LYP/6-31G(d,p) method, where the possible role of discrete nitrene intermediates is emphasized.The thermal decomposition of azides is studied using the MP2/aug-cc-pVDZ strategy as well. The MP2(but not the B3LYP) results discount the existence of singlet alkylnitrenes where the alkyl group has an α-hydrogen. Addition of the lowest lying singlet and triplet nitrenes R-N (R = H, Me, Ac) to four different alkenesubstrates leading to aziridine formation was studied by the B3LYP method. Singlet nitrenes with alkenes canyield aziridines via a concerted mechanism, where H-N insertion takes place without a barrier, whereas Me-Nshows larger barriers than Ac-N. Methyl substitution in the alkene favors this reaction. Triplet nitrene additionto alkenes is studied as a two-step process, where the initially formed diradical intermediates cyclize to formaziridines by ISC (intersystem crossing) and collapse. Scope for C-C bond rotation in the diradical leads to lossof stereochemical integrity for triplet nitrene addition to cis- and trans-2-butenes. Geometries of the transitionstates in the various reaction steps studied here are described as “early” or “late” in good accordance with theHammond postulate.

  17. Design and Synthesis of New Chacones Substituted with Azide/Triazole Groups and Analysis of Their Cytotoxicity Towards HeLa Cells

    Directory of Open Access Journals (Sweden)

    José A. F. P. Villar

    2012-08-01

    Full Text Available A series of new chalcones substituted with azide/triazole groups were designed and synthesized, and their cytotoxic activity was evaluated in vitro against the HeLa cell line. O-Alkylation, Claisen-Schmidt condensation and Cu(I-catalyzed cycloaddition of azides with terminal alkynes were applied in key steps. Fifteen compounds were tested against HeLa cells. Compound 8c was the most active molecule, with an IC50 value of 13.03 µM, similar to the value of cisplatin (7.37 µM.

  18. Comparative analysis of Cu (I)-catalyzed alkyne-azide cycloaddition (CuAAC) and strain-promoted alkyne-azide cycloaddition (SPAAC) in O-GlcNAc proteomics.

    Science.gov (United States)

    Li, Shanshan; Zhu, He; Wang, Jiajia; Wang, Xiaomin; Li, Xu; Ma, Cheng; Wen, Liuqing; Yu, Bingchen; Wang, Yuehua; Li, Jing; Wang, Peng George

    2016-06-01

    O-linked β-N-acetylglucosamine (O-GlcNAc) is emerging as an essential protein post-translational modification in a range of organisms. It is involved in various cellular processes such as nutrient sensing, protein degradation, gene expression, and is associated with many human diseases. Despite its importance, identifying O-GlcNAcylated proteins is a major challenge in proteomics. Here, using peracetylated N-azidoacetylglucosamine (Ac4 GlcNAz) as a bioorthogonal chemical handle, we described a gel-based mass spectrometry method for the identification of proteins with O-GlcNAc modification in A549 cells. In addition, we made a labeling efficiency comparison between two modes of azide-alkyne bioorthogonal reactions in click chemistry: copper-catalyzed azide-alkyne cycloaddition (CuAAC) with Biotin-Diazo-Alkyne and stain-promoted azide-alkyne cycloaddition (SPAAC) with Biotin-DIBO-Alkyne. After conjugation with click chemistry in vitro and enrichment via streptavidin resin, proteins with O-GlcNAc modification were separated by SDS-PAGE and identified with mass spectrometry. Proteomics data analysis revealed that 229 putative O-GlcNAc modified proteins were identified with Biotin-Diazo-Alkyne conjugated sample and 188 proteins with Biotin-DIBO-Alkyne conjugated sample, among which 114 proteins were overlapping. Interestingly, 74 proteins identified from Biotin-Diazo-Alkyne conjugates and 46 verified proteins from Biotin-DIBO-Alkyne conjugates could be found in the O-GlcNAc modified proteins database dbOGAP (http://cbsb.lombardi.georgetown.edu/hulab/OGAP.html). These results suggested that CuAAC with Biotin-Diazo-Alkyne represented a more powerful method in proteomics with higher protein identification and better accuracy compared to SPAAC. The proteomics credibility was also confirmed by the molecular function and cell component gene ontology (GO). Together, the method we reported here combining metabolic labeling, click chemistry, affinity-based enrichment, SDS

  19. Techniques in gas-phase thermolyses - Part 7. Direct surface participation in gas-phase Curie-point pyrolysis: The pyrolysis of phenyl azide

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars

    1986-01-01

    The possible direct participation of the hot reactor surface in the formation of pyrolysis products was elucidated through the pyrolytic decomposition of phenyl azide. It is demonstrated that the intermediate phenyl nitrene generated reacts with elemental carbon at the filament surface, leading...

  20. A new method of nitrogenation of RE-TM alloys via chemical reaction with sodium azide as an oxygen-free nitrogen source

    International Nuclear Information System (INIS)

    Y2Fe17 and other RE-Fe-based compounds have been successfully nitrogenated by heating mixtures of powdered alloy with sodium azide at temperatures between 300 and 450 C. The high nitrogenation power of NaN3 seems to come from its low decomposition temperature and an improved nitrogen diffusion rate through the particle surfaces cleaned by sodium. (orig.)

  1. Covalent attachment of diphosphine ligands to glassy carbon electrodes via Cu-catalyzed alkyne-azide cycloaddition. Metallation with Ni(II).

    Science.gov (United States)

    Das, Atanu K; Engelhard, Mark H; Lense, Sheri; Roberts, John A S; Bullock, R Morris

    2015-07-21

    Covalent tethering of P(Ph)2N(C6H4C≡CH)2 ligands (P(Ph)2N(C6H4C≡CH)2 = 1,5-di-(4-ethynylphenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane) to planar, azide-terminated glassy carbon electrode surfaces has been accomplished using a Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) coupling reaction, using a BH3←P protection-deprotection strategy. Deprotected, surface-confined ligands were metallated using [Ni(II)(MeCN)6](BF4)2. X-ray photoelectron spectroscopic measurements demonstrate that metallation introduced 1.3 equivalents Ni(II) per diphosphine onto the electrode surface. Exposure of the surface to a second diphosphine ligand, P(Ph)2N(Ph)2, resulted in the removal of Ni from the surface. Protection, coupling, deprotection, and metallation conditions were optimized using solution-phase model systems, with benzyl azide as a model for the azide-terminated carbon surface; these reactions generate a [Ni(II)(diphosphine)2](2+) complex. PMID:25811536

  2. 1,5-Iodonaphthyl azide-inactivated V3526 protects against aerosol challenge with virulent venezuelan equine encephalitis virus.

    Science.gov (United States)

    Gupta, Paridhi; Sharma, Anuj; Spurgers, Kevin B; Bakken, Russell R; Eccleston, Lori T; Cohen, Jeffrey W; Honnold, Shelley P; Glass, Pamela J; Maheshwari, Radha K

    2016-05-27

    Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus. VEEV is highly infectious in aerosolized form and has been identified as a bio-terrorism agent. There is no licensed vaccine for prophylaxis against VEEV. The current IND vaccine is poorly immunogenic and does not protect against an aerosol challenge with virulent VEEV. We have previously shown that VEEV inactivated by 1,5-iodonaphthyl azide (INA) protects against footpad challenge with virulent VEEV. In this study, we inactivated an attenuated strain of VEEV, V3526, with INA and evaluated its protective efficacy against aerosol challenge with wild type VEEV. We demonstrated that among three routes of immunization, intramuscular immunization with INA-inactivate V3526 (INA-iV3526) provided complete protection against aerosol challenge with virulent VEEV. Our data suggests that INA-iV3526 can be explored further for development as an effective vaccine candidate against aerosol challenge of virulent VEEV. PMID:27129427

  3. Density Functional Study on [3+2]-Dipolar Cycloaddition Reaction of the N-heterocyclic Carbene Boryl Azide with Olefins

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinghui; Wang, Ketai; Niu, Teng; Li, Shanshan [Lanzhou Univ. of Arts and Science, Lanzhou (Korea, Republic of)

    2014-05-15

    The cycloaddition reactions of the N-heterocyclic carbene boryl azide with methyl acrylate, butenone, and hexafluoropropene have been investigated theoretically. Solvent effects on these reactions have been explored by calculation that included a polarizable continuum model (PCM) for the solvent (C6H6). The title reaction could produce 4- and 5-substituted 1,2,3-triazolines, respectively. The reaction systems have the higher chemical reactivity with the low barriers and could be favored. Yet the smaller differences have been found to occur in energetics, and the cycloaddition reactions occur for s-trans conformations over s-cis conformations. The calculations indicated that the cycloaddition reaction of the alkenes have certain regioselectivity.

  4. Density Functional Study on [3+2]-Dipolar Cycloaddition Reaction of the N-heterocyclic Carbene Boryl Azide with Olefins

    International Nuclear Information System (INIS)

    The cycloaddition reactions of the N-heterocyclic carbene boryl azide with methyl acrylate, butenone, and hexafluoropropene have been investigated theoretically. Solvent effects on these reactions have been explored by calculation that included a polarizable continuum model (PCM) for the solvent (C6H6). The title reaction could produce 4- and 5-substituted 1,2,3-triazolines, respectively. The reaction systems have the higher chemical reactivity with the low barriers and could be favored. Yet the smaller differences have been found to occur in energetics, and the cycloaddition reactions occur for s-trans conformations over s-cis conformations. The calculations indicated that the cycloaddition reaction of the alkenes have certain regioselectivity

  5. Synthesis of structurally defined scaffolds for bivalent ligand display based on glucuronic acid anilides. The degree of tertiary amide isomerism and folding depends on the configuration of a glycosyl azide.

    Science.gov (United States)

    Tosin, Manuela; Murphy, Paul V

    2005-05-13

    [structures: see text] Syntheses and structural analyses of bivalent carbohydrates based on anilides of glucuronic acid are described. Secondary anilides predominantly adopted the Z-anti structure; there is also evidence for population of the Z-syn isomer. Bivalent tertiary anilides displayed two signal sets in their NMR spectra, consistent with the presence of (i) a major isomer where both amides have E configurations (EE) and (ii) a minor isomer where one amide is E and the other Z (EZ). Qualitative NOE/ROE spectroscopic studies in solution support the proposal that the anti conformation is preferred for E amides. The crystal structure of one bivalent tertiary anilide showed E-anti and E-syn structural isomers; intramolecular carbohydrate-carbohydrate stacking was observed and mediated by carbonyl-pyranose, azide-azide, and pyranose-aromatic interactions. The EE to EZ isomer ratio, or the degree of folding, for tertiary amides, was greatest for a bivalent compound containing two alpha-glycosyl azide groups; this was enhanced in water, suggesting that hydrophobic interactions are partially but not wholly responsible. Computational methods predicted azide-aromatic (N...H-C interaction) and azide-azide interactions for folded isomers. The close contact of the azide and aromatic protons (N...H-C interaction) was observed upon examination of the close packing in the crystal structure of a related monomer. It is proposed that the alpha-azide group is more optimally aligned, compared to the beta-azide, to facilitate interaction and minimize the surface area of the hydrophobic groups exposed to water, and this leads to the increased folding. The alkylation of bivalent secondary anilides induces a switch from Z to E amide that alters the scaffold orientation. The synthesis of a bivalent mannoside, based on a secondary anilide scaffold, for investigation of mannose-binding receptor cross-linking and lattice formation is described. PMID:15876103

  6. A Direct Access to 7-Aminoindoles via Iridium-Catalyzed Mild C-H Amidation of N-Pivaloylindoles with Organic Azides.

    Science.gov (United States)

    Kim, Youyoung; Park, Juhyeon; Chang, Sukbok

    2016-04-15

    Ir(III)-catalyzed regioselective direct C-7 amidation of indoles in reaction with organic azides has been developed. While its efficiency was varied by the choice of N-directing groups, N-pivaloylindoles were most effective in undergoing the desired amidation at room temperature over a broad range of substrates. The reaction was scalable, and deprotection of the chelation group was also facile. PMID:27023669

  7. CuO-promoted construction of N-2-aryl-substituted-1,2,3-triazoles via azide-chalcone oxidative cycloaddition and post-triazole arylation.

    Science.gov (United States)

    Zhang, Yuanqing; Li, Xiaolong; Li, Jihui; Chen, Jinying; Meng, Xu; Zhao, Mingming; Chen, Baohua

    2012-01-01

    An efficient one-pot three-component stepwise approach for the synthesis of N-2-aryl-substituted-1,2,3-triazoles has been developed. By using this azide-chalcone oxidative cycloaddition and post-triazole arylation, a series of N-2-aryl-substituted-1,2,3-triazoles are readily prepared under mild conditions in excellent yields and high regioselectivity. Both the catalyst and substrates are readily available. PMID:22133007

  8. Traceless Azido Linker for the Solid-Phase Synthesis of NH-1,2,3-Triazoles via Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2010-01-01

    A broadly useful acid-labile traceless azido linker for the solid-phase synthesis of NH-1,2,3-triazoles is presented. A variety of alkynes were efficiently immobilized on a range of polymeric supports by Cu(I)-mediated azide-alkyne cycloadditions. Supported triazoles showed excellent compatibilit...... with subsequent peptide chemistry. Release of pure material (typically >95%) from the solid support was readily achieved by treatment with aqueous TFA....

  9. γ-Fe2O3:A magnetic separable catalyst for synthesis of 5-substituted 1H-tetrazoles from nitriles and sodium azide

    Institute of Scientific and Technical Information of China (English)

    Gang Qi; Yong Dai

    2010-01-01

    An efficient route for the synthesis of 5-substituted 1H-tetrazole via[2+3]cycloaddition of nitriles and sodium azide is reported using γ-Fe2O3 nanoparticles as a magnetic separable catalyst.Under optimized conditions,the moderate to good yields(71-95%)can be obtained.The catalyst can be easily separated by a magnet and reused for several circles.

  10. Facile synthesis of linear-dendritic cholesteryl-poly(epsilon-caprolactone)-b-(L-lysine)(G2) by thiol-ene and azide-alkyne "click" reactions

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Binder, W.H.; Tanner, S.;

    2010-01-01

    The construction of a linear-dendritic block copolymer consisting of terminal cholesteryl moiety, poly(epsilon-caprolactone), and a second generation L-lysine dendron has been accomplished by the combination of copper(I) catalyzed azide-alkyne and UV-triggered thiol-ene "click" reactions. Ring-op...... thiocholesterol. Near to quantitative functionalization of the intermediate and final products has been attained as confirmed by NMR spectroscopy and MALDI-TOF spectrometry....

  11. Copper-mediated C(sp(3))-H azidation with Me3SiN3: synthesis of imidazoles from ketones and aldehydes.

    Science.gov (United States)

    Xie, Zeqiang; Deng, Jiaojiao; Qiu, Zhiping; Li, Juan; Zhu, Qiang

    2016-05-11

    The efficient construction of 2,4,5-trisubstituted imidazoles, through a copper-mediated three-component reaction involving ketones, aldehydes, and Me3SiN3, has been developed. During the process, 4 C-N bonds were formed sequentially. Experimental results and DFT calculations suggested that azidation of the alpha methylene group of the ketone was the key C-N bond-forming step. PMID:27101465

  12. Formation of 1,4- and 1,5-regioisomers of triazolines in reactions of 2-ethoxyethyl azide with monosubstituted ethylenes

    International Nuclear Information System (INIS)

    The structural specificity of the reactions of 2-ethoxyethyl azide with alkenes RCH=CH2 [R = CH2C6H5, CH2OC6H13, CH(OC2H5)2, C6H5] was studied. The formation of 1,4- and 1,5-substituted triazolines and the high stabilities of the latter were demonstrated by PMR spectroscopy, data from gas-liquid chromatography (GLC), and the kinetics of thermolysis

  13. Steering the azido-tetrazole equilibrium of 4-azidopyrimidines via substituent variation - implications for drug design and azide-alkyne cycloadditions.

    Science.gov (United States)

    Thomann, A; Zapp, J; Hutter, M; Empting, M; Hartmann, R W

    2015-11-21

    This paper focuses on an interesting constitutional isomerism called azido-tetrazole equilibrium which is observed in azido-substituted N-heterocycles. We present a systematic investigation of substituent effects on the isomer ratio within a 2-substituted 4-azidopyrimidine model scaffold. NMR- and IR-spectroscopy as well as X-ray crystallography were employed for thorough analysis and characterization of synthesized derivatives. On the basis of this data, we demonstrate the possibility to steer this valence tautomerism towards the isomer of choice by means of substituent variation. We show that the tetrazole form can act as an efficient disguise for the corresponding azido group masking its well known reactivity in azide-alkyne cycloadditions (ACCs). In copper(I)-catalyzed AAC reactions, substituent-stabilized tetrazoles displayed a highly decreased or even abolished reactivity whereas azides and compounds in the equilibrium were directly converted. By use of an acid sensitive derivative, we provide, to our knowledge, the first experimental basis for a possible exploitation of this dynamic isomerism as a pH-dependent azide-protecting motif for selective SPAAC conjugations in aqueous media. Finally, we demonstrate the applicability and efficiency of stabilized tetrazolo[1,5-c]pyrimidines for Fragment-Based Drug Design (FBDD) in the field of quorum sensing inhibitors. PMID:26340222

  14. Genetically Encoded Azide Containing Amino Acid in Mammalian Cells Enables Site-Specific Antibody-Drug Conjugates Using Click Cycloaddition Chemistry.

    Science.gov (United States)

    VanBrunt, Michael P; Shanebeck, Kurt; Caldwell, Zachary; Johnson, Jeffrey; Thompson, Pamela; Martin, Thomas; Dong, Huifang; Li, Gary; Xu, Hengyu; D'Hooge, Francois; Masterson, Luke; Bariola, Pauline; Tiberghien, Arnaud; Ezeadi, Ebele; Williams, David G; Hartley, John A; Howard, Philip W; Grabstein, Kenneth H; Bowen, Michael A; Marelli, Marcello

    2015-11-18

    Antibody-drug conjugates (ADC) have emerged as potent antitumor drugs that provide increased efficacy, specificity, and tolerability over chemotherapy for the treatment of cancer. ADCs generated by targeting cysteines and lysines on the antibody have shown efficacy, but these products are heterogeneous, and instability may limit their dosing. Here, a novel technology is described that enables site-specific conjugation of toxins to antibodies using chemistry to produce homogeneous, potent, and highly stable conjugates. We have developed a cell-based mammalian expression system capable of site-specific integration of a non-natural amino acid containing an azide moiety. The azide group enables click cycloaddition chemistry that generates a stable heterocyclic triazole linkage. Antibodies to Her2/neu were expressed to contain N6-((2-azidoethoxy)carbonyl)-l-lysine at four different positions. Each site allowed over 95% conjugation efficacy with the toxins auristatin F or a pyrrolobenzodiazepine (PBD) dimer to generate ADCs with a drug to antibody ratio of >1.9. The ADCs were potent and specific in in vitro cytotoxicity assays. An anti Her2/neu conjugate demonstrated stability in vivo and a PBD containing ADC showed potent efficacy in a mouse tumor xenograph model. This technology was extended to generate fully functional ADCs with four toxins per antibody. The high stability of the azide-alkyne linkage, combined with the site-specific nature of the expression system, provides a means for the generation of ADCs with optimized pharmacokinetic, biological, and biophysical properties. PMID:26332743

  15. Improved synthesis of [18F]FLETT via a fully automated vacuum distillation method for [18F]2-fluoroethyl azide purification

    International Nuclear Information System (INIS)

    The synthesis of [18F]2-fluoroethyl azide and its subsequent click reaction with 5-ethynyl-2′-deoxyuridine (EDU) to form [18F]FLETT was performed using an iPhase FlexLab module. The implementation of a vacuum distillation method afforded [18F]2-fluoroethyl azide in 87±5.3% radiochemical yield. The use of Cu(CH3CN)4PF6 and TBTA as catalyst enabled us to fully automate the [18F]FLETT synthesis without the need for the operator to enter the radiation field. [18F]FLETT was produced in higher overall yield (41.3±6.5%) and shorter synthesis time (67 min) than with our previously reported manual method (32.5±2.5% in 130 min). - Highlights: • An automated vacuum distillation method for the purification of [18F]2-fluoroethyl azide. • Significantly shortened synthesis protocol. • Increased yield and higher specific activity

  16. Well-defined polyethylene-based graft terpolymers by combining nitroxide-mediated radical polymerization, polyhomologation and azide/alkyne “click” chemistry†

    KAUST Repository

    Alkayal, Nazeeha

    2016-03-30

    Novel well–defined polyethylene–based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” chemistry. Three steps were involved in this approach: (i) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using the PE-OH as macroinitiator, (ii) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (iii) “click” linking reaction to afford the PE-based graft terpolymers. All intermediates and final products were characterized by high-temperature size exclusion chromatography (HT-SEC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC).

  17. Structural Stability and Vibrational Analyses of Haloselenonyl Azides, XSeO2-NNN, where X is F, Cl, Br

    Directory of Open Access Journals (Sweden)

    Wolfgang Förِner

    2005-10-01

    Full Text Available The structural stability of haloselenonyl azides was investigated by quantum mechanical Møller-Plesset perturbation theory of second order and density functional theory calculations. The 6-311+G** basis set was used to include polarization and diffuse functions in the calculations at the DFT-B3LYP level. The potential scans for the rotation of the -NNN rotor were calculated and found to be consistent with a single minimum that corresponds to a gauche conformation (-NNN moiety nearly eclipses one of the two selenonyl Se=O bonds for the three halogens at ambient temperature. The structural parameters for the minima calculated by MP2 and DFT turned out to be very similar. The vibrational modes, infrared and Raman intensities as well as depolarization ratios were calculated at DFT-B3LYP/6-311+G** level for the three molecules in their gauche conformations. The potential energy distributions among symmetry coordinates of the normal modes of the molecules in their gauche conformation were then computed from normal coordinate analyses.

  18. The Electrode as Organolithium Reagent: Catalyst-Free Covalent Attachment of Electrochemically Active Species to an Azide-Terminated Glassy Carbon Electrode Surface

    Energy Technology Data Exchange (ETDEWEB)

    Das, Atanu K.; Engelhard, Mark H.; Liu, Fei; Bullock, R. Morris; Roberts, John A.

    2013-12-02

    Glassy carbon electrodes have been activated for modification with azide groups and subsequent coupling with ferrocenyl reagents by a catalyst-free route using lithium acetylide-ethylenediamine complex, and also by the more common Cu(I)-catalyzed alkyne-azide coupling (CuAAC) route, both affording high surface coverages. Electrodes were preconditioned at ambient temperature under nitrogen, and ferrocenyl surface coverages obtained by CuAAC were comparable to those reported with preconditioning at 1000 °C under hydrogen/nitrogen. The reaction of lithium acetylide-ethylenediamine with the azide-terminated electrode affords a 1,2,3-triazolyllithium-terminated surface that is active toward covalent C-C coupling reactions including displacement at an aliphatic halide and nucleophilic addition at an aldehyde. For example, surface ferrocenyl groups were introduced by reaction with (6-iodohexyl)ferrocene; the voltammetry shows narrow, symmetric peaks indicating uniform attachment. Coverages are competitive with those obtained by the CuAAC route. X-ray photoelectron spectroscopic data, presented for each synthetic step, are consistent with the proposed reactions. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy. A portion of the research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

  19. Site-specific bioconjugation of a murine dihydrofolate reductase enzyme by copper(I-catalyzed azide-alkyne cycloaddition with retained activity.

    Directory of Open Access Journals (Sweden)

    Sung In Lim

    Full Text Available Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC is an efficient reaction linking an azido and an alkynyl group in the presence of copper catalyst. Incorporation of a non-natural amino acid (NAA containing either an azido or an alkynyl group into a protein allows site-specific bioconjugation in mild conditions via CuAAC. Despite its great potential, bioconjugation of an enzyme has been hampered by several issues including low yield, poor solubility of a ligand, and protein structural/functional perturbation by CuAAC components. In the present study, we incorporated an alkyne-bearing NAA into an enzyme, murine dihydrofolate reductase (mDHFR, in high cell density cultivation of Escherichia coli, and performed CuAAC conjugation with fluorescent azide dyes to evaluate enzyme compatibility of various CuAAC conditions comprising combination of commercially available Cu(I-chelating ligands and reductants. The condensed culture improves the protein yield 19-fold based on the same amount of non-natural amino acid, and the enzyme incubation under the optimized reaction condition did not lead to any activity loss but allowed a fast and high-yield bioconjugation. Using the established conditions, a biotin-azide spacer was efficiently conjugated to mDHFR with retained activity leading to the site-specific immobilization of the biotin-conjugated mDHFR on a streptavidin-coated plate. These results demonstrate that the combination of reactive non-natural amino acid incorporation and the optimized CuAAC can be used to bioconjugate enzymes with retained enzymatic activity.

  20. Conventional and microwave-assisted multicomponent reaction of alkyne, halide and sodium azide catalyzed by copper apatite as heterogeneous base and catalyst in water

    Directory of Open Access Journals (Sweden)

    Sandip Kale

    2012-04-01

    Full Text Available The conventional and microwave assisted multicomponent synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide using copper apatite catalyst in water is reported. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the copper hydroxyapatite. The catalyst could be used ten times without further treatment and activation under controlled microwave heating. The protocol was also applicable for various alkynes and halides which affords desired product in good to excellent yield.

  1. Assessment of the Full Compatibility of Copper(I)-Catalyzed Alkyne-Azide Cycloaddition and Oxime Click Reactions for bis-Labelling of Oligonucleotides

    OpenAIRE

    Estalayo-Adriàn, Sandra; Lartia, Rémy; Meyer, Albert; Vasseur, Jean-Jacques; Morvan, François; Defrancq, Eric

    2014-01-01

    The conjugation of oligonucleotides with reporters is of great interest for improving their intrinsic properties or endowing new ones. In this context, we report herein a new procedure for the bis-labelling of oligonucleotides through oxime ligation (Click-O) and copper(I)-catalyzed alkyne–azide cycloaddition (Click-H). 5′-Azido and 3′-aldehyde precursors were incorporated into oligonucleotides, and subsequent coupling reactions through Click-O and Click-H (or vice versa) were successfully ac...

  2. Synthesis and post-synthetic modification of amine-, alkyne-, azide- and nitro-functionalized metal-organic frameworks based on DUT-5.

    Science.gov (United States)

    Gotthardt, Meike A; Grosjean, Sylvain; Brunner, Tobias S; Kotzel, Johannes; Gänzler, Andreas M; Wolf, Silke; Bräse, Stefan; Kleist, Wolfgang

    2015-10-14

    Functionalized 4,4'-biphenyldicarboxylic acid molecules with additional amine, alkyne, azide or nitro groups were prepared and applied in the synthesis of novel metal-organic frameworks and mixed-linker metal-organic frameworks isoreticular to DUT-5. The properties of the frameworks could be tuned by varying the number of functional groups in the materials and the amine groups were employed in post-synthetic modification reactions without changing the framework structure or significantly decreasing the porosity of the materials. PMID:26336838

  3. Formation of 1,4- and 1,5-regioisomers of triazolines in reactions of 2-ethoxyethyl azide with monosubstituted ethylenes

    Energy Technology Data Exchange (ETDEWEB)

    Lanovaya, G.A.; Mishchenko, V.F.; Korniets, E.D.

    1987-12-01

    The structural specificity of the reactions of 2-ethoxyethyl azide with alkenes RCH=CH/sub 2/ (R = CH/sub 2/C/sub 6/H/sub 5/, CH/sub 2/OC/sub 6/H/sub 13/, CH(OC/sub 2/H/sub 5/)/sub 2/, C/sub 6/H/sub 5/) was studied. The formation of 1,4- and 1,5-substituted triazolines and the high stabilities of the latter were demonstrated by PMR spectroscopy, data from gas-liquid chromatography (GLC), and the kinetics of thermolysis.

  4. Application of Azide-Alkyne Cycloaddition “Click Chemistry” for the Synthesis of Grb2 SH2 Domain-Binding Macrocycles

    OpenAIRE

    Choi, Won Jun; Shi, Zhen-Dan; Worthy, Karen M.; Bindu, Lakshman; Karki, Rajeshri G.; Nicklaus, Marc C.; Fisher, Robert J.; Burke, Terrence R

    2006-01-01

    Copper (I) promoted [3+2] Huisgen cycloaddition of azides with terminal alkynes was used to prepare triazole-containing macrocycles based on the Grb2 SH2 domain-binding motif, “Pmp-Ac6 c-Asn”, where Pmp and Ac6 c stand for 4-phosphonomethylphenylalanine and 1-aminocyclohexanecarboxylic acid, respectively. When cycloaddition reactions were conducted at 1 mM substrate concentrations cyclization of monomeric units occurred. At 2 mM substrate concentrations the predominant products were macrocycl...

  5. Gamma irradiation and sodium azide induced changes in growth, leaf protein patterns and genomic DNA of two strains of maize under drought stress

    International Nuclear Information System (INIS)

    Growth potentials of two pure strains (G4 and Rg11) of maize (Zea mays L.) were evaluated under normal irrigation and drought stress. It could be generally concluded that Rg 11 was more fitting under normal irrigation, whereby G4 strain coped better with drought stress. Grain treatment with gamma irradiation (60 Gy) or sodium azide (0.001 M) induced significantly enhanced growth in case of strain G4, under normal irrigation or drought condition, with a higher performance by gamma rays. Treatment with sodium azide gave better results with Rg11 plants. These changes were accompanied with a marked modulation in the protein patterns of leaves of both strains. The most interesting results were the induction of a least six new protein bands in strain G4 under drought stress and three in the Rg11 plants, as compared with those in corresponding control plants subjected to normal irrigation. Meanwhile, similar three proteins (MR: 74, 53, 41 KDa) were repressed in each strain in response to drought

  6. Poli (metil azoteto de glicidila - GAP. I: síntese e caracterização Glycidyl azide polymer (GAP. I: syntheses and characterization

    Directory of Open Access Journals (Sweden)

    Sandro P. Ribeiro

    2012-01-01

    Full Text Available O poli (metil azoteto de glicidila - GAP - é um material energético que pode ser utilizado como aglutinante (binder e como plastificante energético em compostos explosivos e propulsores de foguetes. Neste trabalho, foi abordada a síntese do (GAP através da conversão direta da epicloridrina (ECH a GAP. Os reagentes utilizados foram azida de sódio, epicloridrina e vários álcoois extensores de cadeias, o etanodiol, o 1,4-butanodiol, o dietilenoglicol e o glicerol. Alguns parâmetros de operação foram avaliados, como o tempo de reação, a proporção entre os reagentes, dois tipos de solvente e a ordem de adição dos reagentes. A variável observada para a análise foi a massa molecular do GAP. Todos os materiais sintetizados também foram caracterizados por análises de FTIR, UV, RMN, DSC, análise elementar e TGA. Uma maior massa molecular, maior rendimento e uma melhor conversão do grupo azida a GAP foram obtidos com a adição de epicloridrina sobre a azida de sódio e usando DMF como solvente.GAP is an aliphatic polyether that includes hydroxyl groups and highly energetic azide groups. Thus, it is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP was synthesized and characterized by direct conversion of epichlorohydrin. GAP was synthesized by reaction of sodium azide, epichlorohydrin, and some extensor alcohols. The investigation focused on the effects of some key reaction parameters including reagent proportions, reaction time and two different solvents. The product was characterized by FTIR, UV, NMR, DSC, elemental analysis, TGA and GPC. The species were also evaluated through molecular weight (GPC, glass transition temperature (DSC, ignition time and sensitivity.

  7. Click synthesis of 1,4-disubstituted-1,2,3-triazoles catalysed by CuO-CeO2 nanocomposite in the presence of amberlite-supported azide

    Indian Academy of Sciences (India)

    Jalal Albadi; Jafar Abbasi Shiran; Azam Mansournezhad

    2014-01-01

    A CuO-CeO2 nanocomposite in the presence of amberlite-supported azide has been used for the click synthesis of 1,4-disubstituted-1,2,3-triazoles in good yields. This catalyst can be reused several times without any significant decrease in the catalytic activity.

  8. The effects of duration of pre-soaking treatments on the frequency and spectrum of mutations induced by sodium azide in CES 14 Mungbean variety

    International Nuclear Information System (INIS)

    Seeds of mungbean variety CES 14 were treated with 10-3 sodium azide for 2 hours buffered at pH 3 after various pre-soaking treatment durations of 0, 4, 6, 8, 10, 12, 14 and 16 hours. The biological parameters that were significantly affected by the treatments in the M1 were germination, seedling height and survival. The chlorophyll and other morphological mutations in the M2 gradually increased with increasing pre-soaking time. The treatment that had the lowest mutation rate was the 16-hour pre-soaked seeds. No chlorophyll mutation was noted in both the water and buffer control. One variant was noted, however, in the buffer control. (author)

  9. Functionalization of Multi-Walled Carbon Nanotubes with Thermo-Responsive Azide-Terminated Poly(N-isopropylacrylamide via Click Reactions

    Directory of Open Access Journals (Sweden)

    Yujun Feng

    2013-04-01

    Full Text Available Covalently functionalized multi-walled carbon nanotubes (MWNTs were prepared by grafting well-defined thermo-responsive poly(N-isopropylacrylamide (PNIPAM via click reactions. First, azide-terminated poly(N-isopropylacrylamide (N3-PNIPAM was synthesized by reversible addition fragmentation chain-transfer (RAFT polymerization, and then the N3-PNIPAM moiety was connected onto MWNTs by click chemistry. The products were characterized by means of FT-IR, TGA and TEM. The results show that the modification of MWNTs is very successful and MWNTs functionalized by N3-PNIPAM (MWNTs-PNIPAM have good solubility and stability in water. TEM images show the functionalized MWNTs are dispersed individually, indicating that the bundles of original MWNTs are separated into individual tubes by surface modification with polymer chains. These MWNTs modified with PNIPAM represent a potential nano-material for preparation of hydrophilic composite materials.

  10. Cu-MCM-41 nanoparticles: An efficient catalyst for the synthesis of 5-substituted 1-tetrazoles via [3+2] cycloaddition reaction of nitriles and sodium azide

    Indian Academy of Sciences (India)

    Mohammad Abdollahi-Alibeik; Ali Moaddeli

    2016-01-01

    [3+2] cycloaddition reaction of various types of nitriles and sodium azide (NaN3) were studied in the presence of nano-sized Cu-MCM-41 as an efficient recoverable heterogeneous catalyst. Nano-sized Cu-MCM-41 mesoporous molecular sieves with various Si/Cu molar ratios were synthesized by direct insertion of metal ions at room temperature. The textural properties of the materials have been studied by means of XRD, FTIR, SEM and TEM techniques. Catalytic behavior of Cu-MCM-41 was also investigated by pyridine absorption and potentiometric titration. The reactions data verified characterization results and show that Cu-MCM-41 with Si/Cu molar ratio of 20 has considerably better catalytic activity compared to the other molar ratios. To investigate reusability, the catalyst was recovered by simple filtration and reused for several cycles with consistent activity.

  11. Effects of UVA irradiation, aryl azides, and reactive oxygen species on the orthogonal inactivation of the human immunodeficiency virus (HIV-1)

    International Nuclear Information System (INIS)

    Previously we reported that hydrophobic aryl azides partition into hydrophobic regions of the viral membrane of enveloped viruses and inactivate the virus upon UVA irradiation for 2 min. Prolonged irradiation (15 min) resulted in viral protein aggregation as visualized via Western blot analysis, due to reactive oxygen species (ROS) formation, with preservation of the surface antigenic epitopes. Herein, we demonstrate that these aggregates show detergent resistance and that this property may be useful towards the creation of a novel orthogonal virus inactivation strategy for use in preparing experimental vaccines. When ROS-modified HIV virus preparations were treated with 1% Triton X-100, there was an increase in the percent of viral proteins (gp41, p24) in the viral pellet after ultracentrifugation through sucrose. Transmission electron microscopy (TEM) of these detergent-resistant pellets shows some recognizable virus fragments, and immunoprecipitation studies of the gp41 aggregates suggest the aggregation is covalent in nature, involving short-range interactions.

  12. Allium cepa anaphase-telophase root tip chromosome aberration assay on N-methyl-N-nitrosourea, maleic hydrazide, sodium azide, and ethyl methanesulfonate.

    Science.gov (United States)

    Rank, J; Nielsen, M H

    1997-04-24

    The Allium anaphase-telophase assay was used to show genotoxicity of N-methyl-N-nitrosourea (MNU), maleic hydrazide (MH), sodium azide (NaN3) and ethyl methanesulfonate (EMS). All agents induced chromosome aberrations at statistically significant levels. The rank of the lowest doses with positive effect was as follows: NaN3 0.3 mg/l Allium test for NaN3 and EMS were in a lower range than that found for the other plant assays. EMS and MMS (methyl methanesulfonate), two chemicals used as positive controls in mutagenicity testing, were compared in the Allium test, and MMS was found to be about ten times more potent in inducing chromosome aberrations than EMS. Recording of micronuclei in interphase cells showed that this endpoint does not give more information of clastogenicity than recording of chromosome aberrations in anaphase-telophase cells. PMID:9150760

  13. Synthesis of chiral N-phosphoryl aziridines through enantioselective aziridination of alkenes with phosphoryl azide via Co(II-based metalloradical catalysis

    Directory of Open Access Journals (Sweden)

    Jingran Tao

    2014-06-01

    Full Text Available The Co(II complex of a new D2-symmetric chiral porphyrin 3,5-DiMes-QingPhyrin, [Co(P6], can catalyze asymmetric aziridination of alkenes with bis(2,2,2-trichloroethylphosphoryl azide (TcepN3 as a nitrene source. This new Co(II-based metalloradical aziridination is suitable for different aromatic olefins, producing the corresponding N-phosphorylaziridines in good to excellent yields (up to 99% with moderate to high enantioselectivities (up to 85% ee. In addition to mild reaction conditions and generation of N2 as the only byproduct, this new metalloradical catalytic system is highlighted with a practical protocol that operates under neutral and non-oxidative conditions.

  14. 'Clicking' on the nanoscale: 1,3-dipolar cycloaddition of terminal acetylenes on azide functionalized, nanometric surface templates with nanometer resolution

    Science.gov (United States)

    Haensch, Claudia; Hoeppener, Stephanie; Schubert, Ulrich S.

    2009-04-01

    Electro-oxidative lithography is used as a tool to create chemical nanostructures on an n-octadecyltrichlorosilane (OTS) monolayer self-assembled on silicon. The use of a bromine precursor molecule, which is exclusively assembled on these chemical templates, can be used to further functionalize the nanostructures by the site-selective generation of azide functions and performing the highly effective 1,3-dipolar cycloaddition reaction with acetylene functionalized molecules. The versatility of this reaction scheme provides the potential to integrate a large variety of functional molecules, to tailor the surface properties of the nanostructures or to anchor molecular building blocks or particles in confined, pre-defined surface areas. The results demonstrated in the present study introduce a conceivable route towards the functionalization of chemically active surface templates with high fidelity and reliability. It is demonstrated that surface features with a lateral resolution of 50 nm functionalized with propargyl alcohol can be fabricated.

  15. 'Clicking' on the nanoscale: 1,3-dipolar cycloaddition of terminal acetylenes on azide functionalized, nanometric surface templates with nanometer resolution

    International Nuclear Information System (INIS)

    Electro-oxidative lithography is used as a tool to create chemical nanostructures on an n-octadecyltrichlorosilane (OTS) monolayer self-assembled on silicon. The use of a bromine precursor molecule, which is exclusively assembled on these chemical templates, can be used to further functionalize the nanostructures by the site-selective generation of azide functions and performing the highly effective 1,3-dipolar cycloaddition reaction with acetylene functionalized molecules. The versatility of this reaction scheme provides the potential to integrate a large variety of functional molecules, to tailor the surface properties of the nanostructures or to anchor molecular building blocks or particles in confined, pre-defined surface areas. The results demonstrated in the present study introduce a conceivable route towards the functionalization of chemically active surface templates with high fidelity and reliability. It is demonstrated that surface features with a lateral resolution of 50 nm functionalized with propargyl alcohol can be fabricated.

  16. Comparison Of The Caused Physiologic Effects For The GAMMA Radiations And The Sodium Azide (NAN3) In Four Genotypes Of Wheat

    International Nuclear Information System (INIS)

    As it happens in many countries of the world. The wheat occupies an important line in the feeding of the Colombian town, what demands the continuous obtaining of new cultivations to assist the necessities of the farmers and consumers. The induction of mutations is a tool by means of which excellent results have been obtained in the improvement of cereals, especially in wheat, rice and barley, where mutants have been obtained that have been used directly by the farming ones and indirectly for the programs of improvement. Keeping in mind that in Colombia it is sought to use the induction of mutations in the programs of wheat improvement, and that it doesn't have deep investigations in this respect, it was solved to carry out the present work, where the main objective was to compare the tired physiologic effects after the treatment with different dose and concentrations of gamma rays and sodium azide in four genotypes of wheat of national interest. The work was carried out in two phases, the first one (generation M1) in the one that the seeds of the four genotypes were sowed (ICA-Tenza, Pav -76, Bonza-63 and Creole Pelao) tried with dose of 0, 10, 20, 30 and 40 krad of gamma rays and concentrations of 0, 0.1, 0.2, 0.3 and 0.4 m Molar of sodium azide. The data have more than enough emergency, plant height, longitude of the spike, grains/tassel number and weight of 100 grains, they were tabulated, processed and drawing for each one of the treatments being obtained this way, the radio curves and chemical- sensitivity. The second phase denominated generation M2, makes reference to the seeds coming from the plants M1, which were collected in form singular, taking 2 tassel/plant of the total of plants survivors planted in field

  17. Antioxidant activity and inhibition of aflatoxin B1-, nifuroxazide-, and sodium azide-induced mutagenicity by extracts from Rhamnus alaternus L.

