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Sample records for pyrroles

  1. The Oxidation of Pyrrole.

    PubMed

    Howard, James K; Rihak, Kieran J; Bissember, Alex C; Smith, Jason A

    2016-01-01

    The dearomatization of heterocycles has been a powerful means for producing functional molecules in synthesis. In the case of pyrroles, reductive methods (such as the Birch reduction) have been most widely exploited, while oxidative methods are generally dismissed as too difficult or unpredictable to be useful. However, since the early twentieth century considerable research has been carried out on the controlled oxidation of pyrroles to give highly functionalized products, using a variety of oxidants. This review presents a summary of all work up until the present day in the area of pyrrole oxidation, looking at the use of peroxide, singlet oxygen, hypervalent iodine reagents, a range or organic and inorganic oxidants, and electrochemical approaches. It also offers some perspective on the potential future role of pyrrole oxidation in synthesis. PMID:26294175

  2. Electrochemical polymerization of pyrrole derivatives

    SciTech Connect

    Inagaki, T.; Hunter, M.; Yang, X.Q.; Skotheim, T.A.; Lee, H.S.; Okamoto, Y.

    1988-01-01

    Electrochemical copolymerization of pyrrole and 3-(6-ferrocenyl-6-hydroxyhexyl)pyrrole (P-Fc) yields a ferrocene functionalized polypyrrole with a controlled amount of ferrocene functionalization. Similarly, copolymers of pyrrole and 3-(4-(2,5- dimethoxyphenyl)butyl)pyrrole (P-MP) can be made by electrochemical polymerization and converted to the copolymers containing pH dependent electroactive hydroquinone moieties. 16 refs., 6 figs.

  3. A sustainable catalytic pyrrole synthesis

    NASA Astrophysics Data System (ADS)

    Michlik, Stefan; Kempe, Rhett

    2013-02-01

    The pyrrole heterocycle is a prominent chemical motif and is found widely in natural products, drugs, catalysts and advanced materials. Here we introduce a sustainable iridium-catalysed pyrrole synthesis in which secondary alcohols and amino alcohols are deoxygenated and linked selectively via the formation of C-N and C-C bonds. Two equivalents of hydrogen gas are eliminated in the course of the reaction, and alcohols based entirely on renewable resources can be used as starting materials. The catalytic synthesis protocol tolerates a large variety of functional groups, which includes olefins, chlorides, bromides, organometallic moieties, amines and hydroxyl groups. We have developed a catalyst that operates efficiently under mild conditions.

  4. Cyclo[n]pyrroles and methods thereto

    DOEpatents

    Sessler, Jonathan L.; Seidel, Daniel; Bolze, Frederic R.; Koehler, Thomas

    2006-01-10

    The present invention provides an oxidative coupling procedure that allows efficient synthesis of novel cyclo[n]pyrrole macrocycles. Therefore, the present invention provides cyclo[n]pyrroles where n is 6, 7, 8, 9, 10, 11, or 12, and derivatives, multimers, isomers, and ion and neutral molecule complexes thereof as new compositions of matter. A protonated form of cyclo[n]pyrrole displays a gap of up to 700 nm between strong Soret and Q-like absorption bands in the electronic spectrum, demonstrating no significant ground state absorption in the visible portion of the electronic spectrum. Uses of cyclo[n]pyrroles as separation media, nonlinear optical materials, information storage media and infrared filters are provided.

  5. Near ultraviolet photolysis of deuterated pyrrole.

    PubMed

    Cronin, Bríd; Devine, Adam L; Nix, Michael G D; Ashfold, Michael N R

    2006-08-01

    High resolution time-of-flight (TOF) measurements of the D atom fragments arising in the near ultraviolet (UV) photodissociation of deuterated pyrrole are reported. Structures evident in the measured TOF spectra are all interpretable in terms of N-D bond fission, and population of selected vibrational states of the pyrrolyl-d(4) co-fragment -- thereby clarifying previous uncertainties regarding the branching into different vibronic states of the pyrrolyl radical following UV excitation of pyrrole. PMID:16855723

  6. Resonantly enhanced multiphoton ionization of pyrrole, N-methyl pyrrole, and furan

    SciTech Connect

    Cooper, C.D.; Williamson, A.D.; Miller, J.C.; Compton, R.N.

    1980-08-15

    The resonantly enhanced multiphoton ionization (REMPI) spectra of pyrrole (C/sub 4/H/sub 5/N), N-methyl pyrrole (C/sub 5/H/sub 7/N), and furan (C/sub 4/H/sub 4/O) have been measured in the wavelength region from 365 to 680 nm. New and previously observed Rydberg states are reported for pyrrole and furan. Vibrational constants are presented for most of the Rydberg series. Accurate ionization potentials are derived for pyrrole (8.207 +- 0.003 eV) and N-methyl pyrrole (7.94 +- 0.02 eV). A strong two photon allowed transition is observed in N-methyl pyrrole at 41 193 cm/sup -1/ (0,0) and is attributed to an /sup 1/A/sub 2/ state. The corresponding state is not seen in pyrrole; however, it may be obscured by overlapping Rydberg series. Mass spectra following REMPI for benzene, pyrrole, and furan are reported. The degree of ionic fragmentation depends upon laser power density and wavelength.

  7. Experimental and DFT study on pyrrole tosylhydrazones

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam; Verma, Divya; Bharti, Shailendra Kumar

    2015-02-01

    Two pyrrole tosylhydrazones, 1H-pyrrole-2-tosylhydrazone (PT) and ethyl 3,5-dimethyl-4-(1-(2-tosylhydrazono)ethyl)-1H-pyrrole-2-carboxylate (EDTEPC) have been synthesized and characterized by various spectroscopic techniques. All calculations have been performed using B3LYP functional and 6-31G(d,p) basis set. The result of hydrogen bonding is obvious in 1H NMR and FT-IR due to down field chemical shift and vibrational red shift to pyrrole Nsbnd H proton, respectively. The red shift in both the proton donor (pyrrole Nsbnd H) and proton acceptor (Sdbnd O) group designates presence of intermolecular classical hydrogen bonding Nsbnd H⋯O. The binding energy of dimer formation is calculated as 13.12, 14.12 kcal/mol, after correction in basis set superposition error (BSSE). Topological parameters indicate the weaker interactions presents in the molecules. The global electrophilicity index (ω = 2.54, 2.28 eV) shows that PT and EDTEPC molecules are strong electrophile. The local reactivity descriptors analyses are performed to determine the reactive sites within the PT and EDTEPC. Computed first hyperpolarizability (β0 = 6.50/8.38 × 10-30 esu) of PT and EDTEPC indicates non-linear optical (NLO) response of the molecules.

  8. Flexible supercapacitor based on electrochemically synthesized pyrrole formyl pyrrole copolymer coated on carbon microfibers

    NASA Astrophysics Data System (ADS)

    Gholami, Mehrdad; Moozarm Nia, Pooria; Narimani, Leila; Sokhakian, Mehran; Alias, Yatimah

    2016-08-01

    The main objective of this work is to prepare a flexible supercapacitor using electrochemically synthesized pyrrole formyl pyrrole copolymer P(Py-co-FPy) coated on the carbon microfibers. Due to difficulties of working with carbon microfibers, glassy carbon was used to find out optimized conditions by varying mole ratio of pyrrole and formyl pyrrole monomers on the capacitance value. The prepared electrodes were characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), Brunauer-Emmett-Teller (BET) analysis, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Then the X-ray photoelectron spectroscopy (XPS) was used to characterize the optimized electrode. The specific capacitance is calculated using cyclic voltammetry, charge/discharge method, and impedance spectroscopy. The charge/discharge study reveals that the best specific capacitance is estimated to be 220.3 mF cm-2 for equal mole fraction of pyrrole and formyl pyrrole Py (0.1)-FP (0.1) at discharge current of 3 × 10-4 A. This optimized electrode keeps about 92% of its capacitance value in high current of discharging. The specific capacitances calculated by all the mentioned methods are in agreement with each other. Finally, the found optimized conditions were successfully applied to produce a flexible supercapacitor on the surface of carbon microfibers.

  9. Femtosecond Timescale Evolution of Pyrrole Electronic Excitation

    NASA Astrophysics Data System (ADS)

    Montero, Raul; Conde, Alvaro Peralta; Ovejas, Virginia; Castano, Fernando; Longarte, Asier

    2012-06-01

    Pyrrole is a simple aromatic molecule with relevantchromophoric properties in biology. Although its apparent simplicity, it shows a complicated dynamics after excitation in the near part of the UV absorption spectrum, which results from the interplay between the bright ππ^* and the dark dissociative πσ^* electronic transitions. Herein, we present a time resolved study with ultrafast resolution on the relaxation dynamics of isolated pyrrole, after excitation in the 265-217 nm range. Two lifetimes of 19 and 15 fs, which are associated with the internal conversion from the bright 1B2 ππ^* state and the propagation of the wavepacket on the πσ^* state, respectively, are found in the studied energy interval. The work also explores the consequences of non resonant adiabatic excitation of the system when broadband femtosecond pulses are employed to prepare the molecule in the targeted electronic states, revealing the key implication of this type of coherent phenomena. The collected data reveal that the bright 1B2 ππ^* state is adiabatically populated at excitation wavelengths far away from resonance, providing an efficient way to reach the πσ^* state. The recorded transients are fit employing a coherent model that provides a comprehensive view of the dynamical processes pyrrole undergoes after excitation by ultrashort light pulses. M. N. R. Ashfold, B. Cronin, A. L. Devine, R. N. Dixon and M. G. D. Nix Science, 312, 1637-1640, 2006.

  10. Photoejection of electrons from pyrrole into an aqueous environment: ab initio results on pyrrole-water clusters

    NASA Astrophysics Data System (ADS)

    Sobolewski, Andrzej L.; Domcke, Wolfgang

    2000-05-01

    Ab initio (RHF, CASSCF and CASPT2) calculations in the ground and lowest excited singlet states have been performed on pyrrole and pyrrole-water clusters. Full geometry optimization in the 1πσ ∗ state, which is energetically accessible from the optically allowed 1ππ ∗ state, reveals the flow of the electronic charge from pyrrole towards the water molecules, i.e., the formation of a charge transfer-to-solvent state. The computational results indicate that pyrrole-water clusters are good models for the investigation of the mechanistic details of the electron solvation process occurring upon ultraviolet photoexcitation of organic chromophores in liquid water.

  11. Morphology and electrical properties of electrochemically synthesized pyrrole-formyl pyrrole copolymer

    NASA Astrophysics Data System (ADS)

    Gholami, Mehrdad; Nia, Pooria Moozarm; Alias, Yatimah

    2015-12-01

    A direct electrochemical copolymerization of pyrrole-formyl pyrrole (Py-co-FPy) was carried out by oxidative copolymerization of formyl pyrrole and pyrrole in LiClO4 aqueous solution through galvanostatic method. The (Py-co-FPy) copolymer was characterized using Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), energy-filtering transmission electron microscope (EFTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FESEM images showed that the synthesized copolymer had a hollow whelk-like helixes structure, which justifies the enhancement of charge transportation through the copolymer film. Cyclic voltammetry studies revealed that the electrocatalytic activity of synthesized copolymer has improved and the surface coverage in copolymer enhanced 1.6 times compared to polypyrrole alone. Besides, (Py-co-FPy) copolymer showed 2.5 times lower electrochemical charge transfer resistance (Rct) value in impedance spectroscopy. Therefore, this copolymer has a strong potential to be used in several applications such as sensor applications.

  12. Living on pyrrolic foundations - Advances in natural and artificial bioactive pyrrole derivatives.

    PubMed

    Domagala, Anna; Jarosz, Tomasz; Lapkowski, Mieczyslaw

    2015-07-15

    Pyrrole, a simple heterocyclic system, is an important building block for numerous biologically active compounds both natural and synthetic in origin, which boast an immense array of qualities, baleful and beneficial alike. The latter have given rise to a bountiful variety of pyrrole-based drugs, with many more being designed, developed and applied each year, as evidenced by the amount of entries in the Cambridge Structural Database skyrocketing from about six hundred in 2004 to more than a thousand over the course of the last decade. Particularly important in light of the ever-encroaching menace of drug-resistant bacteria, the vast progress in the field necessitates a sound organisational framework and summary - a task, to which we contribute this summary and checklist of the most recent developments, indicating the classes of compounds, which have attracted the most significant research attention. PMID:26087028

  13. Hydroquinone-pyrrole dyads with varied linkers.

    PubMed

    Huang, Hao; Karlsson, Christoffer; Strømme, Maria; Sjödin, Martin; Gogoll, Adolf

    2016-01-01

    A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from (1)H NMR, (13)C NMR, and UV-vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO-LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices. PMID:26877811

  14. Hydroquinone–pyrrole dyads with varied linkers

    PubMed Central

    Huang, Hao; Karlsson, Christoffer; Strømme, Maria; Sjödin, Martin

    2016-01-01

    Summary A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices. PMID:26877811

  15. Simple two-step synthesis of 2,4-disubstituted pyrroles and 3,5-disubstituted pyrrole-2-carbonitriles from enones

    PubMed Central

    Kucukdisli, Murat; Ferenc, Dorota; Heinz, Marcel; Wiebe, Christine

    2014-01-01

    Summary The cyclocondensation of enones with aminoacetonitrile furnishes 3,4-dihydro-2H-pyrrole-2-carbonitriles which can be readily converted to 2,4-disubstituted pyrroles by microwave-induced dehydrocyanation. Alternatively, oxidation of the intermediates produces 3,5-disubstituted pyrrole-2-carbonitriles. PMID:24605166

  16. Electrogenerated poly(pyrrole-lactosyl) and poly(pyrrole-3'-sialyllactosyl) interfaces: toward the impedimetric detection of lectins

    PubMed Central

    Gondran, Chantal; Dubois, Marie-Pierre; Fort, Sébastien; Cosnier, Serge

    2013-01-01

    This paper reports on the impedimetric transduction of binding reaction between polymerized saccharides and target lectins. The controlled potential electro-oxidation of pyrrole-lactosyl and pyrrole-3′-sialyllactosyl at 0.95 V vs. Ag/AgCl, provides thin and reproducible poly(pyrrole-saccharide) films. The affinity binding of two lectins: Arachis hypogaea, (PNA) and Maackia amurensis (MAA) onto poly(pyrrole-lactosyl) and poly(pyrrole-3′-sialyllactosyl) electrodes, was demonstrated by cyclic voltammetry in presence of ruthenium hexamine and hydroquinone. In addition, rotating disk experiments were carried out to determine the permeability of both polypyrrole films and its evolution after incubating with lectin target. Finally, the possibility of using the poly(pyrrole-lactosyl) or poly(pyrrole-3′-siallyllactosyl) films for the impedimetric transduction of the lectin binding reaction, was investigated with hydroquinone (2 × 10−3 mol L−1) as a redox probe in phosphate buffer. The resulting impedance spectra were interpreted and modeled as an equivalent circuit indicating that charge transfer resistance (Rct) and relaxation frequency (f°) parameters are sensitive to the lectin binding. Rct increases from 77 to 97 Ω cm2 for PNA binding and from 93 to 131 Ω cm2 for MAA binding. In parallel, f° decreases from 276 to 222 Hz for PNA binding and from 223 to 131 Hz for MAA binding. This evolution of both parameters reflects the steric hindrances generated by the immobilized lectins towards the permeation of the redox probe. PMID:24790939

  17. Electrogenerated poly(pyrrole-lactosyl) and poly(pyrrole-3'-sialyllactosyl) interfaces: towards the impedimetric detection of lectins

    NASA Astrophysics Data System (ADS)

    Gondran, Chantal; Dubois, Marie-Pierre; Fort, Sebastien; Cosnier, Serge

    2013-07-01

    This paper reports on the impedimetric transduction of binding reaction between polymerized saccharides and target lectins. The controlled potential electro-oxidation of pyrrole-lactosyl and pyrrole-3’-sialyllactosyl at 0.95 V vs Ag/AgCl, provides thin and reproducible poly(pyrrole-saccharide) films. The affinity binding of two lectins: Arachis hypogaea, (PNA) and Maackia amurensis (MAA) onto poly(pyrrole-lactosyl) and poly(pyrrole-3’-sialyllactosyl) electrodes, was demonstrated by cyclic voltammetry in presence of ruthenium hexamine and hydroquinone. In addition, rotating disk experiments were carried out to determine the permeability of both polypyrrole films and its evolution after incubating with lectin target. Finally, the possibility of using the poly(pyrrole-lactosyl) or poly(pyrrole-3’-siallyllactosyl) films for the impedimetric transduction of the lectin binding reaction, was investigated with hydroquinone (2×10-3 mol L-1) as a redox probe in phosphate buffer. The resuting impedance spectra were interpreted and modeled as an equivalent circuit indicating that charge transfer resistance (Rct) and relaxation frequency (f°) parameters are sensitive to the lectin binding. Rct increases from 77 to 97 Ω cm2 for PNA binding and from 93 to 131 Ω cm2 for MAA binding. In parallel, f° decreases from 276 to 222 Hz for PNA binding and from 223 to 131 Hz for MAA binding. This evolution of both parameters reflects the steric hindrances generated by the immobilised lectins towards the permeation of the redox probe.

  18. Selective Mono-reduction of Pyrrole-2,5 and 2,4-Dicarboxylates.

    PubMed

    Yasui, Eiko; Tsuda, Jyunpei; Ohnuki, Satoshi; Nagumo, Shinji

    2016-01-01

    Pyrrole-2,5-dicarboxylates were rapidly and selectively reduced to the corresponding mono-alcohol using 3 eq of diisobutylaluminum hydride at 0°C. Pyrrole-2,4-dicarboxylate showed the same reactivity; however, the selectivity decreased with pyrrole-3,4-dicarboxylate. When the nitrogen atom of the pyrrole-2,5-dicarboxylate is protected with a benzyl group, selective mono-reduction does not occur. Considering that furan-2,5-dicarboxylates did not give the corresponding mono-alcohol under the same conditions, the unprotected nitrogen atom of pyrrole apparently plays an important role in this selective mono-reduction. PMID:27581630

  19. Towards the Synthesis of Dihydrooxepino[4,3-b]pyrrole-Containing Natural Products via Cope Rearrangement of Vinyl Pyrrole Epoxides.

    PubMed

    Cameron, Alex; Fisher, Brendan; Fisk, Nicholas; Hummel, Jessica; White, Jonathan M; Krenske, Elizabeth H; Rizzacasa, Mark A

    2015-12-18

    An approach to the dihydrooxepino[4,3-b]pyrrole core of diketopiperazine natural products which utilizes a vinyl pyrrole epoxide Cope rearrangement was investigated. It was found that an ester substituent on the epoxide was essential for the [3,3]-rearrangement to occur. Density functional calculations with M06-2X provided explanations for the effects of the pyrrole and ester groups on these rearrangements. PMID:26629727

  20. Efficient syntheses of permethylated derivatives of neolamellarin A, a pyrrolic marine natural product

    NASA Astrophysics Data System (ADS)

    Yin, Ruijuan; Jiang, Long; Wan, Shengbiao; Jiang, Tao

    2015-04-01

    The pyrrole-derived alkaloids with marine origin, especially their permethyl derivatives, have unique structures and promising biological activities. Marine natural product neolamellarins are a collection of lamellarin-like phenolic pyrrole compounds, which can inhibit hypoxia-induced HIF-1 activation. Many pyrrole-derived lamellarin-like alkaloids show potent MDR reversing activity. In this study, five permethylated derivatives of neolamellarin A were synthesized with their MDR reversing activity studied in order to identify new MDR reversal agents. A convergent strategy was adopted to synthesize the permethylated derivatives of neolamellarin A. Pyrrole was first converted into a corresponding N-trisisopropylsilyl (TIPS)-substituted derivative, then through iodination afforded 3,4-diiodinated pyrrole compound. The key intermediate, 3,4-disubstituent-1 H-pyrrole, was obtained through desilylation of 3,4-disubstituent-1-TIPS pyrrole, which was prepared from 3,4-diiodinated pyrrole derivative and aryl boronic acid ester through Suzuki cross-coupling reaction between them. Then, the intermediate, 3,4-disubstituent-1 H-pyrrole, reacted with fresh phenylacetyl chloride under n-BuLi/THF condition afforded the target compounds. Finally, we obtained five novel pyrrolic compounds, permethylated derivatives of neolamellarin A 16a-e, in 30%-37% yield through five step reactions. The bioactivity testing of these compounds are in process.

  1. Calix[4]pyrrole-based ion pair receptors.

    PubMed

    Kim, Sung Kuk; Sessler, Jonathan L

    2014-08-19

    Ion pair receptors, which are able to bind concurrently both a cation and an anion, often display higher selectivity and affinity for specific ion pairs than simple ion receptors capable of recognizing primarily either a cation or an anion. This enhancement in recognition function is attributable to direct or indirect cooperative interactions between cobound ions via electrostatic attractions between oppositely charged ions, as well as to positive allosteric effects. In addition, by virtue of binding the counterions of the targeted ion, ion pair receptors can minimize the solvation of the counterions, which can otherwise have a negative effect on the interactions between the receptors and the targeted ions. As a result of their more favorable interactions, ion pair receptors are attractive for use in applications, such as extraction and sensing, where control of the binding interactions is advantageous. In this Account, we illustrate this potential in the context of ion pair receptors based on the calix[4]pyrrole scaffold. Both simple ditopic ion pair receptors, containing sites for the recognition of a single anion and single cation, and so-called multitopic ion pair receptors will be discussed. The latter systems differ from conventional, so-called ditopic ion pair receptors in that they contain more than one binding site for a given targeted ion (e.g., a cation). This permits a level of selectivity and control over binding function not normally seen for simple ion or ion pair receptors containing one or two binding sites, respectively. Calix[4]pyrroles are macrocyclic compounds consisting of four pyrrole units linked via fully substituted sp(3) hybridized meso carbon atoms. They are effective receptors for Lewis basic anions (e.g., halides) in typical organic media and under certain conditions will recognize ion pairs containing charge diffuse cations, such as a small alkylammonium, imidazolium, or cesium cations. The calix[4]pyrrole framework is further

  2. Sensing of antipyretic carboxylates by simple chromogenic calix[4]pyrroles.

    PubMed

    Nishiyabu, Ryuhei; Anzenbacher, Pavel

    2005-06-15

    We present a simple, two- or three-step method for the synthesis of chromogenic octamethylcalix[4]pyrrole-based (OMCP) sensors for anions. Electrophilic aromatic substitution allows for converting the pyrrole moieties of OMCP into a dye. The formation of a sensor-anion complex results in partial charge transfer and a dramatic change in color. The absorption (UV-vis) and NMR titration experiments show that the chromogenic OMCPs sense anions administered as aqueous solutions, even at high ionic strength ( approximately 0.1 M NaCl), while displaying selectivity for pyrophosphate and carboxylate anions. The experiments with polyurethane sensor films show a strong response for aqueous carboxylates, such as antipyretics naproxen approximately ibuprofen > salicylate, without being biased by bicarbonate or carboxy termini of blood plasma proteins. PMID:15941245

  3. Oxoanion Recognition by Benzene-based Tripodal Pyrrolic Receptors

    SciTech Connect

    Bill, Nathan; Kim, Dae-Sik; Kim, Sung Kuk; Park, Jung Su; Lynch, Vincent M.; Young, Neil J; Hay, Benjamin; Yang, Youjun; Anslyn, Eric; Sessler, Jonathan L.

    2012-01-01

    Two new tripodal receptors based on pyrrole- and dipyrromethane-functionalised derivatives of a sterically geared precursor, 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene, are reported; these systems, compounds 1 and 2, display high affinity and selectivity for tetrahedral anionic guests, in particular dihydrogen phosphate, pyrophosphate and hydrogen sulphate, in acetonitrile as inferred from isothermal titration calorimetry measurements. Support for the anion-binding ability of these systems comes from theoretical calculations and a single-crystal X-ray diffraction structure of the 2:2 (host:guest) dihydrogen phosphate complex is obtained in the case of the pyrrole-based receptor system, 1. Keywords anion receptors, dihydrogen phosphate, hydrogen sulphate, X-ray structure, theoretical calculations.

  4. Poly(pyrrole)/MoS{sub 2} intercalation compounds

    SciTech Connect

    Wang, L.; Kanatzidis, M.G.

    1995-12-31

    It is known that polymer/MoS{sub 2} intercalation compounds can be prepared through methods such as polymerizing intercalated monomers in MoS{sub 2} or mixing a polymer solution with MoS{sub 2} single layers suspended in water. The latter method is easy to perform, but can only be applied to soluble polymers. We have developed an in-situ polymerization-encapsulation method which was used to insert poly(pyrrole), an insoluble conjugated polymer, into MoS{sub 2}. Synthesis, characterization and electrical properties of the poly(pyrrole)/MoS{sub 2} materials, prepared by this method, will be presented and compared with other related lamellar systems.

  5. Microwave-Assisted Piloty-Robinson Synthesis of 3,4-Disubstituted Pyrroles

    PubMed Central

    Milgram, Benjamin C.; Eskildsen, Katrine; Richter, Steven M.; Scheidt, W. Robert; Scheidt, Karl A.

    2007-01-01

    The synthesis of N-acyl 3,4-disubstituted pyrroles can be accomplished directly from hydrazine and an aldehyde via a Piloty-Robinson pyrrole synthesis. The use of microwave radiation for the cyclization and pyrrole formation greatly reduces the time necessary for this process and facilitates moderate to good yields from hydrazine for the corresponding 3,4-disubstituted products (5–12). By simple hydrolysis, the free N–H pyrroles can be accessed after the Piloty-Robinson reaction and then used directly in the synthesis of octaethylporphyrin (H2OEP, 14) and octaethyltetraphenylporphyrin (H2OETPP, 15). PMID:17432915

  6. Poly(pyrrole-co-pyrrole propylic acid) film and its application in label-free surface plasmon resonance immunosensors.

    PubMed

    Hu, Weihua; Li, Chang Ming; Dong, Hua

    2008-12-01

    In this work, surface plasmon resonance (SPR) was used to study protein immobilization on poly(pyrrole-co-pyrrole propylic acid) (PPy/PPa) for immunosensing applications. SPR was employed to in situ monitor the electropolymerization process and to control thickness of the PPy/PPa copolymer film. Goat IgG as a model protein was covalently immobilized on the carboxyl-containing film through EDC/NHS as the coupling reagents. The effect of pyrrole propylic acid (Pa) proportion in the deposition solution on the protein immobilization capability was systemically investigated. The immobilization efficiency was demonstrated by a label-free SPR immunosensor. The heterogeneous kinetics of the immune reaction was discussed. This work could provide a facile method to immobilize proteins on an electrode surface by electropolymerized copolymer, and renders a universal approach to in situ study the protein immobilization process and sensing kinetics for scientific insights of the heteroimmunosensing scheme particularly in surface chemistry and molecular biology for further improvement of immunosensors. PMID:19068327

  7. Merging gold and organocatalysis: a facile asymmetric synthesis of annulated pyrroles.

    PubMed

    Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

    2014-04-01

    The combination of cinchona-alkaloid-derived primary amine and Au(I) -phosphine catalysts allowed the selective C-H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. PMID:24590817

  8. Nucleophilic addition of sulfonamides to bromoacetylenes: facile preparation of pyrroles.

    PubMed

    Yamagishi, Masahito; Nishigai, Ken; Hata, Takeshi; Urabe, Hirokazu

    2011-09-16

    Nucleophilic addition of sulfonamides to 1-bromo-1-alkynes provided (Z)-N-(1-bromo-1-alken-2-yl)-p-toluenesulfonamides in good yield and in a highly regio- and stereoselective manner. Treatment of product (Z)-N-(1-bromo-1-octen-2-yl)-N-allyl-p-toluenesulfonamide with a palladium catalyst under Heck conditions afforded 1-(p-toluenesulfonyl)-2-hexyl-4-methylpyrrole in good yield. Other pyrroles with various substituents can also be prepared in good yield by this method. PMID:21842873

  9. Hybrid Pyrrole-Imidazole Alkaloids from the Sponge Agelas sceptrum.

    PubMed

    Muñoz, Julie; Köck, Matthias

    2016-02-26

    A chemical investigation of the tropical sponge Agelas sceptrum from Plana Cays (Bahamas) led to the isolation of two hybrid pyrrole-imidazole alkaloids (PIAs), 15'-oxoadenosceptrin (1) and decarboxyagelamadin C (2). Herein, we report their challenging structure elucidation established by NMR and ECD spectroscopy. 15'-Oxoadenosceptrin (1) shows sceptrin merged with an adenine moiety, not yet encountered in the PIA family, whereas decarboxyagelamadin C (2) is a close derivative of agelamadins C to E recently isolated from an Agelas sp. from Okinawa. PMID:26872204

  10. Decarboxylation of pyrrole-2-carboxylic acid: A DFT investigation

    NASA Astrophysics Data System (ADS)

    Cheng, Xueli; Wang, Jinhu; Tang, Ke; Liu, Yongjun; Liu, Chengbu

    2010-08-01

    Decarboxylation is normally a dissociative process, commonly catalyzed by proton or enzymes. The decarboxylation mechanism of pyrrole-2-carboxylic acid involves the addition of water to the carboxyl group, and the C-C bond cleavage leading to the protonated carbonic acid. The direct decarboxylation and decarboxylation aided with water were also investigated to consider the functions of proton and water. Our calculations with G AUSSIAN 03 package show that, with the assistance of H 3O +, the potential energy of the C-C rupture decreases significantly to 9.77 kcal/mol, and the total energy barrier decreases to 33.99 kcal/mol.

  11. Spectroscopic and spectrometric studies of anion recognition with calix[4]pyrroles in different reaction conditions

    NASA Astrophysics Data System (ADS)

    Giri, Nand Gopal; Chauhan, Shive Murat Singh

    2009-09-01

    The binding studies of calix[4]pyrroles ( 1- 6) with fluoro, chloro, bromo, iodo and sulphato anions generated from normal-tetrabutylammoniumfluoride, normal-tetrabutylammoniumchloride, normal-tetrabutylammoniumbromide, normal-tetrabutylammoniumiodide, and normal-tetrabutylammoniumsulphate respectively were investigated by electrospray ionization mass spectrometry (ESI-MS) in dichloromethane-acetonitrile in negative ion mode. The efficacy of a particular calix[4]pyrrole to bind with anions was found maximum at low cone voltage of the instrument, at high cone voltage the binding was suppressed due to removal of anion from the cavity of the macrocycles. The binding strength was found inversely proportional to the size of anion for a particular calix[4]pyrrole. The fragmentation pattern of calix[4]pyrrole was observed at higher cone voltage of ESI-MS and was interpreted. The association constants of calix[4]pyrroles and anions obtained from electronic transition studies were in good agreement with that observed from 1H NMR titration studies.

  12. Biofunctionalization of multiwalled carbon nanotubes by electropolymerized poly(pyrrole-concanavalin A) films.

    PubMed

    Papper, Vladislav; Elouarzaki, Kamal; Gorgy, Karine; Sukharaharja, Ayrine; Cosnier, Serge; Marks, Robert S

    2014-10-13

    The synthesis and electropolymerization of a pyrrolic concanavalin A derivative (pyrrole-Con A) onto a multiwalled carbon nanotube (MWCNT) deposit is reported. Glucose oxidase was then immobilized onto the MWCNT-poly(pyrrole-Con A) coating by affinity carbohydrate interactions with the polymerized Con A protein. The resulting enzyme electrode was applied to the amperometric detection of glucose exhibiting a high sensitivity of 36 mA cm(-2) mol(-1) L and a maximum current density of 350 μA cm(-2) . PMID:25179428

  13. Synthesis of two distinct pyrrole moiety-containing arenes from nitroanilines using Paal-Knorr followed by an indium-mediated reaction.

    PubMed

    Kim, Byeong Hyo; Bae, Seolhee; Go, Ahra; Lee, Hyunseung; Gong, Cheoloh; Lee, Byung Min

    2016-01-01

    Synthesis of arenes substituted with two differently substituted-pyrrole moieties was investigated. A Paal-Knorr condensation reaction of nitroanilines with 1,4-diketone to nitrophenyl-1H-pyrroles followed by an indium-mediated reduction-triggered coupling reaction with another kind of 1,4-diketone resulted in two distinct pyrrole-containing arenes, variously substituted 1-((1H-pyrrol-1-yl)phenyl)-1H-pyrroles, in reasonable yield. PMID:26593044

  14. Antitumor activity of a pyrrole-imidazole polyamide

    PubMed Central

    Yang, Fei; Nickols, Nicholas G.; Li, Benjamin C.; Marinov, Georgi K.; Said, Jonathan W.; Dervan, Peter B.

    2013-01-01

    Many cancer therapeutics target DNA and exert cytotoxicity through the induction of DNA damage and inhibition of transcription. We report that a DNA minor groove binding hairpin pyrrole-imidazole (Py-Im) polyamide interferes with RNA polymerase II (RNAP2) activity in cell culture. Polyamide treatment activates p53 signaling in LNCaP prostate cancer cells without detectable DNA damage. Genome-wide mapping of RNAP2 binding shows reduction of occupancy, preferentially at transcription start sites, but occupancy at enhancer sites is unchanged. Polyamide treatment results in a time- and dose-dependent depletion of the RNAP2 large subunit RPB1 that is preventable with proteasome inhibition. This polyamide demonstrates antitumor activity in a prostate tumor xenograft model with limited host toxicity. PMID:23319609

  15. Experimental and theoretical study of 4-formyl pyrrole derived aroylhydrazones

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-03-01

    Two new 4-formyl pyrrole derived aroylhydrazones (3a, b) from ethyl 4-formyl-3,5-dimetyl-1H-pyrrole-2-carboxylate and aroylhydrazides (3,5-dinitrobenzohydrazide/2-hydrazinocarbonyl-N-phenyl-acetamide) have been synthesized and characterized by various spectroscopic techniques 1H NMR, Mass, UV-Visible and FT-IR. The calculated thermodynamic parameters show that the formation of 3a as spontaneous, whereas 3b as non-spontaneous. TD-DFT has been used to calculate the absorption wavelengths, oscillator strength (f) and the nature of electronic excitations. Natural bond orbital (NBO) analysis has been carried out to explore the various conjugative and hyperconjugative interactions and their second order stabilization energy (E(2)) within monomer and its dimer. The dimer formation of 3a, 3b due to result of intermolecular hydrogen bonding N1sbnd H30⋯O84, N1sbnd H28⋯O60 is obvious in 1H NMR, NBO and FT-IR as down field chemical shifts, n(O84) → σ∗(N1sbnd H30), n(O60) → σ∗(N1sbnd H28) interactions, vibrational red shifts, respectively. To determine the strength and nature of hydrogen bonding, topological parameters at bond critical points (BCP) have been analyzed by 'Quantum theory of Atoms in molecules' (QTAIM) in detail. The global electrophilicity index (ω) has been calculated to determine the relative electrophilic strength of molecules. The local reactivity descriptors analyses such as Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) have been performed to determine the reactive sites within molecules. The first hyperpolarizabilities (β0) of 3a, b have been computed to evaluate the non-linear optical (NLO) response of the investigated molecules.

  16. Recent developments in the group-1B-metal-catalyzed synthesis of pyrroles.

    PubMed

    Zhou, Ni-Ni; Zhu, Hai-Tao; Yang, De-Suo; Guan, Zheng-Hui

    2016-07-26

    Pyrroles are important synthetic targets as a result of their occurrence in numerous biologically active molecules, their important roles in diverse living processes, and their utility as versatile intermediates. As a consequence, numerous efforts focused on the development of concise and efficient methods for the construction of pyrroles. Compared with other transition metals, the group 1B metals (Cu, Ag and Au) are probably more versatile and widely used for the synthesis of pyrroles in organic chemistry. Considering the importance of both topics in organic synthesis, here we summarize recent achievements in the synthesis of pyrroles catalyzed by monometallic systems which belong to the group 1B metals (Cu, Ag and Au). PMID:27345290

  17. Discovery of pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase.

    PubMed

    Bratton, Larry D; Auerbach, Bruce; Choi, Chulho; Dillon, Lisa; Hanselman, Jeffrey C; Larsen, Scott D; Lu, Gina; Olsen, Karl; Pfefferkorn, Jeffrey A; Robertson, Andrew; Sekerke, Catherine; Trivedi, Bharat K; Unangst, Paul C

    2007-08-15

    In an effort to identify hepatoselective inhibitors of HMG-CoA reductase, two series of pyrroles were synthesized and evaluated. Efforts were made to modify (3R,5R)-7-[3-(4-fluorophenyl)-1-isopropyl-4-phenyl-5-phenylcarbamoyl-1H-pyrrol-2-yl]-3,5-dihydroxy-heptanoic acid sodium salt 30 in order to reduce its lipophilicity and therefore increase hepatoselectivity. Two strategies that were explored were replacement of the lipophilic 3-phenyl substituent with either a polar function (pyridyl series) or with lower alkyl substituents (lower alkyl series) and attachment of additional polar moieties at the 2-position of the pyrrole ring. One compound was identified to be both highly hepatoselective and active in vivo. We report the discovery, synthesis, and optimization of substituted pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase for reducing low density lipoprotein cholesterol (LDL-c) in the treatment of hypercholesterolemia. PMID:17560788

  18. Pd-Catalyzed C-H Bond Functionalization on the Indole and Pyrrole Nucleus

    NASA Astrophysics Data System (ADS)

    Beck, Elizabeth M.; Gaunt, Matthew J.

    This review details recent developments in the Pd-catalyzed C-H bond arylation and alkenylation of indoles and pyrroles, aromatic heterocycles that are frequently displayed in natural products and medicinal agents.

  19. Synthesis and biological activity of pyrrole analogues of combretastatin A-4.

    PubMed

    Jung, Eun-Kyung; Leung, Euphemia; Barker, David

    2016-07-01

    A series of pyrrole analogues of combretastatin (CA-4) were synthesized and tested for their anti-proliferative activity. The highly diastereoselective acyl-Claisen rearrangement was used to provide 2,3-syn disubstituted morpholine amides which were used as precursors for the various analogues. This synthesis allows for the preparation of 1,2- and 2,3-diaryl-1H-pyrroles which are both geometrically similar to CA-4. These pyrrolic analogues were tested for their anti-proliferative activity against two human cell lines, K562 and MDA-MB-231 with 2,3-diaryl-1H-pyrrole 35 exhibiting the most potent activity with IC50 value of 0.07μM against MDA-MB-231 cell line. PMID:27212068

  20. A Photoinduced Cobalt-Catalyzed Synthesis of Pyrroles through in Situ-Generated Acylazirines.

    PubMed

    Pusch, Stefan; Kowalczyk, Danuta; Opatz, Till

    2016-05-20

    Tetrasubstituted pyrroles can be synthesized in a one-pot procedure from isoxazoles. The process includes the photoinduced in situ formation of acylazirines combined with a subsequent cobalt(II)-catalyzed ring expansion with 1,3-diketones. PMID:27081704

  1. Bipyrrole-Strapped Calix[4]pyrroles: Strong Anion Receptors That Extract the Sulfate Anion

    SciTech Connect

    Kim, Sung Kuk; Lee, Juhoon; Williams, Neil J; Lynch, Vincent M.; Hay, Benjamin; Moyer, Bruce A; Sessler, Jonathan L.

    2014-01-01

    Cage-type calix[4]pyrroles 2 and 3 bearing two additional pyrrole groups on the strap have been synthesized. Compared with the parent calix[4]pyrrole (1), they were found to exhibit remarkably enhanced affinities for anions, including the sulfate anion (TBA+ salts), in organic media (CD2Cl2). This increase is ascribed to participation of the bipyrrole units in anion binding. Receptors 2 and 3 extract the hydrophilic sulfate anion (as the methyltrialkyl(C8-10)ammonium (A336+) salt)) from aqueous media into a chloroform phase with significantly improved efficiency (>10-fold relative to calix[4]pyrrole 1). These two receptors also solubilize into chloroform the otherwise insoluble sulfate salt, (TMA)2SO4 (tetramethylammonium sulfate).

  2. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    SciTech Connect

    Advanced Light Source; Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; England, Alice H.; Prendergast, David; Saykally, Richard J

    2009-05-29

    Near edge x-ray absorption fine structure (NEXAFS) spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  3. The synthesis of pyrroles and oxazoles based on gold α-imino carbene complexes.

    PubMed

    Loy, Nicole S Y; Choi, Subin; Kim, Sunggak; Park, Cheol-Min

    2016-05-31

    Cationic gold complexes of α-oximimino carbenes have been identified to react with weak nucleophiles including enol ethers and nitriles. These findings allowed us to develop the highly efficient synthesis of pyrroles and oxazoles. PMID:27152984

  4. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    SciTech Connect

    Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; England, Alice H.; Saykally, Richard J.; Prendergast, David

    2009-09-21

    Near edge x-ray absorption fine structure spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  5. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; England, Alice H.; Prendergast, David; Saykally, Richard J.

    2009-09-01

    Near edge x-ray absorption fine structure spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  6. Theoretical study of structure and electronic properties of cyano-substituted pyrroles

    NASA Astrophysics Data System (ADS)

    Rimarčík, Ján; Lukeš, Vladimír; Klein, Erik; Griesser, Markus; Kelterer, Anne-Marie

    2008-11-01

    DFT and ab initio MP2 calculations of optimal geometries, dipole moments, polarizabilities, excitation energies and enthalpies of hydrogen or proton transfer from N-H group for cyano derivatives of pyrrole are presented. CN groups in α and β positions have distinct effects on electron spectra absorption bands. CN in α position causes larger bathochromic shift in comparison to β position. N-H bond dissociation enthalpies (BDE) of substituted pyrroles are higher by 7 kJ mol -1 than pyrrole BDE. Number and position of CN groups do not affect BDEs. Proton affinities of pyrrolyl anions and enthalpies of electron transfer from these anions are proportional to the number of CN groups in molecule. Each CN group causes decrease in proton affinity by 72 kJ mol -1 and 73 kJ mol -1 rise in electron transfer enthalpy. For several studied pyrroles, BDEs, proton affinities and electron transfer enthalpies in water and benzene were computed.

  7. Excited state dynamics in pyrrole water clusters: First-principles simulation

    NASA Astrophysics Data System (ADS)

    Frank, Irmgard; Damianos, Konstantina

    2008-01-01

    The excited state dynamics in pyrrole-water clusters is investigated using restricted open-shell Kohn-Sham theory. While the isolated pyrrole molecule dissociates in the excited state, no dissociation is observed in the presence of water molecules. Instead an electron is transferred to water and moves as solvated electron between the water molecules. The results are compared to data obtained from other first-principles and ab initio calculations.

  8. Probing and evaluating anion-π interaction in meso-dinitrophenyl functionalized calix[4]pyrrole isomers.

    PubMed

    Kim, Ajeong; Ali, Rashid; Park, Seok Ho; Kim, Yong-Hoon; Park, Jung Su

    2016-09-25

    We investigate anion-π binding modes in a cis-isomer of 3,5-dinitrophenyl-substituted calix[4]pyrrole with various anions via X-ray crystallographic analyses and compare its binding affinities with those of the corresponding trans-isomer. Sandwich-type anion-π interactions prove to not only enhancing anion binding abilities but also altering the anion-binding selectivity of the calix[4]pyrrole framework. PMID:27549578

  9. Calix[4]pyrroles: highly selective stationary phases for gas chromatographic separations.

    PubMed

    Fan, Jing; Wang, Zhenzhong; Li, Qian; Qi, Meiling; Shao, Shijun; Fu, Ruonong

    2014-10-01

    Calix[4]pyrroles offer a great potential as stationary phases for gas chromatography (GC) due to their unique structures and physicochemical properties. Herein we present the first report of using two calix[4]pyrroles, namely meso-tetra-cyclohexylcalix[4]pyrrole (THCP) and meso-octamethylcalix[4]pyrrole (OMCP). These stationary phases were statically coated onto capillary columns and investigated in terms of column efficiency, polarity, separation performance, thermal stability and repeatability. The columns achieved column efficiencies of 2200-3000plates/m and exhibited nonpolar nature with an average polarity of 67 for THCP and 64 for OMCP, respectively. THCP stationary phase shows high selectivity for analytes of different polarity and exhibits nice peak shapes, especially for aldehydes, alcohols and anilines that are prone to severe peak tailing in GC analysis. Interestingly, THCP stationary phase possesses superior resolving ability for aniline and benzenediol positional isomers while OMCP shows preferential selectivity for nonpolar analytes such as hexane isomers. Moreover, calix[4]pyrrole columns also have good thermal stability up to 260°C and repeatability with a relative standard deviation (RSD%) of less than 0.10% for run-to-run and less than 5.2% for column-to-column. This work demonstrates the unique separation performance of calix[4]pyrroles and their promising future as a new class of GC stationary phases. PMID:25173993

  10. Facile synthesis, structural elucidation and spectral analysis of pyrrole 4-imidazole derivatives

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam; Baboo, Vikas

    2015-12-01

    In this work pyrrole 4-imidazole derivatives (3A-3D): benzimidazoles and pyrrole 4-imidazoline have been synthesized by condensation, cyclization and oxidation of ethyl 4-formyl-3,5-dimethyl-1H-pyrrole carboxylate and phenylene diamine derivatives/ethylene diamine. The structure of these biheterocyclic compounds have been derived by elemental and spectroscopic - IR, UV, MS, 1H and 13C NMR analysis as well as theoretical study. The static first hyperpolarizability, β0 values for pyrrole 4-imidazole derivatives, (3A-3D) have been calculated as 10.901 × 10-31, 19.607 × 10-31, 40.323 × 10-31, 5.686 × 10-31 esu, respectively. The gradual increase in β0 value of synthesized pyrrole-benzimidazole derivatives from 3A to 3C is due to addition of acceptors -Cl atom in 3B to -NO2 group in 3C on benzimidazole side. The experimental absorption spectra found to be in UV region and the high β0 values show that the synthesized pyrrole-imidazoles are suitable as non-linear optical (NLO) materials.

  11. Hydrogen transfer in excited pyrrole-ammonia clusters

    NASA Astrophysics Data System (ADS)

    David, O.; Dedonder-Lardeux, C.; Jouvet, C.; Kang, H.; Martrenchard, S.; Ebata, T.; Sobolewski, A. L.

    2004-06-01

    The excited state hydrogen atom transfer reaction (ESHT) has been studied in pyrrole-ammonia clusters [PyH-(NH3)n+hν→Py•+•NH4(NH3)n-1]. The reaction is clearly evidenced through two-color R2P1 experiments using delayed ionization and presents a threshold around 235 nm (5.3 eV). The cluster dynamics has also been explored by picosecond time scale experiments. The clusters decay in the 10-30 ps range with lifetimes increasing with the cluster size. The appearance times for the reaction products are similar to the decay times of the parent clusters. Evaporation processes are also observed in competition with the reaction, and the cluster lifetime after evaporation is estimated to be around 10 ns. The kinetic energy of the reaction products is fairly large and the energy distribution seems quasi mono kinetic. These experimental results rule out the hypothesis that the reaction proceeds through a direct N-H bond rupture but rather imply the existence of a fairly long-lived intermediate state. Calculations performed at the CASSCF/CASMP2 level confirm the experimental observations, and provide some hints regarding the reaction mechanism.

  12. Biocompatible Silk-Poly(Pyrrole) Composite Trilayer Electromechanical Actuators

    NASA Astrophysics Data System (ADS)

    Klemke, Carly; Bradshaw, Nathan; Larson, Jesse; Severt, Sean; Ostrovsky-Snider, Nicholas; Murphy, Amanda; Leger, Janelle

    2015-03-01

    Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymers (CPs) have some desirable traits for use as an actuator, such as the ability to operate in biologically relevant fluids and responsiveness to low voltages. However CPs alone are limited due to their brittle nature and poor solubility. Recently we have shown that a composite material of silk and the CP poly(pyrrole) (PPy) shows promising characteristics as an actuator; it is mechanically robust as well as fully biocompatible. Initial proof-of-concept experiments demonstrated that these composites bend under an applied voltage (or current) using a simple bilayer device. Here we present the development of a trilayer device, composed of two conductive layers separated by an insulating silk layer. This configuration has twice the active surface area as a bilayer, potentially increasing the amount of mechanical motion per volt applied. We will discuss the fabrication and characterization of these devices, as well as their performance and future applications of this technology.

  13. Biocompatible Silk-Poly(Pyrrole) Composite Trilayer Actuators

    NASA Astrophysics Data System (ADS)

    Fengel, Carly; Bradshaw, Nathan; Severt, Sean; Murphy, Amanda; Leger, Janelle

    Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymers (CPs) have some desirable traits for use as an actuator, such as the ability to operate in biologically relevant fluids and responsiveness to low voltages. However CPs alone are limited due to their brittle nature and poor solubility. Recently we have shown that a composite material of silk and the CP poly(pyrrole) (PPy) shows promising characteristics as an actuator; it is mechanically robust as well as fully biocompatible. Initial proof-of-concept experiments demonstrated that these composites bend under an applied voltage (or current) using a simple bilayer device. Here we present trilayer devices composed of two silk-PPy composite layers separated by an insulating silk layer. This configuration results in more charge is passed in comparison to the analogous bilayer system, as well as a more sustainable current response through cycling, resulting in a larger angle of deflection per volt applied. In addition, the motion of the trilayer devices is more symmetric than that of the bilayer analogs, resulting in a more repeatable movement. We will discuss the fabrication and characterization of these devices, as well as their performance and future applications of this technology.

  14. Enzymatically cross-linked injectable alginate-g-pyrrole hydrogels for neovascularization.

    PubMed

    Devolder, Ross; Antoniadou, Eleni; Kong, Hyunjoon

    2013-11-28

    Microparticles capable of releasing protein drugs are often incorporated into injectable hydrogels to minimize their displacement at an implantation site, reduce initial drug burst, and further control drug release rates over a broader range. However, there is still a need to develop methods for releasing drug molecules over extended periods of time, in order to sustain the bioactivity of drug molecules at an implantation site. In this study, we hypothesized that a hydrogel formed through the cross-linking of pyrrole units linked to a hydrophilic polymer would release protein drugs in a more sustained manner, because of an enhanced association between cross-linked pyrrole groups and the drug molecules. To examine this hypothesis, we prepared hydrogels of alginate substituted with pyrrole groups, alginate-g-pyrrole, through a horse-radish peroxidase (HRP)-activated cross-linking of the pyrrole groups. The hydrogels were encapsulated with poly(lactic-co-glycolic acid) (PLGA) microparticles loaded with vascular endothelial growth factor (VEGF). The resulting hydrogel system released VEGF in a more sustained manner than Ca(2+) alginate or Ca(2+) alginate-g-pyrrole gel systems. Finally, implantations of the VEGF-releasing HRP-activated alginate-g-pyrrole hydrogel system on chicken chorioallantoic membranes resulted in the formation of blood vessels in higher densities and with larger diameters, compared to other control conditions. Overall, the drug releasing system developed in this study will be broadly useful for regulating release rates of a wide array of protein drugs, and further enhance the quality of protein drug-based therapies. PMID:23886705

  15. Organic-inorganic interactions in the system of pyrrole-hematite-water at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Ding, Kangle

    2015-11-01

    The distribution and abundance of pyrrolic compounds in sediments and crude oils are most likely influenced by inorganic sedimentary components. In this paper, thermal simulation experiments on the system pyrrole-hematite-water were carried out at elevated temperatures and pressures in order to investigate the effect of organic-inorganic interactions on the preservation of pyrrolic compounds. Compositions of the reaction products were analyzed with GC-MS and GC-FID methods. In the closed system pyrrole-hematite-water, the nitrogen-oxygen exchange obviously occurred at temperatures above 350ºC in accordance with the thermochemical calculation. Large amounts of furan and ammonia were generated after simulation experiments, indicating that the conversion of pyrrole into furan was the dominant reaction. Thermochemical exchange effect between organic nitrogen and inorganic oxygen was obviously facilitated by elevated temperatures and found to be catalyzed by hematite, but inhibited by the increasing volume of water. Thermodynamically water spontaneously reacts with pyrrole above 300ºC. The reaction of pyrrole-hematite-water is an exothermic process in which the reaction heat positively correlates with temperature. The heat released was estimated as 9.0 KJ/(mol) pyrrole - 15.0 KJ/(mol) pyrrole in typical oil reservoirs (100ºC-150ºC) and 15.0-23.0 KJ/(mol) pyrrole in typical gas reservoirs (150ºC-200ºC). The calculated activation energy of the nitrogen-oxygen atom exchange is about 129.59 kJ/mol. According to the experimental results, a small amount of water may effectively initiate the nitrogen-oxygen exchange. The study would improve our evaluating of the preservation and fate of pyrrolic compounds in deeply buried geologic settings and further understanding of thermochemical processes behind the degradation of petroleum.