    Science.gov (United States)

    Ammar, Rebai Ben; Sghaier, Mohamed Ben; Boubaker, Jihed; Bhouri, Wissem; Naffeti, Aicha; Skandrani, Ines; Bouhlel, Ines; Kilani, Soumaya; Ghedira, Kamel; Chekir-Ghedira, Leila

    2008-07-10

    The effect of extracts obtained from Rhamnus alaternus L. leaves on genotoxicity and SOS response induced by aflatoxin B(1) (10 microg/assay) as well as nifuroxazide (20 microg/assay) was investigated in a bacterial assay system, i.e., the SOS chromotest with Escherichia coli PQ37. The evaluation of the mutagenic and antimutagenic actions of the same extracts against the sodium azide (1.5 microg/plate)-induced mutagenicity was assayed using the Salmonella typhimurium assay system. The R. alaternus tested extracts exhibited no genotoxicity either with or without the external S9 activation mixture. However, all the extracts, particularly aqueous extract (A) and its chloroformic fraction (A(2)) significantly decreased the genotoxicity induced by aflatoxin B(1) and nifuroxazide. Moreover, the different extracts showed no mutagenicity when tested with Salmonella typhimurium strains TA1535 and TA1538 either with or without the S9 mix. Aqueous extract as well as its A(2) fraction exhibited the highest level of protection towards the direct mutagen, sodium azide-induced response in TA1535 strain with mutagenicity inhibition percentages of 83.6% and 91.4%, respectively, at a dose of 250 microg/plate. The results obtained by the Ames test assay confirm those of SOS chromotest. These same active extracts exhibited high xanthine oxidase (XOD) inhibiting with respective IC(50) values of 208 and 137 microg/ml, and superoxide anion-scavenging effects (IC(50) values of 132 and 117 microg/ml) when tested in the XOD enzymatic assay system. Our findings emphasize the potential of R. alaternus to prevent mutations and also its antioxidant effect. PMID:18511029

  18. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Atif Sarwar

    Full Text Available Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68 demonstrated the safety; suggesting that these derivatives could be

  19. Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

    International Nuclear Information System (INIS)

    In contrast to the neutral macrocycle [UN*2(N,C)] (1) [N* = N(SiMe3)3; N,C = CH2SiMe2N-(SiMe3)] which was quite inert toward I2, the anionic bismetallacycle [NaUN*(N,C)2] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me3Si)NSiMe2CH2CH2SiMe2N(SiMe3)] resulting from C-C coupling of the two CH2 groups, and [NaUN*(N,O)2] (3) [N,O = OC(=CH2)SiMe2N(SiMe3)], which is devoid of any U-C bond, was oxidized into the UV bismetallacycle [Na{UN*(N,O)2}2(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN3 or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN*2(N,C)(N3)] [M = Na, 7a or Na(15-crown-5), 7b], M[UN*2(N,C)(CN)] [M = NEt4, 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N3)2] [M = Na, 9a or Na(THF)4, 9b], [NEt4][UN*(N,N)(CN)2] (10), M[UN*(N,O)2(N3)] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O)2(CN)] [M = NEt4, 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral UV complex [U(N{SiMe3}-SiMe2C{CHI}O)2I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined. (authors)

  20. Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium.

    Science.gov (United States)

    Bénaud, Olivier; Berthet, Jean-Claude; Thuéry, Pierre; Ephritikhine, Michel

    2011-12-01

    In contrast to the neutral macrocycle [UN*(2)(N,C)] (1) [N* = N(SiMe(3))(3); N,C = CH(2)SiMe(2)N(SiMe(3))] which was quite inert toward I(2), the anionic bismetallacycle [NaUN*(N,C)(2)] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me(3)Si)NSiMe(2)CH(2)CH(2)SiMe(2)N(SiMe(3))] resulting from C-C coupling of the two CH(2) groups, and [NaUN*(N,O)(2)] (3) [N,O = OC(═CH(2))SiMe(2)N(SiMe(3))], which is devoid of any U-C bond, was oxidized into the U(V) bismetallacycle [Na{UN*(N,O)(2)}(2)(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN(3) or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN*(2)(N,C)(N(3))] [M = Na, 7a or Na(15-crown-5), 7b], M[UN*(2)(N,C)(CN)] [M = NEt(4), 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N(3))(2)] [M = Na, 9a or Na(THF)(4), 9b], [NEt(4)][UN*(N,N)(CN)(2)] (10), M[UN*(N,O)(2)(N(3))] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O)(2)(CN)] [M = NEt(4), 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral U(V) complex [U(N{SiMe(3)}SiMe(2)C{CHI}O)(2)I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined. PMID:22050237

  1. Chelator-Accelerated One-Pot ‘Click’ Labeling of Small Molecule Tracers with 2-[18F]Fluoroethyl Azide

    Directory of Open Access Journals (Sweden)

    Erik Årstad

    2013-05-01

    Full Text Available 2-[18F]Fluoroethyl azide ([18F]FEA can readily be obtained by nucleophilic substitution of 2-azidoethyl-4-toluenesulfonate with [18F]fluoride (half-life 110 min, and has become widely used as a reagent for ‘click’ labeling of PET tracers. However, distillation of [18F]FEA is typically required, which is time-consuming and unpractical for routine applications. In addition, copper(I-catalyzed cycloaddition of [18F]FEA with non-activated alkynes, and with substrates containing labile functional groups, can be challenging. Herein, we report a highly efficient and practical ligand-accelerated one-pot/two-step method for ‘click’ labeling of small molecule tracers with [18F]FEA. The method exploits the ability of the copper(I ligand bathophenanthrolinedisulfonate to accelerate the rate of the cycloaddition reaction. As a result, alkynes can be added directly to the crude reaction mixture containing [18F]FEA, and as cyclisation occurs almost immediately at room temperature, the reaction is tolerant to labile functional groups. The method was demonstrated by reacting [18F]FEA with a series of alkyne-functionalized 6-halopurines to give the corresponding triazoles in 55–76% analytical radiochemical yield.

  2. Phlomis mauritanica extracts reduce the xanthine oxidase activity, scavenge the superoxide anions, and inhibit the aflatoxin B1-, sodium azide-, and 4-nitrophenyldiamine-induced mutagenicity in bacteria.

    Science.gov (United States)

    Limem, Ilef; Bouhlel, Ines; Bouchemi, Meriem; Kilani, Soumaya; Boubaker, Jihed; Ben-Sghaier, Mohamed; Skandrani, Ines; Behouri, Wissem; Neffati, Aicha; Ghedira, Kamel; Chekir-Ghedira, Leila

    2010-06-01

    Four extracts were prepared from the leaves of Phlomis mauritanica: lyophilized infusion, total oligomer flavonoids, methanol, and ethyl acetate extracts. The antimutagenic properties of these extracts were investigated by assessing the inhibition of the mutagenic effects of direct-acting mutagens such as sodium azide and 4-nitrophenylenediamine and indirect-acting mutagens like aflatoxin B1 (AFB1) using the Ames assay. The four extracts prepared from P. mauritanica strongly inhibit the mutagenicity induced by AFB1 in both Salmonella typhimurium TA 100 and TA 98 assay systems. Lyophilized infusion and methanol extracts at the dose of 250 microg per plate reduced AFB1 mutagenicity by 93% and 91%, respectively, in S. typhymurium strain TA 100. We examined also the antioxidant effect of these extracts by the enzymatic xanthine/xanthine oxidase assay. Result indicated that total oligomer flavonoids and ethyl acetate and methanol extracts were potent inhibitors of xanthine oxidase activity. In contrast, lyophilized infusion, total oligomer flavonoids, and methanol extracts exhibited a high degree of superoxide anion scavenging. Our findings emphasize the potential of P. mauritanica extracts to prevent mutations and oxidant effects. Furthermore, the results presented here could be an additional argument to support the use of this species as a medicinal and dietary plant. PMID:20406134

  3. Anti-inflammatory drugs interacting with Zn (II) metal ion based on thiocyanate and azide ligands: Synthesis, spectroscopic studies, DFT calculations and antibacterial assays

    Science.gov (United States)

    Chiniforoshan, Hossein; Tabrizi, Leila; Hadizade, Morteza; Sabzalian, Mohammad R.; Chermahini, Alireza Najafi; Rezapour, Mehdi

    2014-07-01

    Zinc (II) complexes with non-steroidal anti-inflammatory drugs (NSAIDs) naproxen (nap) and ibuprofen (ibu) were synthesized in the presence of nitrogen donor ligands (thiocyanate or azide). The complexes were characterized by elemental analysis, FT-IR, 1H NMR and UV-Vis spectroscopes. The binding modes of the ligands in complexes were established by means of molecular modeling of the complexes, and calculation of their IR, NMR and absorption spectra at DFT (TDDFT)/B3LYP level were studied. The experimental and calculated data verified monodentate binding through the carboxylic oxygen atoms of anti-inflammatory drugs in the zinc complexes. The calculated 1H, FT-IR and UV-Vis data are in better agreement with the experimental results, and confirm the predicted tetrahedral structures for the Zn (II) complexes. In addition to DFT calculations of complexes, natural bond orbital (NBO) was performed at B3LYP/6-31+G(d,p) level of theory. Biological studies showed the antibacterial activity of zinc complexes against Gram-positive and Gram-negative bacterial strains.

  4. Studies on the rice seed (Oryza sativa) sensitivity to gama radiation, neutrons di-enthyl sulphate (DES) and sodium azide (SA)

    International Nuclear Information System (INIS)

    Dry rice seeds of 'Dourado Precoce' variety were treated with gama-rays, thermal and fast neutrons, di-ethyl sulphate (DES) and sodium azide (SA). Biologial effects on survival, seedling height, plant fertility and chlorophy 11 mutation frequency were studied in the M1 generation. The data obtained were analysed by 'independent test'. Survival was not affected by increased gama ray dosage, but by increased DES and SA dosages, as well as by SA treatments with increased solution acidity for seeds pretreated in distilled water. Seedling height was decreased with the increase of gama-ray dosage, DES concentration. SA acidity and concentration. Plant fertility was reduced drastically with higher gama-ray and neutron dosages and with high SA acidity and concentrations. The maximum chlorophy 11 mutation frequency was obtained in the SA treatment. Seeds pretreated with distilled water showed larger physiological damages in the SA treatments and higher mutation frequencies. Regarding chlorophyll mutation frequency, thermal neutrons were more efficient than gama-rays. SA was the most efficient mutagen used . DES showed lower physiological damages in the M1 plants, but did not induce mutations in the used conditions

  5. Electronic Structure of Manganese Complexes of the Redox-Non-innocent Tetrazene Ligand and Evidence for the Metal-Azide/Imido Cycloaddition Intermediate.

    Science.gov (United States)

    Vaddypally, Shivaiah; McKendry, Ian G; Tomlinson, Warren; Hooper, Joseph P; Zdilla, Michael J

    2016-07-18

    The first synthetic manganese tetrazene complexes are described as a redox pair comprising anionic [Mn(N4 Ad2 )2 ](-) (1) and neutral Mn(N4 Ad2 )2 (2) complexes (N4 Ad2 =[Ad-N-N=N-N-Ad](2-) ). Compound 1 is obtained in two forms as lithium salts, one as a cationic Li2 Mn cluster, and one as a Mn-Li 1D ionic polymer. Compound 1 is electronically described as a Mn(III) center with two [N4 Ad2 ](2-) ligands. The one-electron oxidized 2 is crystalized in two morphologies, one as pure 2 and one as an acetonitrile adduct. Despite similar composition, the behavior of 2 differs in the two morphologies. Compound 2-MeCN is relatively air and temperature stable. Crystalline 2, on the other hand, exhibits a compositional, dynamic disorder wherein the tetrazene metallacycle ring-opens into a metal imide/azide complex detectable by X-ray crystallography and FTIR spectroscopy. Electronic structure of 2 was examined by EPR and XPS spectroscopies and DFT calculations, which indicate 2 is best described as a Mn(III) ion with an anion radical delocalized across the two ligands through spin-polarization effects. PMID:27339316

  6. Detection of nearest neighbors to specific fluorescently tagged ligands in rod outer segment and lymphocyte plasma membranes by photosensitization of 5-iodonaphthyl 1-azide

    International Nuclear Information System (INIS)

    Lima bean agglutinin-fluorescein 5-isothiocyanate conjugate (FluNCS-lima bean lectin) interacts with specific receptor molecules on membranes both from the rod outer segment (ROS) of the frog retina and from S49 mouse lymphoma cells. When [125I]-5-iodonaphthyl 1-azide (125I-INA), which freely and randomly partitions into the lipid bilayer, is added to membranes and the suspension is irradiated at 480 nm, the FluNCS-conjugated lectin photosensitizes the [125I]INA but only at discrete sites. This results in the selective labeling of specific proteins: an 88-kDa protein on ROS membranes and a 56-kDa protein on S49 plasma membranes. Labeling is dependent upon the interaction of the FluNCS-lectin with glycosylated receptor sites, since N-acetylgalactosamine, but not methyl alpha-mannoside, blocked labeling of the 56-kDa protein on S49 membranes. In contrast, a random labeling pattern of membrane proteins was observed upon irradiation at 480 nm using other fluorescein conjugates, such as FluNCS-bovine serum albumin (FluNCS-BSA) or FluNCS-soybean trypsin inhibitor (FluNCS-STI), which interact with cell membranes in a nonselective manner, or with N-(fluorescein-5-thiocarbamoyl)-n-undecyclamine (FluNCS-NHC11), which is freely miscible in the membrane lipid. Random labeling was also obtained by direct photoexcitation of [125I]INA at 314 nm, with no distinct labeling of the 88- and 56-kDa proteins in the respective membranes. These results suggest that protein ligands can be used to guide sensitizers to discrete receptor sites and lead to their selective labeling by photosensitized activation of [125I]INA

  7. Detection of nearest neighbors to specific fluorescently tagged ligands in rod outer segment and lymphocyte plasma membranes by photosensitization of 5-iodonaphthyl 1-azide

    Energy Technology Data Exchange (ETDEWEB)

    Raviv, Y.; Bercovici, T.; Gitler, C.; Salomon, Y. (Weizmann Institute of Science, Rehovot (Israel))

    1989-02-07

    Lima bean agglutinin-fluorescein 5-isothiocyanate conjugate (FluNCS-lima bean lectin) interacts with specific receptor molecules on membranes both from the rod outer segment (ROS) of the frog retina and from S49 mouse lymphoma cells. When (125I)-5-iodonaphthyl 1-azide (125I-INA), which freely and randomly partitions into the lipid bilayer, is added to membranes and the suspension is irradiated at 480 nm, the FluNCS-conjugated lectin photosensitizes the (125I)INA but only at discrete sites. This results in the selective labeling of specific proteins: an 88-kDa protein on ROS membranes and a 56-kDa protein on S49 plasma membranes. Labeling is dependent upon the interaction of the FluNCS-lectin with glycosylated receptor sites, since N-acetylgalactosamine, but not methyl alpha-mannoside, blocked labeling of the 56-kDa protein on S49 membranes. In contrast, a random labeling pattern of membrane proteins was observed upon irradiation at 480 nm using other fluorescein conjugates, such as FluNCS-bovine serum albumin (FluNCS-BSA) or FluNCS-soybean trypsin inhibitor (FluNCS-STI), which interact with cell membranes in a nonselective manner, or with N-(fluorescein-5-thiocarbamoyl)-n-undecyclamine (FluNCS-NHC11), which is freely miscible in the membrane lipid. Random labeling was also obtained by direct photoexcitation of (125I)INA at 314 nm, with no distinct labeling of the 88- and 56-kDa proteins in the respective membranes. These results suggest that protein ligands can be used to guide sensitizers to discrete receptor sites and lead to their selective labeling by photosensitized activation of (125I)INA.

  8. Utilizing copper(I) catalyzed azide-alkyne Huisgen 1,3-dipolar cycloaddition for the surface modification of colloidal particles with electroactive and emissive moieties

    Science.gov (United States)

    Rungta, Parul

    " chemistry; Aqueous-phase 83 nm poly(propargyl acrylate) (PA) nanoparticles were surface-functionalized with sparingly water soluble fluorescent moieties through a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) (i.e., "click" transformation) to produce fluoroprobes with a large Stokes shift. For moieties which could not achieve extensive surface coverage on the particles utilizing a standard click transformation procedure, the presence of beta-cyclodextrin (beta-CD) during the transformation enhanced the grafting density onto the particles. For an oxadiazole containing molecule (AO), an azide-modified coumarin 6 (AD1) and a polyethylene glycol modified naphthalimide-based emitter (AD2), respectively, an 84%, 17% and 5% increase in the grafting densities were observed, when the transformation was performed in the presence of beta-CD. In contrast, a carbazolyl-containing moiety (AC) exhibited a slight retardation in the final grafting density when beta-CD was employed. Photoluminescence studies indicated that AC & AO when attached to the particles form an exciplex. An efficient energy transfer from the exciplex to the surface attached AD2 resulted in a total Stokes shift of 180 nm for the modified particles. (3) The synthesis and characterization of near-infrared (NIR) emitting particles for potential applications in cancer therapy. PA particles were surface modified through the "click" transformation of an azide-terminated indocyanine green (azICG), an NIR emitter, and poly(ethylene glycol) (azPEG) chains of various molecular weights. The placement of azICG onto the surface of the particles allowed for the chromophores to complex with bovine serum albumin (BSA) when dispersed in PBS that resulted in an enhancement of the dye emission. In addition, the inclusion of azPEG with the chromophores onto the particle surface resulted in a synergistic nine-fold enhancement of the fluorescence intensity, with azPEGs of increasing molecular weight amplifying the response

  9. L-Proline catalyzed one-step synthesis of 4,5-diaryl-2H-1,2,3-triazoles from heteroaryl cyanostilbenes via [3+2] cycloaddition of azide

    OpenAIRE

    Penthala, Narsimha Reddy; Madadi, Nikhil Reddy; Janganati, Venumadhav; Crooks, Peter A.

    2014-01-01

    Use of a novel reagent has been established for the synthesis of a series of 4,5-diaryl-2H-1,2,3-triazoles (6a-i and 9a-e) from cyanostilbene analogs of benzo[b]thiophene, benzo[b]furan and indole, catalyzed by L-proline via Lewis base-catalyzed one-step [3+2]cycloaddition of azide. This method provides an efficient, simple and environmentally benign procedure that affords good yields and relatively short reaction times.

  10. Synthesis, characterization and crystal structure determination of Mn (II) ion based 1D polymer constructed from 2, 2′ bipyridyl and azide group, its thermal stability, magnetic properties and Hirshfeld surface analysis

    International Nuclear Information System (INIS)

    The 1-D polymeric complex (I) is having formula [Mn(2,2′-BP).(N3)2]n, which has been crystallized in distilled water and characterized by elemental analyses, FT-IR spectrum, powder X-ray diffraction analyses and single-crystal diffraction analysis. This polymer possesses 1D helical chains or coils where Mn–azide–Mn forms the base of the coil which is alternatively garlanded by rigid bi-pyridine rings, where coordinates are in anti-fashion. The Mn (II) ions in the repeating units are linked by two end-on azide groups which extend through the two end-to-end azide ligands to the next unit forming a 1-D polymeric chain. The present study suggests that the use of this rigid and neutral building block leads to give better arrangement of the polymeric motif with [010] chains in 2-c uninodal net. During investigation of strong or weak intermolecular interactions, X-ray diffraction analysis and Hirshfeld surface analysis give rise to comparable results but in Hirshfeld surface analysis, two-third times more results of close contacts are obtained. The fingerprint plots demonstrate that these weak non-bonding interactions are important for stabilizing the crystal packing. Magnetic properties of the complex (I) were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of Mn (II) ions. The J-exchange parameters found are J1=64.3 K (45.3 cm−1), and J2=−75.7 K (−53.3 cm−1). Magnetic properties are discussed in comparison with those of other similar molecular magnets of [Mn(L–L)(N3)2]n type. - - Highlights: • Synthesized 1-D polymeric complex of Mn (II) ions with 2, 2′ bipyridyl and azide group. • X-ray data of complex (I) is in a good agreement with TGA and other spectroscopic techniques. • DFT calculations were done and compared with the parameter of experimental and theoretical data. • Intermolecular interactions calculated by Hirshfeld surface analysis compared with X-ray data

  11. Azid sodný a animální modely Alzheimerovy nemoci. Část I – chronická subkutánní aplikace mladým zvířatům, behaviorální testy a biochemická analýza mozku mladých zvířat

    Czech Academy of Sciences Publication Activity Database

    Krištofíková, Z.; Ort, Michael; Helešic, V.; Bureš, Jan; Řípová, D.

    2006-01-01

    Roč. 10, č. S3 (2006), s. 39-42. ISSN 1211-7579 R&D Projects: GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z50110509 Keywords : sodium azide * Alzheimer disease * animal model Subject RIV: FH - Neurology

  12. Green synthesis of copper nanoparticles using Ginkgo biloba L. leaf extract and their catalytic activity for the Huisgen [3+2] cycloaddition of azides and alkynes at room temperature.

    Science.gov (United States)

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad

    2015-11-01

    During this study, we report the green synthesis of copper nanoparticles (Cu NPs) using Ginkgo biloba L. leaf extract as a reducing and stabilizing agent under surfactant-free conditions. The formation of Cu NPs is monitored by recording the UV-vis absorption spectra. The green synthesized Cu NPs are characterized by TEM, EDS, FT-IR and UV-visible techniques. According to UV-vis results, the synthesized Cu NPs by this method are quite stable even after one month indicating the stability of Cu NPs. In terms of environmental impact and economy, metallic Cu NPs offer several advantages over homogeneous and traditional heterogeneous catalysts. In addition, due to the increased metal surface area, Cu NPs shows very high catalytic activity for the Huisgen [3+2] cycloaddition of azides and alkynes at room temperature. Furthermore, the catalyst can be simply recovered and reused several times with almost no loss in activity. PMID:26164245

  13. Mn(II)- and Co(II)-Catalyzed Transformation of 2-Cyanopyrimidine to Methylimidate by Sodium Azide: Isolation, Structural Characterization, and Magnetic Studies on 2D Mn(II)- and Cu(II)-Complexes.

    Science.gov (United States)

    Dolai, Malay; Biswas, Surajit; Escuer, Albert; Ali, Mahammad

    2015-07-20

    The Mn(II)-mediated transformation of 2-cyanopyrimidine to methylimidate in the presence of inorganic azide is proven through isolation and structural characterization of a metal complex. Though the reaction conditions are favorable for a "click" reaction leading to the formation of tetrazole, as evidenced from recent studies, we are astonished to see the formation of methylimidate in MeOH instead of tetrazole, which is supposed to form only in the presence of catalytic amount of corresponding alkoxide ion as base. The catalytic nature of this transformation reaction was confirmed by performing these experiments under catalytic conditions and analyzing the products using liquid chromatography-mass spectrometry techniques, which clearly showed ∼96% and ∼60% selectivity of methylimidate along with almost 100% conversion in the presence of Mn(II) and Co(II) as catalysts, respectively. In absence or presence of other metal ions like Cu(II), Ni(II), Fe(II), Zn(II), etc. only tetrazole formation takes place. So the present findings extended the formation of methylimidate catalyzed by metal ions in the presence of azide ion in alcoholic medium. Importantly, a probable mechanism for this unexpected transformation was framed based on the structural analysis and high-resolution mass spectrometry (electrospray ionization MS(+)) studies. The magnetic studies were also performed on complexes [Mn(L)(N3)2]n (1) and [Cu (L(2))2]n (2a), showing anti-ferromagnetic character for compound 1 and negligible coupling for the copper complex 2a. PMID:26135905

  14. Azid sodný a animální modely demence Alzheimerova typu. Část II – Chronická subkutánní aplikace mladým i starým zvířatům, shrnutí výsledků

    Czech Academy of Sciences Publication Activity Database

    Krištofíková, Z.; Ort, Michael; Helešic, V.; Vrbacký, Marek; Majer, E.; Bureš, Jan; Stuchlík, Aleš; Řípová, D.

    2007-01-01

    Roč. 11, Suppl.3 (2007), s. 30-33. ISSN 1211-7579. [Konference Centra neuropsychiatrických studií - Neurologie v klinické aplikaci /7./. Zdoňov, 03.10.2007-05.10.2007] R&D Projects: GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z50110509 Keywords : Sodium azide * Alzheimer’s dementia * memory Subject RIV: FH - Neurology

  15. Synthesis of 14C-labelled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), nitrocellulose (NC) and glycidyl azide polymer (GAP) for use in assessing the biodegradation potential of these energetic compounds

    International Nuclear Information System (INIS)

    Within the framework of an R and D project on bioremediation of soils contaminated with energetic compounds, the biodegradation of energetic products such as hexogen (RDX), trinitrotoluene (TNT), nitrocellulose (NC) and glycidyl azide polymer (GAP) is under study. Microcosm assays must be performed with radioactive carbon-14 labelled products in order to follow the biodegradation process. 14C-RDX was prepared by nitration of hexamethylenetetramine (HMTA) according to the Hale process. 14C-ring and methyl labelled TNTs synthesized according to the Dorey and Carper procedure. 14C-cellulose was synthesized from 14C-glucose by Acetobacter xylinum. Nitration of the 14C-cellulose yielded 14C-nitrocellulose. 14C-glycidyl azide polymer was obtained by polymerization and azidation of 14C-epichlorohydrin (ECH) which was synthesized from 14C-glycerol. Hydrochlorination of 14C-glycerol and epoxidation of the resulting 14C-1,3-dichloro 2-propanol yielded 14C-ECH. The syntheses of these 14C-labelled explosives are described in this paper. (Author)

  16. Synthesis of a tritium labeled tetrafluoro-substituted aryl azide photoaffinity labeling agent for chloride channels. Application of [3H]-sodium borohydride-cobalt chloride to tritium labeling

    International Nuclear Information System (INIS)

    5-Nitro-2-[N-3-(4-azido-2,3,5,6-tetrafluorophenyl)-propylamino]-benzoic acid (FAzNPPB), a photoaffinity analog of the potent epithelial chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) has been prepared in five steps from commercially available 4-amino-2,3,5,6-tetrafluorobenzonitrile. The main feature of this synthesis was the use of NaBH4-CoCl2 to convert an aryl-substituted alkenyl nitrile precursor to the corresponding alkyl amine. The feasibility of this approach and the stoichiometry were developed by model work with cinnamonitrile. Using sodium borotritide-cobalt chloride, [3H]-FAzNPPB (specific activity 13.9 mCi/mmol, radiochemical purity >99%) was prepared in three steps from (E)-4-amino-2,3,5,6-tetrafluoro-cinnamonitrile. [3H]-Sodium borohydride, cobalt chloride, azide, photaffinity, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB). (author)

  17. Synthesis, Spectroscopy, Theoretical, and Electrochemical Studies of Zn(II, Cd(II, and Hg(II Azide and Thiocyanate Complexes of a New Symmetric Schiff-Base Ligand

    Directory of Open Access Journals (Sweden)

    Morteza Montazerozohori

    2013-01-01

    Full Text Available Synthesis of zinc(II/cadmium(II/mercury(II thiocyanate and azide complexes of a new bidentate Schiff-base ligand (L with general formula of MLX2 (M = Zn(II, Cd(II, and Hg(II in ethanol solution at room temperature is reported. The ligand and metal complexes were characterized by using ultraviolet-visible (UV-visible, Fourier transform infrared (FT-IR, 1H- and 13C-NMR spectroscopy and physical characterization, CHN analysis, and molar conductivity. 1H- and 13C-NMR spectra have been studied in DMSO-d6. The reasonable shifts of FT-IR and NMR spectral signals of the complexes with respect to the free ligand confirm well coordination of Schiff-base ligand and anions in an inner sphere coordination space. The conductivity measurements as well as spectral data indicated that the complexes are nonelectrolyte. Theoretical optimization on the structure of ligand and its complexes was performed at the Becke’s three-parameter hybrid functional (B3 with the nonlocal correlation of Lee-Yang-Parr (LYP level of theory with double-zeta valence (LANL2DZ basis set using GAUSSIAN 03 suite of program, and then some theoretical structural parameters such as bond lengths, bond angles, and torsion angles were obtained. Finally, electrochemical behavior of ligand and its complexes was investigated. Cyclic voltammograms of metal complexes showed considerable changes with respect to free ligand.

  18. Ligand Synthesis Catalyst and Complex Metal Ion: Multicomponent Synthesis of 1,3-Bis(4-phenyl-[1,2,3]triazol-1-yl-propan-2-ol Copper(I Complex and Application in Copper-Catalyzed Alkyne-Azide Cycloaddition

    Directory of Open Access Journals (Sweden)

    María Teresa Ramírez-Palma

    2016-01-01

    Full Text Available A new bistriazole copper complex was synthesized by direct treatment of an alkyne, an azide, and CuI as copper salt through in situ ligand formation under a multicomponent reaction process. This complex was analyzed by XPS, TGA, DSC, and SEM techniques and revealed a triangular-shaped morphology, high thermal stability, and catalytic power in CuAAC reactions, requiring only 2.5% mol catalyst to afford 1,2,3-triazoles in good yields which can be reused at least for 4 cycles.

  19. Azide Binding Controlled by Steric Interactions in Second Sphere. Synthesis, Crystal Structure, and Magnetic Properties of [Ni(II)2(L)(μ1,1-N3)][ClO4] (L = Macrocyclic N6S2 Ligand).

    Science.gov (United States)

    Jeremies, Alexander; Gruschinski, Sina; Meyer, Michel; Matulis, Vitaly; Ivashkevich, Oleg A; Kobalz, Karolin; Kersting, Berthold

    2016-02-15

    The dinuclear Ni(II) complex [Ni2(L(2))][ClO4]2 (3) supported by the 28-membered hexaaza-dithiophenolate macrocycle (L(2))(2-) binds the N3(-) ion specifically end-on yielding [Ni2(L(2))(μ1,1-N3)][ClO4] (7) or [Ni2(L(2))(μ1,1-N3)][BPh4] (8), while the previously reported complex [Ni2L(1)(μ1,3-N3)][ClO4] (2) of the 24-membered macrocycle (L(1))(2-) coordinates it in the end-to-end fashion. A comparison of the X-ray structures of 2, 3, and 7 reveals the form-selective binding of complex 3 to be a consequence of its preorganized, channel-like binding pocket, which accommodates the azide anion via repulsive CH···π interactions in the end-on mode. In contrast to [Ni2L(1)(μ1,3-N3)][ClO4] (2), which features a S = 0 ground state, [Ni2(L(2))(μ1,1-N3)][BPh4] (8) has a S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and azido bridges with a value for the magnetic exchange coupling constant J of 13 cm(-1) (H = -2JS1S2). These results are further substantiated by density functional theory calculations. The stability of the azido-bridged complex determined by isothermal titration calorimetry in MeCN/MeOH 1/1 v/v (log K11 = 4.88(4) at I = 0.1 M) lies in between those of the fluorido- (log K11 = 6.84(7)) and chlorido-bridged complexes (log K11 = 3.52(5)). These values were found to compare favorably well with the equilibrium constants derived at lower ionic strength (I = 0.01 M) by absorption spectrophotometry (log K11 = 5.20(1), 7.77(9), and 4.13(3) for N3(-), F(-), and Cl(-) respectively). PMID:26836637

  20. FT-IR Study on the Catalytic Reaction Kinetics of Glycidyl Azide Polymer with N100%FT-IR 法研究 GAP 与 N100的催化反应动力学

    Institute of Scientific and Technical Information of China (English)

    申飞飞; Abbas Tanver; 罗运军

    2014-01-01

    The reaction kinetics of glycidyl azide polymer (GAP)with polyisocyanate (N100)was studied by the FT-IR method.Using triphenyl bismuth(TPB)and di-n-butyltin dilaurate (T12)as catalysts,the reaction mecha-nism function and activation energies of the two systems at 60,70,80 and 90℃ were obtained.The results show that the curing reaction of GAP/N100 system is determined as first order reaction.When the content of TPB and T12 is 0.015%,respectively,the whole curing reaction process using TPB as catalyst obeys the first-order kinetic law,the system using T12 as catalyst obeys the first-order kinetic law and the reaction mechanism function is g(α)=-ln(1 -α)when the degree of conversation is less than 80%,while the system obeys three-dimensional (spheri-cal symmetric)diffusion and the reaction mechanism function is g(α)=[1 -(1-α)1/3 ]2 when the degree of conver-sation is over 80%.The curing reaction time of GAP/N100 using T12 as catalyst is much less than that of GAP/N100 using TPB as catalyst.%采用傅里叶变换红外(FT-IR)研究了聚叠氮缩水甘油醚(GAP)与多异氰酸酯(N100)之间的反应动力学。得到60、70、80、90℃下分别用 TPB(三苯基铋)和 T12(二月桂酸二丁基锡)作催化剂时体系的反应机理函数和表观活化能。结果表明,GAP/N100体系的固化反应为一级动力学反应;当两种固化催化剂质量分数均为0.015%,以TPB 为催化剂时体系整个固化过程遵循一级动力学规律;以 T12为催化剂时,在转化率达80%之前,体系遵循一级反应规律,反应机理函数为 g(α)=-ln(1-α),之后反应机理函数转变为三维(球对称)扩散 g(α)=[1-(1-α)1/3]2;用 T12作催化剂时,GAP/N100固化反应结束时间远低于用 TPB 作催化剂时所用时间。

  1. Activation of 5-[125I]iodonaphthyl-1-azide via excitation of fluorescent (N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)) lipid analogs in living cells. A potential tool for identification of compartment-specific proteins and proteins involved in intracellular transport and metabolism of lipids

    International Nuclear Information System (INIS)

    We describe a new technique for analysis of proteins located near fluorescent lipid analogs in intact living cells using the membrane-permeant, photoactivatable probe, 5-[125I]iodonaphthyl-1-azide ([125I]INA). [125I] INA can be activated directly with UV light or indirectly through excitation of adjacent fluorophores (photosensitizers) with visible light to modify nearby proteins covalently with 125I. In this report we demonstrate that fluorescent phospholipids and sphingolipids containing N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-6-aminocaproic acid serve as appropriate photosensitizers for [125I]INA. Using Chinese hamster ovary fibroblasts, we optimized the labeling conditions with respect to lipid concentration and time of irradiation and then examined the profiles of cellular proteins that were labeled when fluorescent analogs of ceramide, sphingomyelin, and phosphatidic acid were used as photosensitizers in living cells. The use of different fluorescent lipids, which label different subcellular compartments of cells as determined by fluorescence microscopy, derivatized different sets of cellular proteins with 125I. The labeled proteins were subsets of the total set of proteins available for derivatization as determined by direct activation of [125I]INA. Most proteins labeled by this procedure were pelleted by centrifugation of cell lysates at high speed (260,000 x g), but several soluble proteins were also labeled under these conditions. The implications of using this technique for identification of compartment-specific proteins and proteins involved in lipid metabolism and transport are discussed

  2. Glycidyl Azide Polymer-based Enhanced Energy LOVA Gun Propellant

    Directory of Open Access Journals (Sweden)

    R. R. Sanghavi

    2006-07-01

    Full Text Available In this study, cyclotrimethylene trinitramine propellants with triacetin (TA-plasticisedcellulose acetate (CA and nitrocellulose (NC combination as binders were evaluated for lowvulnerable ammunition (LOVA. Triacetin was replaced by energetic plasticiser; glycidyl azidepolymer (GAP in increments to enhance the performance in terms of force constant . In additionto ballistics, parameters like vulnerability, mechanical and thermal properties of GAP-basedpropellants in comparison to those of TA-based propellants, were also determined. The studybrings out that the incorporation of 2-6 per cent GAP in place of TA resulted in the enhancementof force constant by 22-70 J/g and improved overall combustion characteristics. DSC revealedthat thermal decomposition of GAP-LOVA propellants evolved more energy than TA-LOVApropellants. GAP-based LOVA propellant similar to TA-plasticised LOVA propellant, was foundsuperior to NQ propellant in vulnerability tests as well as in hot fragment conductive ignition(HFCI studies. As regards mechanical properties, incorporation of GAP resulted in improvedcompression strength.

  3. Glycidyl Azide Polymer-based Enhanced Energy LOVA Gun Propellant

    OpenAIRE

    R. R. Sanghavi; P. J. Kamale; M.A.R. Shaikh; T. K. Chakraborthy; S. N. Asthana; Amarjit Singh

    2006-01-01

    In this study, cyclotrimethylene trinitramine propellants with triacetin (TA)-plasticisedcellulose acetate (CA) and nitrocellulose (NC) combination as binders were evaluated for lowvulnerable ammunition (LOVA). Triacetin was replaced by energetic plasticiser; glycidyl azidepolymer (GAP) in increments to enhance the performance in terms of force constant . In additionto ballistics, parameters like vulnerability, mechanical and thermal properties of GAP-basedpropellants in comparison to those o...

  4. Molecular and electronic structure of chromium(V) nitrido complexes with azide and isothiocyanate ligands

    DEFF Research Database (Denmark)

    Bendix, Jesper; Birk, Torben; Weyhermüller, Thomas

    2005-01-01

    ligators. This absorption provides the spectrochemical series for the equatorial ligands, which is found to be numerically almost identical to that determined for chromium(III). DFT calculations reproduce the observed structures and corroborate the ligand field picture of the electronic structure of these...

  5. Azide binding to the trinuclear copper center in laccase and ascorbate oxidase

    DEFF Research Database (Denmark)

    Gromov, I; Marchesini, A; Farver, O;

    1999-01-01

    distance between the dipolar coupled Cu(II) pair is shorter in laccase than in AO. The proximity of T2 Cu(II) to the S = 1 Cu(II) pair enhances its relaxation rate, reducing its signal intensity relative to that of native protein. The disruption of the T3 anti-ferromagnetic coupling occurs only in part of...

  6. Gas phase uranyl activation: formation of a uranium nitrosyl complex from uranyl azide.

    Science.gov (United States)

    Gong, Yu; de Jong, Wibe A; Gibson, John K

    2015-05-13

    Activation of the oxo bond of uranyl, UO2(2+), was achieved by collision induced dissociation (CID) of UO2(N3)Cl2(-) in a quadrupole ion trap mass spectrometer. The gas phase complex UO2(N3)Cl2(-) was produced by electrospray ionization of solutions of UO2Cl2 and NaN3. CID of UO2(N3)Cl2(-) resulted in the loss of N2 to form UO(NO)Cl2(-), in which the "inert" uranyl oxo bond has been activated. Formation of UO2Cl2(-) via N3 loss was also observed. Density functional theory computations predict that the UO(NO)Cl2(-) complex has nonplanar Cs symmetry and a singlet ground state. Analysis of the bonding of the UO(NO)Cl2(-) complex shows that the side-on bonded NO moiety can be considered as NO(3-), suggesting a formal oxidation state of U(VI). Activation of the uranyl oxo bond in UO2(N3)Cl2(-) to form UO(NO)Cl2(-) and N2 was computed to be endothermic by 169 kJ/mol, which is energetically more favorable than formation of NUOCl2(-) and UO2Cl2(-). The observation of UO2Cl2(-) during CID is most likely due to the absence of an energy barrier for neutral ligand loss. PMID:25906363

  7. Gas Phase Uranyl Activation: Formation of a Uranium Nitrosyl Complex from Uranyl Azide

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; De Jong, Wibe A.; Gibson, John K.

    2015-05-13

    Activation of the oxo bond of uranyl, UO22+, was achieved by collision induced dissociation (CID) of UO2(N3)Cl2– in a quadrupole ion trap mass spectrometer. The gas phase complex UO2(N3)Cl2– was produced by electrospray ionization of solutions of UO2Cl2 and NaN3. CID of UO2(N3)Cl2– resulted in the loss of N2 to form UO(NO)Cl2–, in which the “inert” uranyl oxo bond has been activated. Formation of UO2Cl2– via N3 loss was also observed. Density functional theory computations predict that the UO(NO)Cl2– complex has nonplanar Cs symmetry and a singlet ground state. Analysis of the bonding of the UO(NO)Cl2– complex shows that the side-on bonded NO moiety can be considered as NO3–, suggesting a formal oxidation state of U(VI). Activation of the uranyl oxo bond in UO2(N3)Cl2– to form UO(NO)Cl2– and N2 was computed to be endothermic by 169 kJ/mol, which is energetically more favorable than formation of NUOCl2– and UO2Cl2–. The observation of UO2Cl2– during CID is most likely due to the absence of an energy barrier for neutral ligand loss.

  8. Synthesis of alpha-tetrasubstituted triazoles by copper-catalyzed silyl deprotection/azide cycloaddition

    OpenAIRE

    Zachary L. Palchak; Nguyen, Paula T; Larsen, Catharine H

    2015-01-01

    Propargylamines are popular substrates for triazole formation, but tetrasubstituted variants have required multistep syntheses involving stoichiometric amounts of metal. A recent cyclohexanone–amine–silylacetylene coupling forms silyl-protected tetrasubstituted propargylamines in a single copper-catalyzed step. The development of the tandem silyl deprotection–triazole formation reported herein offers rapid access to alpha-tetrasubstituted triazoles. A streamlined two-step approach to this unc...

  9. Synthesis of alpha-tetrasubstituted triazoles by copper-catalyzed silyl deprotection/azide cycloaddition

    Directory of Open Access Journals (Sweden)

    Zachary L. Palchak

    2015-08-01

    Full Text Available Propargylamines are popular substrates for triazole formation, but tetrasubstituted variants have required multistep syntheses involving stoichiometric amounts of metal. A recent cyclohexanone–amine–silylacetylene coupling forms silyl-protected tetrasubstituted propargylamines in a single copper-catalyzed step. The development of the tandem silyl deprotection–triazole formation reported herein offers rapid access to alpha-tetrasubstituted triazoles. A streamlined two-step approach to this uncommon class of hindered triazoles will accelerate exploration of their therapeutic potential. The superior activity of copper(II triflate in the formation of triazoles from sensitive alkyne substrates extends to simple terminal alkynes.

  10. Construction of a Multifunctional Enzyme Complex via the Strain-Promoted Azide-Alkyne Cycloaddition

    NARCIS (Netherlands)

    Schoffelen, S.; Beekwilder, M.J.; Debets, M.F.; Bosch, H.J.; Hest, van J.C.M.

    2013-01-01

    Inspired by the multienzyme complexes occurring in nature, enzymes have been brought together in vitro as well. We report a co-localization strategy milder than nonspecific cross-linking, and free of any scaffold and affinity tags. Using non-natural amino acid incorporation, two heterobifunctional l

  11. Catalytic behavior of surfactant-containing-MCM-41 mesoporous materials for cycloaddition of 4-nitrophenyl azide

    OpenAIRE

    Boukoussa, Bouhadjar; Zeghada, Sarah; Bentabed-Ababsa, Ghenia; Hamacha, Rachida; Derdour, Aïcha; BENGUEDDACH Abdelkader; Mongin, Florence

    2014-01-01

    Si-MCM-41, Ga-MCM-41 and Al-MCM-41 mesoporous catalysts (with Si/Al = 80 and Si/Ga = 80) were prepared by direct synthesis under hydrothermal crystallization method using sodium aluminate or gallium sulfate and tetraethyl orthosilicate (TEOS) as aluminum or gallium and silica sources, respectively. The structural features of the materials were determined by various physico-chemical techniques such as X-ray diffraction (XRD), nitrogen sorption at 77 K, Fourier transform infrared spectroscopy (...

  12. Synthesis of Dendronized Poly(l-Glutamate) via Azide-Alkyne Click Chemistry

    OpenAIRE

    Peter Perdih; Andrej Kržan; Ema Žagar

    2016-01-01

    Poly(l-glutamate) (PGlu) was modified with a second-generation dendron to obtain the dendronized polyglutamate, P(Glu-D). Synthesized P(Glu-D) exhibited a degree of polymerization (DPn) of 46 and a 43% degree of dendronization. Perfect agreement was found between the P(Glu-D) expected structure and the results of nuclear magnetic resonance spectroscopy (NMR) and size-exclusion chromatography coupled to a multi-angle light-scattering detector (SEC-MALS) analysis. The PGlu precursor was modifie...