  16. Structural Studies of Pyrrole-Benzene Complexes by Chirped-Pulse Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lobsiger, Simon; Perez, Cristobal; Zaleski, Daniel P.; Seifert, Nathan A.; Pate, Brooks H.; Pfaffen, Chantal; Trachsel, Maria A.; Leutwyler, Samuel

    2013-06-01

    Non-covalent intermolecular interactions are important in structural biology. The N-H \\cdots π hydrogen bond between amino acid side chains is an important structural determinant and highly affects the secondary structure of proteins. The pyrrole-benzene complex can be viewed as a model system for studying these fundamental interactions. Previous IR and UV spectroscopic studies of the pyrrole-benzene complex by Dauster et al. support a T-shaped structure with an N-H \\cdots π hydrogen bond to the benzene ring. In order to obtain accurate structural information we have investigated the broadband rotational spectrum of the supersonic-jet cooled complexes of pyrrole with benzene and benzene-d_{1} in the 2-18 GHz frequency range. In addition to the hetero dimer we have also observed the two cyclic mixed trimers (pyrrole)_{2}-benzene and pyrrole-(benzene)_{2}. I. Dauster, C. A. Rice, P. Zielke, and M. A. Suhm Phys. Chem. Chem. Phys. {10}, 2827 (2008) C. Pfaffen, D. Infanger, P. Ottiger, H. M. Frey, and S. Leutwyler Phys. Chem. Chem. Phys. {13}, 14110 (2011)

  17. Electrophilic surface sites as precondition for the chemisorption of pyrrole on GaAs(001) surfaces

    SciTech Connect

    Bruhn, Thomas; Fimland, Bjørn-Ove; Vogt, Patrick

    2015-03-14

    We report how the presence of electrophilic surface sites influences the adsorption mechanism of pyrrole on GaAs(001) surfaces. For this purpose, we have investigated the adsorption behavior of pyrrole on different GaAs(001) reconstructions with different stoichiometries and thus different surface chemistries. The interfaces were characterized by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and by reflectance anisotropy spectroscopy in a spectral range between 1.5 and 5 eV. On the As-rich c(4 × 4) reconstruction that exhibits only nucleophilic surface sites, pyrrole was found to physisorb on the surface without any significant modification of the structural and electronic properties of the surface. On the Ga-rich GaAs(001)-(4 × 2)/(6 × 6) reconstructions which exhibit nucleophilic as well as electrophilic surface sites, pyrrole was found to form stable covalent bonds mainly to the electrophilic (charge deficient) Ga atoms of the surface. These results clearly demonstrate that the existence of electrophilic surface sites is a crucial precondition for the chemisorption of pyrrole on GaAs(001) surfaces.

  18. Tandem Copper-Catalyzed Propargylation/Alkyne Azacyclization/Isomerization Reaction under Microwave Irradiation: Synthesis of Fully Substituted Pyrroles.

    PubMed

    Zhang, Xiao-Yan; Yang, Zhi-Wei; Chen, Zhongzhu; Wang, Jun; Yang, Dong-Lin; Shen, Ze; Hu, Li-Li; Xie, Jian-Wu; Zhang, Jin; Cui, Hai-Lei

    2016-03-01

    A copper-catalyzed and microwave-assisted synthesis of fully substituted pyrroles has been developed. A series of pentasubstituted pyrroles, especially α-arylpyrroles, could be obtained in moderate to good yields (up to 93%) through a tandem propargylation/alkyne azacyclization/isomerization sequence from readily available β-enamino compounds and propargyl acetates. PMID:26872395

  19. Isolation and identification of a pyrrolic glutathione conjugate metabolite of the pyrrolizidine alkaloid monocrotaline.

    PubMed

    Lamé, M W; Morin, D; Jones, A D; Segall, H J; Wilson, D W

    1990-05-01

    This report describes the isolation and identification of a monocrotaline-derived, glutathione-conjugated pyrrole obtained from the bile of male Sprague-Dawley rats. Bile obtained from rats given an intravenous bolus of 14C-monocrotaline was fractionated using a series of chromatographic separations. Initial purification with cholestyramine resin removed bile acid and pigment contaminants. Subsequent anion exchange and reversed-phase HPLC separations yielded several fractions that contained the 14C label and tested positive for pyrroles using Ehrlich's reagent. These fractions were analyzed using fast-atom-bombardment tandem mass spectrometry (FAB MS/MS). In addition to glutathione-conjugated dehydroretronecine, at least one other pyrrole present had similar ionic properties. The latter was not present in amounts sufficient for positive identification. PMID:2111054

  20. Electrooxidation of pyrrole-terminated self-assembled lipoic acid derivatives

    NASA Astrophysics Data System (ADS)

    Cabrita, Joana F.; Viana, Ana S.; Eberle, Christoph; Montforts, Franz-Peter; Mourato, Ana; Abrantes, Luisa M.

    2009-08-01

    New pyrrole derivatives, pyrrolyl lipoic acid (Py-LA 3) and dipyrrolyl lipoic acid (Py 2-LA 2) have been used for surface attachment and immobilisation on gold surfaces, by self-assembly. The electrooxidation of the surface-confined pyrroles was analysed by cyclic voltammetry and the modified electrodes morphological and thickness changes addressed by scanning probe microscopy and ellipsometry. The data support the formation of oligomers as a result of the pendant-pyrrolyl units ease oxidation but provide no evidence of an effective subsequent polymerisation.

  1. Template Synthesis of Decaphyrin without Meso-Bridges: Cyclo[10]pyrrole.

    PubMed

    Okujima, Tetsuo; Ando, Chie; Agrawal, Saurabh; Matsumoto, Hiroki; Mori, Shigeki; Ohara, Keishi; Hisaki, Ichiro; Nakae, Takahiro; Takase, Masayoshi; Uno, Hidemitsu; Kobayashi, Nagao

    2016-06-22

    An acenaphthylene-fused cyclo[10]pyrrole 1b was selectively synthesized via an oxidative coupling reaction of the corresponding 2,2'-bipyrrole with the appropriate dianion template, croconate anion. The structure of 1b as the isolated largest cyclo[n]pyrrole was elucidated by X-ray crystallographic analysis. The absorption spectrum exhibited a markedly red-shifted, intensified L band at 1982 nm, which was interpreted by application of Michl's perimeter and Gouterman's 4-orbital models, supported by magnetic circular dichroism (MCD) data and theoretical calculations. PMID:27268663

  2. Lactic acid as an invaluable green solvent for ultrasound-assisted scalable synthesis of pyrrole derivatives.

    PubMed

    Wang, Shi-Fan; Guo, Chao-Lun; Cui, Ke-ke; Zhu, Yan-Ting; Ding, Jun-Xiong; Zou, Xin-Yue; Li, Yi-Hang

    2015-09-01

    Lactic acid has been used as a bio-based green solvent to study the ultrasound-assisted scale-up synthesis. We report here, for the first time, on the novel and scalable process for synthesis of pyrrole derivatives in lactic acid solvent under ultrasonic radiation. Eighteen pyrrole derivatives have been synthesized in lactic acid solvent under ultrasonic radiation and characterized by (1)H NMR, IR, ESI MS. The results show, under ultrasonic radiation, lactic acid solvent can overcome the scale-up challenges and exhibited many advantages, such as bio-based origin, shorter reaction time, lower volatility, higher yields, and ease of isolating the products. PMID:25605585

  3. Label-free impedimetric biosensor for Salmonella Typhimurium detection based on poly [pyrrole-co-3-carboxyl-pyrrole] copolymer supported aptamer.

    PubMed

    Sheikhzadeh, E; Chamsaz, M; Turner, A P F; Jager, E W H; Beni, V

    2016-06-15

    The Gram-negative bacterium, Salmonella Typhimurium (S. Typhimurium) is a food borne pathogen responsible for numerous hospitalisations and deaths all over the world. Conventional detection methods for pathogens are time consuming and labour-intensive. Hence, there is considerable interest in faster and simpler detection methods. Polypyrrole-based polymers, due to their intrinsic chemical and electrical properties, have been demonstrated to be valuable candidates for the fabrication of chemo/biosensors and functional surfaces. Similarly aptamers have been shown to be good alternatives to antibodies in the development of affinity biosensors. In this study, we report on the combination of poly [pyrrole-co-3-carboxyl-pyrrole] copolymer and aptamer for the development of a label-less electrochemical biosensor suitable for the detection of S. Typhimurium. Impedimetric measurements were facilitated by the effect of the aptamer/target interaction on the intrinsic conjugation of the poly [pyrrole-co-3-carboxyl-pyrrole] copolymer and subsequently on its electrical properties. The aptasensor detected S. Typhimurium in the concentration range 10(2)-10(8) CFU mL(-1) with high selectivity over other model pathogens and with a limit of quantification (LOQ) of 100 CFU mL(-1) and a limit of detection (LOD) of 3 CFU mL(-1). The suitability of the aptasensor for real sample detection was demonstrated via recovery studies performed in spiked apple juice samples. We envisage this to be a viable approach for the inexpensive and rapid detection of pathogens in food, and possibly in other environmental samples. PMID:26836649

  4. Cognition and order in Langmuir-Blodgett films of a 3-hexadecyl pyrrole and ferrocene-derivatized pyrrole mixed monolayer system

    NASA Astrophysics Data System (ADS)

    Samuelson, L.; Rahman, A. K. M.; Puglia, G. P.; Clough, S.; Tripathy, S.; Inagaki, T.; Yang, X. Q.; Skotheim, T. A.; Okamoto, Y.

    Novel, self-assembled materials were designed and produced from first principle to possess unique structural hierarchy and electronic and optical properties. The Langmuir-Blodgett technique was used to study the molecular organization of a mixed 3-hexadecyl pyrrole (3HDP) and ferrocene-derivatized pyrrole (Fc-Py) surfactant system. The pyrrole moiety was chosen for its' well established electronic and optical properties when polymerized, while ferrocene, it is theorized, if properly oriented into a Langmuir-Blodgett monolayer film may show a layered array of transition metals which would be extremely valuable as a model for 2-D magnets. The ferrocene group may also provide the possibility of charge coupling between neutral ferrocene and oxidized ferricenium which could be controlled electrochemically or photochemically. It has been determined that stable monolayer films of the mixed system could be formed at the air-water interface. The growth and assembly process led to polypyrrole 2-D lattices with heretofore unsurpassed order. In fact, the process of template polymerization leads to a new crystal phase for the polypyrrole component of the thin film structure. Various monolayer and multilayer films were prepared on platinum coated substrates for surface spectroscopic characterization using synchrotron radiation. Near Edge X-Ray Absorption Fine Structure studies revealed that highly ordered multilayer structures are being formed.

  5. Cognition and order in Langmuir-Blodgett films of a 3-hexadecyl pyrrole and ferrocene-derivatized pyrrole mixed monolayer system

    SciTech Connect

    Samuelson, L.; Rahman, A.K.M.; Puglia, G.P.; Clough, S.; Tripathy, S.; Inagaki, T.; Yang, X.Q.; Skotheim, T.A.; Okamoto, Y.

    1989-01-01

    Novel, self-assembled materials have been designed and produced from first principle to possess unique structural hierarchy and electronic and optical properties. The Langmuir-Blodgett technique was used to study the molecular organization of a mixed 3-hexadecyl pyrrole (3HDP) and ferrocene-derivatized pyrrole (Fc-Py) surfactant system. The pyrrole moiety was chosen for its' well established electronic and optical properties when polymerized, while ferrocene, it is theorized, if properly oriented into a Langmuir-Blodgett monolayer film may show a layered array of transition metals which would be extremely valuable as a model for two-dimensional magnets. The ferrocene group may also provide the possibility of charge coupling between neutral ferrocene and oxidized ferricenium which could be controlled electrochemically or photochemically. It has been determined that stable monolayer films of the mixed system could be formed at the air-water interface. The growth and assembly process led to polypyrrole 2-D lattices with heretofore unsurpassed order. In fact, the process of template polymerization leads to a new crystal phase for the polypyrrole component of the thin film structure. Various monolayer and multilayer films were prepared on platinum coated substrates for surface spectroscopic characterization using synchrotron radiation. Near Edge X-Ray Absorption Fine Structure studies revealed that highly ordered multilayer structures are being formed. 8 refs., 4 figs., 1 tab.

  6. Synthesis and Evaluation of Novel Pyrroles and Pyrrolopyrimidines as Anti-Hyperglycemic Agents

    PubMed Central

    Mohamed, M. S.; Ali, S. A.; Abdelaziz, D. H. A.; Fathallah, Samar S.

    2014-01-01

    A series of pyrrole and pyrrolopyrimidine derivatives were examined for their in vivo antihyperglycemic activity. Compounds Ia–c,e, and IVg showed promising antihyperglycemic activity equivalent to a well-known standard antihyperglycemic drug, Glimepiride (Amaryl, 4 mg/kg). In this paper, we examine and discuss the structure-activity relationships and antihyperglycemic activity of these compounds. PMID:25054134

  7. Identification of a new electron-transfer relaxation pathway in photoexcited pyrrole dimers

    NASA Astrophysics Data System (ADS)

    Neville, Simon P.; Kirkby, Oliver M.; Kaltsoyannis, Nikolas; Worth, Graham A.; Fielding, Helen H.

    2016-04-01

    Photoinduced electron transfer is central to many biological processes and technological applications, such as the harvesting of solar energy and molecular electronics. The electron donor and acceptor units involved in electron transfer are often held in place by covalent bonds, π-π interactions or hydrogen bonds. Here, using time-resolved photoelectron spectroscopy and ab initio calculations, we reveal the existence of a new, low-energy, photoinduced electron-transfer mechanism in molecules held together by an NH⋯π bond. Specifically, we capture the electron-transfer process in a pyrrole dimer, from the excited π-system of the donor pyrrole to a Rydberg orbital localized on the N-atom of the acceptor pyrrole, mediated by an N-H stretch on the acceptor molecule. The resulting charge-transfer state is surprisingly long lived and leads to efficient electronic relaxation. We propose that this relaxation pathway plays an important role in biological and technological systems containing the pyrrole building block.

  8. Identification of a new electron-transfer relaxation pathway in photoexcited pyrrole dimers.

    PubMed

    Neville, Simon P; Kirkby, Oliver M; Kaltsoyannis, Nikolas; Worth, Graham A; Fielding, Helen H

    2016-01-01

    Photoinduced electron transfer is central to many biological processes and technological applications, such as the harvesting of solar energy and molecular electronics. The electron donor and acceptor units involved in electron transfer are often held in place by covalent bonds, π-π interactions or hydrogen bonds. Here, using time-resolved photoelectron spectroscopy and ab initio calculations, we reveal the existence of a new, low-energy, photoinduced electron-transfer mechanism in molecules held together by an NH⋯π bond. Specifically, we capture the electron-transfer process in a pyrrole dimer, from the excited π-system of the donor pyrrole to a Rydberg orbital localized on the N-atom of the acceptor pyrrole, mediated by an N-H stretch on the acceptor molecule. The resulting charge-transfer state is surprisingly long lived and leads to efficient electronic relaxation. We propose that this relaxation pathway plays an important role in biological and technological systems containing the pyrrole building block. PMID:27098394

  9. Synthesis of Dihydropyrrolizine and Tetrahydroindolizine Scaffolds from Pyrroles by Titanocene(III) Catalysis.

    PubMed

    Hildebrandt, Sven; Gansäuer, Andreas

    2016-08-01

    A synthetic approach to dihydropyrrolizine and tetrahydroindolizine scaffolds from pyrroles has been developed. The key step, a titanocene(III)-catalyzed radical arylation that proceeds by C-H functionalization is atom-economical and tolerates a large variety of functional groups. The reaction is therefore attractive for the swift assembly of functional and structural diversity. PMID:27383638

  10. Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction

    SciTech Connect

    Wintergerst, Mr. Matthieu; Levitskaia, Tatiana G.; Moyer, Bruce A; Sessler, Jonathan L.; Delmau, Laetitia Helene

    2008-01-01

    Solvent-extraction studies provide confirming evidence that meso-octamethylcalix[4]pyrrole acts as an ion-pair receptor for cesium chloride and cesium bromide in nitrobenzene solution. The stoichiometry of the interaction under extraction conditions from water to nitrobenzene was determined from plots of the cesium distribution ratios vs cesium salt and receptor concentration, indicating the formation of an ionpaired 1:1:1 cesium:calix[4]pyrrole:halide complex. The extraction results were modeled to evaluate the equilibria inherent to the solvent-extraction system, with either chloride or bromide. The binding energy between the halide anion and the calix[4]pyrrole was found to be about 7 kJ/mol larger for cesium chloride than for the cesium bromide. The ion-pairing free energies between the calix[4]pyrrole-halide complex and the cesium cation are nearly the same within experimental uncertainty for either halide, consistent with a structural model in which the Cs+ cation resides in the calix bowl. These results are unexpected since nitrobenzene is a polar solvent that generally leads to dissociated complexes in the organic phase when used as a diluent in extraction studies of univalent ions. Control studies involving nitrate revealed no evidence of ion pairing for CsNO3 under conditions identical to those where it is observed for CsCl and CsBr.

  11. Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction

    SciTech Connect

    Wintergerst, Mr. Matthieu; Levitskaia, Tatiana G.; Moyer, Bruce A; Sessler, Jonathan L.; Delmau, Laetitia Helene

    2008-01-01

    Solvent extraction studies provide confirming evidence that meso-octamethylcalix[4]pyrrole acts as an ion-pair receptor for cesium chloride and cesium bromide in nitrobenzene solution. The stoichiometry of the interaction under extraction conditions from water to nitrobenzene was determined from plots of the cesium distribution ratios vs. cesium salt and receptor concentration, indicating the formation of an ion-paired 1:1:1 cesium:calix[4]pyrrole:halide complex. The extraction results were modeled to evaluate the equilibria inherent to the solvent extraction system, either with chloride or bromide. The binding energy between the halide anion and the calix[4]pyrrole was found to be about 7 kJ/mol larger for cesium chloride than for the cesium bromide. The ion-pairing free energies between the calix[4]pyrrole-halide complex and the cesium cation are nearly the same within experimental uncertainty for either halide, consistent with a structural model in which the Cs+ cation resides in the calix bowl. These results are unexpected since nitrobenzene is a very polar solvent that generally leads to dissociated complexes in the organic phase when used as a diluent in extraction studies of univalent ions. Control studies involving nitrate revealed no evidence of ion-pairing for CsNO3 under conditions identical to those where it is observed for CsCl and CsBr.

  12. Three-component synthesis of polysubstituted pyrroles from α-diazoketones, nitroalkenes, and amines.

    PubMed

    Hong, Deng; Zhu, Yuanxun; Li, Yao; Lin, Xufeng; Lu, Ping; Wang, Yanguang

    2011-09-01

    Polysubstituted pyrroles are regiospecifically synthesized via the copper-catalyzed three-component reaction of α-diazoketones, nitroalkenes, and amines under aerobic conditions. The cascade process involves an N-H insertion of carbene, a copper-catalyzed oxidative dehydrogenation of amine, and a [3 + 2] cycloaddition of azomethine ylide. PMID:21830767

  13. Identification of a new electron-transfer relaxation pathway in photoexcited pyrrole dimers

    PubMed Central

    Neville, Simon P.; Kirkby, Oliver M.; Kaltsoyannis, Nikolas; Worth, Graham A.; Fielding, Helen H.

    2016-01-01

    Photoinduced electron transfer is central to many biological processes and technological applications, such as the harvesting of solar energy and molecular electronics. The electron donor and acceptor units involved in electron transfer are often held in place by covalent bonds, π–π interactions or hydrogen bonds. Here, using time-resolved photoelectron spectroscopy and ab initio calculations, we reveal the existence of a new, low-energy, photoinduced electron-transfer mechanism in molecules held together by an NH⋯π bond. Specifically, we capture the electron-transfer process in a pyrrole dimer, from the excited π-system of the donor pyrrole to a Rydberg orbital localized on the N-atom of the acceptor pyrrole, mediated by an N–H stretch on the acceptor molecule. The resulting charge-transfer state is surprisingly long lived and leads to efficient electronic relaxation. We propose that this relaxation pathway plays an important role in biological and technological systems containing the pyrrole building block. PMID:27098394

  14. Super Aryl-Extended Calix[4]pyrroles: Synthesis, Binding Studies, and Attempts To Gain Water Solubility.

    PubMed

    Escobar, Luis; Aragay, Gemma; Ballester, Pablo

    2016-09-12

    We describe the synthesis of unprecedented calix[4]pyrrole receptors featuring "super aryl extended" (SAE) cavities. We elaborated the aromatic cavity provided by the αααα-isomer of para-tetraiodo-meso-phenyl calix[4]pyrrole by installing ethynyl-aryl substituents at its upper rim. We report the binding properties of the prepared SAE-calix[4]pyrrole tetraester towards pyridyl-N-oxides. The binding data revealed the formation of thermodynamically and kinetically highly stable 1:1 complexes. The complexation-induced chemical shifts indicated the formation of hydrogen bonds and aromatic interactions with the calix-core adopting the cone conformation. We quantified the additional interactions established between the four terminal aryl groups and the para-phenyl substituent of 4-phenyl pyridine N-oxide to be in the order of 1 kcal mol(-1) . The complex formation rate was found to be close to the diffusion control suggesting that the free host adopted a 1,3-alternate conformation. Finally, we attempted to gain water solubility of SAE-calix[4]pyrroles using derivatives that display four ionizable or charged groups at their upper rims. PMID:27505617

  15. Comments on the Treatment of Aromaticity and Acid-Base Character of Pyridine and Pyrrole in Contemporary Organic Chemistry Textbooks

    NASA Astrophysics Data System (ADS)

    Anderson, Hugh J.; Bauer, Ludwig

    1999-08-01

    Presentations of aromaticity and acid-base character of pyridine and pyrrole in 18 contemporary organic chemistry textbooks were surveyed. Superficially, each of these two monoaza aromatic heterocycles retains an electron pair on its sp2-hybridized ring nitrogen, ostensibly available for neutralization with a proton to form a salt. The two nonbonded electrons in pyridine, in an sp2-hybridized orbital outside the ring, are not interacting with the 6p-electron aromatic sextet and thus are fully available for neutralization to form an N+-H pyridinium cation. However, in pyrrole, the nonbonded electron pair on nitrogen is part of the aromatic 6p- electron sextet and is not available for NH salt formation, since this would generate an aliphatic (highly reactive) diene imminium cation, which would destroy pyrrole's aromaticity. However, electrophilic attack of a proton in an irreversible manner attacks C-2 of pyrrole to form a resonance-stabilized cationic intermediate capable of further transformations. Pyridine is classified correctly as a weak base, while pyrrole in aqueous solutions is classified essentially neutral. In reality, pyrrole is a weak acid, neutralized by strong bases to generate a stable aromatic and highly reactive nucleophilic anion. Most authors fail to stress the acidic property of pyrrole and some organic texts need revision to eliminate some misconceptions and omissions.

  16. Ground state structures and excited state dynamics of pyrrole-water complexes: Ab initio excited state molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Kumar, Anupriya; Kołaski, Maciej; Kim, Kwang S.

    2008-01-01

    Structures of the ground state pyrrole-(H2O)n clusters are investigated using ab initio calculations. The charge-transfer driven femtosecond scale dynamics are studied with excited state ab initio molecular dynamics simulations employing the complete-active-space self-consistent-field method for pyrrole-(H2O)n clusters. Upon the excitation of these clusters, the charge density is located over the farthest water molecule which is repelled by the depleted π-electron cloud of pyrrole ring, resulting in a highly polarized complex. For pyrrole-(H2O), the charge transfer is maximized (up to 0.34a.u.) around ˜100fs and then oscillates. For pyrrole-(H2O)2, the initial charge transfer occurs through the space between the pyrrole and the π H-bonded water molecule and then the charge transfer takes place from this water molecule to the σ H-bonded water molecule. The total charge transfer from the pyrrole to the water molecules is maximized (up to 0.53a.u.) around ˜100fs.

  17. Direct Arylation of Pyrroles via Indirect Electroreductive C-H Functionalization Using Perylene Bisimide as an Electron-Transfer Mediator.

    PubMed

    Sun, Guoquan; Ren, Shuya; Zhu, Xinhai; Huang, Manna; Wan, Yiqian

    2016-02-01

    The indirect electroreductive coupling of aryl halides and pyrroles was successfully conducted using a catalytic amount of perylene bisimide as a mediator in 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([EMIM]NTf2)/DMSO. PMID:26800089

  18. Hydrogen-bonded structures of pyrrole-solvent clusters: Infrared cavity ringdown spectroscopy and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Matsumoto, Yoshiteru; Honma, Kenji

    2009-02-01

    The hydrogen-bonded structures of pyrrole-solvent (H2O,CH3OH,C2H5OH) binary clusters were studied by the combination of experimental and theoretical techniques. Infrared cavity ringdown spectroscopy was applied to observe the NH and OH stretching vibrations of the clusters. The structures, binding energies, and normal modes of the binary clusters were obtained by quantum chemical calculations of the MP2/6-31+G(d,p) and B3LYP/6-311+G(d,p) levels. For the 1:1 clusters of pyrrole-H2O, pyrrole-CH3OH, and pyrrole-C2H5OH, the hydrogen-bonded NH stretching vibrations were observed at 3448, 3414, and 3408 cm-1, respectively. They were redshifted from the NH stretching vibration of the pyrrole monomer, and the amounts of the redshift were proportional to the proton affinities of the solvent molecules. MP2 level calculations revealed that the σ-type (NH⋯O) hydrogen-bonded structures had 7.6-9.0 kJ/mol larger binding energies than the π-type structures (OH⋯π electron cloud of pyrrole), and that the vibrational frequencies of the σ-type structures are consistent with the observed spectra. In addition to the 1:1 clusters, the NH or OH stretching vibrations of pyrrole-CH3OH binary clusters were observed at 3432 and 3549 cm-1. Among three optimized structures of the pyrrole-(CH3OH)2, the σ-π bridge pyrrole-(CH3OH)2 provided a reasonable agreement between the observed and calculated vibrational frequencies. For the pyrrole-H2O binary clusters, three new bands were observed at 3414, 3435, and 3541 cm-1. These bands are consistent with the calculated NH and OH stretching vibrations of the (pyrrole)2-H2O cluster, which has a closed cyclic hydrogen-bonded structure.

  19. Graphene/Poly(aniline-co-pyrrole) Nanocomposite: Potential Candidate for Supercapacitor and Microwave Absorbing Applications.

    PubMed

    Sahoo, Sumanta; Bhattacharya, Pallab; Dhibar, Saptarshi; Hatui, Goutam; Das, Tanya; Das, Chapal Kumar

    2015-09-01

    A simple and cost-effective in-situ chemical route to prepare the nanocomposites based on graphene and Poly(aniline-co-pyrrole) [PPP] has been proposed. Introduction of graphene changes the morphology of copolymer from spherical to fiber like. Graphene/Poly(aniline-co-pyrrole) [GPPP] nanocomposite achieved highest specific capacitance of 351 F/g and energy density of 124.8 Wh/Kg at 10 mV/s scan rate. The composite also obtained moderate specific capacitance retention of 66% after 500 cycles, which establish its potentiality as supercapacitor electrode materials. The composite also exhibited high electrical conductivity and superior microwave absorbing properties (maximum reflection loss is -29.97 dB). The absorption range corresponding to ≥ 90% absorption (or -10 dB) is 2.72 GHz which is excellent for the microwave absorbing applications. PMID:26716265

  20. Ab initio multiple cloning simulations of pyrrole photodissociation: TKER spectra and velocity map imaging

    DOE PAGESBeta

    Makhov, Dmitry V.; Saita, Kenichiro; Martinez, Todd J.; Shalashilin, Dmitrii V.

    2014-12-11

    In this study, we report a detailed computational simulation of the photodissociation of pyrrole using the ab initio Multiple Cloning (AIMC) method implemented within MOLPRO. The efficiency of the AIMC implementation, employing train basis sets, linear approximation for matrix elements, and Ehrenfest configuration cloning, allows us to accumulate significant statistics. We calculate and analyze the total kinetic energy release (TKER) spectrum and Velocity Map Imaging (VMI) of pyrrole and compare the results directly with experimental measurements. Both the TKER spectrum and the structure of the velocity map image (VMI) are well reproduced. Previously, it has been assumed that the isotropicmore » component of the VMI arises from long time statistical dissociation. Instead, our simulations suggest that ultrafast dynamics contributes significantly to both low and high energy portions of the TKER spectrum.« less

  1. Direct Synthesis of Highly Substituted Pyrroles and Dihydropyrroles Using Linear Selective Hydroacylation Reactions.

    PubMed

    Majhail, Manjeet K; Ylioja, Paul M; Willis, Michael C

    2016-06-01

    Rhodium(I) catalysts incorporating small bite-angle diphosphine ligands, such as (Cy2 P)2 NMe or bis(diphenylphosphino)methane (dppm), are effective at catalysing the union of aldehydes and propargylic amines to deliver the linear hydroacylation adducts in good yields and with high selectivities. In situ treatment of the hydroacylation adducts with p-TSA triggers a dehydrative cyclisation to provide the corresponding pyrroles. The use of allylic amines, in place of the propargylic substrates, delivers functionalised dihydropyrroles. The hydroacylation reactions can also be combined in a cascade process with a Rh(I) -catalysed Suzuki-type coupling employing aryl boronic acids, providing a three-component assembly of highly substituted pyrroles. PMID:27106284

  2. Acetylcholinesterase-Inhibiting Activity of Pyrrole Derivatives from a Novel Marine Gliding Bacterium, Rapidithrix thailandica

    PubMed Central

    Sangnoi, Yutthapong; Sakulkeo, Oraphan; Yuenyongsawad, Supreeya; Kanjana-opas, Akkharawit; Ingkaninan, Kornkanok; Plubrukarn, Anuchit; Suwanborirux, Khanit

    2008-01-01

    Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 μM). Two related pyrrole derivatives, 3-(2′-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other strains of R. thailandica. The isolation of 3 from a natural source is reported here for the first time. Compound 4 was proposed to be an isolation artifact derived from 3. The two isolated compounds were virtually inactive in the acetylcholinesterase-inhibitory assay (enzyme inhibition < 30% at 0.1 g L−1). PMID:19172195

  3. Langmuir-Blodgett films of a pyrrole and ferrocene mixed surfactant system

    SciTech Connect

    Samuelson, L.; Rahman, A.K.M.; Clough, S.; Tripathy, S.; Hale, P.D.; Inagaki, T.; Skotheim, T.A.; Okamoto, Y. . Dept. of Chemistry; Brookhaven National Lab., Upton, NY; Polytechnic Univ., Brooklyn, NY . Dept. of Chemistry)

    1989-01-01

    The Langmuir-Blodgett technique was used to study the molecular organization of a mixed 3-hexadecyl pyrrole (3HDP) and ferrocene-derivatized pyrrole (Fc-Py) surfactant system. It has been determined that stable monolayer films of the mixed system could be formed at the air-water interface. The growth and assembly process led to polypyrrole 2-D lattices with heretofore unsurpassed order. In fact, the process of template polymerization, it appears, leads to a new crystal phase for the polypyrrole component of the thin film structure. Various monolayer and multilayer films were prepared on platinum coated substrates for surface spectroscopic characterization. Near Edge X-Ray Absorption Fine Structure (NEXAFS) studies revealed that highly ordered multilayer structures are being formed. Electrochemical studies have been initiated to determine the feasibility of these films in molecular electronic device applications. 13 refs., 6 figs., 1 tab.

  4. Toxic Dopamine Metabolite DOPAL Forms an Unexpected Dicatechol Pyrrole Adduct with Lysines of α-Synuclein.

    PubMed

    Werner-Allen, Jon W; DuMond, Jenna F; Levine, Rodney L; Bax, Ad

    2016-06-20

    Parkinson's disease has long been known to involve the loss of dopaminergic neurons in the substantia nigra and the coincidental appearance of Lewy bodies containing oligomerized forms of α-synuclein. The "catecholaldehyde hypothesis" posits a causal link between these two central pathologies mediated by 3,4-dihydroxyphenylacetaldehyde (DOPAL), the most toxic dopamine metabolite. Here we determine the structure of the dominant product in reactions between DOPAL and α-synuclein, a dicatechol pyrrole lysine adduct. This novel modification results from the addition of two DOPAL molecules to the Lys sidechain amine through their aldehyde moieties and the formation of a new carbon-carbon bond between their alkyl chains to generate a pyrrole ring. The product is detectable at low concentrations of DOPAL and its discovery should provide a valuable chemical basis for future studies of DOPAL-induced crosslinking of α-synuclein. PMID:27158766

  5. Design and synthesis of hepatoselective, pyrrole-based HMG-CoA reductase inhibitors.

    PubMed

    Pfefferkorn, Jeffrey A; Song, Yuntao; Sun, Kuai-Lin; Miller, Steven R; Trivedi, Bharat K; Choi, Chulho; Sorenson, Roderick J; Bratton, Larry D; Unangst, Paul C; Larsen, Scott D; Poel, Toni-Jo; Cheng, Xue-Min; Lee, Chitase; Erasga, Noe; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Olsen, Karl; Mertz, Thomas; Sekerke, Catherine; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole; Chen, Huifen; Eberstadt, Matthias

    2007-08-15

    This manuscript describes the design and synthesis of a series of pyrrole-based inhibitors of HMG-CoA reductase for the treatment of hypercholesterolemia. Analogs were optimized using structure-based design and physical property considerations resulting in the identification of 44, a hepatoselective HMG-CoA reductase inhibitor with excellent acute and chronic efficacy in a pre-clinical animal models. PMID:17574412

  6. Pyridazine N-Oxides as Precursors of Metallocarbenes: Rhodium-Catalyzed Transannulation with Pyrroles.

    PubMed

    Kanchupalli, Vinaykumar; Joseph, Desna; Katukojvala, Sreenivas

    2015-12-01

    Pyridazine N-oxides are used for the first time as precursors of metallocarbenes. These nitrogen-rich heterocycles led to the discovery of a novel acceptor and donor-acceptor enalcarbenoids. The synthetic utility of these metallocarbenes was demonstrated in the rhodium-catalyzed denitrogenative transannulation of pyridazine N-oxides with pyrroles to the valuable alkyl, 7-aryl, and 7-styryl indoles. The transannulation strategy was applied to the synthesis of a potent anticancer agent. PMID:26588048

  7. Synthesis of multisubstituted pyrroles from doubly activated cyclopropanes using an iron-mediated oxidation domino reaction.

    PubMed

    Zhang, Zhiguo; Zhang, Wei; Li, Junlong; Liu, Qingfeng; Liu, Tongxin; Zhang, Guisheng

    2014-11-21

    An alternative route has been developed for the construction of multisubstituted pyrrole derivatives from readily available, doubly activated cyclopropanes and anilines using an iron-mediated oxidation domino reaction (i.e., sequential ring-opening, cyclization, and dehydrogenation reactions). This reaction uses readily available reactants and is tolerant of a broad range of substrates, with the desired products being formed in good to excellent yields. PMID:25330125

  8. Inhibition of endotoxin-induced airway epithelial cell injury by a novel family of pyrrol derivates.

    PubMed

    Cabrera-Benítez, Nuria E; Pérez-Roth, Eduardo; Ramos-Nuez, Ángela; Sologuren, Ithaisa; Padrón, José M; Slutsky, Arthur S; Villar, Jesús

    2016-06-01

    Inflammation and apoptosis are crucial mechanisms for the development of the acute respiratory distress syndrome (ARDS). Currently, there is no specific pharmacological therapy for ARDS. We have evaluated the ability of a new family of 1,2,3,5-tetrasubstituted pyrrol compounds for attenuating lipopolysaccharide (LPS)-induced inflammation and apoptosis in an in vitro LPS-induced airway epithelial cell injury model based on the first steps of the development of sepsis-induced ARDS. Human alveolar A549 and human bronchial BEAS-2B cells were exposed to LPS, either alone or in combination with the pyrrol derivatives. Rhein and emodin, two representative compounds with proven activity against the effects of LPS, were used as reference compounds. The pyrrol compound that was termed DTA0118 had the strongest inhibitory activity and was selected as the lead compound to further explore its properties. Exposure to LPS caused an intense inflammatory response and apoptosis in both A549 and BEAS-2B cells. DTA0118 treatment downregulated Toll-like receptor-4 expression and upregulated nuclear factor-κB inhibitor-α expression in cells exposed to LPS. These anti-inflammatory effects were accompanied by a significantly lower secretion of interleukin-6 (IL-6), IL-8, and IL-1β. The observed antiapoptotic effect of DTA0118 was associated with the upregulation of antiapoptotic Bcl-2 and downregulation of proapoptotic Bax and active caspase-3 protein levels. Our findings demonstrate the potent anti-inflammatory and antiapoptotic properties of the pyrrol DTA0118 compound and suggest that it could be considered as a potential drug therapy for the acute phase of sepsis and septic ARDS. Further investigations are needed to examine and validate these mechanisms and effects in a clinically relevant animal model of sepsis and sepsis-induced ARDS. PMID:26999659

  9. An amperometric urea biosensor based on covalent immobilization of urease onto an electrochemically prepared copolymer poly (N-3-aminopropyl pyrrole-co-pyrrole) film.

    PubMed

    Rajesh; Bisht, Vandana; Takashima, Wataru; Kaneto, Keiichi

    2005-06-01

    An amperometric biosensor has been developed for the quantitative determination of urea in aqueous solution. The principle is based on the use of pH-sensitive redox active dissolved hematein molecule. The enzyme, urease (Urs), was covalently immobilized on a conducting copolymer poly (N-3-aminopropyl pyrrole-co-pyrrole) film, electrochemically prepared onto an indium-tin-oxide (ITO)-coated glass plate. The covalent linkage of enzyme and porous morphology of the polymer film lead to high enzyme loading and an increased lifetime stability of the enzyme electrode. Amperometric response was measured as a function of concentration of urea, at fixed bias voltage of 0.0 V vs. Ag/AgCl in a phosphate buffer (pH 7.0). The electrode gives a linear response range of 0.16-5.02 mM for urea in aqueous medium. The response time is 40 s reaching to a 95% steady-state current value, and 80% of the enzyme activity is retained for about 2 months. PMID:15744952

  10. ESI-MS Characterization of a Novel Pyrrole-Inosine Nucleoside that Interacts with Guanine Bases

    PubMed Central

    Pierce, Sarah E.; Sherman, Courtney L.; Jayawickramarajah, Janarthanan; Lawrence, Candace M.; Sessler, Jonathan L.; Brodbelt, Jennifer S.

    2008-01-01

    Based on binding studies undertaken by electrospray ionization-mass spectrometry, a synthetic pyrrole-inosine nucleoside, 1, capable of forming an extended three-point Hoogsteen-type hydrogen-bonding interaction with guanine, is shown to form specific complexes with two different quadruplex DNA structures [dTG4T]4 and d(T2G4)4 as well as guanine rich duplex DNA. The binding interactions of two other analogs were evaluated in order to unravel the structural features that contribute to specific DNA recognition. The importance of the Hoogsteen interactions was confirmed through the absence of specific binding when the pyrrole NH hydrogen-bonding site was blocked or removed. While 2, with a large blocking group, was not found to interact with virtually any form of DNA, 3, with the pyrrole functionality missing, was found to interact non-specifically with several types of DNA. The specific binding of 1 to guanine rich DNA emphasizes the necessity of careful ligand design for specific sequence recognition. PMID:18790136

  11. A General Route to β-Substituted Pyrroles by Transition-Metal Catalysis.

    PubMed

    Bunrit, Anon; Sawadjoon, Supaporn; Tšupova, Svetlana; Sjöberg, Per J R; Samec, Joseph S M

    2016-02-19

    An atom-efficient route to pyrroles substituted in the β-position has been achieved in four high yielding steps by a combination of Pd, Ru, and Fe catalysis with only water and ethene as side-products. The reaction is general and gives pyrroles substituted in the β-position with linear and branched alkyl, benzyl, or aryl groups in overall good yields. The synthetic route includes a Pd-catalyzed monoallylation step of amines with substituted allylic alcohols that proceeds to yield the monoallylated products in moderate to excellent yields. In a second step, unsymmetrical diallylated aromatic amines are generated from the reaction of a second allylic alcohol with high selectivity in moderate to good yields by control of the reaction temperature. Ru-catalyzed ring-closing metathesis performed on the diallylated aromatic amines yields the pyrrolines substituted in the β-position in excellent yields. By addition of ferric chloride to the reaction mixture, a selective aromatization to yield the corresponding pyrroles substituted in the β-position was achieved. A reaction mechanism involving a palladium hydride, generated from insertion of palladium to O-H of an allyl alcohol, that is responsible for the C-O bond cleavage to generate the π-allyl intermediate is proposed. PMID:26789020

  12. Evaluation on the inhibition of pyrrol-2-yl ethanone derivatives to lactate dehydrogenase and anticancer activities

    NASA Astrophysics Data System (ADS)

    Lu, Na-Na; Weng, Zhao-Yue; Chen, Qiu-Yun; Boison, Daniel; Xiao, Xin-Xin; Gao, Jing

    2016-08-01

    Lactate dehydrogenase A (LDH-A) is a potentially important metabolic target for the inhibition of the highly activated glycolysis pathway in cancer cells. In order to develop bifunctional compounds as inhibitor of LDH-A and anticancer agents, two pyrrol-2-yl methanone (or ethanone) derivatives (PM1 and PM2) were synthesized and evaluated as inhibitors of LDH-A based on the enzyme assay and cell assay by spectroscopy analysis. Fluorescence and CD spectra results demonstrated that both the change of second structure of LDH-A and the affinity interaction for compounds to LDH-A gave great effect on the activity of LDH-A. In particular, low concentration of compounds (1 μμ-25 μμ) could change the level of pyruvate in cancer cells. Moreover, the in vitro assay results demonstrated that pyrrol-2-yl ethanone derivatives can inhibit the proliferation of cancer cells. Therefore, pyrrol-2-yl ethanone derivatives (PM2) can be both LDH-A inhibitor and anticancer agents.

  13. Structure and Raman spectra of pyridyl substituted diketo-pyrrolo-pyrrole isomers and polymorphs

    NASA Astrophysics Data System (ADS)

    Luňák, Stanislav, Jr.; Vyňuchal, Jan; Horáčková, Pavlína; Frumarová, Božena; Žák, Zdirad; Kučerík, Jiří; Salyk, Ota

    2010-11-01

    A complete series of symmetrical and unsymmetrical isomeric pairs of 4- and 2-pyridyl substituted diketo-pyrrolo-pyrroles was synthesized. Both polymorphs of 3,6-bis-(4'-pyridyl)-2,5-dihydro-pyrrolo[3,4- c]pyrrole-1,4-dione were prepared. Asymmetrical 3-phenyl-6-pyridine-2'-yl-2,5-dihydro-pyrrolo[3,4- c]pyrrole-1,4-dione was synthesized for the first time and X-ray structure of its monocrystal was determined. Density functional theory calculations of the ground state geometry were compared with experimental X-ray diffraction data. Theoretical Raman spectra enabled to assign the main peaks of the experimental ones for all four pyridyl DPP derivatives. Crucial spectral features, which reflect the molecular and crystal (H-bond invoked) asymmetry are C dbnd O (pyrrolinone) stretching, N sbnd H (pyrrolinone) bending and trigonal (hetero)aryl bending. Sublimation temperatures of 2-pyridyl derivatives are significantly lower than for 4-pyridyl derivatives, in which stronger in-plane NH(pyrrolinone) sbnd CO(pyrrolinone) intermolecular H-bonding dominates.

  14. Evaluation on the inhibition of pyrrol-2-yl ethanone derivatives to lactate dehydrogenase and anticancer activities.

    PubMed

    Lu, Na-Na; Weng, Zhao-Yue; Chen, Qiu-Yun; Boison, Daniel; Xiao, Xin-Xin; Gao, Jing

    2016-08-01

    Lactate dehydrogenase A (LDH-A) is a potentially important metabolic target for the inhibition of the highly activated glycolysis pathway in cancer cells. In order to develop bifunctional compounds as inhibitor of LDH-A and anticancer agents, two pyrrol-2-yl methanone (or ethanone) derivatives (PM1 and PM2) were synthesized and evaluated as inhibitors of LDH-A based on the enzyme assay and cell assay by spectroscopy analysis. Fluorescence and CD spectra results demonstrated that both the change of second structure of LDH-A and the affinity interaction for compounds to LDH-A gave great effect on the activity of LDH-A. In particular, low concentration of compounds (1μμ-25μμ) could change the level of pyruvate in cancer cells. Moreover, the in vitro assay results demonstrated that pyrrol-2-yl ethanone derivatives can inhibit the proliferation of cancer cells. Therefore, pyrrol-2-yl ethanone derivatives (PM2) can be both LDH-A inhibitor and anticancer agents. PMID:27104676

  15. A reinterpretation of the electronic spectrum of pyrrole: A quantum dynamics study

    SciTech Connect

    Neville, S. P.; Worth, G. A.

    2014-01-21

    The first band in the electronic spectrum of pyrrole is calculated from wavepacket propagations performed using the MCTDH method. To do so, two model Hamiltonians are constructed to describe seven low-lying excited electronic states of pyrrole. These Hamiltonians are based on the vibronic coupling model, and are parameterised via fitting to extensive CASPT2 and EOM-CCSD calculations. A detailed analysis of the structure of pyrrole's electronic spectrum in the range 5.5 to 6.5 eV is made. The role of intensity borrowing from transitions to ππ{sup *} states by lower-lying 3s and 3p Rydberg states is assessed, and reassignments of much of the spectrum are subsequently made which indicate that most of the states in the spectrum are predominantly Rydberg in character. The resulting conclusions drawn serve to highlight the limitations of assignments based on the matching of calculated vertical excitation energies and the positions of peak maxima observed in electronic spectra.

  16. Synthesis, crystal structure and complexing properties of calix[4]pyrrole 10α,20α-disubstituted Schiff bases and urea derivatives

    NASA Astrophysics Data System (ADS)

    Han, Ying; Sun, Juan-Juan; Wang, Gen-Liang; Yan, Chao-Guo

    2015-03-01

    10α,20α-di(4-aminophenyl)calix[4]pyrroles were synthesized from the acid catalyzed cyclization of dialkyldipyrromethanes with p-nitroacetophenone and sequential hydrogenation of nitro group, which in turn reacted with several aromatic aldehydes and pyridinecarboxaldehydes as well as isocyanates to give a series of calix[4]pyrrole 10α,20α-disubstituted Schiff base and urea derivatives. The crystal structures of the newly-formed calix[4]pyrrole Schiff bases were successfully determined by X-ray diffraction. The complexing property of calix[4]pyrrole Schiff bases for transition metal ions was also investigated with UV-Vis spectroscopy.

  17. Synthesis of 1,2,3-Substituted Pyrroles from Propargylamines via a One-Pot Tandem Enyne Cross Metathesis-Cyclization Reaction.

    PubMed

    Chachignon, Helene; Scalacci, Nicolò; Petricci, Elena; Castagnolo, Daniele

    2015-05-15

    Enyne cross metathesis of propargylamines with ethyl vinyl ether enables the one-pot synthesis of substituted pyrroles. A series of substituted pyrroles, bearing alkyl, aryl, and heteroaryl substituents, has been synthesized in good yields under microwave irradiation. The reactions are rapid and procedurally simple and also represent a facile entry to the synthetically challenging 1,2,3-substituted pyrroles. The value of the methodology is further corroborated by the conversion of pyrroles into 3-methyl-pyrrolines and the derivatization of the 3-methyl-substituent arising from the metathesis reaction. PMID:25897951

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

    PubMed

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

    2016-04-01

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

  19. Characterization of a glucose sensor prepared by electropolymerization of pyrroles containing a tris-bipyridine osmium complex.

    PubMed

    Tsujimoto, Masaki; Yabutani, Tomoki; Sano, Atsushi; Tani, Yuji; Murotani, Hiroki; Mishima, Yuji; Maruyama, Kenichi; Yasuzawa, Mikito; Motonaka, Junko

    2007-01-01

    A glucose sensor was developed by electrocopolymerization using pyrroles containing a tris-bipyridine (bpy) osmium complex (Os-py), pyrrole (py), pyrrole propanoic acid (PPA) and glucose oxidase (GOx) to improve the key performance characteristics, such as the sensitivity, selectivity, and long-term stability. Tris-bipyridine osmium pyrrole complexes with four different methylene moieties were utilized to correlate the methylene length with the glucose sensor performance. The electrocatalytic response of glucose was clearly observed at electrodes modified with Os-py, except for the electrode immobilized with the Os-py complex containing the shortest methylene moiety. The current response to glucose increased up to a concentration of 100 mmol dm(-3). The electrocatalytic response to glucose at the [Os(bpy)(2)(py(6)-bpy)](2+/3+)/py/PPA/GOx electrode was stable for more than 100 days. Dissolved oxygen and potential interference compounds (ascorbic acid, uric acid, and acetaminophen) minimally perturbed the current response to glucose at the [Os(DM-bpy)(2)(py(6)-bpy)](2+/3+)/py/PPA/GOx electrode. Based on these results, a longer methylene moiety appears to improve the performance characteristics of a glucose sensor fabricated via the electropolymerization of tris-bipyridine osmium pyrrole complexes. PMID:17213625

  20. Role of the ribose-specific marker furfuryl-amine in the formation of aroma active 1-(furan-2-ylmethyl)-1H-pyrrole (or furfuryl-pyrrole) derivatives.

    PubMed

    Nikolov, Plamen Y; Yaylayan, Varoujan A

    2012-10-10

    Furfuryl-pyrroles possess a diverse range of organoleptic properties described as roasted, chocolaty, green, horseradish-like, and mushroom-like and are detected in various foods such as coffee, chocolate, popcorn, and roasted chicken. Although their origin in food was attributed to furfuryl-amine, the latter has not been detected so far in Maillard model systems or in foods. In this study, furfuryl-amine was shown to be formed specifically from ribose through nitrogen atom transfer from the α-amino group of any amino acid. Such a transfer can be achieved through decarboxylation of the Schiff base adduct and isomerization followed by hydrolysis. Through the use of (15)Nα-lysine it was revealed that only the (15)Nα nitrogen atom was incorporated into its structure, indicating a specific role for the carboxylate moiety in the mechanism of its formation. Furthermore, isotope labeling studies have indicated that furfuryl-pyrrole derivatives can be formed by the interaction of 2 mol of furfuryl-amine with 3-deoxyribosone followed by dehydration and cyclization to form 1-(furan-2-yl)-N-{[1-(furan-2-ylmethyl)-1H-pyrrol-2-yl]methylidene}methanamine. After hydrolysis, this intermediate can generate furfuryl-formyl-pyrrole, furfuryl-pyrrole carboxylic acid, and furfuryl-pyrrole. In this study, the furfuryl-amine derivatives were also detected in different coffee beans after pyrolysis and analysis by GC-MS. The potential of these compounds to form in aqueous model systems at a temperature of 120 °C was also demonstrated. PMID:22994507

  1. Biomimetic synthesis of water-soluble conducting copolymers/homopolymers of pyrrole and 3,4-ethylenedioxythiophene.

    PubMed

    Bruno, Ferdinando F; Fossey, Stephen A; Nagarajan, Subhalakshmi; Nagarajan, Ramaswamy; Kumar, Jayant; Samuelson, Lynne A

    2006-02-01

    A novel biomimetic route for the synthesis of electrically conducting homopolymers/copolymers of pyrrole and 3,4-ethylenedioxythiophene (EDOT) in the presence of a polyelectrolyte, such as polystyrene sulfonate (SPS), is presented. A poly(ethylene glycol)-modified hematin (PEG-hematin) was used to catalyze the homopolymerization of pyrrole and EDOT as well as copolymerization of EDOT and pyrrole in the presence of SPS to yield homopolymers of polypyrrole/SPS and PEDOT/SPS as well as a polypyrrole-co-poly(3,4-ethylenedioxythiophene)/SPS complex. Spectroscopic characterization [UV-visible, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS)], thermal analysis, (TGA), and electrical conductivity studies for these complexes indicated the presence of a stable and electrically conductive form of these polymers. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility. PMID:16471934

  2. Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines.

    PubMed

    Yan, Tao; Barta, Katalin

    2016-09-01

    Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily available alcohol substrates have been recently established; however, these approaches rely on the use of noble metals such as ruthenium or iridium. Here, we report on the direct synthesis of pyrroles using a catalyst based on the earth-abundant and inexpensive iron. The method uses 2-butyne-1,4-diol or 2-butene-1,4-diol that can be directly coupled with anilines, benzyl amines, and aliphatic amines to obtain a variety of N-substituted pyrroles in moderate-to-excellent isolated yields. PMID:27493031

  3. Organic field-effect transistors based on Langmuir-Blodgett films of an extended porphyrin analogue - Cyclo[6]pyrrole

    NASA Astrophysics Data System (ADS)

    Xu, Hai; Wang, Ying; Yu, Gui; Xu, Wei; Song, Yabin; Zhang, Deqing; Liu, Yunqi; Zhu, Daoben

    2005-10-01

    Field-effect transistors using cyclo[6]pyrrole as active layers were prepared by Langmuir-Blodgett (LB) method. Cyclo[6]pyrrole is a porphyrin analogue with an extended π-system(22-π-electron). It could form a stable, reproducible monolayer at the air-water interface, which could be transferred onto a substrate with nearly unity transfer ratio and resulted in multilayer structure with the cyclo[6]pyrrole molecules stacking in a face-to-face configuration due to strong intermolecular π-π interactions. An un-optimized device based on this LB films displayed a mobility of 0.014 cm 2 V -1 s -1, which is higher than the highest value of the devices based on typical porphyrins reported.

  4. Organocatalytic Enantioselective Aza-Friedel-Crafts Reaction of Cyclic Ketimines with Pyrroles using Imidazolinephosphoric Acid Catalysts.

    PubMed

    Nakamura, Shuichi; Matsuda, Nazumi; Ohara, Mutsuyo

    2016-07-01

    Organocatalytic enantioselective aza-Friedel-Crafts reactions of cyclic ketimines with pyrroles or indoles were catalyzed by imidazoline/phosphoric acid catalysts. The reaction was applied to various 3H-indol-3-ones to afford products in excellent yields and enantioselectivities. The chiral catalysts can be recovered by a single separation step using column chromatography and are reusable without further purification. Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction. PMID:27124556

  5. Visible Light Initiated Hantzsch Synthesis of 2,5-Diaryl-Substituted Pyrroles at Ambient Conditions.

    PubMed

    Lei, Tao; Liu, Wen-Qiang; Li, Jian; Huang, Mao-Yong; Yang, Bing; Meng, Qing-Yuan; Chen, Bin; Tung, Chen-Ho; Wu, Li-Zhu

    2016-05-20

    Irradiation of a mixture of enamines and α-bromo ketones, with a catalytic amount of Ir(ppy)3 by visible light (λ = 450 nm), enables the production of various 2,5-diaryl-substituted pyrroles in good to excellent yields. The key intermediates in this reaction have been identified as alkyl radicals, generated from single-electron transfer from the photoexcited Ir(ppy)3* to α-bromo ketones, which subsequently react with a broad range of enamines to undergo the Hantzsch reaction rapidly at ambient conditions. PMID:27199225

  6. Synthesis of Substituted Pyrroles via Copper-Catalyzed Cyclization of Ethyl Allenoates with Activated Isocyanides.

    PubMed

    Lu, Kui; Ding, Fang; Qin, Long; Jia, Xiaoliang; Xu, Chuanming; Zhao, Xia; Yao, Qingwei; Yu, Peng

    2016-08-01

    A new method for the synthesis of di- and trisubstituted pyrroles via copper-catalyzed cyclization of ethyl allenoates with activated isocyanides has been developed. In contrast to related annulation reactions previously reported, this new process features a skeletal rearrangement in which the aryl sulfonyl moiety, which functions as the electron-withdrawing group in the α-carbon of the isocyanide, was found to migrate to the γ-carbon of the starting allenoate in the final product for the first time. PMID:27348611

  7. Ac conduction in conducting poly pyrrole-poly vinyl methyl ether polymer composite materials

    SciTech Connect

    Saha, S.K.; Mandal, T.K.; Mandal, B.M.; Chakravorty, D.

    1997-03-01

    Composite materials containing conducting polypyrrole and insulating poly (vinyl methyl ether) (PVME) have been synthesized by oxidative polymerization of pyrrole in ethanol using FeCl{sub 3} oxidant in the presence of PVME. The ac conductivity measurements have been carried out in the frequency range of 100 Hz to 10 MHz and in the temperature range of 110 to 350 K. The frequency dependent conductivity has been explained on the basis of a small polaron tunnelling mechanism. {copyright} {ital 1997 American Institute of Physics.}

  8. N-[1-(1H-Pyrrol-2-yl)ethyl­idene]aniline

    PubMed Central

    Su, Bi-Yun; Li, Lei; Wang, Jia-Xiang; Li, Xuan-Yan

    2012-01-01

    There are two independent mol­ecules in the asymmetric unit of the title compound, C12H12N2, in which the pyrrole and benzene rings form dihedral angles of 72.37 (7) and 82.34 (8)°. The imino N—C bond lengths in the two mol­ecules are equal [1.286 (2) Å] and indicate C=N character. In the crystal, each mol­ecule forms a dimer with an inversion-related mol­ecule through a pair of classical N—H⋯N hydrogen bonds. PMID:23125684

  9. The effect of relative humidity on the detection of pyrrole by PTR-MS for OH reactivity measurements

    NASA Astrophysics Data System (ADS)

    Sinha, V.; Custer, T. G.; Kluepfel, T.; Williams, J.

    2009-04-01

    The hydroxyl radical (OH) is the most important atmospheric oxidant. Recently Sinha et al. [1] developed a new method to measure the total OH reactivity of ambient air (OH sink) employing a proton transfer reaction mass spectrometer (PTR-MS) as a detector. The new method uses pyrrole (C4H4NH) as a reagent and for an OH reactivity measurement this species must be measured under both dry (~ 0% RH) and humid air ( > 30% RH). Here, we investigate the sensitivity dependence of the PTR-MS for pyrrole, as a function of relative humidity in the sampled air. Various normalizations with respect to the H3O+ ion and its different hydrated clusters ions H3O+(H2O)n=1,2,3 are compared. It is shown that both the primary ion signal (H3O+ ion m/z = 19) and the first water cluster ion H3O+(H2O) (m/z = 37) should be used for pyrrole quantification. However, in spite of using this normalization, the PTR-MS sensitivity for pyrrole changes by as much as 16 % between dry (~ 0% RH) and humid air (above 30 % RH), with higher sensitivity when the sampled air is humid. Thus, for accurate quantification of pyrrole using a PTR-MS, calibration factors appropriate to dry and humid air should be employed. We recommend that humidity dependence of the PTR-MS be taken into account when reactivity measurements are performed using the pyrrole based comparative reactivity method (CRM). [1]. V. Sinha, J. Williams, J.N. Crowley, and J. Lelieveld, Atmos. Chem. Phys. 8 (2008) 2213-2227

  10. The effect of relative humidity on the detection of pyrrole by PTR-MS for OH reactivity measurements

    NASA Astrophysics Data System (ADS)

    Sinha, V.; Custer, T. G.; Kluepfel, T.; Williams, J.

    2009-05-01

    The hydroxyl radical (OH) is the most important atmospheric oxidant. Recently Sinha et al. [V. Sinha, J. Williams, J.N. Crowley, J. Lelieveld, Atmos. Chem. Phys. 8 (2008) 2213] developed a new method to measure the total OH reactivity of ambient air (OH sink) employing a proton transfer reaction mass spectrometer (PTR-MS) as a detector. The new method uses pyrrole (C4H4NH) as a reagent and for an OH reactivity measurement this species must be measured under both dry (~0% RH) and humid air (>30% RH). Here, we investigate the sensitivity dependence of the PTR-MS for pyrrole, as a function of relative humidity in the sampled air. Various normalizations with respect to the H3O+ ion and its different hydrated cluster ions H3O+(H2O)n=1,2,3 are compared. It is shown that both the primary ion signal (H3O+ ion m/z = 19) and the first water cluster ion H3O+(H2O) (m/z = 37) should be used for pyrrole quantification. However, in spite of using this normalization, the PTR-MS sensitivity for pyrrole changes by as much as 16% between dry (~0% RH) and humid air (above 30% RH), with higher sensitivity when the sampled air is humid. Thus, for accurate quantification of pyrrole using a PTR-MS, calibration factors appropriate to dry and humid air should be employed. We recommend that humidity dependence of the PTR-MS be taken into account when reactivity measurements are performed using the pyrrole based comparative reactivity method (CRM).

  11. Synthesis of furans and pyrroles via migratory and double migratory cycloisomerization reactions of homopropargylic aldehydes and imines

    PubMed Central

    Shiroodi, Roohollah Kazem; Vera, Claudia I. Rivera; Dudnik, Alexander S.; Gevorgyan, Vladimir

    2015-01-01

    A novel gold-catalyzed divergent sysnthesis of furans and pyrroles employing readily available homopropargylic aldehydes and imines have been developed. The regiochemical outcome of this reaction is dependent on the substituent on the terminal alkyne of substrate. Thus, substrates possessing alkyl and aryl substituent at the alkyne moiety produce 2,3,5-substituted furans and pyrroles via a migratory cycloisomerizaton reaction. Whereas, their silicon analogues are capable to undergo a double migratory process leading to 2,3,4-substituted heterocycles. PMID:26185336

  12. Properties of poly(ethylene terephthalate) track membranes with a polymer layer obtained by plasma polymerization of pyrrole vapors

    NASA Astrophysics Data System (ADS)

    Kravets, L.; Dmitriev, S.; Lizunov, N.; Satulu, V.; Mitu, B.; Dinescu, G.

    2010-03-01

    The structure and the charge transport properties of poly(ethylene terephthalate) track membrane modified by pyrrole plasma were studied. It was found that polymer deposition on the surface of a track membrane via plasma polymerization of pyrrole results in the creation of composite nanomembranes that, in the case of the formation of a semipermeable layer, possess asymmetric conductivity in electrolyte solutions - a rectification effect similar to that of a p-n junction in semiconductors. It is caused by presence in the membranes of two layers with different functional groups and also by the pore geometry. Such membranes can be used to create chemical and biochemical sensors.

  13. The Organocatalytic Approach to Enantiopure 2H- and 3H-Pyrroles: Inhibitors of the Hedgehog Signaling Pathway.

    PubMed

    Kötzner, Lisa; Leutzsch, Markus; Sievers, Sonja; Patil, Sumersing; Waldmann, Herbert; Zheng, Yiying; Thiel, Walter; List, Benjamin

    2016-06-27

    A divergent approach to enantioenriched 2H- and 3H-pyrroles catalyzed by a spirocyclic phosphoric acid is reported that makes use of a Fischer-type indolization and a [1,5]-alkyl shift. Catalyzed by the chiral phosphoric acid STRIP, good to excellent yields and enantioselectivities could be obtained. Remarkably, biological evaluation reveals one of these novel 2H-pyrroles to be a potent but nontoxic inhibitor of the Hedgehog signaling pathway by binding to the Smoothened protein. PMID:27239757

  14. Biological activity of two new pyrrole derivatives against stored-product species: influence of temperature and relative humidity.

    PubMed

    Boukouvala, M C; Kavallieratos, N G; Athanassiou, C G; Hadjiarapoglou, L P

    2016-08-01

    Members of the pyrrole group are likely to have interesting properties that merit additional investigation as insecticides at the post-harvest stages of agricultural commodities. In the present work, the insecticidal effect of two new pyrrole derivatives, ethyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3i) and isopropyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3k) were studied as stored-wheat protectants against two major stored-product insect species, the confused flour beetle, Tribolium confusum Jaquelin du Val adults and larvae and the Mediterranean flour moth, Ephestia kuehniella Zeller larvae at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days), temperatures (20, 25 and 30°C) and relative humidity (55 and 75%) levels. For T. confusum adults, in the case of the pyrrole derivative 3i, mortality was low and it did not exceed 32.2% in wheat treated with 10 ppm 3i at 30°C and 55% relative humidity. Progeny production was very low (<1 individual/vial) in all combinations of 55% relative humidity, including control. In the case of the pyrrole derivative 3k, mortality reached 67.8% at 30°C and 55% relative humidity in wheat treated with 10 ppm after 21 days of exposure. Progeny production was low in all tested combinations (≤0.7 individuals/vial) of 55% relative humidity, including control. For T. confusum larvae, in the case of the pyrrole derivative 3i, at the highest dose, mortality was 82.2% at 25°C and 55% relative humidity whereas in the case of 3k it reached 77.8% at the same combination. In contrast, mortality at 75% relative humidity remained very low and did not exceed 13.3%. For E. kuehniella larvae, the highest mortalities, 44.4 and 63.3%, were observed in 10 ppm at 25°C and 55% relative humidity for both pyrrole derivatives. The compounds tested here have a certain insecticidal effect, but this effect is moderated by the exposure

  15. Experimental Charge Density Studies of Disordered N-Phenylpyrrole and N-(4-Fluorophenyl)pyrrole

    NASA Astrophysics Data System (ADS)

    Meindl, Kathrin; Henn, Julian; Kocher, Nikolaus; Leusser, Dirk; Zachariasse, Klaas A.; Sheldrick, George M.; Koritsanszky, Tibor; Stalke, Dietmar

    2009-08-01

    The static electron densities of the title compounds were extracted from high-resolution X-ray diffraction data using the nucleus-centered finite multipole expansion technique. The interpretation of the data collected for the N-phenylpyrrole crystal revealed a static disorder that could be successfully resolved within the aspherical-atom formalism. The local and integrated topological properties of the density obtained via a constrained multipole refinement are in statistical agreement with those calculated at the B3LYP/cc-pVTZ level of theory for the isolated molecule and for those derived from the experimental density of the para-fluorinated derivative N-(4-fluorophenyl)pyrrole. The topological analysis of the densities indicates neither pyramidal character of the pyrrole N-atom nor a quinoidal structure of the phenyl rings in either molecule. The fluorine substitution appears to have only a minor effect on the density of the remaining constituents but it results in markedly different features of the electrostatic potential of the two compounds. The consistency of the multipole refinement is validated by residual density analysis.

  16. Synthesis and structures of transition metal pacman complexes of heteroditopic Schiff-base pyrrole macrocycles.

    PubMed

    Leeland, James W; Finn, Colin; Escuyer, Bérengère; Kawaguchi, Hiroyuki; Nichol, Gary S; Slawin, Alexandra M Z; Love, Jason B

    2012-12-01

    A series of polydentate dual-compartment, Schiff-base pyrrole macrocycles has been prepared through the straightforward Lewis acid catalysed [1 + 1] condensation reactions between ONO or O(5)-linked aryldiamines and dipyrromethane dialdehydes. These macrocycles display hydrogen-bond acceptor and donor properties and provide distinct N(4) and O(5)/ONO donor sets for metallation reactions, so forming alkali, alkaline earth, and transition metal complexes that were characterised spectroscopically and crystallographically. While the conformationally flexible O(5) donor set allows the formation of helical potassium salt structures, the transition metal complexes of all variants of these macrocycles invariably adopt wedged, Pacman-shaped structures in which the metal is bound in the pyrrole-imine N(4) donor set, so leaving the ONO/O(5) donor set pendant and apical. In some cases (V, Cr, and Co), this proximate combination of Lewis acid binding site and hydrogen bond acceptor facilitates the coordination of water within the molecular cleft; alternatively, direct interaction between the pendant arm and the metal is seen (e.g. Ti). Higher order [2 + 2] macrocycles were also prepared as minor, inseparable by-products of cyclisation, and Fe(2), Mn(2), and Co(2) complexes of these larger macrocycles were found to adopt binuclear helical structures by X-ray crystallography. PMID:23026851

  17. Adsorption and thermal dissociation of pyrrole on Si(1 0 0)-2 × 1

    NASA Astrophysics Data System (ADS)

    Qiao, Ming-Hua; Tao, Feng; Cao, Yong; Xu, Guo-Qin

    2003-10-01

    The adsorption and thermal reaction of pyrrole on Si(1 0 0)-2 × 1 have been studied using X-ray and ultra-violet photoelectron spectroscopies (XPS and UPS) and high resolution electron energy loss spectroscopy (HREELS). At low exposures, Pyrrole chemisorbs molecularly at 120 K with its ring parallel to the surface via the π-interaction. The increase in coverage causes tilting of chemisorbed molecules towards the surface normal, attributable to the adsorbate-adsorbate interactions. At ˜350 K, the N-H bond scission of the π-bonded species occurs, resulting in Si-H and vertically N-bonded pyrrolyl on the surface. The pyrrolyl species is thermally stable to 700 K. Compared to furan or thiophene on Si(1 0 0), this higher thermal stability is ascribed to the passivation effect of the H-atoms from N-H bond dissociation and the less strain within the pyrrolyl-substrate complex. Further annealing to 900 K results in the formation of silicon carbide and silicon nitride on the substrate.

  18. Magnetic Circular Dichroism Spectroscopy of meso-Tetraphenylporphyrin-Derived Hydroporphyrins and Pyrrole-Modified Porphyrins.

    PubMed

    Rhoda, Hannah M; Akhigbe, Joshua; Ogikubo, Junichi; Sabin, Jared R; Ziegler, Christopher J; Brückner, Christian; Nemykin, Victor N

    2016-07-28

    A large set of free-base and transition-metal 5,10,15,20-tetraphenyl-substituted chlorins, bacteriochlorins, and isobacteriochlorins and their pyrrole-modified analogues were investigated by combined UV-visible spectroscopy, magnetic circular dichroism (MCD), density functional theory (DFT), and time-dependent DFT (TDDFT) approaches and their spectral characteristics were compared to those of the parent compounds, free-base tetraphenylporphyrin 1H2 and chlorin 2H2. It was shown that the nature of the pyrroline substituents in the chlorin derivatives dictates their specific UV-vis and MCD spectroscopic signatures. In all hydroporphyrin-like cases, MCD spectroscopy suggests that the ΔHOMO is smaller than the ΔLUMO for the macrocycle-centered frontier molecular orbitals. DFT and TDDFT calculations were able to explain the large broadening of the UV-vis and MCD spectra of the chlorin diones and their derivatives compared to the other hydroporphyrins and hydroporphyrin analogues. This study contributes to the further understanding of the electronic effects of replacing a pyrrole in porphyrins by pyrrolines or other five-membered heterocycles (oxazoles and imidazoles). PMID:27400337

  19. Pyrrole-hyaluronic acid conjugates for decreasing cell binding to metals and conducting polymers

    PubMed Central

    Lee, Jae Young; Schmidt, Christine E.

    2010-01-01

    Surface modification of electrically conductive biomaterials has been studied to improve biocompatibility for a number of applications, such as implantable sensors and microelectrode arrays. In this study, we electrochemically coated electrodes with biocompatible and non-cell adhesive hyaluronic acid (HA) to reduce cellular adhesion for potential use in neural prostheses. To this end, pyrrole-conjugated hyaluronic acid (PyHA) was synthesized and employed for electrochemical coating of platinum, indium-tin-oxide, and polystyrene sulfonate-doped polypyrrole electrodes. This PyHA conjugate consists of (1) a pyrrole moiety that allows the compound to be electrochemically deposited onto a conductive substrate and (2) non-adhesive HA to minimize cell adhesion and to potentially decrease inflammatory tissue responses. Our characterization results showed the presence of a hydrophilic p(PyHA) layer on the modified electrode, and impedance measurements revealed impedance that was statistically the same as the unmodified electrode. We found that the p(PyHA)-coated electrodes minimized adhesion and migration of fibroblasts and astrocytes for a minimum of up to 3 months. Also, the coating was stable in physiological solution for 3 months and also stable against enzymatic degradation by hyaluronidase. These studies suggest that this p(PyHA)-coating has the potential to be used to mask conducting electrodes from adverse glial responses that occur upon implantation. In addition, electrochemical coating with PyHA can be potentially extended for the surface modification of other metallic and conducting substances such as stents and biosensors. PMID:20558330

  20. A comparative study of the aromaticity of pyrrole, furan, thiophene, and their aza-derivatives.

    PubMed

    Najmidin, Kalbinur; Kerim, Ablikim; Abdirishit, Paruza; Kalam, Horigul; Tawar, Tursungul

    2013-09-01

    The relative aromaticity of pyrrole, furan, thiophene, and their aza-derivatives has been examined using TRE (topological resonance energy), MRE (magnetic resonance energy), ring current (RC), and ring current diamagnetic susceptibility (χG) methods. The results obtained were compared with results obtained by others who used the energetic method ASE (aromatic stabilization energy), the geometric method HOMA (harmonic oscillator model of aromaticity), and the magnetic method NICS(1) (nucleus-independent chemical shift). The impact of nitrogen atoms on the aromaticity of the aza-derivatives of pyrrole, furan, and thiophene is discussed. An excellent correlation was found between the energetic (TRE, MRE) and magnetic (RC and χG) criteria of aromaticity for all compounds. It was expected that inclusion of a heteroatom would decrease the aromaticity relative to the cyclopentadienyl anion. Our results show that the type of the first heteroatom, which donates two electrons to the system, as well as the number of nitrogen atoms and their positions in the molecule have a strong effect on aromaticity. In general, aromaticity is enhanced when the nitrogen atom is adjacent to the first heteroatom. The magnitude of aromaticity is related closely with the uniformity of distribution of π-electrons in the molecule. PMID:23716174

  1. Dynamics starting at a conical intersection: Application to the photochemistry of pyrrole

    SciTech Connect

    Sellner, Bernhard; Barbatti, Mario; Lischka, Hans

    2009-07-14

    The photochemical ring opening process in pyrrole has been investigated by performing classical on-the-fly dynamics using the multiconfiguration self-consistent field method for the computation of energies and energy gradients. As starting point for the dynamics the conical intersection corresponding to the ring-puckered ring-opened structure, determined previously [Barbatti et al., J. Chem. Phys. 125, 164323 (2006)], has been chosen. Two sets of initial conditions for the nuclear velocities were constructed: (i) nuclear velocities in the branching (g,h) plane of the conical intersection and (ii) statistical distribution for all atoms. Both sets of initial conditions show very similar results. Reactive trajectories are only found in a very limited sector in the (g,h) plane and reaction products are very similar. Within the simulation time of 1 ps, ring opening of pyrrole to the biradical NH=CH-CH-CH=CH chain followed by ring closure to a substituted cyclopropene structure (NH=CH-C{sub 3}H{sub 3}) is observed. The computed structural data correlate well with the experimentally observed dissociation products.

  2. The Breaking and Mending of meso-Tetraarylporphyrins: Transmuting the Pyrrolic Building Blocks.

    PubMed

    Brückner, Christian

    2016-06-21

    Naturally occurring porphyrins and hydroporphyrins vary with respect to their ring substituents and oxidation states, but their tetrapyrrolic frameworks remain fully preserved across all kingdoms of life; there are no naturally occurring porphyrin-like macrocycles known that contain nonpyrrolic building blocks. However, the study of porphyrin analogues in which one or two pyrroles were replaced with nonpyrrolic building blocks might shed light on the correlation between structural modulation and ground and excited state optical properties of the "pigments of life", unlocking their mechanisms of function. Also, porphyrinoids with strong absorbance and emission spectra in the NIR are sought after in technical (e.g., light-harvesting) and biomedical (e.g., imaging and photochemotherapy) applications. These porphyrin analogues, the so-called pyrrole-modified porphyrins (PMPs), are synthetically accessible using total syntheses. Alternatively-and most handily-they can also be formed by conversion of synthetic porphyrins. Guided by older reports of the fortuitous modifications of porphyrins into PMPs, our research program generalized the so-dubbed "Breaking and Mending of Porphyrins" approach toward PMPs. This method to convert a pyrrole in meso-tetraarylporphyrins to a nonpyrrolic building block with high precision relies on a number of distinct steps. Step 1: The porphyrin is functionalized in a way that activates one or two peripheral double bonds toward breakage; in all cases surveyed here, this step is an osmium tetroxide-mediated dihydroxylation to generate dihydroxychlorin and tetrahydroxybacteriochlorins. Step 2: The activated, dihydroxylated β,β'-bond is "broken". Step 3: The functional groups resulting from the ring-cleavage reactions are utilized in subsequent "mending" steps to form the PMPs, that themselves may be subject to further modifications, Step 4. Thus, PMPs in which a pyrrole was degraded to an imine linkage, contracted to a four-membered ring, or

  3. Assessment of conformational, spectral, antimicrobial activity, chemical reactivity and NLO application of Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone).

    PubMed

    Rawat, Poonam; Singh, R N

    2015-04-01

    An orange colored pyrrole dihydrazone: Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone) (PDBO) has been synthesized by reaction of oxalic acid dihydrazide with 2,5 diformyl-1H-pyrrole and has been characterized by spectroscopic analysis (1H, 13C NMR, UV-visible, FT-IR and DART Mass). The properties of the compound has been evaluated using B3LYP functional and 6-31G(d,p)/6-311+G(d,p) basis set. The symmetric (3319, 3320 cm(-1)) and asymmetric (3389, 3382 cm(-1)) stretching wave number confirm free NH2 groups in PDBO. NBO analysis shows, inter/intra molecular interactions within the molecule. Topological parameters have been analyzed by QTAIM theory and provide the existence of intramolecular hydrogen bonding (N-H⋯O). The local reactivity descriptors analyses determine the reactive sites within molecule. The calculated first hyperpolarizability value (β0=23.83×10(-30) esu) of pyrrole dihydrazone shows its suitability for non-linear optical (NLO) response. The preliminary bioassay suggested that the PDBO exhibits relatively good antibacterial and fungicidal activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Aspergillus niger. The local reactivity descriptors--Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analyses have been used to determine the reactive sites within molecule. PMID:25615679

  4. A Guided Inquiry Experiment for the Measurement of Activation Energies in the Biophysical Chemistry Laboratory: Decarboxylation of Pyrrole-2-Carboxylate

    ERIC Educational Resources Information Center

    Hutchinson, Kelly M.; Bretz, Stacey Lowery; Mettee, Howard D.; Smiley, Jeffrey A.

    2005-01-01

    A laboratory experiment for undergraduate biophysical chemistry is described, in which the acid concentration and temperature dependences of the decarboxylation of pyrrole-2-carboxylate are measured using a continuous ultraviolet (UV) spectrophotometric assay. Data collection and analysis are structured using principles of guided inquiry. Data…

  5. Assessment of conformational, spectral, antimicrobial activity, chemical reactivity and NLO application of Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone)

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-04-01

    An orange colored pyrrole dihydrazone: Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone) (PDBO) has been synthesized by reaction of oxalic acid dihydrazide with 2,5 diformyl-1H-pyrrole and has been characterized by spectroscopic analysis (1H, 13C NMR, UV-visible, FT-IR and DART Mass). The properties of the compound has been evaluated using B3LYP functional and 6-31G(d,p)/6-311+G(d,p) basis set. The symmetric (3319, 3320 cm-1) and asymmetric (3389, 3382 cm-1) stretching wave number confirm free NH2 groups in PDBO. NBO analysis shows, inter/intra molecular interactions within the molecule. Topological parameters have been analyzed by QTAIM theory and provide the existence of intramolecular hydrogen bonding (N-H⋯O). The local reactivity descriptors analyses determine the reactive sites within molecule. The calculated first hyperpolarizability value (β0 = 23.83 × 10-30 esu) of pyrrole dihydrazone shows its suitability for non-linear optical (NLO) response. The preliminary bioassay suggested that the PDBO exhibits relatively good antibacterial and fungicidal activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Aspergillus niger. The local reactivity descriptors - Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analyses have been used to determine the reactive sites within molecule.

  6. Nano-copper catalysed highly regioselective synthesis of 2,4-disubstituted pyrroles from terminal alkynes and isocyanides.

    PubMed

    Tiwari, Dipak Kumar; Pogula, Jaya; Sridhar, B; Tiwari, Dharmendra Kumar; Likhar, Pravin R

    2015-09-14

    Nano-copper(0) stabilized on alumina prepared from Cu-Al hydrotalcite has been reported for completely regioselective synthesis of 2,4-disubstituted pyrroles from unactivated terminal aromatic/aliphatic alkynes and isocyanides. The reaction is operationally simple, involves ligand-free inexpensive nano-copper, and affords products in high yields. PMID:26226177

  7. Sulfur-containing hetero-calix[4]pyrroles as mercury(II) cation-selective receptors: thermodynamic aspects.

    PubMed

    de Namor, Angela F Danil; Abbas, Ismail

    2007-05-31

    Two sulfur-containing hybrid calix[4]pyrrole derivatives (III and IV) have been synthesized and fully characterized. Several analytical techniques (1H NMR, conductance measurements, UV-vis spectrophotometry, titration potentiometry, and titration calorimetry) have been used to assess the interaction between these hybrid calixpyrrole receptors and metal cations in acetonitrile and dimethylsulfoxide. The partition constants of calix[4]pyrrole, I, II, and IV in the acetonitrile-hexane solvent system and the solubilities of the ligands in various solvents at 298.15 K were determined. 1H NMR measurements reveal the sites of interaction of calixpyrrole ligands with metal cations in CD3CN. Conductance and UV-vis spectrophotometric measurements were performed to establish the composition of mercury(II) calixpyrrole complexes in acetonitrile at 298.15 K. Titration calorimetry was used to quantitatively assess Hg(II)-calixpyrrole interactions. Thus the thermodynamics of complexation of calixpyrrole ligands with the mercury(II) cation in acetonitrile at 298.15 K are reported. Potentiometric titrations were also used to establish the stepwise stability constants for the complexation of calix[3]thieno[1]pyrrole with the Hg(II) cation in acetonitrile at 298.15 K. The results show that replacement of one or more pyrrole units by thiophene rings in calix[4]pyrrole has tuned significantly the discrimination ability of these ligands between anions and enables the produced hybrid calixpyrroles to bind selectively with Hg(II) in acetonitrile. No interaction was observed between these ligands and other metal cations in acetonitrile. PMID:17477564

  8. Ethynyl-linked (pyreno)pyrrole-naphthyridine and aniline-naphthyridine molecules as fluorescent sensors of guanine via multiple hydrogen bondings.

    PubMed

    Lu, Shao-Hung; Selvi, Srinivasan; Fang, Jim-Min

    2007-01-01

    New fluorescent molecular sensors for 9-alkylguanines were constructed by conjugation of 2-acetamido-1,8-naphthyridine with N-Boc-pyrrole, N-Boc-pyreno[2,1-b]pyrrole, or acetanilide moieties via an ethynyl bridge. In combination with the triple hydrogen-bonding motif of 2-acetamidonaphthyridine toward alkylguanine, an additional binding site was provided by the substituent properly located on the pyrrole or aniline ring to enhance the affinity of these receptor molecules. Besides the ESI-MS analyses, the binding events were readily monitored by the absorption and fluorescence changes in the visible region. PMID:17194089

  9. A Practical Route to Substituted 7-Aminoindoles from Pyrrole-3-carboxaldehydes

    PubMed Central

    2015-01-01

    Among privileged structures, indoles occupy a central place in medicinal chemistry and alkaloid research. Here we report a flexible and efficient conversion of pyrrole-3-carboxaldehydes to substituted 7-amino-5-cyanoindoles. Phosphine addition to fumaronitrile proceeds with prototropic rearrangement of the initially formed zwitterion to the thermodynamically favored phosphonium ylide, which is poised for in situ Wittig olefination. The predominantly E-alkene product positions the allylic nitrile for facile intramolecular Hoeben–Hoesch reaction in the presence of BF3·OEt2. Syntheses of 2,5- and 3,5-disubstituted 7-aminoindoles are illustrated. Additionally, dianion alkylation of the allylic nitrile is demonstrated to furnish, after cyclization, 5,6-disubstituted 7-aminoindoles to further exemplify this scalable and high-yielding method. PMID:25479249

  10. Lack of effect of deferoxamine, dimethyl sulfoxide, and catalase on monocrotaline pyrrole pulmonary injury

    SciTech Connect

    Bruner, L.H.; Johnson, K.; Carpenter, L.J.; Roth, R.A.

    1987-01-01

    Monocrotaline pyrrole (MCTP) is a reactive metabolite of the pyrrolizidine alkaloid monocrotaline. MCTP given intravenously to rats causes pulmonary hypertension and right ventricular hypertrophy. Lesions in lungs after MCTP treatment contain macrophages and neutrophils, which may contribute to the damage by generation of reactive oxygen metabolites. Rats were treated with MCTP and agents known to protect against oxygen radical-mediated damage in acute models of neutrophil-dependent lung injury. Rats received MCTP and deferoxamine mesylate (DF), dimethyl sulfoxide (DMSO), or polyethylene glycol-coupled catalase (PEG-CAT). MCTP/vehicle-treated controls developed lung injury manifested as increased lung weight, release of lactate dehydrogenase into the airway, and sequestration of SVI-labeled bovine serum albumin in the lungs. Cotreatment of rats with DF, DMSO, or PEG-CAT did not protect against the injury due to MCTP. These results suggest that toxic oxygen metabolites do not play an important role in the pathogenesis of MCTP-induced pulmonary injury.

  11. Depopulation of Single-Phthalocyanine Molecular Orbitals upon Pyrrolic-Hydrogen Abstraction on Graphene.

    PubMed

    Néel, Nicolas; Lattelais, Marie; Bocquet, Marie-Laure; Kröger, Jörg

    2016-02-23

    Single-molecule chemistry with a scanning tunneling microscope has preponderantly been performed on metal surfaces. The molecule-metal hybridization, however, is often detrimental to genuine molecular properties and obscures their changes upon chemical reactions. We used graphene on Ir(111) to reduce the coupling between Ir(111) and adsorbed phthalocyanine molecules. By local electron injection from the tip of a scanning tunneling microscope the two pyrrolic H atoms were removed from single phthalocyanines. The detachment of the H atom pair induced a strong modification of the molecular electronic structure, albeit with no change in the adsorption geometry. Spectra and maps of the differential conductance combined with density functional calculations unveiled the entire depopulation of the highest occupied molecular orbital upon H abstraction. Occupied π states of intact molecules are proposed to be emptied via intramolecular electron transfer to dangling σ states of H-free N atoms. PMID:26812093

  12. Pyrrolo-[3,2-b]pyrroles for Photochromic Analysis of Halocarbons.

    PubMed

    Wu, Jia-Ying; Yu, Cheng-Han; Wen, Jung-Jung; Chang, Chiou-Ling; Leung, Man-kit

    2016-01-19

    Dramatic photochromic-change of 2,5-bis(triphenylamine)-substituted N,N'-diphenylpyrrolo-[3,2-b]pyrrole (1) with halocarbons provides an effective route for halocarbon analysis with the naked eye. The visual detection range can reach as low as 10(-4) ∼ 10(-5) M (1-10 ppm) in CH3CN. This method can also be applied for detection of CHCl3 in water. Fabrication of a disposable paper test cartridge along with using a camera flash as the light source allows on-site halocarbon detection in seconds. Quantitative analysis for CHCl3 and CH2Cl2 have also been demonstrated. PMID:26674846

  13. Telomere Visualization in Tissue Sections using Pyrrole-Imidazole Polyamide Probes.

    PubMed

    Sasaki, Asuka; Ide, Satoru; Kawamoto, Yusuke; Bando, Toshikazu; Murata, Yukinori; Shimura, Mari; Yamada, Kazuhiko; Hirata, Akiyoshi; Nokihara, Kiyoshi; Hirata, Tatsumi; Sugiyama, Hiroshi; Maeshima, Kazuhiro

    2016-01-01

    Pyrrole-Imidazole (PI) polyamides bind to specific DNA sequences in the minor groove with high affinity. Specific DNA labeling by PI polyamides does not require DNA denaturation with harsh treatments of heat and formamide and has the advantages of rapid and less disruptive processing. Previously, we developed tandem hairpin PI polyamide probes (TH59 series), which label telomeres in cultured cell lines more efficiently than conventional methods, such as fluorescence in situ hybridization (FISH). Here, we demonstrate that a TH59 derivative, HPTH59-b, along with immunostaining for specifying cell types in the tissues, visualizes telomeres in mouse and human tissue sections. Quantitative measurements of telomere length with single-cell resolution suggested shorter telomeres in the proliferating cell fractions of tumor than in non-tumor tissues. Thus, PI polyamides are a promising alternative for telomere labeling in clinical research, as well as in cell biology. PMID:27380936

  14. State-specific tunneling lifetimes from classical trajectories: H-atom dissociation in electronically excited pyrrole

    NASA Astrophysics Data System (ADS)

    Xie, Weiwei; Domcke, Wolfgang; Farantos, Stavros C.; Grebenshchikov, Sergy Yu.

    2016-03-01

    A trajectory method of calculating tunneling probabilities from phase integrals along straight line tunneling paths, originally suggested by Makri and Miller [J. Chem. Phys. 91, 4026 (1989)] and recently implemented by Truhlar and co-workers [Chem. Sci. 5, 2091 (2014)], is tested for one- and two-dimensional ab initio based potentials describing hydrogen dissociation in the 1B1 excited electronic state of pyrrole. The primary observables are the tunneling rates in a progression of bending vibrational states lying below the dissociation barrier and their isotope dependences. Several initial ensembles of classical trajectories have been considered, corresponding to the quasiclassical and the quantum mechanical samplings of the initial conditions. It is found that the sampling based on the fixed energy Wigner density gives the best agreement with the quantum mechanical dissociation rates.

  15. Crystal structure of 1-benzyl-4-formyl-1H-pyrrole-3-carb-oxamide.

    PubMed

    Zhong, Qi-Di; Hu, Sheng-Quan; Yan, Hong

    2016-02-01

    In the title compound, C13H12N2O2 (I), the mean planes of the pyrrole and benzyl rings are approximately perpendicular, forming a dihedral angle of 87.07 (4) °. There is an intra-molecular N-H⋯O hydrogen bond forming an S(7) ring motif. In the crystal, mol-ecules are linked via a pair of N-H⋯O hydrogen bonds forming inversion dimers. C-H⋯O hydrogen bonds link the dimers into chains along direction [10-1]. The chains are further linked by weak C-H⋯π inter-actions forming layers parallel to the ac plane. PMID:26958371

  16. Indo Mo calculations of the electronic structures of pyrrole, imidazole, and derivatives

    NASA Astrophysics Data System (ADS)

    Pachler, Klaus G. R.; Pachter, Ruth

    INDO MO calculations on a series of N-substituted pyrroles and imidazoles have been analysed for substituent effects. Some of the basic characteristics of the σ I and or parameters are reflected in the calculated electron densities of the compounds studied. For example, good correlations are obtained between Δ qσN(1)/ΣΔ qσ parameters and σ I for the —R substituted compounds, as well as between ΣΔ qπ values and σ Ro for the +R derivatives. The +R substituents lead to an increased localization of the π-bonds, whereas —R substituted derivatives show an increased delocalization, i.e., the π-bond orders across C(2)-C(3) [or C(2)-N(3)] and C(4)-C(5) decrease and those across other bonds in the ring increase.

  17. Novel composite materials synthesized by the high-temperature interaction of pyrrole with layered oxide matrices

    NASA Astrophysics Data System (ADS)

    Pavel, Alexandru Cezar

    The initial goal of the research presented herein was to develop the very first synthetic metal---high-temperature superconductor ceramic composite material, in the specific form of a polypyrrole---Bi2Sr2CaCu 2O8+delta nanocomposite. In the course of scientific investigation, this scope was broadened to encompass structurally and compositionally similar layered bismuthates and simpler layered oxides. The latter substrates were prepared through novel experimental procedures that enhanced the chance of yielding nanostructured morphologies. The designed novel synthesis approaches yielded a harvest of interesting results that may be further developed upon their dissemination in the scientific community. High-temperature interaction of pyrrole with molybdenum trioxide substrates with different crystalline phases and morphologies led to the formation of the first members of a new class of heterogeneous microcomposites characterized by incomplete occupancy by the metal oxide core of the volume encapsulated by the rigid, amorphous permeable polymeric membrane that reproduces the volume of the initial grain of precursor substrate. The method may be applied for various heterogeneous catalyst substrates for the precise determination of the catalytically active crystallographic planes. In a different project, room-temperature, templateless impregnation of molybdenum trioxide substrates with different crystalline phases and morphologies by a large excess of silver (I) cations led to the formation of 1-D nanostructured novel Ag-Mo-O ternary phase in what may be the simplest experimental procedure available to date that has yielded a 1-D nanostructure, regardless the nature of the constituent material. Interaction of this novel ternary phase with pyrrole vapors at high reaction temperatures led to heterogeneous nanostructured composites that exhibited a silver nanorod core. Nanoscrolls of vanadium pentoxide xerogel were synthesized through a novel, facile reflux-based method that

  18. Infrared spectroscopy of pyrrole-2-carboxaldehyde and its dimer: A planar β-sheet peptide model?

    NASA Astrophysics Data System (ADS)

    Rice, Corey A.; Dauster, Ingo; Suhm, Martin A.

    2007-04-01

    Intermolecular interactions relevant for antiparallel β-sheet formation between peptide strands are studied by Fourier transform infrared spectroscopy of the low temperature, vacuum-isolated model compound pyrrole-2-carboxaldehyde and its dimer in the N-H and C O stretching range. Comparison to quantum chemical predictions shows that even for some triple-zeta quality basis sets, hybrid density functionals and Møller-Plesset perturbation calculations fail to provide a consistent and fully satisfactory description of hydrogen bond induced frequency shifts and intensity ratios in the double-harmonic approximation. The latter approach even shows problems in reproducing the planar structure of the dimer and the correct sign of the C O stretching shift for standard basis sets. The effect of matrix isolation is modeled by condensing layers of Ar atoms on the isolated monomer and dimer. The dimer structure is discussed in the context of the peptide β-sheet motif.

  19. Infrared spectroscopy of pyrrole-2-carboxaldehyde and its dimer: a planar beta-sheet peptide model?

    PubMed

    Rice, Corey A; Dauster, Ingo; Suhm, Martin A

    2007-04-01

    Intermolecular interactions relevant for antiparallel beta-sheet formation between peptide strands are studied by Fourier transform infrared spectroscopy of the low temperature, vacuum-isolated model compound pyrrole-2-carboxaldehyde and its dimer in the N-H and C=O stretching range. Comparison to quantum chemical predictions shows that even for some triple-zeta quality basis sets, hybrid density functionals and Møller-Plesset perturbation calculations fail to provide a consistent and fully satisfactory description of hydrogen bond induced frequency shifts and intensity ratios in the double-harmonic approximation. The latter approach even shows problems in reproducing the planar structure of the dimer and the correct sign of the C=O stretching shift for standard basis sets. The effect of matrix isolation is modeled by condensing layers of Ar atoms on the isolated monomer and dimer. The dimer structure is discussed in the context of the peptide beta-sheet motif. PMID:17430038

  20. One-Pot Aminoethylation of Indoles/Pyrroles with Alkynes and Sulfonyl Azides.

    PubMed

    Rajasekar, Shanmugam; Yadagiri, Dongari; Anbarasan, Pazhamalai

    2015-11-16

    A general and efficient one-pot aminoethylation of substituted indoles/pyrroles was accomplished for the synthesis of various tryptamine derivatives employing a combination of alkynes and sulfonyl azides as readily accessible aminoethylating agents. The reaction features a successful integration of copper-catalyzed alkyne and azide cycloaddition to N-sulfonyl-1,2,3-triazole, rhodium-catalyzed selective insertion of α-iminocarbenes onto the C3-H bond of indoles, and reduction of the resultant enamides to tryptamine derivatives employing either NaCNBH3 or palladium catalyst, in one-pot. The reaction also showed excellent functional-group tolerance and allowed the synthesis of various substituted tryptamines in good to excellent yield. This transformation constitutes a one-pot formal regioselective functionalization of terminal alkynes. Utility of the synthesized tryptamine was further demonstrated in the synthesis of dihydro-β-carboline and tryptoline. PMID:26443500

  1. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide

    PubMed Central

    Hargrove, Amanda E.; Martinez, Thomas F.; Hare, Alissa A.; Kurmis, Alexis A.; Phillips, John W.; Sud, Sudha; Pienta, Kenneth J; Dervan, Peter B.

    2015-01-01

    Pyrrole-imidazole (Py-Im) polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE)-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse xenograft model. In addition to the effects on AR regulated transcription, RNA-seq analysis revealed inhibition of topoisomerase-DNA binding as a potential mechanism that contributes to the antitumor effects of polyamides in cell culture and in xenografts. These studies support the therapeutic potential of Py-Im polyamides to target multiple aspects of transcriptional regulation in prostate cancers without genotoxic stress. PMID:26571387

  2. Supramolecular biosensors based on electropolymerised pyrrole-cyclodextrin modified surfaces for antibody detection.

    PubMed

    Wajs, Ewelina; Fernández, Núria; Fragoso, Alex

    2016-06-01

    The self-assembly of an adamantane-appended polymer bearing an antigen fragment on a polypyrrole-cyclodextrin modified surface provides a highly sensitive immunosensor with low limits of detection for celiac disease related targets. The pyrrole-carboxylic acid films were formed on the surface of gold electrodes by electropolymerisation and followed by covalent attachment of cyclodextrin units. Surface plasmon resonance measurements confirmed the role of the host/guest interactions between adamantane moieties and β-cyclodextrin hosts in the formation of the supramolecular sensor interface. Furthermore, this novel electrochemical supramolecular platform was effective in the amperometric detection of anti-gliadin antibodies in spiked serum samples with very good signal recovery. PMID:27097527

  3. Quantum chemical studies of the pyrrole-water and pyridine-water complexes

    NASA Astrophysics Data System (ADS)

    Martoprawiro, Muhamad A.; Bacskay, George B.

    An ab initio quantum chemical study of the hydrogen bonded binary complexes pyrrole-water and pyridine-water is reported. The calculations were performed largely at the MP2 level of theory using basis sets of double-zeta-plus polarization functions quality and focus on properties of the complexes such as molecular geometries, energies, harmonic vibrational frequencies, dipole moments and 14N nuclear quadrupole coupling constants. Where possible, the results of the calculations are compared with experimental data. In addition, the interaction potentials are studied in some detail, specifically with regard to basis set superposition and its effect on geometries, intermolecular vibrational frequencies and binding energies. The nature of interaction, i.e., the importance of electrostatic, Pauli repulsion, polarization, charge transfer and dispersion contributions to the hydrogen bond energies, as obtained in constrained spatial orbital variation analyses, is also discussed.

  4. Oxygen Reduction Reaction on Cobalt--(6)Pyrrole Cluster: Density Functional Theory Study

    NASA Astrophysics Data System (ADS)

    Saputro, Adhitya G.; Rusydi, Febdian; Kasai, Hideaki; Dipojono, Hermawan K.

    2012-03-01

    We investigate the potential energy surface profile for various water formation reaction schemes on an unsupported cobalt--(6)pyrrole [Co--(6)Ppy] cluster in the vacuum state by density functional theory (DFT) calculations. We find that in the Co--(6)Ppy cluster, the formation of H2O2 is energetically not favorable. Instead of forming H2O2ad, the \\text{HO\\text{2ad} + H reaction forms 2OHad or \\text{O\\text{ad} + H2O immediately. The adsorption of H2O2 on the Co--(6)Ppy cluster is possible only if the H2O2 molecule comes from or forms outside of the cluster. The formation of two OH molecules instead of H2O2 on the Co--(6)Ppy cluster suggests that the oxygen reduction reaction (ORR) mechanism on the unsupported Co--(6)Ppy cluster in the vacuum state prefers the direct four-electron reduction to water.

  5. Catalytic formal [2+2+1] synthesis of pyrroles from alkynes and diazenes via TiII/TiIV redox catalysis

    NASA Astrophysics Data System (ADS)

    Gilbert, Zachary W.; Hue, Ryan J.; Tonks, Ian A.

    2016-01-01

    Pyrroles are structurally important heterocycles. However, the synthesis of polysubstituted pyrroles is often challenging. Here, we report a multicomponent, Ti-catalysed formal [2+2+1] reaction of alkynes and diazenes for the oxidative synthesis of penta- and trisubstituted pyrroles: a nitrenoid analogue to classical Pauson-Khand-type syntheses of cyclopentenones. Given the scarcity of early transition-metal redox catalysis, preliminary mechanistic studies are presented. Initial stoichiometric and kinetic studies indicate that the mechanism of this reaction proceeds through a formally TiII/TiIV redox catalytic cycle, in which an azatitanacyclobutene intermediate, resulting from [2+2] alkyne + Ti imido coupling, undergoes a second alkyne insertion followed by reductive elimination to yield pyrrole and a TiII species. The key component for catalytic turnover is the reoxidation of the TiII species to a TiIV imido via the disproportionation of an η2-diazene-TiII complex.

  6. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors.

    PubMed

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Xu, Xiao-Ying; Zhang, Xiao-Mei; Yuan, Wei-Cheng

    2016-01-01

    For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  7. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

    PubMed Central

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Zhang, Xiao-Mei

    2016-01-01

    Summary For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  8. Both visual and fluorescent sensors for Zn(2+) based on bis(pyrrol-2-yl-methyleneamine) platform.