  13. Preparation and NMR characterization of glucosamine oligomers bearing an azide function using chitosan.

    Science.gov (United States)

    Maria Marzaioli, Alberto; Bedini, Emiliano; Lanzetta, Rosa; Perino, Vincenzo; Parrilli, Michelangelo; De Castro, Cristina

    2012-10-01

    In this study, a procedure to produce glucosamine oligomers with the amino functions transformed into azido groups was optimized, and HPLC purification afforded to the isolation of nine different oligosaccharides derivatives, with the reducing end transformed in alditol. These oligomers differed for the degree of polymerization and for the type of alditol at the reducing end. The first group comprehended species from di- to hexasaccharide, with all the amino functions converted into an azido group. The second and the third groups were isolated in minor yields, and were both constituted from tri- and tetrasaccharides; the difference between the two groups regarded exclusively the type of alditol found at the reducing end, which was a glucosaminitol in the first case, or a N-acetylglucosaminitol in the other. Products were fully characterized by 2D NMR spectroscopy. The azido moieties installed on these oligosaccharides can be further exploited in Cu(I) catalyzed azido-alkyne cycloaddition reactions. PMID:22840011

  14. Cobalt azide complexes with a tris(carbene)borate ligand scaffold.

    Science.gov (United States)

    Scepaniak, Jeremiah J; Margarit, Charles G; Bontchev, Ranko P; Smith, Jeremy M

    2013-09-01

    The four-coordinate Co(II) complex, (azido-κN)[1,1,',1''-(phenylboranetriyl)tris(3-tert-butyl-1H-imidazol-2-ylidene)]cobalt(II), [Co(C27H38BN6)(N3)], (1), denoted PhB(t-BuIm)3CoN3, was prepared by the reaction of the corresponding chloride complex with NaN3. One-electron oxidation results in the isolation of the five-coordinate Co(III) complex, bis(azido-κN)[1,1,',1''-(phenylboranetriyl)tris(3-tert-butyl-1H-imidazol-2-ylidene)]cobalt(III), [Co(C27H38BN6)(N3)2], (2), denoted PhB(t-BuIm)3Co(N3)2. Attempts to prepare cobalt nitrides by thermolysis or photolysis of these complexes were unsuccessful. PMID:24005501

  15. Sulfonyl azide-mediated norbornene aziridination for orthogonal peptide and protein labeling

    Czech Academy of Sciences Publication Activity Database

    Gattner, M. J.; Ehrlich, M.; Vrábel, Milan

    2014-01-01

    Roč. 50, č. 83 (2014), s. 12568-12571. ISSN 1359-7345 Institutional support: RVO:61388963 Keywords : Diels-Adler reactions * transfer RNA synthetase * free click chemistry Subject RIV: CC - Organic Chemistry Impact factor: 6.834, year: 2014

  16. Photo-activation of d(0) niobium imido azides: en route to nitrido complexes.

    Science.gov (United States)

    Camp, Clément; Grant, Lauren N; Bergman, Robert G; Arnold, John

    2016-04-12

    We report the synthesis and photo-reactivity of d(0) niobium imido azido complexes supported by β-diketiminate ligands, which leads to the unprecedented formation of nitrides through a photo-assisted intramolecular rearrangement. This provides a new entry to metal nitrides that does not require low-valent metal centers and is a rare example in which the metal-imido moiety in group 5 complexes participates in reactivity. PMID:27033145

  17. Ammonium azide: A commented example of an Ab initio structure (Re-)determination from X-Ray powder diffraction

    OpenAIRE

    Helio Amorim Salim de; M. Amaral Jr. Rothier do; Philip Pattison; Isabel Ludka Pereira; Julio Cesar Mendes

    2002-01-01

    La estructura de la azida de amonio (NH4 )N3; fue redeterminada; medianteab-initioa partir de los datos de difracción de rayos; X empleando eadiación de sincrotrón. El compuesto cristaliza en el; grupo espacial Pmna (no.53) con a= 8.937(1) Å, b= 3.8070(5) Å, c; = 8.664(1) Å, V = 294.79(7) Å3; Z= 4. Fue posible localizar y refinar; las coordenadas de hidrógeno, en dos aproximaciones diferentes, y; establecer las uniones de hidrógeno. Los parámetros finales de la; estruc...

  18. Composition dependence of magnetic relaxation for CoNi chain-based compounds with mixed double azide-tetrazolate bridges.

    Science.gov (United States)

    Cheng, Min; Ding, You-Song; Gao, En-Qing; Zhang, Zhicheng; Jia, Qin-Xiang

    2016-05-10

    Seven isomorphous 2D CoNi (0 ≤ x ≤ 1) compounds based on ferromagnetic chains with mixed double [(μ-EO-N3)(μ-N-N-tetrazolate)] (EO = end-on) were synthesized and then structurally and magnetically characterized. They are formulated as [CoNi(L)(N3)(H2O)]·H2O (), (x = 1 (), 0.86 (), 0.74 (), 0.39 (), 0.14 (), 0.10 (), 0 (); L = 3-(5-tetrazole)-N-oxide-pyridine). Magnetic studies revealed that the homo-metallic compounds ( and ) behave as metamagnets, while the hetero-metallic compounds () show interesting composition-dependent slow relaxation due to the synergy effect of Co(II) and Ni(II) ions. PMID:27071813

  19. A new cube-based dodecanuclear cobalt(ii) cluster with azide and tetrazolate ligands exhibiting ferromagnetic ordering.

    Science.gov (United States)

    Zhang, Xiu-Mei; Li, Peng; Gao, Wei; Liu, Jie-Ping; Gao, En-Qing

    2015-08-14

    A new cubane-based Co(ii) compound, [Co(12)(5-PT)(6)(CO(3))(N(3))2(O)(4)(CH(3)O)(6)(H(2)O)(18)] (1) (5-HPT = 5-phenyl-1H-tetrazole), was synthesized by reaction of 5-HPT, CoCl(2)·6H(2)O and NaN(3) in a methanol solution. In 1, a Co(12) cluster based on three identical Co(4)O(2)(ON)(2) cubane units bridged by a μ(6)-carbonate ligand is linked by π-π stacking interactions between phenylene groups, forming a 3D supramolecular structure. Magnetic investigations indicate that compound 1 exhibits long-range ferromagnetic ordering at about 9 K. The cube-based Co(12) clusters with μ(6)-CO(3)(2-) bridges are unprecedented. PMID:26136165

  20. New pH-tunable vlock copolymer nanoparticles via controlled radical polymerization and azide-bintrile click chemistry

    Czech Academy of Sciences Publication Activity Database

    Jäger, Alessandro; Gromadzki, Daniel; Štěpánek, Petr

    Praha : Institute of Macromolecular Chemistry , 2009. s. 74. ISBN 978-80-85009-59-0. [Prague Meetings on Macromolecules /73./ New Frontiers in Macromolecular Science: From Macromolecular Concepts of Living Matter to Polymers for Better Quality of Life. 05.07.2009-09.07.2009, Prague] R&D Projects: GA ČR GA202/09/2078 Institutional research plan: CEZ:AV0Z40500505 Keywords : photoelectrical properties * solar energy Subject RIV: CD - Macromolecular Chemistry

  1. Continuous metal scavenging and coupling to one-pot copper-catalyzed azide-alkyne cycloaddition click reaction in flow

    NARCIS (Netherlands)

    Vural - Gursel, Dr. Iris; Aldiansyah, Ferry; Wang, Qi; Noël, Timothy; Hessel, Volker

    2015-01-01

    Increasing usage of catalytic chemistry calls for efficient removal of metal traces. This paper describes the development and optimization of a scavenger-based extraction in flow to remove metal catalysts. It enables liquid-liquid extraction with slug flow and phase separation with a porous fluoropo

  2. Solvent Composition Directing Click-Functionalization at the Surface or in the Bulk of Azide-Modified PEDOT

    DEFF Research Database (Denmark)

    Lind, Johan Ulrik; Hansen, Thomas Steen; Daugaard, Anders Egede;

    2011-01-01

    Thin films of the conducting polymer poly(3,4-(1-azidomethylethylene)dioxythiophene) tosylate (PEDOT−N3) can be functionalized by reaction with alkynated reagents in aqueous solutions. Reaction in pure water resulted in surface specific modification of PEDOT−N3 films, whereas both surface and bulk...... studies showed increasing film thickness with increasing DMSO content, with the measured thickness in pure DMSO being >250% of the thickness in pure water. A similar, but less pronounced, behavior was observed for unmodified poly(3,4-ethylenedioxythiophene) tosylate (PEDOT). High-density grafting of a...

  3. Two coordination polymers based on semicarbazone Schiff base and azide: synthesis, crystal structure, electrochemistry, magnetic properties and biological activity

    Czech Academy of Sciences Publication Activity Database

    Shaabani, B.; Khandar, A.A.; Dušek, Michal; Pojarová, Michaela; Mahmoudi, F.; Feher, A.; Kajňaková, M.

    2013-01-01

    Roč. 66, č. 5 (2013), s. 748-762. ISSN 0095-8972 Grant ostatní: AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : Schiff bases * semicarbazone * coordination polymer * structure analyses Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.224, year: 2013

  4. Non-Catalyzed Click Reactions of ADIBO Derivatives with 5-Methyluridine Azides and Conformational Study of the Resulting Triazoles

    Czech Academy of Sciences Publication Activity Database

    Smyslová, P.; Popa, I.; Lyčka, A.; Tejral, Gracian; Havlač, J.

    2015-01-01

    Roč. 10, č. 2 (2015), e0144613. E-ISSN 1932-6203 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:68378041 Keywords : copper-free click * alkyne cycloaddition * chemistry Subject RIV: CC - Organic Chemistry Impact factor: 3.234, year: 2014

  5. Reactivity studies of eta sup (6)-p-cymene ruthenium(II) carboxylato complexes towards azide some neutral ligands

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kollipara, M.R.

    complexes with NaN sub (3) yielded azido complex [{(eta sup (6)-p-cymene)Ru(mu-N sub (3))Cl} sub (2)] whereas halide scavengers such as silver acetate, silvertrifluroacetate leads to the substitution of chlorine to give neutral complexes of formulation...

  6. Citrus Peel Additives for One-Pot Triazole Formation by Decarboxylation, Nucleophilic Substitution, and Azide-Alkyne Cycloaddition Reactions

    Science.gov (United States)

    Mendes, Desiree E.; Schoffstall, Allen M.

    2011-01-01

    This undergraduate organic laboratory experiment consists of three different reactions occurring in the same flask: a cycloaddition reaction, preceded by decarboxylation and nucleophilic substitution reactions. The decarboxylation and cycloaddition reactions occur using identical Cu(I) catalyst and conditions. Orange, lemon, and other citrus fruit…

  7. Efficient Synthesis of 1,5-disubstituted-1H-tetrazoles by an Ugi-azide Process

    Directory of Open Access Journals (Sweden)

    Luis Edilberto Cárdenas-Galindo

    2013-01-01

    Full Text Available Fue preparada una serie de dieciocho nuevos tetrazoles-1H-1,5-disubstituidos con rendimientos de moderados a buenos utilizando una reacción Ugi-azida como proceso clave bajo condiciones suaves. Los tetrazoles son sistemas heterocíclicos presentes en diversos productos sintéticos con actividad biológica privilegiada. En este trabajo describimos la síntesis de nuevos compuestos con el núcleo de tetrazol, los cuales podrían presentar actividad biológica.

  8. Tandem deprotonation/azide-tetrazole tautomerization of 4,6-diazido-N-nitro-1,3,5-triazin-2-amine in dimethylsulfoxide solutions: a theoretical study.

    Science.gov (United States)

    Chapyshev, S V; Ushakov, E N

    2015-07-14

    4,6-Diazido-N-nitro-1,3,5-triazin-2-amine (2) is a new promising high-energy organic compound that isomerizes in dimethylsulfoxide (DMSO) solutions to form unknown products with interesting 13C and 15N NMR spectroscopic characteristics. To identify these products, the relative energies and the 13C and 15N chemical shifts were calculated for various prototropic and valence isomers of 2. It was found that this diazide in DMSO solutions exists in equilibrium with the deprotonated form of 5-azido-N-nitrotetrazolo[1,5-a][1,3,5]triazin-7-amine (8). The anion 8 is also observed in DMSO solutions of energetic salts derived from 2 and guanidines or 4H-1,2,4-triazol-4-amines. The tandem transformations of 2 in DMSO solutions found may be of interest from both theoretical and practical points of view, for instance, in the synthesis of new energetic materials, using the reactions of anion 8 with various electrophilic agents. PMID:26073044

  9. Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

    ))Ru(L sub(2)){N sub(3)C sub(2)(CO sub(2)R) sub(2))) (where; R = Me, 5; Et, 6). The compounds were characterized by spectroscopy and the structures of representative compounds 4 and 6 have been determined by single crystal X-ray diffraction. The two...

  10. In situ construction of three anion-dependent cu(i) coordination networks as promising heterogeneous catalysts for azide-alkyne "click" reactions.

    Science.gov (United States)

    Xu, Zhenghu; Han, Lu Lu; Zhuang, Gui Lin; Bai, Jing; Sun, Di

    2015-05-18

    Three Cu(I) coordination networks, namely, {[Cu2(bpz)2(CN)X]·CH3CN}n, (X = Cl, 1; I, 3), {[Cu6(bpz)6(CH3CN)3(CN)3Br]·2OH·14CH3CN}n, (2, bpz = 3,3',5,5'-tetramethyl-4,4'-bipyrazole), were prepared by using solvothermal method. The cyanide ligands in these networks were generated in situ by cleavage of C-C bond of MeCN under solvothermal condition. The structures of these networks are dependent on halogen anions. Complex 1 is a ladderlike structure with μ2-CN(-) as rung and μ2-bpz as armrest. The Cl(-) in 1 is at terminal position but does not extend the one-dimensional (1D) ladder to higher dimensionalities. Complex 2 is a three-dimensional (3D) framework comprised of novel planar [Cu3Br] triangle and single Cu nodes, which are extended by μ2-bpz and μ2-CN(-) to form a novel (3,9)-connected gfy network. Density functional theory calculations showed that single-electron delocalization of Br atom induces the plane structure of [Cu3Br]. Complex 3 also possesses a similar ladderlike subunit as in 1, but the I(-) acts as bidentate bridge to extend the ladder to 3D framework with a four-connected sra topology. The three networks show notable catalytic activity on the click reaction. The compared catalytic results demonstrate that complex 2 possesses the best catalysis performance among three complexes, which is ascribed to the largest solvent-accessible void (porosity: 2 (29.4%) > 1 (25.7%) > 3 (17.6%)) and the more Cu(I) active sites in 2. The present combined structure-property studies provide not only a new synthetic route to obtain a new kind of catalyst for click reaction but also the new insights on catalyst structure-function relationships. PMID:25941881

  11. INDUCTION OF POLYPLOID MUTANT IN LINUM USITATISSIMUM L. BY THE COMBINED ACTION OF 5 KR GAMMA RAYS + 0.10% SODIUM AZIDE.

    OpenAIRE

    Ansari, M. Y. K.; ALKA

    2013-01-01

    So far colchicine has been used to induce polyploidy in various plants. But herethe effect of the combined treatment of 5 kR ã-Rays and 0.10% SA on polyploidy inductionhas been obtained in Linum usitatissimum. Out of 300 plants, 9 plants were tetraploidshowing significant superiority over control plants, such as increased height, thicknessof stem, leaf size, capsule and flower size and yield. Chromatin transfer due to cytomixisand/ or endomitosis due to dissolution of spindle fibre may be res...

  12. INDUCTION OF POLYPLOID MUTANT IN LINUM USITATISSIMUM L. BY THE COMBINED ACTION OF 5 KR GAMMA RAYS + 0.10% SODIUM AZIDE.

    Directory of Open Access Journals (Sweden)

    M.Y.K. ANSARI

    2013-05-01

    Full Text Available So far colchicine has been used to induce polyploidy in various plants. But herethe effect of the combined treatment of 5 kR ã-Rays and 0.10% SA on polyploidy inductionhas been obtained in Linum usitatissimum. Out of 300 plants, 9 plants were tetraploidshowing significant superiority over control plants, such as increased height, thicknessof stem, leaf size, capsule and flower size and yield. Chromatin transfer due to cytomixisand/ or endomitosis due to dissolution of spindle fibre may be responsible for doubling ofchromosomes. Tetraploid plants of Linum having 2n = 4x = 60 chromosomes wereobtained in M2 and M3 generations. This type of mutation breeding makes extensive useof deviations from the normal characters to improve the characterstics of crops by plantbreeders.

  13. Revisiting the mechanism of the mono nuclear copper-catalyzed cycloaddition of azide and alkynes (CuAAC) by the topology of ....

    OpenAIRE

    Calvo-Losada, Saturnino; Pino-González, María Soledad; Quirante, José Joaquín

    2013-01-01

    Se analiza el mecanismo de la reacción de cicloadición, catalizada por Cu(I), de azidas a alquinos (CuAAC), haciendo uso de métodos DFT y de herramientas de análisis de la densidad electrónica basadas en la topología de su laplaciana. Comunicación presentada y aceptada en el CHITEL2013, XXXIX International Conference THEORETICAL CHEMISTS OF LATIN EXPRESSION (XXXIX Congreso Internacional de Químicos de Expresión Latina).

  14. Interactions of DNA with a new platinum(IV) azide dipyridine complex activated by UVA and visible light: Relationship to toxicity in tumor cells

    Czech Academy of Sciences Publication Activity Database

    Prachařová, J.; Zerzánková, Lenka; Štěpánková, Jana; Nováková, Olga; Farrer, N.J.; Sadler, P.J.; Brabec, Viktor; Kašpárková, Jana

    2012-01-01

    Roč. 25, č. 5 (2012), s. 1099-1111. ISSN 0893-228X R&D Projects: GA ČR(CZ) GAP301/10/0598; GA ČR(CZ) GD301/09/H004 Institutional research plan: CEZ:AV0Z50040702 Keywords : antitumor platinum * photoactivation * DNA Subject RIV: BO - Biophysics Impact factor: 3.667, year: 2012

  15. Magnetic Field Effect on Chemical Compositions of Magnetic Aerosol Particles Synthesized Photochemically from a Gaseous Mixture of Iron Pentacarbonyl and Trimethylsilyl Azide

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Okano, Y.; Šubrt, Jan

    2013-01-01

    Roč. 47, č. 11 (2013), s. 1188-1195. ISSN 0278-6826 Institutional support: RVO:61388980 Keywords : containing ultrafine particles * gas-phase synthesis * carbon-disulfide Subject RIV: CA - Inorganic Chemistry Impact factor: 3.155, year: 2013

  16. Synthesis of novel triazoles bearing 1,2,4-oxadiazole and phenylsulfonyl groups by 1,3-dipolar cycloaddition of some organic azides and their biological activities

    OpenAIRE

    DÜRÜST, Yaşar; KARAKUŞ, Hamza; YAVUZ, Muhsine Zeynep; GEPDİREMEN, Ali Akçahan

    2014-01-01

    1,3-Dipolar cycloaddition of 5-azidomethyl-3-p-substituted phenyl-1,2,4-oxadiazoles to phenyl vinyl sulfone and bismaleimide gives rise straightforwardly to 1-((3-(p-substituted) phenyl-1,2,4-oxadiazol-5-yl)methyl)-4-(phenylsul\\-fonyl)-4,5-dihydro-1H-1,2,3-triazoles and bisdihydropyrrolo[3,4-d][1,2,3]triazole-4,6(3aH,5H)-diones. The structures of the new cycloadducts were elucidated by means of IR, NMR (1H, 13C, 2D), mass spectra, and physical characteristics (mp and Rf values). In addition, ...

  17. Synthesis of DOTA-conjugated multimeric [Tyr3]octreotide peptides via a combination of Cu(I)-catalyzed "click" cycloaddition and thio acid/sulfonyl azide "sulfo-click" amidation and their in vivo evaluation.

    NARCIS (Netherlands)

    Yim, C.B.; Dijkgraaf, I.; Merkx, R.; Versluis, C.; Eek, A.; Mulder, G.E.; Rijkers, D.T.; Boerman, O.C.; Liskamp, R.M.

    2010-01-01

    Herein, we describe the design, synthesis, and biological evaluation of a series of DOTA-conjugated monomeric, dimeric, and tetrameric [Tyr(3)]octreotide-based analogues as a tool for tumor imaging and/or radionuclide therapy. These compounds were synthesized using a Cu(I)-catalyzed 1,3-dipolar cycl

  18. Experimental and Computational Studies of Binding of Dinitrogen, Nitriles, Azides, Diazoalkanes, Pyridine and Pyrazines to M(PR3)2(CO)3 (M=Mo, W; R=Me, iPr)

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, C.D.; Muckerman, J.; Achord, P.; Fujita, E.; Scott, B.; Fortman, G.C.; Temprado, M.; Cai, X.; Captain, B.; Isrow, D.; Weir, J.J.; McDonough, J.E.

    2009-08-17

    The enthalpies of binding of a number of N-donor ligands to the complex Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3} in toluene have been determined by solution calorimetry and equilibrium measurements. The measured binding enthalpies span a range of {approx}10 kcal mol{sup -1}: {Delta}H{sub binding} = -8.8 {+-} 1.2 (N{sub 2}-Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}); -10.3 {+-} 0.8 (N{sub 2}); -11.2 {+-} 0.4 (AdN{sub 3} (Ad = 1-adamantyl)); -13.8 {+-} 0.5 (N{sub 2}CHSiMe{sub 3}); -14.9 {+-} 0.9 (pyrazine = pz); -14.8 {+-} 0.6 (2,6-Me{sub 2}pz); -15.5 {+-} 1.8 (Me{sub 2}NCN); -16.6 {+-} 0.4 (CH{sub 3}CN); -17.0 {+-} 0.4 (pyridine); -17.5 {+-} 0.8 ([4-CH{sub 3}pz][PF{sub 6}] (in tetrahydrofuran)); -17.6 {+-} 0.4 (C{sub 6}H{sub 5}CN); -18.6 {+-} 1.8 (N{sub 2}CHC(=O)OEt); and -19.3 {+-} 2.5 kcal mol{sup -1} (pz)Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}). The value for the isonitrile AdNC (-29.0 {+-} 0.3) is 12.3 kcal mol{sup -1} more exothermic than that of the nitrile AdCN (-16.7 {+-} 0.6 kcal mol{sup -1}). The enthalpies of binding of a range of arene nitrile ligands were also studied, and remarkably, most nitrile complexes were clustered within a 1 kcal mol{sup -1} range despite dramatic color changes and variation of v{sub CN}. Computed structural and spectroscopic parameters for the complexes Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}L are in good agreement with experimental data. Computed binding enthalpies for Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}L exhibit considerable scatter and are generally smaller compared to the experimental values, but relative agreement is reasonable. Computed enthalpies of binding using a larger basis set for Mo(PMe{sub 3}){sub 2}(CO){sub 3}L show a better fit to experimental data than that for Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}L using a smaller basis set. Crystal structures of Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(AdCN), W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(Me{sub 2}NCN), W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(2,6-F{sub 2}C{sub 6}H{sub 3}CN), W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(2,4,6-Me{sub 3}C{sub 6}H{sub 2}CN), W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(2,6-Me{sub 2}pz), W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(AdCN), Mo(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(AdNC), and W(P{sup i}Pr{sub 3}){sub 2}(CO){sub 3}(AdNC) are reported.

  19. Research Advances in Synthesis and Modification of Glycidyl Azide Polymer%聚叠氮缩水甘油醚的合成与改性研究进展

    Institute of Scientific and Technical Information of China (English)

    王旭朋; 罗运军; 郭凯; 吕勇

    2009-01-01

    聚叠氮缩水甘油醚(GAP)是国内外重点研究的含能粘合剂之一.该文综述了GAP的合成研究进展,重点介绍了高相对分子质量GAP、支化GAP和等规GAP的合成.针对GAP反应活性低的特点,介绍了GAP的多种端基改性方法.GAP的无规、嵌段共聚物改善了GAP粘合剂的性能,GAP与其他粘合剂的互穿及共混,为GAP在推进剂中的应用提供了广阔前景.引用文献37篇.

  20. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kaminsky, W.

    The arene ruthenium(II) azido compounds [{(p-cymene)Ru(N^O)N3}] have been prepared by the reaction of [{(p-cymene)Ru(mewN3)Cl}2] with the corresponding ligands. The ruthenium azido compounds [{(p...

  1. Regioselective [3+2] cycloaddition of chalcones with a sugar azide: easy access to 1-(5-deoxy-D-xylofuranos-5-yl)-4,5-disubstituted-1H-1,2,3-triazoles.

    Science.gov (United States)

    Singh, Nimisha; Pandey, S K; Tripathi, Rama P

    2010-08-16

    [3+2] Cycloaddition of 5-azido-5-deoxy-1,2-O-isopropylidene-alpha-d-xylofuranose with 1,3-diphenyl-prop-3-enones, followed by oxidation of the intermediate triazolines in a tandem manner, led to the regioselective formation of 4-benzoyl-1-(5-deoxy-1,2-O-isopropylidene-alpha-d-xylofuranos-5-yl)-5-phenyl-1H-1,2,3-triazoles in moderate to good yields. PMID:20579636

  2. Polymer End Group Modifications and Polymer Conjugations via " Click" Chemistry Employing Microreactor Technology

    OpenAIRE

    Vandenbergh, Joke; Tura, Tiago; Baeten, Evelien; Junkers, Thomas

    2014-01-01

    This study presents the development of microreactor protocols for the successful continuous flow end group modification of atom transfer radical polymerization precursor polymers into azide end-capped materials and the subsequent copper-catalyzed azide alkyne click reactions with alkyne polymers, in flow. By using a microreactor, the reaction speed of the azidation of poly(butyl acrylate), poly(methyl acrylate), and polystyrene can be accelerated from hours to seconds and full end group conve...

  3. The crystal structure of Cs5Eu(N3)8

    International Nuclear Information System (INIS)

    The crystal structure of pentacesium octaazidoeuropiate(III), Cs5Eu(N3)8, was determined by single crystal X-ray diffraction: orthorhombic, a = 16,811(4), b = 16,860(5), c = 16,964(3)A, space group Pbca, Z = 8, 2310 observed reflections, R = 0,048. Europium atoms are coordinated to eight azide groups, the coordination polyhedra have no azide groups in common. Four cesium atoms are surrounded by eigth, one by seven azide groups. The azide groups are symmetric with mean N - N-distances of 1,17(1)A. (Authors)

  4. Cu (I) catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC): Synthesis of 17α-[1-(substituted phenyl)-1,2,3-triazol-4-yl]-19-nor-testosterone-17β-yl acetates targeting progestational and antipro-liferative activities.

    Science.gov (United States)

    Mohamed, Z H; El-Koussi, Nawal A; Mahfouz, Nadia M; Youssef, Adel F; Abdel Jaleel, Gehad A; Shouman, Samia A

    2015-06-01

    The progestational potency and selectivity of synthetic steroidal agonists can be enhanced by even larger chemical moieties at 17α-position of the steroid backbones. Hereby a series 5a-c and 6a-c of novel 17α-[1-(substituted phenyl)-1,2,3-triazol-4-yl]-19-nortestosterone-17β-yl acetates were designed and synthesized using click chemistry approach searching progestogenic derivatives with potential anticancer activity. Compounds 5a,b and 6a,c have affected to different extents the three histopatho-logical parameters considered for evaluation of their progestational activity. The compounds 5a,b and 6a,c showed modifications in rat uterus at 35.7-34.8 nM levels with privileged endometrial thickening effect and least change of uterine weight relative to NEA at 52.9 nM level. Up to 40 mg/kg dose compounds 5b and 6c were non-toxic. Molecular docking of the ligands in PR showed in the majority of cases a conformational fitting into the active site different from that of the reference steroid NEA. Compound 6b revealed about 46.4% growth inhibition of CNS cancer SNB-75 cell line, 56% growth inhibition of renal cancer A498 cell line and 56.7% growth inhibition of prostate cancer PC-3 cell line which was mediated by cell cycle arrest. Drugability of the screened compounds showed tolerated results after being challenged to diverse physicochemical parameters. PMID:25942354

  5. Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn2(C8H9N2O3S)2·(N3)2·(H2O)2]2·2H2O

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi-Min; LI Jia-Ming; XIE Fu-Qing; WANG Yan-Fei

    2006-01-01

    The title complex [Zn2L2(N3)2(H2O)2]·2H2O (L = N-(2-pyridylmethylidene) taurine)has been synthesized in a methanol-water solution. The crystal belongs to monoclinic, space group P21/c with a = 15.8064(10), b = 10.5015(5), c = 17.3193(11) (A), β = 111.314(2)°, V = 2678.2(3) (A)3, C16H26N10O10S2Zn2, Mr = 713.33, Z = 4, Dc = 1.769 g/cm3, μ = 2.017 mm-1 and F(000) =1456. The asymmetric unit consists of two half-molecules of the complex and two water molecules.Four N and two O atoms form the coordination environment of each Zn atom, resulting in a distorted octahedral configuration. The two halves of each independent dimer are related by a crystallographic inversion centre, which lies at the centre of the ring formed by two Zn atoms and the coordinating the ac plane.

  6. End Group-Functionalization and Synthesis of Block-Copolythiophenes by Modified Nickel Initiators

    OpenAIRE

    Smeets, Alfons; Willot, Pieter; De Winter, Julien; Gerbaux, Pascal; Verbiest, Thierry; Koeckelberghs, Guy

    2011-01-01

    Polythiophenes with alcohol, tosylate, azide, ethynylene, carboxylic acid, and amine end groups were prepared by a combination of functionalized nickel initiators and postpolymerization reactions. The azide and ethynylene polymers were subsequently used in a click reaction to produce a conjugated block copolymer. Finally, a conjugated triblock-copolymer was synthesized by means of a chain growth polymerization initiated by a binuclear nickel initiator.

  7. Analytical use of zide ion. Chemical equilibrium studies and correlates in U(VI)/N3 and Co(III)/N3 systems

    International Nuclear Information System (INIS)

    A monographic study about the azide ion and its structure, as well as, references about the uranyl ion in aqueous medium, and its possible hydrolysis products are shown. Spectral studies of the U(VI), Fe (III) and Cu(II) systems, in azide medium are analyzed. (M.J.C.)

  8. Utilization of metabolic inhibitors for shifting product formation from xylitol to ethanol in pentose fermentations using Candida tropicalis

    Energy Technology Data Exchange (ETDEWEB)

    Lohmeier-Vogel, E.; Hahn-Haegerdal, B.

    1985-02-01

    Xylose, glucose and xylose/glucose mixtures were fermented with Candida tropicalis ATCC 32113 under aerobic, oxygen limited and anaerobic conditions. Ethanol yields were highest under oxygen limited conditions with xylose and xylose/glucose. Anaerobic conditions were best for glucose fermentations. The effect of four metabolic inhibitors (azide, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), oligomycin A and valinomycin-K/sup +/) were then studied under oxygen limited conditions. Only azide had a significant influence on ethanol production. At 2x10/sup -4/ M concentrations, ethanol yield increased up to two times and xylitol levels were repressed by 90% for xylose and glucose/xylose fermentations. 4.2x10/sup -3/ M azide gave highest ethanol yields in glucose fermentations. At this concentration of azide, however, cell growth was inhibited, which seemed to prevent ethanol production in xylose fermentations. The effect of azide is discussed in terms of 'fine-tuning' the respiratory activity necessary for metabolism.

  9. Ligand Binding to Chlorite Dismutase from Magnetospirillum sp.

    Science.gov (United States)

    De Schutter, Amy; Correia, Hugo D; Freire, Diana M; Rivas, María G; Rizzi, Alberto; Santos-Silva, Teresa; González, Pablo J; Van Doorslaer, Sabine

    2015-10-29

    Chlorite dismutase (Cld) catalyzes the reduction of chlorite to chloride and dioxygen. Here, the ligand binding to Cld of Magnetospirillum sp. (MaCld) is investigated with X-ray crystallography and electron paramagnetic resonance (EPR). EPR reveals a large heterogeneity in the structure of wild-type MaCld, showing a variety of low- and high-spin ferric heme forms. Addition of an axial ligand, such as azide or imidazole, removes this heterogeneity almost entirely. This is in line with the two high resolution crystal structures of MaCld obtained in the presence of azide and thiocyanate that show the coordination of the ligands to the heme iron. The crystal structure of the MaCld-azide complex reveals a single well-defined orientation of the azide molecule in the heme pocket. EPR shows, however, a pH-dependent heme structure, probably due to acid-base transitions of the surrounding amino-acid residues stabilizing azide. For the azide and imidazole complex of MaCld, the hyperfine and nuclear quadrupole interactions with the close-by (14)N and (1)H nuclei are determined using pulsed EPR. These values are compared to the corresponding data for the low-spin forms observed in the ferric wild-type MaCld and to existing EPR data on azide and imidazole complexes of other heme proteins. PMID:26287794

  10. Synthesis of 5-phenyltetrazole and its N-methyl Derivatives in a Microreactor

    OpenAIRE

    E. A. Popova; Abiev, R. Sh.; Lappalainen, L. A.; Svetlov, S. D.; Andreeva, T. V.; Trifonov, R. E.; Ostrovskii, V. A.

    2014-01-01

    Azidation of benzonitrile with dimethylammonium azide yielding 5-phenyltetrazole dimethylammonium salt was performed under microreactor conditions. The kinetics of azidation of benzonitrile in DMF was investigated at the range 80–95 °С. The reaction rate constants were determined:kII·104(L mol–1 s–1): 0.79, 0.97, 1.19, 1.51, at 80, 85, 90, and 95 °С, respectively. It was found that the reaction rate constants obtained in a microreactor are comparable to ones for a batch-type reactor. The ther...

  11. SYNTHESIS AND MICROBIAL EVALUATION OF NOVEL TETRAZOLO-TRIAZOLE DERIVATIVES SYNTHESIS und mikrobielle Evaluierung neuartiger Tetrazolo-triazol DERIVATE

    Directory of Open Access Journals (Sweden)

    Vijay V Dabholkar, Navnath Shinde, Abhishekh Karekar and Prem Naik

    2013-01-01

    Full Text Available 5-(4'-Bromomethyl-1, 1'-biphenyl-2-yl -1H-tetrazole (1 was converted into its azide derivative using sodium azide (2, which on further treatment with malonitrile, diethyl malonate, ethyl acetoacetate and isopropyl acetoacetate to yielded the respective tetrazole-triazole derivatives. The structures of the synthesized compounds were confirmed by Physico-chemical test and spectral techniques, representative samples were screened for their antimicrobial activity against gram positive and gram negative bacteria. Key words: Tetrazoles, Triazoles, Triphenyl phosphine, azides

  12. Star-Shaped Polyacrylates: Highly Functionalized Architectures via CuAAC Click Conjugation.

    Science.gov (United States)

    Lammens, Mieke; Fournier, David; Fijten, Martin W M; Hoogenboom, Richard; Prez, Filip Du

    2009-12-01

    Well-defined functional star-shaped polymer structures with up to 29 arms have been successfully synthesized by the combination of atom transfer radical polymerization (ATRP) and click chemistry. First, azide end-functionalized poly(isobornyl acrylate) (PiBA) star-shaped polymers were prepared by successive ATRP and bromine substitution. Subsequently, alkyne end-functionalized molecules and polymers were introduced onto the star-shaped PiBA bearing pendant azide moieties by copper-catalyzed azide-alkyne cycloaddition (CuAAC). The possibilities and limits for the CuAAC on such highly branched polyacrylates are described. PMID:21638494

  13. Regioselective Preparation of 1,2,3-Triazoles for Bioactive Studies Based on Marine Bioprospecting

    OpenAIRE

    Hansen, Ole Kudsk

    2015-01-01

    The azides 1d and 1c were prepared using literature procedures. The azides serve as starting materials in copper- and ruthenium-catalyzed 1,3-dipolar dipolar cycloadditions to N-protected alkynes 2a and 2b, to afford 1,4-disubstituted 1H-1,2,3-triazoles and 1,5-disubstituted 1H-1,2,3-triazoles, respectively. A recently published procedure for preparing 1c in one step from the aldehyde 5a was tested, but no product was obtained. The azide was synthesized by a more traditional approach, via the...

  14. catena-Poly[[(1,10-phenanthroline-κ2 N,N′)lead(II)]-μ-azido-κ2 N 1:N 3-μ-nitrito-κ3 O,O′:O′-[(1,10-phenanthroline-κ2 N,N′)lead(II)]-di-μ-azido-κ4 N 1:N 1

    OpenAIRE

    Gholamhossein Mohammadnezhad; Ali Reza Ghanbarpour; Amini, Mostafa M.; Seik Weng Ng

    2010-01-01

    The title coordination polymer, [Pb2(N3)3(NO2)(C12H8N2)2]n, has as the repeat unit a centrosymmetric dinuclear molecule having azide and nitrite groups that bridge adjacent heterocycle-coordinated metal centers. One of the azide group uses its terminal ends to bridge whereas the nitrite group chelates to one metal atom and uses one of its O atoms to bridge. The azide and nitrite groups are disordered with respect to each other in a 1:1 ratio. Adjacent dinuclear molecules are further bridged b...

  15. Microwave-Promoted Rapid Synthesis of 1-Aryl-1, 2, 3-Triazoles

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Aryl azides and a-keto phosphorus ylides were reacted within 4~10 minutes with silica gel support, under microwave irridiation to afford corresponding l-aryl-l, 2, 3-triazoles in moderate to good yields.

  16. A versatile toolbox for posttranscriptional chemical labeling and imaging of RNA

    Science.gov (United States)

    Sawant, Anupam A.; Tanpure, Arun A.; Mukherjee, Progya P.; Athavale, Soumitra; Kelkar, Ashwin; Galande, Sanjeev; Srivatsan, Seergazhi G.

    2016-01-01

    Cellular RNA labeling strategies based on bioorthogonal chemical reactions are much less developed in comparison to glycan, protein and DNA due to its inherent instability and lack of effective methods to introduce bioorthogonal reactive functionalities (e.g. azide) into RNA. Here we report the development of a simple and modular posttranscriptional chemical labeling and imaging technique for RNA by using a novel toolbox comprised of azide-modified UTP analogs. These analogs facilitate the enzymatic incorporation of azide groups into RNA, which can be posttranscriptionally labeled with a variety of probes by click and Staudinger reactions. Importantly, we show for the first time the specific incorporation of azide groups into cellular RNA by endogenous RNA polymerases, which enabled the imaging of newly transcribing RNA in fixed and in live cells by click reactions. This labeling method is practical and provides a new platform to study RNA in vitro and in cells. PMID:26384420

  17. “Clickable” polymer nanoparticles: a modular scaffold for surface functionalization

    OpenAIRE

    Krovi, Sai Archana; Smith, DeeDee; Nguyen, SonBinh T.

    2010-01-01

    The versatility of copper-catalyzed alkyne-azide coupling (CuAAC) in functionalizing drug-loaded polymer nanoparticles is demonstrated via the modification of surfaces of acetylene-functionalized PNPs with folate, biotin, and gold nanoparticles.

  18. Spatially Selective Functionalization of Conducting Polymers by "Electroclick" Chemistry

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Daugaard, Anders Egede; Hvilsted, Søren;

    2009-01-01

    Conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization by "click chemistry" with high spatial resolution. Interdigitated microelectrodes prepared from an azide-containing conducting polymer are selectively functionalized in sequence...

  19. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede;

    An azide substituted 3,4-ethylenedioxythiophene monomer is polymerised to yield a PEDOT like polymer with available azide groups (Figure 1). The azide groups enable post polymerization functionalization of the conducting polymer using a 1,3 dipolar cycloaddition reaction – also denoted “click...... chemistry”. This facilitates the addition of compounds that can otherwise not withstand the polymerization conditions. Several biological active molecules have been attached and tested on the films. Furthermore conducting polymer microelectrodes can electrochemically generate the catalyst required for their...... own functionalization with high spatial resolution. Interdigitated microelectrodes prepared from the azide-containing conducting polymer were selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. “Electro-click” on conducting polymer films...

  20. catena-Poly[[(1,10-phenanthroline-κ2N,N′lead(II]-μ-azido-κ2N1:N3-μ-nitrito-κ3O,O′:O′-[(1,10-phenanthroline-κ2N,N′lead(II]-di-μ-azido-κ4N1:N1

    Directory of Open Access Journals (Sweden)

    Gholamhossein Mohammadnezhad

    2010-07-01

    Full Text Available The title coordination polymer, [Pb2(N33(NO2(C12H8N22]n, has as the repeat unit a centrosymmetric dinuclear molecule having azide and nitrite groups that bridge adjacent heterocycle-coordinated metal centers. One of the azide group uses its terminal ends to bridge whereas the nitrite group chelates to one metal atom and uses one of its O atoms to bridge. The azide and nitrite groups are disordered with respect to each other in a 1:1 ratio. Adjacent dinuclear molecules are further bridged by the other two azide groups, generating a linear chain motif parallel to [010]. Half of the Pb atoms show a Ψ-dodecahedral coordination and the other half show a Ψ-pentagonal-bipyramidal coordination.

  1. Molecular and Crystal Structures of Three Berberine Derivatives

    OpenAIRE

    Jiří Dostál; Zdirad Žák; Marek NeÄÂas; Milan PotáÄÂek; Stanislav Man

    2001-01-01

    Berberine azide, berberine thiocyanate, and 8-cyano-8H-berberine were prepared from berberine chloride, a quaternary protoberberine alkaloid. The molecular and crystal structures of all compounds are reported and discussed.

  2. Molecular and Crystal Structures of Three Berberine Derivatives

    Directory of Open Access Journals (Sweden)

    Jiří Dostál

    2001-04-01

    Full Text Available Berberine azide, berberine thiocyanate, and 8-cyano-8H-berberine were prepared from berberine chloride, a quaternary protoberberine alkaloid. The molecular and crystal structures of all compounds are reported and discussed.

  3. Syntheses and Crystal Structures of Two Manganese(H) Coordination Polymers Having 3,4-Diimidazol-Thiophene Ligand Coordinated by Azide and Thiocyanate Counterions%两个含有叠氮根和硫氰根配位单元的3,4-双咪唑噻吩锰(Ⅱ)配位聚合物的合成与晶体结构

    Institute of Scientific and Technical Information of China (English)

    金超; 王银歌; 钱惠芬; 黄伟

    2014-01-01

    制备了2个含有叠氮根和硫氰根配位单元的3,4-双咪唑噻吩(L)的锰(Ⅱ)配位聚合物[Mn(L)(N3)2(H2O)]n(1)和[Mn(L)2(SCN3)2]n(2)并报道了它们的晶体结构.化合物1和2是通过3,4-双咪唑噻吩与四水醋酸锰反应,同时分别引入过量的线性三原子阴离子(N3-和SCN-)以取代醋酸根作为抗衡离子制备而得.单晶结构分析表明1和2具有相同的无限二维链状空间结构,但是由不同的44元的[Mn6(L)4(2N3)2]和36元的[Mn4]大环单元结构组成.此外,配位聚合物1中的叠氮根分别采用端基单齿和桥联双齿的配位方式,而配位聚合物2中的硫氰根仅以端基氮原子与Mn(Ⅱ)离子配位.