    PubMed

    Wu, Wei-Na; Mao, Pan-Dong; Jia, Lei; Wang, Yuan; Xu, Zhou-Qing

    2016-09-01

    Two bis(pyrrol-2-yl-methyleneamine) chemo-sensors, 1, 3- and 1, 4-bis[3,4-dimethyl-5-ethyloxy -carbonyl-pyrrol-2-yl-methyleneamine]benzene (H2L(1) and H2L(2), respectively) have been synthesized and characterized, which exhibit high selectivity as off-on fluorescence sensors toward Zn(2+) in CH3CN/H2O (9:1, v/v) solution. The detection limits of both sensors are at the parts per million level. Moreover, the probes H2L(1) and H2L(2) could sense Zn(2+) by "naked eye" with a color change from colorless to yellow, and from yellow to dark yellow, respectively. To test the practical use of the probes, the determination of Zn(2+) in real water samples was also evaluated. PMID:27208758

  9. Ab initio multiple cloning simulations of pyrrole photodissociation: TKER spectra and velocity map imaging

    SciTech Connect

    Makhov, Dmitry V.; Saita, Kenichiro; Martinez, Todd J.; Shalashilin, Dmitrii V.

    2014-12-11

    In this study, we report a detailed computational simulation of the photodissociation of pyrrole using the ab initio Multiple Cloning (AIMC) method implemented within MOLPRO. The efficiency of the AIMC implementation, employing train basis sets, linear approximation for matrix elements, and Ehrenfest configuration cloning, allows us to accumulate significant statistics. We calculate and analyze the total kinetic energy release (TKER) spectrum and Velocity Map Imaging (VMI) of pyrrole and compare the results directly with experimental measurements. Both the TKER spectrum and the structure of the velocity map image (VMI) are well reproduced. Previously, it has been assumed that the isotropic component of the VMI arises from long time statistical dissociation. Instead, our simulations suggest that ultrafast dynamics contributes significantly to both low and high energy portions of the TKER spectrum.

  10. X-ray crystallography and computational studies of a variety of pyrrole derivatives obtained from mesoionic oxazoles and selected chromenones

    NASA Astrophysics Data System (ADS)

    Brancatelli, Giovanna; Bruno, Giuseppe; Nicolò, Francesco; Cordaro, Massimiliano; Grassi, Giovanni; Risitano, Francesco; Scala, Angela

    2011-03-01

    The molecular structure, packing properties, and intermolecular interactions of a series of pyrrole derivatives have been determined by single-crystal X-ray diffraction. They were efficiently synthesized from mesoionic oxazoles and selected chromenones via initial 1,3-dipolar cycloaddition followed by cascade transformations. Compounds 4- 6 are described as three fused rings associated in the crystal lattice through H-bonding interactions. Besides the H-bonding interactions encountered in the crystal packing of 4- 8, a different strong centrosymmetric π-interaction has been found in 8, involving the cyano group and the π-system of aromatic pyrrole ring. A density functional theory (DFT) study was carried out on the supramolecular dimer in order to understand the nature and role of this intermolecular force in driving the molecular packing.

  11. Highly enantioselective synthesis of beta-heteroaryl-substituted dihydrochalcones through Friedel-Crafts alkylation of indoles and pyrrole.

    PubMed

    Wang, Wentao; Liu, Xiaohua; Cao, Weidi; Wang, Jun; Lin, Lili; Feng, Xiaoming

    2010-02-01

    A highly enantioselective Friedel-Crafts (F-C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N'-dioxide-Sc(OTf)(3) complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85-92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading, which showed the potential value of the catalyst system. Meanwhile, a strong positive nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible working model is proposed to explain the origin of the activation and asymmetric induction. PMID:20013964

  12. Both visual and fluorescent sensors for Zn2 + based on bis(pyrrol-2-yl-methyleneamine) platform

    NASA Astrophysics Data System (ADS)

    Wu, Wei-Na; Mao, Pan-Dong; Jia, Lei; Wang, Yuan; Xu, Zhou-Qing

    2016-09-01

    Two bis(pyrrol-2-yl-methyleneamine) chemo-sensors, 1, 3- and 1, 4-bis[3,4-dimethyl-5-ethyloxy -carbonyl-pyrrol-2-yl-methyleneamine]benzene (H2L1 and H2L2, respectively) have been synthesized and characterized, which exhibit high selectivity as off-on fluorescence sensors toward Zn2 + in CH3CN/H2O (9:1, v/v) solution. The detection limits of both sensors are at the parts per million level. Moreover, the probes H2L1 and H2L2 could sense Zn2 + by "naked eye" with a color change from colorless to yellow, and from yellow to dark yellow, respectively. To test the practical use of the probes, the determination of Zn2 + in real water samples was also evaluated.

  13. 1H, 13C MAS NMR and GIAO-CPHF calculations of chloramphenicol, thiamphenicol and their pyrrole analogues

    NASA Astrophysics Data System (ADS)

    Żołek, Teresa; Paradowska, Katarzyna; Krajewska, Dorota; Różański, Andrzej; Wawer, Iwona

    2003-02-01

    The 13C CP MAS and 1H MAS NMR and ab initio (GIAO-CPHF) calculations were used to obtain structural information on two known antibiotics: chloramphenicol, and thiamphenicol, and two new analogues: DL- threo-1-(1-methyl-4-nitro-pyrrole-2-yl)-2-dichloroacetamidopropane-1,3-diol and DL- threo-1-(1-methylsulfonylpyrrole-3-yl)-2-dichloroacetamidopropane-1,3-diol.

  14. Direct detection of pyridine formation by the reaction of CH (CD) with pyrrole: a ring expansion reaction

    SciTech Connect

    Soorkia, Satchin; Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Trevitt, Adam J.; Wilson, Kevin R.; Leone, Stephen R.

    2010-03-16

    The reaction of the ground state methylidyne radical CH (X2Pi) with pyrrole (C4H5N) has been studied in a slow flow tube reactor using Multiplexed Photoionization Mass Spectrometry coupled to quasi-continuous tunable VUV synchrotron radiation at room temperature (295 K) and 90 oC (363 K), at 4 Torr (533 Pa). Laser photolysis of bromoform (CHBr3) at 248 nm (KrF excimer laser) is used to produce CH radicals that are free to react with pyrrole molecules in the gaseous mixture. A signal at m/z = 79 (C5H5N) is identified as the product of the reaction and resolved from 79Br atoms, and the result is consistent with CH addition to pyrrole followed by Helimination. The Photoionization Efficiency curve unambiguously identifies m/z = 79 as pyridine. With deuterated methylidyne radicals (CD), the product mass peak is shifted by +1 mass unit, consistent with the formation of C5H4DN and identified as deuterated pyridine (dpyridine). Within detection limits, there is no evidence that the addition intermediate complex undergoes hydrogen scrambling. The results are consistent with a reaction mechanism that proceeds via the direct CH (CD) cycloaddition or insertion into the five-member pyrrole ring, giving rise to ring expansion, followed by H atom elimination from the nitrogen atom in the intermediate to form the resonance stabilized pyridine (d-pyridine) molecule. Implications to interstellar chemistry and planetary atmospheres, in particular Titan, as well as in gas-phase combustion processes, are discussed.

  15. Copper-Catalyzed Coupling of 2-Siloxy-1-alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes.

    PubMed

    Tan, Wei Wen; Yoshikai, Naohiko

    2016-07-01

    We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes. PMID:27259097

  16. Mixed β-pyrrole substituted meso-tetraphenylporphyrins and their metal complexes: optical nonlinearity using degenerate four wave mixing technique.

    PubMed

    Kalnoor, Basanth S; Bisht, Prem B; Jena, Kailash C; Velkannan, V; Bhyrappa, P

    2013-08-29

    We have investigated the roles of structural modification and polar effects in the optical nonlinearities of a series of selectively mixed β-pyrrole functionalized tetraphenylporphyrin, MTPP(CHO)(R)2 (R = H, Br, 2-thienyl, phenyl (Ph), phenylethynyl (PE) compounds and their metal (Cu(II), Zn(II)) complexes in toluene. In the present study, we have used phase conjugation geometry of the four wave mixing process to measure the third order nonlinear susceptibility (χ(3)) and the second order hyperpolarizabilty ((γ)) with picosecond laser pulse excitation at 532 nm. An increase in the values of χ(3) and (γ) for electron-withdrawing groups was observed whereas an opposite trend was noticed for the electron-donating groups at the β-pyrrole positions. In the Cu(II) and Zn(II) complexes of substituted free base porphyrins, the distortion of the macrocyclic ring may be responsible for the reduction of the values of χ(3) and (γ). From fluorescence measurements, it has been found that the electron-donating and electron-withdrawing substituted groups at β-pyrrole positions and also the macrocyclic ring distortion of the porphyrin lead to increased radiationless transitions. PMID:23909768

  17. Calix[4]pyrrole derivative: recognition of fluoride and mercury ions and extracting properties of the receptor-based new material.

    PubMed

    de Namor, Angela F Danil; Khalife, Rasha

    2008-12-11

    A calix[4]pyrrole derivative, namely, meso-tetramethyl tetrakis (4-phenoxy methyl ketone) calix[4]pyrrole, 1, was synthesized and structurally (1H NMR) and thermodynamically characterized. The complexing properties of this receptor with a wide variety of anions and cations in dipolar aprotic media (acetonitrile, propylene carbonate, and dimethyl sulfoxide) were investigated through 1H NMR and conductance studies. The former technique was used to assess whether or not complexation occurs and if so to identify the active sites of interaction of 1 with ions. The composition of the complexes was established by conductance measurements. It was found that in dipolar aprotic solvents, 1 interacts only with two polluting ions (fluoride and mercury). The complexation thermodynamics of 1 and these ions in these solvents is reported. The medium effect on the binding process involving the fluoride ion is discussed taking into account the solvation properties of reactants and the product. Complexes of moderate stability are found. Given that this is an important factor to consider for the recycling of the loaded material in extraction processes, 1 was treated with formaldehyde in basic medium leading to the production of a calix[4]pyrrole based material able to extract fluoride and mercury (II) ions from water. Thus the optimum conditions for the extraction of these ions from aqueous solutions were established. The material is easily recyclable using an organic acid. Final conclusions are given. PMID:19053691

  18. Pyrrole Alkaloids with Potential Cancer Chemopreventive Activity Isolated from a Goji Berry-Contaminated Commercial Sample of African Mango

    PubMed Central

    2015-01-01

    Bioassay-guided fractionation of a commercial sample of African mango (Irvingia gabonensis) that was later shown to be contaminated with goji berry (Lycium sp.) led to the isolation of a new pyrrole alkaloid, methyl 2-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]propanoate, 1, along with seven known compounds, 2–8. The structures of the isolated compounds were established by analysis of their spectroscopic data. The new compound 1g showed hydroxyl radical-scavenging activity with an ED50 value of 16.7 μM, whereas 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (2) was active in both the hydroxyl radical-scavenging (ED50 11.9 μM) and quinone reductase-induction [CD (concentration required to double QR activity) 2.4 μM)] assays used. The isolated compounds were shown to be absent in a taxonomically authenticated African mango sample but present in three separate authentic samples of goji berry (Lycium barbarum) using LC-MS and 1H NMR fingerprinting analysis, including one sample that previously showed inhibitory activity in vivo in a rat esophageal cancer model induced with N-nitrosomethylbenzylamine. Additionally, microscopic features characteristic of goji berry were observed in the commercial African mango sample. PMID:24792835

  19. Identification of the altered pyrrole in the isomeric sulfmyoglobins: hyperfine shift patterns as indicators of ring saturation in ferric chlorins

    SciTech Connect

    Chatfield, M.J.; La Mar, G.N.; Smith, K.M.; Leung, H.K.; Pandey, R.K.

    1988-03-08

    Analysis of the /sup 1/H NMR hyperfine shift patterns of isomeric sulfmyoglobins is carried out in the met-aquo and met-cyano states to determine the site of saturation in each protein. The utility of the patterns for structure elucidation is established by specific deuterium labeling of heme methyls of the terminal base product. On the basis of the know saturation of ring B in this isomer. The methyl resonance of the saturated ring is found to have strongly attenuated contact shift. Thus, the heme methyl contact shift pattern is diagnostic for the saturated pyrrole in the high-spin state. This rationale is then applied to analyze the assigned NMR spectra of the initial and terminal acid sulfmyoglobin products, revealing that the same ring B is saturated in each isomer. In contrast, the heme methyl contact shift pattern in low-spin ferric complexes reveals that the methyls both on the affected pyrrole and on the trans pyrrole are influenced similarly on sulfmyoglobin formation, precluding the use of this methyl shift pattern as a unique indicator of the site of saturation. Identification of exchangeable proximal histidine resonances for met-aquo sulfmyoglobin complexes with shifts similar to that in native myoglobin dictates inconsequential axial alterations in the sulfmyoglobins, while location of downfield meso proton resonances analogous to those of the native protein demonstrates the retention of the coordinate water in the active site of met-sulfmyoglobin.

  20. Designing anthraquinone-pyrrole redox intercalating probes for electrochemical gene detection.

    PubMed

    Lin, Yu-Jen; Wu, Yung-Chao; Mani, Veerappan; Huang, Sheng-Tung; Huang, Chih-Hung; Hu, Yi-Chiuen; Peter Shan, His-Chi

    2016-05-15

    The real-time quantitative electrochemical monitoring of nucleic acid amplification through PCR is a promising renowned methodology to detect pathogenic DNAs. In this work, anthraquinone-pyrrole derivatives based redox intercalating probes (AP probes: AP1, AP2) have been designed, synthesized, characterized and successfully demonstrated in real-time like quantitative PCR. The rationally designed AP probes exhibited excellent DNA binding abilities and electrochemical behaviors. The binding parameters such as binding constant, binding site size and diffusion coefficient were estimated which were comparable to literature reports. Besides, the AP probes are highly stable under PCR thermal conditions and did not inhibit PCR. Therefore, a real-time like quantification of DNA amplification was demonstrated to quantify the initial copy number of target genes. The probe AP2 has excellent ability to detect ~10(3) copies of target tpc DNA with good sensitivity. The AP probes are metal-free, easily synthesizable, non-toxic, thermally stable and feasible for miniaturized PCR chips. PMID:26716423

  1. A concise synthesis of (+)-batzelladine B from simple pyrrole-based starting materials

    NASA Astrophysics Data System (ADS)

    Parr, Brendan T.; Economou, Christos; Herzon, Seth B.

    2015-09-01

    Alkaloids, secondary metabolites that contain basic nitrogen atoms, are some of the most well-known biologically active natural products in chemistry and medicine. Although efficient laboratory synthesis of alkaloids would enable the study and optimization of their biological properties, their preparation is often complicated by the basicity and nucleophilicity of nitrogen, its susceptibility to oxidation, and its ability to alter reaction outcomes in unexpected ways--for example, through stereochemical instability and neighbouring group participation. Efforts to address these issues have led to the invention of a large number of protecting groups that temper the reactivity of nitrogen; however, the use of protecting groups typically introduces additional steps and obstacles into the synthetic route. Alternatively, the use of aromatic nitrogen heterocycles as synthetic precursors can attenuate the reactivity of nitrogen and streamline synthetic strategies. Here we use such an approach to achieve a synthesis of the complex anti-HIV alkaloid (+)-batzelladine B in nine steps (longest linear sequence) from simple pyrrole-based starting materials. The route uses several key transformations that would be challenging or impossible to implement using saturated nitrogen heterocycles and highlights some of the advantages of beginning with aromatic reagents.

  2. Flexible electrochemical capacitors based on polypyrrole/carbon fibers via chemical polymerization of pyrrole vapor

    NASA Astrophysics Data System (ADS)

    Yuan, Wei; Han, Gaoyi; Xiao, Yaoming; Chang, Yunzhen; Liu, Cuixian; Li, Miaoyu; Li, Yanping; Zhang, Ying

    2016-07-01

    Polypyrrole (PPy) has been deposited on the carbon fibers (CFs) via chemical oxidation of monomer vapor strategy, during which FeCl3·6H2O in acetonitrile adsorbed on CFs acts as oxidant to polymerize the pyrrole vapor. The morphologies and capacitive properties of the PPy deposited on CFs (PPy/CFs) are strongly influenced by the concentration of oxidant used in the process. The assembled flexible capacitors by using PPy/CFs as electrodes and LiCl/polyvinyl alcohol as gel electrolyte have been evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show that the composites of PPy/CFs prepared by using 350 mg mL-1 FeCl3·6H2O as oxidant (PPy/CFs-350) exhibit relatively higher specific capacitance and good rate capability. Compared with PPy/CFs prepared by electrochemical deposition (retaining 5% of the initial capacitance), the PPy/CFs prepared by chemically polymerizing monomer vapor shows excellent stability (retaining 85% of initial capacitance after 5000 cycles). Furthermore, cells fabricated by PPy/CFs show a fairly good performance under various bending states, three cells of PPy/CFs-350 connected in series can light up a light emitting diode with a voltage threshold of about 2.5 V for approximate 10 min after being charged for about 3 min, revealing the potential of the cells' practical applications.

  3. Animal Toxicity of Hairpin Pyrrole-Imidazole Polyamides Varies with the Turn Unit

    PubMed Central

    2013-01-01

    A hairpin pyrrole-imidazole polyamide (1) targeted to the androgen receptor consensus half-site was found to exert antitumor effects against prostate cancer xenografts. A previous animal study showed that 1, which has a chiral amine at the α-position of the γ-aminobutyric acid turn (γ-turn), did not exhibit toxicity at doses less than 10 mg/kg. In the same study, a polyamide with an acetamide at the β-position of the γ-turn resulted in animal morbidity at 2.3 mg/kg. To identify structural motifs that cause animal toxicity, we synthesized polyamides 1–4 with variations at the α- and β-positions in the γ-turn. Weight loss, histopathology, and serum chemistry were analyzed in mice post-treatment. While serum concentration was similar for all four polyamides after injection, dose-limiting liver toxicity was only observed for three polyamides. Polyamide 3, with an α-acetamide, caused no significant evidence of rodent toxicity and retains activity against LNCaP xenografts. PMID:24015881

  4. Ground and excited state vibrations of 2-(2‧-pyridyl)pyrrole

    NASA Astrophysics Data System (ADS)

    Kijak, Michał; Nosenko, Yevgeniy; Singh, Ajay; Thummel, Randolph P.; Brutschy, Bernhard; Waluk, Jacek

    2007-11-01

    2-(2'-pyridyl)pyrrole (PP), a molecule with a weak intramolecular hydrogen bond, reveals excited state intramolecular proton transfer (ESIPT). The photoreaction occurs even for a cold molecule isolated in a supersonic jet. Under such conditions, the ESIPT rate can be enhanced or suppressed by excitation of specific S 1 vibronic levels. Investigations of vibrational structure of PP in S 0 and S 1 states were carried out using FTIR spectroscopy of solutions and matrix-isolated samples, combined with laser induced fluorescence (LIF) excitation, hole-burning, and dispersed fluorescence measurements in supersonic jets. The theoretical analysis included calculations of ground and excited state vibrational patterns. Detailed assignments were proposed for most of the ground state vibrational transitions and for the S 1 modes observed in the LIF and hole-burning spectra. The results show clearly that the phototautomerization is promoted by in-plane vibrations which can increase the strength of the intramolecular hydrogen bond. On the contrary, excitation of out-of-plane vibrations, which weakens the hydrogen bond, leads to a dramatic decrease in the proton transfer rate.

  5. Novel Pt(II) complexes containing pyrrole oxime; synthesis, characterization and DNA binding studies

    NASA Astrophysics Data System (ADS)

    Erdogan, Deniz Altunoz; Özalp-Yaman, Şeniz

    2014-05-01

    Since the discovery of anticancer activity and subsequent clinical success of cisplatin (cis-[PtCl2(NH3)2]), platinum-based compounds have since been widely synthesized and studied as potential chemotherapeutic agents. In this sense, three novel nuclease active Pt(II) complexes with general formula; [Pt(NH3)Cl(L)] (1), [Pt(L)2] (2), and K[PtCl2(L)] (3) in which L is 1-H-pyrrole-2-carbaldehyde oxime were synthesized. Characterization of complexes was performed by elemental analysis, FT-IR, 1H NMR and mass spectroscopy measurements. Interaction of complexes (1-3) with calf thymus deoxyribonucleic acid (ct-DNA) was investigated by using electrochemical, spectroelectrochemical methods and cleavage studies. The hyperchromic change in the electronic absorption spectrum of the Pt(II) complexes indicates an electrostatic interaction between the complexes and ct-DNA. Binding constant values between 4.42 × 103 and 5.09 × 103 M-1 and binding side size values between 2 and 3 base pairs were determined from cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies.

  6. The 8-Pyrrole-Benzothiazinones Are Noncovalent Inhibitors of DprE1 from Mycobacterium tuberculosis.

    PubMed

    Makarov, Vadim; Neres, João; Hartkoorn, Ruben C; Ryabova, Olga B; Kazakova, Elena; Šarkan, Michal; Huszár, Stanislav; Piton, Jérémie; Kolly, Gaëlle S; Vocat, Anthony; Conroy, Trent M; Mikušová, Katarína; Cole, Stewart T

    2015-08-01

    8-Nitro-benzothiazinones (BTZs), such as BTZ043 and PBTZ169, inhibit decaprenylphosphoryl-β-d-ribose 2'-oxidase (DprE1) and display nanomolar bactericidal activity against Mycobacterium tuberculosis in vitro. Structure-activity relationship (SAR) studies revealed the 8-nitro group of the BTZ scaffold to be crucial for the mechanism of action, which involves formation of a semimercaptal bond with Cys387 in the active site of DprE1. To date, substitution of the 8-nitro group has led to extensive loss of antimycobacterial activity. Here, we report the synthesis and characterization of the pyrrole-benzothiazinones PyrBTZ01 and PyrBTZ02, non-nitro-benzothiazinones that retain significant antimycobacterial activity, with MICs of 0.16 μg/ml against M. tuberculosis. These compounds inhibit DprE1 with 50% inhibitory concentration (IC50) values of <8 μM and present favorable in vitro absorption-distribution-metabolism-excretion/toxicity (ADME/T) and in vivo pharmacokinetic profiles. The most promising compound, PyrBTZ01, did not show efficacy in a mouse model of acute tuberculosis, suggesting that BTZ-mediated killing through DprE1 inhibition requires a combination of both covalent bond formation and compound potency. PMID:25987616

  7. The 8-Pyrrole-Benzothiazinones Are Noncovalent Inhibitors of DprE1 from Mycobacterium tuberculosis

    PubMed Central

    Makarov, Vadim; Neres, João; Hartkoorn, Ruben C.; Ryabova, Olga B.; Kazakova, Elena; Šarkan, Michal; Huszár, Stanislav; Piton, Jérémie; Kolly, Gaëlle S.; Vocat, Anthony; Conroy, Trent M.; Mikušová, Katarína

    2015-01-01

    8-Nitro-benzothiazinones (BTZs), such as BTZ043 and PBTZ169, inhibit decaprenylphosphoryl-β-d-ribose 2′-oxidase (DprE1) and display nanomolar bactericidal activity against Mycobacterium tuberculosis in vitro. Structure-activity relationship (SAR) studies revealed the 8-nitro group of the BTZ scaffold to be crucial for the mechanism of action, which involves formation of a semimercaptal bond with Cys387 in the active site of DprE1. To date, substitution of the 8-nitro group has led to extensive loss of antimycobacterial activity. Here, we report the synthesis and characterization of the pyrrole-benzothiazinones PyrBTZ01 and PyrBTZ02, non-nitro-benzothiazinones that retain significant antimycobacterial activity, with MICs of 0.16 μg/ml against M. tuberculosis. These compounds inhibit DprE1 with 50% inhibitory concentration (IC50) values of <8 μM and present favorable in vitro absorption-distribution-metabolism-excretion/toxicity (ADME/T) and in vivo pharmacokinetic profiles. The most promising compound, PyrBTZ01, did not show efficacy in a mouse model of acute tuberculosis, suggesting that BTZ-mediated killing through DprE1 inhibition requires a combination of both covalent bond formation and compound potency. PMID:25987616

  8. A concise synthesis of (+)-batzelladine B from simple pyrrole-based starting materials

    PubMed Central

    Parr, Brendan T.; Economou, Christos; Herzon, Seth B.

    2015-01-01

    Alkaloids, secondary metabolites that contain basic nitrogen atoms, are some of the most well-known biologically active natural products in chemistry and medicine1. Although the efficient laboratory syntheses of alkaloids would enable researchers to study and optimize their biological properties,2 the basicity and nucleophilicity of nitrogen, its susceptibility to oxidation, and its ability to alter reaction outcomes in unexpected ways – for example, through stereochemical instability and neighboring group participation – complicates their preparation in the laboratory. Efforts to address these issues have led to the invention of a large number of protecting groups that temper the reactivity of nitrogen3; however, the use of protecting groups typically introduce additional steps and obstacles into the synthetic route. Alternatively, the use of aromatic nitrogen heterocycles as synthetic precursors can attenuate the reactivity of nitrogen and streamline synthetic strategies4. In this manuscript, we use such an approach to achieve a synthesis of the complex anti-HIV alkaloid (+)-batzelladine B in nine steps (longest-linear sequence) from simple pyrrole-based starting materials. The route employs several key transformations that would be challenging or impossible to implement using saturated nitrogen heterocycles and highlights some of the advantages conferred by the use of aromatic starting materials. PMID:26375010

  9. Fabrication and electrical characterization of pyrrole-aniline copolymer-based Schottky diodes

    NASA Astrophysics Data System (ADS)

    Sönmezoğlu, S.; Durmuş, C. B.; Taş, R.; Çankaya, G.; Can, M.

    2011-05-01

    In this work, pyrrole-aniline copolymer/p-Si structure has been fabricated by forming a thin organic copolymer film on a p-Si wafer. A good rectifying behavior was seen from the current-voltage (I-V) characteristics. The characteristic parameters of the structure such as barrier height, ideality factor, interface states density and series resistance were determined from the electrical measurements using I-V, Cheung's, and modified Norde's function. The calculated barrier height values from different methods have shown the consistency of the approaches. The obtained ideality factor which is greater than unity refers to the deviation from ideal diode characteristics. This deviation can be attributed to secondary mechanisms, which include interface dipoles due to interface doping or specific interface structure, as well as fabrication-induced defects at the interface. The energy distribution of interface-state density of the copolymer-based structure was determined, and the interface-state density was found to vary from 1.27 × 1016 cm-2 eV-1 in (0.07 - Ev) eV to 2.45 × 1015 cm-2 eV-1 in (0.52 - Ev) eV. Furthermore, these copolymers were characterized with UV-vis, FTIR techniques, and thermal analysis.

  10. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation

    PubMed Central

    Janssen, Brian M. G.; van Ommeren, Sven P. F. I.; Merkx, Maarten

    2015-01-01

    The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py–Im) polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py–Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py–Im polyamides. The effect of Py–Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR). Although the synthesis of different protein-Py–Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py–Im-polyamide conjugates. The practical use of protein-Py–Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established. PMID:26053396

  11. Monocrotaline pyrrole-induced endothelial cell megalocytosis involves a Golgi blockade mechanism.

    PubMed

    Shah, Mehul; Patel, Kirit; Sehgal, Pravin B

    2005-04-01

    Pyrrolizidine alkaloids initiate disease in the lung (pulmonary hypertension), liver (veno-occlusive disease and cirrhosis), and kidneys (afferent arteriolar block and mesangiolysis) by inducing a megalocytotic phenotype in target endothelial and parenchymal cells. A "hit-and-run" type of exposure to the bioactive pyrrolizidine results, within 2-3 days, in enlarged cells with large nuclei and enlarged Golgi and endoplasmic reticulum, while the cells remain in G2/M block. In the present study, we recapitulated monocrotaline pyrrole (MCTP)-induced megalocytosis in cultures of bovine pulmonary arterial endothelial cells (PAEC), human Hep3B hepatocytes, human type II-like alveolar epithelial cells (A549), and human pulmonary arterial smooth muscle cells (PASMC) and investigated the subcellular mechanism involved. There was an inverse relationship between reduction in caveolin (Cav)-1 levels and stimulation of promitogenic STAT3 and ERK1/2 cell signaling. In megalocytotic PAEC, the Golgi scaffolding protein GM130 was shifted from membranes with heavy density to those with a lighter density. This lighter Golgi fraction was enriched for hypo-oligomeric Cav-1, indicating dysfunctional trafficking of cargo. Immunofluorescence imaging studies confirmed the trapping of Cav-1 in a GM130-positive Golgi compartment. There was an increase in Ser25 phosphorylation of GM130 (typically a prelude to Golgi fragmentation and mitosis) and increased association between pGM130, cdc2 kinase, and Cav-1. Nevertheless, megalocytotic MCTP-treated cells showed reduced entry into mitosis upon stimulation with 2-methoxyestradiol (2-ME), reduced 2-ME-induced Golgi fragmentation, and a slowing of Golgi reassembly after nocodazole-induced fragmentation. These data suggest that a disruption of the trafficking and mitosis sensor functions of the Golgi may represent the subcellular mechanism leading to MCTP-induced megalocytosis ("the Golgi blockade hypothesis"). PMID:15561761

  12. Excess L-arginine restores endothelium-dependent relaxation impaired by monocrotaline pyrrole

    SciTech Connect

    Cheng Wei; Oike, Masahiro . E-mail: moike@pharmaco.med.kyushu-u.ac.jp; Hirakawa, Masakazu; Ohnaka, Keizo; Koyama, Tetsuya; Ito, Yushi

    2005-09-15

    The pyrrolizidine alkaloid plant toxin monocrotaline pyrrole (MCTP) causes pulmonary hypertension in experimental animals. The present study aimed to examine the effects of MCTP on the endothelium-dependent relaxation. We constructed an in vitro disease model of pulmonary hypertension by overlaying MCTP-treated bovine pulmonary artery endothelial cells (CPAEs) onto pulmonary artery smooth muscle cell-embedded collagen gel lattice. Acetylcholine (Ach) induced a relaxation of the control CPAEs-overlaid gels that were pre-contracted with noradrenaline, and the relaxation was inhibited by L-NAME, an inhibitor of NO synthase (NOS). In contrast, when MCTP-treated CPAEs were overlaid, the pre-contracted gels did not show a relaxation in response to Ach in the presence of 0.5 mM L-arginine. Expression of endothelial NOS protein, Ach-induced Ca{sup 2+} transients and cellular uptake of L-[{sup 3}H]arginine were significantly smaller in MCTP-treated CPAEs than in control cells, indicating that these changes were responsible for the impaired NO production in MCTP-treated CPAEs. Since cellular uptake of L-[{sup 3}H]arginine linearly increased according to its extracellular concentration, we hypothesized that the excess concentration of extracellular L-arginine might restore NO production in MCTP-treated CPAEs. As expected, in the presence of 10 mM L-arginine, Ach showed a relaxation of the MCTP-treated CPAEs-overlaid gels. These results indicate that the impaired NO production in damaged endothelial cells can be reversed by supplying excess L-arginine.

  13. Synthesis, spectral and chemical reactivity analysis of 2,4-dinitrophenyl hydrazone having pyrrole moiety

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-10-01

    In this paper we present combined experimental and theoretical study on a newly synthesized ethyl 2-cyano-3-[5-(2,4-dinitrophenyl)-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate (ECDHPA). Quantum chemical calculations have been performed using HF/6-31G(d,p), B3LYP/6-31G(d,p) and B3LYP/6-31++G(d,p) levels. The results obtained from quantum chemical calculations matches well with the experimental finding. Molecular electrostatic potential (MEP) surface of N17sbnd H39⋯O42dbnd N37 zone show green color having moderate electrostatic potential indicating hydrogen bonding. For the interactions N17sbnd H34⋯O42 electron density and its Laplacian (∇2ρBCP) are in the range 0.051-0.119 a.u., indicating interaction follows the Koch and Popelier criteria. The observed Nsbnd H (νN17sbnd H34) stretch of sbnd CHdbnd Nsbnd NH sbnd part of molecule at 3262 cm-1 indicate the red shift and the involvement in hydrogen bonding. Natural bond orbital (NBO) investigation shows various intramolecular interactions within molecule. Electrophilic charge transfer (ECT) has been calculated to investigate the relative electrophilic or nucleophilic behavior of reactant molecules involved in chemical reaction. The first hyperpolarizability (β0) value of ECDHPA is calculated as 22.42 × 10-30 esu. The solvent-induced effects on the non-linear optical properties (NLO) were studied using self-consistent reaction field (SCRF) method and observed that the β0 value increases as solvent polarity increases. DFT based electronic descriptors analysis reveals that studied molecule is a strong electrophile and it would undergo to form various heterocyclic compounds.

  14. Nerve cells culture from lumbar spinal cord on surfaces modified by plasma pyrrole polymerization.

    PubMed

    Zuñiga-Aguilar, E; Olayo, R; Ramírez-Fernández, O; Morales, J; Godínez, R

    2014-01-01

    Currently, there are several techniques for modified cell culture surfaces under research to improve cell growth and adhesion. Recently, different methods have been used for surface coating, using biomolecules that enhance cell attachment and growth of nerve cells from spinal cord, such as the use of Poly-DL-Ornithine/Laminin. Plasma-polymerized pyrrole (PPy)-treated surfaces have showed improvement on surfaces biocompatibility with the cells in culture since they do not interfere with any of the biological cell functions. In the present work, we present a novel mouse nerve cell culture technique, using PPy-treated cell culture surfaces. A comparative study of cell survival using Poly-DL-Ornithine/Laminin-treated surfaces was performed. Our results of cell survival when compared with data already reported by other investigators, show that cells cultured on the PPy-modified surface increased survival up to 21 days when compared with Poly-DL-Ornithine/Laminin-coated culture, where 8 days cell survival was obtained. There were electrical and morphological differences in the nerve cells grown in the different surfaces. By comparing the peak ion currents of Poly-DL-Ornithine/Laminin-seeded cells for 8 days with cells grown for 21 days on PPy, an increase of 516% in the Na(+) current and 127% in K(+) currents in cells seeded on PPy were observed. Immunofluorescence techniques showed the presence of cell synapses and culture viability after 21 days. Our results then showed that PPy-modified surfaces are an alternative culture method that increases nerve cells survival from lumbar spinal cord cell culture by preserving its electrical and morphological features. PMID:24650203

  15. Reaction of cationic transition metal complexes with furan, thiophene, and pyrrole. Model studies relevant to hydrodeoxygenation, hydrodesulfurization, and hydrodenitrogenation

    SciTech Connect

    Bakhtiar, R.; Jacobson, D.B.

    1995-12-01

    Hydrodesulfurization, denitrogenation, and deoxygenation reactions are important reactions in many research areas such as the removal of nitrogen and sulfur from coal. In this report, reactions of Fe{sup +} and FeL{sup +} (L = O, C{sub 4}H{sub 6}, c-C{sub 5}H{sub 6}, c-C{sub 5}H{sub 6}, C{sub 6}H{sub 6}, C{sub 5}H{sub 4}(=CH{sub 2})) with thiophene, furan, and pyrrole in the gas phase by using Fourier transform mass spectrometry (FTMS) are described. Fe{sup +}, Fe(C{sub 5}H{sub 5}){sup +}, and FeC{sub 6}H{sub 6}{sup +} yield exclusive, rapid adduct formation with thiophene, furan, and pyrrole. The iron-diene complex FeC{sub 4}H{sub 6}{sup +}, Fe(c-C{sub 5}H{sub 6}){sup +}), as well as FeC{sub 5}H{sub 4}(=CH{sub 2}){sup +} and FeO{sup +} are quite reactive. An intriguing reaction is the predominant, direct extrusion of CO from furan by FeC{sub 4}H{sub 6}{sup +}, Fe(c-C{sub 5}H{sub 6}){sup +}, Fe(C{sub 5}H{sub 4}(=CH{sub 2}){sup +}. In addition, FeC{sub 4}H{sub 6}{sup +} and Fe(c-C{sub 5}H{sub 6}){sup +} yield minor amounts of HCN extrusion from pyrrole. The absence of CS extrusion from thiophene may be due to the higher energy requirements than that for CO extrusion from furan or HCN extrusion from pyrrole. The dominant reaction channel for reaction of Fe(c-C{sub 5}H{sub 6}){sup +} with pyrrole and thiophene is hydrogen atom displacement which implies D{sup 0}(Fe(C{sub 5}H{sub 5}){sup +}-C{sub 4}H{sub 4}X) > D{sup 0}(Fe(C{sub 5}H{sub 5}){sup +}-H) = 46 {+-} 5 kcal/mol. D{sup 0}(Fe{sup +}-C{sub 4}H{sub 4}S) and D{sup 0}(Fe{sup +}C{sub 4}H{sub 5}N) = D{sup 0}(Fe{sup +}-C{sub 4}H{sub 6}) = 48 {+-} 5 kcal/mol. Finally, D{sup 0}(Fe{sup +}-C{sub 4}H{sub 4}O) > D{sup 0}(Fe{sup +}-C{sub 2}H{sub 4}) = 39.9 {+-} 1.4 kcal/mol and D{sup 0}(Fe{sup +}-C{sub 4}H{sub 4}O) < D{sup 0}(Fe{sup +}-C{sub 6}H{sub 6}) = 55 {+-} 5 kcal/mol. FeO{sup +} reacts rapidly with thiophene, furan, and pyrrole to yield initial loss of CO followed by additional neutral losses.

  16. Antimicrobial activity, structural evaluation and vibrational (FT-IR and FT-Raman) study of pyrrole containing vinyl derivatives.

    PubMed

    Singh, R N; Rawat, Poonam; Sahu, Sangeeta; Kumar, Yashvinder

    2016-02-01

    In this paper we present structural and vibrational study of three vinylpyrrole derivatives: 2-Cyano-3-(1H-pyrrol-2-yl)-acrylamide (CPA), 1-(1H-Pyrrol-2-yl)-Pent-1-en-3-one (PP) and 1-(1H-Pyrrol-2-yl)-but-1-en-3-one (PB), using ab initio, DFT and experimental approaches. The quantum chemical calculation have been performed on B3LYP method and 6-311+G(d,p) basis set. The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. The experimental FT-IR and Raman study clearly indicate that the compound exist as dimer in solid state. The binding energies of (CPA), (PP) and (PB) dimers are found to be 20.95, 18.75 and 19.18 kcal/mol, respectively. The vibrational analysis shows red shifts in v(N-H) and v(C=O) stretching as result of dimer formation. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using NBO analysis. Topological and energetic parameters reveal the nature of interactions in dimer. The local electronic descriptors analyses were used to predict the reactive sites in the molecule. Calculated first static hyperpolarizability of CPA, PP and PB is found to be 10.41×10(-30), 18.93×10(-30), 18.29×10(-30) esu, respectively, shows that investigated molecules will have non-linear optical response and might be used as non-linear optical (NLO) material. These vinylpyrrole compounds (CPA), (PP) and (PB) showed antifungal and antibacterial activity against Aspergillus niger and gram-positive bacteria Bacillus subtili. PMID:26513227

  17. Antimicrobial activity, structural evaluation and vibrational (FT-IR and FT-Raman) study of pyrrole containing vinyl derivatives

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam; Sahu, Sangeeta; Kumar, Yashvinder

    2016-02-01

    In this paper we present structural and vibrational study of three vinylpyrrole derivatives: 2-Cyano-3-(1H-pyrrol-2-yl)-acrylamide (CPA), 1-(1H-Pyrrol-2-yl)-Pent-1-en-3-one (PP) and 1-(1H-Pyrrol-2-yl)-but-1-en-3-one (PB), using ab initio, DFT and experimental approaches. The quantum chemical calculation have been performed on B3LYP method and 6-311 + G(d,p) basis set. The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. The experimental FT-IR and Raman study clearly indicate that the compound exist as dimer in solid state. The binding energies of (CPA), (PP) and (PB) dimers are found to be 20.95, 18.75 and 19.18 kcal/mol, respectively. The vibrational analysis shows red shifts in vN-H and vCdbnd O stretching as result of dimer formation. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using NBO analysis. Topological and energetic parameters reveal the nature of interactions in dimer. The local electronic descriptors analyses were used to predict the reactive sites in the molecule. Calculated first static hyperpolarizability of CPA, PP and PB is found to be 10.41 × 10- 30, 18.93 × 10- 30, 18.29 × 10- 30 esu, respectively, shows that investigated molecules will have non-linear optical response and might be used as non-linear optical (NLO) material. These vinylpyrrole compounds (CPA), (PP) and (PB) showed antifungal and antibacterial activity against Aspergillus niger and gram-positive bacteria Bacillus subtili.

  18. Eco-friendly synthesis, spectral and computational study of pyrrole-2-carboxaldehyde salicylhydrazone (PCSH) for its application

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-11-01

    In this paper we present eco-friendly synthesis of Pyrrole-2-carboxaldehyde salicylhydrazone (PCSH) and its molecular structural elucidation, spectral analysis and reactivity evaluation. Pyrrole-2-carboxaldehyde and salicyl hydrazide in water undergo condensation reaction to produce PCSH in good yield (88%). All results of quantum chemical calculation corroborate well with the experimental findings. The PCSH has been characterized by elemental analysis, FT-IR, 1H NMR, UV-Visible, and ESI-Mass spectroscopy. Density functional theory (DFT) calculations have been carried out for PCSH by performing B3LYP functional using the standard basis set 6-31 + g (d, p), and additional basis sets 6D and 10F. Two most stable conformers for PCSH have been observed around the dihedral angle N1C5C6N7. The red shift observed in O-H stretching vibration in the FT-IR spectrum indicates the presence of intramolecular hydrogen bonding. The rotational barrier between syn-syn (closed) syn-syn (open) found to be 2966.9 kcal/mol. The presence of hydroxyl proton at 10.45 ppm downfield in experimental 1H NMR spectrum confirms the existence of intramolecular hydrogen bonding in PCSH. Further, topological parameters analysis at the bond critical points using 'Atoms in molecules' theory reveals intramolecular hydrogen bonding. The energy of homonuclear intramolecular hydrogen bond (O17-H28⋯O10) is calculated to be 14.03 kcal/mol. The ellipticity results confirm the resonance assisted nature of this intramolecular hydrogen bond. In addition to this work, the reactive sites in PCSH have been explored using DFT descriptors, predicting nucleophilic reactions at carbonyl carbon and electrophilic reactions are possible at pyrrolic NH, amidic NH and double bond Cdbnd N leading to several heterocyclic products and metal complexes.

  19. Macrocyclic Transformations from Norrole to Isonorrole and an N-Confused Corrole with a Fused Hexacyclic Ring System Triggered by a Pyrrole Substituent.

    PubMed

    Li, Miao; Wei, Pingchun; Ishida, Masatoshi; Li, Xin; Savage, Mathew; Guo, Rui; Ou, Zhongping; Yang, Sihai; Furuta, Hiroyuki; Xie, Yongshu

    2016-02-01

    Three kinds of fused porphyrinoids, L2-L4, possessing different types of corrole-based frameworks were synthesized from a pyrrole-substituted corrole isomer (norrole L1). Oxidation of L1 afforded a unique N-Cmeso -fused pyrrolyl isonorrole L2, involving the fusion of an auxiliary pyrrolic NH moiety with a meso-sp(3) -hybridized carbon atom. Subsequently, L2 underwent macrocycle transformations to give singly and doubly N-CAr -fused N-confused corroles, L3 and L4, respectively. L3 and L4 contain fused [5.7.6.5]-tetra- and [5.6.7.7.6.5]-hexacyclic structures, respectively, prepared through lateral annulation. These skeletal transformation reactions from norrole to its isomer isonorrole and finally to N-confused corrole indicate that multiply fused porphyrinoids could be readily synthesized from pyrrole-appended confused porphyrinoids. PMID:26822959

  20. Preparation of a FeOCl derivative with pyrrole and its performance as a cathode material in a secondary lithium battery system

    NASA Astrophysics Data System (ADS)

    Sakaebe, Hikari; Higuchi, Shunichi; Kanamura, Kiyoshi; Fujimoto, Hiroyuki; Takehara, Zen-ichiro

    A FeOCl derivative is prepared in water using pyrrole (a py-FeOOH). The X-ray diffraction pattern of the product is similar to γ-FeOOH. From chemical analyses and the FT-IR spectrum, it is found that pyrrole remains in the product with an atomic ratio of Fe:N = 3:1. From discharge/charge cycling tests, it is confirmed that a py-FeOOH is rechargeable and has a specific capacity of 60 mAh g -1 between 2.0 and 4.5 V on the 20th discharge. When N-methylpyrrole (which has similar structure) is used instead of pyrrole, the derivative yields larger capacity during ten cycles.

  1. The evidence of the mode selectivity of the infrared predissociation reaction of the hydrogen bonds in the aniline water pyrrole cluster cation

    NASA Astrophysics Data System (ADS)

    Nakanaga, Taisuke; Piracha, Naveed K.; Ito, Fumiyuki

    2001-10-01

    The infrared spectrum of aniline-water-pyrrole cluster cation has been measured in the 3 μm region. Four strong vibrational bands were observed at 3313, 3515, 3637, and 3721 cm-1, and the cluster dissociated into fragments in two reaction paths, AWP +→AW ++P and AWP +→AP ++W (A: aniline, W: water, P: pyrrole) when it absorbed an infrared photon. The branching ratio (AW +/AP +) has been determined to be 0.20±0.02 for the NH stretching vibration of aniline ( 3313 cm-1, hydrogen-bonded to pyrrole) and 0.14±0.03 for the other three bands. This vibrational mode dependence should be due to the fast energy transfer from the NH to the intermolecular vibration through the hydrogen bond.

  2. Hepatoselectivity of statins: design and synthesis of 4-sulfamoyl pyrroles as HMG-CoA reductase inhibitors.

    PubMed

    Park, William K C; Kennedy, Robert M; Larsen, Scott D; Miller, Steve; Roth, Bruce D; Song, Yuntao; Steinbaugh, Bruce A; Sun, Kevin; Tait, Bradley D; Kowala, Mark C; Trivedi, Bharat K; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina H; Robertson, Andrew; Sekerke, Catherine

    2008-02-01

    4-Sulfamoyl pyrroles were designed as novel hepatoselective HMG-CoA reductase inhibitors (statins) to reduce myalgia, a statin-induced adverse effect. The compounds were prepared via a [3+2] cycloaddition of a Münchnone with a sulfonamide-substituted alkyne. We identified compounds with greater selectivity for hepatocytes compared to L6-myocytes than rosuvastatin and atorvastatin. There was an inverse correlation of myocyte potencies and ClogP values. A number of analogs were effective at reducing cholesterol in acute and chronic in vivo models but they lacked sufficient chronic in vivo activity to warrant further development. PMID:18155906

  3. Ru-Catalysed C–H Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies

    PubMed Central

    Sollert, Carina; Devaraj, Karthik; Orthaber, Andreas; Gates, Paul J; Pilarski, Lukasz T

    2015-01-01

    The Ru-catalysed C2–H arylation of indoles and pyrroles by using boronic acids under oxidative conditions is reported. This reaction can be applied to tryptophan derivatives and tolerates a wide range of functional groups on both coupling partners, including bromides and iodides, which can be further derivatised selectively. New indole-based ruthenacyclic complexes are described and investigated as possible intermediates in the reaction. Mechanistic studies suggest the on-cycle intermediates do not possess a para-cymene ligand and that the on-cycle metalation occurs through an electrophilic attack by the Ru centre. PMID:25689052

  4. Discovery, synthesis, and biological evaluation of novel pyrrole derivatives as highly selective potassium-competitive acid blockers.

    PubMed

    Nishida, Haruyuki; Hasuoka, Atsushi; Arikawa, Yasuyoshi; Kurasawa, Osamu; Hirase, Keizo; Inatomi, Nobuhiro; Hori, Yasunobu; Sato, Fumihiko; Tarui, Naoki; Imanishi, Akio; Kondo, Mitsuyo; Takagi, Terufumi; Kajino, Masahiro

    2012-06-15

    To discover a gastric antisecretory agent more potent than existing proton pump inhibitors, novel pyrrole derivatives were synthesized, and their H(+),K(+)-ATPase inhibitory activities and inhibitory action on histamine-stimulated gastric acid secretion in rats were evaluated. Among the compounds synthesized, compound 17a exhibited selective and potent H(+),K(+)-ATPase inhibitory activity through reversible and K(+)-competitive ionic binding; furthermore, compound 17c exhibited potent inhibitory action on histamine-stimulated gastric acid secretion in rats and Heidenhain pouch dogs. PMID:22579619

  5. Efficient and green synthesis of tetrasubstituted pyrroles promoted by task-specific basic ionic liquids as catalyst in aqueous media.

    PubMed

    Yavari, Issa; Kowsari, Elaheh

    2009-11-01

    Synthesis of tetrasubstituted pyrroles by the three-component condensation reaction of acid chlorides, dialkyl acetylenedicarboxylates, and amino acids in the presence of various room-temperature ionic liquids (RTILs) as catalysts in water is reported. Among the ionic liquids used, the basic functionalized ionic liquid, butyl methyl imidazolium hydroxide [bmim]OH, was the most effective catalyst. The influence of reaction temperature, reaction time, and amount of ionic liquid on the reaction was investigated. The [bmim]OH/H(2)O catalyst system could be reused for at least five recycles without appreciable loss of efficiency. PMID:19381850

  6. Novel reversible monoamine oxidase A inhibitors: highly potent and selective 3-(1H-pyrrol-3-yl)-2-oxazolidinones.

    PubMed

    Valente, Sergio; Tomassi, Stefano; Tempera, Giampiero; Saccoccio, Stefania; Agostinelli, Enzo; Mai, Antonello

    2011-12-01

    Monoamine oxidases (MAOs) are involved in various psychiatric and neurodegenerative disorders; hence, MAO inhibitors are useful agents in the therapy of Parkinson's disease, Alzheimer's dementia, and depression syndrome. Herein we report a novel series of 3-(1H-pyrrol-3-yl)-2-oxazolidinones 3-7 as reversible, highly potent and selective anti-MAO-A agents. In particular, 4b, 5b, and 4c showed a K(i-MAO-A) of 0.6, 0.8, and 1 nM, respectively, 4c being 200000-fold selective for MAO-A with respect to MAO-B. PMID:22017497

  7. A study on the spectroscopy and photophysics of N-phenyl pyrrole and N-phenyl pyrazole

    NASA Astrophysics Data System (ADS)

    Sarkar, Aindrila; Chakravorti, Sankar

    1995-03-01

    Comprehensive spectroscopic and photophysical studies of N-phenyl pyrrole (PPr) and N-phenyl pyrazole (PPz) in different solvents show that a new emission band appears due to aggregation of PPr in water. The presence of β-cyclodextrin (β-CD) in aqueous solution of PPr causes deaggregation but the twisted intramolecular charge transfer emission ceases due to the cavity effect. In PPz, aggregation and TICT emission are absent. Protonation in PPz is restricted to a single site only at very high acid concentration. Both the molecules are planar in the ground state.

  8. [N,P]-pyrrole PdCl2 complexes catalyzed the formation of dibenzo-α-pyrone and lactam analogues.