  4. One-Step Derivatization of Reducing Oligosaccharides for Rapid and Live-Cell-Compatible Chelation-Assisted CuAAC Conjugation.

    Science.gov (United States)

    Machida, Takuya; Winssinger, Nicolas

    2016-05-01

    We report a new reagent for the functionalization of unprotected oligosaccharides with a picolyl azide group at the anomeric position for chelation-assisted copper-catalyzed alkyne-azide cycloaddition (CuAAC) glycoconjugation. We show that oligosaccharides functionalized with this moiety react with an apparent second-order rate constant of 193 m(-1)  s(-1) and can be used to functionalize biomolecules bearing alkyne moieties introduced through metabolic labeling, including in live cells. PMID:26852736

  5. The Growing Impact of Bioorthogonal Click Chemistry on the Development of Radiopharmaceuticals

    OpenAIRE

    Zeng, Dexing; Zeglis, Brian M; Lewis, Jason S.; Anderson, Carolyn J.

    2013-01-01

    Click chemistry has become a ubiquitous chemical tool with applications in nearly all areas of modern chemistry, including drug discovery, bioconjugation, and nanoscience. Radiochemistry is no exception, as the canonical Cu(I)-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, inverse electron demand Diels-Alder reaction, and other types of bioorthogonal click ligations have had a significant impact on the synthesis and development of radiopharmaceuticals. This ...

  6. Direct synthesis of 1,5-disubstituted-4-magnesio-1,2,3-triazoles, revisited.

    Science.gov (United States)

    Krasiński, Antoni; Fokin, Valery V; Sharpless, K Barry

    2004-04-15

    After revisiting earlier works reporting the regioselective synthesis of 1,5-disubstituted-1,2,3-triazoles via the addition of bromomagnesium acetylides to azides, much improved yields of the products were obtained for a wide array of azides and alkynes. The intermediates of that reaction can be trapped with different electrophiles to regioselectively form 1,4,5-trisubstituted 1,2,3-triazoles. [reaction: see text] PMID:15070306

  7. Liquid-Phase Epitaxial Growth of Highly Oriented and Crystalline MOF Thin Films: Post-Synthetic Modification and Different Applications

    OpenAIRE

    Wang, Zhengbang

    2015-01-01

    The studies for this PhD thesis showed the preparation, characterization and application of new-type surface-mounted metal-organic frameworks (SURMOFs). The aims were to: (1) heteroepitaxially grow MOF-on-MOF multilayer systems with huge lattice mismatch; (2) modify azide-based SURMOFs using alkyne-azide click chemistry; (3) chemically pattern SURMOFs using postsynthetic modification (PSM); (4) engineer UHM-3 SURMOFs with quantitative Cu(I) defects using postsynthetic thermal treatment.

  8. Reactivity of Biarylazacyclooctynones in Copper-Free Click Chemistry

    OpenAIRE

    Gordon, Chelsea G.; Mackey, Joel L.; Jewett, John C.; Sletten, Ellen M; Houk, K. N.; Bertozzi, Carolyn R.

    2012-01-01

    The 1,3-dipolar cycloaddition of cyclooctynes with azides, also called “copper-free click chemistry”, is a bioorthogonal reaction with widespread applications in biological discovery. The kinetics of this reaction are of paramount importance for studies of dynamic processes, particularly in living subjects. Here we performed a systematic analysis of the effects of strain and electronics on the reactivity of cyclooctynes with azides through both experimental measurements and computational stud...

  9. "Clickable" LNA/DNA probes for fluorescence sensing of nucleic acids and autoimmune antibodies

    DEFF Research Database (Denmark)

    Jørgensen, Anna S; Gupta, Pankaj; Wengel, Jesper; Astakhova, I Kira

    2013-01-01

    Herein we describe fluorescent oligonucleotides prepared by click chemistry between novel alkyne-modified locked nucleic acid (LNA) strands and a series of fluorescent azides for homogeneous (all-in-solution) detection of nucleic acids and autoimmune antibodies.......Herein we describe fluorescent oligonucleotides prepared by click chemistry between novel alkyne-modified locked nucleic acid (LNA) strands and a series of fluorescent azides for homogeneous (all-in-solution) detection of nucleic acids and autoimmune antibodies....

  10. Construction of Nontoxic Polymeric UV-Absorber with Great Resistance to UV-Photoaging

    OpenAIRE

    Huang, Zhong; Ding, Aishun; Guo, Hao; Lu, Guolin; Huang, Xiaoyu

    2016-01-01

    In this article, we developed a series of new nontoxic polymeric UV-absorbers through covalently attaching a benzophenone derivative onto the main chain of poly(vinyl chloride) (PVC) via mild and quantitative click chemistry. Azide groups were firstly introduced into the backbone of PVC via a nucleophilic reaction without affecting polymeric skeleton. Copper-catalyzed Husigen-Click cycloaddition reaction was performed between the pendant azide groups of PVC and alkynyl of (2-hydroxy-4-(prop-2...

  11. PECH和GAP的玻璃化转变温度研究%Glass-transition Temperature of PECH and GAP

    Institute of Scientific and Technical Information of China (English)

    宋晓庆; 周集义; 王文浩; 王建伟; 白森虎

    2008-01-01

    @@ Glycidyl azide polymer (GAP) is one of the most recognized and prominent azide polymer. Because of its superior properties,GAP is used extensively as a high energetic binder or plasticizer in propellants to increase burning and specific impulse. It is very important to research on the glass-transition temperature (Tg) of GAP and its precursor PECH (poly-epichlorohydrin) due to the Tg of binders is the key factor which can influence low temperature properties of solid propellants.

  12. Polyglycerol Based Hydrogels for the Immobilization of Catalytically Active Enzymes and as Scaffolds for Cells

    OpenAIRE

    Dey, Pradip

    2015-01-01

    Im Rahmen dieser Doktorarbeit wurden Hydrogele basierend auf dendritischem Polyglycerol (dPG) entwickelt, welche unter Verwendung verschiedener Vernetzungsreaktionen, wie z. B. durch Amidverknüpfung oder durch ringspannungsvermittelte Azid-Alkin Cycloaddition (strain promoted azide alkyne cycloaddition, SPAAC), hergestellt wurden. Das Anwendungsspektrum dieser Hydrogele reicht von der Entwicklung enzymbasierter Biosensoren bis hin zu Trägermaterialien für Knorpelzellen. Enzymbasierte Bios...

  13. Functionalization of olefins by alkoximidoylnitrenes

    Energy Technology Data Exchange (ETDEWEB)

    Subbaraj, A.; Rao, O.S.; Lwowski, W. (New Mexico State Univ., Las Cruces (USA))

    1989-08-04

    (N-Cyano- and N-(methylsulfonyl)alkoxycarbimidoyl)nitrenes, generated in situ from the corresponding azides by 300-nm UV light, convert a variety of olefins cleanly and stereospecifically to the corresponding aziridines. These can readily be hydrolyzed to N-unsubstituted aziridines or ring-opened to allylic isoureas. The nitrenes can also be generated by thermolysis at 80{degree}C. The azides add to norbornene to give triazolines, which lose nitrogen to give the exo-aziridines.

  14. Flow-amperometric biosensor for respiratory toxins using myoglobin-adsorbed carbon-felt, based on an inhibitory effect on bioelectrocatalytic reduction of oxygen

    International Nuclear Information System (INIS)

    Novel, simple and highly sensitive reagentless amperometric flow-biosensor for respiratory toxins (i.e. azide and cyanide) has been developed by using myoglobin (Mb)-adsorbed carbon-felt (CF), based on the inhibitory event of azide and cyanide on the Mb-catalyzed O2 reduction. The Mb-adsorbed CF (Mb–CF) showed a sufficient bioelectrocatalytic activity for O2 reduction in the potential region from 0 to −0.4 V vs. Ag/AgCl at pH 5.0, due to the direct electron transfer (DET) between Mb-heme and the CF electrode. The heterogeneous electron transfer rate constant (ks) of the electrochemical redox reaction of Mb-heme–Fe(II)/(III) was estimated to be 15.5 s−1. This Mb–CF-catalyzed O2 reduction was reversibly inhibited by azide and cyanide, which bind to sixth coordination position of heme-iron center of Mb. When air-saturated 0.1 M phosphate/citrate buffer (pH 5.0) was used as a carrier under the applied potential of −0.2 V vs. Ag/AgCl, the steady-state current due to the Mb-catalyzed O2 reduction was reversibly inhibited by the injection (200 μl) of azide and cyanide, resulting in peak-shape current responses. The magnitude of the inhibition peak currents linearly increased with increasing concentrations of azide (up to 3 μM) and cyanide (up to 5 μM), and the detection limit of azide and cyanide were found to be 0.12 and 0.23 μM, respectively (S/N = 2). The apparent inhibition constant, K′i, of azide and cyanide were estimated to be 5.71 and 8.95 μM, respectively.

  15. Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

    Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

  16. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    International Nuclear Information System (INIS)

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe3O4@Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe3O4@Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe3O4@Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe3O4@Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe3O4@Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe3O4@Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

  17. Interaction of P-aminobenzoic acid with normal and sickel erythrocyte membrane: photoaffinity labelling of the binding sites

    Energy Technology Data Exchange (ETDEWEB)

    Premachandra, B.R.

    1986-03-05

    Electron microscopic studies revealed that P-Amino benzoic acid (PABA) could prevent eichinocytosis of red cells in vitro. Equilibrium binding studies with right side out membrane vesicles (ROV) revealed a similar number of binding sites (1.2-1.4 ..mu..mol/mg) and Kd (1.4-1.6 mM) values for both normal and sickle cell membranes. /sup 14/C-Azide analogue of PABA was synthesized as a photoaffinity label to probe its sites of interaction on the erythrocyte membranes. Competitive binding studies of PABA with its azide indicated that both the compounds share common binding sites on the membrane surface since a 20 fold excess of azide inhibited PABA binding in a linear fashion. The azide was covalently incorporated into the membrane components only upon irradiation (52-35% of the label found in the proteins and the rest in lipids). Electrophoretic analysis of photolabelled ROV revealed that the azide interacts chiefly with Band 3 protein. PABA inhibited both high and low affinity calcium (Ca) binding sites situated on either surface of the membrane in a non-competitive manner; however, Ca binding stimulated by Mg-ATP was not affected. Ca transport into inside out vesicles was inhibited by PABA; but it did not affect the calcium ATP-ase activity. The authors studies suggest that the mechanism of action of PABA is mediated by its interaction with Band 3 protein (anion channel), calcium channel and calcium binding sites of erythrocyte membrane.

  18. Pentafluorostyrene: A valuable and flexible material design tool when mastered by ATRP

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    Pentafluorostyrene is an intriguing monomer and has turned out to be an indispensable tool in the architecture of various functional materials. The ATRP merits with pentafluorostyrene was revealed a decade ago and since then especially the lability of the para-fluorine of pentafluorostyrene has...... scaffold for phophonates for polymer electrolyte membranes. This design idea was executed by use of CuAAC, where clickable azides were fabricated on the PSU (7 mol%) through lithiation chemistry at low temperature introducing first chloromethyl followed by conventional conversion of chloro groups to azides...... by sodium azide treatment. After clicking the two components together the poly(pentafluorostyrene) grafts were phosphonated. Graft copolymer (PSU-g-PhPFS) membranes could be cast that showed high thermal stability and proton conductivity. Soft silicone elastomers are materials in demand for actuators...

  19. Modular synthesis of a block copolymer with a cleavable linkage via “click” chemistry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A diblock copolymer poly(ethylene glycol)-block-polystyrene or PEG-b-PS with an olefinic double bond at the PEG and PS junction has been prepared by modular synthesis via"click"chemistry.This involved the synthesis of PS by atom transfer radical polymerization and the nucleophilic substitution of the terminal bromide group with azide to yield azide-terminated PS. PEG with an alkynyl terminal group was prepared from reacting carboxyl-end-functionalized PEG with 4-hydroxybut-2-enyl prop-2-ynyl succinate,which contained an alkynyl group as well as an olefin group.The PS and PEG polymers were linked via the 1,3-dipolar cycloaddition of the end azide and alkyne groups.The obtained copolymer was characterized by 1H NMR spectroscopy and size exclusion chromatography(SEC).SEC analysis indicated that the diblock copolymer produced could be readily cleaved by ozonolysis to regenerate the constituent homopolymers.

  20. Click Functionalization of a Dibenzocyclooctyne-Containing Conjugated Polyimine.

    Science.gov (United States)

    Kardelis, Vladimir; Chadwick, Ryan C; Adronov, Alex

    2016-01-18

    A conjugated poly(phenyl-co-dibenzocyclooctyne) Schiff-base polymer, prepared through polycondensation of dibenzocyclooctyne bisamine (DIBO-(NH2)2) with bis(hexadecyloxy)phenyldialdehyde, is reported. The resulting polymer, which has a high molecular weight (M(n)>30 kDa, M(w)>60 kDa), undergoes efficient strain-promoted alkyne-azide cycloaddition reactions with a series of azides. This enables quantitative modification of each repeat unit within the polymer backbone and the rapid synthesis of a conjugated polymer library with widely different substituents but a consistent degree of polymerization (DP). Kinetic studies show a second-order reaction rate constant that is consistent with monomeric dibenzocyclooctynes. Grafting with azide-terminated polystyrene and polyethylene glycol monomethyl ether chains of varying molecular weight resulted in the efficient syntheses of a series of graft copolymers with a conjugated backbone and maximal graft density. PMID:26643988

  1. Carbocation lifetimes and entropy of water addition to carbocations dependent on their stability

    Indian Academy of Sciences (India)

    V Jagannadham

    2003-02-01

    Iminodiazonium ions (-azidobenzyl carbocations) were produced in aqueous solution by chemical initiation (solvolysis) of benzyl-gem-diazides. Solvolysis reactions of benzyl-gem-diazides in water proceed by a stepwise mechanism through -azidobenzyl carbocation intermediates, which are captured by water to give the corresponding carbonyl compounds as the sole detectable products. Rate constant ratio / (M-1) for partitioning of the carbocation between reaction with azide ion and reaction with water was determined by analysis of azide common ion inhibition of the solvolysis reaction. Rate constants (s-1) for the reaction of the cation with solvent water were determined from the experimental values of / and solv, for the solvolysis of the benzyl-gem-diazides, using = 5 × 109 M-1 s-1 for diffusion-limited reactions of azide ion with -azidobenzyl carbocations. Values of 1/ were thus the lifetimes of the -azidobenzyl carbocations. From the study of effect of temperature on solv and the activation parameters are determined and discussed.

  2. Direct Observation of Carbamoylnitrenes.

    Science.gov (United States)

    Li, Hongmin; Wan, Huabin; Wu, Zhuang; Li, Dingqing; Bégué, Didier; Wentrup, Curt; Zeng, Xiaoqing

    2016-06-01

    As the prototype Curtius rearrangement reaction, carbamoyl azide decomposes into aminoisocyanate and molecular nitrogen. However, the key intermediate carbamoylnitrene was previously undetected, even though the decomposition of carbamoyl azides has been studied frequently since its discovery in the 1890s. Upon ArF laser (λ=193 nm) photolysis, the stepwise decomposition of the two simplest carbamoyl azides H2 NC(O)N3 and Me2 NC(O)N3, isolated in solid noble gas matrices, occurs with the formation of the corresponding carbamoylnitrenes H2 NC(O)N and Me2 NC(O)N. Both triplet species are characterized for the first time by combining matrix-isolation IR spectroscopy and quantum-chemical calculations. Subsequent visible-light irradiations cause efficient rearrangement of these nitrenes into the respective aminoisocyanates. PMID:27105905

  3. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    Science.gov (United States)

    Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

    2015-02-01

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe3O4@Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe3O4@Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe3O4@Au-FA nanoparticles.

  4. Effects of chemical fuel composition on energy generation from thermopower waves

    International Nuclear Information System (INIS)

    Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ∼2 V and an average peak specific power as high as 15 kW kg−1 were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s−1 and 157 mV, while they were 2 cm s−1 and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H+ and Na+ ions, as well as the formation of fiber-like structures, because of benzene π stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy

  5. Effects of chemical fuel composition on energy generation from thermopower waves

    Science.gov (United States)

    Yeo, Taehan; Hwang, Hayoung; Jeong, Dong-Cheol; Lee, Kang Yeol; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

    2014-11-01

    Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ˜2 V and an average peak specific power as high as 15 kW kg-1 were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s-1 and 157 mV, while they were 2 cm s-1 and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H+ and Na+ ions, as well as the formation of fiber-like structures, because of benzene π stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source.

  6. Antibody catalysis of peptide bond formation.

    OpenAIRE

    Jacobsen, J R; Schultz, P. G.

    1994-01-01

    An antibody generated against a neutral phosphonate diester transition-state (TS not equal to) analog catalyzes the formation of an amide bond between a phenylalanyl amino group and an acyl azide derived from L-alanine. The antibody is selective for L- vs. D-alanine and does not catalyze the hydrolysis of the acyl azide to an appreciable degree. A rate acceleration of 10,000-fold relative to the uncatalyzed reaction is observed. The antibody may achieve its catalytic efficiency both by acting...

  7. Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

    Directory of Open Access Journals (Sweden)

    Andreas Gansäuer

    2014-07-01

    Full Text Available An operationally simple, convenient, and mild strategy for the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute ‘second-generation’ functionalized titanocene building blocks for further synthetic elaboration. Our synthesis is modular and large numbers of the complexes can in principle be prepared in short periods of time. Some of the triazole-substituted titanocenes display high cyctotoxic activity against BJAB cells. Comparison of the most active complexes allows the identification of structural features essential for biological activity.

  8. Direct Light-up of cAMP Derivatives in Living Cells by Click Reactions

    Directory of Open Access Journals (Sweden)

    Yan Xu

    2013-10-01

    Full Text Available 8-Azidoadenosine 3′,5′-cyclic monophosphate (8-azido cAMP was directly detected in living cells, by applying Cu-free azide-alkyne cycloaddition to probe cAMP derivatives by fluorescence light-up. Fluorescence emission was generated by two non-fluorescent molecules, 8-azido cAMP as a model target and difluorinated cyclooctyne (DIFO reagent as a probe. The azide-alkyne cycloaddition reaction between 8-azido cAMP and DIFO induces fluorescence in 8-azido cAMP. The fluorescence emission serves as a way to probe 8-azido cAMP in cells.

  9. Enhanced reactivity of dinuclear Copper(I) acetylides in dipolar cycloadditions

    DEFF Research Database (Denmark)

    Ahlquist, Mårten Sten Gösta; Fokin, V.V.

    2007-01-01

    Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate i...... itself. These findings support the experimentally determined rate law and shed light on the origin of high reactivity of the in situ generated copper acetylides.......Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate...

  10. Chemical Modification of Poly(Vinyl Alcohol in Water

    Directory of Open Access Journals (Sweden)

    Houssein Awada

    2015-10-01

    Full Text Available Partial chemical modification of poly(vinyl alcohol (PVA was performed through tosylation followed by azidation. Amine functional PVA was also prepared by grafting propargylamine using click chemistry reaction. Through this approach, a tosyl group (a good leaving group, azide group (a group used in click chemistry and amine group (a group used for amidation were attached to PVA polymer chains. The three chemical modifications were performed in water. FTIR and XPS analysis confirmed the chemical modification after each step. Thermogravimetric analysis (TGA was used to study the thermal stability of the modified PVA.

  11. Improvement of Barley and Chenopodium species in the Andean region by induced mutations

    International Nuclear Information System (INIS)

    Experiments on the genetic improvement of barley (H. vulgare), quinoa (Chenopodium quinoa), and canahua (C. pallidicaule) were conducted in the field and greenhouse at the Centro de Investigaciones Nucleares at Viacha, using different concentrations and treatment durations of sodium azide (NaN3) to induce beneficial mutations. Greenhouse tests were conducted to establish the concentration and treatment duration for sodium azide. The treatments were applied and field evaluations were carried out in different generations to improve the germplasm available in the country, particularly in respect to environmental stresses such as frost, hail, and drought, which severely restrict yields. (author). 3 tabs

  12. Selective posttranslational modification of phage-displayed polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Tsao, Meng-Lin; Tian, Feng; Schultz, Peter

    2013-11-19

    The invention relates to posttranslational modification of phage-displayed polypeptides. These displayed polypeptides comprise at least one unnatural amino acid, e.g., an aryl-azide amino acid such as p-azido-L-phenylalanine, or an alkynyl-amino acid such as para-propargyloxyphenylalanine, which are incorporated into the phage-displayed fusion polypeptide at a selected position by using an in vivo orthogonal translation system comprising a suitable orthogonal aminoacyl-tRNA synthetase and a suitable orthogonal tRNA species. These unnatural amino acids advantageously provide targets for posttranslational modifications such as azide-alkyne [3+2] cycloaddition reactions and Staudinger modifications.

  13. Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

    Directory of Open Access Journals (Sweden)

    Paola Bonaccorsi

    2013-11-01

    Full Text Available A new class of molecules with a triptycene rigid core surrounded by six monosaccharide residues was synthesized. Hexakis(bromomethyl substituted triptycene was converted into a six-armed triptycene azide (2,3,6,7,14,15-hexakis(azidomethyl-9,10-dihydro-9,10-[1’,2’]benzenoanthracene. The key step of the synthesis was the cycloaddition of the azide to 2-propyn-1-yl β-D-gluco- or galactopyranosides. All products were isolated in good yields and were fully characterized.

  14. Diazido{(S-1-phenyl-N,N-bis[(2-pyridylmethyl]ethanamine}copper(II

    Directory of Open Access Journals (Sweden)

    Sankara Rao Rowthu

    2011-07-01

    Full Text Available In the title compound, [Cu(N32(C20H21N3], the CuII ion is coordinated by the three N atoms of the (S-1-phenyl-N,N-bis[(2-pyridylmethyl]ethanamine ligand and two N atoms from two azide anions, resulting in a distorted square-pyramidal environment. A weak intermolecular C—H...N hydrogen-bonding interaction between one pyridine group of the ligand and an azide N atom of an adjacent complex unit gives a one-dimensional chain structure parallel to the c axis.

  15. Synthesis of 1,2-dihydro-2-oxo-4-quinolinyl phosphates from 2-acyl-benzoic acids

    Science.gov (United States)

    He, Xinhua; Aglio, Tharcilla; Deschamps, Jeffrey R.; Rai, Rachita; Xue, Fengtian

    2015-01-01

    We report a facile synthesis of 1,2-dihydro-2-oxo-4-quinolinyl phosphates (1a-l) starting from 2-acyl-benzoic acids (2a-l) in the presence of phosphoryl azides via a one-pot cascade reaction involving a Curtius rearrangement, an intramolecular nucleophilic addition of the enol carbon to the isocyanate intermediate, and an addition-elimination of the enol oxygen to the phosphoryl azide. During the reaction three new bonds are formed under mild conditions to yield 1,2-dihydro-2-oxo-4-quinolinyl phosphates in modest yields. PMID:25937677

  16. Effect of ring size on the direction of rearrangement in bicyclic 1-tosyl-5-ethoxy-1,2,3-triazolines

    International Nuclear Information System (INIS)

    The authors determine that the title trazoline, formed in the reaction of tosyl azide with 1-epoxycyclohexene, is converted into ethyl N-tosylcyclopentencarbimidate, which is then converted into cyclopentanecarbohydrazide. The triazoline formed in the reaction of tosyl azide with 1-epoxycyclopentene is converted into N-(2-ethoxy-1-cyclopentenyl)toluenesulfonamide, the production of which indicates the intermediate formation of 2,3-trimethylene-1-tosyl-2-ethoxyaziridine. Consequently, the triazoline does not rearrange to ethyl N-tosylcyclobutanecarbimidate, in spite of the fact that it is substituted at the C-4 atom. Data on spin-spin coupling constants and chemical shift derived from the NMR spectra are analyzed

  17. Induced mutation for disease resistance in rice with special reference to blast, bacterial blight and tungro

    International Nuclear Information System (INIS)

    Rice varieties Ratna, Pusa 2-21, Vijaya and Pankaj have been treated with gamma rays, EMS or sodium azide to improve their resistance against blast, bacterial leaf blight or tungro virus. For blast and tungro, mutants with improved resistance were selected. Variation in reaction to bacterial leaf blight has been used in crossbreeding to accumulate genes for resistance. (author)

  18. Functional Materials by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede

    Dette ph.d.-projekt har fokuseret på fremstilling af nye funktionelle materialer ud fra konceptet bag ”Click” kemi. Her er specielt den selektive 1,3-dipolare cykloaddition imellem azider og alkyner under kobber katalyse anvendt til kobling af funktionelle grupper til polymerer. I projektet er de...

  19. Bioorthogonal fluorescent labeling of functional G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Tian, He; Naganathan, Saranga; Kazmi, Manija A;

    2014-01-01

    contrast, the strain-promoted [3+2] azide-alkyne cycloaddition (SpAAC) with dibenzocyclooctyne (DIBO) reagents yielded stoichiometric conjugates with azF-rhodopsin while undergoing negligible background reactions. As one application of this technique, we used Alexa488-rhodopsin to measure the kinetics of...

  20. Halomethyl-cobalt(bis-acetylacetonate) for the controlled synthesis of functional polymers.

    Science.gov (United States)

    Demarteau, Jérémy; Kermagoret, Anthony; German, Ian; Cordella, Daniela; Robeyns, Koen; De Winter, Julien; Gerbaux, Pascal; Jérôme, Christine; Debuigne, Antoine; Detrembleur, Christophe

    2015-10-01

    Novel organocobalt complexes featuring weak C-CoL2 bonds (L = acetylacetonate) are prepared and used as sources of halomethyl radicals. They permit the precision synthesis of α-halide functionalized and telechelic polymers in organic media or in water. Substitution of halide by azide allows derivatization of polymers using the CuAAC click reaction. PMID:26273709

  1. One-pot Microwave-Assisted Synthesis of 1H-Phenanthro[9,10- d][1,2,3]triazole

    Directory of Open Access Journals (Sweden)

    Mehrak Faraji

    2008-09-01

    Full Text Available In this study, a fast and good yield one-pot microwave-assisted synthesis (45 seconds of 1H-phenanthro[9,10-d][1,2,3]triazole by a 1,3-dipolar cycloaddition reaction of sodium azide and 9-bromophenanthrene in the presence of potassium tert-butoxide in DMSO as solvent is reported.

  2. Uncovering the Role of Metal Catalysis in Tetrazole Formation by an In Situ Cycloaddition Reaction: An Experimental Approach.

    Science.gov (United States)

    Zhong, Di-Chang; Wen, Ya-Qiong; Deng, Ji-Hua; Luo, Xu-Zhong; Gong, Yun-Nan; Lu, Tong-Bu

    2015-09-28

    Using an experimental approach, the role of metal catalysis has been investigated in the in situ cycloaddition reaction of nitrile with azide to form tetrazoles. It has been shown that metal catalysis serves to activate the cyano group in the nitrile reagent by a coordinative interaction. PMID:26293313

  3. On-Surface Synthesis by Click Chemistry Investigated by STM and XPS

    DEFF Research Database (Denmark)

    Vadapoo, Sundar Raja

    2014-01-01

    molecular electronics and surface functionalization. In this thesis, a well-defined click chemistry approach is followed, with the study of azide-alkyne cycloaddition on Cu(111) surface in UHV environment. A successful achievement of the click reaction product via on-surface synthesis has been shown, which...

  4. Well-defined ABA- and BAB-type block copolymers of PDMAEMA and PCL

    DEFF Research Database (Denmark)

    Bruce, Carl; Javakhishvili, Irakli; Fogelstrom, Linda; Carlmark, Anna; Hvilsted, Søren; Malmstrom, Eva

    2014-01-01

    -opening polymerisation of epsilon-CL, atom transfer radical polymerisation of DMAEMA and end-group conversion, performed through either acylation or azide-alkyne "click" chemistry. All samples were analysed by size exclusion chromatography where it was found that the evaluation of PDMAEMA-containing polymers was...

  5. Miktoarm core-crosslinked star copolymers with biologically active moieties on peripheries

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2010-01-01

    ) of epsilon-caprolactone (epsilon-CL) initiated by functional alcohols provides alkyne or azide end-capped linear PCL chains. Further derivatization of the hydroxyl chain ends of these hetero-telechelic macromolecules by methacrylic acid (MA), and subsequent Cu(I) mediated "click" coupling of terminal...

  6. Novel silicone compatible cross-linkers for controlled functionalization of PDMS networks

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren; Skov, Anne Ladegaard

    2013-01-01

    azide-functional cross-linker by click chemistry. The dipole cross-linkers are used to prepare PDMS elastomers of various chains lengths providing different network densities. The functionalized cross-linkers are incorporated successfully into the networks and are well distributed as determined by the...

  7. Dipolar cross-linkers for PDMS networks with enhanced dielectric permittivity and low dielectric loss

    DEFF Research Database (Denmark)

    Bahrt, Frederikke; Daugaard, Anders Egede; Hvilsted, Søren; Benslimane, Mohamed Yahia; Skov, Anne Ladegaard

    2013-01-01

    -(4-((4-nitrophenyl)diazenyl)phenoxy)-prop-1-yn-1-ylium, with a synthesized silicone compatible azide-functional cross-linker by click chemistry. The thermal, mechanical and electromechanical properties were investigated for PDMS films with 0 to 3.6 wt% of dipole-cross-linker. The relative dielectric permittivity was...

  8. Antimutagenic potential of curcumin on chromosomal aberrations in Allium cepa

    Institute of Scientific and Technical Information of China (English)

    RAGUNATHAN Irulappan; PANNEERSELVAM Natarajan

    2007-01-01

    Turmeric has long been used as a spice and food colouring agent in Asia. In the present investigation, the antimutagenic potential of curcumin was evaluated in Allium cepa root meristem cells. So far there is no report on the biological properties of curcumin in plant test systems. The root tip cells were treated with sodium azide at 200 and 300 μg/ml for 3 h and curcumin was given at 5, 10 and 20 μg/ml for 16 h, prior to sodium azide treatment. The tips were squashed after colchicine treatment and the cells were analyzed for chromosome aberration and mitotic index. Curcumin induces chromosomal aberration in Allium cepa root tip cells in an insignificant manner, when compared with untreated control. Sodium azide alone induces chromosomal aberrations significantly with increasing concentrations. The total number of aberrations was significantly reduced in root tip cells pretreated with curcumin. The study reveals that curcumin has antimutagenic potential against sodium azide induced chromosomal aberrations in Allium cepa root meristem cells. In addition, it showed mild cytotoxicity by reducing the percentage of mitotic index in all curcumin treated groups, but the mechanism of action remains unknown. The antimutagenic potential of curcumin is effective at 5 μg/ml in Allium cepa root meristem cells.

  9. A DOTA-peptide conjugate by copper-free click chemistry

    OpenAIRE

    Martin, Molly E.; Parameswarappa, Sharavathi G.; O’Dorisio, M. Sue; Pigge, F. Christopher; Schultz, Michael K.

    2010-01-01

    Attachment of DOTA to a novel monofluoro-cyclooctyne facilitates bioconjugation to an azide-modified peptide via Cu-free click chemistry. The resulting conjugate was radiolabeled with 111In to afford a potential targeted molecular imaging agent with high specific activity and in excellent radiochemical purity.

  10. Involvement of sulfide:quinone oxidoreductase in sulfur oxidation of an acidophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans NASF-1.

    Science.gov (United States)

    Wakai, Satoshi; Kikumoto, Mei; Kanao, Tadayoshi; Kamimura, Kazuo

    2004-12-01

    The effects of cyanide, azide, and 2-n-Heptyl-4-hydroxy-quinoline-N-oxide (HQNO) on the oxidation of ferrous ion or elemental sulfur with Acidithiobacillus ferrooxidans NASF-1 cells grown in iron- or sulfur-medium were examined. The iron oxidation of both iron- and sulfur-grown cells was strongly inhibited by cyanide and azide, but not by HQNO. Sulfur oxidation was relatively resistant to cyanide and azide, and inhibited by HQNO. Higher sulfide oxidation, ubiquinol dehydrogenase activity, and sulfide:quinone oxidoreductase (SQR) activity were observed in sulfur-grown cells more than in iron-grown cells. Sulfide oxidation in the presence of ubiquinone with the membrane fraction was inhibited by HQNO, but not by cyanide, azide, antimycin A, and myxothiazol. The transcription of three genes, encoding an aa(3)-type cytochrome c oxidase (coxB), a bd-type ubiquinol oxidase (cydA), and an sqr, were measured by real-time reverse transcription polymerase chain reaction. The transcriptional levels of coxB and cydA genes were similar in sulfur- and iron-grown cells, but that of sqr was 3-fold higher in sulfur-grown cells than in iron-grown cells. A model is proposed for the oxidation of reduced inorganic sulfur compounds in A. ferrooxidans NASF-1 cells. PMID:15618623

  11. Multicomponent click synthesis of potentially biologically active triazoles catalysed by copper nanoparticles on activated carbon in water

    OpenAIRE

    Alonso Valdés, Francisco; Moglie, Yanina; Radivoy, Gabriel; Yus Astiz, Miguel

    2011-01-01

    A variety of potentially biologically active 1,2,3-triazoles, derived from (–)-menthol, lactic acid, D-glucose, oestrone, cholesterol, and phenacetin, have been synthesised through the multicomponent alkyne-azide 1,3-dipolar cycloaddition catalysed by copper nanoparticles on activated carbon in neat water.

  12. Complex Surface Concentration Gradients by Stenciled "Electro Click Chemistry"

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede;

    2010-01-01

    Complex one- or two-dimensional concentration gradients of alkynated molecules are produced on azidized conducting polymer substrates by stenciled "electro click chemistry". The latter describes the local electrochemical generation of catalytically active Cu(I) required to complete a "click...

  13. 3+2-Dipolar cycloaddition of dianhydrohexitol azidoderivatives with N-arylmaleimides

    Science.gov (United States)

    Gella, I. M.; Babak, N. L.; Drushlyak, T. G.; Shishkina, S. V.; Musatov, V. I.; Lipson, V. V.

    2015-11-01

    Dianhydrohexitol azides dipolar 3+2 cycloaddition with N-arylmaleimides has been studied with NMR (1H and 13C, COSY, NOESY and HSQC) and X-ray analysis. In spite of low asymmetrical induction in this reaction, diastereomerically pure products have been obtained. These products are interesting over their structural similarity to griseolic acid derivatives and dihydropyrrolotriazoles, significant for pharmaceutics.

  14. Azido-Iodo-N-Benzyl Derivatives of threo-Methylphenidate (Ritalin, Concerta): Rational Design, Synthesis, Pharmacological Evaluation, and Dopamine Transporter Photoaffinity Labeling

    OpenAIRE

    Lapinsky, David J.; Velagaleti, Ranganadh; Yarravarapu, Nageswari; Liu, Yi; Huang, Yurong; Surratt, Christopher K.; Lever, John R.; Foster, James D.; Acharya, Rejwi; Vaughan, Roxanne A.; Deutsch, Howard M.

    2010-01-01

    In contrast to tropane-based compounds such as benztropine and cocaine, non-tropane-based photoaffinity ligands for the dopamine transporter (DAT) are relatively unexplored. Towards addressing this knowledge gap, ligands were synthesized in which the piperidine nitrogen of 3- and 4-iodomethylphenidate was substituted with a benzyl group bearing a photoreactive azide. Analog (...

  15. Drug: D07697 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available AZIDES C03BX Other low-ceiling diuretics C03BX03 Cicletanine D07697 Cicletanine h...ATC) classification [BR:br08303] C CARDIOVASCULAR SYSTEM C03 DIURETICS C03B LOW-CEILING DIURETICS, EXCL. THI

  16. Patterned porous silicon photonic crystals with modular surface chemistry for spatial control of neural stem cell differentiation.

    Science.gov (United States)

    Huang, Tiffany H; Pei, Yi; Zhang, Douglas; Li, Yanfen; Kilian, Kristopher A

    2016-06-01

    We present a strategy to spatially define regions of gold and nanostructured silicon photonics, each with materials-specific surface chemistry, for azide-alkyne cycloaddition of different bioactive peptides. Neural stem cells are spatially directed to undergo neurogenesis and astrogenesis as a function of both surface properties and peptide identity. PMID:27173986

  17. A fluorescent, photochromic and thermochromic trifunctional material based on a layered metal-viologen complex.

    Science.gov (United States)

    Wan, Fang; Qiu, Li-Xia; Zhou, Liang-Liang; Sun, Yan-Qiong; You, Yi

    2015-11-14

    The azide anion as an energy acceptor and an electron donor has been introduced into a metal-viologen compound to form a 2D layered viologen-based trifunctional material, which exhibits the rare discolored function of reversible photochromism and thermochromism. Interestingly, its fluorescence can be switched by visible light irradiation and heating in air. PMID:26445888

  18. Heterogeneous Catalysis through Microcontact Printing

    NARCIS (Netherlands)

    Spruell, Jason M.; Sheriff, Bonnie A.; Rozkiewicz, Dorota I.; Dichtel, William R.; Rohde, Rosemary D.; Reinhoudt, David N.; Stoddart, Fraser; Heath, James R.

    2008-01-01

    Minting a Stamp: The preparation of copper metal-coated elastomeric stamps and their use in catalyzing the Cu-catalyzed azide-alkyne cycloaddition reaction heterogeneously through microcontact printing is described. This StampCat process is compared to other conventional surface-functionalization te

  19. Synthesis and Characterization of [60]Fullerene Ferrocenylmethyl Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new [60]fullerene ferrocenylmethyl derivatives have been prepared via different approaches and characterized by UV-Vis、 FT-IR、 NMR、 FAB-MS spectra and VPO. The second approach , i.e reacting fullerene with ferrocenylmethyl azide directly, was never reported as yet.

  20. Bimetallic nickel complexes for selective CO2 carbon capture and sequestration.

    Science.gov (United States)

    Möller, F; Merz, K; Herrmann, C; Apfel, U-P

    2016-01-21

    Herein we report a dinickel azacryptand complex that enables fast, selective, and tight CO2 binding from air. Exploiting the affinity of the cavitand towards azides, CO2 release was observed. Despite the stability of the azido complex, UV irradiation under atmospheric conditions proved to be a suitable pathway for N3(-) replacement by CO2. PMID:26666316

  1. Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles

    Science.gov (United States)

    Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...

  2. Homotypic aggregation of human cell lines by HLA class II-, class Ia- and HLA-G-specific monoclonal antibodies

    DEFF Research Database (Denmark)

    Odum, Niels; Ledbetter, J A; Martin, P;

    1991-01-01

    two anti-beta 2-microglobulin mAb had variable, weak effects. The aggregation response was an active, temperature-sensitive process which was almost totally abrogated by azide and by cytochalasins B and E, but unaffected by colchicine, EDTA, aphidicolin, actinomycin D and protein tyrosine kinase...

  3. Mildew-resistant mutants induced in North American two- and six-rowed malting barley cultivars

    DEFF Research Database (Denmark)

    Molina-Cano, J.L.; Simiand, J.P.; Sopena, A.;

    2003-01-01

    Mildew-resistant mutants were induced with sodium azide in three North American malting barley cultivars, two in the six-rowed Ursula (URS1 and URS2), one in the six-rowed Gertrud (GER1), and one in the two-rowed Prudentia (PRU1). Two of the mutants, URS1 and PRU1, showed complete resistance and...

  4. Azido analogs of neuroactive steroids

    Czech Academy of Sciences Publication Activity Database

    Černý, Ivan; Vidrna, Lukáš; Pouzar, Vladimír; Borovská, Jiřina; Vyklický, Vojtěch; Chodounská, Hana; Vyklický ml., Ladislav

    Chicago : -, 2011. P2.28-P2.28. [Congress on Steroid Research. 27.03.2011-29.03.2011, Chicago] R&D Projects: GA MZd(CZ) NS10365 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : neuroactive steroids * NMDA receptor * steroid azide Subject RIV: CC - Organic Chemistry

  5. Nano indium oxide as a recyclable catalyst for the synthesis of arylaminotetrazoles

    Indian Academy of Sciences (India)

    Siavash Bahari; Mehdi Ahmadi Sabegh

    2013-01-01

    Nano indium oxide is an effective heterogeneous catalyst for the reaction between aryl cyanamides and sodium azide to synthesize the arylaminotetrazoles in good yields. This method has advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered and reused in good yields.

  6. Nitride-bridged triiron complex and its relevance to dinitrogen activation.

    Science.gov (United States)

    Ermert, David M; Gordon, Jesse B; Abboud, Khalil A; Murray, Leslie J

    2015-10-01

    Using a simple metathesis approach, the triiron(II) tribromide complex Fe3Br3L (1) reacts with tetrabutylammonium azide to afford the monoazide dibromide analogue Fe3(Br)2(N3)L (2) in high yield. The inclusion of azide was confirmed by IR spectroscopy with a ν(N3) = 2082 cm(-1) as well as combustion analysis and X-ray crystallography. Heating 2 in the solid state results in the complete loss of the azide vibration in the IR spectra and the isolation of the olive-green mononitride complex Fe3(Br)2(N)L (3). Solution magnetic susceptibility measurements support that the trimetallic core within 2 is oxidized upon generation of 3 (5.07 vs 3.09 μB). Absorption maxima in the UV-visible-near-IR (NIR) spectra of 2 and 3 support the azide-to-nitride conversion, and a broad NIR absorption centered at 1117 nm is similar to that previously reported for the intervalence charge-transfer band for a mixed-valent nitridodiiron cluster. The cyclic voltammograms recorded for 3 are comparable to those of 1 with no reductive waves observed between ∼0 and -2.5 V (vs Fc/Fc(+)), whereas a reversible one-electron redox process is observed for Fe3(NH2)3L (4). These results suggest that intercluster cooperativity is unlikely to predominate the dinitrogen reduction mechanism when 1 is treated with KC8 under N2. PMID:26052673

  7. The Formation of Large-Area Conducting Graphene-Like Platelets

    NARCIS (Netherlands)

    Salvio, Riccardo; Krabbenborg, Sven; Naber, Wouter J.M.; Velders, Aldrik H.; Reinhoudt, David N.; Wiel, van der Wilfred G.

    2009-01-01

    The treatment of a suspension of graphite oxide (GO) with sodium azide leads to a material that, after reduction, features amino groups at the top and bottom of the sheets. These groups react through microcontact printing with an isothiocyanate monolayer on a silicon oxide substrate to form covalent

  8. Comparison of methods for specific depletion of ATP in Salmonella typhimurium.

    OpenAIRE

    Johnson, M. S.; Taylor, B L

    1993-01-01

    Three methods of ATP depletion in Salmonella typhimurium were compared. ATP concentrations were lowest after arsenate treatment. Arsenate or alpha-methylglucoside-plus-azide treatment nonspecifically lowered all nucleotide triphosphate levels. Histidine starvation in a hisF mutant was relatively specific for ATP depletion and therefore has potential in distinguishing ATP-dependent processes from processes dependent on other nucleotides.

  9. Efficient and highly enantioselective formation of the all-carbon quaternary stereocentre of lyngbyatoxin A

    DEFF Research Database (Denmark)

    Vital, Paulo J.V.; Tanner, David

    2006-01-01

    Indole 25, an advanced intermediate in a projected enantioselective total synthesis of lyngbyatoxin A 1, was prepared from allylic alcohol 11 in 9 steps and >95% ee, key transformations being the enantiospecific rearrangement of vinyl epoxide 14 and the Hemetsberger-Knittel reaction of azide 24....

  10. The Development of a Versatile Trifunctional Scaffold for Biological Applications

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Václav; Pícha, Jan; Fabre, Benjamin; Buděšínský, Miloš; Lepšík, Martin; Jiráček, Jiří

    2015-01-01

    Roč. 2015, č. 17 (2015), s. 3689-3701. ISSN 1434-193X R&D Projects: GA ČR GA14-17305S Institutional support: RVO:61388963 Keywords : solid-phase synthesis * protein mimics * click chemistry * alkynes * copper * azides Subject RIV: CC - Organic Chemistry Impact factor: 3.065, year: 2014

  11. Biochemical Oxygen Demand and Dissolved Oxygen. Training Module 5.105.2.77.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the azide modification of the Winkler dissolved oxygen test and the electronic dissolved oxygen meter test procedures for determining the dissolved oxygen and the biochemical oxygen demand of a wastewater sample. Included are…

  12. Synthesis and Reactions of 2,6-Diazidopurine Deoxynucleoside

    OpenAIRE

    Ozols, K; Bizdēna, Ē

    2013-01-01

    In recent years number of novel 1,2,3-triazolylpurine nucleosides have been synthesized including compounds with biological activity: adenosine receptor antagonists and agonists, anticancer and antiviral agents. In this research synthesis of 2,6-bistriazolyl deoxynucleosides in Cu catalysed 1,3-dipolar azide-alkyne cycloaddition reaction (Click reaction) has been investigated.

  13. Regioselective Nucleophilic Aromatic Substitution of 2,6-Bis-(1,2,3-Triazolyl)-Purine Derivatives with Various Nucleophiles

    OpenAIRE

    Novosjolova, I; Bizdēna, Ē; Turks, M

    2013-01-01

    A novel class of bis-triazolyl purine nucleosides were obtained from 2,6-diazido precursors via copper (I) catalyzed azide-alkyne cycloaddition. These intermediates appeared to be very reactive towards N- and S-nucleophiles and thus selectively gave C(6)-substituted analogs with triazolyl moiety at C(2)-position. The obtained 2-triazolyl purine derivatives exhibit interesting fluorescence properties.

  14. Click, Substitute and Fluoresce: Synthesis and Applications of 2,6-Di-(1,2,3-triazolyl)-purine Nucleosides

    OpenAIRE

    Novosjolova, I; Kovaļovs, A; Bižāne, I; Bizdēna, Ē; Turks, M

    2012-01-01

    A novel class of ditriazolylpurine nucleosides were ob-tained from 2,6-diazido precursors via copper catalyzed azide-alkyne cycloaddition. These intermediates ap-peared to be very reactive towards N- and S-nucleophiles and thus selectively gave C(6)-substituted analogs with triazolyl moiety at C(2)-position. The latter products exhibit interesting fluorescence properties.

  15. "Click" Approach to the Synthesis of 2,6-Bis(1,2,3-triazolyl)purine Deoxynucleosides

    OpenAIRE

    Ozols, K; Bizdēna, Ē

    2013-01-01

    Azide-alkyne 1,3-dipolar cycloaddition reaction (click reaction) has been found to be useful in nucleoside, nucleotide and oligonucleotide chemistry. In last years a number of 1,2,3-triazolylnucleoside derivatives have been synthesized and investigated, leading to discovery of substances with antiviral and anticancer activity, enzyme inhibitors, adenosine receptor agonists and antagonists.

  16. Sulfonamide bearing oligonucleotides: Simple synthesis and efficient RNA recognition

    DEFF Research Database (Denmark)

    Kumar, P.; Chandak, N.; Nielsen, P.;

    2012-01-01

    Four pyrimidine nucleosides wherein a benzensulfonamide group is linked to the C-5 position of the uracil nucleobase through a triazolyl or an alkynyl linker were prepared by Cu(I)-assisted azide-alkyne cycloadditions (CuAAC) or Sonogashira reactions, respectively, and incorporated into oligonucl...

  17. Comparative study of chemical and physical methods for distinguishing between passive and metabolically active mechanisms of water contaminant removal by biofilms.

    Science.gov (United States)

    Adapa, L M; Azimi, Y; Singh, S; Porcelli, D; Thompson, I P

    2016-09-15

    In this study, physical and chemical approaches were employed to distinguish between passive and active mechanisms in biofilms removing contaminants in waste waters and their relative merits were assessed. Respiration, post-exposure recovery and scanning electron microscopic analysis demonstrated that both ultraviolet (UV) treatment (300 mJ/cm(2)) and sodium azide (10 mM) completely inhibited metabolic activity at 5 and 24 h exposure, respectively, whilst not damaging the integrity of the biofilms. Amongst the commonly used chemical inhibitors, only sodium azide showed complete inhibition after 24 h incubation with only about 10% (±4%) of biofilm carbon released into the bulk solution, compared to 33-41% (±8%) when exposed to 5 mM and 10 mM 2,4-dinitrophenol (DNP) and 69-80% (±5%) when exposed to 2% and 5% w/v formalin, respectively. Biofilm inhibition with UV and sodium azide was found to be equally effective at inhibiting biofilms for treatment of triethanolamine (TEA) and benzotriazole (BTA): the results confirming that the dominant removal mechanism was biodegradation. However, the rates of glucose removal by sodium azide-inhibited biofilms were similar to controls, suggesting that chemical inhibitors were not effective for distinguishing the removal mechanisms of simple sugars. Statistically similar amounts of metal were removed by biofilms treated with UV and sodium azide in zinc, copper and cadmium single-systems: the results indicated that the removal mechanism is predominantly a passive biosorption process. PMID:27314554

  18. Conjugating folate on superparamagnetic Fe{sub 3}O{sub 4}@Au nanoparticles using click chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Xiaofang, E-mail: xfshen@jiangnan.edu.cn; Ge, Zhaoqiang; Pang, Yuehong

    2015-02-15

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe{sub 3}O{sub 4}@Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe{sub 3}O{sub 4}@Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe{sub 3}O{sub 4}@Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe{sub 3}O{sub 4}@Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe{sub 3}O{sub 4}@Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe{sub 3}O{sub 4}@Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry.

  19. High-yield clicking and dissociation of doxorubicin nanoclusters exhibiting differential cellular uptakes and imaging.

    Science.gov (United States)

    Kim, Hye Sung; Yoon, Sujin; Son, Young Ju; Park, Yeonju; Jung, Young Mee; Yoo, Hyuk Sang

    2015-11-10

    Gold nanoparticles (AuNPs) and quantum dots (Qdots) were clicked into doxorubicin nanoclusters that showed enzyme-dependent dissociation behaviors for differential cellular uptakes and imaging. The AuNPs were co-functionalized with doxorubicin (DOX) and azide-terminated polymer (DOX/azide@AuNP), while an enzyme-cleavable peptide and alkyne-terminated polymer were sequentially conjugated on Qdot surface (Alkyne-MMP@Qdot). Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and fluorescence imaging detected the azide and alkyne groups on DOX/azide@AuNP and Alkyne-MMP@Qdot, respectively, and the click-reactivity was also confirmed. In the presence of the catalyst, two nanoparticles were clicked to doxorubicin nanoclusters, which increased the volume of the particles ca. 343-fold within 30min. Upon matrix metalloproteinase-2 (MMP-2) digestion, the nanoclusters were clearly dissociated into smaller particles, and the fluorescence of the quenched Qdot was also recovered, which suggests that the nanoclusters respond to MMP-2 concentrations and can thus be employed for cancer imaging. Confocal microscopy and an elemental analysis of the cancer cells revealed that the cellular uptakes of doxorubicin nanoclusters significantly increased at higher MMP-2 concentrations, and doxorubicin could also be cleaved for anti-cancer effects. In vivo and in vitro cytotoxicity assay accordingly showed that the cytotoxicity of doxorubicin nanoclusters against cancer cells increased in MMP-2-rich environments such as tumor site. Thus, these nanoclusters containing DOX/azide@AuNP and Alkyne-MMP@Qdot are expected to be multifunctional carriers for targeted anti-cancer treatments and imaging. PMID:26315815

  20. Using click chemistry to modify block copolymers and their morphologies

    Science.gov (United States)

    Wollbold, Johannes

    Microphase separated block copolymers (BCPs) are emerging as promising templates and scaffolds for the fabrication of nanostructured materials. To achieve the desired nanostructures, it is necessary to establish convenient approaches to control the morphology of BCPs. It remains challenging to induce morphological transitions of BCPs via external fields. Click chemistry, especially alkyne/azide click chemistry, has been widely used to synthesize novel functionalized materials. Here, we demonstrate that alkyne/azide click chemistry can be used as an efficient approach to chemically modify BCPs and therefore induce morphological transitions. Alkyne-functionalized diblock copolymers (di-BCPs) poly(ethylene oxide)- block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) have been successfully synthesized. When the di-BCP is blended with an azide additive Rhodamine B azide and annealed at elevated temperatures, click reaction occurs between the two components. With the Rhodamine B structure attached to the polymer backbone, the di-BCP shows dramatic change in the interactions between the two blocks and the volume fraction of each block. As a result, morphological transitions, such as disorder-to-order transitions (DOTs) and order-to-order transitions (OOTs), are observed. The reaction kinetics and morphology evolution during the click chemistry induced DOTs have been investigated by in-situ and ex-situ characterizations, and fast kinetics properties are observed. Microphase separated morphologies after the DOTs or OOTs are dictated by the composition of neat di-BCPs and the mole ratio between the alkyne and azide groups. The DOTs of PEO-b-P(nBMA-r-PgMA) di-BCPs induced by alkyne/azide click chemistry have also been achieved in thin film geometries, with comparable kinetics to bulk samples. The orientation of the microdomains is dependent on the grafting density of Rhodamine B structure as well as film thickness. At higher grafting densities

  1. Syntheses of Sulfo-Glycodendrimers Using Click Chemistry and Their Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Tomohiro Fukuda

    2012-10-01

    Full Text Available A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated dendrimers showed affinity for proteins, including the lectin wheat germ agglutinin and amyloid beta peptide (1-42. The dendrimers of G1 and G2 in particular showed the largest affinity for the proteins. The addition of the sulfonated GlcNAc dendrimers of G1 and G2 exhibited an inhibition effect on the aggregation of the amyloid beta peptide, reduced the b-sheet conformation, and led to a reduction in the level of nanofiber formation.

  2. Strain-promoted copper free click chemistry for 64Cu radiolabeling of integrin-αvβ6 targeted peptide

    International Nuclear Information System (INIS)

    Strain promoted copper free click chemistry offers a fast and efficient method for preparation of radio labeled molecular probes and pre-targeted imaging in vivo. The fast reaction kinetics, driven by the release of strain energy ranging from 10-19 kcal/mol for cyclooctynes, precludes the need for toxic copper catalyst for chemical ligation between alkynes and azides. In particular this catalyst free approach provides a favorable platform for synthesis of radiometalated probes requiring macrocycle chelates for formation of stable and kinetically inert complexes where Cu(I) can interfere with metal chelates. In present studies DOTA-ADIBO (azadibenzocyclooctyne amine), a strained chelate-alkyne system has been constructed for bioconjugation with the azide-modified PEGylated peptide, N3-Ala-PEG28-A20FMDV2 and radiolabeled with (64Cu) Cu for assessment as a integrin-αvβ6, targeting molecular probe

  3. Chemical Architecture and Applications of Nucleic Acid Derivatives Containing 1,2,3-Triazole Functionalities Synthesized via Click Chemistry

    Directory of Open Access Journals (Sweden)

    Wei Gong

    2012-10-01

    Full Text Available There is considerable attention directed at chemically modifying nucleic acids with robust functional groups in order to alter their properties. Since the breakthrough of copper-assisted azide-alkyne cycloadditions (CuAAC, there have been several reports describing the synthesis and properties of novel triazole-modified nucleic acid derivatives for potential downstream DNA- and RNA-based applications. This review will focus on highlighting representative novel nucleic acid molecular structures that have been synthesized via the “click” azide-alkyne cycloaddition. Many of these derivatives show compatibility for various applications that involve enzymatic transformation, nucleic acid hybridization, molecular tagging and purification, and gene silencing. The details of these applications are discussed. In conclusion, the future of nucleic acid analogues functionalized with triazoles is promising.

  4. Click-to-Chelate: Development of Technetium and Rhenium-Tricarbonyl Labeled Radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt

    2013-03-01

    Full Text Available The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (biomolecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

  5. Expanding the chemical scope of RNA:methyltransferases to site-specific alkynylation of RNA for click labeling

    Science.gov (United States)

    Motorin, Yuri; Burhenne, Jürgen; Teimer, Roman; Koynov, Kaloian; Willnow, Sophie; Weinhold, Elmar; Helm, Mark

    2011-01-01

    This work identifies the combination of enzymatic transfer and click labeling as an efficient method for the site-specific tagging of RNA molecules for biophysical studies. A double-activated analog of the ubiquitous co-substrate S-adenosyl-l-methionine was employed to enzymatically transfer a five carbon chain containing a terminal alkynyl moiety onto RNA. The tRNA:methyltransferase Trm1 transferred the extended alkynyl moiety to its natural target, the N2 of guanosine 26 in tRNAPhe. LC/MS and LC/MS/MS techniques were used to detect and characterize the modified nucleoside as well as its cycloaddition product with a fluorescent azide. The latter resulted from a labeling reaction via Cu(I)-catalyzed azide-alkyne 1,3-cycloaddition click chemistry, producing site-specifically labeled RNA whose suitability for single molecule fluorescence experiments was verified in fluorescence correlation spectroscopy experiments. PMID:21037259

  6. Metal-Free Route for the Synthesis of 4-Acyl-1,2,3-Triazoles from Readily Available Building Blocks.

    Science.gov (United States)

    Thomas, Joice; Goyvaerts, Vince; Liekens, Sandra; Dehaen, Wim

    2016-07-11

    Functionalized 1,2,3-triazole heterocycles have been known for a long time and hold an extraordinary potential in diverse research areas ranging from medicinal chemistry to material science. However, the scope of therapeutically important 1-substituted 4-acyl-1H-1,2,3-triazoles is much less explored, probably due to the lack of synthetic methodologies of good scope and practicality. Here, we describe a practical and efficient one-pot multicomponent reaction for the synthesis of α-ketotriazoles from readily available building blocks such as methyl ketones, N,N-dimethylformamide dimethyl acetal, and organic azides with 100 % regioselectivity. This reaction is enabled by the in situ formation of an enaminone intermediate followed by its 1,3-dipolar cycloaddition reaction with an organic azide. We effectively utilized the developed strategy for the derivatization of various heterocycles and natural products, a protocol which is difficult or impossible to realize by other means. PMID:27172985

  7. Gadolinium(III-DOTA Complex Functionalized with BODIPY as a Potential Bimodal Contrast Agent for MRI and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Matthias Ceulemans

    2015-11-01

    Full Text Available The synthesis and characterization of a novel gadolinium(III DOTA complex functionalized with a boron-dipyrromethene derivative (BODIPY is described. The assembly of the complex relies on azide diazotransfer chemistry in a copper tube flow reactor. The azide thus formed is coupled directly with an alkyne via click chemistry, resulting into a paramagnetic and luminescent gadolinium(III complex. Luminescent data and relaxometric properties of the complex have been evaluated, suggesting the potential applicability of the complexes as a bimodal contrast agent for magnetic resonance and optical imaging. The complex displays a bright emission at 523 nm with an absorption maximum of 507 nm and high quantum yields of up to 83% in water. The proton relaxivity of the complex measured at 310 K and at frequencies of 20 and 60 MHz had the values of 3.9 and 3.6 s−1·mM−1, respectively.

  8. Vitamin B12 Phosphate Conjugation and Its Effect on Binding to the Human B12 -Binding Proteins Intrinsic Factor and Haptocorrin.

    Science.gov (United States)

    Ó Proinsias, Keith; Ociepa, Michał; Pluta, Katarzyna; Chromiński, Mikołaj; Nexo, Ebba; Gryko, Dorota

    2016-06-01

    The binding of vitamin B12 derivatives to human B12 transporter proteins is strongly influenced by the type and site of modification of the cobalamin original structure. We have prepared the first cobalamin derivative modified at the phosphate moiety. The reaction conditions were fully optimized and its limitations examined. The resulting derivatives, particularly those bearing terminal alkyne and azide groups, were isolated and used in copper-catalyzed alkyne-azide cycloaddition reactions (CuAAC). Their sensitivity towards light revealed their potential as photocleavable molecules. The binding abilities of selected derivatives were examined and compared with cyanocobalamin. The interaction of the alkylated derivatives with haptocorrin was less affected than the interaction with intrinsic factor. Furthermore, the configuration of the phosphate moiety was irrelevant to the binding process. PMID:27120016

  9. Patterned porous silicon photonic crystals with modular surface chemistry for spatial control of neural stem cell differentiation

    Science.gov (United States)

    Huang, Tiffany H.; Pei, Yi; Zhang, Douglas; Li, Yanfen; Kilian, Kristopher A.

    2016-05-01

    We present a strategy to spatially define regions of gold and nanostructured silicon photonics, each with materials-specific surface chemistry, for azide-alkyne cycloaddition of different bioactive peptides. Neural stem cells are spatially directed to undergo neurogenesis and astrogenesis as a function of both surface properties and peptide identity.We present a strategy to spatially define regions of gold and nanostructured silicon photonics, each with materials-specific surface chemistry, for azide-alkyne cycloaddition of different bioactive peptides. Neural stem cells are spatially directed to undergo neurogenesis and astrogenesis as a function of both surface properties and peptide identity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08327c

  10. Efficiency and effectiveness of physical and chemical mutagens and their combination in inducing chlorophyll mutations in M2 generation of Lablab [Lablab purpureus (l.) Sweet var. Typicus

    OpenAIRE

    T. Raja Srinivas* and P. Veerabadhiran

    2010-01-01

    A comparative study of the frequency and spectrum of chlorophyll mutations induced by gamma rays (150, 200, 250, 300 and350 Gy), sodium azide (0.5, 1.0, 1.5 and 2.0 mM) and combination treatments of gamma rays and sodium azide (100 Gy + 1.5mM, 150 Gy + 1.5 mM, 200 Gy + 1.0 mM, 250 Gy + 1.0 mM and 300 Gy + 0.5 mM) in M2 generationA was made in thelablab var. CO 9. Four different types of chlorophyll mutants viz., albina, viridis, chlorina and xantha were identified in thetreated population and...

  11. Differential role for ERK2 in anoxia-induced activation of transcription and translation of Hsp70 in NIH 3T3 cells

    DEFF Research Database (Denmark)

    Ossum, Carlo G; Lauritsen, Anders N; Karottki, Dorina Gabriela; Hoffmann, Else K

    2011-01-01

    transcription and translation of Hsp70 during recovery from chemical anoxia and the role of the extracellular signal regulated kinase ERK2 in this induction of Hsp70. 10 mM azide for 30 minutes (chemical anoxia) significantly inhibited the activity of ERK2 (measured as phospho-ERK) but the ERK-2 activity is...... rapidly increased in a MEK-independen manner, when azide is washed out of the cells. Chemical anoxia and overnight recovery induced Hsp70 expression (analyzed by Western blotting) and this was inhibited by actinomycin D as well as by cycloheximide showing that induction of both translation and...... transcription was involved. Inhibition of the MAP kinase p38, which was transiently activated during chemical anoxia, had no effect on the increase in Hsp70 expression whereas an inhibitor of reactive oxygen species and inhibition of the phosphatase PP1 and PP2a inhibited the increase in Hsp70 expression...

  12. Regulation of the mitogen-activated protein kinase p44 ERK activity during anoxia/recovery in rainbow trout hypodermal fibroblasts

    DEFF Research Database (Denmark)

    Ossum, Carlo G; Wulff, Tune; Hoffmann, Else K

    It is well known from various mammalian cells that anoxia has a major impact on the mitogen-activated protein kinase ERK, but a possible similar effect in fish cells has not been investigated. Here we characterise a p44ERK-like protein in the rainbow trout cell line RTHDF and study the effect of (i......) serum stimulation, (ii) sodium azide (chemical anoxia) and removal of azide (recovery) and (iii) anoxia (P(O)2<0.1%) and recovery. During both chemical and true anoxia p44ERK was inhibited and recovery resulted in robust reactivation of p44ERK activity, far above the initial level. The inhibition was...... secondary to activation of p38(MAPK) and the increase was MEK dependent, as SB203580 inhibited the dephosphorylation during anoxia and the presence of PD98059 inhibited phosphorylation of p44ERK during recovery. In addition, we demonstrated that the reactivation of p44ERK during recovery also was dependent...

  13. Sequestering survivin to functionalized nanoparticles: a strategy to enhance apoptosis in cancer cells.

    Science.gov (United States)

    Jenkins, Ragini; Bandera, Yuriy P; Daniele, Michael A; Ledford, LeAnna L; Tietje, Ashlee; Kelso, Andrew A; Sehorn, Michael G; Wei, Yanzhang; Chakrabarti, Mrinmay; Ray, Swapan K; Foulger, Stephen H

    2016-04-01

    Survivin belongs to the family of inhibitor of apoptosis proteins (IAP) and is present in most cancers while being below detection limits in most terminally differentiated adult tissues, making it an attractive protein to target for diagnostic and, potentially, therapeutic roles. Sub-100 nm poly(propargyl acrylate) (PA) particles were surface modified through the copper-catalyzed azide/alkyne cycloaddition of an azide-terminated survivin ligand derivative (azTM) originally proposed by Abbott Laboratories and speculated to bind directly to survivin (protein) at its dimer interface. Using affinity pull-down studies, it was determined that the PA/azTM nanoparticles selectively bind survivin and the particles can enhance apoptotic cell death in glioblastoma cell lines and other survivin over-expressing cell lines such as A549 and MCF7 relative to cells incubated with the original Abbott-derived small molecule inhibitor. PMID:26845086

  14. Cage-like bifunctional chelators, copper-64 radiopharmaceuticals and PET imaging using the same

    Energy Technology Data Exchange (ETDEWEB)

    Conti, Peter S.; Cai, Hancheng; Li, Zibo; Liu, Shuanglong

    2016-08-02

    Disclosed is a class of versatile Sarcophagine based bifunctional chelators (BFCs) containing a hexa-aza cage for labeling with metals having either imaging, therapeutic or contrast applications radiolabeling and one or more linkers (A) and (B). The compounds have the general formula ##STR00001## where A is a functional group selected from group consisting of an amine, a carboxylic acid, an ester, a carbonyl, a thiol, an azide and an alkene, and B is a functional group selected from the group consisting of hydrogen, an amine, a carboxylic acid, and ester, a carbonyl, a thiol, an azide and an alkene. Also disclosed are conjugate of the BFC and a targeting moiety, which may be a peptide or antibody. Also disclosed are metal complexes of the BFC/targeting moiety conjugates that are useful as radiopharmaceuticals, imaging agents or contrast agents.

  15. MOVPE of AlN and GaN by using novel precursors

    Science.gov (United States)

    Ho, Kwok-Lun; Jensen, Klavs F.; Hwang, Jen-Wei; Gladfelter, Wayne L.; Evans, John F.

    1991-01-01

    The technique of low pressure MOVPE has been used to grow thin films of AlN and GaN on silicon and (0001) sapphire substrates using the single-source precursors diethylaluminum azide [Et 2AlN 3] 3 (DEAA) and diethygallium azide [Et 2GaN 3] 3 (DEGA). In-situ growth rate measurements have been performed for AlN growth on Si substrates. For comparison with conventional MOVPE growth, epitaxial films of Al xGa 1- xN have also been deposited from triethylgallium (TEG), triethylaluminum (TEAl) and NH 3 under similar conditions. The properties of the grown films are discussed in terms of precursor selection and growth conditions.

  16. MOVPE of AlN and GaN by using novel precursors

    Energy Technology Data Exchange (ETDEWEB)

    Ho Kwoklun; Jensen, K.F. (Dept. of Chemical Engineering, Massachusetts Inst. of Tech., Cambridge (USA)); Hwang Jenwei; Gladfelter, W.L.; Evans, J.F. (Dept. of Chemistry, Univ. of Minnesota, Minneapolis (USA))

    1991-01-01

    The technique of low pressure MOVPE has been used to grow thin films of AlN and GaN on silicon and (0001) sapphire substrates using the single-source precursors diethylaluminum azide (Et{sub 2}AlN{sub 3}){sub 3} (DEAA) and diethylgallium azide (Et{sub 2}GaN{sub 3}){sub 3} (DEGA). In-situ growth rate measurements have been performed for AlN growth on Si substrates. For comparison with conventional MOVPE growth, epitaxial films of Al{sub x}Ga{sub 1-x}N have also been deposited from triethylgallium (TEG), triethylaluminum (TEAl) and NH{sub 3} under similar conditions. The properties of the grown films are discussed in terms of precursor selection and growth conditions. (orig.).

  17. Active oxygen species and a degree of UV-modification of structural and functional properties of lactate dehydrogenase

    International Nuclear Information System (INIS)

    The spectrophotometry and photofluorescence techniques were used in the studies on photochemical transformations of lactate dehydrogenase exposed to UV-irradiation with a dose of 2.25 kJ/m2, in the native state and in the presence of exogenous modifiers: sodium azide, β-carotene, histidine, D-mannitol, and tret-butanol. It was shown that UV-irradiation of the mixtures of lactate dehydrogenase with sodium azide, β-carotene and histidine results in restoration (by 99, 65 and 63 %, respectively) of the level of catalytic activity of the enzyme as compared to that observed after irradiating in the absence of the protectors. The protective effect provided by mannitol during UV-irradiation of the lactate dehydrogenase was 23 %. Thus, it was shown that active oxygen species - singlet molecular oxygen and hydroxyl radical - make significant contributions to photomodification of lactate dehydrogenase. (author)

  18. Demonstration of a sucrose-derived contrast agent for magnetic resonance imaging of the GI tract.

    Science.gov (United States)

    Martinez, Gary V; Navath, Suryakiran; Sewda, Kamini; Rao, Venkataramanarao; Foroutan, Parastou; Alleti, Ramesh; Moberg, Valerie E; Ahad, Ali M; Coppola, Domenico; Lloyd, Mark C; Gillies, Robert J; Morse, David L; Mash, Eugene A

    2013-04-01

    A scaffold bearing eight terminal alkyne groups was synthesized from sucrose, and copies of an azide-terminated Gd-DOTA complex were attached via copper(I)-catalyzed azide-alkyne cycloaddition. The resulting contrast agent (CA) was administered by gavage to C3H mice. Passage of the CA through the gastrointestinal (GI) tract was followed by T1-weighted magnetic resonance imaging (MRI) over a period of 47h, by which time the CA had exited the GI tract. No evidence for leakage of the CA from the GI tract was observed. Thus, a new, orally administered CA for MRI of the GI tract has been developed and successfully demonstrated. PMID:23481651

  19. Energetic 2,2-Dimethyltriazanium Salts: A New Family of Nitrogen-Rich Hydrazine Derivatives.

    Science.gov (United States)

    Forquet, Valérian; Sabaté, Carlos Miró; Jacob, Guy; Guelou, Yann; Delalu, Henri; Darwich, Chaza

    2015-08-01

    Amination of 1,1-dimethylhydrazine with NH2 Cl or hydroxylamine-O-sulfonic acid yields 2,2-dimethyltriazanium (DMTZ) chloride (3) and sulphate (4), respectively. The DMTZ cation was paired with the nitrogen-rich anions 5-aminotetrazolate (5), 5-nitrotetrazolate (6), 5,5'-azobistetrazolate (7), and azide (8), yielding a new family of energetic salts. The synthesis was carried out by metathesis reactions of salts 3 or 4 and a suitable silver or barium salt. To minimize the risks involved when using heavy metal salts, we used electrodialysis for the synthesis of azide 8, which avoids the use of highly sensitive species. The DMTZ derivatives were characterized by IR and multinuclear NMR spectroscopy, elemental analysis, and X-ray diffraction. Thermal stabilities were measured using DSC analysis and their sensitivities towards classical stimuli were determined using standard tests. Lastly, the relationship between hydrogen bonding in the solid state and sensitivity is discussed. PMID:25975814

  20. A Platform for Functional Conductive Polymers

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hoffmann, Christian; Lind, Johan Ulrik;

    Conductive polymers have been studied extensively during recent years. In order to broaden the application field of conductive polymers different methods have been tested and recently an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3) was developed(1, 2). The azide functional...... conductive polymer can be postpolymerization functionalized to introduce a large number of functionalities through click chemistry(3). Through selection of reaction conditions it is possible control the depth of the reaction into the polymer film to the upper surface or the entire film(4). Thus a conductive...... polymer can be prepared with a subsurface layer of highly conductive polymer where only the upper surface has been grafted with functional groups to ensure selectivity of the surface layer for e.g. interaction with specific biospecies. The conductive polymer can be patterned using selective etching, which...

  1. Staudinger ligation as a method for bioconjugation.

    Science.gov (United States)

    van Berkel, Sander S; van Eldijk, Mark B; van Hest, Jan C M

    2011-09-12

    In 1919 the German chemist Hermann Staudinger was the first to describe the reaction between an azide and a phosphine. It was not until recently, however, that Bertozzi and co-workers recognized the potential of this reaction as a method for bioconjugation and transformed it into the so-called Staudinger ligation. The bio-orthogonal character of both the azide and the phosphine functions has resulted in the Staudinger ligation finding numerous applications in various complex biological systems. For example, the Staudinger ligation has been utilized to label glycans, lipids, DNA, and proteins. Moreover, the Staudinger ligation has been used as a synthetic method to construct glycopeptides, microarrays, and functional biopolymers. In the emerging field of bio-orthogonal ligation strategies, the Staudinger ligation has set a high standard to which most of the new techniques are often compared. This Review summarizes recent developments and new applications of the Staudinger ligation. PMID:21887733

  2. Rhizobium japonicum mutants induced by gamma rays and some chemical mutagens

    International Nuclear Information System (INIS)

    Numerous symbiotic mutants of R.japonicum were isolated after UV irradiation or nitrosoguanidine mutagensis. Cultures of R.japonicum GM 377 were irradiated with 0, 25, 50, 75, 100, 150, 175, 200, 250 and 300 krad of gamma-rays. As for chemical mutagensis, cultures were treated with Sodium azide and colchicin at concentration of 1x10-6, 1x10-5, 5x10-5, 1x10-4, 5x10-4, 1x10-3 and 5x10-3 mol. Results revealed that gentamicin at concentration of 24.0 Mg/ml was able to kill all the populations of R.japonicum. Therefore, this concentration was used for mutants selection. However, numerous mutants at different freguencies were identified. The highest percentage of mutant was obtained with Sodium azide at 1x10-4 mol

  3. Selective Functionalization of Independently Addressed Microelectrodes by Electrochemical Activation and Deactivation of a Coupling Catalyst

    OpenAIRE

    Devaraj, Neal. K.; Dinolfo, Peter H.; Chidsey, Christopher E. D.; Collman, James P.

    2006-01-01

    We demonstrate selective functionalization of independently addressed microelectrodes by electrochemical activation and deactivation of a coupling catalyst. 1,2,3-Triazole formation between terminal acetylenes and organic azides is efficiently catalyzed by copper(I) complexes (a Sharpless “click” reaction) while the oxidized copper (II) complexes are inactive. By electrochemically activating or deactivating the catalyst by switching its redox state, we demonstrate control over triazole format...

  4. Photodynamic inactivation of in vitro bacterial cultures from pressure ulcers Inativação fotodinâmica de culturas de bactérias in vitro provenientes de úlceras de pressão

    OpenAIRE

    Paulo de Tarso Camillo de Carvalho; Ana Paula da Costa Marques; Felipe Abdalla dos Reis; Ana Carulina Guimarães Belchior; Iandara Schettert Silva; Carlos Alexandre Habitante; Daniela Aparecida Sussai

    2006-01-01

    PURPOSE: To evaluate in vitro the antibacterial effect of diode laser light of wavelength 650 nm, in association with the photosensitive substance toluidine blue, on the bacteria in infected skin ulcers. METHODS: Samples were collected by means of swabs containing a medium for transporting infected material from skin ulcers. The material was inoculated into culturing medium containing azide blood agar for the growth of Gram-positive bacteria, and MacConkey agar for Gram-negative bacteria, and...

  5. A simple method for enhancing the bioorthogonality of cyclooctyne reagent.

    Science.gov (United States)

    Tian, He; Sakmar, Thomas P; Huber, Thomas

    2016-04-01

    The cross-reactivity between some cyclooctynes and thiols limits the bioorthogonality of the strain-promoted azide-alkyne cycloaddition reaction. We show that a low concentration of β-mercaptoethanol significantly reduces the undesirable side reaction between bicyclononyne (BCN) and cysteine and while preserving free cysteines. We site-specifically label a genetically-encoded azido group in the visual photoreceptor rhodopsin to demonstrate the utility of the strategy. PMID:27009873

  6. Chemical modification of viscose fibres by adsorption of carboxymethyl cellulose and click chemistry

    OpenAIRE

    Anufrijeva, Olga

    2014-01-01

    Functionalization of cellulosic materials to achieve new and advanced properties is a widely explored research area. This thesis is focused on the novel approach for modification of cellulosic materials by the combination of adsorption of carboxymethyl cellulose (CMC) onto cellulose surface and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) “click” reaction. The literature part gives an overview on the basics of cellulose chemistry, chemical functionalization of cellulose, as wel...

  7. Non-Specific Inhibition of Ischemia- and Acidosis-Induced Intracellular Calcium Elevations and Membrane Currents by α-Phenyl-N-tert-butylnitrone, Butylated Hydroxytoluene and Trolox

    OpenAIRE

    Christopher Katnik; Javier Cuevas

    2014-01-01

    Ischemia, and subsequent acidosis, induces neuronal death following brain injury. Oxidative stress is believed to be a key component of this neuronal degeneration. Acute chemical ischemia (azide in the absence of external glucose) and acidosis (external media buffered to pH 6.0) produce increases in intracellular calcium concentration ([Ca2+] i ) and inward membrane currents in cultured rat cortical neurons. Two α-tocopherol analogues, trolox and butylated hydroxytoluene (BHT), and the spin t...

  8. 5,5′-(Butane-1,4-diylbis(1H-tetrazole dihydrate

    Directory of Open Access Journals (Sweden)

    Jian-Hua Xin

    2010-12-01

    Full Text Available The title compound, C6H10N8·2H2O, was prepared by the reaction of hexanedinitrile and sodium azide. The di-1H-tetrazole molecule lies on a crystallographic centre of inversion and is linked to the water molecules by N—H...O and O—H...N hydrogen bonds, forming a two-dimensional supramolecular structure in the crystal.

  9. PHOSPHORUS PENTOXIDE-METHANESULFONIC ACID CATALYZED EFFICIENT SYNTHESIS OF 5-SUBSTITUTED 1H-TETRAZOLE DERIVATIVES Phosphorpentoxid-Methansulfonsäure KATALYSIERTEN EFFICIENT Synthese von 5-substituierten 1H-Tetrazolderivate

    OpenAIRE

    Amulrao U. Borse,Mahesh N. Patil, Nilesh L. Patil, and Sandesh R. Tetgure

    2012-01-01

    The mixture of phosphorus pentoxide-methanesulfonic acid (Eaton’s reagent) is prove to be an efficient protocol for the [3+2] cycloaddition reaction between sodium azide and organic nitriles to give the corresponding 5-substituted 1H-tetrazole derivatives in good to excellent yields. The in situ formation of hydrazoic acid helps for the [3+2] cycloaddition reaction providing 5- substituted 1H-tetrazole with short reaction time.

  10. PHOSPHORUS PENTOXIDE-METHANESULFONIC ACID CATALYZED EFFICIENT SYNTHESIS OF 5-SUBSTITUTED 1H-TETRAZOLE DERIVATIVES Phosphorpentoxid-Methansulfonsäure KATALYSIERTEN EFFICIENT Synthese von 5-substituierten 1H-Tetrazolderivate

    Directory of Open Access Journals (Sweden)

    Amulrao U. Borse,Mahesh N. Patil, Nilesh L. Patil, and Sandesh R. Tetgure

    2012-07-01

    Full Text Available The mixture of phosphorus pentoxide-methanesulfonic acid (Eaton’s reagent is prove to be an efficient protocol for the [3+2] cycloaddition reaction between sodium azide and organic nitriles to give the corresponding 5-substituted 1H-tetrazole derivatives in good to excellent yields. The in situ formation of hydrazoic acid helps for the [3+2] cycloaddition reaction providing 5- substituted 1H-tetrazole with short reaction time.

  11. Design and Investigation of Novel Porphyrin(oid) Conjugate Systems

    OpenAIRE

    Biedermann, Miriam

    2013-01-01

    Within the first part of this thesis novel water-soluble donor-acceptor arrays built up by porphyrins and pyrene or perylene derivatives were designed via a copper(I)-catalysed 1,3-dipolar azide-alkyne cycloaddition reaction. For this purpose, suitable precursors, which were available by well-established synthetic literature procedures, were combined with newly developed complementary “click” counterparts. Thus, also the substance library of ortho-benzylic functionalised tetraarylporphyrins w...

  12. Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

    Directory of Open Access Journals (Sweden)

    Camilla Matassini

    2015-12-01

    Full Text Available The synthesis of new multivalent architectures based on a trihydroxypiperidine α-fucosidase inhibitor is reported herein. Tetravalent and nonavalent dendrimers were obtained by means of the click chemistry approach involving the copper azide-alkyne-catalyzed cycloaddition (CuAAC between suitable scaffolds bearing terminal alkyne moieties and an azido-functionalized piperidine as the bioactive moiety. A preliminary biological investigation is also reported towards commercially available and human glycosidases.

  13. Impact of bacterial and fungal processes on 14C-hexadecane mineralisation in weathered hydrocarbon contaminated soil

    International Nuclear Information System (INIS)

    In this study, the impact of bacterial and fungal processes on 14C-hexadecane mineralisation was investigated in weathered hydrocarbon contaminated soil. The extent of 14C-hexadecane mineralisation varied depending on the bioremediation strategy employed. Under enhanced natural attenuation conditions, 14C-hexadecane mineralisation after 98 days was 8.5 ± 3.7% compared to 14C-hexadecane mineralisation was further enhanced through Tween 80 amendments (28.9 ± 2.4%) which also promoted the growth of a Phanerochaete chyrsosporium fungal mat. Although fungal growth in weathered hydrocarbon contaminated soil could be promoted through supplementing additional carbon sources (Tween 80, sawdust, compost, pea straw), fungal 14C-hexadecane mineralisation was negligible when sodium azide was added to soil microcosms to inhibit bacterial activity. In contrast, when fungal activity was inhibited through nystatin additions, 14C-hexadecane mineralisation ranged from 6.5 ± 0.2 to 35.8 ± 3.8% after 98 days depending on the supplied amendment. Bacteria inhibition with sodium azide resulted in a reduction in bacterial diversity (33–37%) compared to microcosms supplemented with nystatin or microcosms without inhibitory supplements. However, alkB bacterial groups were undetected in sodium azide supplemented microcosms, highlighting the important role of this bacterial group in 14C-hexadecane mineralisation. - Highlights: ► The roles of different microbial groups in hydrocarbon mineralisation was assessed. ► Inhibiting fungal growth did not affect 14C-hexadecane mineralisation. ► Inhibiting bacterial growth resulted in negligible 14C-hexadecane mineralisation. ► alkB bacterial groups were undetected in sodium azide supplemented microcosms. ► The importance of alkB groups in 14C-hexadecane mineralisation was highlighted.

  14. Low-cost Adsorbents for the Removal of Mercury (11) from Aqueous Solution-A Comparative Study

    OpenAIRE

    Ajay Kumar Meena,; Mishra, G. K.; Satish Kumar; Chitra Rajagopal; P.N. Nagar

    2004-01-01

    The establishments of the Ministry of Defence, specifically ordnance factories and public sector undertakings (like Bharat Electronics Ltd), carry out operations like electroplating, metal1surface finishing, solid-state wafer processing, and initiatory manufacturing (lead azide, mercury fulminate), which generate waste water contaminated with hazardous heavy metals. Mercuryand its compounds are known to be highly toxic, both for the living organisms and theenvironment. To protect public healt...

  15. Copper Granule-Catalyzed Microwave-Assisted Click Synthesis of Polyphenol Dendrimers

    OpenAIRE

    Lee, Choon Young; Held, Rich; Sharma, Ajit; Baral, Rom; Nanah, Cyprien; Dumas, Dan; Jenkins, Shannon; Upadhaya, Samik; Du, Wenjun

    2013-01-01

    Syringaldehyde and vanillin-based antioxidant dendrimers were synthesized via microwave-assisted alkyne-azide 1,3-dipolar cycloaddition using copper granules as a catalyst. The use of Cu(I) as a catalyst resulted in copper contaminated dendrimers. In order to produce copper-free antioxidant dendrimers for biological applications, Cu(I) was substituted with copper granules. Copper granules were ineffective at both room temperature and under reflux conditions (< 5% yield). However, it was an ex...

  16. Synthesis of Novel Aliphatic N-sulfonylamidino Thymine Derivatives by Cu(I)-catalyzed Three-component Coupling Reaction

    OpenAIRE

    Krstulović, Luka; Ismaili, Hamit; Višnjevac, Aleksandar; Glavaš-Obrovac, Ljubica; Žinić, Biserka

    2012-01-01

    A series of new aliphatic N-sulfonylamidino thymine derivatives containing nucleobase, N-sulfonyl and amidine pharmacophores in the structure were synthesized by Cu(I)-catalyzed threecomponent coupling of 1-propargyl thymine, benzenesulfonyl azides and amines or ammonium salts. Preliminary in vitro antitumor screening (human cervix adenocarcinoma -HeLa and leukemia cells - Jurkat) revealed promising activities of N,N-diethyl- (2) and N-4-cyanobenzyl- (6) derivatives of 4-acetamido...

  17. Cytocompatible Poly(ethylene glycol)-co-polycarbonate Hydrogels Crosslinked by Copper-free, Strain-promoted “Click” Chemistry

    OpenAIRE

    Xu, Jianwen; Filion, Tera M.; Prifti, Fioleda; Song, Jie

    2011-01-01

    Strategies to encapsulate cells in cytocompatible 3-dimensional hydrogels with tunable mechanical properties and degradability without harmful gelling conditions are highly desired for regenerative medicine applications. Here we reported a method for preparing poly(ethylene glycol)-co-polycarbonate hydrogels through copper-free, strain-promoted azide-alkyne cycloaddition (SPAAC) “Click” chemistry. Hydrogels with varying mechanical properties were formed by “clicking” azido-functionalized poly...