    PubMed

    Suárez-Meneses, J V; Oukhrib, A; Gouygou, M; Urrutigoïty, M; Daran, J-C; Cordero-Vargas, A; Ortega-Alfaro, M C; López-Cortés, J G

    2016-06-21

    We herein report the synthesis and catalytic application of a new family of [N,P] ligands based on the pyrrole ring with alpha-phosphine or phosphole units. Their palladium complexes (3a-d) were obtained in very good yields and their catalytic properties were evaluated in the direct intramolecular arylation to obtain both benzopyranones and phenanthridinones. The air stable complex 3a exhibited the best catalytic performance of this series of complexes, using 1 mol% of catalyst in combination with microwaves to promote this reaction. PMID:27221355

  9. Strongly adherent polypyrrole coatings obtained by electropolymerization of pyrrole on oxidizable metals in aqueous electrolytic media II. Zinc and zinc coated steel

    SciTech Connect

    Ferreira, C.A.; Zaid, B.; Aeiyach, S.; Lacaze, P.C.

    1996-01-01

    Electropolymerization of pyrrole was carried out on Zn electrodes in aqueous solution of oxalate, after the Zn surface had been chemically or electrochemically treated with sulfides. Very homogeneous and strongly adherent polypyrrole (PPy) coatings were obtained on these modified surfaces with galvanostatic polarization in an aqueous medium containing 0.5M pyrrole and 0.1M K{sub 2}C{sub 2}O{sub 4}. In the neutral state the adherence of PPy failed but could be improved if the coating was cured or over-oxidized. {copyright} {ital 1996 American Institute of Physics.}

  10. Chemodivergent, One-Pot, Multi-Component Synthesis of Pyrroles and Tetrahydropyridines under Solvent- and Catalyst-Free Conditions Using the Grinding Method.

    PubMed

    Dhinakaran, Isaivani; Padmini, Vediappen; Bhuvanesh, Nattamai

    2016-05-01

    A highly efficient, chemoselective synthesis of a library of polysubstituted pyrroles and tetrahydropyridines has been achieved through the one-pot, multicomponent reactions of ethyl (E)-3-(aryl/alkyl amino) acrylates, 2,2-dihydroxy-1-arylethan-1-ones, and malononitrile under solvent- and catalyst-free grinding conditions. The selective formation of pyrrole or tetrahydropyridines relied on substitution of the N-aryl of ethyl (E)-3-(4-arylamino) acrylates. These reactions presumably occurred via a domino Knoevenagel condensation and Michael addition followed by an intramolecular cyclization sequence of reactions in a single transformation. PMID:26972275

  11. One Step Continuous Flow Synthesis of Highly Substituted Pyrrole-3-Carboxylic Acid Derivatives via in situ Hydrolysis of tert-Butyl Esters

    PubMed Central

    Herath, Ananda; Cosford, Nicholas D. P.

    2010-01-01

    The first one-step, continuous flow synthesis of pyrrole-3-carboxylic acids directly from tert-butyl acetoacetates, amines and 2-bromoketones is reported. The HBr generated as a by-product in the Hantzsch reaction was utilized in the flow method to saponify the t-butyl esters in situ to provide the corresponding acids in a single microreactor. The protocol was used in the multistep synthesis of pyrrole-3-carboxamides, including two CB1 inverse agonists, directly from commercially available starting materials in a single continuous process. PMID:20964284

  12. Design, synthesis and biological evaluation of hetero-aromatic moieties substituted pyrrole-2-carbonitrile derivatives as dipeptidyl peptidase IV inhibitors.

    PubMed

    Ji, Xun; Su, Mingbo; Wang, Jiang; Deng, Guanghui; Deng, Sisi; Li, Zeng; Tang, Chunlan; Li, Jingya; Li, Jia; Zhao, Linxiang; Jiang, Hualiang; Liu, Hong

    2014-03-21

    A series of novel hetero-aromatic moieties substituted α-amino pyrrole-2-carbonitrile derivatives was designed and synthesized based on structure-activity relationships (SARs) of pyrrole-2-carbonitrile inhibitors. All compounds demonstrated good dipeptidyl peptidase IV (DPP4) inhibitory activities (IC50 = 0.004-113.6 μM). Moreover, compounds 6h (IC50 = 0.004 μM) and 6n (IC50 = 0.01 μM) showed excellent inhibitory activities against DPP4, good selectivity (compound 6h, selective ratio: DPP8/DPP4 = 450.0; DPP9/DPP4 = 375.0; compound 6n, selective ratio: DPP8/DPP4 = 470.0; DPP9/DPP4 = 750.0) and good efficacy in an oral glucose tolerance test in ICR mice. Furthermore, compounds 6h and 6n demonstrated moderate PK properties (compound 6h, F% = 37.8%, t1/2 = 1.45 h; compound 6n, F% = 16.8%, t1/2 = 3.64 h). PMID:24531224

  13. An experimental study of low-pressure premixed pyrrole/oxygen/argon flames with tunable synchrotron photoionization

    SciTech Connect

    Tian, Zhenyu; Li, Yuyang; Zhang, Taichang; Qi, Fei; Zhu, Aiguo; Cui, Zhifeng

    2007-10-15

    Two premixed laminar pyrrole/oxygen/argon flames at 3.33 kPa (25 Torr) with equivalence ratios of 0.55 (C/O/N = 1:5.19:0.25) and 1.84 (C/O/N = 1:1.56:0.25) have been investigated using tunable synchrotron photoionization and molecular-beam mass spectrometry techniques. All observed flame species, including some nitrogen-containing intermediates, have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of species including reactants, intermediates, and products have been determined by scanning burner position at some selected photon energies near ionization thresholds, and flame temperature has been measured by a Pt/Pt-13% Rh thermocouple. The results indicate that N{sub 2}, NO, and NO{sub 2} are the major nitrogenous products, while hydrogen cyanide, isocyanic acid, and 2-propenenitrile are the most important nitrogen-containing intermediates in pyrrole flames. Radicals such as methyl, propargyl, allyl, cyanomethyl, n-propyl, isobutyl, cyclopentadienyl, phenyl, cyclohexyl, phenoxy, and 4-methylbenzyl are observed as well. Moreover, ethenol and methylacrylonitrile are also detected. Reaction pathways involving the major species are proposed. The new results will be useful in developing a kinetic model of nitrogenous compound combustion. (author)

  14. Synthesis, Antimicrobial and cytotoxic activity of New Heterocyclic Hybrids Based on 2,5-Dimethylpyrrole and Pyrrole Scaffolds

    PubMed Central

    Joshi, S. D.; More, U. A.; Kulkarni, V. H.

    2013-01-01

    A series of 4-(2,5-dimethylpyrrol-1-yl)/4-pyrrol-1-yl benzoic acid hydrazide analogs, some derived triazoles, azetidinones, thiazolidinones, and pyrroles have been synthesized in good yields and structures of these compounds were established by IR, 1H NMR, 13C NMR, mass spectral, and elemental analysis. These compounds were evaluated for their preliminary in vitro antibacterial, antifungal, and antitubercular activity against Mycobacterium tuberculosis H37 Rv strain by the broth dilution assay method. Twenty one of these compounds displayed good antimicrobial activity, with a MIC value of 1-4 μg/ml. Several compounds 4c, 8-10, 15b-15h, and 16b-16d exhibited good in vitro antitubercular activity with MIC value 1-2 μg/ml. Further, some title compounds were also assessed for their cytotoxic activity (IC50) against mammalian Vero cell lines and A549 (lung adenocarcinoma) cell lines using the MTT assay method. The results revealed that these compounds exhibit antitubercular activity at non-cytotoxic concentrations. PMID:24082347

  15. Conductivity Measurements of Pyrrole Molecules Incorporated into Chemically Adsorbed Monolayer by Conducting Probe Technique in Atomic Force Microscope

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shin‑ichi; Ogawa, Kazufumi

    2006-03-01

    A monomolecular layer containing pyrrolyl groups at the surface was prepared between two parallel Pt electrodes on a glass substrate by a chemical adsorption technique using N-[11-(trichlorosilyl)undecyl] pyrrole (PNN). Then, the pyrrolyl was polymerized with pure water by applying a DC voltage of 10 V between the two Pt electrodes. It was confirmed using an optical microscope that many electric paths were formed between the two Pt electrodes by a decoration technique using electrochemical polymerization in an aqueous medium containing pyrrole after the polymerization. Next, a conductive probe of an atomic force microscope (AFM) was used to examine an electrical polymerized path through the surface of the polypyrrolyl group in a chemically adsorbed monomolecular layer. The resistance of one electric path in the monomolecular layer was measured using an AFM with an attached Au-covered tip at room temperature. With a measurement volume of about 0.2 nm (the thickness of the electric path in the monomolecular layer) × 200 μm (the average width of the electric path) × 100 μm (the distance between the Pt electrode and the Au-covered AFM tip), the resistance at room temperature of one electric path was 4 k Ω under ambient conditions. From the results in the atmosphere, the conductivity of a super long conjugated polypyrrolyl group without any dopant in a lateral direction was ohmically estimated to be at least 6.0 × 105 S/m.

  16. Triflic acid controlled successive annelation of aromatic sulfonamides: An efficient one-pot synthesis of N-sulfonyl pyrroles, indoles and carbazoles

    PubMed Central

    Abid, Mohammed; Teixeira, Liliana; Török, Béla

    2009-01-01

    A novel one-pot synthesis of N-substituted heterocycles via successive cyclization/annelation starting from primary sulfonamides is described. This process leads directly to N-sulfonyl pyrroles, indoles and carbazoles. The selection of appropriate reactant/triflic acid ratio successfully controls the formation of the desired product. PMID:19629194

  17. One-pot nitro-Mannich/hydroamination cascades for the direct synthesis of 2,5-disubstituted pyrroles using base and gold catalysis.

    PubMed

    Barber, David M; Sanganee, Hitesh; Dixon, Darren J

    2011-04-21

    An efficient, easy to perform, one-pot reaction cascade for the synthesis of 2,5-disubstituted pyrroles from p-toluenesulfonyl protected imines and 4-nitrobut-1-yne under a combination of base and gold(III) catalysis is reported. PMID:21399786

  18. Supramolecular organization of calix[4]pyrrole with a methyl-trialkylammonium anion exchanger leads to remarkable reversal of selectivity for sulfate extraction vs. nitrate

    SciTech Connect

    Borman, Christopher J; Custelcean, Radu; Hay, Benjamin; Bill, Nathan; Sessler, Jonathan L.; Moyer, Bruce A

    2011-01-01

    meso-Octamethylcalix[4]pyrrole (C4P) enhances sulfate selectivity in solvent extraction by Aliquat 336N, an effect ascribed to the supramolecular preorganization and thermodynamic stability imparted by insertion of the methyl group of the Aliquat cation into the cup of C4P in its cone conformation.

  19. Reconciling Experiment and Theory in the Use of Aryl-Extended Calix[4]pyrrole Receptors for the Experimental Quantification of Chloride–π Interactions in Solution

    PubMed Central

    Bauzá, Antonio; Quiñonero, David; Frontera, Antonio; Ballester, Pablo

    2015-01-01

    In this manuscript we consider from a theoretical point of view the recently reported experimental quantification of anion–π interactions (the attractive force between electron deficient aromatic rings and anions) in solution using aryl extended calix[4]pyrrole receptors as model systems. Experimentally, two series of calix[4]pyrrole receptors functionalized, respectively, with two and four aryl rings at the meso positions, were used to assess the strength of chloride–π interactions in acetonitrile solution. As a result of these studies the contribution of each individual chloride–π interaction was quantified to be very small (<1 kcal/mol). This result is in contrast with the values derived from most theoretical calculations. Herein we report a theoretical study using high-level density functional theory (DFT) calculations that provides a plausible explanation for the observed disagreement between theory and experiment. The study reveals the existence of molecular interactions between solvent molecules and the aromatic walls of the receptors that strongly modulate the chloride–π interaction. In addition, the obtained theoretical results also suggest that the chloride-calix[4]pyrrole complex used as reference to dissect experimentally the contribution of the chloride–π interactions to the total binding energy for both the two and four-wall aryl-extended calix[4]pyrrole model systems is probably not ideal. PMID:25913375

  20. Spectroscopic and quantum chemical correlation for structural evaluation, chemical reactivity and non-linear optical property investigation of two chalcone having pyrrole moiety: A comparative study

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam; Baboo, Vikas; Kumar, Yashvinder

    2015-04-01

    As part of study of pyrrole-chalcone, ethyl 4-[3-(4-chloro-phenyl)-acryloyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate (ECADPC) and ethyl 3,5-dimethyl-4-[3-(3-nitro-phenyl)-acryloyl]-1H-pyrrole-2-carboxylate (EDNAPC) have been synthesized by Claisen-Schmidt condensation using chloro- and nitro- substituted aromatic aldehyde and ethyl 3,5-dimetyl-4-acetyl-1H-pyrrole-2-carboxylate. The products were characterized by 1H NMR, UV-Visible, FT-IR spectroscopic methods and Quantum chemical calculations. Conformational analysis, normal mode frequencies and corresponding vibrational assignments based on potential energy distribution study revealed that ECADPC and EDNAPC exist in dimer form in solid state. 'Quantum theory of Atoms in molecules' (QTAIM) analysis has been performed to know the strength of intra- and intermolecular interactions. The UV-Visible spectra study reveals that the compounds are almost transparent in the visible region. Angular distribution of the probability density for population conformational analysis of ECADPC and EDNAPC are determined by analysis of the potential energy surface (PES). The calculated static first hyperpolarizability (β0) value for monomers of ECADPC and EDNAPC are 17.078 × 10-30 and 2.344 × 10-30 esu respectively, infers ECADPC to be more suitable for non-linear optical (NLO) response than EDNAPC. The electronic descriptors analysis predicts the nature of local reactive sites within the molecule.

  1. Metal-Free, Multicomponent Synthesis of Pyrrole-Based π-Conjugated Polymers from Imines, Acid Chlorides, and Alkynes.

    PubMed

    Kayser, Laure V; Vollmer, Moritz; Welnhofer, Merve; Krikcziokat, Hanna; Meerholz, Klaus; Arndtsen, Bruce A

    2016-08-24

    Multicomponent coupling reactions (MCRs) are becoming increasingly used in the synthesis of macromolecules, as they can allow the rapid generation of libraries of materials as a method to tune properties. MCRs could prove particularly useful in the synthesis of π-conjugated polymers in which structural changes are necessary for fine-tuning of electronic properties. We describe here the first metal-free multicomponent approach to conjugated polymers. This reaction exploits the coupling of imines, acid chlorides, and (catechyl)PPh to generate phospha-münchnone-containing polymers, which can be converted to poly(pyrroles) via cycloaddition. The platform allows for the efficient synthesis of families of high molecular weight polymers in one step from readily available monomers. PMID:27471822

  2. Quantum Monte Carlo for the x-ray absorption spectrum of pyrrole at the nitrogen K-edge

    SciTech Connect

    Zubarev, Dmitry Yu.; Austin, Brian M.; Lester, William A. Jr.

    2012-04-14

    Fixed-node diffusion Monte Carlo (FNDMC) is used to simulate the x-ray absorption spectrum of a gas-phase pyrrole molecule at the nitrogen K-edge. Trial wave functions for core-excited states are constructed from ground-state Kohn-Sham determinants substituted with singly occupied natural orbitals from configuration interaction with single excitations calculations of the five lowest valence-excited triplet states. The FNDMC ionization potential (IP) is found to lie within 0.3 eV of the experimental value of 406.1 {+-} 0.1 eV. The transition energies to anti-bonding virtual orbitals match the experimental spectrum after alignment of IP values and agree with the existing assignments.

  3. Novel Octahydropyrrolo[3,4-c]pyrroles Are Selective Orexin-2 Antagonists: SAR Leading to a Clinical Candidate.

    PubMed

    Letavic, Michael A; Bonaventure, Pascal; Carruthers, Nicholas I; Dugovic, Christine; Koudriakova, Tatiana; Lord, Brian; Lovenberg, Timothy W; Ly, Kiev S; Mani, Neelakandha S; Nepomuceno, Diane; Pippel, Daniel J; Rizzolio, Michele; Shelton, Jonathan E; Shah, Chandra R; Shireman, Brock T; Young, Lana K; Yun, Sujin

    2015-07-23

    The preclinical characterization of novel octahydropyrrolo[3,4-c]pyrroles that are potent and selective orexin-2 antagonists is described. Optimization of physicochemical and DMPK properties led to the discovery of compounds with tissue distribution and duration of action suitable for evaluation in the treatment of primary insomnia. These selective orexin-2 antagonists are proven to promote sleep in rats, and this work ultimately led to the identification of a compound that progressed into human clinical trials for the treatment of primary insomnia. The synthesis, SAR, and optimization of the pharmacokinetic properties of this series of compounds as well as the identification of the clinical candidate, JNJ-42847922 (34), are described herein. PMID:26087021

  4. A disposable, reagentless, third-generation glucose biosensor based on overoxidized poly(pyrrole)/tetrathiafulvalene-tetracyanoquinodimethane composite.

    PubMed

    Palmisano, Francesco; Zambonin, Pier Giorgio; Centonze, Diego; Quinto, Maurizio

    2002-12-01

    A disposable glucose biosensor based on glucose oxidase immobilized on tetrathiafulvalene-tetracyanoquinodimethane (ITF-TCNQ) conducting organic salt synthesized in situ onto an overoxidized poly(pyrrole) (PPy(ox).) film is described. The TIF-TCNQ crystals grow through the nonconducting polypyrrole film (ensuring electrical connection to the underlying Pt electrode) and emerge from the film forming a treelike structure. The PPy(ox) film prevents the interfering substances from reaching the electrode surface. The sensor behavior can be modeled by assuming a direct reoxidation of the enzyme at the surface of the TTF-TCNQ crystals. A heterogeneous rate constant around 10(-6) - 10(-7) cm s(-1) has been estimated. The biosensor is nearly oxygen- and interference-free and when integrated in a flow injection system displays a remarkable sensitivity (70 nA/mM) and stability. PMID:12498183

  5. Large area in situ fabrication of poly(pyrrole)-nanowires on flexible thermoplastic films using nanocontact printing

    NASA Astrophysics Data System (ADS)

    Garcia-Cruz, Alvaro; Lee, Michael; Marote, Pedro; Zine, Nadia; Sigaud, Monique; Bonhomme, Anne; Pruna, Raquel; Lopez, Manuel; Bausells, Joan; Jaffrezic, Nicole; Errachid, Abdelhamid

    2016-08-01

    Highly efficient nano-engineering tools will certainly revolutionize the biomedical and sensing devices research and development in the years to come. Here, we present a novel high performance conducting poly(pyrrole) nanowires (PPy-NW) patterning technology on thermoplastic surfaces (poly(ethylene terephthalate (PETE), poly(ethylene 2,6-naphthalate (PEN), polyimide (PI), and cyclic olefin copolymer) using nanocontact printing and controlled chemical polymerization (nCP-CCP) technique. The technique uses a commercial compact disk as a template to produce nanopatterned polydimethylsiloxane (PDMS) stamps. The PDMS nanopatterned stamp was applied to print the PPy-NWs and the developed technology of nCP-CCP produced 3D conducting nanostructures. This new and very promising nanopatterning technology was achieved in a single step and with a low cost of fabrication over large areas.

  6. The development of conductive surfaces by a diffusion-limited in situ polymerization of pyrrole in solfonated polystyrene ionomers

    SciTech Connect

    De Jesus, M.C.; Weiss, R.A.

    1996-10-01

    Surface conductive polymer was developed by in situ oxidative polymerization of pyrrole in lightly sulfonated polystyrene ionomers (SPS) using a chemical oxidative process. The polymerization only occurred where the monomer and FeCl{sub 3} oxidizing agent could mutually diffuse which resulted in a reaction confined to a surface layer of the host polymer. The amount of PPy incorporated during the polymerization as well as the surface conductivity attained were function of the sulfonation level. The mechanical properties of the composite were significantly improved above Tg, which is believed to be a combination of two effects: formation of a physical network due to intermolecular interactions between the two polymers and mechanical reinforcement due to the rigidity of the PPy.

  7. Hemispherand-Strapped Calix[4]pyrrole: An Ion-pair Receptor for the Recognition and Extraction of Lithium Nitrite.

    PubMed

    He, Qing; Zhang, Zhan; Brewster, James T; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-08-10

    The hemispherand-strapped calix[4]pyrrole (1) acts as an ion pair receptor that exhibits selectivity for lithium salts. In organic media (CD2Cl2 and CD3OD, v/v, 9:1), receptor 1 binds LiCl with high preference relative to NaCl, KCl, and RbCl. DFT calculations provided support for the observed selectivity. Single crystal structures of five different lithium ion-pair complexes of 1 were obtained. In the case of LiCl, a single bridging water molecule between the lithium cation and chloride anion was observed, while tight contact ion pairs were observed in the case of the LiBr, LiI, LiNO3, and LiNO2 salts. Receptor 1 proved effective as an extractant for LiNO2 under both model solid-liquid and liquid-liquid extraction conditions. PMID:27442768

  8. Highly Sensitive Bisphenol-A Electrochemical Aptasensor Based on Poly(Pyrrole-Nitrilotriacetic Acid)-Aptamer Film.

    PubMed

    Kazane, Imen; Gorgy, Karine; Gondran, Chantal; Spinelli, Nicolas; Zazoua, Ali; Defrancq, E; Cosnier, Serge

    2016-07-19

    An electrochemical highly sensitive aptasensor was developed based on electropolymerized poly(pyrrole-nitrilotriacetic) acid film and a new aptamer functionalized by a pentahistidine peptide for the quantification of bisphenol A. A surface coverage of antibisphenol A aptamer of 1.84 × 10(-10) mol cm(-2) was estimated from the electrochemical signal of the [Ru(III)(NH3)6](3+) complex bound by electrostatic interactions onto the aptamer-modified electrode. The binding of bisphenol A onto the polymer film was successfully characterized by electrochemical methods as square wave voltammetry and electrochemical impedance spectroscopy measurements. The designed label-free impedimetric aptasensor displayed a wide linear range from 10(-11) to 10(-6) mol L(-1) with a sensitivity of 372 Ω per unit of log of concentration and an excellent specificity toward interfering agents such as 4,4'-dihydroxybiphenyl and bisphenol P. PMID:27332710

  9. A role of nanotube dangling pyrrole and oxygen functions in the electrochemical synthesis of polypyrrole/MWCNTs hybrid materials

    NASA Astrophysics Data System (ADS)

    Krukiewicz, Katarzyna; Herman, Artur P.; Turczyn, Roman; Szymańska, Katarzyna; Koziol, Krzysztof K. K.; Boncel, Sławomir; Zak, Jerzy K.

    2014-10-01

    The effect of the functionalization of multi-walled carbon nanotubes (MWCNTs) on the process of electrochemical co-deposition of MWCNTs and polypyrrole (PPy), as well as the morphology of obtained composites have been demonstrated. As the nanotube components of the hybrids, three types of MWCNT were used, namely c-CVD derived (pristine) MWCNTs, their oxidized counterparts MWCNT-Ox and pyrrole-modified MWCNT-Py. The stability of pristine and functionalized MWCNTs (f-MWCNT) dispersions in tetrahydrofuran and water was studied together with the description of the process of formation PPy/(f-)MWCNT hybrid materials via electrochemical co-deposition. The structural and morphological properties of the hybrids were characterized by Raman spectroscopy, scanning electron microscopy and atomic force microscopy revealing substantial differences among hybrid materials in their surface morphology and the influence of MWCNT functionalization on the orientation of growing PPy chains.

  10. Differential Effects of Etomidate and its Pyrrole Analogue Carboetomidate on the Adrenocortical and Cytokine Responses to Endotoxemia

    PubMed Central

    Pejo, Ervin; Feng, Yan; Chao, Wei; Cotten, Joseph F; Ge, Ri Le; Raines, Douglas E

    2011-01-01

    Objective We developed a novel pyrrole analogue of etomidate, (R)-ethyl 1-(1-phenylethyl)-1H-pyrrole-2-carboxylate (carboetomidate), which retains etomidate’s desirable anesthetic and hemodynamic properties but lacks its potent inhibitory affect on adrenocorticotropic hormone-stimulated steroid synthesis. The objective of this study was to test the hypothesis that in contrast to etomidate, carboetomidate neither suppresses the adrenocortical response to endotoxemia nor enhances the accompanying production of pro-inflammatory cytokines. Design Animal study Setting University research laboratory Subjects Male Sprague-Dawley rats Interventions For both single and multiple anesthetic dose studies, rats were injected with Escherichia coli lipopolysaccharide immediately followed by a hypnotic dose of etomidate, carboetomidate or vehicle alone (dimethyl sulfoxide) as a control. For single dose studies, no additional anesthetic (or vehicle) was administered. For multiple anesthetic dose studies, additional doses of anesthetic (or vehicle) were administered every 15 min for a total of eight anesthetic (or vehicle) doses. Measurements and Main Results Plasma adrenocorticotropic hormone, corticosterone, and cytokine concentrations were measured before lipopolysaccharide administration and intermittently throughout the 5 hour experiment. In single anesthetic dose studies, plasma adrenocorticotropic hormone and cytokine concentrations were not different at any time point among the etomidate, carboetomidate, and vehicle groups whereas plasma corticosterone concentrations were briefly (60–120 min) reduced in the etomidate group. In multiple anesthetic dose studies, plasma corticosterone concentrations were persistently lower and peak plasma IL-1β and IL-6 concentrations were higher in the etomidate group versus the carboetomidate and control groups. Peak plasma IL-10 concentrations were similarly elevated in the etomidate and carboetomidate groups versus the control group

  11. Excited state non-adiabatic dynamics of pyrrole: A time-resolved photoelectron spectroscopy and quantum dynamics study

    SciTech Connect

    Wu, Guorong; Neville, Simon P.; Worth, Graham A.; Schalk, Oliver; Sekikawa, Taro; Ashfold, Michael N. R.; Stolow, Albert

    2015-02-21

    The dynamics of pyrrole excited at wavelengths in the range 242-217 nm are studied using a combination of time-resolved photoelectron spectroscopy and wavepacket propagations performed using the multi-configurational time-dependent Hartree method. Excitation close to the origin of pyrrole’s electronic spectrum, at 242 and 236 nm, is found to result in an ultrafast decay of the system from the ionization window on a single timescale of less than 20 fs. This behaviour is explained fully by assuming the system to be excited to the A{sub 2}(πσ{sup ∗}) state, in accord with previous experimental and theoretical studies. Excitation at shorter wavelengths has previously been assumed to result predominantly in population of the bright A{sub 1}(ππ{sup ∗}) and B{sub 2}(ππ{sup ∗}) states. We here present time-resolved photoelectron spectra at a pump wavelength of 217 nm alongside detailed quantum dynamics calculations that, together with a recent reinterpretation of pyrrole’s electronic spectrum [S. P. Neville and G. A. Worth, J. Chem. Phys. 140, 034317 (2014)], suggest that population of the B{sub 1}(πσ{sup ∗}) state (hitherto assumed to be optically dark) may occur directly when pyrrole is excited at energies in the near UV part of its electronic spectrum. The B{sub 1}(πσ{sup ∗}) state is found to decay on a timescale of less than 20 fs by both N-H dissociation and internal conversion to the A{sub 2}(πσ{sup ∗}) state.

  12. Synthesis, characterization, molecular docking and biological studies of self assembled transition metal dithiocarbamates of substituted pyrrole-2-carboxaldehyde.

    PubMed

    Nami, Shahab A A; Ullah, Irfan; Alam, Mahboob; Lee, Dong-Ung; Sarikavakli, Nursabah

    2016-07-01

    A series of self assembled 3d transition metal dithiocarbamate, M(pdtc) [where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)] have been synthesized and spectroscopically characterized. The bidentate dithiocarbamate ligand Na2pdtc (Disodium-1,4-phenyldiaminobis (pyrrole-1-sulfino)dithioate) was prepared by insertion reaction of carbondisulfide with Schiff base, N,N'-bis-(1H-pyrrol-2-ylmethylene)-benzene-1,4-diamine (L1) in basic medium. The simple substitution reaction between the metal halide and Na2pdtc yielded the title complexes in moderate yields. However, the in situ procedure gives high yield with the formation of single product as evident by TLC. Elemental analysis, IR, (1)H and (13)C NMR spectra, UV-vis., magnetic susceptibility and conductance measurements were done to characterize the complexes, M(pdtc). All the evidences suggest that the complexes have tetrahedral geometry excepting Cu(II) which is found to be square planar. A symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the complexes. The conductivity data show that the complexes are non-electrolyte in nature. The anti-oxidant activity of the ligand, Na2pdtc and its transition metal complexes, M(pdtc) have been carried out using DPPH and Cu(pdtc) was found to be most effective. The anti-microbial activity of the Na2pdtc and M(pdtc) complexes have been carried out and on this basis the molecular docking study of the most effective complex, Cu(pdtc) has also been reported. PMID:27197060

  13. Crystal structure of 3-ferrocenyl-1-phenyl-1H-pyrrole, [Fe(η5-C5H4 cC4H3 NPh)(η5-C5H5)

    PubMed Central

    Pfaff, Ulrike; Korb, Marcus; Lang, Heinrich

    2016-01-01

    The mol­ecular structure of the title compound, [Fe(C5H5)(C15H12N)], consists of a ferrocene moiety with an N-phenyl­pyrrole heterocycle bound to one cyclo­penta­dienyl ring. The 1,3-disubstitution of the pyrrole results in an L-shaped arrangement of the mol­ecule with plane inter­sections of 2.78 (17)° between the pyrrole and the N-bonded phenyl ring and of 8.17 (18)° between the pyrrole and the cyclo­penta­dienyl ring. In the crystal, no remarkable inter­molecular inter­actions are observed PMID:26870594

  14. Cadmium(II) and zinc(II) complexes of pyrrole-appended oxacarbaporphyrin: a side-on coordination mode of O-confused carbaporphyrin.

    PubMed

    Pawlicki, Miłosz; Latos-Grazyński, Lechosław; Szterenberg, Ludmiła

    2005-12-26

    A pyrrole adduct of 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin [(H,pyr)OCPH]H(2) reacted with sodium ethanolate to yield 5,20-diphenyl-10,15-di(p-tolyl)-3-ethoxy-3-(2'-pyrrol)-2-oxa-21-carbaporphyrin [(EtO,pyr)OCPH]H(2). Subsequently, "true" O-confused oxaporphyrin with a pendant pyrrole ring [(pyr)OCPH]H was formed by the addition of acid to [(EtO,pyr)OCPH]H(2), which triggered an ethanol elimination. In the course of this process, the tetrahedral-trigonal rearrangements originated at the C(3) atom. Insertion of zinc(II), cadmium(II), and nickel(II) into [(pyr)OCPH]H yielded [(pyr)OCPH]Zn(II)Cl, [(pyr)OCPH]Cd(II)Cl, and [(pyr)OCP]Ni(II). The formation of [(pyr)OCP]Ni(II) was accompanied by the C(21)H dehydrogenation step. The nickel(II) ion of [(pyr)OCP]Ni(II), coordinated to a dianionic macrocyclic ligand, is bound by three pyrrolic nitrogens and a trigonally hybridized C(21) atom of the inverted furan. The pyrrole-appended O-confused carbaporphyrin acts as a monoanionic ligand toward zinc(II) and cadmium(II) cations. Three nitrogen atoms and the C(21)H fragment of the inverted furan occupy equatorial positions. In (1)H NMR spectra, the unique inner C(21)H resonances of the inverted furan ring are located at 0.15 ppm for [(pyr)OCPH]Zn(II)Cl, and at 0.21 ppm for [(pyr)OCPH]Cd(II)Cl. The proximity of the furan fragment to the metal ion induces direct scalar couplings between the spin-active nucleus of the metal ((111/113)Cd) and the adjacent (1)H nucleus. The interaction of the metal ion and C(21)H was also reflected by significant changes in carbon chemical shifts ([(pyr)OCPH]Zn(II)Cl, 78.3 ppm; [(pyr)OCPH]Cd(II)Cl, 81.4 ppm; the free base, 101.3 ppm). The density functional theory (DFT) has been applied to model the molecular structures of zinc(II) and cadmium(II) complexes of O-confused oxaporphyrin with an appended pyrrole ring. The Cd...C(21) distance in the optimized structure exceeds the typical Cd-C bond lengths, but is much shorter than the

  15. Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

    PubMed Central

    Messaoud, Mohamed Yacine Ameur; Hedidi, Madani; Derdour, Aïcha; Chevallier, Floris; Ivashkevich, Oleg A; Matulis, Vadim E; Roisnel, Thierry; Dorcet, Vincent

    2015-01-01

    Summary The synthesis of N-arylated pyrroles and indoles is documented, as well as their functionalization by deprotonative metallation using the base in situ prepared from LiTMP and ZnCl2·TMEDA (1/3 equiv). With N-phenylpyrrole and -indole, the reactions were carried out in hexane containing TMEDA which regioselectively afforded the 2-iodo derivatives after subsequent iodolysis. With pyrroles and indoles bearing N-substituents such as 2-thienyl, 3-pyridyl, 4-methoxyphenyl and 4-bromophenyl, the reactions all took place on the substituent, at the position either adjacent to the heteroatom (S, N) or ortho to the heteroatom-containing substituent (OMe, Br). The CH acidities of the substrates were determined in THF solution using the DFT B3LYP method in order to rationalize the experimental results. PMID:26425204

  16. In situ intercalative polymerization of pyrrole in FeOCl: a new class of layered, conducting polymer-inorganic hybrid materials

    SciTech Connect

    Kanatzidis, M.G.; Tonge, L.M.; Marks, T.J.; Marcy, H.O.; Kannewurf, C.R.

    1987-06-10

    The authors report here a structural form of polypyrrole in which polymerization and intercalation of pyrrole are brought about within the constrained van der Waals gap of a layered inorganic solid (FeOCl). Oxidative intercalation of organic molecules with concomitant reduction of the inorganic lattice is well established for FeOCl, and in the present case affords a novel class of conductive polymer-inorganic hybrid materials. The reaction of FeOCl with excess neat pyrrole (60/sup 0/C) yields a material analyzing as (Ppy)/sub 0.34/FeOCl. X-ray diffraction measurements reveal high crystallinity and an increase in FeOCl interlayer (b-axis) spacing from 7.980 to 13.210 A.

  17. 3-(Dicyanomethylidene)indan-1-one-Functionalized Calix[4]arene-Calix[4]pyrrole Hybrid: An Ion-Pair Sensor for Cesium Salts.

    PubMed

    Yeon, Yerim; Leem, Soojung; Wagen, Corin; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-09-01

    A chromogenic calix[4]arene-calix[4]pyrrole hybrid ion pair receptor bearing an indane substituent at a β-pyrrolic position has been prepared. On the basis of solution-phase UV-vis spectroscopic analysis and (1)H NMR spectroscopic studies carried out in 10% methanol in chloroform, receptor 1 is able to bind only cesium ion pairs (e.g., CsF, CsCl, and CsNO3) but not the constituent cesium cation (as its perchlorate salt) or the F(-), Cl(-), or NO3(-) anions (as the tetrabutylammonium salts). It thus displays rudimentary AND logic gate behavior. Receptor 1 shows a colorimetric response to cesium ion pairs under conditions of solid-liquid (nitrobenzene) and liquid-liquid (D2O-nitrobenzene-d5) extraction. PMID:27533478

  18. Selective synthesis of substituted pyrrole-2-phosphine oxides and -phosphonates from 2H-azirines and enolates from acetyl acetates and malonates.

    PubMed

    Palacios, Francisco; Ochoa de Retana, Ana M; Vélez del Burgo, Ander

    2011-11-18

    A simple and efficient selective synthesis of 1H-pyrrole-2-phosphine oxides 3 and -phosphonates 7 by addition of enolates derived from acetyl acetates to 2H-azirinylphosphine oxide 1 and -phosphonate 6 is reported. Nucleophilic addition of enolates derived from diethyl malonate to 2H-azirines 1 and 6 led to the formation of functionalized 2-hydroxy-1H-pyrrole-5-phosphine oxide 9 and -phosphonate 10, while vinylogous α-aminoalkylphosphine oxides 14 and -phosphonate 15 may be obtained from azirines and the enolate derived from diethyl 2-phenylmalonate. Ring closure of vinylogous derivatives 14 and 15 in the presence of base led to the formation of 1,5-dihydro-3-pyrrolin-2-ones containing a phosphine oxide 17 or a phosphonate group 18. PMID:21999212

  19. Stereoselective self-sorting in the self-assembly of a Phe-Phe extended guanidiniocarbonyl pyrrole carboxylate zwitterion: formation of two diastereomeric dimers with significantly different stabilities.

    PubMed

    Rodler, Fabian; Sicking, Wilhelm; Schmuck, Carsten

    2011-07-28

    The 'dipeptide extended' guanidiniocarbonyl pyrrole carboxylate zwitterion GCP-Phe-Phe 1 forms stable dimers in DMSO. However, dimerization is highly stereoselective. Only homochiral dimers are formed and the (L,L)·(L,L) dimer (K(dim) > 10(5) M(-1)) is significantly more stable by a factor of 10(3) than the diastereomeric (D,L)·(D,L) dimer (K(dim) = 120 M(-1)). PMID:21670799

  20. Highly enantioselective Friedel-Crafts alkylation of indoles and pyrrole with β,γ-unsaturated α-ketoesters catalyzed by heteroarylidene-tethered bis(oxazoline) copper complexes.

    PubMed

    Liu, Lei; Ma, Hongli; Xiao, Yumei; Du, Fengpei; Qin, Zhaohai; Li, Nan; Fu, Bin

    2012-09-25

    The simple and cheap chiral catalyst, heteroarylidene-tethered Ph-bis(oxazoline)-Cu(OTf)(2), can efficiently catalyze the asymmetric F-C alkylation of indoles and pyrrole with β,γ-unsaturated α-ketoesters. The 3-indolyl adducts were obtained in up to >99% ee. Moreover, the 2-pyrrolyl adducts were achieved in up to 92% ee for the first time. PMID:22875174

  1. Synthesis, characterization and computational study on ethyl 4-(3-Furan-2yl-acryloyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam; Sahu, Sangeeta

    2014-11-01

    As part of study on pyrrole derivatives, we have synthesized a pyrrole chalcone derivative: ethyl 4-(3-Furan-2yl-acryloyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate (EFADPC) by aldol condensation of ethyl 3, 5-dimethyl-4-actyl-1H-pyrrole-2-carboxylate with furan-2-carbaldehyde in the presence of strong hydroxyl base as catalyst. The product EFADPC has been confirmed by spectroscopic (FT-IR, 1H NMR, and UV-visible) analyses. Quantum chemical calculation also provides good correlation with experimental data. The molecular electrostatic potential surface (MEP), natural bond orbital interactions (NBO), electronic descriptors, quantum theory of atoms' in molecules (QTAIM) and experimental FT-IR spectrum have been used to predict the sites and nature of interactions which indicate that the dimer formation with multiple interactions through Nsbnd H···O and Csbnd H···O. The vibrational analysis shows red shifts in νNsbnd H and νCdbnd O as result of dimer formation. The binding energy of dimer is calculated as 13.82, 15.24 kcal/mol using DFT, QTAIM analysis, respectively. The result of ellipticity confirms the existence of resonance assisted hydrogen bonds (RAHB) in dimer. The MEP and local reactivity descriptors analyses have been performed and the results indicate that carbonyl carbon and β-carbon of chalcone frame have been prone to nucleophilic attack and lead to large number of heterocyclic compounds such as oxirane, oxazoles, pyrazoles, pyridines, pyrimidines, and pyran.

  2. α, α', α", α'"-meso-tetrahexyltetramethyl-calix[4]pyrrole: An easy-to-prepare, isomerically pure anion extractant with enhanced solubility in organic solvents

    DOE PAGESBeta

    Williams, Neil J.; Bryantsev, Vyacheslav S.; Custelcean, Radu; Seipp, Charles A.; Moyer, Bruce A.

    2016-01-29

    α, α', α", α'"-meso-Tetrahexyltetramethyl-calix[4]pyrrole is easily obtained as a single diastereomer in a one-pot reaction. It exhibits enhanced solubility in organic solvents, including aliphatic solvents, relative to its parent meso-octamethylcalix[4]pyrrole (1). Somewhat surprisingly, the tetrahexyl derivative 2 complexes with tributylmethylammonium chloride in chloroform more strongly than does 1 as shown by NMR titrations. However, 1 and 2 exhibit comparable complexation strength in extraction experiments, the difference between the NMR and extraction results being attributed to the effect of organic-phase water in the extraction systems. Mass-action analysis indicates the formation of the predominant complex TBMA+(1 or 2)Cl– in both NMR andmore » extraction systems, and equilibrium constants are reported. x-Ray crystal structures were obtained for the free ligand 2 and its complex with tetramethylammonium chloride. In addition, the free ligand crystallises in the 1,3-alt conformation with equatorial hexyl arms. In the chloride complex with 2 in its cone conformation, the hexyl arms adopt an axial orientation, enveloping the anion. DFT calculations show this binding conformation to be the most stable, mostly owing to destabilising steric interactions involving the pyrrole C–H and alkyl C–H groups positioned equatorially.« less

  3. Comparative neurotoxicity and pyrrole-forming potential of 2,5-hexanedione and perdeuterio-2,5-hexanedione in the rat

    SciTech Connect

    DeCaprio, A.P.; Briggs, R.G.; Jackowski, S.J.; Kim, J.C.

    1988-01-01

    2,5-Hexanedione (2,5-HD), the neurotoxic metabolite of n-hexane, reacts with protein amines to form alkylpyrrole adducts. Pyrrolylation of neurofilament protein may be the initiating molecular event in 2,5-HD neuropathy. The present study compares the neurotoxic and pyrrole-forming potentials of 2,5-HD with those of perdeuterio-2,5-HD ((D10)-2,5-HD) in the rat. Due to a requirement for C-H bond breaking in the reaction mechanism, the latter derivative was expected to exhibit a primary isotope effect, thus forming the pyrrole at a slower rate. In vitro studies confirmed that (D10)-2,5-HD pyrrolylated protein at only one-third of the initial rate seen with native 2,5-HD. Prolonged incubation resulted in similar pyrrole concentrations with both derivatives. Adult, male Wistar rats were administered daily (5 days/week) ip doses of either 3.5 mmol 2,5-HD or (D10)-2,5-HD/kg/day for 17 days or 2.5 mmol/kg/day for 38 days. At termination, animals administered 2,5-HD and (D10)-2,5-HD exhibited 27 and 8% body weight loss, respectively. Moderate to severe hindlimb paralysis was present in the 2,5-HD groups while only mild effects were seen in (D10)-2,5-HD-dosed rats. Neuropathological changes were prominent in spinal cord sections from 2,5-HD-treated animals, while no effects were present in rats given the deuterated derivative. Pyrrole adduct concentrations in serum and axonal cytoskeletal proteins from 2,5-HD-treated animals were two- to threefold higher than in rats given equimolar doses of (D10)-2,5-HD. Levels of covalent crosslinking of axonal cytoskeletal proteins (assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) appeared to correlate with pyrrole concentrations. Tissue concentrations of each diketone isomer were not significantly different, indicating similar uptake of native and deuterated 2,5-HD.

  4. Sub-10 nm Platinum Nanocrystals with Size and Shape Control: Catalytic Study for Ethylene and Pyrrole Hydrogenation

    SciTech Connect

    Tsung, Chia-Kuang; Kuhn, John N.; Huang, Wenyu; Aliaga, Cesar; Hung, Ling-I; Somorjai, Gabor A.; Yang, Peidong

    2009-03-02

    Platinum nanocubes and nanopolyhedra with tunable size from 5 to 9 nm were synthesized by controlling the reducing rate of metal precursor ions in a one-pot polyol synthesis. A two-stage process is proposed for the simultaneous control of size and shape. In the first stage, the oxidation state of the metal ion precursors determined the nucleation rate and consequently the number of nuclei. The reaction temperature controlled the shape in the second stage by regulation of the growth kinetics. These well-defined nanocrystals were loaded into MCF-17 mesoporous silica for examination of catalytic properties. Pt loadings and dispersions of the supported catalysts were determined by elemental analysis (ICP-MS) and H2 chemisorption isotherms, respectively. Ethylene hydrogenation rates over the Pt nanocrystals were independent of both size and shape and comparable to Pt single crystals. For pyrrole hydrogenation, the nanocubes enhanced ring-opening ability and thus showed a higher selectivity to n-butylamine as compared to nanopolyhedra.

  5. Nuclear Localization and Gene Expression Modulation by a Fluorescent Sequence-Selective p-Anisyl-benzimidazolecarboxamido Imidazole-Pyrrole Polyamide.

    PubMed

    Kiakos, Konstantinos; Pett, Luke; Satam, Vijay; Patil, Pravin; Hochhauser, Daniel; Lee, Moses; Hartley, John A

    2015-07-23

    Synthetic pyrrole (P)-imidazole (I) containing polyamides can target predetermined DNA sequences and modulate gene expression by interfering with transcription factor binding. We have previously shown that rationally designed polyamides targeting the inverted CCAAT box 2 (ICB2) of the topoisomerase IIα (topo IIα) promoter can inhibit binding of transcription factor NF-Y, re-inducing expression of the enzyme in confluent cells. Here, the A/T recognizing fluorophore, p-anisylbenzimidazolecarboxamido (Hx) was incorporated into the hybrid polyamide HxIP, which fluoresces upon binding to DNA, providing an intrinsic probe to monitor cellular uptake. HxIP targets the 5'-TACGAT-3' sequence of the 5' flank of ICB2 with high affinity and sequence specificity, eliciting an ICB2-selective inhibition/displacement of NF-Y. HxIP is readily taken up by NIH3T3 and A549 cells, and detected in the nucleus within minutes. Exposure to the polyamide at confluence resulted in a dose-dependent upregulation of topo IIα expression and enhanced formation of etoposide-induced DNA strand breaks. PMID:26119998

  6. Maleimides (1 H-pyrrole-2,5-diones) as molecular indicators of anoxygenic photosynthesis in ancient water columns

    NASA Astrophysics Data System (ADS)

    Grice, Kliti; Gibbison, Robert; Atkinson, Jane E.; Schwark, Lorenz; Eckardt, Christian B.; Maxwell, James R.

    1996-10-01

    Maleimides (1 H-pyrrole-2,5-diones), degradation products of photosynthetic tetrapyrrole pigments, have been found for the first time in the polar fraction of the solvent extracts of two marine sediments deposited in restricted basins: Kupferschiefer (Permian) and Serpiano shale (Mid-Triassic). GC and GC—MS analyses of the TBDMS ( tertiary-butyldimethylsilyl) derivatives show a simple component distribution, dominated by Me Et maleimide, mainly of planktonic origin; Me n-Pr and Me i-Bu maleimides, present in low abundance, are thought on structural grounds to be derived from the bacteriochlorophylls c, d, or e of Chlorobiaceae (anoxygenic green sulfur bacteria). This is confirmed for Kupferschiefer by isotope ratio monitoring (irm) GCMS which shows them to be enriched in 13C as a result of their photosynthetic carbon assimilation, which takes place by the reversed tricarboxylic acid (TCA) cycle. The structurally more specific Me i-Bu maleimide is, however, slightly more enriched in 13C than Me n-Pr maleimide, suggesting that the latter is derived in part from reduction of the C 3-acid substituent at C-17 of phytoplanktonic chlorophyll. These results provide evidence for the existence in both depositional settings of microbial communities containing Chlorobiaceae. In turn, this indicates that there must have been periods when the water column was highly stratified and anoxia extended into the zone of light penetration.

  7. Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

    SciTech Connect

    Kliewer, Christopher J.; Bieri, Marco; Somorjai, Gabor A.

    2008-03-04

    Sum-frequency generation (SFG) surface vibrational spectroscopy and kinetic measurements using gas chromatography have been used to study the adsorption and hydrogenation of pyrrole over both Pt(111) and Rh(111) single-crystal surfaces at Torr pressures (3 Torr pyrrole, 30 Torr H{sub 2}) to form pyrrolidine and the minor product butylamine. Over Pt(111) at 298 K it was found that pyrrole adsorbs in an upright geometry cleaving the N-H bond to bind through the nitrogen evidenced by SFG data. Over Rh(111) at 298 K pyrrole adsorbs in a tilted geometry relative to the surface through the p-aromatic system. A pyrroline surface reaction intermediate, which was not detected in the gas phase, was seen by SFG during the hydrogenation over both surfaces. Significant enhancement of the reaction rate was achieved over both metal surfaces by adsorbing 1-methylpyrrole before reaction. SFG vibrational spectroscopic results indicate that reaction promotion is achieved by weakening the bonding between the N-containing products and the metal surface because of lateral interactions on the surface between 1-methylpyrrole and the reaction species, reducing the desorption energy of the products. It was found that the ring-opening product butylamine was a reaction poison over both surfaces, but this effect can be minimized by treating the catalyst surfaces with 1-methylpyrrole before reaction. The reaction rate was not enhanced with elevated temperatures, and SFG suggests desorption of pyrrole at elevated temperatures.

  8. Ion-regulated allosteric binding of fullerenes (C60 and C70) by tetrathiafulvalene-calix[4]pyrroles.

    PubMed

    Davis, Christina M; Lim, Jong Min; Larsen, Karina R; Kim, Dong Sub; Sung, Young Mo; Lyons, Dani M; Lynch, Vincent M; Nielsen, Kent A; Jeppesen, Jan O; Kim, Dongho; Park, Jung Su; Sessler, Jonathan L

    2014-07-23

    The effect of ionic species on the binding of fullerenes (C60 and C70) by tetrathiafulvalene-calix[4]pyrrole (TTF-C4P) receptors and the nature of the resulting supramolecular complexes (TTF-C4P + fullerene + halide anion + tetraalkylammonium cation) was studied in the solid state through single crystal X-ray diffraction methods and in dichloromethane solution by means of continuous variation plots and UV-vis spectroscopic titrations. These analyses revealed a 1:1 stoichiometry between the anion-bound TTF-C4Ps and the complexed fullerenes. The latter guests are bound within the bowl-like cup of the C4P in a ball-and-socket binding mode. The interactions between the TTF-C4P receptors and the fullerene guests are highly influenced by both the nature of halide anions and their counter tetraalkylammonium cations. Three halides (F(-), Cl(-), and Br(-)) were studied. All three potentiate the binding of the two test fullerenes by inducing a conformational change from the 1,3-alternate to the cone conformer of the TTF-C4Ps, thus acting as positive heterotropic allosteric effectors. For a particular halide anion, the choice of tetraalkylammonium salts serves to modulate the strength of the TTF-C4P-fullerene host-guest binding interactions and, in conjunction with variations in the halide anion, can be exploited to alter the inherent selectivity of the host for a given fullerene. Differences in binding are reflected in the excited state optical properties. Overall, the present four-component system provides an illustration of how host-guest binding events involving appropriately designed artificial receptors can be fine-tuned via the addition of simple ionic species as allosteric modulators. PMID:24967663

  9. Sequence-selective single-molecule alkylation with a pyrrole-imidazole polyamide visualized in a DNA nanoscaffold.

    PubMed

    Yoshidome, Tomofumi; Endo, Masayuki; Kashiwazaki, Gengo; Hidaka, Kumi; Bando, Toshikazu; Sugiyama, Hiroshi

    2012-03-14

    We demonstrate a novel strategy for visualizing sequence-selective alkylation of target double-stranded DNA (dsDNA) using a synthetic pyrrole-imidazole (PI) polyamide in a designed DNA origami scaffold. Doubly functionalized PI polyamide was designed by introduction of an alkylating agent 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI) and biotin for sequence-selective alkylation at the target sequence and subsequent streptavidin labeling, respectively. Selective alkylation of the target site in the substrate DNA was observed by analysis using sequencing gel electrophoresis. For the single-molecule observation of the alkylation by functionalized PI polyamide using atomic force microscopy (AFM), the target position in the dsDNA (∼200 base pairs) was alkylated and then visualized by labeling with streptavidin. Newly designed DNA origami scaffold named "five-well DNA frame" carrying five different dsDNA sequences in its cavities was used for the detailed analysis of the sequence-selectivity and alkylation. The 64-mer dsDNAs were introduced to five individual wells, in which target sequence AGTXCCA/TGGYACT (XY = AT, TA, GC, CG) was employed as fully matched (X = G) and one-base mismatched (X = A, T, C) sequences. The fully matched sequence was alkylated with 88% selectivity over other mismatched sequences. In addition, the PI polyamide failed to attach to the target sequence lacking the alkylation site after washing and streptavidin treatment. Therefore, the PI polyamide discriminated the one mismatched nucleotide at the single-molecule level, and alkylation anchored the PI polyamide to the target dsDNA. PMID:22320236

  10. Monocrotaline pyrrole-induced changes in angiotensin-converting enzyme activity of cultured pulmonary artery endothelial cells.