  18. Early events in herpes simplex virus type 1 infection: photosensitivity of fluorescein isothiocyanate-treated virions.

    OpenAIRE

    DeLuca, N; Bzik, D; Person, S; Snipes, W

    1981-01-01

    Herpes simplex virus type 1 is photosensitized by treatment with fluorescein isothiocyante (FITC). The inactivation of FITC-treated virions upon subsequent exposure to light is inhibited by the presence of sodium azide, suggesting the involvement of singlet oxygen in the process. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed that treatment with FITC plus light induces crosslinks in viral envelope glycoproteins. Treatment of virions with high concentrations of FITC (50 mic...

  19. Fluorescent cellulose nanocrystals via supramolecular assembly of terpyridine-modified cellulose nanocrystals and terpyridine-modified perylene

    International Nuclear Information System (INIS)

    Highlights: ► Surfaces of cellulose nanocrystals were modified with terpyridine ligands. ► Fluorescent nanocrystals could be obtained via self-assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals. ► Further self-assembly of azide-functionalized terpyridine onto the fluorescent cellulose nanocrystals was possible to obtain nanocellulosic material with expected use in bioimaging. - Abstract: Due to their natural origin, biocompatibility, and non-toxicity, cellulose nanocrystals are promising candidates for applications in nanomedicine. Highly fluorescent nanocellulosic material was prepared via surface modification of cellulose nanocrystals with 2,2′:6′,2″-terpyridine side chains followed by supramolecular assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals (CTP) via RuIII/RuII reduction. The prepared terpyridine-modified cellulose-RuII-terpyridine-modified perylene (CTP-RuII-PeryTP) fluorescent nanocrystals were characterized using cross-polarized/magic angle spin 13C nuclear magnetic resonance (CP/MAS 13C NMR), Fourier transform infrared (FTIR), UV–visible, and fluorescence spectroscopy. In addition, further self-assembly of terpyridine units with azide functional groups onto CTP-RuII-PeryTP was possible via repeating the RuIII/RuII reduction protocol to prepare supramolecular fluorescent nanocrystals with azide functionality (CTP-RuII-PeryTP-RuII-AZTP). The prepared derivative may have potential application in bio-imaging since the terminal azide groups can be easily reacted with antigens via “Click” chemistry reaction.

  20. Određivanje aktivnosti sukcinat-dehidrogenaze in situ u soju kvasca Saccharomyces cerevisiae reakcijom s plavom tetrazolijevom soli

    OpenAIRE

    Kregiel, Dorota; Berlowska, Joanna; Ambroziak, Wojciech

    2008-01-01

    U ovom je istraživanju razvijen spektrofotometrijski postupak određivanja aktivnosti sukcinat-dehidrogenaze u soju Saccharomyces cerevisiae osjetljivom na azid. Propusnost stanica kvasca za 0,05 %-tni digitonin omogućila je ispitivanje enzimske aktivnosti toga soja in situ. U prisutnosti fenazin-metosulfata (kao prijenosnika elektrona) i natrijeva azida (koji inhibira enzim citokrom-oksidazu) došlo je do redukcije plave tetrazolijeve soli u plavi tetrazolijev formazan. Optimirani su razni fak...

  1. Maleimide-functionalized closo-dodecaborate albumin conjugates (MID-AC): Unique ligation at cysteine and lysine residues enables efficient boron delivery to tumor for neutron capture therapy.

    Science.gov (United States)

    Kikuchi, Shunsuke; Kanoh, Daisuke; Sato, Shinichi; Sakurai, Yoshinori; Suzuki, Minoru; Nakamura, Hiroyuki

    2016-09-10

    Maleimide-conjugating closo-dodecaborate sodium form 5c (MID) synthesized by the nucleophilic ring-opening reaction of closo-dodecaborate-1,4-dioxane complex 2 with tetrabutylammonium (TBA) azide was found to conjugate to free SH of cysteine and lysine residues in BSA under physiological conditions, forming highly boronated BSA that showed high and selective accumulation in tumor and significant tumor growth inhibition in colon 26 tumor-bearing mice subjected to thermal neutron irradiation. PMID:27422608

  2. Cycloalkenyl macromonomers from new multifunctional inimers : a platform for graft, bottle-brush and mikto-arm star copolymers

    OpenAIRE

    Nguyen, Duc Anh

    2016-01-01

    The objective of the present thesis was the preparation of complex macromolecules by the combination of controlled/livingpolymerization methods such as ring-opening (metathesis) polymerization (RO(M)P) and highly efficient orthogonal chemistries: copper-catalyzed azide-alkyne coupling (CuAAC) and thiol-ene reactions.In the first part of this work, a series of well-defined structural (co)polymers containing a cycloolefin (norbornene (NB) oroxanorbornene (ONB)) functionality bearing two polymer...

  3. Diazidobis[4,4,5,5-tetramethyl-2-(1,3-thiazol-2-yl-2-imidazoline-1-oxyl 3-oxide-κ2N1,O3]nickel(II

    Directory of Open Access Journals (Sweden)

    Jiu Li Chang

    2010-11-01

    Full Text Available In the title compound, [Ni(N32(C10H14N3O2S2], the NiII atom lies on an inversion center and adopts a distorted trans-NiO2N4 octahedral geometry, coordinated by two N,O-bidentate 4,4,5,5-tetramethyl-2-(5-methylimidazol-4-yl-2-imidazoline-1-oxyl 3-oxide nitronyl nitroxide radical ligands and two monodentate azide anions.

  4. Tandem Cu-catalyzed ketenimine formation and intramolecular nucleophile capture: Synthesis of 1,2-dihydro-2-iminoquinolines from 1-(o-acetamidophenyl)propargyl alcohols

    OpenAIRE

    Gadi Ranjith Kumar; Yalla Kiran Kumar; Ruchir Kant; Maddi Sridhar Reddy

    2014-01-01

    The copper-catalyzed ketenimine formation reaction of 1-(o-acetamidophenyl)propargyl alcohols with various sulfonyl azides is found to undergo a concomitant intramolecular nucleophile attack to generate 1,2-dihydro-2-iminoquinolines after aromatization (via elimination of acetyl and hydroxy groups) and tautomerization. The reaction produces 4-substituted and 3,4-unsubstituted title compounds in moderate to good yields under mild reaction conditions.

  5. Tandem Cu-catalyzed ketenimine formation and intramolecular nucleophile capture: Synthesis of 1,2-dihydro-2-iminoquinolines from 1-(o-acetamidophenyl)propargyl alcohols

    OpenAIRE

    Kumar, Gadi Ranjith; Kumar, Yalla Kiran; Kant, Ruchir; Reddy, Maddi Sridhar

    2014-01-01

    The copper-catalyzed ketenimine formation reaction of 1-(o-acetamidophenyl)propargyl alcohols with various sulfonyl azides is found to undergo a concomitant intramolecular nucleophile attack to generate 1,2-dihydro-2-iminoquinolines after aromatization (via elimination of acetyl and hydroxy groups) and tautomerization. The reaction produces 4-substituted and 3,4-unsubstituted title compounds in moderate to good yields under mild reaction conditions.

  6. Application of 1,2,3-triazolylidenes as versatile NHC-type ligands: synthesis, properties, and application in catalysis and beyond

    OpenAIRE

    Donnelly, Kate F.; Petronilho, Ana; Albrecht, Martin

    2013-01-01

    Triazolylidenes have rapidly emerged as a powerful subclass of N-heterocyclic carbene ligands for transition metals. They are readily available through regioselective [2 + 3] cycloaddition of alkynes and azides and subsequent metallation according to procedures established for related carbenes. Due to their mesoionic character, triazolylidenes are stronger donors than Arduengo-type imidazol-2-ylidenes. Spurred by these attractive attributes and despite their only recent emergence, triazolylid...

  7. Biodegradation of Trichloroethylene in Continuous-Recycle Expanded-Bed Bioreactors

    OpenAIRE

    Phelps, T. J.; Niedzielski, J. J.; Schram, R M; Herbes, S. E.; White, D. C.

    1990-01-01

    Experimental bioreactors operated as recirculated closed systems were inoculated with bacterial cultures that utilized methane, propane, and tryptone-yeast extract as aerobic carbon and energy sources and degraded trichloroethylene (TCE). Up to 95% removal of TCE was observed after 5 days of incubation. Uninoculated bioreactors inhibited with 0.5% Formalin and 0.2% sodium azide retained greater than 95% of their TCE after 20 days. Each bioreactor consisted of an expanded-bed column through wh...

  8. Viricidal effect of polymorphonuclear leukocytes on human immunodeficiency virus-1. Role of the myeloperoxidase system.

    OpenAIRE

    Klebanoff, S J; Coombs, R W

    1992-01-01

    Myeloperoxidase (MPO), H2O2, and chloride form an antimicrobial system in neutrophilic polymorphonuclear leukocytes (PMN) effective against a variety of microorganisms. Normal human PMN, when stimulated with phorbol myristate acetate or opsonized zymosan, are viricidal to HIV-1. The viricidal effect was lost when chloride was replaced by sulfate and was inhibited by the peroxidase inhibitor azide and by catalase, but not by heated catalase or superoxide dismutase, implicating H2O2. Stimulated...

  9. Remote Activation of Host Cell DNA Synthesis in Uninfected Cells Signaled by Infected Cells in Advance of Virus Transmission

    OpenAIRE

    Schmidt, Nora; Hennig, Thomas; Remigiusz A Serwa; Marchetti, Magda; O'Hare, Peter

    2015-01-01

    ABSTRACT Viruses modulate cellular processes and metabolism in diverse ways, but these are almost universally studied in the infected cell itself. Here, we study spatial organization of DNA synthesis during multiround transmission of herpes simplex virus (HSV) using pulse-labeling with ethynyl nucleotides and cycloaddition of azide fluorophores. We report a hitherto unknown and unexpected outcome of virus-host interaction. Consistent with the current understanding of the single-step growth cy...

  10. Adhesion of Colletotrichum lindemuthianum Spores to Phaseolus vulgaris Hypocotyls and to Polystyrene

    OpenAIRE

    Young, David H.; Kauss, Heinrich

    1984-01-01

    Adhesion of Colletotrichum lindemuthianum spores to Phaseolus vulgaris hypocotyls and to polystyrene was inhibited by the respiratory inhibitors sodium azide and antimycin A, indicating a requirement for metabolic activity in adhesion. Various commercial proteins and Tween 80 also reduced adhesion to both surfaces. Binding was enhanced by the presence of salts: sodium, potassium, calcium, and magnesium chlorides were equally effective. The removal of surface wax from hypocotyls by chloroform ...

  11. Advances in the use of mutation induction for genetic improvement of barley and native grains in Peru

    International Nuclear Information System (INIS)

    Barley seeds of two varieties were treated with several doses of gamma rays and sodium azide. Seeds of a quinoa (Chenopodium) variety were treated with three doses of gamma rays. Yield trials were conducted also for doubled haploid lines of barley derived from earlier mutagenic treatments. Some promising new barley mutant lines were identified in the yield trials. The results from the Chenopodium trials facilitate the determination of the optimum dose of gamma rays for the PRQ-22 variety. (author)

  12. Synthesis studies on the Melodinus alkaloid meloscine

    OpenAIRE

    Feldman, Ken S.; Antoline, Joshua F.

    2013-01-01

    The pentacyclic Melodinus alkaloid (±)-meloscine was synthesized in 19 chemical steps from 2-bromobenzaldehyde through a route featuring an allenyl azide cyclization cascade to deliver the core azabicyclo[3.3.0]octane substructure. Peripheral functionalization of this core included a Tollens-type aldol condensation to set the quaternary center at C(20) and a diastereoselective ring closing metathesis to forge the tetrahydropyridine ring.

  13. SYNTHESIS OF POLY ( ETHER-URETHANE) CONTAINING PENDANT AMINO GROUP

    Institute of Scientific and Technical Information of China (English)

    WU Jinhuang; SUN Yanhui; FENG Xinde

    1989-01-01

    This paper is concerned with the synthesis of poly (ether-urethane) with pendant amino groups. The copolyether produced by ring opening copolymerization of tetrahydrofuran and epibromohydrin was treated with sodium azide in dimethylformamide to form azido substituted copolyether. The poly (ether-urethane) made from it was subjected to reduction reaction to convert azido group to amino group. The stress-strain behavior and dynamic-mechanical properties of poly (ether-urethane) containing pendant amino groups were studied.

  14. Mutational Changes In Delphinium malabaricum (Huth.) Munz.: A Potential Ornamental Plant

    OpenAIRE

    Kolar Firdose R.; Ghatge Swaroopa R.; Nimbalkar Mansingraj S.; Dixit Ghansham B.

    2015-01-01

    Mutation breeding is an established method used for crop improvement and has played a major role in the development of many new flower color/shape mutant cultivars in ornamentals. The present study is aimed at inducing mutations in Delphinium malabaricum using chemical mutagens ethyl methane sulfonate (EMS), sodium azide (SA) and physical mutagen (gamma rays). It was observed that D. malabaricum manifested specific reactions to the treatments with EMS, SA and gamma rays. Identification and se...

  15. Stealth Polymeric Vesicles via Metal-free Click Coupling

    OpenAIRE

    Isaacman, Michael J.; Corigliano, Eleonora M.; Theogarajan, Luke S.

    2013-01-01

    The strain-promoted azide-alkyne cycloaddition represents an optimal metal-free method for the modular coupling of amphiphilic polymer blocks. Hydrophilic poly(oxazoline) (PMOXA) or poly(ethyleneglycol) (PEG) A-blocks were coupled with a hydrophobic poly(siloxane) B-block to provide triblock copolymers capable of self-assembling into vesicular nanostructures. Stealth properties investigated via a complement activation assay revealed the superior in vitro stealth attributes of polymeric vesicl...

  16. Enhancement of TFO Triplex Formation by Conjugation with Pyrene via Click Chemistry.

    Science.gov (United States)

    Taniguchi, Yosuke; Tomizaki, Akira; Matsueda, Nozomu; Okamura, Hidenori; Sasaki, Shigeki

    2015-01-01

    This paper reports the preparation of 14-mer triplex-forming oligonucleotides (TFOs) containing a 2-O-methyl-1-β-phenyl-α-propargyl-ribose unit, which was conjugated with azide-modified molecules via a click reaction. Modification of these TFOs with pyrene assisted triplex formation, improving the stability of the triplex DNA and the anti-proliferative effects against A549 cells. PMID:26521856

  17. Click Chemistry-Mediated Nanosensors for Biochemical Assays

    OpenAIRE

    Chen, Yiping; Xianyu, Yunlei; Wu, Jing; Yin, Binfeng; Jiang, Xingyu

    2016-01-01

    Click chemistry combined with functional nanoparticles have drawn increasing attention in biochemical assays because they are promising in developing biosensors with effective signal transformation/amplification and straightforward signal readout for clinical diagnostic assays. In this review, we focus on the latest advances of biochemical assays based on Cu (I)-catalyzed 1, 3-dipolar cycloaddition of azides and alkynes (CuAAC)-mediated nanosensors, as well as the functionalization of nanopro...

  18. Functional Virus-Based Polymer-Protein Nanoparticles by Atom Transfer Radical Polymerization

    OpenAIRE

    Pokorski, Jonathan K.; Breitenkamp, Kurt; Finn, M. G.

    2011-01-01

    Viruses and virus-like particles (VLPs) are useful tools in biomedical research. Their defined structural attributes make them attractive platforms for engineered interactions over large molecular surface areas. In this report, we describe the use of VLPs as multivalent macroinitiators for atom transfer radical polymerization (ATRP). The introduction of chemically reactive monomers during polymerization provides a robust platform for post-synthetic modification via the copper-catalyzed azide-...

  19. Cyclooctyne-based reagents for uncatalyzed click chemistry: A computational survey

    OpenAIRE

    Chenoweth , Kimberly; Chenoweth, David; Goddard, William A. III

    2009-01-01

    With the goal of identifying alkyne-like reagents for use in click chemistry, but without Cu catalysts, we used B3LYP density function theory (DFT) to investigate the trends in activation barriers for the 1,3-dipolar cycloadditions of azides with various cyclooctyne, dibenzocyclooctyne, and azacyclooctyne compounds. Based on these trends, we find monobenzocyclooctyne-based reagents that are predicted to have dramatically improved reactivity over currently employed reagents.

  20. Fluorescent cellulose nanocrystals via supramolecular assembly of terpyridine-modified cellulose nanocrystals and terpyridine-modified perylene

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Mohammad L., E-mail: mlhassan2004@yahoo.com [Cellulose and Paper Department and Center of Excellence for Advanced Sciences, Advanced Materials and Nanotechnology Group, National Research Center, Dokki, Cairo 12622 (Egypt); Moorefield, Charles M.; Elbatal, Hany S. [Maurice Morton Institute for Polymer Science, University of Akron, Akron, OH 44325 (United States); Newkome, George R. [Maurice Morton Institute for Polymer Science, University of Akron, Akron, OH 44325 (United States); Departments of Polymer Science and Chemistry, University of Akron, Akron, OH 44325 (United States); Modarelli, David A.; Romano, Natalie C. [Department of Chemistry and The Center for Laser and Optical Spectroscopy, University of Akron, Akron, OH 44325 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Surfaces of cellulose nanocrystals were modified with terpyridine ligands. Black-Right-Pointing-Pointer Fluorescent nanocrystals could be obtained via self-assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals. Black-Right-Pointing-Pointer Further self-assembly of azide-functionalized terpyridine onto the fluorescent cellulose nanocrystals was possible to obtain nanocellulosic material with expected use in bioimaging. - Abstract: Due to their natural origin, biocompatibility, and non-toxicity, cellulose nanocrystals are promising candidates for applications in nanomedicine. Highly fluorescent nanocellulosic material was prepared via surface modification of cellulose nanocrystals with 2,2 Prime :6 Prime ,2 Double-Prime -terpyridine side chains followed by supramolecular assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals (CTP) via Ru{sup III}/Ru{sup II} reduction. The prepared terpyridine-modified cellulose-Ru{sup II}-terpyridine-modified perylene (CTP-Ru{sup II}-PeryTP) fluorescent nanocrystals were characterized using cross-polarized/magic angle spin {sup 13}C nuclear magnetic resonance (CP/MAS {sup 13}C NMR), Fourier transform infrared (FTIR), UV-visible, and fluorescence spectroscopy. In addition, further self-assembly of terpyridine units with azide functional groups onto CTP-Ru{sup II}-PeryTP was possible via repeating the Ru{sup III}/Ru{sup II} reduction protocol to prepare supramolecular fluorescent nanocrystals with azide functionality (CTP-Ru{sup II}-PeryTP-Ru{sup II}-AZTP). The prepared derivative may have potential application in bio-imaging since the terminal azide groups can be easily reacted with antigens via 'Click' chemistry reaction.

  1. Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

    Science.gov (United States)

    Matassini, Camilla; Mirabella, Stefania; Goti, Andrea; Robina, Inmaculada; Moreno-Vargas, Antonio J

    2015-01-01

    Summary The synthesis of new multivalent architectures based on a trihydroxypiperidine α-fucosidase inhibitor is reported herein. Tetravalent and nonavalent dendrimers were obtained by means of the click chemistry approach involving the copper azide-alkyne-catalyzed cycloaddition (CuAAC) between suitable scaffolds bearing terminal alkyne moieties and an azido-functionalized piperidine as the bioactive moiety. A preliminary biological investigation is also reported towards commercially available and human glycosidases. PMID:26734108

  2. Multicomponent analysis of fermentation growth media using the electronic tongue (ET)

    DEFF Research Database (Denmark)

    Legin, A.; Kirsanov, D.; Rudnitskaya, A.; Iversen, J.J.L.; Seleznev, B.; Esbensen, Kim Harry; Mortensen, J.; Houmøller, Lars Plejdrup; Vlasov, Yu.

    2004-01-01

    simultaneous determination of ammonium, citrate and oxalate in complex media with good precision (typical error within 8%). The system preserved high sensitivity to the targeted substances also in the presence of sodium azide, which is commonly used for suppressing microbial activity in real-world fermentation...... samples. Sensor performance was fast and reproducible which promises well for routine application of the electronic tongue for fermentation process monitoring....

  3. A one-pot radiosynthesis of [125I]iodoazido photoaffinity labels

    International Nuclear Information System (INIS)

    A useful method for preparing radioiodinated photoaffinity labels from alkyl anilines which offer significant advantages over present methods is described. The one-pot synthesis gives good radiochemical yields (40-64%) of pure, high specific activity (350-1500 mCi/μmol) 124I labelled iodaryl azides while minimising manipulation of radioactive materials. Purification of the [125I]iodoazido photoaffinity labels is achieved by high performance liquid chromatography. (author)

  4. A versatile and an efficient synthesis of 5-substituted-1-tetrazoles

    Indian Academy of Sciences (India)

    Madhusudana Reddy Muthukur Bhoje Gowd; Mohamed Afzal Pasha

    2011-01-01

    A simple, efficient and a versatile method for the synthesis of 5-substituted-1-tetrazoles by a [3+2]-cycloaddition reaction of arylnitriles with sodium azide in DMF using ZrOCl2·8 H2O as catalyst has been developed. The reactions work well at 100°C and give the desired products in excellent yield. The examples studied include arylnitriles having electron donating as well as electron releasing groups on the arene nucleus.

  5. Membrane Assembly Driven by a Biomimetic Coupling Reaction

    OpenAIRE

    Budin, Itay; Devaraj, Neal K.

    2011-01-01

    One of the major goals of synthetic biology is the development of non-natural cellular systems. In this work we describe a catalytic biomimetic coupling reaction capable of driving the de novo self-assembly of phospholipid membranes. Our system features a copper catalyzed azide-alkyne cycloaddition that results in the formation of a triazole containing phospholipid analog. Concomitant assembly of membranes occurs spontaneously, not requiring preexisting membranes to house catalysts or precurs...

  6. SYNTHESIS AND CHARACTERIZATION OF TRIAZOLE CONTAINING LIQUID CRYSTALLINE POLYMERS THROUGH 1,3-DIPOLAR CYCLOADDITION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Devamani; Srividhya; Sundaram; Manjunathan; Sivashankaran; Nithyanandan; Subramanan; Balamurugan; Sengodan; Senthil

    2009-01-01

    Liquid crystalline polymers containing 1,2,3-triazole units as linking groups have been synthesized from the monomers containing triad ester diazide and flexible dialkyne ester by 1,3-cycloaddition reaction and were characterized. Click reaction of azide and alkyne functionals catalyzed by Cu(I) yielded target polyesters with 1,2,3-triazole groups.The structure of the polymer was confirmed by spectral techniques.GPC analysis reveals that the polymers have moderate molecular weight with narrow distributio...

  7. Syntéza azidoanalog neuroaktivních steroidů

    Czech Academy of Sciences Publication Activity Database

    Černý, Ivan; Buděšínský, Miloš; Pouzar, Vladimír; Chodounská, Hana

    2010-01-01

    Roč. 104, č. 11 (2010), s. 1073-1073. ISSN 0009-2770. [Pokroky v organické, bioorganické a farmaceutické chemii /45./. 20.11.2010-22.11.2010, Nymburk] R&D Projects: GA MŠk(CZ) LC06077 Institutional research plan: CEZ:AV0Z40550506 Keywords : steroid * azide * synthesis Subject RIV: CC - Organic Chemistry

  8. Ultrasound-assisted synthesis of 1-N-{beta}-D-glucopyranosyl-1H-1,2,3-triazole benzoheterocycles and their anti-inflammatory activities

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gilson B. da; Guimaraes, Bruna M.; Oliveira, Ronaldo N. de, E-mail: ronaldonoliveira@dcm.ufrpe.br [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Departamento de Ciencias Moleculares; Assis, Shalom P.O.; Lima, Vera L.M. [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Departamento de Bioquimica. Laboratorio de Quimica e Metabolismo de Lipideos e Lipoproteinas

    2013-06-15

    In this work, the preparation of various glucosyl triazoles from a reaction between 2,3,4,6-tetra-O-acetyl-{beta}-D-glucopyranosyl azide and terminal alkynes was developed in moderate to excellent yields (63-99%). Ultrasound energy was applied at each step of the reaction to increase chemical reactivity. In addition, the compounds conjugated with benzoheterocycles moieties revealed potent anti-inflammatory activity. (author)

  9. 'Clickable' ZnO nanocrystals: the superiority of a novel organometallic approach over the inorganic sol-gel procedure.

    Science.gov (United States)

    Grala, Agnieszka; Wolska-Pietkiewicz, Małgorzata; Danowski, Wojciech; Wróbel, Zbigniew; Grzonka, Justyna; Lewiński, Janusz

    2016-05-31

    We demonstrate for the first time a highly efficient Cu(i)-catalyzed alkyne-azide cycloaddition reaction on the surface of ZnO nanocrystals with retention of their photoluminescence properties. Our comparative studies highlight the superiority of a novel self-supporting organometallic method for the preparation of brightly luminescent and well-passivated ZnO nanocrystals over the traditional sol-gel procedure. PMID:27156855

  10. Lewis acid Mediated Aza-Diels-Alder Reactions and Asymmetric Alkylations of 2H-azirines

    OpenAIRE

    Risberg, Erik

    2004-01-01

    This thesis describes the use of 2H-azirines, three-membered unsaturatednitrogen-containing heterocycles, as reactive intermediates ina number of Lewis acid promoted alkylations and Diels-Alderreactions providing synthetically useful aziridines. In order to carry out this investigation a new generalprocedure for the ring closure of vinyl azides, forming theresultant 3-substituted-2H-azirines, was developed applying low boiling solventsin closed reaction vessels at elevated temperatures. The a...

  11. In situ visualization of newly synthesized proteins in environmental microbes using amino acid tagging and click chemistry

    OpenAIRE

    Hatzenpichler, Roland; Scheller, Silvan; Tavormina, Patricia L.; Babin, Brett M; Tirrell, David A.; Orphan, Victoria J.

    2014-01-01

    Here we describe the application of a new click chemistry method for fluorescent tracking of protein synthesis in individual microorganisms within environmental samples. This technique, termed bioorthogonal non-canonical amino acid tagging (BONCAT), is based on the in vivo incorporation of the non-canonical amino acid L-azidohomoalanine (AHA), a surrogate for l -methionine, followed by fluorescent labelling of AHA-containing cellular proteins by azide-alkyne click chemistry. BONCAT was evalua...

  12. 無および低カタラーゼ血症マウスのカタラーゼ分子の性質に関する研究 第1編 マウス肝カタラーゼ活性に対する変性剤の影響

    OpenAIRE

    佐藤,征紀

    1985-01-01

    Homogenates of mouse liver with isotonic sucrose solution were separated by the cell fractionation with repeating centrifugation. The supernatants were used for the inhibition test with the reagents such as 3,5 diiodosalicylic acid lithium salt (LIS), guanidine and azide, heat, acid and alkali. After various treatments, the remaining catalase activities were measured and showed as a relative enzyme activity. Stability of catalase in liver supernatants was compared normal (C3H/C(as)C(as)) and ...

  13. Thermally induced structural transformation of polytriazoleimide to polyindoleimide

    Institute of Scientific and Technical Information of China (English)

    Yan Peng E; Li Qiang Wan; Yu Jing Li; Fa Rong Huang; Lei Du

    2012-01-01

    A new kind of polytriazoleimide containing bisphenyl-1,2,3-triazole (BPT) was synthesized by copper-catalyzed 1,3-dipolar cycloaddition of azides and alkynes (CuAAC) and polycondensation.The thermal stability and degradation mechanism of the polytriazoleimide were investigated.The results show that the structure of BPT in polytriazoleimide transforms to phenylindole after thermal treatment,accompanying the release of N2.

  14. An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

    OpenAIRE

    Quanxuan Zhang; Hong Ren; Baker, Gregory L.

    2014-01-01

    2-Hydroxy-4-pentynoic acid (1) is a key intermediate towards ‘clickable’ polylactide which allows for efficient introduction of a broad range of pendant functional groups onto polymers from a single monomer via convenient ‘click’ chemistry with organic azides. The incorporation of various pendant functional groups could effectively tailor the physicochemical properties of polylactide. The reported synthesis of 1 started from propargyl bromide and ethyl glyoxylate. However, both of starting ma...

  15. Synthesis of ferrocene-functionalized monomers for biodegradable polymer formation

    OpenAIRE

    Upton, BM; Gipson, RM; Duhović, S; Lydon, BR; Matsumoto, NM; Maynard, HD; Diaconescu, PL

    2014-01-01

    This journal is © the Partner Organisations 2014. Cyclic carbonate and δ-valerolactone substrates functionalized with ferrocene were synthesized via alkyne-azide "click" cycloaddition. The cyclic carbonates were polymerized using 1,8-diazabicycloundec-7-ene, 1-(3,5-bis(trifluoromethyl)phenyl)-3-cyclohexylthiourea, and benzyl alcohol. The resulting polymers were characterized by GPC, NMR spectroscopy, and cyclic voltammetry studies. It was found that polycarbonate molecular weights fall in the...

  16. Nitrene Metathesis and Catalytic Nitrene Transfer Promoted by Niobium Bis(imido) Complexes.

    Science.gov (United States)

    Kriegel, Benjamin M; Bergman, Robert G; Arnold, John

    2016-01-13

    We report a metathesis reaction in which a nitrene fragment from an isocyanide ligand is exchanged with a nitrene fragment of an imido ligand in a series of niobium bis(imido) complexes. One of these bis(imido) complexes also promotes nitrene transfer to catalytically generate asymmetric dialkylcarbodiimides from azides and isocyanides in a process involving the Nb(V)/Nb(III) redox couple. PMID:26698833

  17. Fabrication and Anti-Fouling Properties of Photochemically and Thermally Immobilized Poly(Ethylene Oxide) and Low Molecular Weight Poly(Ethylene Glycol) Thin Films

    OpenAIRE

    Wang, Hui; Ren, Jin; Hlaing, Aye; Yan, Mingdi

    2010-01-01

    Poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) were covalently immobilized on silicon wafers and gold films by way of the CH insertion reaction of perfluorophenyl azides (PFPAs) by either photolysis or thermolysis. The immobilization does not require chemical derivatization of PEO or PEG, and polymers of different molecular weights were successfully attached to the substrate to give uniform films. Microarrays were also generated by printing polymer solutions o...

  18. Polysaccharides: The “Click” Chemistry Impact

    OpenAIRE

    Romain Lucas; Daniel Montplaisir; Rachida Zerrouki; Pierre-Antoine Faugeras; François Brouillette; Benjamin Boëns; Pierre-Henri Elchinger

    2011-01-01

    Polysaccharides are complex but essential compounds utilized in many areas such as biomaterials, drug delivery, cosmetics, food chemistry or renewable energy. Modifications and functionalizations of such polymers are often necessary to achieve molecular structures of interest. In this area, the emergence of the “click” chemistry concept, and particularly the copper-catalyzed version of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides, had an impact on the ...

  19. Synthesis of N-substituted phthalimidoalkyl 1H-1,2,3-triazoles: a molecular diversity combining click chemistry and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Moara T. da; Oliveira, Ronaldo N. de; Valenca, Wagner O.; Barbosa, Fernanda C.G.; Silva, Mauro G. da; Camara, Celso A., E-mail: ronaldonoliveira@dcm.ufrpe.br [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Dept. de Ciencias Moleculares

    2012-10-15

    A series of 1,2,3-triazole derivatives was synthesized from N-phthalimidoalkyl-azides (A{sub 1}-A{sub 4}) and alkynes (a-e) under ultrasound irradiation in the presence of CuI, Et{sub 3}N and DMF as solvent. The present protocol afforded 18 new 1,2,3-triazoles (1-4) in good-to-excellent yields (67-98%). (author)

  20. Synthesis of N6-Substituted-2-Triazolyl-Adenine Derivatives

    OpenAIRE

    Novosjolova, I; Bizdēna, Ē; Beļakovs, S; Turks, M

    2013-01-01

    A novel class of 2,6-bis-triazolylpurine nucleosides were obtained from 2,6-diazido precursors via copper (I) catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction. These intermediates appeared to be very reactive towards N-nucleophiles and thus selectively gave C(6)-substituted analogs with triazolyl moiety at C(2)-position. Thereby, 1,2,3-triazoles act as good leaving groups in regioselective nucleophilic aromatic substitution reactions.

  1. 2,6-Diazidopurine Deoxyribo-Nucleoside as Substrate for the Click Reaction

    OpenAIRE

    Cīrule, D; Ozols, K; Bizdēna, Ē; Novosjolova, I

    2014-01-01

    The chemistry of triazolyl-substituted purine nucleosides is attractive since some of them exhibit antiviral, anticancer or fluorescent properties. Our group has reported the synthesis of 2,6-bistriazolyl purine arabino- and ribo-nucleosides using Cu(I) catalysed azide - alkyne 1,3-dipolar cycloaddition reaction. Various nucleophilic substitution reactions with the obtained products were carried out. In addition to our previous work, herein we report the synthesis of the novel...

  2. Synthesis of star and H-shape polymers via a combination of cobalt-mediated radical polymerization and nitrone-mediated radical coupling reactions

    OpenAIRE

    Detrembleur, Christophe; Debuigne, Antoine; Altintas, Ozcan; Conradi, Matthias; Wong, Edgar H. H.; Jerome, Christine; Barner-Kowollik, Christopher; Junkers, Thomas

    2012-01-01

    Via consecutive cobalt-mediated radical polymerization (CMRP), nitrone-mediated radical coupling (NMRC) and copper catalyzed azide-alkyne cycloaddition (CuAAC), polymers with mikto-arm star and H-shape architecture were synthesized. Poly(vinyl acetate)(40)-block-poly(acrylonitrile)(78)-Co(acac)(2) polymers were synthesized via CMRC and subsequently coupled using an alkyne functional nitrone. The coupling efficiency of the NMRC process was assessed employing N-tert-butyl alpha-phenyl nitrone (...

  3. Preparation of reactive fibre interfaces using multifunctional cellulose derivatives.

    Science.gov (United States)

    Vega, Beatriz; Wondraczek, Holger; Bretschneider, Leonore; Näreoja, Tuomas; Fardim, Pedro; Heinze, Thomas

    2015-11-01

    Cellulose fibres have poor reactivity and limited potential for surface engineering with advanced chemical functionalization in water. In this work, cellulose fibres were decorated with azide functions by charge-directed self-assembly of a novel water-soluble multifunctional cellulose derivative yielding reactive fibres. Propargylamine and 1-ethynylpyrene were utilized as a proof of concept that alkyne molecules may react with the azide functions of the reactive fibres via copper(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAc) reaction in mild conditions. Chemical characterization of the fibres was carried out using classical techniques such as Raman-, fluorescence-, and UV-vis spectroscopy. Among other techniques, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray spectroscopy (XPS), two-photon microscopy (TPM), and inductively coupled plasma mass spectrometry (ICP-MS) were useful tools for additional characterization of the fibres decorated with amino- or photoactive groups. The information gathered in this work might contribute to the basis for the preparation of reactive cellulose-based interfaces with potential application in CuAAc reactions. PMID:26256349

  4. Di-μ-azido-bis(μ-1,4,7,10,13,16-hexaoxacyclooctadecanebis(5,10,15,20-tetraphenylporphyrinatodicadmiumdisodium

    Directory of Open Access Journals (Sweden)

    Hamza Toumi

    2012-12-01

    Full Text Available The asymmetric unit of the title compound, [Cd2Na2(N32(C44H28N42(C12H24O62], consists of one half of the dimeric complex; the tetranuclear molecule lies about an inversion centre. The CdII atom is coordinated by the four pyrrole N atoms of the 5,10,15,20-tetraphenylporphyrinate ligand and one N atom of the axial azide ligand in a square-pyramidal geometry. The azide group is also linked to the NaI atom, which is surrounded by one 18-crown-6 molecule and additionally bonded to a second 18-crown-6 molecule trans to the azide group. The porphyrin core exhibits a major doming distortion (∼40% and the crystal structure is stabilized by weak C—H...π interactions. The molecular structure features weak intramolecular hydrogen bonds: two O—H...O interactions within the 18-crown-6 molecule and one C—H(18-crown-6...N(azido contact.

  5. The First Molybdenum(VI) and Tungsten(VI) Oxoazides MO2(N3)2, MO2(N3)2⋅2 CH3CN, (bipy)MO2(N3)2, and [MO2(N3)4](2-) (M=Mo, W).

    Science.gov (United States)

    Haiges, Ralf; Skotnitzki, Juri; Fang, Zongtang; Dixon, David A; Christe, Karl O

    2015-08-10

    Molybdenum(VI) and tungsten(VI) dioxodiazide, MO2(N3)2 (M=Mo, W), were prepared through fluoride-azide exchange reactions between MO2F2 and Me3SiN3 in SO2 solution. In acetonitrile solution, the fluoride-azide exchange resulted in the isolation of the adducts MO2(N3)2⋅2 CH3CN. The subsequent reaction of MO2(N3)2 with 2,2'-bipyridine (bipy) gave the bipyridine adducts (bipy)MO2(N3)2. The hydrolysis of (bipy)MoO2(N3)2 resulted in the formation and isolation of [(bipy)MoO2N3]2O. The tetraazido anions [MO2(N3)4](2-) were obtained by the reaction of MO2(N3)2 with two equivalents of ionic azide. Most molybdenum(VI) and tungsten(VI) dioxoazides were fully characterized by their vibrational spectra, impact, friction, and thermal sensitivity data and, in the case of (bipy)MoO2(N3)2, (bipy)WO2(N3)2, [PPh4]2[MoO2(N3)4], [PPh4]2[WO2(N3)4], and [(bipy)MoO2N3]2O by their X-ray crystal structures. PMID:26178877

  6. Lifetimes of -halo and -azidobenzyl carbocations in aqueous solution

    Indian Academy of Sciences (India)

    R Sanjeev; V Jagannadham

    2002-02-01

    The title cations were produced in aqueous solution by chemical initiation (solvolysis) of benzyl-gem-dihalides and benzyl-gem-diazides. The solvolysis reactions of benzyl-gem-dihalides and benzyl-gem-diazides in water proceed by a stepwise mechanism through -halobenzyl carbocation and -azidobenzyl carbocation intermediates, which are captured by water to give the corresponding carbonyl compounds as the sole detectable products. Rate constant ratio / (M-1) for partitioning of the carbocation between reaction with halide/azide ion and reaction with water is determined by analysis of halide/azide common ion inhibition of the solvolysis reaction. The rate constants (s-1) for the reaction of the cation with solvent water were determined from the experimental values of / and solv, for the solvolysis of the benzyl-gem-dihalides and benzyl-gem-diazides respectively, using = 5 × 109 M-1 s-1 for diffusion-limited reaction of halide/azide ion with -substituted benzyl carbocations. The values of 1/ are thus the lifetimes of the -halobenzyl carbocations and -azidobenzyl carbocations respectively.

  7. Two EE-azido-bridged nickel(II) layered compounds: vigorous twisted torsion angle Ni-N3-Ni results in ferromagnetic behavior.

    Science.gov (United States)

    Li, Ru-Yin; Wang, Bing-Wu; Wang, Xin-Yi; Wang, Xiu-Teng; Wang, Zhe-Ming; Gao, Song

    2009-08-01

    Two coordination polymers, Ni(endi)(N(3))(2) (endi = 1,2-bis(tetrazol-1-yl)ethane) (1) and Ni(4-acpy)(2)(N(3))(2) (4-acpy = 4-acetylpyridine) (2), are obtained by employing a couple of cobalt complex as references. Both compounds have similar 2D (4,4) EE azide-nickel layer structures, but different interlayer separations. Their EE azide bridges are vigorously twisted, with the torsion angle tau value 88.3 degrees and 107.6 degrees for 1 and 89.2 degrees for 2. Different from most EE azide compounds, ferromagnetism is distinctly present, ordering below T(c) = 25 K for 1 and T(c) = 23 K for 2. Fitting of magnetic susceptibility data using the spin Hamiltonian H = -2J SigmaS(1)S(2) gives the ferromagnetic intralayer coupling J = 14.70(6) cm(-1) for 1 and 14.32(0) cm(-1) for 2, respectively. The magnetostructural correlations of 1 have been calculated using the density function theory based method. The computational results are consistent with the trend of the experimental data. One possible mechanism was proposed to explain the emergence of ferromagnetism based on the theoretical studies, and the ferromagnet construction approach was also proposed accordingly. PMID:19569711

  8. Novel 1,3-dipolar cycloadditions of dinitraminic acid: implications for the chemical stability of ammonium dinitramide.

    Science.gov (United States)

    Rahm, Martin; Brinck, Tore

    2008-03-20

    Density functional theory at the B3LYP/6-31+G(d,p) level and ab initio calculations at the CBS-QB3 level have been used to analyze 1,3 dipolar cycloaddition reactions of dinitraminic acid (HDN) and its proton transfer isomer (HO(O)NNNO2). It is shown that the nitro group of HDN and the -N-N=O functionality of the isomer react readily with carbon-carbon double bonds. Cycloadditions of HDN are compared with the corresponding reactions with azides and nitrile oxides as 1,3 dipoles. It is shown that the reactivities of HDN and its proton transfer isomer decrease with increasing electron withdrawing power of the substituents adjacent to the carbon-carbon double bond. In contrast, for azides and nitrile oxides, the highest reactivity is obtained with dipolarophiles with strongly electron withdrawing substituents. The observed reactivity trends allow for the design of unsaturated compounds that are highly reactive toward azides and chemically inert toward dinitramides. This may be of relevance for the development of binder materials for ammonium dinitramide based propellants. PMID:18278886

  9. Synthesis and in vitro pharmacological evaluation of N-[(1-benzyl-1,2,3-triazol-4-yl)methyl]-carboxamides on d-secoestrone scaffolds.