    PubMed Central

    Hoorn, C. M.; Roth, R. A.

    1993-01-01

    1. Changes in the structural and functional integrity of endothelium have been recognized as relatively early features of delayed and progressive pulmonary vascular injury caused by the pyrrolizidine alkaloid, monocrotaline (MCT). Although a number of investigators have evaluated angiotensin-converting enzyme (ACE) activity in the lungs of rats treated with MCT, the exact nature of changes in activity of this enzyme and the role they may play in MCT pneumotoxicity remain controversial. 2. We examined the direct effects of monocrotaline pyrrole (MCTP), a toxic metabolite of MCT, on cultured endothelial cell ACE activity. Post-confluent monolayers of porcine or bovine pulmonary artery endothelial cells (PECs or BECs, respectively) were treated with a single administration of MCTP at time 0; then they were examined for their ability to degrade the synthetic peptide, [3H]-benzoyl-Phe-Ala-Pro. 3. In PECs, which are relatively insensitive to the direct cytolytic effects of MCTP, monolayer ACE activity was unchanged initially but gradually decreased within 4 days after treatment with a high concentration of MCTP (150 microM). This decrease was transient, and PEC monolayer ACE activity returned to the control value by 10 days post treatment. 4. BEC monolayer ACE activity was also unchanged initially but rapidly declined within 4 days after MCTP treatment and remained depressed throughout the post treatment period. BECs were quite sensitive to the cytolytic effects of MCTP and the decline in ACE activity occurred coincident with the decrease in monolayer cellularity and appearance of marked cytotoxicity. 5. We conclude that high concentrations of MCTP decrease endothelial ACE activity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8242234

  11. Micro- to nanostructured poly(pyrrole-nitrilotriacetic acid) films via nanosphere templates: applications to 3D enzyme attachment by affinity interactions.

    PubMed

    Cernat, Andreea; Le Goff, Alan; Holzinger, Michael; Sandulescu, Robert; Cosnier, Serge

    2014-02-01

    We report the combination of latex nanosphere lithography with electropolymerization of N-substituted pyrrole monomer bearing a nitrilotriacetic acid (NTA) moiety for the template-assisted nanostructuration of poly(pyrrole-NTA) films and their application for biomolecule immobilization. The electrodes were modified by casting latex beads (100 or 900 nm in diameter) on their surface followed by electropolymerization of the pyrrole-NTA monomer and the subsequent chelation of Cu(2+) ions. The dissolution of the nanobeads leads then to a nanostructured polymer film with increased surface. Thanks to the versatile affinity interactions between the (NTA)Cu(2+) complex and histidine- or biotin-tagged proteins, both tyrosinase and glucose oxidase were immobilized on the modified electrode. Nanostructuration of the polypyrrole via nanosphere lithography (NSL) using 900- and 100-nm latex beads allows an increase in surface concentration of enzymes anchored on the functionalized polypyrrole electrode. The nanostructured enzyme electrodes were characterized by fluorescence microscopy, 3D laser scanning confocal microscopy, and scanning electron microscopy. Electrochemical studies demonstrate the increase in the amount of immobilized biomolecules and associated biosensor performances when achieving NSL compared to conventional polymer formation without bead template. In addition, the decrease in nanobead diameter from 900 to 100 nm provides an enhancement in biosensor performance. Between biosensors based on films polymerized without nanobeads and with 100-nm nanobeads, maximum current density values increase from 4 to 56 μA cm(-2) and from 7 to 45 μA cm(-2) for biosensors based on tyrosinase and glucose oxidase, respectively. PMID:23793398

  12. 3He NMR studies on helium-pyrrole, helium-indole, and helium-carbazole systems: a new tool for following chemistry of heterocyclic compounds.

    PubMed

    Radula-Janik, Klaudia; Kupka, Teobald

    2015-02-01

    The (3)He nuclear magnetic shieldings were calculated for free helium atom and He-pyrrole, He-indole, and He-carbazole complexes. Several levels of theory, including Hartree-Fock (HF), Second-order Møller-Plesset Perturbation Theory (MP2), and Density Functional Theory (DFT) (VSXC, M062X, APFD, BHandHLYP, and mPW1PW91), combined with polarization-consistent pcS-2 and aug-pcS-2 basis sets were employed. Gauge-including atomic orbital (GIAO) calculated (3)He nuclear magnetic shieldings reproduced accurately previously reported theoretical values for helium gas. (3)He nuclear magnetic shieldings and energy changes as result of single helium atom approaching to the five-membered ring of pyrrole, indole, and carbazole were tested. It was observed that (3)He NMR parameters of single helium atom, calculated at various levels of theory (HF, MP2, and DFT) are sensitive to the presence of heteroatomic rings. The helium atom was insensitive to the studied molecules at distances above 5 Å. Our results, obtained with BHandHLYP method, predicted fairly accurately the He-pyrrole plane separation of 3.15 Å (close to 3.24 Å, calculated by MP2) and yielded a sizable (3)He NMR chemical shift (about -1.5 ppm). The changes of calculated nucleus-independent chemical shifts (NICS) with the distance above the rings showed a very similar pattern to helium-3 NMR chemical shift. The ring currents above the five-membered rings were seen by helium magnetic probe to about 5 Å above the ring planes verified by the calculated NICS index. PMID:25228253

  13. Pyrrole-coupled salicylimine-based fluorescence "turn on" probe for highly selective recognition of Zn²⁺ ions in mixed aqueous media: Application in living cell imaging.

    PubMed

    Bhosale, Jitendra; Fegade, Umesh; Bondhopadhyay, Banashree; Kaur, Simanpreet; Singh, Narinder; Basu, Anupam; Dabur, Rajesh; Bendre, Ratnamala; Kuwar, Anil

    2015-06-01

    Cation sensing behaviour of a pyrrole-based derivative (2-hydroxyl 3 methyl 6 isopropyl benzaldehyde}-3,4-dimethyl-1H-pyrrole-2-carbohydrazide (receptor 3) has been explored and is found to be selective towards Zn(2+) over a variety of tested cations. The receptor 3 has shown high selectivity and sensitivity towards Zn(2+) over the other alkali, alkaline earth and transition metal ions. In the presence of Zn(2+), absorption band of receptor 3 has shown the red shift. The sensing behaviour has been suggested to continue via enhancement process which has further been supported by UV-vis absorption and theoretical density functional theory (DFT) calculations indicating the formation of a 1:1 complex between the pyrrole based receptor 3 and Zn(2+). The present work is presenting a highly selective dual channel colorimetric sensor for zinc with great sensitivity. The developed sensor was successfully applied to image intracellular Zn(2+) in living cells. PMID:25707866

  14. Comparison of the resonance-enhanced multiphoton ionization spectra of pyrrole and 2,5-dimethylpyrrole: Building toward an understanding of the electronic structure and photochemistry of porphyrins

    NASA Astrophysics Data System (ADS)

    Beames, Joseph M.; Nix, Michael G. D.; Hudson, Andrew J.

    2009-11-01

    The photophysical properties of porphyrins have relevance for their use as light-activated drugs in cancer treatment and sensitizers in solid-state solar cells. However, the appearance of their UV-visible spectra is usually explained inadequately by qualitative molecular-orbital theories. We intend to gain a better insight into the intense absorption bands, and excited-state dynamics, that make porphyrins appropriate for both of these applications by gradually building toward an understanding of the macrocyclic structure, starting with studies of smaller pyrrolic subunits. We have recorded the (1+1) and (2+1) resonance-enhanced multiphoton ionization (REMPI) spectra of pyrrole and 2,5-dimethylpyrrole between 25 600 cm-1 (390 nm) and 48 500 cm-1 (206 nm). We did not observe a (1+1) REMPI signal through the optically bright B12 (ππ ∗) and A11 (ππ ∗) states in pyrrole due to ultrafast deactivation via conical intersections with the dissociative A12 (πσ ∗) and B11 (πσ ∗) states. However, we did observe (2+1) REMPI through Rydberg states with a dominant feature at 27 432 cm-1 (two-photon energy, 54 864 cm-1) assigned to a 3d←π transition. In contrast, 2,5-dimethylpyrrole has a broad and structured (1+1) REMPI spectrum between 36 000 and 42 500 cm-1 as a result of vibronic transitions to the B12 (ππ ∗) state, and it does not show the 3d←π Rydberg transition via (2+1) REMPI. We have complemented the experimental studies by a theoretical treatment of the excited states of both molecules using time-dependent density functional theory (TD-DFT) and accounted for the contrasting features in the spectra. TD-DFT modeled the photochemical activity of both the optically dark π1σ∗ states (dissociative) and optically bright π1π∗ states well, predicting the barrierless deactivation of the B12 (ππ ∗) state of pyrrole and the bound minimum of the B12 (ππ ∗) state in 2,5-dimethylpyrrole. However, the quantitative agreement between vibronic

  15. Palladium-Catalyzed Dynamic Kinetic Asymmetric Transformations of Vinyl Aziridines with Nitrogen Heterocycles: Rapid Access to Biologically Active Pyrroles and Indoles

    PubMed Central

    Trost, Barry M.; Osipov, Maksim; Dong, Guangbin

    2010-01-01

    We report that nitrogen heterocycles can serve as competent nucleophiles in the palladium-catalyzed dynamic kinetic asymmetric alkylation of vinyl aziridines. The resulting alkylated products were obtained with high regio-, chemo-, and enantioselectivity. Both substituted 1H-pyrroles and 1H-indoles were successfully employed to give exclusively the branched N-alkylated products. The synthetic utility of this process was demonstrated by applying this method to the preparation of several medicinal chemistry lead compounds and bromopyrrole alkaloids including longamide B, longamide B methyl ester, hanishin, agesamides A and B, and cyclooroidin. PMID:20949972

  16. 2-[(1-Methyl-1H-pyrrol-2-yl)carbonyl­meth­yl]isoindoline-1,3-dione

    PubMed Central

    Schlosser, Joachim; Schollmeyer, Dieter; Laufer, Stefan; Peifer, Christian

    2009-01-01

    The asymmetric unit of the title compound, C15H12N2O3, contains two almost identical mol­ecules forming an nearly C 2-symmetric dimeric pattern. The dihedral angles between the pyrrole ring and the phthalimide unit are 82.95 (8) and 86.57 (8)° for the two mol­ecules. Within such a dimer, the phthalimide units of the two mol­ecules form a dihedral angle of 1.5 (5)°. PMID:21577840

  17. Structure and spectroscopic properties of N,S-coordinating 2-methyl­sulfanyl-N-[(1H-pyrrol-2-yl)methyl­idene]aniline methanol monosolvate

    PubMed Central

    Richards, D. Douglas; Ang, M. Trisha C.; McDonald, Robert; Bierenstiel, Matthias

    2015-01-01

    The reaction of pyrrole-2-carboxaldehyde and 2-(methyl­sulfan­yl)aniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding inter­actions link the aniline mol­ecule and a nearby methanol solvent mol­ecule. These units are linked by a pair of weak C—H⋯Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules. PMID:26594390

  18. Unexpected isocyanide-based three-component bicyclizations for stereoselective synthesis of densely functionalized pyrano[3,4-c]pyrroles

    PubMed Central

    Gao, Qian; Hao, Wen-Juan; Liu, Feng; Wang, Shu-Liang

    2015-01-01

    A novel three-component bicyclization strategy for efficient synthesis of densely functionalized pyrano[3,4-c]pyrroles has been established from readily accessible 3-aroylacrylic acids, dialkyl acetylenedicarboxylates and isocyanides. The reaction pathway involves Huisgen 1,3-dipole formation, Passerini-type reaction, Mumm rearrangement and oxo-Diels–Alder reaction sequence, resulting in continuous multiple bond-forming events including C–N, C–O and C–H bonds to rapidly build up molecular complexity. PMID:26576646

  19. Strikingly different luminescent properties arising from single crystals grown from solution or from the vapor phase in a diketo-pyrrolo-pyrrole analog

    NASA Astrophysics Data System (ADS)

    Imoda, Tomohiko; Mizuguchi, Jin

    2007-10-01

    The title compound di-cyano-pyrrolo-pyrrole (DCPP) is an analog of diketo-pyrrolo-pyrrole (DPP) known as a red pigment on the market. Brilliant orange photoluminescence has been observed in crystals of DCPP recrystallized from solution (crystal I); whereas the luminescence was quite weak in single crystals grown from the vapor phase (crystal II). To elucidate the difference in luminescent properties, a series of structural analysis together with thermal analysis has been carried out on crystals I and II at -180 °C, RT, 150 °C, and 200 °C. However, no difference in structure is recognized between crystals I and II within the precision of the x-ray analysis. Nevertheless, a slight difference in sublimation temperature of about 5° is observed between crystals I and II. Since the sublimation temperature depends on the cohesion in the solid state and the cohesion, in turn, governs the extent of lattice vibration (i.e., nonradiative process), a slight difference in sublimation temperature appears to determine the fraction between the radiative and nonradiative processes in crystals I and II.

  20. New pyrrole inhibitors of monoamine oxidase: synthesis, biological evaluation, and structural determinants of MAO-A and MAO-B selectivity.

    PubMed

    La Regina, Giuseppe; Silvestri, Romano; Artico, Marino; Lavecchia, Antonio; Novellino, Ettore; Befani, Olivia; Turini, Paola; Agostinelli, Enzo

    2007-03-01

    A series of new pyrrole derivatives have been synthesized and evaluated for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. N-Methyl,N-(benzyl),N-(pyrrol-2-ylmethyl)amine (7) and N-(2-benzyl),N-(1-methylpyrrol-2-ylmethyl)amine (18) were the most selective MAO-B (7, SI = 0.0057) and MAO-A (18, SI = 12500) inhibitors, respectively. Docking and molecular dynamics simulations gave structural insights into the MAO-A and MAO-B selectivity. Compound 18 forms an H-bond with Gln215 through its protonated amino group into the MAO-A binding site. This H-bond is absent in the 7/MAO-A complex. In contrast, compound 7 places its phenyl ring into an aromatic cage of the MAO-B binding pocket, where it forms charge-transfer interactions. The slightly different binding pose of 18 into the MAO-B active site seems to be forced by a bulkier Tyr residue, which replaces a smaller Ile residue present in MAO-A. PMID:17256833

  1. A new titanium biofunctionalized interface based on poly(pyrrole-3-acetic acid) coating: proliferation of osteoblast-like cells and future perspectives.

    PubMed

    De Giglio, Elvira; Cometa, Stefania; Calvano, Cosima-Damiana; Sabbatini, Luigia; Zambonin, Pier Giorgio; Colucci, Silvia; Benedetto, Adriana Di; Colaianni, Graziana

    2007-09-01

    In recent years, many procedures based on surface modification have been suggested to improve the biocompatibility and biofunctionality of orthopedic titanium-based implants. In this contest, the development of a new titanium-based biomaterial that could be covalently modified with biologically active molecules (i.e., RGD-peptides, growth factors, etc.) able to improve osteoblasts response was investigated. The strategy followed was based on a preliminary coating of the implant material by an adherent thin polymer film to which bioactive molecules could be grafted exploiting the polymer surface chemical reactivity. In this work, we focused our attention on pyrrole-3-acetic acid (Py-3-acetic), a pyrrole with carboxylic acid substituent, whose electrosynthesis and characterization on titanium substrates were already accomplished and whose potentialities in the design of new biocompatible surfaces are well evident. As first step, the biocompatibility of the electrochemically grown PPy-3-acetic films was investigated performing in vitro tests (adhesion and proliferation) with mouse bone marrow cells. Successively, the availability and reactivity of surface carboxylic groups were tested through the grafting of an aminoacidic residue to PPy-3-acetic films. PMID:17483896

  2. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B 2 : Catalytic Polymerisation of Aniline and Pyrrole

    DOE PAGESBeta

    Nadagouda, Mallikarjuna N.; Varma, Rajender S.

    2008-01-01

    Formore » the first time, we report green chemistry approach using vitamin B 2 in the synthesis of silver (Ag) and palladium (Pd), nanospheres, nanowires, and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride ( NaBH 4 ) or hydroxylamine hydrochloride and any special capping or dispersing agent. Vitamin B 2 was used as reducing agent as well as capping agent due to its high-water solubility, biodegradability, and low-toxicity compared with other reducing agents. The average particle size of nanoprticle was found to be Ag (average size 6.1 ± 0.1 nm) and Pd (average size 4.1 ± 0.1 nm) nanoparticles in ethylene glycol and Ag (average size 5.9 ± 0.1 nm, and average size 6.1 ± 0.1) nanoparticles in acetic acid and NMP, respectively. The formation of noble multiple shape nanostructures and their self assembly were dependent on the solvent employed for the preparation. When water was used as solvent media, Ag and Pd nanoparticles started to self-assemble into rod-like structures and in isopropanol Ag and Pd nanoparticles yielded wire-like structures with a thickness in the range of 10 to 20 nm and several hundred microns in length. In acetone and acetonitrile medium, the Ag and Pd nanoparticles are self-assembled into a regular pattern making nanorod structures with thicknesses ranging from 100 to 200 nm and lengths of a few microns. The so-synthesized nanostructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, and UV spectroscopy. The ensuing Ag and Pd nanoparticles catalyzed the reactions of aniline and pyrrole to generate polyaniline and polypyrrole nanofibers and may find various technological and biological applications. This single-step greener approach is general and can be extended to other noble metals and transition metal oxides.« less

  3. ITN Mixtures of Chlorfenapyr (Pyrrole) and Alphacypermethrin (Pyrethroid) for Control of Pyrethroid Resistant Anopheles arabiensis and Culex quinquefasciatus

    PubMed Central

    Oxborough, Richard M.; Kitau, Jovin; Matowo, Johnson; Feston, Emmanuel; Mndeme, Rajab; Mosha, Franklin W.; Rowland, Mark W.

    2013-01-01

    Pyrethroid resistant Anopheles gambiae malaria vectors are widespread throughout sub-Saharan Africa and continued efficacy of pyrethroid ITNs is under threat. Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action conferring no cross-resistance to existing public health insecticides. Mixtures of chlorfenapyr (CFP) and alphacypermethrin (alpha) may provide additional benefits over chlorfenapyr or alphacypermethrin used alone. An ITN mixture of CFP 100 mg/m2+alpha 25 mg/m2 was compared with CFP 100 mg/m2 and alpha 25 mg/m2 in a small-scale experimental hut trial in an area of wild An. arabiensis. The same treatments were evaluated in tunnel tests against insectary-reared pyrethroid susceptible and resistant Culex quinquefasciatus. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Tunnel tests showed that mixtures of CFP 100+ alpha 25 were 1.2 and 1.5 times more effective at killing susceptible Cx. quinquefasciatus than either Alpha 25 (P = 0.001) or CFP 100 (P = 0.001) ITNs. Mixtures of CFP100+ alpha 25 were 2.2 and 1.2 times more effective against resistant Cx. quinquefasciatus than either alpha 25 (P = 0.001) or CFP100 (P = 0.003) ITNs. CFP 100+ alpha 25 produced higher levels of blood-feeding inhibition than CFP alone for susceptible (94 vs 46%, P = 0.001) and resistant (84 vs 53%, P = 0.001) strains. In experimental huts the mixture of CFP 100+ Alpha 25 killed 58% of An. arabiensis, compared with 50% for alpha and 49% for CFP, though the differences were not significant. Blood-feeding inhibition was highest in the mixture with a 76% reduction compared to the untreated net (P = 0.001). ITN mixtures of chlorfenapyr and alphacypermethrin should restore effective control of resistant populations of An. gambiae malaria vectors, provide protection from blood-feeding, and may have benefits for resistance management, particularly in areas with low or moderate frequency

  4. Pyrrole-imidazole polyamide-mediated silencing of KCNQ1OT1 expression induces cell death in Wilms' tumor cells.

    PubMed

    Yoshizawa, Shinsuke; Fujiwara, Kyoko; Sugito, Kiminobu; Uekusa, Shota; Kawashima, Hiroyuki; Hoshi, Reina; Watanabe, Yosuke; Hirano, Takayuki; Furuya, Takeshi; Masuko, Takayuki; Ueno, Takahiro; Fukuda, Noboru; Soma, Masayoshi; Ozaki, Toshinori; Koshinaga, Tsugumichi; Nagase, Hiroki

    2015-07-01

    KvDMR (an intronic CpG island within the KCNQ1 gene) is one of the imprinting control regions on human chromosome 11p15.5. Since KvDMR exists within the promoter region of KCNQ1OT1 (antisense transcript of KCNQ1), it is likely that genomic alterations of this region including deletion, paternal uniparental disomy and de-methylation in maternal allele lead to aberrant overexpression of KCNQ1OT1. Indeed, de-methylation of KvDMR accompanied by uncontrolled overexpression of KCNQ1OT1 occurs frequently in Beckwith-Wiedemann syndrome (BWS), and around 10% of BWS patients developed embryonal tumors (Wilms' tumor or hepatoblastoma). These observations strongly suggest that silencing of KCNQ1OT1 expression might suppress its oncogenic potential. In the present study, we designed two pyrrole-imidazole (PI) polyamides, termed PI-a and PI-b, which might have the ability to bind to CCAAT boxes of the KCNQ1OT1 promoter region, and investigated their possible antitumor effect on Wilms' tumor-derived G401 cells. Gel retardation assay demonstrated that PI-a and PI-b specifically bind to their target sequences. Microscopic observations showed the efficient nuclear access of these PI polyamides. Quantitative real-time PCR analysis revealed that the expression level of KCNQ1OT1 was significantly decreased when treated with PI-a and PI-b simultaneously but not with either PI-a or PI-b single treatment. Consistent with these results, the combination of PI-a and PI-b resulted in a significant reduction in viability of G401 cells in a dose-dependent manner. Furthermore, FACS analysis demonstrated that combinatory treatment with PI-a and PI-b induces cell death as compared with control cells. Taken together, our present observations strongly suggest that the combinatory treatment with PI polyamides targeting KCNQ1OT1 might be a novel therapeutic strategy to cure patients with tumors over-expressing KCNQ1OT1. PMID:25998555

  5. Bicyclic octahydrocyclohepta[b]pyrrol-4(1H)one derivatives as novel selective anti-hepatitis C virus agents.

    PubMed

    Kaushik-Basu, Neerja; Ratmanova, Nina K; Manvar, Dinesh; Belov, Dmitry S; Cevik, Ozge; Basu, Amartya; Yerukhimovich, Mark M; Lukyanenko, Evgeny R; Andreev, Ivan A; Belov, Grigory M; Manfroni, Giuseppe; Cecchetti, Violetta; Frick, David N; Kurkin, Alexander V; Altieri, Andrea; Barreca, Maria Letizia

    2016-10-21

    We report the discovery of the bicyclic octahydrocyclohepta[b]pyrrol-4(1H)-one scaffold as a new chemotype with anti-HCV activity on genotype 1b and 2a subgenomic replicons. The most potent compound 34 displayed EC50 values of 1.8 μM and 4.5 μM in genotype 1b and 2a, respectively, coupled with the absence of any antimetabolic effect (gt 1b SI = 112.4; gt 2a SI = 44.2) in a cell-based assay. Compound 34 did not target HCV NS5B, IRES, NS3 helicase, or selected host factors, and thus future work will involve the unique mechanism of action of these new antiviral compounds. PMID:27376494

  6. Spectral, IR and magnetic studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with pyrrole-2-carboxyaldehyde thiosemicarbazone (L)

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Kumar, Anil

    2007-11-01

    Mn(II), Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L) derived from pyrrole-2-carboxyaldehyde. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurement, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO indicates that the complexes are non-electrolyte except Co(L) 2(NO 3) 2 and Ni(L) 2(NO 3) 2 complexes which are 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Mn(II), Co(II) and Ni(II) complexes except Co(L) 2(NO 3) 2 and Ni(L) 2(NO 3) 2 which are of tetrahedral geometry. A tetragonal geometry may be suggested for Cu(II) complexes.

  7. Preparation and evaluation of composites from montmorillonite and some heterocyclic polymers: 3. A water dispersible nanocomposite from pyrrole-montmorillonite polymerization system

    SciTech Connect

    SinhaRay, S.; Biswas, M.

    1999-06-01

    Montmorillonite (MMT)-based nanocomposites of polypyrrole (PPY) were prepared through the polymerization of pyrrole with MMT and FeCl{sub 3}-impregnated MM in bulk and in aqueous medium. The composites were characterized by IR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) studies. XRD analyses revealed no change in d{sub 001} spacing in MMT (9.8 {angstrom}), suggesting no intercalation of PPY into MMT lamellae. TEM analysis indicated the particle size to be 25 {+-} 7 nm. The bulk conductivity of the composites was in the range of (1.3 to 26) x 10{sup {minus}5} S/cm, depending on the FeCl{sub 3}-impregnation level and on the PPY loading in the composites. Suitable procedures were developed for obtaining a stable aqueous dispersion and a reversible dispersion of these composites.

  8. Low-cost synthesis and physical characterization of thieno[3,4-c]pyrrole-4,6-dione-based polymers.

    PubMed

    Berrouard, Philippe; Dufresne, Stéphane; Pron, Agnieszka; Veilleux, Justine; Leclerc, Mario

    2012-09-21

    The improved synthesis of thieno[3,4-c]pyrrole-4,6-dione (TPD) monomers, including Gewald thiophene ring formation, a Sandmeyer-type reaction, and neat condensation with an amine, is presented. This protocol enables faster, cheaper, and more efficient preparation of TPD units in comparison to traditional methods. Furthermore, a series of TPD homo- and pseudohomopolymers bearing various alkyl chains was synthesized via a direct heteroarylation polymerization (DHAP) procedure. UV-visible absorption and powder X-ray diffraction measurements revealed the relationship between the ratio of branched to linear alkyl chains and the optoelectronic properties of the polymers as well as their packing in the solid state. PMID:22946845

  9. Discovery of novel Tetrahydrobenzo[b]thiophene and pyrrole based scaffolds as potent and selective CB2 receptor ligands: The structural elements controlling binding affinity, selectivity and functionality.

    PubMed

    Osman, Noha A; Ligresti, Alessia; Klein, Christian D; Allarà, Marco; Rabbito, Alessandro; Di Marzo, Vincenzo; Abouzid, Khaled A; Abadi, Ashraf H

    2016-10-21

    CB2-based therapeutics show strong potential in the treatment of diverse diseases such as inflammation, multiple sclerosis, pain, immune-related disorders, osteoporosis and cancer, without eliciting the typical neurobehavioral side effects of CB1 ligands. For this reason, research activities are currently directed towards the development of CB2 selective ligands. Herein, the synthesis of novel heterocyclic-based CB2 selective compounds is reported. A set of 2,5-dialkyl-1-phenyl-1H-pyrrole-3-carboxamides, 5-subtituted-2-(acylamino)/(2-sulphonylamino)-thiophene-3-carboxylates and 2-(acylamino)/(2-sulphonylamino)-tetrahydrobenzo[b]thiophene-3-carboxylates were synthesized. Biological results revealed compounds with remarkably high CB2 binding affinity and CB2/CB1 subtype selectivity. Compound 19a and 19b from the pyrrole series exhibited the highest CB2 receptor affinity (Ki = 7.59 and 6.15 nM, respectively), as well as the highest CB2/CB1 subtype selectivity (∼70 and ∼200-fold, respectively). In addition, compound 6b from the tetrahydrobenzo[b]thiophene series presented the most potent and selective CB2 ligand in this series (Ki = 2.15 nM and CB2 subtype selectivity of almost 500-fold over CB1). Compound 6b showed a full agonism, while compounds 19a and 19b acted as inverse agonists when tested in an adenylate cyclase assay. The present findings thus pave the way to the design and optimization of heterocyclic-based scaffolds with lipophilic carboxamide and/or retroamide substituent that can be exploited as potential CB2 receptor activity modulators. PMID:27448919

  10. Anchoring the Gas-Phase Acidity Scale from Hydrogen Sulfide to Pyrrole. Experimental Bond Dissociation Energies of Nitromethane, Ethanethiol, and Cyclopentadiene.

    PubMed

    Ervin, Kent M; Nickel, Alex A; Lanorio, Jerry G; Ghale, Surja B

    2015-07-16

    A meta-analysis of experimental information from a variety of sources is combined with statistical thermodynamics calculations to refine the gas-phase acidity scale from hydrogen sulfide to pyrrole. The absolute acidities of hydrogen sulfide, methanethiol, and pyrrole are evaluated from literature R-H bond energies and radical electron affinities to anchor the scale. Relative acidities from proton-transfer equilibrium experiments are used in a local thermochemical network optimized by least-squares analysis to obtain absolute acidities of 14 additional acids in the region. Thermal enthalpy and entropy corrections are applied using molecular parameters from density functional theory, with explicit calculation of hindered rotor energy levels for torsional modes. The analysis reduces the uncertainties of the absolute acidities of the 14 acids to within ±1.2 to ±3.3 kJ/mol, expressed as estimates of the 95% confidence level. The experimental gas-phase acidities are compared with calculations, with generally good agreement. For nitromethane, ethanethiol, and cyclopentadiene, the refined acidities can be combined with electron affinities of the corresponding radicals from photoelectron spectroscopy to obtain improved values of the C-H or S-H bond dissociation energies, yielding D298(H-CH2NO2) = 423.5 ± 2.2 kJ mol(-1), D298(C2H5S-H) = 364.7 ± 2.2 kJ mol(-1), and D298(C5H5-H) = 347.4 ± 2.2 kJ mol(-1). These values represent the best-available experimental bond dissociation energies for these species. PMID:25549109

  11. Design, synthesis, and SAR of new pyrrole-oxindole progesterone receptor modulators leading to 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-1-methyl-1H-pyrrole-2-carbonitrile (WAY-255348).

    PubMed

    Fensome, Andrew; Adams, William R; Adams, Andrea L; Berrodin, Tom J; Cohen, Jeff; Huselton, Christine; Illenberger, Arthur; Kern, Jeffrey C; Hudak, Valerie A; Marella, Michael A; Melenski, Edward G; McComas, Casey C; Mugford, Cheryl A; Slayden, Ov D; Yudt, Matthew; Zhang, Zhiming; Zhang, Puwen; Zhu, Yuan; Winneker, Richard C; Wrobel, Jay E

    2008-03-27

    We have continued to explore the 3,3-dialkyl-5-aryloxindole series of progesterone receptor (PR) modulators looking for new agents to be used in female healthcare: contraception, fibroids, endometriosis, and certain breast cancers. Previously we reported that subtle structural changes with this and related templates produced functional switches between agonist and antagonist properties ( Fensome et al. Biorg. Med. Chem. Lett. 2002, 12, 3487; 2003, 13, 1317 ). We herein report a new functional switch within the 5-(2-oxoindolin-5-yl)-1 H-pyrrole-2-carbonitrile class of compounds. We found that the size of the 3,3-dialkyl substituent is important for controlling the functional response; thus small groups (dimethyl) afford potent PR antagonists, whereas larger groups (spirocyclohexyl) are PR agonists. The product from our optimization activities in cell-based systems and also for kinetic properties in rodents and nonhuman primates was 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1 H-indol-5-yl)-1-methyl-1 H-pyrrole-2-carbonitrile 27 (WAY-255348), which demonstrated potent and robust activity on PR antagonist and contraceptive end points in the rat and also in cynomolgus and rhesus monkeys including ovulation inhibition, menses induction, and reproductive tract morphology. PMID:18318463

  12. Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin.

    PubMed

    Gill, Iqbal; Patel, Ramesh

    2006-02-01

    An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%. PMID:16257208

  13. Ferrocene-functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: a novel design in conducting polymer-based electrochemical biosensors.

    PubMed

    Ayranci, Rukiye; Demirkol, Dilek Odaci; Ak, Metin; Timur, Suna

    2015-01-01

    Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method. PMID:25591169

  14. Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

    PubMed Central

    Ayranci, Rukiye; Demirkol, Dilek Odaci; Ak, Metin; Timur, Suna

    2015-01-01

    Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method. PMID:25591169

  15. Spectroscopic characterization and biological activity of Zn(II), Cd(II), Sn(II) and Pb(II) complexes with Schiff base derived from pyrrole-2-carboxaldehyde and 2-amino phenol

    NASA Astrophysics Data System (ADS)

    Singh, Bibhesh K.; Prakash, Anant; Rajour, Hemant K.; Bhojak, Narendar; Adhikari, Devjani

    2010-08-01

    A new Schiff base 2-aminophenol-pyrrole-2-carboxaldehyde and its Zn(II), Cd(II), Sn(II) and Pb(II) complexes have been synthesized and characterized by various physicochemical studies. Spectral studies (IR and 1H NMR) indicate deprotonation and coordination of phenolic oxygen along with binding of pyrrole nitrogen, azomethine nitrogen and anion with metal ions. The presence of lattice water molecule(s) has also been confirmed by TG/DTA studies. Mass spectrum explains the successive degradation of the molecular species in solution and justifies ML complexes. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redfern method, which confirm first order kinetics. The bio-efficacy of the ligand and their complexes has been examined against the growth of bacteria in vitro to evaluate their antimicrobial potential. Molecular structures of the complexes have been optimized by MM2 calculations and suggest a tetrahedral geometry around metal ions.

  16. 4-Dimethyl­amino-1-(4-meth­oxy­phen­yl)-2,5-dioxo-2,5-dihydro-1H-pyrrole-3-carbonitrile

    PubMed Central

    Abdel-Wahab, Bakr F.; Mohamed, Hanan A.; Farahat, Abdelbasset A.; Ng, Seik Weng; Tiekink, Edward R. T.

    2013-01-01

    In the title compound, C14H13N3O3, a twist occurs, as seen in the dihedral angle of 53.60 (12)° between the pyrrole and benzene rings. A three-dimensional architecture is formed in the crystal whereby layers of mol­ecules in the ac plane are connected by C—H⋯O and C—H⋯π inter­actions. PMID:23476607

  17. Thieno[3,2-b]- and thieno[2,3-b]pyrrole bioisosteric analogues of the hallucinogen and serotonin agonist N,N-dimethyltryptamine.

    PubMed

    Blair, J B; Marona-Lewicka, D; Kanthasamy, A; Lucaites, V L; Nelson, D L; Nichols, D E

    1999-03-25

    The synthesis and biological activity of 6-[2-(N, N-dimethylamino)ethyl]-4H-thieno[3,2-b]pyrrole (3a) and 4-[2-(N, N-dimethylamino)ethyl]-6H-thieno[2,3-b]pyrrole (3b), thienopyrroles as potential bioisosteres of N,N-dimethyltryptamine (1a), are reported. Hallucinogen-like activity was evaluated in the two-lever drug discrimination paradigm using LSD- and DOI-trained rats. Neither 3a nor 3b substituted for LSD or DOI up to doses of 50 micromol/kg. By comparison, 1a fully substituted in LSD-trained rats. However, 3a and 3b fully substituted for the 5-HT1A agonist LY293284 ((-)-(4R)-6-acetyl-4-(di-n-propylamino)-1,3,4, 5-tetrahydrobenz[c,d]indole). Both 3a and 3b induced a brief "serotonin syndrome" and salivation, an indication of 5-HT1A receptor activation. At the cloned human 5-HT2A receptor 3b had about twice the affinity of 3a. At the cloned human 5-HT2B and 5-HT2C receptors, however, 3a had about twice the affinity of 3b. Therefore, thiophene lacks equivalence as a replacement for the phenyl ring in the indole nucleus of tryptamines that bind to 5-HT2 receptor subtypes and possess LSD-like behavioral effects. Whereas both of the thienopyrroles had lower affinity than the corresponding 1a at 5-HT2 receptors, 3a and 3b had significantly greater affinity than 1a at the 5-HT1A receptor. Thus, thienopyrrole does appear to serve as a potent bioisostere for the indole nucleus in compounds that bind to the serotonin 5-HT1A receptor. These differences in biological activity suggest that serotonin receptor isoforms are very sensitive to subtle changes in the electronic character of the aromatic systems of indole compounds. PMID:10090793

  18. Synthesis and spectroscopic characterization on 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid: A DFT approach

    NASA Astrophysics Data System (ADS)

    Kurt, M.; Sas, E. Babur; Can, M.; Okur, S.; Icli, S.; Demic, S.; Karabacak, M.; Jayavarthanan, T.; Sundaraganesan, N.

    2016-01-01

    A complete structural and vibrational analysis of the 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid (TPBA), was carried out by ab initio calculations, at the density functional theory (DFT) method. Molecular geometry, vibrational wavenumbers and gauge including atomic orbital (GIAO) 13C NMR and 1H NMR chemical shift values of (TPBA), in the ground state have been calculated by using ab initio density functional theory (DFT/B3LYP) method with 6-311G(d,p) as basis set for the first time. Comparison of the observed fundamental vibrational modes of (TPBA) and calculated results by DFT/B3LYP method indicates that B3LYP level of theory giving yield good results for quantum chemical studies. Vibrational wavenumbers obtained by the DFT/B3LYP method are in good agreement with the experimental data. The study was complemented with a natural bond orbital (NBO) analysis, to evaluate the significance of hyperconjugative interactions and electrostatic effects on such molecular structure. By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals analysis and thermodynamic properties of TPBA were investigated using theoretical calculations.

  19. Pyrrole-Terminated Ionic Liquid Surfactant: One Molecule with Multiple Functions for Controlled Synthesis of Diverse Multispecies Co-Doped Porous Hollow Carbon Spheres.

    PubMed

    Li, Jian; Zhu, Wei; Ji, Jingwei; Wang, Peng; Lan, Yue; Gao, Ning; Yin, Xianpeng; Wang, Hui; Li, Guangtao

    2016-05-01

    Rationally and efficiently controlling chemical composition, microstructure, and morphology of carbon nanomaterials plays a crucial role in significantly enhancing their functional properties and expending their applications. In this work, a novel strategy for simultaneously controlling these structural parameters was developed on the base of a multifunctional precursor approach, in which the precursor not only serves as carbon source and structure-directing agent, but also contains two heteroatom doping sites. As exemplified by using pyrrole-terminated ionic liquid surfactant as such precursor, in conjunction with sol-gel chemistry this strategy allows for efficiently producing well-defined hollow carbon spheres with controlled microstructure and chemical compositions. Remarkably, the dual-doping sites in confined silica channels provide an exciting opportunity and flexibility to access various doped carbons through simply anion exchange or altering the used oxidative polymerization agent, especially the multispecies codoped materials by combination of the two doping modes. All the results indicate that the described strategy may open up a new avenue for efficiently synthesizing functional carbon materials with highly controllable capability. PMID:27093191

  20. Design, synthesis and biological evaluation of 4-fluoropyrrolidine-2-carbonitrile and octahydrocyclopenta[b]pyrrole-2-carbonitrile derivatives as dipeptidyl peptidase IV inhibitors.

    PubMed

    Ji, Xun; Xia, Chunmei; Wang, Jiang; Su, Mingbo; Zhang, Lei; Dong, Tiancheng; Li, Zeng; Wan, Xia; Li, Jingya; Li, Jia; Zhao, Linxiang; Gao, Zhaobing; Jiang, Hualiang; Liu, Hong

    2014-10-30

    Based on the previous work in our group and the principle of computer-aided drug design, a series of novel β-amino pyrrole-2-carbonitrile derivatives was designed and synthesized. Compounds 8l and 9l were efficacious and selective DPP4 inhibitors resulting in decreased blood glucose in vivo. Compound 8l had moderate DPP4 inhibitory activity (IC50 = 0.05 μM) and good oral bioavailability (F = 53.2%). Compound 9l showed excellent DPP4 inhibitory activity (IC50 = 0.01 μM), good selectivity (selective ratio: DPP8/DPP4 = 898.00; DPP9/DPP4 = 566.00) against related peptidases, and good efficacy in an oral glucose tolerance tests in ICR mice and moderate PK profiles (F = 22.8%, t1/2 = 2.74 h). Moreover, compound 9l did not block hERG channel and exhibited no inhibition of liver metabolic enzymes such as CYP2C9. PMID:25164763

  1. [Determination of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry].

    PubMed

    Xu, Dunming; Lu, Shengyu; Chen, Dajie; Lan, Jinchang; Zhang, Zhigang; Yang, Fang; Zhou, Yu

    2013-03-01

    An effective method was developed and applied to determine the residues of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry (ASE-GC-MS/MS). The samples were extracted with ethyl acetate-hexane (1:1, v/v) for 5 min at 1.03 x 10(7) Pa and 100 degree C for one cycle. Then, they were purified by Envi-Carb/PSA column, and eluted by ethyl acetate-hexane (1:1, v/v). The analytes were determined by GC-MS/MS and quantified by external standard method. The limits of quantification were 0.003 mg/kg for fenpyroximate, 0.001 mg/kg for fipronil-sulfide, 0.002 mg/kg for fipronil, 0.005 mg/kg for fipronil-sulfone, 0.002 mg/kg for chlorfenapyr, 0.006 mg/kg for flusilazole, 0.001 mg/kg for difenzoquat, 0.001 mg/kg for pyraflufen-ethyl, 0.000 3 mg/kg for tebufenpyrad and 0.005 mg/kg for tolfenpyrad. The results show that the proposed method is sensitive and accurate for the determination of the ten pesticide residues. PMID:23785993

  2. Synthesis, molecular structure and spectral analysis of ethyl 4-formyl-3,5-dimethyl-1H-pyrrole-2-carboxylate thiosemicarbazone: A combined DFT and AIM approach

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Kumar, Amit; Tiwari, R. K.; Rawat, Poonam; Verma, Divya; Baboo, Vikas

    2012-05-01

    A new ethyl 4-formyl-3,5-dimethyl-1H-pyrrole-2-carboxylate thiosemicarbazone (EFDMPCT) has been synthesized and characterized by elemental analysis and FT-IR, 1H NMR, UV-Visible, DART-mass spectroscopy. Quantum chemical calculations have been performed by DFT level of theory using B3LYP functional and 6-31G (d,p) as basis set. The calculated 1H NMR chemical shifts using gauge including atomic orbitals (GIAO) approach are in good agreement with the observed chemical shifts. The electronic transitions within molecule have been interpreted using the time dependent density functional theory (TD-DFT). The calculated and experimental wavenumbers analyses confirm the existence of dimer. Topological parameters electron density, Laplacian of electron density, kinetic electron energy density, potential electron density and the total electron energy density at the bond critical points (BCP) analyzed using 'Atoms in Molecules' AIM theory reveals intra and inter molecular hydrogen bonding other weaker interactions in detail. The calculated intermolecular hydrogen bond energy of dimer is -12.2176 kcal/mol using AIM calculation. The results of AIM ellipticity confirm the existence of resonance assisted hydrogen bonds in dimer. The calculated thermodynamic parameters show that reaction is exothermic and non-spontaneous at room temperature. The local reactivity descriptors find the reactive sites within molecules have been calculated.

  3. Experimental and DFT study on a newly synthesized ethyl 2-cyano-3-[5-(phenyl-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-02-01

    A newly synthesized ethyl 2-cyano-3-[5-(phenyl-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate (ECPHPA) has been characterized by experimental measurements. The theoretically calculated results are in accordance with the experimental studies. All calculations have been performed using B3LY/6-31G(d,p) basis set. The oscillatory strength (f) and wavelength of various electronic excitations show π → π∗ nature of transitions. Natural bond orbital (NBO) analysis shows intramolecular conjugative/hyperconjugative interactions within the studied molecule. The result of hydrogen bonding is obvious in 1H NMR, FT-IR and NBO analyses as down field chemical shift, vibrational red shift and π1(C8sbnd N9) → σ∗(N1sbnd H24) interaction, respectively. Global electrophilicity index (ω = 4.80 eV) shows that ECPHPA is a strong electrophile and local reactivity descriptors indicate have reactive sites within molecule and undergo for the formation of various heterocyclic compounds. The first hyperpolarizability (β0) computed found to be 35.76 × 10-30 esu, evaluate the suitability of compound for non-linear optical (NLO) response.

  4. FT-IR, Laser-Raman spectra and quantum chemical calculations of methyl 4-(trifluoromethyl)-1H-pyrrole-3-carboxylate-A DFT approach

    NASA Astrophysics Data System (ADS)

    Sert, Yusuf; Sreenivasa, S.; Doğan, H.; Manojkumar, K. E.; Suchetan, P. A.; Ucun, Fatih

    2014-06-01

    In this study the experimental and theoretical vibrational frequencies of a newly synthesized anti-tumor and anti-inflammatory agent namely, methyl 4-(trifluoromethyl)-1H-pyrrole-3-carboxylate have been investigated. The experimental FT-IR (4000-400 cm-1) and Laser-Raman spectra (4000-100 cm-1) of the molecule in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths, bond angles and torsion angles) have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: highly parameterized, empirical exchange correlation function) with 6-311++G(d,p) basis set by Gaussian 03 software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated using the same theoretical calculations.

  5. Design, spectral characterization, DFT and biological studies of transition metal complexes of Schiff base derived from 2-aminobenzamide, pyrrole and furan aldehyde

    NASA Astrophysics Data System (ADS)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.; Sharma, Deepansh

    2015-05-01

    A series of two biologically active Schiff base ligands L1, L2 have been synthesized in equimolar reaction of 2-aminobenzamide with pyrrol-2-carboxaldehyde and furan-2-carboxaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 2:1. The characterization of newly formed complexes was done by 1H NMR, UV-Vis, TGA, IR, mass spectrophotometry, EPR and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes and distorted octahedral geometry for Cu(II) complexes. All the synthesized compounds, were studied for their in vitro antimicrobial activities, against four bacterial strains and two fungal strains by using serial dilution method. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

  6. Highly stable water dispersible calix[4]pyrrole octa-hydrazide protected gold nanoparticles as colorimetric and fluorometric chemosensors for selective signaling of Co(II) ions

    NASA Astrophysics Data System (ADS)

    Bhatt, Keyur D.; Vyas, Disha J.; Makwana, Bharat A.; Darjee, Savan M.; Jain, Vinod K.

    2014-03-01

    Water dispersible stable gold nanoparticles (AuNps) have been synthesized by using calix[4]pyrrole octa-hydrazide (CPOH) as a reducing as well as stabilizing agent. CPOH-AuNps have been characterized by surface plasmon resonance, particle size analyzer and transmission electron microscopy. CPOH-AuNps are water dispersible, highly stable for more than 150 days at neutral pH with a size of less than 10 nm and zeta potential of 15 ± 2 MeV. Ion sensing property of CPOH-AuNps has been investigated for various metal ions Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II), Co(II) and Cu(II) by colorimetry and spectrofluorimetry. Among all the metal ions investigated, only Co(II) ions gives sharp colour change from ruby red to blue and is easily detectable by naked-eye. CPOH-AuNps being fluorescent in nature also shows great sensitivity and selectivity for Co(II) ions. Co(II) ions can be selectively detected at very low concentration level of 1 nM in a facile way of fluorescence quenching.

  7. Design, spectral characterization, DFT and biological studies of transition metal complexes of Schiff base derived from 2-aminobenzamide, pyrrole and furan aldehyde.

    PubMed

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Sharma, Deepansh

    2015-05-15

    A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 2-aminobenzamide with pyrrol-2-carboxaldehyde and furan-2-carboxaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 2:1. The characterization of newly formed complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrophotometry, EPR and molar conductivity studies. The thermal studies suggested that the complexes are more stable as compared to ligand. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes and distorted octahedral geometry for Cu(II) complexes. All the synthesized compounds, were studied for their in vitro antimicrobial activities, against four bacterial strains and two fungal strains by using serial dilution method. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination. PMID:25706679

  8. Vibrational spectra and electronic structure of 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol - A computational insight on antioxidant active Mannich base

    NASA Astrophysics Data System (ADS)

    Boobalan, Maria susai; Tamilvendan, D.; Amaladasan, M.; Ramalingam, S.; Venkatesa Prabhu, G.; Bououdina, M.

    2015-02-01

    The 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol (IFTN) is a class of synthesized organic Mannich base compound having antioxidant property of biological importance. A meticulous normal mode vibrational analysis has been carried out by comparing and contrasting the experimentally recorded FT-IR and FT-Raman spectra with simulated spectra of IFTN. Similarly the calculated 1H and 13C NMR of IFTN were correlated with experimental findings to understand the shielding and deshielding nature hold in it. The following other electronic structure properties were calculated such as equilibrium geometrical parameters, natural bond orbital analysis (NBO), frontier molecular orbital (FMO) characterization, statistical thermochemical properties against a range of temperatures and molecular electrostatic potential (MEP) imprint was carried out along with various charges such as APT, ESP, Hirshfeld, natural and Mulliken. All these predicted properties unlock the nature of total behavior of IFTN in various dimensions. These could be Lewis, non-Lewis interaction along with their respective energies, contribution of fragmented moieties for various orders of HOMO and LUMO, temperature consequences on enthalpy, entropy, and heat capacity. In addition, the MEP leads to find electrophilic, nucleophilic reactive sites on IFTN molecular surface. The entire computational calculations has been made on HF/6-31+G/6-311++G(d,p) and B3LYP/6-31+G/6-311++G(d,p) model chemistries. A complete electronic structure observation has been achieved by this theoretical analysis.

  9. Synthesis and characterization of reduced graphene oxide supported gold nanoparticles-poly(pyrrole-co-pyrrolepropylic acid) nanocomposite-based electrochemical biosensor.

    PubMed

    Puri, Nidhi; Niazi, Asad; Srivastava, Avanish K; Rajesh

    2014-10-01

    A conducting poly(pyrrole-co-pyrrolepropylic acid) copolymer nanocomposite film (AuNP-PPy-PPa) incorporating gold nanoparticles (AuNP) was electrochemically grown using a single step procedure over electrochemically reduced graphene oxide (RGO) flakes deposited on a silane-modified indium-tin-oxide (ITO) glass plate. The RGO support base provided excellent mechanical and chemical stability to the polymer nanocomposite matrix. The porous nanostructure of AuNP-PPy-PPa/RGO provided a huge accessible area to disperse AuNP, and it avoided metallic agglomeration within the polymer matrix. The AuNP-PPy-PPa/RGO was characterized by high-resolution transmission electron microscopy (HRTEM), contact angle measurements, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The pendant carboxyl group of AuNP-PPy-PPa/RGO was covalently bonded with myoglobin protein antibody, Ab-Mb, for the construction of a bioelectrode. Electrochemical impedance spectroscopy technique was used for the characterization of the bioelectrode and as an impedimetric biosensor for the detection of human cardiac biomarker, Ag-cMb. The bioelectrode exhibited a linear impedimetric response to Ag-cMb in the range of 10 ng mL(-1) to 1 μg mL(-1), in phosphate-buffered solution (PBS) (pH 7.4, 0.1 M KCl) with a sensitivity of 92.13 Ω cm(2) per decade. PMID:24928550

  10. (1R*,2S*)-N,N′-Bis[(E)-1H-pyrrol-2-yl­methyl­idene]cyclo­hexane-1,2-diamine monohydrate

    PubMed Central

    Akerman, Kate J.

    2012-01-01

    The title compound, C16H20N4·H2O, was synthesized from cis-1,2-diamino­cyclo­hexane (a racemic mixture of the (1R,2S) and (1S,2R) enanti­omers). The compound crystallized with two mol­ecules (A and B) in the asymmetric unit with a single water solvent mol­ecule per Schiff base mol­ecule. Mol­ecules A and B have similar conformations as illustrated by the least-squares-fit with an r.m.s. deviation of 0.242 Å. The mol­ecules within the asymmetric unit are bridged by hydrogen bonds to the two water mol­ecules, resulting in a heterotetramer. The water mol­ecule acts as both a hydrogen-bond donor and acceptor. The pyrrole-imine units are not co-planar, making an angle of 73.9 (3)° and 76.9 (3)° in mol­ecules A and B, respectively. PMID:23476190

  11. The kinetics of complex formation in the trithiadiazoletri[3,4-di(4- tert-butylphenyl)-pyrrole] macrocycle-copper(II) acetate-DMFA-H2O system

    NASA Astrophysics Data System (ADS)

    Lomova, T. N.; Mozhzhukhina, E. G.; Danilova, E. A.; Islyaikin, M. K.

    2009-10-01

    The paper presents the results of a study of the kinetics of coordination of a macroheterocyclic compound with an increased coordination cavity of the (3 + 3) McH3 composition consisting of sequentially alternating 1,3,4-thiadiazole and 3,4-bis(4- tert-butylphenyl)pyrrole fragments to dehydrated Cu(OAc)2 in dimethylformamide with and without H2O admixtures. The reaction could be controlled spectrophotometrically over the salt and ligand concentration ranges (0.175-0.55) × 10-4 and (0.16-0.64) × 10-5 mol/l, respectively, at temperatures of 288-303 K. A kinetic equation of an unusual form with a negative order with respect to the salt was for the first time obtained experimentally for a macrocyclic ligand by the method of excess concentrations. The kinetics of the complex formation reaction was given a theoretical interpretation. Quantitative characteristics were obtained, and the role played by water in the kinetics of complex formation was studied. These data were of importance for practical applications, for the development of optimum conditions increasing the yield of complexes when they were synthesized in complex formation reactions.

  12. 4-Acyl Pyrrole Derivatives Yield Novel Vectors for Designing Inhibitors of the Acetyl-Lysine Recognition Site of BRD4(1).

    PubMed

    Hügle, Martin; Lucas, Xavier; Weitzel, Gerhard; Ostrovskyi, Dmytro; Breit, Bernhard; Gerhardt, Stefan; Einsle, Oliver; Günther, Stefan; Wohlwend, Daniel

    2016-02-25

    Several human diseases, including cancer, show altered signaling pathways resulting from changes in the activity levels of epigenetic modulators. In the past few years, small-molecule inhibitors against specific modulators, including the bromodomain and extra-terminal (BET) bromodomain family of acetylation readers, have shown early promise in the treatment of the genetically defined midline carcinoma and hematopoietic malignancies. We have recently developed a novel potent inhibitor of BET proteins, 1 (XD14[ Angew. Chem., Int. Ed. 2013, 52, 14055]), which exerts a strong inhibitory potential on the proliferation of specific leukemia cell lines. In the study presented here, we designed analogues of 1 to study the potential of substitutions on the 4-acyl pyrrole backbone to occupy additional sites within the substrate recognition site of BRD4(1). The compounds were profiled using ITC, DSF, and X-ray crystallography. We could introduce several substitutions that address previously untargeted areas of the substrate recognition site. This work may substantially contribute to the development of therapeutics with increased target specificity against BRD4-related malignancies. PMID:26731611

  13. Comparative Analysis of DNA-Binding Selectivity of Hairpin and Cyclic Pyrrole-Imidazole Polyamides Based on Next-Generation Sequencing.

    PubMed

    Kashiwazaki, Gengo; Chandran, Anandhakumar; Asamitsu, Sefan; Kawase, Takashi; Kawamoto, Yusuke; Sawatani, Yoshito; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

    2016-09-15

    Many long pyrrole-imidazole polyamides (PIPs) have been synthesized in the search for higher specificity, with the aim of realizing the great potential of such compounds in biological and clinical areas. Among several types of PIPs, we designed and synthesized hairpin and cyclic PIPs targeting identical sequences. Bind-n-Seq analysis revealed that both bound to the intended sequences. However, adenines in the data analyzed by the previously reported Bind-n-Seq method appeared to be significantly higher in the motif ratio than thymines, even though the PIPs were not expected to distinguish A from T. We therefore examined the experimental protocol and analysis pipeline in detail and developed a new method based on Bind-n-Seq motif identification with a reference sequence (Bind-n-Seq-MR). High-throughput sequence analysis of the PIP-enriched DNA data by Bind-n-Seq-MR presented A and T comparably. Surface plasmon resonance assays were performed to validate the new method. PMID:27387250

  14. Z-Shaped Pyrrolo[3,2-b]pyrroles and Their Transformation into π-Expanded Indolo[3,2-b]indoles.

    PubMed

    Stężycki, Rafał; Grzybowski, Marek; Clermont, Guillaume; Blanchard-Desce, Mireille; Gryko, Daniel T

    2016-04-01

    Sterically hindered 1,4-dihydropyrrolo[3,2-b]pyrroles possessing ortho-(arylethynyl)phenyl substituents at positions-2 and -5 were efficiently synthesized through a sila-Sonogashira reaction. These unique Z-shaped dyes showed relatively strong fluorescence in solution. Detailed optimization revealed that, in the presence of InCl3, these alkynes readily undergo an intramolecular double cyclization to give hexacyclic products bearing an indolo[3,2-b]indole skeleton in remarkable yields. Steady-state UV-visible spectroscopy revealed that upon photoexcitation, the prepared Z-shaped alkynes undergo mostly radiative relaxation leading to high fluorescence quantum yields. In the case of 7,14-dihydrobenzo[g]benzo[6,7]indolo[3,2-b]indoles, we believe that the substantial planarization of geometry in the excited state, is the underlying reason for the observed large Stokes shifts. The presence of additional electron-withdrawing groups makes it possible to further alter the photophysical properties. The two-photon absorption cross-section values of both families of dyes were found to be modest and the nature of the excited state responsible for two-photon absorption appeared to be strongly affected by the presence of peripheral groups. Serendipitous synthesis of unusual double-Z-shaped alkyne by Sonogashira and Glaser coupling is also reported. PMID:26889746

  15. Dendrimer Templated Synthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole Hydrogenation.

    SciTech Connect

    Huang, Wenyu; Kuhn, John N.; Tsung, Chia-Kuang; Zhang, Yawen; Habas, Susan E.; Yang, Peidong; Somorjai, Gabor A.

    2008-05-09

    Monodisperse rhodium (Rh) and platinum (Pt) nanoparticles as small as {approx}1 nm were synthesized within a fourth generation polyaminoamide (PAMAM) dendrimer, a hyperbranched polymer, in aqueous solution and immobilized by depositing onto a high-surface-area SBA-15 mesoporous support. X-ray photoelectron spectroscopy indicated that the as-synthesized Rh and Pt nanoparticles were mostly oxidized. Catalytic activity of the SBA-15 supported Rh and Pt nanoparticles was studied with ethylene hydrogenation at 273 and 293 K in 10 torr of ethylene and 100 torr of H{sub 2} after reduction (76 torr of H{sub 2} mixed with 690 torr of He) at different temperatures. Catalysts were active without removing the dendrimer capping but reached their highest activity after hydrogen reduction at a moderate temperature (423 K). When treated at a higher temperature (473, 573, and 673 K) in hydrogen, catalytic activity decreased. By using the same treatment that led to maximum ethylene hydrogenation activity, catalytic activity was also evaluated for pyrrole hydrogenation.

  16. Electrochromic properties of poly (1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole-co-3,4-ethylenedioxy thiophene) and its application in electrochromic devices

    NASA Astrophysics Data System (ADS)

    Tarkuc, S.; Sahmetlioglu, E.; Tanyeli, C.; Akhmedov, I. M.; Toppare, L.

    2008-06-01

    Electrochemical copolymerization of 1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole (PTP) with 3,4-ethylenedioxy thiophene (EDOT) was carried out in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple via potentiodynamic electrolysis. Characterizations of the resulting copolymer were performed via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and spectroelectrochemical analysis. Spectroelectrochemical analyses show that the copolymer of PTP with EDOT has an electronic band gap (due to π to π∗ transition) of 1.9 eV at 480 nm, with a claret red in the fully reduced form and a blue color in the fully oxidized form. Via kinetic studies, the optical contrast (ΔT %) was found to be 8% for P(PTP-co-EDOT). Results showed that the time required to reach 95% of the ultimate transmittance was 1.7 s for the copolymer. The P(PTP-co-EDOT) film was used to construct a dual type polymer electrochromic device (ECDs) with poly(3,4-ethylenedioxy thiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit memory of the device were investigated.

  17. Monocrotaline pyrrole-induced megalocytosis of lung and breast epithelial cells: Disruption of plasma membrane and Golgi dynamics and an enhanced unfolded protein response.

    PubMed

    Mukhopadhyay, Somshuvra; Shah, Mehul; Patel, Kirit; Sehgal, Pravin B

    2006-03-15

    The pyrrolizidine alkaloid monocrotaline (MCT) initiates pulmonary hypertension by inducing a "megalocytosis" phenotype in target pulmonary arterial endothelial, smooth muscle and Type II alveolar epithelial cells. In cultured endothelial cells, a single exposure to the pyrrolic derivative of monocrotaline (MCTP) results in large cells with enlarged endoplasmic reticulum (ER) and Golgi and increased vacuoles. However, these cells fail to enter mitosis. Largely based upon data from endothelial cells, we proposed earlier that a disruption of the trafficking and mitosis-sensor functions of the Golgi (the "Golgi blockade" hypothesis) may represent the subcellular mechanism leading to MCTP-induced megalocytosis. In the present study, we investigated the applicability of the Golgi blockade hypothesis to epithelial cells. MCTP induced marked megalocytosis in cultures of lung A549 and breast MCF-7 cells. This was associated with a change in the distribution of the cis-Golgi scaffolding protein GM130 from a discrete juxtanuclear localization to a circumnuclear distribution consistent with an anterograde block of GM130 trafficking to/through the Golgi. There was also a loss of plasma membrane caveolin-1 and E-cadherin, cortical actin together with a circumnuclear accumulation of clathrin heavy chain (CHC) and alpha-tubulin. Flotation analyses revealed losses/alterations in the association of caveolin-1, E-cadherin and CHC with raft microdomains. Moreover, megalocytosis was accompanied by an enhanced unfolded protein response (UPR) as evidenced by nuclear translocation of Ire1alpha and glucose regulated protein 58 (GRP58/ER-60/ERp57) and a circumnuclear accumulation of PERK kinase and protein disulfide isomerase (PDI). These data further support the hypothesis that an MCTP-induced Golgi blockade and enhanced UPR may represent the subcellular mechanism leading to enlargement of ER and Golgi and subsequent megalocytosis. PMID:16000202

  18. Monocrotaline pyrrole-induced megalocytosis of lung and breast epithelial cells: Disruption of plasma membrane and Golgi dynamics and an enhanced unfolded protein response

    SciTech Connect

    Mukhopadhyay, Somshuvra; Shah, Mehul; Patel, Kirit; Sehgal, Pravin B. . E-mail: pravin_sehgal@nymc.edu

    2006-03-15

    The pyrrolizidine alkaloid monocrotaline (MCT) initiates pulmonary hypertension by inducing a 'megalocytosis' phenotype in target pulmonary arterial endothelial, smooth muscle and Type II alveolar epithelial cells. In cultured endothelial cells, a single exposure to the pyrrolic derivative of monocrotaline (MCTP) results in large cells with enlarged endoplasmic reticulum (ER) and Golgi and increased vacuoles. However, these cells fail to enter mitosis. Largely based upon data from endothelial cells, we proposed earlier that a disruption of the trafficking and mitosis-sensor functions of the Golgi (the 'Golgi blockade' hypothesis) may represent the subcellular mechanism leading to MCTP-induced megalocytosis. In the present study, we investigated the applicability of the Golgi blockade hypothesis to epithelial cells. MCTP induced marked megalocytosis in cultures of lung A549 and breast MCF-7 cells. This was associated with a change in the distribution of the cis-Golgi scaffolding protein GM130 from a discrete juxtanuclear localization to a circumnuclear distribution consistent with an anterograde block of GM130 trafficking to/through the Golgi. There was also a loss of plasma membrane caveolin-1 and E-cadherin, cortical actin together with a circumnuclear accumulation of clathrin heavy chain (CHC) and {alpha}-tubulin. Flotation analyses revealed losses/alterations in the association of caveolin-1, E-cadherin and CHC with raft microdomains. Moreover, megalocytosis was accompanied by an enhanced unfolded protein response (UPR) as evidenced by nuclear translocation of Ire1{alpha} and glucose regulated protein 58 (GRP58/ER-60/ERp57) and a circumnuclear accumulation of PERK kinase and protein disulfide isomerase (PDI). These data further support the hypothesis that an MCTP-induced Golgi blockade and enhanced UPR may represent the subcellular mechanism leading to enlargement of ER and Golgi and subsequent megalocytosis.

  19. Morphological and physicochemical properties of dip-coated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]} (PPNB) thin films: towards photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Mouchaal, Younes; Gherrass, Hamou; Bendoukha Reguig, Abdelkarim; Hachemaoui, Aïcha; Yahiaoui, Ahmed; Makha, Mohamed; Khelil, Abdelbacet; Bernede, Jean-Christian

    2015-02-01

    A new material: conjugated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]}, that we called (PPNB), has been synthesized and characterized. The cyclic voltammetry has been used in order to estimate first oxidation (Ep) and reduction (En) potentials of our polymer. These values have been assigned, respectively, to the position of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and determination of the energy band gap which have been estimated to be 6.16, 3.89 and 2.27 eV respectively. Energy levels values of the HOMO and LUMO of the PPNB polymeric donor material were evaluated and the results are compatible with an electron transfer to C60 within an eventual junction, such values show that PPNB could be probed for applications in organic solar cells as donor material. PPNB Thin films have been deposited by dip-coating technique from Dichloromethane solvent with different polymer concentrations, and a dipping speed of 3.0 cm/min. For morphological characterization of the films scanning electron microscopy (SEM) was carried out. The samples, when observed by SEM, reveals that the films deposited are less dense, uniform. Cross-sectional SEM micrographs PPNB films show that thickness of the layers is homogeneous and has value of 35-40 nm. Optical characteristics of the polymer thin films were studied using UV-vis spectroscopy; absorption of wide range of wavelengths from 350 to 700 nm was observed. The optical band gap energy ranges between 1.9 eV and 1.94 eV. Based on these analyzes we realized heterojunction organic solar cells with the structure: ITO/Au/PPNB/C60/BCP/Al, the cells had a photovoltaique effect after J-V measuring, however the efficiency of photo generation under AM1.5 illumination was weak (about 0.02%) and needs to be improved.

  20. Marked Consequences of Systematic Oligothiophene Catenation in Thieno[3,4-c]pyrrole-4,6-dione and Bithiopheneimide Photovoltaic Copolymers

    SciTech Connect

    Zhou, Nanjia; Guo, Xugang; Ponce Ortiz, Rocio; Harschneck, Tobias; Manley, Eric F.; Lou, Sylvia J.; Hartnett, Patrick E.; Yu, Xinge; Horwitz, Noah E.; Mayorga Burrezo, Paula; Aldrich, Thomas J.; Lopez Navarrete, Juan T.; Wasielewski, Michael R.; Chen, Lin X.; Chang, Robert P. H.; Facchetti, Antonio; Marks, Tobin J.

    2015-10-07

    As effective building blocks for high-mobility transistor polymers, oligothiophenes are receiving attention for polymer solar cells (PSCs) because the resulting polymers can effectively suppress charge recombination. Here we investigate two series of in-chain donor-acceptor copolymers, PTPDnT and PBTInT, based on thieno[3,4-c]pyrrole-4,6-dione (TPD) or bithiopheneimide (BTI) as electron acceptor units, respectively, and oligothiophenes (nTs) as donor counits, for high-performance PSCs. Intramolecular S···O interaction leads to more planar TPD polymer backbones, however backbone torsion yields greater open-circuit voltages for BTI polymers. Thiophene addition progressively raises polymer HOMOs but marginally affects their band gaps. FT-Raman spectra indicate that PTPDnT and PBTInT conjugation lengths scale with nT catenation up to n = 3 and then saturate for longer oligomer. Furthermore, the effects of oligothiophene alkylation position are explored, revealing that the alkylation pattern greatly affects film morphology and PSC performance. The 3T with “outward” alkylation in PTPD3T and PBTI3T affords optimal π-conjugation, close stacking, long-range order, and high hole mobilities (0.1 cm2/(V s)). These characteristics contribute to the exceptional ~80% fill factors for PTPD3T-based PSCs with PCE = 7.7%. The results demonstrate that 3T is the optimal donor unit among nTs (n = 1-4) for photovoltaic polymers. Grazing incidence wide-angle X-ray scattering, transmission electron microscopy, and time-resolved microwave conductivity measurements reveal that the terthiophene-based PTPD3T blend maintains high crystallinity with appreciable local mobility and long charge carrier lifetime. These results provide fundamental materials structure-device performance correlations and suggest guidelines for designing oligothiophene-based polymers with optimal thiophene catenation and appropriate alkylation pattern to maximize PSC performance.

  1. Precise sequence control in linear and cyclic copolymers of 2,5-bis(2-thienyl)pyrrole and aniline by DNA-programmed assembly.

    PubMed

    Chen, Wen; Schuster, Gary B

    2013-03-20

    A series of linear and cyclic, sequence controlled, DNA-conjoined copolymers of aniline (ANi) and 2,5-bis(2-thienyl)pyrrole (SNS) were synthesized. In one approach, linear copolymers were prepared from complementary DNA oligomers containing covalently attached SNS and ANi monomers. Hybridization of the oligomers aligns the monomers in the major groove of the DNA. Treatment of the SNS- and ANi-containing duplexes with horseradish peroxidase (HRP) and H2O2 causes rapid and efficient polymerization. In this way, linear copolymers (SNS)4(ANi)6 and (ANi)2(SNS)2(ANi)2(SNS)2(ANi)2 were prepared and analyzed. A second approach to the preparation of linear and cyclic copolymers of ANi and SNS employed a DNA encoded module strategy. In this approach, single-stranded DNA oligomers composed of a central region containing (SNS)6 or (ANi)5 covalently attached monomer blocks and flanking 5'- and 3'-single-strand DNA recognition sequences were combined in buffer solution. Self-assembly of these oligomers by Watson-Crick base pairing of the recognition sequences creates linear or cyclic arrays of SNS and ANi monomer blocks. Treatment of these arrays with HRP/H2O2 causes rapid and efficient polymerization to form copolymers having patterns such as cyclic BBA and linear ABA, where B stands for an (SNS)6 block and A stands for an (ANi)5 block. These DNA-conjoined copolymers were characterized by melting temperature analysis, circular dichroism spectroscopy, native and denaturing polyacrylamide gel electrophoresis, and UV-visible-near-IR optical spectroscopy. The optical spectra of these copolymers are typical of those of conducting polymers and are uniquely dependent on the specific order of monomers in the copolymer. PMID:23448549

  2. Controlling pyridinic, pyrrolic, graphitic, and molecular nitrogen in multi-wall carbon nanotubes using precursors with different N/C ratios in aerosol assisted chemical vapor deposition.

    PubMed

    Bulusheva, L G; Okotrub, A V; Fedoseeva, Yu V; Kurenya, A G; Asanov, I P; Vilkov, O Y; Koós, A A; Grobert, N

    2015-10-01

    Nitrogen-containing multi-wall carbon nanotubes (N-MWCNTs) were synthesized using aerosol assisted chemical vapor deposition (CVD) techniques in conjunction with benzylamine:ferrocene or acetonitrile:ferrocene mixtures. Different amounts of toluene were added to these mixtures in order to change the N/C ratio of the feedstock. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy detected pyridinic, pyrrolic, graphitic, and molecular nitrogen forms in the N-MWCNT samples. Analysis of the spectral data indicated that whilst the nature of the nitrogen-containing precursor has little effect on the concentrations of the different forms of nitrogen in N-MWCNTs, the N/C ratio in the feedstock appeared to be the determining factor. When the N/C ratio was lower than ca. 0.01, all four forms existed in equal concentrations, for N/C ratios above 0.01, graphitic and molecular nitrogen were dominant. Furthermore, higher concentrations of pyridinic nitrogen in the outer shells and N2 molecules in the core of the as-produced N-MWCNTs suggest that the precursors were decomposed into individual atoms, which interacted with the catalyst surface to form CN and NH species or in fact diffused through the bulk of the catalyst particles. These findings are important for a better understanding of possible growth mechanisms for heteroatom-containing carbon nanotubes (CNTs) and therefore paving the way for controlling the spatial distribution of foreign elements in the CNTs using CVD processes. PMID:26104737

  3. Preclinical Study of Novel Gene Silencer Pyrrole-Imidazole Polyamide Targeting Human TGF-β1 Promoter for Hypertrophic Scars in a Common Marmoset Primate Model

    PubMed Central

    Igarashi, Jun; Fukuda, Noboru; Inoue, Takashi; Nakai, Shigeki; Saito, Kosuke; Fujiwara, Kyoko; Matsuda, Hiroyuki; Ueno, Takahiro; Matsumoto, Yoshiaki; Watanabe, Takayoshi; Nagase, Hiroki; Bando, Toshikazu; Sugiyama, Hiroshi; Itoh, Toshio; Soma, Masayoshi

    2015-01-01

    We report a preclinical study of a pyrrole-imidazole (PI) polyamide that targets the human transforming growth factor (hTGF)-β1 gene as a novel transcriptional gene silencer in a common marmoset primate model. We designed and then synthesized PI polyamides to target the hTGF-β1 promoter. We examined effects of seven PI polyamides (GB1101-1107) on the expression of hTGF-β1 mRNA stimulated with phorbol 12-myristate 13-acetate (PMA) in human vascular smooth muscle cells. GB1101, GB1105 and GB1106 significantly inhibited hTGF-β1 mRNA expression. We examined GB1101 as a PI polyamide to hTGF-β1 for hypertrophic scars in marmosets in vivo. Injection of GB1101 completely inhibited hypertrophic scar formation at 35 days post-incision and inhibited cellular infiltration, TGF-β1 and vimentin staining, and epidermal thickness. Mismatch polyamide did not affect hypertrophic scarring or histological changes. Epidermis was significantly thinner with GB1101 than with water and mismatch PI polyamides. We developed the PI polyamides for practical ointment medicines for the treatment of hypertrophic scars. FITC-labeled GB1101 with solbase most efficiently distributed in the nuclei of epidermal keratinocytes, completely suppressed hypertropic scarring at 42 days after incision, and considerably inhibited epidermal thickness and vimentin-positive fibroblasts. PI polyamides targeting hTGF-β1 promoter with solbase ointment will be practical medicines for treating hypertrophic scars after surgical operations and skin burns. PMID:25938472

  4. Complete dechlorination of 2,4-dichlorophenol in aqueous solution on palladium/polymeric pyrrole-cetyl trimethyl ammonium bromide/foam-nickel composite electrode.

    PubMed

    Sun, Zhirong; Wei, Xuefeng; Han, Yanbo; Tong, Shan; Hu, Xiang

    2013-01-15

    The electrochemically reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution on palladium/polymeric pyrrole-cetyl trimethyl ammonium bromide/foam-nickel electrode (Pd/PPy-CTAB/foam-Ni electrode) was investigated in this paper. Pd/PPy-CTAB/foam-Ni electrode was prepared and characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) adsorption and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The influences of some experimental factors such as the dechlorination current, dechlorination time and the initial pH on the removal efficiency and the current efficiency of 2,4-DCP dechlorination on Pd/PPy-CTAB/foam-Ni electrode were studied. Complete removal of 2,4-DCP was achieved and the current efficiency of 47.4% could be obtained under the conditions of the initial pH of 2.2, the dechlorination current of 5 mA and the dechlorination time of 50 min when the initial 2,4-DCP concentration was 100 mg L(-1). The analysis of high performance liquid chromatography (HPLC) identified that the intermediate products were 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP). The final products were mainly phenol. Its further reduction product cyclohexanone was also detected. The electrocatalytic dechlorination pathways of 2,4-DCP on Pd/PPy-CTAB/foam-Ni electrode were discussed. The stability of the electrode was favorable that it could keep dechlorination efficiency at 100% after having been reused 10 times. Results revealed that the stable prepared Pd/PPy-CTAB/foam-Ni electrode presented a good application prospect in dechlorination process with high effectiveness and low cost. PMID:23270952

  5. Study of conformations and hydrogen bonds in the configurational isomers of pyrrole-2-carbaldehyde oxime by 1H, 13C and 15N NMR spectroscopy combined with MP2 and DFT calculations and NBO analysis.

    PubMed

    Afonin, Andrei V; Ushakov, Igor A; Pavlov, Dmitry V; Ivanov, Andrei V; Mikhaleva, Al'bina I

    2010-09-01

    The (1)H, (13)C and (15)N NMR studies have shown that the E and Z isomers of pyrrole-2-carbaldehyde oxime adopt preferable conformation with the syn orientation of the oxime group with respect to the pyrrole ring. The syn conformation of E and Z isomers of pyrrole-2-carbaldehyde oxime is stabilized by the N-H...N and N-H...O intramolecular hydrogen bonds, respectively. The N-H...N hydrogen bond in the E isomer causes the high-frequency shift of the bridge proton signal by about 1 ppm and increase the (1)J(N, H) coupling by approximately 3 Hz. The bridge proton shows further deshielding and higher increase of the (1)J(N, H) coupling constant due to the strengthening of the N-H...O hydrogen bond in the Z isomer. The MP2 calculations indicate that the syn conformation of E and Z isomers is by approximately 3.5 kcal/mol energetically less favorable than the anti conformation. The calculations of (1)H shielding and (1)J(N, H) coupling in the syn and anti conformations allow the contribution to these constants from the N-H...N and N-H...O hydrogen bondings to be estimated. The NBO analysis suggests that the N-H...N hydrogen bond in the E isomer is a pure electrostatic interaction while the charge transfer from the oxygen lone pair to the antibonding orbital of the N-H bond through the N-H...O hydrogen bond occurs in the Z isomer. PMID:20623827

  6. Organocatalytic Asymmetric Michael/Friedel-Crafts Cascade Reaction of 3-Pyrrolyl-oxindoles and α,β-Unsaturated Aldehydes for the Construction of Chiral Spiro[5,6-dihydropyrido[1,2-a]pyrrole-3,3'-oxindoles].

    PubMed

    You, Yong; Cui, Bao-Dong; Zhou, Ming-Qiang; Zuo, Jian; Zhao, Jian-Qiang; Xu, Xiao-Ying; Zhang, Xiao-Mei; Yuan, Wei-Cheng

    2015-06-01

    An efficient and unprecedented organocatalytic asymmetric reaction of 3-pyrrolyl-oxindoles with α,β-unsaturated aldehydes to generate spirocyclic oxindole compounds was developed. The reactions were catalyzed by diphenylprolinol silyl ether and 2-fluorobenzoic acid via an asymmetric Michael/Friedel-Crafts cascade process, followed by dehydration with p-toluenesulfonic acid to afford a wide variety of structurally diverse spiro[5,6-dihydropyrido[1,2-a]pyrrole-3,3'-oxindole] derivatives in high yields (up to 93%) and with high to excellent diastereo- and enantioselectivities (up to >99:1 dr and 97% ee). PMID:25984596

  7. An approach towards azafuranomycin analogs by gold-catalyzed cycloisomerization of allenes: synthesis of (αS,2R)-(2,5-dihydro-1H-pyrrol-2-yl)glycine

    PubMed Central

    Erdsack, Jörg

    2013-01-01

    Summary The synthesis of (αS,2R)-(2,5-dihydro-1H-pyrrol-2-yl)glycine (22, normethylazafuranomycin) by the gold-catalyzed cycloisomerization of α-aminoallene 17 is described. The target molecule was synthesized in 13 linear steps from Cbz-protected Garner aldehyde (R)-2 in an overall yield of 2.4%. The approach was first examined in model studies, which afforded the alkylated azafuranomycin derivative 13a in 2.9% yield over 12 steps. PMID:24204404

  8. A Dual-Responsive Bola-Type Supra-amphiphile Constructed from a Water-Soluble Calix[4]pyrrole and a Tetraphenylethene-Containing Pyridine Bis-N-oxide.

    PubMed

    Chi, Xiaodong; Zhang, Huacheng; Vargas-Zúñiga, Gabriela I; Peters, Gretchen M; Sessler, Jonathan L

    2016-05-11

    Complexation between a water-soluble calix[4]pyrrole and a ditopic pyridine N-oxide derivative in aqueous media produces a bola-type supra-amphiphile that self-assembles to produce higher order morphologies, including multilamellar vesicles and micelles depending on the pH. The present bola-type supra-amphiphile exhibits strong fluorescence due to structural changes and aggregation induced by host-guest complexation. The resulting structures may be used to recognize, encapsulate, and release non-fluorescent, water-soluble small molecules. PMID:27123813

  9. Cu/Mn co-oxidized cyclization for the synthesis of highly substituted pyrrole derivatives from amino acid esters: a strategy for the biomimetic syntheses of lycogarubin C and chromopyrrolic acid.

    PubMed

    Zhou, Nini; Xie, Tao; Liu, Lin; Xie, Zhixiang

    2014-07-01

    An effective and concise approach to synthesis of tetrasubstituted pyrroles from readily available amino acid esters by the promotion of Cu(OAc)2 in conjunction with Mn(OAc)3 has been developed. This reaction proceeds through multiple dehydrogenations, deamination, and oxidative cyclization. This oxidized system tolerates substrates bearing various electron-donating or electron-withdrawing groups. With this methodology, several key intermediates of natural products have been effectively prepared, and the total syntheses of lycogarubin C and chromopyrrolic acid have been completed in high efficiency. PMID:24921938

  10. Crystal structure of diethyl 3,3′-{2,2′-(1E)-[1,4-phenyl­enebis(azan-1-yl-1-yl­idene)]bis­(methan-1-yl-1-yl­idene)bis­(1H-pyrrole-2,1-di­yl)}di­propano­ate

    PubMed Central

    Alshawi, Jasim; Yousif, Muoayed; Timco, Gregore; Vitorica Yrezabal, Inigo J.; Winpenny, Richard; Al-Jeboori, Mohamad J.

    2015-01-01

    The complete mol­ecule of the title compound, C26H30N4O4, is generated by crystallographic inversion symmetry. The dihedral angle between the planes of the benzene and pyrrole rings is 45.20 (11)°; the N atom bonded to the the benzene ring and the pyrrole N atom are in a syn conformation. The side chain adopts an extended conformation [N—C—C—C = 169.07 (17)° and C—O—C—C = −176.54 (17)°]. No directional inter­actions could be identified in the crystal packing. PMID:26029445

  11. Crystal structure of diethyl 3,3'-{2,2'-(1E)-[1,4-phenyl-enebis(azan-1-yl-1-yl-idene)]bis-(methan-1-yl-1-yl-idene)bis-(1H-pyrrole-2,1-di-yl)}di-propano-ate.

    PubMed

    Alshawi, Jasim; Yousif, Muoayed; Timco, Gregore; Vitorica Yrezabal, Inigo J; Winpenny, Richard; Al-Jeboori, Mohamad J

    2015-04-01

    The complete mol-ecule of the title compound, C26H30N4O4, is generated by crystallographic inversion symmetry. The dihedral angle between the planes of the benzene and pyrrole rings is 45.20 (11)°; the N atom bonded to the the benzene ring and the pyrrole N atom are in a syn conformation. The side chain adopts an extended conformation [N-C-C-C = 169.07 (17)° and C-O-C-C = -176.54 (17)°]. No directional inter-actions could be identified in the crystal packing. PMID:26029445

  12. Structure Sensitivity of Carbon-Nitrogen Ring Opening: Impact of Platinum Particle Size from below 1 to 5 nm upon Pyrrole Hydrogenation Product Selectivity over Monodisperse Platinum Nanoparticles Loaded onto Mesoporous Silica

    SciTech Connect

    Kuhn, John N.; Huang, Wenyu; Tsung, Chia-Kuang; Zhang, Yawen; Somorjai, Gabor A.

    2008-07-01

    The ability to control fundamental properties (e.g., particle size, surface structure, and metal-oxide interface) in order to design highly selective heterogeneous catalysts would greatly reduce energy intensive separations. Particle size dependence (i.e., structure sensitivity) upon selectivity can now be examined with well defined nanoparticles (NPs) because of advances in synthetic chemistry. Colloidal chemistry has provided means for synthesizing monodisperse Pt NPs as small as {approx}2 nm. Using a dendrimer templated approach, Pt NPs smaller than 1 nm--a new size regime for studying size induced effects in heterogeneous catalysis--can be synthesized (Scheme 1). In this contribution, we report that ring opening for pyrrole hydrogenation is distinctly different for Pt NPs smaller than 2 nm. This insight has not been demonstrated for hydrogenation of cyclic heteroatom bonds to the best of our knowledge. This finding adds fundamental insight into hydrodenitrogenation (HDN) chemistry, which is important for fuel processing and involves removal of N-containing organics. Advances in HDN catalysis are needed to meet new fuel quality regulations because N-containing organics inhibit hydrodesulfurization (HDS) through competitive adsorption and poison acid catalysts, which are used for downstream processing and as supports for HDS catalysts. Pyrrole was selected as the reactant because organics with 5-member N-containing rings are the most common components in fuel.

  13. Effects of 5-Amyno-4-(1,3-benzothyazol-2-yn)-1-(3-methoxyphenyl)-1,2-dihydro-3H-pyrrol-3-one Intake on Digestive System in a Rat Model of Colon Cancer

    PubMed Central

    Kuznietsova, Halyna M.; Luzhenetska, Valentyna K.; Kotlyar, Iryna P.; Rybalchenko, Volodymyr K.

    2015-01-01

    Introduction. Pyrrol derivate 5-amyno-4-(1,3-benzothyazol-2-yn)-1-(3-methoxyphenyl)-1,2-dihydro-3H-pyrrol-3-one (D1) has shown antiproliferative activities in vitro, so investigation of the impact of D1 intake on gut organs in rats that experienced colon cancer seems to be necessary. Materials and Methods. D1 at the dose of 2.3 mg/kg was administered per os daily for 27 (from the 1st day of experiment) or 7 (from the 21st week of experiment) weeks to rats that experienced 1,2-dimethylhydrazine (DMH)-induced colon cancer for 20 weeks. 5-Fluorouracil (5FU) was chosen as reference drug and was administered intraperitoneally weekly for 7 weeks (from the 21st week of experiment) at the dose of 45 mg/kg. Results. Antitumor activity of D1 comparable with the 5FU one against DMH-induced colon cancer in rats was observed (decrease of tumor number and tumor total area up to 46%). D1 attenuated the inflammation of colon, gastric and jejunal mucosa, and the liver, caused by DMH, unlike 5FU, aggravating the latter. In addition, D1 partially normalized mucosa morphometric parameters suggesting its functional restore. Conclusions. D1 possesses, comparable with 5-fluorouracil antitumor efficacy, less damaging effects on the tissues beyond cancerous areas and contributes to partial morphological and functional gut organs recovery. PMID:26504896

  14. Synthesis of 7-15N-Oroidin and Evaluation of Utility for Biosynthetic Studies of Pyrrole-Imidazole Alkaloids by Microscale1H-15N HSQC and FTMS†

    PubMed Central

    Wang, Yong-Gang; Morinaka, Brandon I.; Reyes, Jeremy Chris P.; Wolff, Jeremy H.; Romo, Daniel; Molinski, Tadeusz F.

    2010-01-01

    Numerous marine-derived pyrrole-imidazole alkaloids (PIAs), ostensibly derived from the simple precursor oroidin, 1a, have been reported and have garnered intense synthetic interest due to their complex structures and in some cases biological activity; however very little is known regarding their biosynthesis. We describe a concise synthesis of 7-15N-oroidin (1d) from urocanic acid and a direct method for measurement of 15N incorporation by pulse labeling and analysis by 1D 1H-15N HSQC NMR and FTMS. Using a mock pulse labeling experiment, we estimate the limit of detection (LOD) for incorporation of newly biosynthesized PIA by 1D 1H-15N HSQC to be 0.96 μg equivalent of 15N oroidin (2.4 nmole) in a background of 1500 μg unlabeled oroidin (about 1 part per 1600). 7-15N-Oroidin will find utility in biosynthetic feeding experiments with live sponges to provide direct information to clarify the pathways leading to more complex pyrrole-imidazole alkaloids. PMID:20095632

  15. One-pot, four-component synthesis of novel cytotoxic agents 1-(5-aryl-1,3,4-oxadiazol-2-yl)-1-(1H-pyrrol-2-yl)methanamines.

    PubMed

    Ramazani, Ali; Khoobi, Mehdi; Torkaman, Azar; Nasrabadi, Fatemeh Zeinali; Forootanfar, Hamid; Shakibaie, Mojtaba; Jafari, Mandana; Ameri, Alieh; Emami, Saeed; Faramarzi, Mohammad Ali; Foroumadi, Alireza; Shafiee, Abbas

    2014-05-01

    A series of N-benzyl-1-(5-aryl-1,3,4-oxadiazol-2-yl)-1-(1H-pyrrol-2-yl)methanamines were synthesized via one-pot reaction of appropriate benzylamine, pyrrole-2-carbaldehyde, (N-isocyanimino)triphenylphosphorane, and a carboxylic acid. The anti-tumor potential of title compounds was tested against several cancer cell lines by using MTT assay. Some tested compounds including 5e, 5p and 5q exhibited comparable or better cytotoxic activity against A549, HT29 or HT1080 cells in comparison to the reference drug doxorubicin. Also, the cytotoxic activity of compounds 5d and 5n against MCF-7 was better than that of doxorubicin. Compound 5n with IC50 value of 4.3 μM was 4-fold more potent than doxorubicin. The structure-activity relationship study revealed that the introduction of halogen atoms on both 5-phenyl ring and N-benzyl part improved the cytotoxic activity against all tested cell lines. PMID:24681979

  16. Polypyrrole growth on YBa{sup 2}Cu{sup 3}O{sup 7-{delta}} modified with a self-assembled monolayer of N-(3-aminopropyl)pyrrole: Hardwiring the `electroactive hot spots` on a superconductor electrode

    SciTech Connect

    Lo, R.K.; Ritchie, J.E.; Zhou, J.P.; Zhao, J.; McDevitt, J.T.; Xu, F.; Mirkin, C.A.

    1996-11-13

    This paper describes a new method for controlling the deposition of conductive polymer systems onto high-T{sup c} superconductor surfaces. This method relies on the spontaneous adsorption of the pyrrole-terminated alkylamine reagent 1 onto YBa{sup 2}Cu{sup 3}O{sup 7-{delta}} prior to polymerization. Large changes in the polymer growth rates and vast improvements in the polymer morphology are obtained with the use of such adsorbed monolayers. As described, the adsorbed monolayer structures promote radically different polymer deposition properties from those observed previously for the more traditional electrode materials (i.e., Au, Pt, etc.). These unusual observations provided valuable insight into the electrochemical characteristics and local surface electroactivity/conductivity properties of oriented cuprate superconductor films. 16 refs., 2 figs.

  17. Ethyl 4-(4-chloro­anilino)-1-(4-chloro­phen­yl)-2-methyl-5-oxo-2,5-di­hydro-1H-pyrrole-2-carboxyl­ate

    PubMed Central

    Akkurt, Mehmet; Mohamed, Shaaban K.; Elremaily, Mahmoud A.A.; Santoyo-Gonzalez, Francisco; Albayati, Mustafa R.

    2013-01-01

    In the title compound, C20H18Cl2N2O3, the dihedral angles between the central 2,5-di­hydro-1H-pyrrole ring and the phenyl rings are 74.87 (9) and 29.09 (9)°. Intra­molecular N—H⋯O and C—H⋯O hydrogen bonds occur. In the crystal, pairs of N—H⋯O hydrogen bonds link adjacent mol­ecules into inversion dimers and form an R 1 2(6)R 2 2(10)R 1 2(6) ring motif through C—H⋯O hydrogen bonds. PMID:24454212

  18. AzaHx, a novel fluorescent, DNA minor groove and G·C recognition element: Synthesis and DNA binding properties of a p-anisyl-4-aza-benzimidazole-pyrrole-imidazole (azaHx-PI) polyamide.

    PubMed

    Satam, Vijay; Babu, Balaji; Patil, Pravin; Brien, Kimberly A; Olson, Kevin; Savagian, Mia; Lee, Megan; Mepham, Andrew; Jobe, Laura Beth; Bingham, John P; Pett, Luke; Wang, Shuo; Ferrara, Maddi; Bruce, Chrystal D; Wilson, W David; Lee, Moses; Hartley, John A; Kiakos, Konstantinos

    2015-09-01

    The design, synthesis, and DNA binding properties of azaHx-PI or p-anisyl-4-aza-benzimidazole-pyrrole-imidazole (5) are described. AzaHx, 2-(p-anisyl)-4-aza-benzimidazole-5-carboxamide, is a novel, fluorescent DNA recognition element, derived from Hoechst 33258 to recognize G·C base pairs. Supported by theoretical data, the results from DNase I footprinting, CD, ΔT(M), and SPR studies provided evidence that an azaHx/IP pairing, formed from antiparallel stacking of two azaHx-PI molecules in a side-by-side manner in the minor groove, selectively recognized a C-G doublet. AzaHx-PI was found to target 5'-ACGCGT-3', the Mlu1 Cell Cycle Box (MCB) promoter sequence with specificity and significant affinity (K(eq) 4.0±0.2×10(7) M(-1)). PMID:26122210

  19. Thieno[3,4-c]Pyrrole-4,6-Dione and Dithiophene-Based Conjugated Polymer for Organic Field Effect Transistors: High Mobility Induced by Synergic Effect of H-Bond and Vinyl Linkage.

    PubMed

    Qing, Wanmei; Gong, Xiaodi; Liang, Xianfeng; Wang, Yuancheng; Yang, Sifen; Tan, Luxi; Ma, Yanping; Liu, Zitong; Li, Jing

    2016-08-01

    Here, a conjugated polymer VTTPD based on thieno[3,4-c]pyrrole-4,6-dione (TPD) and dithiophene with vinyl as linker is synthesized and characterized. Electrochemical and optical studies indicate the LUMO and HOMO energies of the polymer are -3.70 and -5.39 eV. Theoretical calculation with density functional theory suggests that H-bonds are formed between the TPD carbonyl (O) and its neighboring vinyl (H) which benefit the planarity and π-conjugation of the polymer backbone. Bottom contact bottom gate organic field effect transistor devices based on VTTPD are fabricated and examined in air. After annealing at 160 °C, the devices exhibit excellent performance of μh = 0.4 cm(2) V(-1) s(-1) , Ion/off = 10(6) , Vth within -10 V to -5 V. Thin film morphologies before and after the annealing process are also investigated with XRD and AFM. PMID:27304842

  20. Spectral analysis, structural elucidation, and evaluation of both nonlinear optical properties and chemical reactivity of a newly synthesized ethyl-3,5-dimethyl-4-[(toluenesulfonyl)-hydrazonomethyl]-1H-pyrrole-2-carboxylate through experimental studies and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonam

    2013-12-01

    As part of study of hydrazide-hydrazones, we have synthesized ethyl-3,5-dimethyl-4-[(toluenesulfonyl)-hydrazonomethyl]-1H-pyrrole-2-carboxylate (EDTHMPC) and characterized by elemental analysis, FT-IR, UV-Vis, 1H, 13C NMR and Mass spectroscopy. The structure, spectral and thermodynamic parameters of EDTHMPC were quantum chemically calculated performing density functional level theory (DFT) with B3LYP functional and 6-31G (d,p) basis set. Electrophilic charge transfer (ECT) values of interacting molecules indicate that charge flows from p-toluene sulphonyl-hydrazide to ethyl-3,5-dimethyl-4-formyl-1H-pyrrole-2-carboxylate confirming the formation of product by nucleophilic attack. The calculated and experimental wavenumbers analysis confirms the formation of dimer. The calculated changes in thermodynamic quantities during dimer formation in gaseous phase have the negative values for ΔH, ΔG (kcal/mol) and ΔS (cal/mol-K) indicating that the dimer formation is exothermic and will proceed only at low temperature. The strength and nature of hydrogen bonding and weak interactions in dimer have been analyzed by 'Quantum theory of atoms in molecules' (QTAIM) and found to be five types of interactions in which three types are (C⋯N, CH⋯O and CH⋯HC) intramolecular and two types are (CO⋯HN and CH⋯OC) intermolecular. The calculated binding energy of dimer using DFT and QTAIM theory are 14.32 and 15.41 kcal/mol, respectively. The β0 value for monomer is calculated as 11.54 x 10-30 esu indicating microscopic nonlinear optical (NLO) behavior with non-zero values.

  1. Synthesis, crystal structure, characterization and biological activity of 2,5-hexanedione bis(isonicotinylhydrazone) and N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide complexes.

    PubMed

    Jeragh, Bakir; Ali, Mayada S; El-Asmy, Ahmed A

    2015-11-01

    The reaction between 2,5-hexanedione and isonicotinic acid hydrazide in EtOH gave two products. The ethanol insoluble product was identified as 2,5-hexanedione bis(isonicotinylhydrazone) [HINH] and the soluble ethanol product as N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide [DINA]. A series of Cr(3+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Pd(2+) complexes of HINH and Co(2+), Cu(2+), Zn(2+) and Hg(2+) complexes of DINA have been synthesized and structurally characterized. Based on the elemental analysis, mass spectra and molar conductance, the complexes have assigned the proposed imperical formulae. The crystal structures of N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide and its Zn(2+) and Hg(2+) complexes have been solved by X-ray diffraction having [Zn(DINA)2Cl2] and [Hg(DINA)2Cl2] in a tetrahedral structure. In the DINH complexes, the ligand coordinates as a monodentate through the pyridine nitrogen. On the other hand, HINH behaves as a tetradentate (neutral or binegative) manner with the two metal ions. The magnetic moments and electronic spectra of all complexes provide tetrahedral, square-planar, trigonal biyramid and/or octahedral structure. The thermal decomposition of the complexes revealed the outer and inner solvents as well as the end product. The steady part of [Zn(DINA)2Cl2] and [Hg(DINA)2Cl2] thermograms till 303 and 286 °C indicates the absence of any outside solvents. All compounds have activity against bacteria more than fungi. [Cd4(HINH)Cl8]·3H2O has the highest values. PMID:26073596

  2. A Quasi-relativistic Density Functional Theory Study of the Actinyl(VI, V) (An = U, Np, Pu) Complexes with a Six-Membered Macrocycle Containing Pyrrole, Pyridine, and Furan Subunits.

    PubMed

    Lan, Jian-Hui; Wang, Cong-Zhi; Wu, Qun-Yan; Wang, Shu-Ao; Feng, Yi-Xiao; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-08-27

    Actinyl(VI, V) (An = U, Np and Pu) complexes of the recently reported hybrid macrocycle, cyclo[1]furan[1]pyridine[4]pyrrole (denoted as H4L), have been studied using density functional theory in combination with the small-core scalar-relativistic effective core potentials and corresponding (14s13p10d8f6g)/[ 10s9p5d4f3g] basis sets in the segmented contraction scheme. On the basis of our calculations, the pyrrole nitrogen atoms that possess the shortest An-L bonds and strongest basicity are the main donor atoms that contribute to the formation of actinyl(VI, V) complexes. The natural population analysis (NPA) suggests higher ligand-to-actinyl charge transfer in the actinyl(VI) complexes than in their actinyl(V) analogues, which account for the higher decomposition energies of the former. A significant actinide-to-ligand spin density delocalization in the uranyl(V) and neptunyl(V) complexes was observed owing to the redistribution of spin density caused by complexation. A thermodynamic analysis indicates that the formation of the actinyl(VI, V) complexes are exothermic reactions in CH2Cl2 solvent, where the uranyl cations show the highest selectivity. In aqueous solution containing chloride ions, for complexing with macrocycle H4L, the plutonyl(VI) and uranyl(V) cations possess the highest selectivity among actinyl(VI) and (V) cations, respectively. This work can shed light on the design of macrocycle complexes for actinide recognition and extraction in the future. PMID:26226188

  3. Studies on molecular weaker interactions, spectroscopic analysis and chemical reactivity of synthesized ethyl 3,5-dimethyl-4-[3-(2-nitro-phenyl)-acryloyl]-1H-pyrrole-2-carboxylate through experimental and quantum chemical approaches

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Baboo, Vikas; Rawat, Poonam; Gupta, V. P.

    2013-04-01

    Ethyl 3,5-dimethyl-4-[3-(2-nitro-phenyl)-acryloyl]-1H-pyrrole-2-carboxylate (EDNPAPC) has been synthesized and characterized by 1H NMR, UV-Vis, FT-IR and Mass spectroscopy. Geometrical, spectral, thermodynamic properties have been calculated and evaluated using DFT level of theory, B3LYP functional and 6-31G(d,p) basis set. The observed absorption peaks at 364, 308 and 256 nm are corresponds to the calculated electronic transitions at 352, 286 nm and 252 nm respectively. The experimental data shows red shift in comparison to the calculated. The detailed vibrational analysis has been carried out with the aid of potential energy distribution (PED) and the experimental FTIR peaks confirm red shifts in Nsbnd H and Cdbnd O stretching bond as result of dimer formation. The multiple interactions present in the molecule have been evaluated with the help of QTAIM theory. The ellipticity values confirm the presence of resonance assisted hydrogen bonding in dimer formation. The binding energy of dimer formation through DFT and AIM calculations has been found to be 13.94 and 15.22 kcal/mol respectively. The binding energy of dimer after basis set superposition error (BSSE) found to be as 10.54 kcal/mol. Theoretical result from reactivity descriptors show that C6, C13 and C15 are more reactive sites for nucleophilic attack within molecule favoring the formation of heterocyclic compounds such as pyrazoline and oxazoline. The calculated β0 values for monomer and dimer are found to be as 1.8 × 10-30, 7.8 × 10-30 esu, respectively, indicating that this pyrrole chalcone is an attractive material for nonlinear optical (NLO) applications.