    Science.gov (United States)

    Szabó, Johanna; Bacsa, Ildikó; Wölfling, János; Schneider, Gyula; Zupkó, István; Varga, Mónika; Herman, Bianka E; Kalmár, László; Szécsi, Mihály; Mernyák, Erzsébet

    2016-08-01

    An efficient synthesis of several N-[(1-benzyl-1,2,3-triazol-4-yl)methyl]carboxamides in the 13β- and 13α-d-secoestrone series is reported. Novel triazoles were synthesized via the Cu(I)-catalyzed azide-alkyne cycloaddition of steroidal alkynyl carboxamides and p-substituted benzyl azides. Each of the products was evaluated in vitro by means of MTT assays for antiproliferative activity against a panel of human adherent cancer cell lines (HeLa, MCF-7, A431 and A2780). Some of them exhibited activities similar to those of the reference agent cisplatin. On change of the substitution pattern of the benzyl group of the azide, great differences in the cell growth-inhibitory properties were observed. The p-alkylbenzyl-substituted triazoles selectively exerted high cytostatic action against A2780 cells, with IC50 values of 1 µM. We investigated the potential inhibitory action exerted on the human 17β-HSD1 activity of the new secosteroids. Three triazoles effectively suppressed the estrone to 17β-estradiol conversion with IC50 values in low micromolar range. PMID:26360618

  10. Efficiency and effectiveness of physical and chemical mutagens and their combination in inducing chlorophyll mutations in M2 generation of Lablab [Lablab purpureus (l. Sweet var. Typicus

    Directory of Open Access Journals (Sweden)

    T. Raja Srinivas* and P. Veerabadhiran

    2010-07-01

    Full Text Available A comparative study of the frequency and spectrum of chlorophyll mutations induced by gamma rays (150, 200, 250, 300 and350 Gy, sodium azide (0.5, 1.0, 1.5 and 2.0 mM and combination treatments of gamma rays and sodium azide (100 Gy + 1.5mM, 150 Gy + 1.5 mM, 200 Gy + 1.0 mM, 250 Gy + 1.0 mM and 300 Gy + 0.5 mM in M2 generationA was made in thelablab var. CO 9. Four different types of chlorophyll mutants viz., albina, viridis, chlorina and xantha were identified in thetreated population and mutation frequency was calculated on plant population basis. Frequency of chlorina mutants washighest followed by albina, xantha and viridis. Combination treatments in general proved to be very effective followed bysodium azide and gamma rays in inducing maximum frequency of chlorophyll mutations. Although the chlorophyll mutationsdo not have any economic value due to their lethal nature, such a study could be useful in identifying the threshold dose of amutagen that would increase the genetic variability and number of economically useful mutants in the segregating generations.

  11. Water-soluble PEGylated silicon nanoparticles and their assembly into swellable nanoparticle aggregates

    International Nuclear Information System (INIS)

    Water-soluble silicon nanoparticles were synthesized by grafting PEG polymers onto functionalized silicon nanoparticles with distal alkyne or azide moieties. The surface-functionalized silicon nanoparticles were produced in one step from the reactive high-energy ball milling (RHEBM) of silicon wafers with a mixture of either 5-chloro-1-pentyne in 1-pentyne or 1,7 octadiyne in 1-hexyne to afford air and water-stable chloroalkyl or alkynyl-terminated nanoparticles, respectively. Nanoparticles with the ω-chloroalkyl substituents were easily converted to ω-azidoalkyl groups through the reaction of the Si nanoparticles with sodium azide in DMF. The azido-terminated nanoparticles were then grafted with mono-alkynyl-PEG polymers using a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction to afford core–shell silicon nanoparticles with a covalently attached PEG shell. Covalently linked Si nanoparticle clusters were synthesized via the CuAAC “click” reaction of functional Si NPs with α,ω-functional PEG polymers of various lengths. Dynamic light scattering studies show that the flexible globular nanoparticle aggregates undergo a solvent-dependent change in volume (ethanol > dichloromethane > toluene) similar in behavior to hydrogel nanocomposites

  12. Water-soluble PEGylated silicon nanoparticles and their assembly into swellable nanoparticle aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zejing; Li, Yejia; Zhang, Boyu; Purkait, Tapas [Tulane University, Department of Chemistry (United States); Alb, Alina [Tulane University, Department of Physics and Engineering Physics (United States); Mitchell, Brian S. [Tulane University, Department of Chemical and Biomolecular Engineering (United States); Grayson, Scott M.; Fink, Mark J., E-mail: fink@tulane.edu [Tulane University, Department of Chemistry (United States)

    2015-01-15

    Water-soluble silicon nanoparticles were synthesized by grafting PEG polymers onto functionalized silicon nanoparticles with distal alkyne or azide moieties. The surface-functionalized silicon nanoparticles were produced in one step from the reactive high-energy ball milling (RHEBM) of silicon wafers with a mixture of either 5-chloro-1-pentyne in 1-pentyne or 1,7 octadiyne in 1-hexyne to afford air and water-stable chloroalkyl or alkynyl-terminated nanoparticles, respectively. Nanoparticles with the ω-chloroalkyl substituents were easily converted to ω-azidoalkyl groups through the reaction of the Si nanoparticles with sodium azide in DMF. The azido-terminated nanoparticles were then grafted with mono-alkynyl-PEG polymers using a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction to afford core–shell silicon nanoparticles with a covalently attached PEG shell. Covalently linked Si nanoparticle clusters were synthesized via the CuAAC “click” reaction of functional Si NPs with α,ω-functional PEG polymers of various lengths. Dynamic light scattering studies show that the flexible globular nanoparticle aggregates undergo a solvent-dependent change in volume (ethanol > dichloromethane > toluene) similar in behavior to hydrogel nanocomposites.

  13. The niobium oxoazides [NbO(N3)3], [NbO(N3)3·2CH3CN], [(bipy)NbO(N3)3], Cs2[NbO(N3)5] and [PPh4]2[NbO(N3)5].

    Science.gov (United States)

    Haiges, Ralf; Vasiliu, Monica; Dixon, David A; Christe, Karl O

    2016-06-28

    Niobium oxotriazide, [NbO(N3)3], was prepared in a fluoride-azide exchange reaction between [NbOF3] and an excess of Me3SiN3 in SO2 solution. In acetonitrile solution, the fluoride-azide exchange resulted in the isolation of the adduct [NbO(N3)3·2CH3CN]. The subsequent reaction of [NbO(N3)3] with 2,2'-bipyridine (bipy) resulted in the isolation of the bipyridine adduct [(bipy)NbO(N3)3]. The pentaazido anion [NbO(N3)5](2-) was obtained by the reaction of [NbO(N3)3] with two equivalents of ionic azide. The novel niobium oxoazides were fully characterized by their vibrational spectra, impact, friction and thermal sensitivity data and, in the case of [(bipy)NbO(N3)3], Cs2[NbO(N3)5], and [PPh4]2[NbO2(N3)5] by their X-ray crystal structures. PMID:27198621

  14. Induced mutations in pigeon pea (Cajanus cajan (L.) millsp.)

    International Nuclear Information System (INIS)

    Seeds of pigeon pea cv.ICPL-87119 were treated separately with gamma rays, ethyl methane sulphonate (EMS) and sodium azide (SA). Physical and chemical mutagens were found effective in affecting the germination and survival of plants in M1, M2 and M3 generations. However, reduction in survival was more pronounced in M1 as compared to M2 and M3 generation and was increased as the dose or concentration increased. The survival of plants was comparatively affected more than germination of seeds due to the fact that the seedlings failed to grow after primary leaf stage due to shoot and root damage. Seedling damage and reduction in pollen fertility revealed linear trend with increase in dosage of three mutagens. As regards the pollen diameter of both fertile and sterile pollen reduction was more pronounced in EMS and sodium azide as compared to gamma rays. Among the mutagens, sodium azide was the most effective and EMS the least in causing irregularities. The meiotic cell division in the PMC's of morphological variant viz., simple leaf mutant, robust leaf mutant, dwarf and bushy mutant, xantha, branchless, uniculm and bunchy flowered mutant etc. isolated in M2 generation. (author)

  15. Spectral dependence of the initiation threshold of explosive decomposition in AgN3

    International Nuclear Information System (INIS)

    Explosion initiation energy threshold of silver azide was studied for different laser radiation wavelengths. Samples were prepared in the form of pellets (pressed powders), thread-like monocrystals and thin plate polycrystals. A special laser complex was used to perform the experiments. It provided multiparameter measuring of different processes in explosive decomposition of samples. These processes are glowing of decomposing sample, glowing from the irradiated area only, sample acoustic response, shape and energy of a laser pulse. The time resolution for all the experiments made 5 ns and synchronization accuracy made 10 ns. It was found that silver azide demonstrates high sensitivity to laser radiation in its transparent spectral region (1064 nm and 532 nm). The explosion initiation energy threshold made 4–8 mJ/cm2 for both pressed powders with the free surface and for samples with the covered and pressed by a quartz plate surface. Silver azide crystals require approximately 10 times higher energy density to explode. When the samples were acted by UV laser radiation, their sensitivity was from 50 to 500 times lower for the uncovered samples. The covered and pressed samples demonstrated the sensitivity which was close to that for acted by 1064 nm laser radiation. Equal sensitivity of samples to laser radiation with different wavelengths testifies to non-photochemical nature of explosion initiation. The results obtained in the experiments can be consistently explained within the limits of the thermal theory of explosion initiation.

  16. Signaling mechanisms underlying the glioprotective effects of resveratrol against mitochondrial dysfunction.

    Science.gov (United States)

    Bellaver, Bruna; Bobermin, Larissa Daniele; Souza, Débora Guerini; Rodrigues, Marília Danielly Nunes; de Assis, Adriano Martimbianco; Wajner, Moacir; Gonçalves, Carlos-Alberto; Souza, Diogo Onofre; Quincozes-Santos, André

    2016-09-01

    Resveratrol, a polyphenol found in grapes and red wine, exhibits antioxidant, anti-inflammatory, anti-aging and, neuroprotective effects. Resveratrol also plays a significant role modulating glial functionality, protecting the health of neuroglial cells against several neuropsychiatric in vivo and in vitro experimental models. Mitochondrial impairment strongly affected astrocyte functions and consequently brain homeostasis. Molecules that promote astrocyte mitochondrial protection are fundamental to maintain brain energy balance and cellular redox state, contributing to brain healthy. Thus, the present study was designed to evaluate some glioprotective mechanisms of resveratrol against mitochondrial damage promoted by azide exposure in hippocampal primary astrocyte cultures. Azide treatment provoked deleterious effects, including the dysfunction of mitochondria, the deterioration of redox homeostasis, the augmentation of pro-inflammatory cytokines and impairment of glutamate uptake activity. However, resveratrol prevented these effects, protecting hippocampal astrocytes against azide-induced cytotoxicity through the heme-oxygenase-1 (HO-1) pathway and inhibiting p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor kappa B (NFκB) activation. Resveratrol also protected astrocytes via phosphatidylinositide 3-kinase (PI3K)/Akt. These results contribute to the comprehension of the mechanisms by which resveratrol mediates hippocampal astrocyte protection against mitochondrial failure and implicate resveratrol as an important glioprotective molecule. PMID:27373419

  17. Synthesis and reactions of triphenylphosphine-O-benzophenonimine and derivatives

    International Nuclear Information System (INIS)

    O-Amino benzophenone and its para and meta isomers were prepared using Friedl-Craft benzoylation. Their azides were also prepared via their diazonium salts. The azide of o-amino benzophenone in its reduced form (o-benzylaniline) and its cyclic ketal were synthesised. All azides thus formed were reacted separately with triphenylphosphine to give the corresponding phosphinimines, the Wittig reagents nitrogen analog. The reactivity of the phosphorous bond. (P=N) in the different phosphoranes were studied by two types of reactions: (1) the Wittig type of reaction using benzaldehyde and its into derivatives with each of the above prepared phosphinimines. While triphenylphosphine-m-benzophenonimine (ii) and the triphenylphosphine benzophenonimine ethylene acetal (v) and it's reduced form triphenylphosphine-o-benzophenonimine (iv) react giving the corresponding schiffis bases. However, the ortho (i) and the para (iii) isomers failed to react. This lack of reactivity is presumably due to their great stability which came about through the extensive resonance that reduced the nucleophilicity of the nitrogen nucleophiles. (2) The phophinimines each was irradiated using Hanovia medium pressure UV lamp. Also the ortho and para isomers were not affected while others reacted giving the corresponding azo-compound and triphenylphosphine. they were separated and detected by chromatography.(Author)

  18. Biodegradabilite et proprietes energetiques d'elastomeres azotures

    Science.gov (United States)

    Lavoie, Jonathan

    The interest for polymer materials has steadily increased in the last decades and the use of polymer materials has been increasing ever since. These polymers are used in a vast range of applications from civil to military (Colclough et al., 1994; Nair & Laurencin, 2007; Sansone et al., 2012). This demand for polymer materials resulted in the development of various polymers with a wide range of properties depending on the desired application. In the field of propellants, this interest led to the development of glycidyl azide polymer (GAP) and other similar materials. Growing environmental concerns has led to a demand for more environmentally friendly polymers. This demand so far has been increasing and shows no sign of following a different trend for the next years. This demand is in part due to the presence of non-recyclable polymers, for which end of life can be problematic. At the same time, another problematic arose: the soil contamination originating from repeated military training as well as the subsequent contamination of water supplies by rain water seeping into the ground absorbing part of the contaminants (Dontsova, Pennington, Hayes, imunek, & Williford, 2009; M. R. Walsh, Thiboutot, Walsh, & Ampleman, 2012). This phenomenon incurs large decontamination costs and can result in the abandonment of training grounds due to contamination (Michael R. Walsh, Walsh, & Hewitt, 2010). The compounds responsible for the contamination of military training grounds are in part present in elastomers used as binders for propellants. The binders are non-biodegradable as well. In order to make greener propellants, it is not only necessary to replace the contaminants by non-contaminant materials, but also necessary to replace the binder by using new biodegradable materials. Glycidyl azide polymer, a commonly used energetic polymer in binders is non-biodebradable and as such unburned residue will accumulate in the environment. The main objective of this work is to develop new

  19. ANIONIC SYNTHESIS OF A "CLICKABLE" MIDDLE-CHAIN AZIDEFUNCTIONALIZED POLYSTYRENE AND ITS APPLICATION IN SHAPE AMPHIPHILES

    Institute of Scientific and Technical Information of China (English)

    Kan Yue; Jinlin He; Chang Liu; Mingjun Huang; Xue-Hui Dong; Kai Guo; Peihong Ni

    2013-01-01

    "Click chemistry" is,by definition,a general functionalization methodology (GFM) and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis.This paper reports the synthesis of a "clickable" middle-chain azide-functionalized polystyrene (mPS-N3) by anionic polymerization and its application in the preparation of novel shape amphiphiles based on polyhedral oligomeric silsesquioxane (POSS).The mPS-N3 was synthesized by coupling living poly(styryl)lithium chains (PSLi) with 3-chloropropylmethyldichlorosilane and subsequent nucleophilic substitution of the chloro group in the presence of sodium azide.Excess PSLi was end-capped with ethylene oxide to facilitate its removal by flash chromatography.The mPS-N3 was then derived into a giant lipid-like shape amphiphile in two steps following a sequential "click" strategy.The copper(I)-catalyzed azide-alkyne cycloaddition between mPS-N3 and alkyne-functionalized vinyl-substituted POSS derivative (VPOSS-alkyne) ensured quantitative ligation to give polystyrene with VPOSS tethered at the middle of the chain (mPS-VPOSS).The thiol-ene reaction with 1-thioglycerol transforms the vinyl groups on the POSS periphery to hydroxyls,resulting in an amphiphilic shape amphiphile,mPS-DPOSS.This synthetic approach is highly efficient and modular.It demonstrates the "click" philosophy of facile complex molecule construction from a library of simple building blocks and also suggests that mPS-N3 can be used as a versatile "clickable" motif in polymer science for the precise synthesis of complex macromolecules.

  20. The effect of fluorination of zinc oxide nanoparticles on evaluation of their biodistribution after oral administration

    International Nuclear Information System (INIS)

    Monitoring of the behavior of metal nanoparticles in the body following exposure is very important for investigation of the physiological fates and safety of these nanoparticles. In this study, we investigated the behavior and accumulation of nano-scaled ZnO (20 nm) and submicro-scaled ZnO (100 nm) particles in organic tissues after oral administration using PET imaging. Both types of ZnO nanoparticle (20 or 100 nm) were labeled with the radionuclide 18F in high yield via ‘click reaction’. 18F labeling on the ZnO nanoparticles was maintained stably in simulated gastric fluid (pH 1.2) for 7 h. PET images indicated that 18F and 18F-ethoxy azide showed radioactivity in the bone and bladder 3 h after oral administration, whereas radioactivity for 18F-labeled ZnO nanoparticles was seen only in the gastrointestinal (GI) tract. At 5 h post-administration, biodistribution studies demonstrate that 18F accumulated in the bone (10.19 ± 1.1%ID g−1) and 18F-ethoxy azide showed radioactivity in the bone (7.55 ± 0.6%ID g−1), liver, and brain (0.94 ± 0.3%ID g−1). Unlike 18F and 18F-ethoxy azide, 18F-labeled ZnO nanoparticles showed radioactivity in the lung, liver and kidney including the GI tract. Submicro-scaled 18F-labeled ZnO nanoparticles (100 nm) showed stronger radioactivity in the liver and kidney compared to nano-scaled 18F-labeled ZnO nanoparticles (20 nm). In conclusion, PET imaging has the potential to monitor and evaluate the behavior of ZnO nanoparticles absorbed in organic tissues following oral exposures. (paper)

  1. Proton conducting sulphonated fluorinated poly(styrene) crosslinked electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Soules, A.; Ameduri, B.; Boutevin, B.; David, G. [Institut Charles Gerhardt UMR CNRS 5253 Equipe, Ingenierie et Architectures Macromoleculaires,' ' Ecole Nationale Superieure de Chimie de Montpellier, 8 rue de l' Ecole Normale, 34296 Montpellier, Cedex 05 (France); Perrin, R. [CEA Le Ripault Departement des Materiaux, DMAT/SCMF/LSTP, BP16 - 37260 Monts (France); Gebel, G. [Structure et Proprietes des Architectures Moleculaires UMR 5819 (CEA-CNRS-UJF), INAC, SPrAM, CEA Grenoble, 17 Rue des Martyrs, 38054 Grenoble, Cedex 9 (France)

    2011-10-15

    Potential membranes for polymer electrolyte membrane fuel cell based on crosslinked sulphonated fluorinated polystyrenes (PS) were synthesised in two steps. First, azide-telechelic polystyrene was obtained by iodine transfer polymerisation of styrene in the presence of 1,6-diiodoperfluorohexane followed by azido chain-end functionalisation. Then azide-telechelic polystyrene was efficiently crosslinked with 1,10-diazido-1H,1H,2H,2H,9H,9H,10H,10H-perfluorodecane under UV irradiation. After 45 min only, almost completion of azide crosslinking could be achieved, resulting in crosslinked membranes with insoluble fractions higher than 95%. The sulphonation of the crosslinked membranes afforded ionic exchange capacities (IECs) ranging from 2.2 to 3.2 meq g{sup -1}. The hydration number was shown to be very high (from 30 to 75), depending on both the content of perfluorodecane and of sulphonic acid groups. The morphology of the membranes, assessed by small-angle X-ray scattering, was found to be a lamellar-type structure with two types of ionic domains. For the membrane that exhibited an IEC value of 2.2 meq.g{sup -1}, proton conductivity was in the same range as that of Nafion {sup registered} (120-135 mS.cm{sup -1}), whereas the membrane IEC value of 3.2 meq.g{sup -1} showed a proton conductivity higher than that of Nafion {sup registered} in liquid water from 25 to 80 C, though a high water uptake. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhen-Bei, E-mail: 1021453457@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Wu, Jing-Jing, E-mail: 957522275@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Su, Yu, E-mail: 819388710@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Zhou, Jin, E-mail: zhoujin_ah@163.com [Department of Materials and Chemical Engineering, Chizhou University, Muzhi Rd. 199, Chizhou, Anhui 247000 (China); Gao, Yong, E-mail: 154682180@qq.com [School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Yu, Hai-Yin, E-mail: yhy456@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Gu, Jia-Shan, E-mail: jiashanG@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S{sub N}2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface.

  3. In-frame amber stop codon replacement mutagenesis for the directed evolution of proteins containing non-canonical amino acids: identification of residues open to bio-orthogonal modification.

    Directory of Open Access Journals (Sweden)

    James A J Arpino

    Full Text Available Expanded genetic code approaches are a powerful means to add new and useful chemistry to proteins at defined residues positions. One such use is the introduction of non-biological reactive chemical handles for site-specific biocompatible orthogonal conjugation of proteins. Due to our currently limited information on the impact of non-canonical amino acids (nAAs on the protein structure-function relationship, rational protein engineering is a "hit and miss" approach to selecting suitable sites. Furthermore, dogma suggests surface exposed native residues should be the primary focus for introducing new conjugation chemistry. Here we describe a directed evolution approach to introduce and select for in-frame codon replacement to facilitate engineering proteins with nAAs. To demonstrate the approach, the commonly reprogrammed amber stop codon (TAG was randomly introduced in-frame in two different proteins: the bionanotechnologically important cyt b(562 and therapeutic protein KGF. The target protein is linked at the gene level to sfGFP via a TEV protease site. In absence of a nAA, an in-frame TAG will terminate translation resulting in a non-fluorescent cell phenotype. In the presence of a nAA, TAG will encode for nAA incorporation so instilling a green fluorescence phenotype on E. coli. The presence of endogenously expressed TEV proteases separates in vivo target protein from its fusion to sfGFP if expressed as a soluble fusion product. Using this approach, we incorporated an azide reactive handle and identified residue positions amenable to conjugation with a fluorescence dye via strain-promoted azide-alkyne cycloaddition (SPAAC. Interestingly, best positions for efficient conjugation via SPAAC were residues whose native side chain were buried through analysis of their determined 3D structures and thus may not have been chosen through rational protein engineering. Molecular modeling suggests these buried native residues could become partially

  4. A Nanoparticle Platform To Evaluate Bioconjugation and Receptor-Mediated Cell Uptake Using Cross-Linked Polyion Complex Micelles Bearing Antibody Fragments.

    Science.gov (United States)

    Florinas, Stelios; Liu, Marc; Fleming, Ryan; Van Vlerken-Ysla, Lilian; Ayriss, Joanne; Gilbreth, Ryan; Dimasi, Nazzareno; Gao, Changshou; Wu, Herren; Xu, Ze-Qi; Chen, Shaoyi; Dirisala, Anjaneyulu; Kataoka, Kazunori; Cabral, Horacio; Christie, R James

    2016-05-01

    Targeted nanomedicines are a promising technology for treatment of disease; however, preparation and characterization of well-defined protein-nanoparticle systems remain challenging. Here, we describe a platform technology to prepare antibody binding fragment (Fab)-bearing nanoparticles and an accompanying real-time cell-based assay to determine their cellular uptake compared to monoclonal antibodies (mAbs) and Fabs. The nanoparticle platform was composed of core-cross-linked polyion complex (PIC) micelles prepared from azide-functionalized PEG-b-poly(amino acids), that is, azido-PEG-b-poly(l-lysine) [N3-PEG-b-PLL] and azido-PEG-b-poly(aspartic acid) [N3-PEG-b-PAsp]. These PIC micelles were 30 nm in size and contained approximately 10 polymers per construct. Fabs were derived from an antibody binding the EphA2 receptor expressed on cancer cells and further engineered to contain a reactive cysteine for site-specific attachment and a cleavable His tag for purification from cell culture expression systems. Azide-functionalized micelles and thiol-containing Fab were linked using a heterobifunctional cross-linker (FPM-PEG4-DBCO) that contained a fluorophenyl-maleimide for stable conjugation to Fabs thiols and a strained alkyne (DBCO) group for coupling to micelle azide groups. Analysis of Fab-PIC micelle conjugates by fluorescence correlation spectroscopy, size exclusion chromatography, and UV-vis absorbance determined that each nanoparticle contained 2-3 Fabs. Evaluation of cellular uptake in receptor positive cancer cells by real-time fluorescence microscopy revealed that targeted Fab-PIC micelles achieved higher cell uptake than mAbs and Fabs, demonstrating the utility of this approach to identify targeted nanoparticle constructs with unique cellular internalization properties. PMID:27007881

  5. Bio-orthogonal Coupling as a Means of Quantifying the Ligand Density on Hydrophilic Quantum Dots.

    Science.gov (United States)

    Zhan, Naiqian; Palui, Goutam; Merkl, Jan-Philip; Mattoussi, Hedi

    2016-03-01

    We describe the synthesis of two metal-coordinating ligands that present one or two lipoic acid (LA) anchors, a hydrophilic polyethylene glycol (PEG) segment and a terminal reactive group made of an azide or an aldehyde, two functionalities with great utility in bio-orthogonal coupling techniques. These ligands were introduced onto the QD surfaces using a combination of photochemical ligation and mixed cap exchange strategy, where control over the fraction of azide and aldehyde groups per nanocrystal can be easily achieved: LA-PEG-CHO, LA-PEG-N3, and bis(LA)-PEG-CHO. We then demonstrate the application of two novel bio-orthogonal coupling strategies directly on luminescent quantum dot (QD) surfaces that use click chemistry and hydrazone ligation under catalyst-free conditions. We applied the highly efficient hydrazone ligation to couple 2-hydrozinopyridine (2-HP) to aldehyde-functionalized QDs, which produces a stable hydrazone chromophore with a well-defined optical signature. This unique optical feature has enabled us to extract a measure for the ligand density on the QDs for a few distinct sizes and for different ligand architectures, namely mono-LA-PEG and bis(LA)-PEG. We found that the foot-print-area per ligand was unaffected by the nanocrystal size but strongly depended on the ligand coordination number. Additionally, we showed that when the two bio-orthogonal functionalities (aldehyde and azide) are combined on the same QD platform, the nanocrystal can be specifically reacted with two distinct targets and with great specificity. This design yields QD platforms with distinct chemoselectivities that are greatly promising for use as carriers for in vivo imaging and delivery. PMID:26854900

  6. The fermentation of lignocellulose hydrolysates with xylose isomerases and yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Linden, T.

    1992-01-01

    Untreated spent sulphite liquor (SSL) was fermented with Canida tropicalis, Pichia stipitis, Pachysolen tannophilus, Schizosaccharomyces pombe, Saccharomyces cerevisiae and a co-culture of P. Tannophilus and A. cerevisiae, in the presence of xylose isomerases and 4.6 mM azide. The highest yield of ethanol, 0.41 g/g total sugar was obtained with S. cerevisiae, C. tropicalis, and P. tannophilus produced considerble amounts of polyoles, mainly xylitol. With P. stipitis sugar uptake was rapidly inhibited in untreated SSL. The presence of azide contributed to the yield by about 0.04. The fermentation of hydrogen fluoride-pretreated and acid-hydrolysed wheat straw with S. cerevisiae, xylose isomerase, and azide gave a yield of 0.40 g ethanol/g total sugar. In this substrate the xylose utilisation was 84% compared with 51% in SSL. In the concentration range appropriate for enzymatic xylose isomerization, xylulose was measured in a lignocellulose hydrolysate using HPLC with two hydrogen loaded ion exchange columns in series. SSL was used as a model for lignocellulose hydrolysates. The enzymatic isomerization of xylose to xylulose was followed directly in SSL, providing a method for the direct determination of xylose isomerase activity in lignocellulose hydrolysates. Three different xylose isomerase preparations of L. brevis whole cells were compared with a commercial enzyme preparation Maxazyme GI-immob., with respect to activity and stability. From a continuous SSL fermentation plant, two species of yeasts were isolated, S. cerevisiae and Pichia membranaefaciens. One of the isolates of S. cerevisiae, no. 3 was heavily flocculating. Without acetic acid present, both bakers' yeast and isolate no. 3 showed catabolite repression and fermented glucose and galactose sequentially. Galactose fermentation with bakers' yeast was strongly inhibited by acetic acid at pH values below 6. Isolate no. 3 fermented galactose, glucose and mannose, in the presence of acetic acid

  7. A comparison of conventional and click labeling approaches to the synthesis of F-18 labeled glucopyranosyl triazole

    International Nuclear Information System (INIS)

    Radiolabeled glucose analogs are attractive targets for in vivo imaging of glucose metabolism. In the present study, F-18 labeled glucopyranosyl triazole was synthesized using conventional and click labeling approaches, and their results were compared in terms of radiochemical yield, specific activity, and synthesis time. 4-[(2-Fluoroethyl)-1-(-D-glucopyranosyl)]-1H-1, 2, 3-triazole (1) was synthesized by the Cu(I)-catalyzed 1, 3-cycloaddition of tetraacetyl glucopyranosyl azide and 3-butyn-1-ol, hydroxy group fluorination, tetraacetyl group deprotection, and subsequent neutralization. [F-18]1 was synthesized using two conventional radiofluorination of tetraacetyl triazole tosylate precursor, followed by tetraacetyl group deprotection and Cu(I)-catalyzed 1, 3-cycloaddition of F-18 labeled butyne and glucopyranosyl azide. The radiotracer was purified by reverse phase HPLC and co-injected with 1 into a HPLC system to confirm its identity. Non-radiolabeled standard 1 was synthesized in overall 33% yield. In the synthesis of [F-18]1, the click labeling approach was superior to the conventional approach, due to a higher decay-corrected radiochemical yield (30% vs. 21%), higher specific activity (59.9 GBq/mol vs. 23.5 GBq/mol), and shorter synthesis time (75-80 min vs. 95-100 min). In addition, protection of the hydroxy groups of glucopyranosyl azide was not required in the former method. The radiotracer was identified by co-elution with 1 on HPLC. These results demonstrate that click labeling approach is a rapid and efficient method which does not require the protection of functional groups, and that it can readily be applied to the preparation of other radiotracers

  8. Activity-based protein profiling of ammonia monooxygenase in Nitrosomonas europaea.

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Kristen; Sadler, Natalie C.; Wright, Aaron T.; Yeager, Chris; Hyman, Michael R.

    2016-01-29

    Nitrosomonas europaea is an aerobic nitrifying bacterium that oxidizes ammonia (NH3) to nitrite (NO2-) through the sequential activities of ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO). Many alkynes are mechanism-based inactivators of AMO and here we describe an activity-based protein profiling method for this enzyme using 1,7-octadiyne (17OD) as a probe. Inactivation of NH4+-dependent O2 uptake by N. europaea by 17OD was time- and concentration-dependent. The effects of 17OD were specific for ammonia-oxidizing activity and de novo protein synthesis was required to reestablish this activity after cells were exposed to 17OD. Cells were reacted with AlexaFluor 647-azide using a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, solubilized and analyzed by SDS-PAGE and IR scanning. A fluorescent 28 kDa polypeptide was observed for cells previously exposed to 17OD, but not for cells treated with either allylthiourea or acetylene prior to exposure to 17OD, or for cells not previously exposed to 17OD. The 28 kDa polypeptide was membrane-associated and aggregated when heated with β-mercaptoethanol and SDS. The fluorescent 28 kDa polypeptide was also detected in cells pretreated with other diynes, but not in cells pretreated with structural homologs containing a single ethynyl functional group. The membrane fraction from 17OD-treated cells was conjugated with biotin-azide and solubilized in SDS. Streptavidin affinity-purified polypeptides were on-bead trypsin-digested and amino acid sequences of the peptide fragments were determined by LC-MS analysis. Peptide fragments from amoA were the predominant peptides detected in 17OD-treated samples. In gel digestion and MALDI-TOF/TOF analysis also confirmed the fluorescent 28 kDa polypeptide was amoA.

  9. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and SN2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface

  10. Activity-Based Protein Profiling of Ammonia Monooxygenase in Nitrosomonas europaea.

    Science.gov (United States)

    Bennett, Kristen; Sadler, Natalie C; Wright, Aaron T; Yeager, Chris; Hyman, Michael R

    2016-04-01

    Nitrosomonas europaea is an aerobic nitrifying bacterium that oxidizes ammonia (NH3) to nitrite (NO2 (-)) through the sequential activities of ammonia monooxygenase (AMO) and hydroxylamine dehydrogenase (HAO). Many alkynes are mechanism-based inactivators of AMO, and here we describe an activity-based protein profiling method for this enzyme using 1,7-octadiyne (17OD) as a probe. Inactivation of NH4 (+)-dependent O2 uptake by N. europaea by 17OD was time- and concentration-dependent. The effects of 17OD were specific for ammonia-oxidizing activity, andde novoprotein synthesis was required to reestablish this activity after cells were exposed to 17OD. Cells were reacted with Alexa Fluor 647 azide using a copper-catalyzed azide-alkyne cycloaddition (CuAAC) (click) reaction, solubilized, and analyzed by SDS-PAGE and infrared (IR) scanning. A fluorescent 28-kDa polypeptide was observed for cells previously exposed to 17OD but not for cells treated with either allylthiourea or acetylene prior to exposure to 17OD or for cells not previously exposed to 17OD. The fluorescent polypeptide was membrane associated and aggregated when heated with β-mercaptoethanol and SDS. The fluorescent polypeptide was also detected in cells pretreated with other diynes, but not in cells pretreated with structural homologs containing a single ethynyl functional group. The membrane fraction from 17OD-treated cells was conjugated with biotin-azide and solubilized in SDS. Streptavidin affinity-purified polypeptides were on-bead trypsin-digested, and amino acid sequences of the peptide fragments were determined by liquid chromatography-mass spectrometry (LC-MS) analysis. Peptide fragments from AmoA were the predominant peptides detected in 17OD-treated samples. In-gel digestion and matrix-assisted laser desorption ionization-tandem time of flight (MALDI-TOF/TOF) analyses also confirmed that the fluorescent 28-kDa polypeptide was AmoA. PMID:26826234

  11. The structures of the azido-, isocyanato- and isothiocyanato-derivatives of methane and silane and their derivatives. A comparison of ab initio with experimental results

    Science.gov (United States)

    Palmer, Michael H.; Nelson, Alistair D.

    2004-02-01

    The equilibrium structures of various conformers of the azides, isocyanates and isothiocyanates with general type Me 3- nH nW-NXY, together with a small number of their halogenated derivatives, have been determined by Möller-Plessett (MP2) calculations under standard triple zeta valence + polarisation basis set conditions. The structures are compared with each other, with previous and other theoretical studies including CCSD(T) results, and with experimental spectral and diffraction results. The MP2 and CCSD(T) results correlate strongly for a series of these molecules; thus the CCSD(T) bond lengths are larger by about 1.9%. The angles are little different, partly as a result of balancing effects; where some CNN and CNC angles are smaller in CCSD(T) by ˜2-3°, but some CCSD(T) dihedral angles HCNN and HCNC are larger. The MP2 results for the wider group correlate closely with microwave and infrared spectra, and with electron diffraction data. In contrast, the B3LYP method, with the same bases, whilst apparently giving reasonable structures, gives very poor rotation constants, as a result of poor CNC angle determination. The present results suggest that the spectra of ethyl isocyanate, silyl azide, trimethylsilyl azide, and silyl isocyanate require reinvestigation. This is part of a wider study where the central atom W is the series of Group 14 tetrahedral atoms up to Pb; in this study, the central atom W is C and Si, with XY either NN, CO or CS.

  12. Changes in ultraweak luminescence from living fish induced by three chemicals

    International Nuclear Information System (INIS)

    Ultraweak luminescence is a ubiquitous phenomenon in biological systems, which differs from bioluminescence of luciferin-luciferase. This low-intensity emission is inherently associated with the following important process such as oxidative metabolism, cell division, carcinogenesis, photosynthesis, and cell death. In general, ultraweak luminescence may be classified as two kinds, namely spontaneous and induced. Zebra fish is a recommended specimen for toxicity and toxicological test. The purpose of this, the changes before and after the treatment with three chemicals: uranium oxides, sodium azide or cyclophosphamide and their correlations between the dose and effect

  13. Copper (I) iodide nanoparticles on polyaniline as a green, recoverable and reusable catalyst for multicomponent click synthesis of 1,4-disubstituted-1H-1,2,3-triazoles

    OpenAIRE

    Shervin Saadat; Simin Nazari; Mozhgan Afshari; Maryam Shahabi; Mosadegh Keshavarz

    2015-01-01

    A one-pot procedure for the synthesis of 1,4-disubstituted-1H-1,2,3-triazole derivatives via the three component coupling reaction between terminal alkynes, benzyl halides/α-halo ketones and sodium azide in the presences of CuI nanoparticles supported onto polyaniline (Nano CuI/PANI) catalyst in water has been developed. This heterogeneous catalyst showed high catalytic activity and 1,4-regioselectivity for click cyclization in water as a “green” solvent and good to excellent yields were ob...

  14. Breeding of Hordeum Vulgare L. via chemical and physical Mutagenesis

    International Nuclear Information System (INIS)

    A field experiment was conducted under field conditions to compare for yield, yield components and some agronomic traits, of four selective mutants that have been obtained by using chemical mutagen (Sodium Azide) and physical mutagen ( Gamma ray, 20 KG) and their parent Arivate and Numar. The results show that the selective mutants have a high degree of genetic stability and exceeded their parents in some agronomic parameters. There fore, the two best selective mutants were accepted for registration and release under the name of Barrak and Amel as a new varieties by Nacional Committee for Registration and Release of Agricultural varieties

  15. The Non-Isotypical Nitride Selenides Dy3NSe3 and Ho3NSe3: Chains and Dimers

    OpenAIRE

    Lissner, Falk; Schleid, Thomas

    2009-01-01

    Abstract The non-isotypical lanthanoid(III) nitride selenides M3NSe3 of dysprosium (Dy3NSe3) and holmium (Ho3NSe3) are formed by the reaction of the respective rare-earth metal (M = Dy and Ho) with sodium azide (NaN3), selenium and an excess of iodine at 900 ?C from torch-sealed evacuated silica ampoules within seven days. Dy3NSe3 crystallizes orthorhombically (a = 1245.38(9), b = 393.69(3), c = 1303.74(9) pm) in space group Pnma with Z = 4, whereas monoclinic Ho3NSe3 (a = 1152.93(...

  16. Visible Light Driven Photocascade Catalysis: Ru(bpy)3(PF6)2/TBHP-Mediated Synthesis of Fused β-Carbolines in Batch and Flow Microreactors.

    Science.gov (United States)

    Chandrasekhar, D; Borra, Satheesh; Nanubolu, Jagadeesh Babu; Maurya, Ram Awatar

    2016-06-17

    1,2,3,4-Tetrahydro-β-carbolines were coupled with α-keto vinyl azides through an unprecedented visible light-Ru(bpy)3(PF6)2/TBHP mediated photocascade strategy that involves photosensitization, photoredox catalysis and [3 + 2] cycloaddition reaction. The scope and scale-up feasibility of the photocascade strategy was demonstrated by synthesizing 18 different fused β-carbolines in moderate to good yields using batch and continuous flow microreactor. This operationally simple synthetic protocol allows the formation of one C-C and two C-N new bonds in the overall transformation. PMID:27226119

  17. Searching for Electrochemical Reduction Mechanism of Azidophenyl DNA Labels

    Czech Academy of Sciences Publication Activity Database

    Daňhel, Aleš; Trošanová, Zuzana; Balintová, Jana; Hocek, Michal; Fojta, Miroslav

    Ústí nad Labem: Best Servis, 2014 - (Navrátil, T.; Fojta, M.; Pecková, K.), s. 31-35 ISBN 978-80-905221-2-1. [Moderní Elektrochemické Metody /34./. Jetřichovice (CZ), 19.05.2014-23.05.2014] R&D Projects: GA ČR GBP206/12/G151; GA MŠk EE2.3.30.0019 Institutional support: RVO:68081707 ; RVO:61388963 Keywords : aromatic azides * DNA labels * mercury electrode * reduction mechanism * voltammetry Subject RIV: CG - Electrochemistry

  18. Preparation of significant complexes of selected transition elements with appropriate ligands

    International Nuclear Information System (INIS)

    New complexes of copper (II), nickel (II) and cobalt (II) have been prepared using triphenylphosphine and benzofurazan-1-oxide as ligands. Benzofurazan-1-oxide was prepared from the reaction between o-nitrophenyl azide and toluene as a catalyst. These complexes have been identified by means of infra-red spectra and also melting points determination. The coordination bonding was found to be through phosphorus-metal and nitrogen-metal. The melting points and colour confirmed are used as initial confirmation or identification procedure. Stability constants were studied to the new complexes prepared which is in good agreement with reported value for similar complexes. (Author)

  19. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.; Larsen, Niels Bent;

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface. B...... method has been applied for anchoring of the chelating agent nitrilotriacetic acid (NTA) on the conductive polymer. The chelating linkage ability of NTA on the surface was investigated through a sandwich ELISA study confirming the selective bonding of a histidine tagged protein....

  20. One-pot synthesis of Au@SiO2 catalysts: A click chemistry approach

    KAUST Repository

    Solovyeva, Vera A.

    2014-10-13

    Using the copper-catalyzed azide-alkyne cycloaddition "click" reaction, a library of triazole amphiphiles with a variety of functional polar "heads" and hydrophobic or superhydrophobic "tails" was synthesized. The amphiphiles were evaluated for their ability to stabilize small Au nanoparticles, and, at the same time, serve as templates for nanocasting porous SiO2. One of the Au@SiO2 materials thus prepared was found to be a highly active catalyst for the Au nanoparticle-catalyzed regioselective hydroamination of alkynes.

  1. Biochemical requirements for singlet oxygen production by purified human myeloperoxidase.

    OpenAIRE

    Kanofsky, J R; Wright, J; Miles-Richardson, G E; Tauber, A I

    1984-01-01

    The myeloperoxidase (MPO)-hydrogen peroxide (H2O2)-halide systems were found to produce chemiluminescence at 1,268 nm, a characteristic emission band for singlet oxygen (1O2). The emission was enhanced by a factor of 29 +/- 5 in deuterium oxide and was inhibited by the 1O2 quenchers, histidine and azide ion. Inactivation of MPO with heat or with cyanide ion prevented light production. The combined weight of all data strongly supported the production of 1O2 by these enzyme systems. The amount ...

  2. Synthesis of selected 5-thio-substituted tetrazole derivatives and evaluation of their antibacterial and antifungal activities

    OpenAIRE

    NALILU SUCHETHA KUMARI; PALUSA SANATH KUMAR GOUD; RAMASWAMY VENKAT RAGAVAN; KASI REGURAMAN JAI SANKAR; KUBARAN KUMARAN; SUBAN SHAFI SYED; VARADARAJI DHAYANITHI; HARI NARAYAN PATI

    2011-01-01

    Several 5-thio-substituted tetrazole derivatives were efficiently synthesized by a three-step process. The substituted tetrazol-5-thiol, namely, 1-benzyl-1H-tetrazole-5-thiol (2) was prepared by refluxing commercially available benzyl isothiocyanate (1) with sodium azide in water. The second step was the synthesis of 1-benzyl-5-[(3-bromopropyl)thio]-1H-tetrazole (3) by thioalkylation of tetrazole-5-thiol 2 with 1,3-dibromopropane in tetrahydrofuran. Finally, the 5-thio-substituted tetrazole d...

  3. InCl3-Catalyzed [2+3] Cycloaddition Reaction: A Rapid Synthesis of 5-Substituted 1H-tetrazole under Microwave Irradiation

    OpenAIRE

    Patil, Vijay S.; Nandre, Kamlakar P.; Borse, Amulrao U.; Sidhanath V. Bhosale

    2012-01-01

    A series of 5-substituted 1H-tetrazole were efficiently prepared by InCl3 catalyzed (10 mol %) from structurally divert organic nitriles with sodium azide under the influence of microwave irradiation. The present protocol was successfully applied to the aliphatic, aryl, benzylic and heterocyclic nitriles and corresponding 5-substituted 1H-tetrazole were obtained in good to excellent yield (70-96%). This method gives remarkable advantages such as short reaction time, simple work-up procedure a...

  4. Poly[(μ2-azido-κ2N1:N1[μ2-5-(8-quinolyloxymethyltetrazolato-κ4N1,O,N5:N4]zinc(II

    Directory of Open Access Journals (Sweden)

    Hong-ling Cai

    2009-06-01

    Full Text Available In the title compound, [Zn(C11H8N5O(N3]n, the Zn atom is hexacoordinated by five N atoms and one O atom in a distorted octahedral geometry. The chelating 5-(8-quinolyloxymethyltetrazolate ligands are approximately planar, with a dihedral angle of 3.6 (2° between the quinoline and tetrazole planes. Adjacent Zn atoms are linked by two bridging azide ligands across a centre of inversion, and further coordination by one N atom of an adjacent tetrazole unit forms two-dimensional frameworks in (100. C—H...N interactions exist between ligands in neighbouring layers.

  5. A novel approach for the synthesis of 5-substituted-1H-tetrazoles

    Energy Technology Data Exchange (ETDEWEB)

    Akhlaghinia, Batool; Rezazadeh, Soodabeh, E-mail: akhlaghinia@um.ac.ir [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2012-12-15

    A series of 5-substituted-1H-tetrazoles (RCN{sub 4}H) have been synthesized by cycloaddition reaction of different aryl and alkyl nitriles with sodium azide in DMSO using CuSO{sub 4}{center_dot}5H{sub 2}O as catalyst. A wide variety of aryl nitriles underwent [3+2] cycloaddition to afford tetrazoles under mild reaction conditions in good to excellent yields. The catalyst used is readily available and environmentally friendly. Short reaction times, good to excellent yields, safe process and simple workup make this method an attractive and useful contribution to present organic synthesis of 5-substituted-1H-tetrazoles. (author)

  6. Synthesis of heteroglycoclusters by using orthogonal chemoselective ligations

    Directory of Open Access Journals (Sweden)

    Baptiste Thomas

    2012-03-01

    Full Text Available Synthetic heteroglycoclusters are being subjected to increasing interest due to their potential to serve as selective ligands for carbohydrate-binding proteins. In this paper, we describe an expedient strategy to prepare cyclopeptides displaying well-defined distributions and combinations of carbohydrates. By using both oxime ligation and copper(I-catalyzed alkyne–azide cycloaddition, two series of compounds bearing binary combinations of αMan, αFuc or βLac in an overall tetravalent presentation, and either 2:2 or 3:1 relative proportions, have been prepared.

  7. Synthesis and In Vitro Antiproliferative Activity of Novel Androst-5-ene Triazolyl and Tetrazolyl Derivatives

    Directory of Open Access Journals (Sweden)

    János Wölfling

    2011-06-01

    Full Text Available A straightforward and reliable method for the regioselective synthesis of steroidal 1,4-disubstituted triazoles and 1,5-disubstituted tetrazoles via copper(I-catalyzed cycloadditions is reported. Heterocycle moieties were efficiently introduced onto the starting azide compound 3β-acetoxy-16β-azidomethylandrost-5-en-17β-ol through use of the “click” chemistry approach. The antiproliferative activities of the newly-synthesized triazoles were determined in vitro on three human gynecological cell lines (HeLa, MCF7 and A2780 using the microculture tetrazolium assay.

  8. Water soluble (Eta sup (6) - arene) ruthenium (II) complexes incorporating marine derived bioligand: Synthesis, spectral and structural studies

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; PrabhaDevi; Mozharivskyj, Y.

    compounds. During the course of our study on bioactive compounds from marine organisms we isolated kojic acid from a marine fungus Aspergillus species. Kojic acid is one of the metabolite produced by various fungal or bacteria strains... the reaction of [(η 6 - arene)Ru(HMP)Cl] with sodium azide to yield azido dimeric complexes [{(η 6 -arene)Ru(μN 3 )N 3 } 2 ] and [{(η 6 -arene)Ru(μN 3 )Cl} 2 ]. The complexes are fully characterized on the basis of FTIR and NMR spectroscopic data...

  9. Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    PENG Xian-fu; LI Hong-qi

    2009-01-01

    Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

  10. Microbial transglutaminase displays broad acyl-acceptor substrate specificity

    DEFF Research Database (Denmark)

    T. Gundersen, Maria; Keillor, Jeffrey W.; Pelletier, Joelle N.

    2013-01-01

    The great importance of amide bonds in industrial synthesis has encouraged the search for efficient catalysts of amide bond formation. Microbial transglutaminase (MTG) is heavily utilized in crosslinking proteins in the food and textile industries, where the side chain of a glutamine reacts with....... Importantly, very small amines carrying either the electron-rich azide or the alkyne groups required for click chemistry were highly reactive as acyl-acceptor substrates, providing a robust route to minimally modified, “clickable” peptides. These results demonstrate that MTG is tolerant to a variety of...

  11. Synthesis of an antimetastatic tetrasaccharide β-D-Gal-(1 → 4)-β-D-GlcpNAc-(1 → 6)-α-D-Manp-(1 → 6)-β-D-Manp-Ome

    Institute of Scientific and Technical Information of China (English)

    Kai Jun Liao; Xiao Feng Jin; Xiang Bao Meng; Chen Li; Zhong Jun Li

    2012-01-01

    An antimetastatic tetrasaccharide T1,β-D-Gal-(1 → 4)-β-D-GlcpNAc-(1 → 6)-α-D-Manp-(1 → 6)-β-D-Manp-OMe,was synthesized with two approaches.The first approach was a conventional method employing thioglycoside and Koenigs-Knorr glycosylation reaction in 24% overall yield.The second one was a novel route through the azidoiodo-glycosylation strategy by using 2-iodo-2-deoxylactosyl azide as the donor in 36% overall yield.

  12. Critical phenomena and new effects in the physical acoustics of solids

    International Nuclear Information System (INIS)

    Experimental results on the variations of the acoustical parameters of crystal in the vicinity of their critical states are given; these variations represent new effects in the physical acoustics of solid, called acoustic splitting and internal friction oscillations. The new effects are illustrated in potassium nitrite and potassium nitrate, thallium nitrate, ammonium Perchlorate, silver azide, and in high-temperature superconductors made from yttrium - barium cuprate. Three types of acoustic splitting are discussed, depending on the nature of the phase transition and other factors. An approach is proposed as a possible means of explaining the observed effects on the basis of the notion of anomalous heterophase fluctuations

  13. Dimethyl Sulfide Production from Dimethylsulfoniopropionate in Coastal Seawater Samples and Bacterial Cultures †

    OpenAIRE

    Kiene, Ronald P.

    1990-01-01

    Dimethyl sulfide (DMS) was produced immediately after the addition of 0.1 to 2 μM β-dimethylsulfonio-propionate (DMSP) to coastal seawater samples. Azide had little effect on the initial rate of DMS production from 0.5 μM added DMSP, but decreased the rate of production after 6 h. Filtration of water samples through membrane filters (pore size, 0.2 μm) greatly reduced DMS production for approximately 10 h, after which time DMS production resumed at a high rate. Autoclaving completely eliminat...

  14. Seed protein improvement in wheat and pulses through induced mutation

    International Nuclear Information System (INIS)

    Gamma rays and chemical mutagens (sodium azide and ethyl methane sulphonate) were used separately to induce mutations in wheat, triticale and mungbean. An increased variation in yield and protein content, determined by dye-binding capacity and the micro-Kjeldahl method, was observed in the M3 and M4 generations as compared with controls. In fertilizer trials an increase in grain yield and protein percentage was found invariably in all the treatments given at different stages in split applications. The genetic diversity was observed in the collections from northern areas of Pakistan regarding the protein content and morphological and physiological characters. (author)

  15. A method for measuring fatty acid oxidation in C. elegans

    DEFF Research Database (Denmark)

    Elle, Ida Coordt; Rødkær, Steven Vestergaard; Fredens, Julius; Færgeman, Nils J.

    2012-01-01

    recent studies have recognized the central role of fatty acid degradation in cellular lipid homeostasis. In the present study, we show how complete oxidation of fatty acids can be determined in live C. elegans by examining oxidation of tritium-labeled fatty acids to tritiated H2O that can be measured by...... scintillation counting. Treating animals with sodium azide, an inhibitor of the electron transport chain, reduced (3)H2O production to approximately 15%, while boiling of animals prior to assay completely blocked the production of labeled water. We demonstrate that worms fed different bacterial strains exhibit...

  16. DNA Three Way Junction Core Decorated with Amino Acids-Like Residues-Synthesis and Characterization †

    Directory of Open Access Journals (Sweden)

    Claudia Addamiano

    2016-08-01

    Full Text Available Construction and physico-chemical behavior of DNA three way junction (3WJ functionalized by protein-like residues (imidazole, alcohol and carboxylic acid at unpaired positions at the core is described. One 5′-C(S-propargyl-thymidine nucleotide was specifically incorporated on each strand to react through a post synthetic CuACC reaction with either protected imidazolyl-, hydroxyl- or carboxyl-azide. Structural impacts of 5′-C(S-functionalization were investigated to evaluate how 3WJ flexibility/stability is affected.

  17. DNA Three Way Junction Core Decorated with Amino Acids-Like Residues-Synthesis and Characterization.

    Science.gov (United States)

    Addamiano, Claudia; Gerland, Béatrice; Payrastre, Corinne; Escudier, Jean-Marc

    2016-01-01

    Construction and physico-chemical behavior of DNA three way junction (3WJ) functionalized by protein-like residues (imidazole, alcohol and carboxylic acid) at unpaired positions at the core is described. One 5'-C(S)-propargyl-thymidine nucleotide was specifically incorporated on each strand to react through a post synthetic CuACC reaction with either protected imidazolyl-, hydroxyl- or carboxyl-azide. Structural impacts of 5'-C(S)-functionalization were investigated to evaluate how 3WJ flexibility/stability is affected. PMID:27563857

  18. Diazidobis[4,4,5,5-tetramethyl-2-(1,3-thiazol-2-yl-2-imidazoline-1-oxyl-3-oxide-κ2O,N]manganese(II

    Directory of Open Access Journals (Sweden)

    Kai Jiang

    2009-02-01

    Full Text Available In the crystal structure of the title compound, [Mn(N32(C10H14N3O2S2], the Mn(II atom exhibits a roughly octahedral coordination geometry. The Mn(II atom lies on an inversion centre, thus the asymmetric unit comprises one half-molecule. The metal center is six-coordinated by two azide anions and by two chelating 4,4,5,5-tetramethyl-2-(1,3-thiazol-2-yl-2-imidazoline-1-oxyl-3-oxide nitronyl nitroxide radical ligands, leading to two six-membered chelate rings.

  19. Multichromophoric sugar for fluorescence photoswitching

    Directory of Open Access Journals (Sweden)

    Stéphane Maisonneuve

    2014-06-01

    Full Text Available A multichromophoric glucopyranoside 2 bearing three dicyanomethylenepyran (DCM fluorophores and one diarylethene (DAE photochrome has been prepared by Cu(I-catalyzed alkyne–azide cycloaddition reaction. The fluorescence of 2 was switched off upon UV irradiation, in proportion with the open to closed form (OF to CF conversion extent of the DAE moiety. A nearly 100% Förster-type resonance energy transfer (FRET from all three DCM moieties to a single DAE (in its CF moiety was achieved. Upon visible irradiation, the initial fluorescence intensity was recovered. The observed photoswiching is reversible, with excellent photo resistance.

  20. Synthèse et étude d'un complexe de cuivre(II) tensioactif, fluorophile et photoréductible : application à la chimie click en millieux biphasiques perfluorocarbure-eau et hydrocarbure-eau

    OpenAIRE

    Jochyms, Quentin

    2015-01-01

    The aim of this thesis was to develop a new metallosurfactant for the catalysis between an alkyne and an azide. The goal of such a system was to keep separated the reactants and the catalyst in two different phases to facilitate the purification of the reaction mixture. The first step was to synthetized the complex [Cu(TF6)(3-benzoylbenzoate)2]. Then it was shown that this complex, insoluble in water and DIPE-water. This complex is also photoreductible to form a copper(I) complex. Finally, it...

  1. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.

    2012-05-09

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

    OpenAIRE

    Zhan-Jiang Zheng; Ding Wang; Zheng Xu; Li-Wen Xu

    2015-01-01

    The Cu(I)-catalyzed azide-alkyne cycloaddition reaction, also known as click chemistry, has become a useful tool for the facile formation of 1,2,3-triazoles. Specifically, the utility of this reaction has been demonstrated by the synthesis of structurally diverse bi- and bis-1,2,3-triazoles. The present review focuses on the synthesis of such bi- and bistriazoles and the importance of using copper-promoted click chemistry (CuAAC) for such transformations. In addition, the application of bitri...

  3. Synthesis of Glycosyl Amides Using Selenocarboxylates as Traceless Reagents for Amide Bond Formation.

    Science.gov (United States)

    Silva, Luana; Affeldt, Ricardo F; Lüdtke, Diogo S

    2016-07-01

    Carbohydrate-derived amides were successfully prepared in good yields from a broad range of substrates, including furanosyl and pyranosyl derivatives. The methodology successfully relied on the in situ generation of lithium selenocarboxylates from Se/LiEt3BH and acyl chlorides or carboxylic acids and their reaction with sugar azides. A key aspect of the present protocol is that we start from elemental selenium; isolation and handling of all reactive and sensitive selenium-containing intermediates is avoided, therefore providing the selenocarboxylate the status of a traceless reagent. PMID:27275515

  4. 64Cu Core-labeled Nanoparticles with High Specific Activity via Metal-Free Click Chemistry

    OpenAIRE

    Zeng, Dexing; Lee, Nam S.; Liu, Yongjian; Zhou, Dong; Dence, Carmen S.; Wooley, Karen L.; Katzenellenbogen, John A.; Welch, Michael J.

    2012-01-01

    A novel strategy based on metal-free click chemistry was developed for the copper-64 radiolabeling of the core in shell-crosslinked nanoparticles (SCK-NPs). Compared with Cu(I)-catalyzed click chemistry, this metal-free strategy provides the following advantages for Cu-64 labeling of the core of SCK-NPs: (1) elimination of copper exchange between non-radioactive Cu in the catalyst and DOTA-chelated Cu-64; (2) elimination of the internal “click” reactions between the azide and acetylene groups...

  5. Ionization of covalent immobilized poly(4-vinylphenol) monolayers measured by ellipsometry, QCM and SPR

    Energy Technology Data Exchange (ETDEWEB)

    Uppalapati, Suji [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); Kong, Na; Norberg, Oscar [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Ramström, Olof, E-mail: ramstrom@kth.se [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Yan, Mingdi, E-mail: Mingdi_Yan@uml.edu [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden)

    2015-07-15

    Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surfaces followed by UV irradiation. The pH-responsive behavior of these PVP ultrathin films was evaluated by ellipsometry, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). By monitoring the responses of these films to pH in situ, the ionization constant of the monolayer thin films was obtained. The apparent pK{sub a} value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution.

  6. Triazole-containing N-acyl homoserine lactones targeting the quorum sensing system in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert; Jakobsen, Tim H.; Bang, Claus Gunnar;

    2015-01-01

    pathogenesis and antibiotic tolerance of a bacterial biofilm. To identify the structural elements important for antagonistic or agonistic activity against the Pseudomonas aeruginosa LasR protein, we report the synthesis and screening of new triazole-containing mimics of natural N-acyl homoserine lactones. A...... series of azide- and alkyne-containing homoserine lactone building blocks was used to prepare an expanded set of 123 homoserine lactone analogues through a combination of solution- and solid-phase synthesis methods. The resulting compounds were subjected to cell-based quorum sensing screening assays...

  7. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells

    KAUST Repository

    Rumer, Joseph W.

    2015-02-01

    A bis-azide-based small molecule crosslinker is synthesized and evaluated as both a stabilizing and efficiency-boosting additive in bulk heterojunction organic photovoltaic cells. Activated by a noninvasive and scalable solution processing technique, polymer:fullerene blends exhibit improved thermal stability with suppressed polymer skin formation at the cathode and frustrated fullerene aggregation on ageing, with initial efficiency increased from 6% to 7%. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis and study of a fluorous and photoreductible copper(II) complex with surfactant properties : application to click chemistry in biphasic perfluorocarbon-water and hydrocarbon-water systems

    OpenAIRE

    Jochyms, Quentin

    2015-01-01

    The aim of this thesis was to develop a new metallosurfactant for the catalysis between an alkyne and an azide. The goal of such a system was to keep separated the reactants and the catalyst in two different phases to facilitate the purification of the reaction mixture. The first step was to synthetized the complex [Cu(TF6)(3-benzoylbenzoate)2]. Then it was shown that this complex, insoluble in water and DIPE-water. This complex is also photoreductible to form a copper(I) complex. Finally, it...

  9. Synthesis of Conformationally Locked Versions of Puromycin Analogues

    Science.gov (United States)

    Saneyoshi, Hisao; Michel, Benoît Y.; Choi, Yongseok; Strazewski, Peter; Marquez, Victor E.

    2009-01-01

    Conformationally locked North and South versions of puromycin analogues built on a bicyclo[3.1.0]hexane pseudosugar template were synthesized. The final assembly of the products was accomplished by the Staudinger-Vilarrasa coupling of the corresponding North (2 and 3) and South (6 and 7) 3′-azidopurine carbanucleosides with the Fmoc-protected 1-hydroxybenzotriazole ester of 4-methoxy-L-tyrosine. North azides 2 and 3 were reported earlier. The 3′-azido intermediates 6 and 7 that are necessary for the synthesis of the South puromycin analogues are described herein for the first time. PMID:18991379

  10. Polysaccharides: The “Click” Chemistry Impact

    Directory of Open Access Journals (Sweden)

    Romain Lucas

    2011-09-01

    Full Text Available Polysaccharides are complex but essential compounds utilized in many areas such as biomaterials, drug delivery, cosmetics, food chemistry or renewable energy. Modifications and functionalizations of such polymers are often necessary to achieve molecular structures of interest. In this area, the emergence of the “click” chemistry concept, and particularly the copper-catalyzed version of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides, had an impact on the polysaccharides chemistry. The present review summarizes the contribution of “click” chemistry in the world of polysaccharides.

  11. INDUCED GENETIC VARIABILITY FOR SEED GERMINATION AND OTHER YIELD PARAMETERS IN KIDNEY BEAN (PHASEOLUS VULGARIS L.).

    OpenAIRE

    Asad Ali; Bhanita Talukdar; Bhojaraja Naik

    2014-01-01

    Kidney bean (Phaseolus vulgaris L.) is the most ancient cultivated crops among the legumes. It is commonly used for human nutrition, animal feed and soil fertility. Seeds of two local dwarf varieties of kidney bean, B1-Local and B2-Local were subjected to different concentrations (0.1%, 0.3 %, 0.5%, 1.0% and 1.5%) of sodium azide (SA). Effects of chemical mutagen were evaluated for seed germination, plant survival, plant height, number of branch per plant; number of leaves...

  12. UV-B-induced anthocyanin synthesis in maize regulated by FMN and inhibitors of FMN photoreactions

    International Nuclear Information System (INIS)

    Anthocyanin synthesis in maize (Zea mays L., cv. ganga safed) under white and UV-B light has been investigated after pretreatment of seedlings with flavin mononucleotide (FMN) and inhibitors of flavin photoreactions. UV-B enhanced synthesis of anthocyanin compared to white light, and this enhancement was further promoted by flavin mononucleotide (FMN). Salicyl hydroxamic acid, sodium azide and potassium iodide, which interfere with the photoreactions of flavin, inhibit UV-B-induced and FMN-promoted anthocyanin synthesis. A flavin may be involved as a photoreceptor of UV-B radiation for anthocyanin synthesis in maize

  13. Synthesis, structure and in vitro cytostatic activity of ferrocene-Cinchona hybrids.

    Science.gov (United States)

    Kocsis, László; Szabó, Ildikó; Bősze, Szilvia; Jernei, Tamás; Hudecz, Ferenc; Csámpai, Antal

    2016-02-01

    Exploring copper(I)- and ruthenium(II)-catalyzed azide-alkyne cycloadditions and a Sonogashira protocol, novel cytostatic ferrocene-cinchona hybrids were synthetized displaying significant in vitro activity on HepG-2 and HT-29 cells. Preliminary SAR studies disclosed that compounds incorporating linkers with 1,2,3-triazole and chalchone residues can be considered as promising lead structures. According to the best of our knowledge this is the first letter on the incorporation of ferrocene nucleus in the reputed cinchona family via triazole and chalcone linkers with established pharmaceutical profile. PMID:26739780

  14. A new efficient route for the synthesis of 4,4′,6,6′-tetra(azido) azo- 1,3,5-triazine

    Institute of Scientific and Technical Information of China (English)

    Xiao Tong Li; Sheng Hua Li; Si Ping Pang; Yong Zhong Yu; Yun Jun Luo

    2007-01-01

    A new method for the synthesis of 4,4′,6,6′-tetra(azido)azo- 1,3,5-triazine (TAAT) is described. The key intermediate 4,4′,6,6′-tetra(azido)hydrazo-1,3,5-triazine (THAT) was synthesized by nucleophilic substitution in the case of sodium azide as nucleophile.N-Bromosuccinide (NBS) was used as oxidant to oxidize THAT by a tractable operation under mild reaction condition. The target compound TAAT was obtained with a facile process and high overall yield of 81%. The structures of TAAT and its intermediates were identified by spectroscopic methods.

  15. End group functionalization of poly(ethylene glycol with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

    Directory of Open Access Journals (Sweden)

    Carolin Fleischmann

    2014-09-01

    Full Text Available The synthesis of a new phenolphthalein azide derivative, which can be easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-β-cyclodextrin-dipentaerythritol, the formation of stable inclusion complexes was observed, representing an interesting approach towards the formation of star shaped polymers. The decolorization of a basic polymer solution caused by the complexation was of great advantage since this behavior enabled following the complex formation by UV–vis spectroscopy and even the naked eye.

  16. One-step ligand exchange reaction as an efficient way for functionalization of magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mrowczynski, Radoslaw [Humboldt-University Berlin, Department of Chemistry (Germany); Rednic, Lidia; Turcu, Rodica [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania); Liebscher, Juergen, E-mail: liebscher@chemie.hu-berlin.de [Humboldt-University Berlin, Department of Chemistry (Germany)

    2012-07-15

    Novel magnetic Fe{sub 3}O{sub 4} nanoparticles (NPs) covered by one layer of functionalized fatty acids, bearing entities (Hayashi catalyst, biotin, quinine, proline, and galactose) of high interest for practical application in nanomedicine or organocatalysis, were synthesized. The functionalized fatty acids were obtained by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) of azido fatty acids with alkynes. All the magnetic NPs show superparamagnetic behavior with high values of magnetization and high colloidal stability in DCM solution.

  17. Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

    Science.gov (United States)

    Wang, Ding; Xu, Zheng

    2015-01-01

    Summary The Cu(I)-catalyzed azide-alkyne cycloaddition reaction, also known as click chemistry, has become a useful tool for the facile formation of 1,2,3-triazoles. Specifically, the utility of this reaction has been demonstrated by the synthesis of structurally diverse bi- and bis-1,2,3-triazoles. The present review focuses on the synthesis of such bi- and bistriazoles and the importance of using copper-promoted click chemistry (CuAAC) for such transformations. In addition, the application of bitriazoles and the related CuAAAC reaction in different fields, including medicinal chemistry, coordination chemistry, biochemistry, and supramolecular chemistry, have been highlighted. PMID:26734102

  18. Hypervalent iodine(iii)-promoted N-incorporation into N-aryl vinylogous carbamates to quinoxaline diesters: access to 1,4,5,8-tetraazaphenanthrene.

    Science.gov (United States)

    Sagar, A; Vidaycharan, Shinde; Shinde, Anand H; Sharada, Duddu S

    2016-04-26

    A novel oxidative N-incorporation strategy for synthesis of quinoxaline diesters under metal-free conditions is described for the first time. The mild reaction conditions allow for this transformation via the formation of two C(sp(2))-N bonds utilizing cheaply available NaN3 as the N-atom source. N-Aryl vinylogous carbamates in this study undergo azidation at enamino C(sp(2))-H selectively. The robustness of this strategy is further demonstrated by the synthesis of a valuable 1,4,5,8-tetraazaphenanthrene derivative using a mild and convenient approach. PMID:27050385

  19. 5-Azido-4-dimethylamino-1-methyl-1,2,4-triazolium Hexafluoridophosphate and Derivatives

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2016-02-01

    Full Text Available 5-Azido-4-(dimethylamino-1-methyl-1,2,4-triazolium hexafluoridophosphate was synthesized from the corresponding 5-bromo compound with NaN3. Reaction with bicyclo[2.2.1]hept-2-ene yielded a tricyclic aziridine, addition of an N-heterocyclic carbene resulted in a triazatrimethine cyanine, and reduction with triphenylphosphane gave the 5-amino derivative. The crystal structures of three nitrogen-rich salts were determined. Thermoanalysis of the cationic azide and triazene showed exothermal decomposition. The triazene exhibited negative solvatochromism in polar solvents involving the dipolarity π* and hydrogen-bond donor acidity α of the solvent.

  20. Triazolyl-Based Molecular Gels as Ligands for Autocatalytic 'Click' Reactions.

    Science.gov (United States)

    Araújo, Marco; Díaz-Oltra, Santiago; Escuder, Beatriu

    2016-06-13

    The catalytic performance of triazolyl-based molecular gels was investigated in the Huisgen 1,3-dipolar cycloaddition of alkynes and azides. Low-molecular-weight gelators derived from l-valine were synthesized and functionalized with a triazole fragment. The resultant compounds formed gels either with or without copper, in a variety of solvents of different polarity. The gelators coordinated Cu(I) and exhibited a high catalytic activity in the gel phase for the model reaction between phenylacetylene and benzylazide. Additionally, the gels were able to participate in autocatalytic synthesis and the influence of small structural changes on their performance was observed. PMID:27168408

  1. A New Multicomponent Multicatalyst Reaction (MC)(2)R: Chemoselective Cycloaddition and Latent Catalyst Activation for the Synthesis of Fully Substituted 1,2,3-Triazoles.

    Science.gov (United States)

    Yamamoto, Kosuke; Bruun, Theodora; Kim, Jung Yun; Zhang, Lei; Lautens, Mark

    2016-06-01

    A multicomponent multicatalyst reaction (MC)(2)R for constructing fully substituted 1,2,3-triazoles is reported. An application of chemoselectivity and latent catalysis in a sequence of multicatalytic reactions confers control over a number of undesired processes, where all of the reagents coexist in the same reaction vessel. The sequence of a chemoselective copper-catalyzed azide alkyne cycloaddition followed by a palladium/copper-catalyzed Sonogashira cross-coupling afforded 1,2,3-triazoles regioselectively with good to high yields and a broad scope. PMID:27213631

  2. Postsynthetic modification of metal-organic framework for hydrogen sulfide detection

    Science.gov (United States)

    Zhang, Xin; Zhang, Jianmin; Hu, Quan; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2015-11-01

    Hydrogen sulfide (H2S) has recently been identified as the third biological gaseous messenger (gasotransmitter) that is involved in regulating many important physiological processes. The detection of H2S is thus essential for its roles but remain challenging in living systems. We report herein a novel turn-on fluorescent probe for H2S detection based on azide functionalized metal-organic framework (MOF). The MOF probe displayed high sensitivity (detection limit, 28.3 μM), excellent selectivity, and fast response (MOF probe can be employed as a useful tool to further elucidate the biological roles of H2S.

  3. Degradable polymeric nanoparticles by aggregation of thermoresponsive polymers and ``click'' chemistry

    Science.gov (United States)

    Dworak, Andrzej; Lipowska, Daria; Szweda, Dawid; Suwinski, Jerzy; Trzebicka, Barbara; Szweda, Roza

    2015-10-01

    This study describes a novel approach to the preparation of crosslinked polymeric nanoparticles of controlled sizes that can be degraded under basic conditions. For this purpose thermoresponsive copolymers containing azide and alkyne functions were obtained by ATRP of di(ethylene glycol) monomethyl ether methacrylate (D) and 2-aminoethyl methacrylate (A) followed by post polymerization modification. The amino groups of A were reacted with propargyl chloroformate or 2-azido-1,3-dimethylimidazolinium hexafluorophosphate, which led to two types of copolymers. Increasing the temperature of aqueous solutions of the mixed copolymers caused their aggregation into spherical nanoparticles composed of both types of chains. Their dimensions could be controlled by changing the concentration and heating rate of the solutions. Covalent stabilization of aggregated chains was performed by a ``click'' reaction between the azide and alkyne groups. Due to the presence of a carbamate bond the nanoparticles undergo pH dependent degradation under mild basic conditions. The proposed procedure opens a route to new carriers for the controlled release of active species.This study describes a novel approach to the preparation of crosslinked polymeric nanoparticles of controlled sizes that can be degraded under basic conditions. For this purpose thermoresponsive copolymers containing azide and alkyne functions were obtained by ATRP of di(ethylene glycol) monomethyl ether methacrylate (D) and 2-aminoethyl methacrylate (A) followed by post polymerization modification. The amino groups of A were reacted with propargyl chloroformate or 2-azido-1,3-dimethylimidazolinium hexafluorophosphate, which led to two types of copolymers. Increasing the temperature of aqueous solutions of the mixed copolymers caused their aggregation into spherical nanoparticles composed of both types of chains. Their dimensions could be controlled by changing the concentration and heating rate of the solutions. Covalent

  4. 9-[4-(Azidomethylphenyl]-9H-carbazole-3-carbonitrile

    Directory of Open Access Journals (Sweden)

    C. Ramathilagam

    2014-02-01

    Full Text Available In the title compound C20H13N5, the dihedral angle between the carbazole ring system (r.m.s. deviation = 0.027 Å and the pendant benzene ring is 55.08 (6°. One of the azide N atoms is disordered over two positions in a 0.65 (2:0.35 (2 ratio. In the crystal, aromatic π–π stacking is observed [minimum centroid–centroid separation = 3.6499 (13 Å] as well as inversion-dimers connected by pairs of weak C—H...π interactions.

  5. Azido analogs of neuroactive steroids

    Czech Academy of Sciences Publication Activity Database

    Vidrna, Lukáš; Černý, Ivan; Pouzar, Vladimír; Borovská, Jiřina; Vyklický, Vojtěch; Vyklický ml., Ladislav; Chodounská, Hana

    2011-01-01

    Roč. 76, 10/11 (2011), s. 1043-1050. ISSN 0039-128X R&D Projects: GA MŠk(CZ) LC06077; GA MŠk(CZ) LC554; GA ČR(CZ) GA203/08/1498; GA ČR(CZ) GA309/07/0271 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : neuroactive steroids * synthesis * azides * NMDA receptor Subject RIV: CC - Organic Chemistry Impact factor: 2.829, year: 2011

  6. Ionization of covalent immobilized poly(4-vinylphenol) monolayers measured by ellipsometry, QCM and SPR

    International Nuclear Information System (INIS)

    Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surfaces followed by UV irradiation. The pH-responsive behavior of these PVP ultrathin films was evaluated by ellipsometry, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). By monitoring the responses of these films to pH in situ, the ionization constant of the monolayer thin films was obtained. The apparent pKa value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution

  7. -Phenoxo--pseudohalide and -pseudohalide dinuclear, tetranuclear and one-dimensional complexes: magneto-structural correlation and interesting type of solid state isomerism

    Indian Academy of Sciences (India)

    Sujit Sasmal; Sasankasekhar Mohanta

    2012-11-01

    Five Schiff base ligands have been utilized to explore metallo-pseudohalide (azide or cyanate) systems. These ligands are the 1:1 condensation products of 3-methoxysalicylaldehyde with ethanolamine (H2L1)/1-(2-aminoethyl)-piperidine (HL2)/ 4-(2-aminoethyl)-morpholine (HL3) or salicylaldehyde with 1-(2-aminoethyl)-piperidine (HL4)/4-(2-aminoethyl)-morpholine (HL5). The derived complexes are as follows: Four heterobridged -phenoxo-1,1-azide/cyanate dinickel(II) compounds of composition [Ni$^{\\text{II}}_{2}$ (HL1)3(1,1-N3)]$\\cdot$3H2O (1), [Ni$^{\\text{II}}_{2}$ (L2)2(1,1-N3)(N3)(H2O)]·CH3CH2OH (2), [Ni$^{\\text{II}}_{2}$ (L3)2-(1,1-N3)(CH3CN)(H2O)](ClO4)·H2O·CH3CN (3) and [Ni$^{\\text{II}}_{2}$ (HL1)3(1,1-NCO)]·2H2O (4); Two 1,3-azide bridged tetranickel(II) compounds [{NiII(L4)(1,3-N3)(H2O)}4] (5) and [{NiII(L5)(1,3-N3)(H2O)}4] (6); Two 1,3-azide/cyanate one-dimensional compounds [CuIIL5(1,3-NCO)]·2H2O (7) and [CuIIL5(1,3-N3)]·2H2O (8). Except compound 5 which shows overall antiferromagnetic coupling, other compounds exhibit overall ferromagnetic interaction. Syntheses, crystal structures, magnetic properties, density functional theoretical (DFT) calculations and experimental/theoretical magneto-structural correlations have been carried out which have revealed some interesting observations on composition/topology, magneto-structural correlations and solid state isomerism. The results have been already published. The present report deals with a review of the salient and interesting features of these works.

  8. Plasma membrane electron transport in frog blood vessels

    Indian Academy of Sciences (India)

    Rashmi P Rao; K Nalini; J Prakasa Rao

    2009-12-01

    In an attempt to see if frog blood vessels possess a plasma membrane electron transport system, the postcaval vein and aorta isolated from Rana tigrina were tested for their ability to reduce ferricyanide, methylene blue, and 2,6-dichloroindophenol. While the dyes remained unchanged, ferricyanide was reduced to ferrocyanide. This reduction was resistant to inhibition by cyanide and azide. Heptane extraction or formalin fixation of the tissues markedly reduced the capability to reduce ferricyanide. Denuded aortas retained only 30% of the activity of intact tissue. Our results indicate that the amphibian postcaval vein and aorta exhibit plasma membrane electron transport

  9. Shock Hugoniot and equations of states of water, castor oil, and aqueous solutions of sodium chloride, sucrose and gelatin

    Science.gov (United States)

    Gojani, A. B.; Ohtani, K.; Takayama, K.; Hosseini, S. H. R.

    2016-01-01

    This paper reports a result of experiments for the determination of reliable shock Hugoniot curves of liquids, in particular, at relatively low pressure region, which are needed to perform precise numerical simulations of shock wave/tissue interaction prior to the development of shock wave related therapeutic devices. Underwater shock waves were generated by explosions of laser ignited 10 mg silver azide pellets, which were temporally and spatially well controlled. Measuring temporal variation of shock velocities and over-pressures in caster oil, aqueous solutions of sodium chloride, sucrose and gelatin with various concentrations, we succeeded to determine shock Hugoniot curves of these liquids and hence parameters describing Tait type equations of state.

  10. Process for producing wurtzitic or cubic boron nitride

    International Nuclear Information System (INIS)

    Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described

  11. Benzimidazole-1,2,3-triazole Hybrid Molecules: Synthesis and Evaluation for Antibacterial/Antifungal Activity

    OpenAIRE

    Ouahrouch, Abdelaaziz; Ighachane, Hana; Taourirte, Moha; Joachim W. Engels; Sedra, My Hassan; Lazrek, Hassan B.

    2014-01-01

    A novel series of hybrid molecules 4a–i and 5a–i were prepared by condensation of 4-(trimethylsilylethynyl)benzaldehyde 1 with substituted o-phenylenediamines. These in turn were reacted with 2-(azidomethoxy)ethyl acetate in a Cu alkyne–azide cycloaddition (CuAAC) to generate the 1,2,3-triazole pharmacophore under microwave assistance. The newly synthesized compounds were examined for their in vitro antimicrobial activities against Gram-positive and Gram-negative bacteria and the phytopathoge...

  12. Adhesion of Lactobacillus amylovorus to Insoluble and Derivatized Cornstarch Granules

    OpenAIRE

    Imam, Syed H.; Harry-O'Kuru, R. E.

    1991-01-01

    Approximately 70% of the cells in a suspension of the amylolytic bacterium Lactobacillus amylovorus bind to cornstarch granules within 30 min at 25°C. More than 60% of the bound bacteria were removed by formaldehyde (2%) or glycine (1 M) at pH 2.0. More than 90% of the bound bacteria were removed by MgCl2 (2 M; pH 7.0). Binding of L. amylovorus to cornstarch was inhibited in heat-killed cells and in cells that had been pretreated with glutaraldehyde, formaldehyde, sodium azide, trypsin, or 1%...

  13. Synthesis, anti-microbial activity and molecular docking studies on triazolylcoumarin derivatives

    Indian Academy of Sciences (India)

    Chinnadurai Satheeshkumar; Mahalingam Ravivarma; Pandian Arjun; Vaithiyanathan Silambarasan; Nanjian Raaman; Devadasan Velmurugan; Changsik Song; Perumal Rajakumar

    2015-03-01

    A series of triazolylcoumarins was synthesized by the cycloaddition of acetylenic derivatives to azide in the presence of Cu(I) catalyst at room temperature. All the synthesized compounds were evaluated for their anti-microbial activity against Gram-positive (B. subtilis and S. aureus), Gram-negative bacteria (K. pneumonia and P. vulgaris) and human pathogenic fungi (C. tropicalis and C. krusei), with tetracycline and fluconazole as standards for anti-microbial and anti-fungal activity. Triazolylcoumarins exhibit anti-microbial activity against all the tested pathogens, which is further supported by molecular docking studies.

  14. Conjugates of boron clusters with derivatives of natural chlorin and bacteriochlorin

    International Nuclear Information System (INIS)

    Conjugates of bacteriochlorin p and chlorin e6 with cobalt bis(dicarbollide) anion [3,3'-Co(1,2-C2B9H11)2]- were synthesized using different synthetic approaches. The boronated bacteriochlorin p was prepared by reaction of bacteriochlorin N-amino cycloimide with, bis(dicarbollide)-based carboxylic acid. The boronated chlorin e6 conjugates were obtained by both 'click reaction' of containing alkyne group chlorine with azide derivative of cobaltacarborane and reaction of chorin-based amines with cyclic oxonium derivative of cobalt bis(dicarbollide).

  15. Synthesis of click-reactive HPMA copolymers using RAFT polymerization for drug delivery applications

    DEFF Research Database (Denmark)

    Ebbesen, Morten F; Schaffert, D.H.; Crowley, Michael L;

    2013-01-01

    This study describes a versatile strategy combining reversible addition fragmentation transfer (RAFT) polymerization and click chemistry to synthesize well-defined, reactive copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) for drug delivery applications. A novel azide containing monomer N-(3......-alkyne cycloaddition (CuAAC) was demonstrated by efficient conjugation (up to 92%) of phosphocholine, a near infrared dye, and poly(ethylene glycol) (PEG) with different substitution degrees, either alone or in combination. This study introduces a novel and versatile method to synthesize well-defined click-reactive...

  16. Temperature dependence of turnover in a Sc(OTf)3-catalyzed intramolecular Schmidt reaction

    Science.gov (United States)

    Fehl, Charlie; Hirt, Erin E.; Li, Sze-Wan; Aubé, Jeffrey

    2015-01-01

    The intramolecular Schmidt reaction of ketones and tethered azides is an efficient method for the generation of amides and lactams. This reaction is catalyzed by Lewis acids, which tightly bind the strongly basic amide product and result in product inhibition. We report herein conditions to achieve a catalytic Schmidt reaction using substoichiometric amounts of the heat-stable Lewis acid Sc(OTf)3. This species was shown to effectively release products of the Schmidt reaction in a temperature-dependent fashion. Thus, heat was able to promote catalyst turnover. A brief substrate scope was conducted using these conditions. PMID:26085693

  17. Efficient one-pot synthesis of amino-benzotriazolodiazocinone scaffolds via catalyst-free tandem Ugi-Huisgen reactions.

    Science.gov (United States)

    Barlow, T M A; Jida, M; Guillemyn, K; Tourwé, D; Caveliers, V; Ballet, S

    2016-05-18

    Herein we describe a catalyst-free, one-pot procedure employing an Ugi-4CR between propargyl glycine, functionalised 2-azidoanilines, different isocyanides and aldehydes, followed by a thermal azide-alkyne Huisgen cycloaddition to generate a 14-member set of amino-benzotriazolodiazocine-bearing dipeptides with multiple points of diversification and high atom economy. These structures were derivatized by means of Suzuki-Miyaura cross-coupling reactions at two positions with good to excellent yields, leading to conformationally constrained tricyclic structures. In silico and NMR conformational analysis studies demonstrated that turn conformations are adopted by these structures. PMID:27117259

  18. Stereospecific Synthesis of Substituted Aziridines by a Crystal-to-Crystal Photodenitrogenation of Δ(2)-1,2,3-Triazolines.

    Science.gov (United States)

    Chung, Tim S; Lopez, Steven A; Houk, K N; Garcia-Garibay, Miguel A

    2015-09-18

    Crystalline cis- or trans-Δ(2)-1,2,3-triazolines prepared by highly stereospecific and regioselective hydrogen bonding-catalyzed dipolar cycloaddition of activated cis- or trans-alkenes with aryl azides undergo a highly stereospecific photodenitrogenation to form the corresponding cis- or trans- azidirines in high chemical yields. While examples involving disubstituted and trisubstituted triazolines highlight steric challenges encountered in the dipolar cycloaddition reaction, the stereochemical control exerted by the crystalline lattice is enhanced by bulky substituents in the triazoline precursors to generate aziridines photochemically. PMID:26338467

  19. Polystyrene or Magnetic Nanoparticles as Support in Enantioselective Organocatalysis? A Case Study in Friedel-Crafts Chemistry.

    Science.gov (United States)

    Ranjbar, Sara; Riente, Paola; Rodríguez-Escrich, Carles; Yadav, Jagjit; Ramineni, Kishore; Pericàs, Miquel A

    2016-04-01

    Heterogenized versions of the second-generation MacMillan imidazolidin-4-one are described for the first time. This versatile organocatalyst has been supported on 1% DVB Merrifield resin and Fe3O4 magnetic nanoparticles through a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. The resulting catalytic materials have been successfully applied to the asymmetric Friedel-Crafts alkylation of indoles with α,β-unsaturated aldehydes. While both catalytic systems can be easily recovered and admit repeated recycling, the polystyrene-based catalyst shows higher stability and provides better stereoselectivities. PMID:27010999

  20. Di-μ-azido-κ4N1:N1-bis[(1,10-phenanthroline-κ2N,N′)(thiocyanato-κN)lead(II)

    OpenAIRE

    Gholamhossein Mohammadnezhad; Ali Reza Ghanbarpour; Amini, Mostafa M.; Seik Weng Ng

    2010-01-01

    In the centrosymmetric binuclear title compound, [Pb2(N3)2(NCS)2(C12H8N2)4], the N-donor atoms of one N-heterocycle and the N-donor atom of a thiocyanate anion along with the sterically active lone-pair electrons comprise an approximate square; a plane through three atoms of this square is twisted slightly with respect to the square made up of the other four atoms (two from the other N-heterocycle and one each from the bridging azide anions) at a dihedral angle of 18.7 (1)°...