  4. Synthesis, vapor growth, polymerization, and characterization of thin films of novel diacetylene derivatives of pyrrole. The use of computer modeling to predict chemical and optical properties of these diacetylenes and poly(diacetylenes)

    NASA Technical Reports Server (NTRS)

    Paley, M. S.; Frazier, D. O.; Abeledeyem, H.; Mcmanus, S. P.; Zutaut, S. E.

    1992-01-01

    In the present work two diacetylene derivatives of pyrrole which are predicted by semiempirical AM1 calculations to have very different properties, are synthesized; the polymerizability of these diacetylenes in the solid state is determined, and the results are compared to the computer predictions. Diacetylene 1 is novel in that the monomer is a liquid at room temperature; this may allow for the possibility of polymerization in the liquid state as well as the solid state. Thin poly(diacetylene) films are obtained from compound 1 by growing films of the monomer using vapor deposition and polymerizing with UV light; these films are then characterized. Interestingly, while the poly(diacetylene) from 1 does not possess good nonlinear optical properties, the monomer exhibits very good third-order effects (phase conjugation) in solution. Dilute acetone solutions of the monomer 1 give intensity-dependent refractive indices on the order of 10 exp -6 esu; these are 10 exp 6 times better than for CS2.

  5. Ultrafast photoexcited dynamics probe of blends of conjugated polymerpoly{bi(dodecyl)thiophene-thieno[3,4-c]pyrrole-4,6-dione} and fullerenes for photovoltaic applications with broadband sub-10-fs visible pulse

    NASA Astrophysics Data System (ADS)

    Kao, Chih-Hsien; Yabushita, Atsushi; Su, Yu-Wei; Wei, Kung-Hwa; Lee, Yu-Hsien; Kobayashi, Takayoshi

    2016-03-01

    Conjugated polymers have been widely studied as active materials for organic solar cells, which are a promising replacement for silicon solar cells. A novel electron donor polymer of poly{bi(dodecyl)thiophene-thieno[3,4-c]pyrrole-4,6-dione} (PBTTPD) blended with an electron acceptor, [6,6]-phenyl C71 butyric acid methyl ester (PC71BM), gave a device power conversion efficiency as high as 7.3%. In the present work, we performed time-resolved absorption change spectroscopy at various mixture ratios of PC71BM in the PBTTPD/PC71BM blend. Among the obtained time constants, the shortest (60 fs) and the longest (500 fs and 15 ps) were assigned to the production and relaxation of charge-transfer (CT) states, respectively. The PC71BM blended with PBTTPD was found to suppress interchain carrier transport and increase intrachain carrier transport. The prolonged lifetime of the CT state in the equally blended PBTTPD/PC71BM film increases the probability of charge separation and thus increases the power conversion efficiency of the device.

  6. Molecular structure, spectral studies, intra and intermolecular interactions analyses in a novel ethyl 4-[3-(2-chloro-phenyl)-acryloyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate and its dimer: A combined DFT and AIM approach

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Baboo, Vikas; Rawat, Poonam; Kumar, Amit; Verma, Divya

    A newly synthesized chalcone, Ethyl 4-[3-(2-chloro-phenyl)-acryloyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate (ECPADMPC) has been characterized by 1H NMR, 13C NMR, UV-Vis, FT-IR, Mass spectroscopy and elemental analysis. Quantum chemical calculations have been performed by DFT level of theory using B3LYP functional and 6-31G(d,p) as basis set. The time dependent density functional theory (TD-DFT) is used to find the various electronic transitions within molecule. A combined theoretical and experimental wavenumber analysis confirms the existence of dimer. Topological parameters-electron density (ρBCP), Laplacian of electron density (▿2ρBCP), energetic parameters-kinetic electron energy density (GBCP), potential electron density (VBCP) and the total electron energy density (HBCP) at the bond critical points (BCP) have been analyzed by 'Atoms in molecules' AIM theory in detail. The intermolecular hydrogen bond energy of dimer is calculated as -12.3 kcal/mol using AIM calculations. AIM ellipticity analysis is carried out to confirm the presence of resonance assisted intermolecular hydrogen bonds in stabilization of dimer. The analysis clearly depicts the presence of different kind of interactions in dimer. This dimer may work as model system to understand the H-bonding interaction in biomolecules. The local reactivity descriptor analysis is performed to find the reactive sites within molecule.

  7. An investigation of the well-water quality: immunosensor for pathogenic Pseudomonas aeruginosa detection based on antibody-modified poly(pyrrole-3 carboxylic acid) screen-printed carbon electrode.

    PubMed

    Bekir, Karima; Bousimma, Feriel; Barhoumi, Houcine; Fedhila, Kais; Maaref, Abderrazak; Bakhrouf, Amina; Ben Ouada, Hafedh; Namour, Philippe; Jaffrezic-Renault, Nicole; Ben Mansour, Hedi

    2015-12-01

    In this report, we describe a new immunosensor designed for the detection and the quantification of Pseudomonas aeruginosa bacteria in water. The developed biosensing system was based on the immobilization of purified polyclonal anti P. aeruginosa antibodies on electropolymerized poly(pyrrole-3-carboxylic acid)/glassy carbon electrode. The building of the immunosensor step by step was evaluated by electrochemical measurements such as cyclic voltammetry (CV) and impedance spectroscopy (EIS). The electrochemical signature of the immunosensor was established by the change of the charge transfer resistance when the bacteria suspended in solution became attached to the immobilized antibodies. As a result, stable and high sensitive impedimetric immunosensor was obtained with a sensitivity of 0.19 kΩ/decade defined in the linear range from 10(1) to 10(7) CFU/mL of cellular concentrations. A low detection limit was obtained for the P. aeruginosa bacteria and a high selectivity when other bacteria were occasioned as well as Escherichia coli. The developed immunosensor was applied in detecting pathogenic P. aeruginosa in well-water. PMID:26178830

  8. β-Furan-Fused bis(Difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine Fluorescent Dyes in the Visible Deep-Red Region.

    PubMed

    Zhou, Lin; Xu, Defang; Gao, Huaizhi; Zhang, Chao; Ni, Fangfang; Zhao, Wenqi; Cheng, Dandan; Liu, Xingliang; Han, Aixia

    2016-09-01

    Novel β-furan-fused bis(difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (BOPHY) fluorescent dyes (F-BOPHY1-3) were prepared through an efficient process, and their structures were confirmed by (1)H NMR spectroscopy, (13)C NMR spectroscopy, MALDI-TOF HRMS, and element analysis. Their optical properties were then characterized by UV-vis absorption and photoluminescence (PL) spectroscopy. The UV-vis absorption and PL spectra of the dyes shifted to longer wavelengths relative to those of BOPHY because of the fusion of their furan rings, which extended π-conjugation of the molecules. All of the dyes exhibited large extinction coefficients (109700-12300 M(-1) cm(-1)), deep-red fluorescence emission (646-667 nm), moderate fluorescence quantum yields (0.30-0.45), as well as high chemical stability and photostability in solution. These advantageous properties show that these compounds are important to the design of efficient long-wavelength fluorescent dyes and are suitable for various applications in biotechnology and materials science. PMID:27463419

  9. Crystal structures of methyl 3-(4-iso-propyl-phen-yl)-1-methyl-1,2,3,3a,4,9b-hexa-hydro-thio-chromeno[4,3-b]pyrrole-3a-carboxyl-ate, methyl 1-methyl-3-(o-tol-yl)-1,2,3,3a,4,9b-hexa-hydro-thio-chromeno[4,3-b]pyrrole-3a-carboxyl-ate and methyl 1-methyl-3-(o-tol-yl)-3,3a,4,9b-tetra-hydro-1H-thio-chromeno[4,3-c]isoxazole-3a-carboxyl-ate.

    PubMed

    Raja, R; Suresh, M; Raghunathan, R; SubbiahPandi, A

    2015-06-01

    In the title compounds, C23H27NO2S, (I), and C21H23NO2S, (II), the pyrrole rings have envelope conformations with the C atom substituted by the benzene ring as the flap. In the third title compound, C20H21NO3S, (III), the isoxazole ring has a twisted conformation on the C-C bond substituted by the benzene ring and the carboxyl-ate group. In all three compounds, the thio-pyran ring has a half-chair conformation. The mean plane of the pyrrole ring is inclined to the mean plane of the thio-pyran ring by 57.07 (9), 58.98 (9) and 60.34 (12)° in (I), (II) and (III), respectively. The benzene rings are inclined to one another by 73.26 (10)° in (I), 65.781)° in (II) and 63.37 (13)° in (III). In the crystals of all three compounds, there are no classical hydrogen bonds present. Only in the crystal of compound (I) are mol-ecules linked by a pair of C-H⋯π inter-actions, forming inversion dimers. The isopropyl group in compound (I) is disordered over two sets of sites and has a refined occupancy ratio of 0.586 (13):0.414 (13). PMID:26090125

  10. Ethyl-2-amino-pyrrole-3-carboxylates are novel potent anticancer agents that affect tubulin polymerization, induce G2/M cell-cycle arrest, and effectively inhibit soft tissue cancer cell growth in vitro.

    PubMed

    Boichuk, Sergei; Galembikova, Aigul; Zykova, Svetlana; Ramazanov, Bulat; Khusnutdinov, Ramil; Dunaev, Pavel; Khaibullina, Svetlana; Lombardi, Vincent

    2016-08-01

    Microtubules are known to be one of the most attractive and validated targets in cancer therapy. However, the clinical use of drugs that affect the dynamic state of microtubules has been hindered by chemoresistance and toxicity issues. Accordingly, the development of novel agents that target microtubules is needed. Here, we report the identification of novel compounds with pirrole and carboxylate structures: ethyl-2-amino-pyrrole-3-carboxylates (EAPCs) that provide potent cytotoxic activities against multiple soft tissue cancer cell lines in vitro. Using the MTS cell proliferation assay, we assessed the activity of EAPCs on various cancer cell lines including leiomyosarcoma SK-LMS-1, rhabdomyosarcoma RD, gastrointestinal stromal tumor GIST-T1, A-673 Ewing's sarcoma, and U-2 OS osteosarcoma. We found that in the majority of cases, two EAPC compounds (EAPC-20 and EAPC-24) considerably inhibited cancer cell proliferation in vitro. The growth-inhibitory effects of EAPC-20 and EAPC-24 were time and dose dependent. The molecular mechanisms of action of these compounds were because of the inhibition of tubulin polymerization and induction of a robust G2/M cell-cycle arrest, leading to considerable accumulation of tumor cells in the M-phase. Finally, EAPCs induced tumor cell death by apoptotic pathways. The above-mentioned effects were also observed in most soft tissue tumor cell lines and the gastrointestinal stromal tumor cell line investigated. Taken together, our data identify potent antitumor activity of EAPCs in vitro, thus providing a novel scaffold with which to develop potent chemotherapeutic agents for cancer therapy. PMID:27129079

  11. Crystal structure of diethyl 2,2'-[((1E,1'E)-{[(1R,4R)-cyclo-hexane-1,4-di-yl]bis-(aza-nylyl-idene)}bis-(methanylyl-idene))bis-(1H-pyrrole-2,1-di-yl)]di-acetate.

    PubMed

    Alshawi, Jasim; Yousif, Muoayed; Zangana, Karzan H; Vitorica Yrezabal, Inigo J; Winpenny, Richard; Al-Jeboori, Mohamad J

    2015-03-01

    The whole mol-ecule of the title compound, C24H32N4O4, is generated by inversion symmetry. The cyclo-hexane ring adopts a chair conformation and the conformation about the C=N bonds is E. The pyrrole rings have an anti confirmation with respect to the cyclo-hexane moiety and the ethyl acetate groups have extended conformations. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds forming chains, enclosing R 2 (2)(10) ring motifs with inversion symmetry, propagating parallel to the (101) plane. PMID:25844229

  12. Crystal structure of diethyl 2,2′-[((1E,1′E)-{[(1R,4R)-cyclo­hexane-1,4-di­yl]bis­(aza­nylyl­idene)}bis­(methanylyl­idene))bis­(1H-pyrrole-2,1-di­yl)]di­acetate

    PubMed Central

    Alshawi, Jasim; Yousif, Muoayed; Zangana, Karzan H.; Vitorica Yrezabal, Inigo J.; Winpenny, Richard; Al-Jeboori, Mohamad J.

    2015-01-01

    The whole mol­ecule of the title compound, C24H32N4O4, is generated by inversion symmetry. The cyclo­hexane ring adopts a chair conformation and the conformation about the C=N bonds is E. The pyrrole rings have an anti confirmation with respect to the cyclo­hexane moiety and the ethyl acetate groups have extended conformations. In the crystal, mol­ecules are linked by pairs of C—H⋯O hydrogen bonds forming chains, enclosing R 2 2(10) ring motifs with inversion symmetry, propagating parallel to the (101) plane. PMID:25844229

  13. 4-Hydroxy-7-oxo-5-heptenoic Acid (HOHA) Lactone is a Biologically Active Precursor for the Generation of 2-(ω-Carboxyethyl)pyrrole (CEP) Derivatives of Proteins and Ethanolamine Phospholipids.

    PubMed

    Wang, Hua; Linetsky, Mikhail; Guo, Junhong; Choi, Jaewoo; Hong, Li; Chamberlain, Amanda S; Howell, Scott J; Howes, Andrew M; Salomon, Robert G

    2015-05-18

    2-(ω-Carboxyethyl)pyrrole (CEP) derivatives of proteins were previously shown to have significant pathological and physiological relevance to age-related macular degeneration, cancer and wound healing. Previously, we showed that CEPs are generated in the reaction of ε-amino groups of protein lysyl residues with 1-palmityl-2-(4-hydroxy-7-oxo-5-heptenoyl)-sn-glycero-3-phosphatidylcholine (HOHA-PC), a lipid oxidation product uniquely generated by oxidative truncation of docosahexanenate-containing phosphatidylcholine. More recently, we found that HOHA-PC rapidly releases HOHA-lactone and 2-lyso-PC (t1/2 = 30 min at 37 °C) by nonenzymatic transesterification/deacylation. Now we report that HOHA-lactone reacts with Ac-Gly-Lys-OMe or human serum albumin to form CEP derivatives in vitro. Incubation of human red blood cell ghosts with HOHA-lactone generates CEP derivatives of membrane proteins and ethanolamine phospholipids. Quantitative analysis of the products generated in the reaction HOHA-PC with Ac-Gly-Lys-OMe showed that HOHA-PC mainly forms CEP-dipeptide that is not esterified to 2-lysophosphatidycholine. Thus, the HOHA-lactone pathway predominates over the direct reaction of HOHA-PC to produce the CEP-PC-dipeptide derivative. Myleoperoxidase/H2O2/NO2(-) promoted in vitro oxidation of either 1-palmityl-2-docosahexaneoyl-sn-glycero-3-phosphatidylcholine (DHA-PC) or docosahexaenoic acid (DHA) generates HOHA-lactone in yields of 0.45% and 0.78%, respectively. Lipid oxidation in human red blood cell ghosts also releases HOHA-lactone. Oxidative injury of ARPE-19 human retinal pigmented epithelial cells by exposure to H2O2 generated CEP derivatives. Treatment of ARPE-19 cells with HOHA-lactone generated CEP-modified proteins. Low (submicromolar), but not high, concentrations of HOHA-lactone promote increased vascular endothelial growth factor (VEGF) secretion by ARPE-19 cells. Therefore, HOHA-lactone not only serves as an intermediate for the generation of CEPs but

  14. Anticancer potential of pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP) extracted from a new marine bacterium, Staphylococcus sp. strain MB30.

    PubMed

    Lalitha, P; Veena, V; Vidhyapriya, P; Lakshmi, Pragna; Krishna, R; Sakthivel, N

    2016-05-01

    Marine bacterium, strain MB30 isolated from the deep sea sediment of Bay of Bengal, India, exhibited antimicrobial activity against human pathogenic bacteria. Based on the 16S rRNA sequence homology and subsequent phylogenetic tree analysis, the strain MB30 was identified as Staphylococcus sp. The bioactive metabolite produced by the strain MB30 was purified through silica gel column chromatography and preparative HPLC. Purified metabolite was further characterized by FT-IR, LC-MS and NMR analyses. On the basis of spectroscopic data, the metabolite was identified as pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP). The PPDHMP exhibited in vitro anticancer potential against lung (A549) and cervical (HeLa) cancer cells in a dose-dependent manner with the IC50 concentration of 19.94 ± 1.23 and 16.73 ± 1.78 μg ml(-1) respectively. The acridine orange (AO)/ethidium bromide (EB) and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining of the IC50 concentration of PPDHMP-treated cancer cells exhibited an array of morphological changes such as nuclear condensation, cell shrinkage and formation of apoptotic bodies. The PPDHMP-treated cancer cells induced the progressive accumulation of fragmented DNA in a time-dependent manner. Based on the flow cytometric analysis, it has become evident that the compound was also effective in arresting the cell cycle at G1 phase. Further, the Western blotting analysis confirmed the down-regulation of cyclin-D1, cyclin dependent kinase (CDK-2), anti-apoptotic Bcl-2 family proteins (Bcl-2 and Bcl-xL), activation of caspase-9 and 3 with the cleavage of PARP. The PPDHMP-treated cancer cells also showed the inhibition of migration and invasive capacity of cancer cells. In the present investigation, for the first time, we have reported the extraction, purification and characterization of an anticancer metabolite, PPDHMP from a new marine bacterium, Staphylococcus sp. strain MB30. PMID:26852140

  15. Pyrrole-Based Conductive Polymers For Capacitors

    NASA Technical Reports Server (NTRS)

    Nagasubramanian, Ganesan; Di Stefano, Salvador

    1994-01-01

    Polypyrrole films containing various dopant anions exhibit superior capacitance characteristics. Used with nonaqueous electrolytes. Candidate for use in advanced electrochemical double-layer capacitors capable of storing electrical energy at high densities. Capacitors made of these films used in automobiles and pulsed power supplies.

  16. Crystal structure of (2-{[3,5-bis­(1,1-di­methyl­eth­yl)-4-hy­droxy­phen­yl](5-methyl-2H-pyrrol-2-yl­idene)meth­yl}-5-methyl-1H-pyrrolido-κ2 N,N′)di­fluoridoboron

    PubMed Central

    Morimoto, Yukio; Ogawa, Keizo; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi

    2015-01-01

    The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT), in which the B atom adopts a distorted BN2F2 tetra­hedral geometry: it is soluble in dimethyl sulfoxide, di­methyl­formamide and methanol. The pyrrolyl­idene­methyl­pyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031 Å) and subtends a dihedral angle of 47.09 (5)° with the plane of the pendant phenol ring. The phenol –OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C—H⋯F inter­actions generate R 2 2(22) loops. PMID:26396909

  17. Crystal structure of (2-{[3,5-bis-(1,1-di-methyl-eth-yl)-4-hy-droxy-phen-yl](5-methyl-2H-pyrrol-2-yl-idene)meth-yl}-5-methyl-1H-pyrrolido-κ(2) N,N')di-fluoridoboron.

    PubMed

    Morimoto, Yukio; Ogawa, Keizo; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi

    2015-09-01

    The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT), in which the B atom adopts a distorted BN2F2 tetra-hedral geometry: it is soluble in dimethyl sulfoxide, di-methyl-formamide and methanol. The pyrrolyl-idene-methyl-pyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031 Å) and subtends a dihedral angle of 47.09 (5)° with the plane of the pendant phenol ring. The phenol -OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C-H⋯F inter-actions generate R 2 (2)(22) loops. PMID:26396909

  18. Spectroscopic and structural study of some 2,5-hexanedione bis(salicyloylhydrazone) complexes: Crystal structures of its Ni(II) and Cu(II) complexes and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxy-benzamide

    NASA Astrophysics Data System (ADS)

    Jeragh, Bakir; El-Asmy, Ahmed A.

    2014-08-01

    The reaction between 2,5-hexanedione and salicylic acid hydrazide produced two compounds: 2,5-hexanedione bis(salicyloylhydrazone) [HDSH] (ethanol insoluble) and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide [DPH] (ethanol soluble). HDSH formed complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and Pd(II) which are characterized by elemental analyses, spectra (IR, 1H NMR, ESR and MS), thermal and magnetic measurements. The crystals of [Ni(HDSH-2H)(EtOH)(H2O)] and [Cu(HDSH-2H)] were solved having octahedral and square-planar geometries, respectively. The other complexes have the formulae [Co(HDSH-2H)(H2O)2], [Cu(HDSH-H)2], [Zn(HDSH-2H)(H2O)2], [Cd2(HDSH-4H)(H2O)4], [Cd2(HDSH-2H)(H2O)4Cl2]; [Hg(HDSH-2H)] and [Pd2(HDSH-4H)(H2O)4]. The obtained complexes are stable in air and non-hygroscopic. The magnetic moments and electronic spectra of the complexes provide different geometries. The ESR spectra support the mononuclear geometry for [Cu(HDSH-2H)] and [Cu(HDSH-H)2]. The thermal decomposition of the complexes revealed the coordinated waters as well as the end product which is in most cases the metal oxide. The crystal structure of N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide is solved by X-ray technique.

  19. Column solid phase extraction and flame atomic absorption spectrometric determination of manganese(II) and iron(III) ions in water, food and biological samples using 3-(1-methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid on synthesized graphene oxide.

    PubMed

    Pourjavid, Mohammad Reza; Sehat, Ali Akbari; Arabieh, Masoud; Yousefi, Seyed Reza; Hosseini, Majid Haji; Rezaee, Mohammad

    2014-02-01

    A modified, selective, highly sensitive and accurate procedure for the determination of trace amounts of manganese and iron ions is established in the presented work. 3-(1-Methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid (MPPC) and graphene oxide (GO) were used in a glass column as chelating reagent and as adsorbent respectively prior to their determination by flame atomic absorption spectrometry. The adsorption mechanism of titled metals complexes on GO was investigated by using computational chemistry approach based on PM6 semi-empirical potential energy surface (PES). The effect of some parameters including pH, flow rate and volume of sample and type, volume and concentration of eluent, as well as the adsorption capacity of matrix ions on the recovery of Mn(II) and Fe(III) was investigated. The limit of detection was 145 and 162 ng L(-1) for Mn(II) and Fe(III), respectively. Calibration was linear over the range of 0.31-355 μg L(-1) for Mn(II) and 0.34-380 μg L(-1) for Fe(III) ions. The method was successfully applied for the determination of understudied ions in water, food and biological samples. PMID:24411390

  20. A combined experimental and theoretical (DFT and AIM) studies on synthesis, molecular structure, spectroscopic properties and multiple interactions analysis in a novel ethyl-4-[2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate and its dimer.

    PubMed

    Singh, R N; Kumar, Amit; Tiwari, R K; Rawat, Poonam

    2013-08-01

    In the present work, ethyl-4-[2-(thiocarbamoyl)hydrazinylidene]-3,5-dimethyl-1H-pyrrole-2-carboxylate (3) has been synthesized and characterized by (1)H NMR, UV-Vis, FT-IR and Mass spectroscopy. The formation of the compound and its properties have also been evaluated by quantum chemical calculations using DFT, B3LYP functional and 6-31G(d,p) as basis set. The calculated thermodynamic parameters show that the formation of 3 is an exothermic and spontaneous reaction at room temperature. (1)H NMR chemical shifts are calculated using gauge including atomic orbitals (GIAO) approach in DMSO-d6 as solvent. Time dependent density functional theory (TD-DFT) is used to calculate the energy (E), oscillator strength (f) and wavelength absorption maxima (λ(max)) of various electronic transitions and their nature within the molecule. NBO analysis is carried out to investigate the charge transfer or charge delocalization in various intra- and intermolecular interactions of molecular system. The vibrational analysis indicates the formation of dimer in the solid state by intermolecular heteronuclear hydrogen bonding (NH···O). Topological parameters at bond critical points (BCP) are calculated to analyze the strength and nature of various types of intra and intermolecular interactions in dimer by Bader's 'Atoms in molecules' AIM theory in detail. The binding energy of intermolecular multiple interactions is calculated to be 15.54 kcal/mol, using AIM calculation. The local reactivity descriptors such as Fukui functions (f(k)(+),f(k)(-)), local softnesses (s(k)(+),s(k)(-)) and electrophilicity indices (ω(k)(+),ω(k)(-)) analyses are performed to determine the reactive sites within molecule. PMID:23666353

  1. Coordination of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with 2,5-hexanedione bis(thiosemicarbazone), HBTS: Crystal structure of cis-[Pd(HBTS)]Cl2 and 1-(2,5-dimethyl-1H-pyrrol-yl)-thiourea

    NASA Astrophysics Data System (ADS)

    Jeragh, Bakir; El-Asmy, Ahmed A.

    2014-09-01

    Metal complexes of Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pd2+ or Pt2+ with 2,5-hexanedione bis(thiosemicarbazone), HBTS; have been prepared and spectroscopically investigated. The empirical formulae of the complexes were suggested based on the elemental analysis. Single crystal of Pd(II) has been solved to be cis-form of square-planar geometry by the X-ray crystallography. 1H and 13C NMR spectra have been recorded for HBTS, Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) complexes, in DMSO-d6, showing the mode of chelation. The ligand acts as a neutral or a binegative tetradentate (N2S2) or neutral bidentate on the basis of FT-IR. The magnetic moments and electronic spectra provide information about the geometry of the complexes which supported by calculating the ligand field parameters for the Co(II) and Fe(III) complexes. The Ni(II) complex has subnormal magnetic moment (0.71 BM) indicative of a mixed stereochemistry of square-planar and tetrahedral structure. [Cu(HBTS-2H)] measured 0.93 BM indicating high interaction between the copper centers. The ligand may be ordered at the top of the spectrochemical series which giving high ligand field splitting energy (10Dq = 17,900 cm-1 for Co2+ complex). The mass spectra of some complexes proved their stable chemical formulae while the TGA depicts the degradation steps and the final residue. In evaporating the mother liquor during the preparation of HBTS, new compound is obtained naming 1-(2,5-dimethyl-1H-pyrrol-yl)thiourea and its crystal was solved.

  2. Coordination of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with 2,5-hexanedione bis(thiosemicarbazone), HBTS: crystal structure of cis-[Pd(HBTS)]Cl2 and 1-(2,5-dimethyl-1H-pyrrol-yl)-thiourea.

    PubMed

    Jeragh, Bakir; El-Asmy, Ahmed A

    2014-09-15

    Metal complexes of Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pd2+ or Pt2+ with 2,5-hexanedione bis(thiosemicarbazone), HBTS; have been prepared and spectroscopically investigated. The empirical formulae of the complexes were suggested based on the elemental analysis. Single crystal of Pd(II) has been solved to be cis-form of square-planar geometry by the X-ray crystallography. 1H and 13C NMR spectra have been recorded for HBTS, Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) complexes, in DMSO-d6, showing the mode of chelation. The ligand acts as a neutral or a binegative tetradentate (N2S2) or neutral bidentate on the basis of FT-IR. The magnetic moments and electronic spectra provide information about the geometry of the complexes which supported by calculating the ligand field parameters for the Co(II) and Fe(III) complexes. The Ni(II) complex has subnormal magnetic moment (0.71 BM) indicative of a mixed stereochemistry of square-planar and tetrahedral structure. [Cu(HBTS-2H)] measured 0.93 BM indicating high interaction between the copper centers. The ligand may be ordered at the top of the spectrochemical series which giving high ligand field splitting energy (10 Dq=17,900 cm(-1) for Co2+ complex). The mass spectra of some complexes proved their stable chemical formulae while the TGA depicts the degradation steps and the final residue. In evaporating the mother liquor during the preparation of HBTS, new compound is obtained naming 1-(2,5-dimethyl-1H-pyrrol-yl)thiourea and its crystal was solved. PMID:24813284

  3. Design, synthesis and antistaphylococcal activity of marine pyrrole alkaloid derivatives.

    PubMed

    Rane, Rajesh A; Sahu, Niteshkumar U; Shah, Chetan P; Shah, Nishant K

    2014-06-01

    A novel set of 16 hybrids of bromopyrrole alkaloids with aroyl hydrazone were designed, synthesized and evaluated for antibacterial and antibiofilm activities against methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43866), methicillin-susceptible Staphylococcus aureus (MSSA; ATCC 35556) and Staphylococcus epidermidis (SE, S. epidermidis ATCC 35984). Of the 16 tested hybrids, 14 exhibited equal or superior antibiofilm activity against MSSA and MRSA relative to standard vancomycin. Compound 4m showed highest potency with antibiofilm activity of 0.39 µg/mL and 0.78 µg/mL against MSSA and MRSA, respectively. Thus, this compound could act as a potential lead for further development of new antistaphylococcal drugs. PMID:23663080

  4. High-level ab initio predictions for the ionization energies and heats of formation of five-membered-ring molecules: thiophene, furan, pyrrole, 1,3-cyclopentadiene, and borole, C4H4X/C4H4X+ (X = S, O, NH, CH2, and BH).

    PubMed

    Lo, Po-Kam; Lau, Kai-Chung

    2011-02-10

    The ionization energies (IEs) and heats of formation (ΔH°(f0)/ΔH°(f298)) for thiophene (C(4)H(4)S), furan (C(4)H(4)O), pyrrole (C(4)H(4)NH), 1,3-cyclopentadiene (C(4)H(4)CH(2)), and borole (C(4)H(4)BH) have been calculated by the wave function-based ab initio CCSD(T)/CBS approach, which involves the approximation to the complete basis set (CBS) limit at the coupled-cluster level with single and double excitations plus a quasi-perturbative triple excitation [CCSD(T)]. Where appropriate, the zero-point vibrational energy correction (ZPVE), the core-valence electronic correction (CV), and the scalar relativistic effect (SR) are included in these calculations. The respective CCSD(T)/CBS predictions for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), being 8.888, 8.897, 8.222, and 8.582 eV, are in excellent agreement with the experimental values obtained from previous photoelectron and photoion measurements. The ΔH°(f0)/ΔH°(f298) values for the aforementioned molecules and their corresponding cations have also been predicted by the CCSD(T)/CBS method, and the results are compared with the available experimental data. The comparisons between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2) suggest that the CCSD(T)/CBS procedure is capable of predicting reliable IE values for five-membered-ring molecules with an uncertainty of ±13 meV. In view of the excellent agreements between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), the similar CCSD(T)/CBS IE and ΔH°(f0)/ΔH°(f298) predictions for C(4)H(4)BH, whose thermochemical data are not readily available due to its reactive nature, should constitute a reliable data set. The CCSD(T)/CBS IE(C(4)H(4)BH) value is 8.868 eV, and ΔH°(f0)/ΔH°(f298) values for C(4)H(4)BH and C(4)H(4)BH(+) are 269.5/258.6 and 1125.1/1114.6 kJ/mol, respectively. The highest occupied molecular orbitals

  5. Site-selective nanoscale-polymerization of pyrrole on gold nanoparticles via plasmon induced charge separation

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Furukawa, Y.; Ishida, T.; Yamada, S.

    2016-04-01

    We proposed a nanoscale oxidative polymerization method which enables site-selective deposition on the surface of gold nanoparticles (AuNPs) combined with TiO2 by using plasmon induced charge separation (PICS) under visible-to-near infrared (IR) light irradiation. The method also revealed that the anodic site of PICS was located at the surface of AuNPs.We proposed a nanoscale oxidative polymerization method which enables site-selective deposition on the surface of gold nanoparticles (AuNPs) combined with TiO2 by using plasmon induced charge separation (PICS) under visible-to-near infrared (IR) light irradiation. The method also revealed that the anodic site of PICS was located at the surface of AuNPs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01531j

  6. The polymerization and electrochemical characterization of polypyrrole and polypyrrole/poly(ethylene oxide)pyrrole copolymers

    NASA Astrophysics Data System (ADS)

    Huntoon, Trey William Stevens

    1998-11-01

    The work contained within this document discusses the polymerization and subsequent characterization of Polypyrrole based electrodes for lithium batteries. Polypyrrole and Polypyrrole/polyethyloxy copolymers were compared and contrasted in an attempt to show the superior kinetics of the copolymer electrode. It was found that the diffusion of dopant ions across the electrode and electrolyte interface was increased by on order of magnitude in the copolymer sample. It was also found that the reversibility of the Polypyrrole electrode was greater than that of the copolymer electrode. While the diffusion coefficient of the copolymer electrode was altered to be comparable to that of the transition metal oxide cathodes in production today, the capacity of the copolymer material is still too low to be considered as an alternative cathode material in the lithium battery industry.

  7. Research on interfacial polymerization of pyrrole assist with Span80 system

    NASA Astrophysics Data System (ADS)

    Yang, Q. H.; Tu, Z. Y.; Zhao, N. Y.

    2016-07-01

    With assistance of surfactants, self-assembled Polypyrrole (PPy) film was prepared via oil / water interfacial polymerization. The chemical structure and morphologies of the obtained samples have been characterized by Fourier transform infrared (FT-IR) and Scanning Electron Microscope (SEM), respectively. The electrochemical performance recorded on an electrochemical workstation, mainly includes cyclic voltammetry (CV) tests. The prepared PPy film has its own extremely vesicular structures from results and indicates by using different concentration surfactant Span80. The PPy film prepared 25 °C with 3.32 g/L Span80 (surpass its critical micelle concentration) as a surfactant possess a supernal specific capacitance of 368.18 F/g at a scan rate 50 mV/s in 1 M NaNO3 aqueous solution at.

  8. Characterization of the formation of the pyrrole moiety during clorobiocin and coumermycin A1 biosynthesis.

    PubMed

    Garneau, Sylvie; Dorrestein, Pieter C; Kelleher, Neil L; Walsh, Christopher T

    2005-03-01

    The aminocoumarin antibiotics clorobiocin and coumermycin A(1) target the B subunit of DNA gyrase by presentation of the 5-methyl-pyrrolyl-2-carboxy ester moiety in the ATP-binding site of the enzyme. The pyrrolyl pharmacophore is derived by a four electron oxidation of a prolyl unit while tethered in phosphopantetheinyl thioester linkage to a peptidyl carrier protein (PCP) subunit. l-Proline is selected and activated as l-prolyl-AMP by adenylation domain enzymes (CloN4 and CouN4) and then installed as the thioester on the holo form of the PCP proteins CloN5 and CouN5. Enzymatic oxidation of the prolyl-S-PCP by the flavoprotein dehydrogenase CloN3 can be followed by rapid quench and subsequent electrospray ionization-Fourier transform mass spectrometry analysis of the acyl-S-protein substrate/product mixture to establish that a two-electron oxidized pyrrolinyl-S-enzyme transiently accumulates on the way to the four-electron oxidized, heteroaromatic pyrrolyl-2-carboxy-S-PCP acyl enzyme product. PMID:15723521

  9. [Synthesis and bronchodilator action of 4-(methoxycarbonylalkylsulfinyl)-4-pyrrol carboxylic esters].

    PubMed

    Eiden, F; Grusdt, U

    1989-11-01

    The dihydro-dimethoxyfuran carboxylic ester 3 reacts with different mercaptoalkyl carboxylates to give the carbomethoxyalkylthio-tetrahydrofuran carboxylic esters 4. Methanol elimination of 4 yields the dihydrofuran derivatives 5. 4 and 5 can be oxidized to afford the sulfoxides 6 and the sulfones 7, respectively. 4 reacts with primary amines to give the title compounds 8. Derivatives of 8 can be cyclized to afford the thienopyrroles 11 and 12 as well as the thienopyranopyrrole 14. The mercaptopyrrole carboxylic ester 10 is obtained from 8f by elimination of propenic acid. 8e shows bronchodilatoric activity in low concentration. PMID:2624526

  10. The supramolecular chemistry of thiosemicarbazones derived from pyrrole: a structural view

    NASA Astrophysics Data System (ADS)

    Alonso, Ruben; Bermejo, Elena; Carballo, Rosa; Castiñeiras, Alfonso; Pérez, Teresa

    2002-03-01

    Condensation of 2-formylpyrrole or 2-acetylpyrrole with thiosemicarbazide or with N-methyl-, N-ethyl-, N-phenyl- or (for 2-formylpyrrole) N-dimethylthiosemicarbazide afforded nine thiosemicarbazones that were characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopy and, when possible, X-ray-diffractometric structure analysis. N-H⋯S hydrogen bonds (and N-H⋯O and/or O-H⋯S bonds in the structures with water or DMSO of crystallization) give rise to supramolecular structures that in some cases are probably stabilized by π-π interactions.

  11. Synthesis of Substituted Furan/Pyrrole-3-carboxamides through a Tandem Nucleopalladation and Isocyanate Insertion.

    PubMed

    Rajesh, Manda; Puri, Surendra; Kant, Ruchir; Sridhar Reddy, Maddi

    2016-09-01

    Access to furanyl- and pyrrolyl-3-carboxamides from readily available 3-alkyne-1,2-diols and 1-amino-3-alkyn-2-ols using isocyanate as amido surrogate is demonstrated. The approach constitutes a successful unprecedented combination of heteropalladation and isocyanate insertion, a new avenue for novel amide bond constructions. The mechanism likely involves a 6-membered oxaaminopalladacycle as the key intermediate. PMID:27532221

  12. Synthesis of Coordinatively Unsaturated Tetravalent Actinide Complexes with η(5) Coordination of Pyrrole.

    PubMed

    Batrice, Rami J; Fridman, Natalia; Eisen, Moris S

    2016-03-21

    The synthesis of new actinide complexes utilizing bridged α-alkyl-pyrrolyl ligands is presented. Lithiation of the ligands followed by treatment with 1 equiv of actinide tetrachloride (uranium or thorium) produces the desired complex in good yield. X-ray diffraction studies reveal unique η(5):η(5) coordination of the pyrrolyl moieties; when the nonsterically demanding methylated ligand is used, rapid addition of the lithiated ligand solution to the metal precursor forms a bis-ligated complex that reveals η(5):η(1) coordination as determined by crystallographic analysis. PMID:26950463

  13. A DFT Study of Pyrrole-Isoxazole Derivatives as Chemosensors for Fluoride Anion

    PubMed Central

    Jin, Ruifa; Sun, Weidong; Tang, Shanshan

    2012-01-01

    The interactions between chemosensors, 3-amino-5-(4,5,6,7-tetrahydro-1H-indol-2-yl)isoxazole-4-carboxamide (AIC) derivatives, and different anions (F− Cl−, Br−, AcO−, and H2PO4−) have been theoretically investigated using DFT approaches. It turned out that the unique selectivity of AIC derivatives for F− is ascribed to their ability of deprotonating the host sensors. Frontier molecular orbital (FMO) analyses have shown that the vertical electronic transitions of absorption and emission for the sensing signals are characterized as intramolecular charge transfer (ICT). The study of substituent effects suggests that all the substituted derivatives are expected to be promising candidates for fluoride chemosensors both in UV-vis and fluorescence spectra except for derivative with benzo[d]thieno[3,2-b]thiophene fragment that can serve as ratiometric fluorescent fluoride chemosensor only. PMID:23109833

  14. DNA damage due to perfluorooctane sulfonate based on nano-gold embedded in nano-porous poly-pyrrole film

    NASA Astrophysics Data System (ADS)

    Lu, Liping; Xu, Laihui; Kang, Tianfang; Cheng, Shuiyuan

    2013-11-01

    DNA damage induced from perfluorooctane sulfonate (PFOS) was further developed on a nano-porous bionic interface. The interface was formed by assembling DNA on nano-gold particles which were embedded in a nano-porous overoxidized polypyrrole film (OPPy). Atomic force microscopy, scanning electron microscope and electrochemical investigations indicate that OPPy can be treated to form nano-pore structures. DNA damage due to PFOS was proved using electrochemistry and X-ray photoelectron spectroscopy (XPS) and was investigated by detecting differential pulse voltammetry (DPV) response of methylene blue (MB) which was used as electro-active indicator in the system. The current of MB attenuates obviously after incubation of DNA in PFOS. Moreover, electrochemical impedance spectroscopy (EIS) demonstrates that PFOS weakens DNA charge transport. The tentative binding ratio of PFOS: DNA base pair was obtained by analyzing XPS data of this system.

  15. An amperometric biosensor based on multiwalled carbon nanotube-poly(pyrrole)-horseradish peroxidase nanobiocomposite film for determination of phenol derivatives.

    PubMed

    Korkut, Seyda; Keskinler, Bulent; Erhan, Elif

    2008-09-15

    An amperometric biosensor based on horseradish peroxidase (HRP) and carbon nanotube (CNT)/polypyrrole (PPy) nanobiocomposite film on a gold surface has been developed. The HRP was incorporated into the CNT/PPy nanocomposite matrix in one-step electropolymerization process without the aid of cross-linking agent. Amperometric response was measured as a function of concentration of phenol derivatives, at a fixed bias voltage of -50 mV. Optimization of the experimental parameters was performed with regard to pH and concentration of hydrogen peroxide. The linear range, sensitivity and detection limit of the biosensor were investigated for eighteen phenol derivatives. The sensitivity in the linear range increased in this order: 4-methoxyphenol>2-aminophenol>guaiacol=m-cresol>2-chlorophenol=4-chlorophenol=hydroquinone=pyrocatechol>2,6-dimethoxyphenol>3-chlorophenol>p-cresol>p-benzoquinone=4-acetamidophenol>catechol>phenol=pyrogallol=2,4-dimethylphenol. CNTs was shown to enhance the electron transfer as a mediator and capable to carry higher bioactivity owing to its intensified surface area. The biosensor exhibited low detection limits with a short response time (2s) for the tested phenolics compared to the reported working electrodes. It retained 70% of its initial activity after using for 700 measurements in 1 month. PMID:18761169

  16. New Pyrrole Derivatives with Potent Tubulin Polymerization Inhibiting Activity As Anticancer Agents Including Hedgehog-Dependent Cancer

    PubMed Central

    La Regina, Giuseppe; Bai, Ruoli; Coluccia, Antonio; Famiglini, Valeria; Pelliccia, Sveva; Passacantilli, Sara; Mazzoccoli, Carmela; Ruggieri, Vitalba; Sisinni, Lorenza; Bolognesi, Alessio; Rensen, Whilelmina Maria; Miele, Andrea; Nalli, Marianna; Alfonsi, Romina; Di Marcotullio, Lucia; Gulino, Alberto; Brancale, Andrea; Novellino, Ettore; Dondio, Giulio; Vultaggio, Stefania; Varasi, Mario; Mercurio, Ciro; Hamel, Ernest; Lavia, Patrizia; Silvestri, Romano

    2014-01-01

    We synthesized 3-aroyl-1-arylpyrrole (ARAP) derivatives as potential anticancer agents having different substituents at the pendant 1-phenyl ring. Both the 1-phenyl ring and 3-(3,4,5-trimethoxyphenyl)carbonyl moieties were mandatory to achieve potent inhibition of tubulin polymerization, binding of colchicine to tubulin, and cancer cell growth. ARAP 22 showed strong inhibition of the P-glycoprotein-overexpressing NCI-ADR-RES and Messa/Dx5MDR cell lines. Compounds 22 and 27 suppressed in vitro the Hedgehog signaling pathway, strongly reducing luciferase activity in SAG treated NIH3T3 Shh-Light II cells, and inhibited the growth of medulloblastoma D283 cells at nanomolar concentrations. ARAPs 22 and 27 represent a new potent class of tubulin polymerization and cancer cell growth inhibitors with the potential to inhibit the Hedgehog signaling pathway. PMID:25025991

  17. Enrichment of Pyrrolic Nitrogen by Hole Defects in Nitrogen and Sulfur Co-Doped Graphene Hydrogel for Flexible Supercapacitors.

    PubMed

    Tran, Ngoc Quang; Kang, Bong Kyun; Woo, Moo Hyun; Yoon, Dae Ho

    2016-08-23

    The effect of the doping configuration and concentration of nitrogen (N) and sulfur (S) on the electrochemical performance of 3 D N and S co-doped hole defect graphene hydrogel (NS-HGH) electrodes is investigated. Surprisingly, by introducing a hole defect on the graphene surface, the difference in the doping concentrations of N and S can be used to effectively modulate the electrochemical behavior of the NS-HGH. The hole defects provide a rapid ion diffusion path. Finally, we showed that the intriguing specific capacitance (536 F g(-1) ) of the NS-HGH could enhance the overall performance of the pseudocapacitance and electric double layer capacitance. The rational design of the NS-HGH-based flexible solid state supercapacitor results in not only outstanding electrochemical performance with a maximum energy density of 14.8 Wh kg(-1) and power density of 5.2 KW kg(-1) but also in extraordinary mechanical flexibility and excellent cycle stability. PMID:27460556

  18. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

    EPA Science Inventory

    For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag) and palladium (Pd), nanospheres, nanowires and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4) or hydroxylamine hydro...

  19. Sequence-specific DNA binding by long hairpin pyrrole-imidazole polyamides containing an 8-amino-3,6-dioxaoctanoic acid unit.

    PubMed

    Sawatani, Yoshito; Kashiwazaki, Gengo; Chandran, Anandhakumar; Asamitsu, Sefan; Guo, Chuanxin; Sato, Shinsuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

    2016-08-15

    With the aim of improving aqueous solubility, we designed and synthesized five N-methylpyrrole (Py)-N-methylimidazole (Im) polyamides capable of recognizing 9-bp sequences. Their DNA-binding affinities and sequence specificities were evaluated by SPR and Bind-n-Seq analyses. The design of polyamide 1 was based on a conventional model, with three consecutive Py or Im rings separated by a β-alanine to match the curvature and twist of long DNA helices. Polyamides 2 and 3 contained an 8-amino-3,6-dioxaoctanoic acid (AO) unit, which has previously only been used as a linker within linear Py-Im polyamides or between Py-Im hairpin motifs for tandem hairpin. It is demonstrated herein that AO also functions as a linker element that can extend to 2-bp in hairpin motifs. Notably, although the AO-containing unit can fail to bind the expected sequence, polyamide 4, which has two AO units facing each other in a hairpin form, successfully showed the expected motif and a KD value of 16nM was recorded. Polyamide 5, containing a β-alanine-β-alanine unit instead of the AO of polyamide 2, was synthesized for comparison. The aqueous solubilities and nuclear localization of three of the polyamides were also examined. The results suggest the possibility of applying the AO unit in the core of Py-Im polyamide compounds. PMID:27301681

  20. π-Delocalization and the vibrational spectroscopy of conjugated materials: computational insights on Raman frequency dispersion in thiophene, furan, and pyrrole oligomers.

    PubMed

    Donohoo-Vallett, Paul J; Bragg, Arthur E

    2015-02-26

    The symmetric C═C stretching frequency (ν(Я)) of conjugated polymers and oligomers is a sensitive spectroscopic reporter of molecular structure and material morphologies; however, thorough understanding of how structure affects this frequency is lacking because computational investigations of this relationship have been undertaken with limited approaches. We present a comprehensive computational investigation of the structure-dependent Raman spectroscopy of oligothiophenes, oligofurans, and oligopyrroles in their ground electronic states using density functional theory. We assessed how various functionals (BLYP, B3LYP, BHLYP, and CAM-B3LYP) impact predictions of length-dependent trends in ν(Я). The amount of Hartree-Fock exchange in a functional is critical for accurately treating π-delocalization and polarizability and hence the structure-dependent Raman behavior. BLYP and B3LYP fail to accurately predict trends in ν(Я) with oligomer length because they over-represent delocalization; in contrast, the range-corrected CAM-B3LYP functional produces the same trends observed experimentally for oligomers in solution and in the solid phase. Through comparisons with a simple mechanical model, we demonstrate that the length- and conformation-dependent spectroscopy of oligothiophenes results from a delicate balance between delocalization-induced softening of ν(Я) and the coupling of oscillators that increase ν(Я). These findings are used to address how variations in inter- and intramolecular order impact the Raman spectroscopy of polythiophenes. PMID:25625486

  1. 1-Benzyl-6-phenyl­imino-5-(pyrrol-2-yl­idene)hexa­hydro­pyrimidine-2,4-dione

    PubMed Central

    Tamazyan, Rafael; Ayvazyan, Armen; Martirosyan, Vahan; Avagyan, Kristine; Martirosyan, Ashot

    2008-01-01

    In the title compound, C21H20N4O2, a potential anti-human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor, the pyrrolidine ring adopts an envelope conformation, while the hydrogenated pyrimidine ring adopts a weakly expressed twist conformation. The mol­ecules are connected into infinite chains via N—H⋯O hydrogen bonds. PMID:21201507

  2. Design and Biological Evaluation of Furan/Pyrrole/Thiophene-2-carboxamide Derivatives as Efficient DNA GyraseB Inhibitors of Staphylococcus aureus.

    PubMed

    Janupally, Renuka; Medepi, Bhramam; Brindha Devi, Parthiban; Suryadevara, Priyanka; Jeankumar, Variam Ullas; Kulkarni, Pushkar; Yogeeswari, Perumal; Sriram, Dharmarajan

    2015-10-01

    DNA topoisomerases are well-validated targets in micro-organisms. DNA gyraseB is one of the most important enzymes among them as per their clinical importance. In earlier study, a novel lead 4-((4-(furan-2-carboxamido)phenyl)amino)-4-oxobutanoic acid was identified as inhibitor against DNA gyraseB with an IC50 of 12.88 ± 1.39 μm. Subsequently, analogues of this lead were developed and evaluated through in vitro assays and in vivo studies. Among the 24 analogues, compound 22 was found to be the top hit with an improved DNA gyraseB activity of 5.35 ± 0.61 μm, and the binding affinity of this compound was further ascertained biophysically through differential scanning fluorimetry. The most potent ligand did not show any signs of cardiotoxicity in zebra fish ether-ago-go-related gene, ascertaining the safety profile of this series a breakthrough among the previously reported cardiotoxic gyraseB inhibitors. PMID:25619742

  3. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, T.

    1996-03-26

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by reacting pyrrole in either of two reaction schemes. One such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  4. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, Tilak

    1996-01-01

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  5. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, T.

    1997-02-04

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by reacting pyrrole in either of two reaction schemes. One such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  6. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, T.

    1996-07-16

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by reacting pyrrole in either of two reaction schemes. One such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  7. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, Tilak

    1996-01-01

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a 2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole!, and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  8. Substituted dipyrromethanes and their preparation

    DOEpatents

    Wijesekera, Tilak

    1997-01-01

    New chemical compounds, bis(pyrrol-2-yl)halocarbylmethanes, also known as meso-halocarbyl dipyrromethanes, are made by recting pyrrole in either of two reaction schemes. Once such scheme converts pyrrole through an intermediate, a halocarbyl carbonyl pyrrole, to a [2-(1-hydroxyl-1-hydro-1-halocarbyl)pyrrole], and then converts the latter to the desired halocarbyldipyrromethane; the last step in this scheme is a novel and useful method in itself. The other such sequence converts pyrrole, by reaction with a halocarbyl aldehyde, directly to the desired halocarbyl dipyrromethane.

  9. The application of vinylogous iminium salt derivatives to efficient formal syntheses of the marine akaloids lamellarin G trimethyl ether and ningalin B.

    PubMed

    Gupton, John T; Giglio, Benjamin C; Eaton, James E; Rieck, Elizabeth A; Smith, Kristin L; Keough, Matthew J; Barelli, Peter J; Firich, Lauren T; Hempel, Jonathan E; Smith, Timothy M; Kanters, Rene P F

    2009-05-30

    Studies directed at the synthesis of lamellarin G trimethyl ether and ningalin B via vinylogous iminium salt derivatives are described. The successful strategy relies on the formation of a 2,4-disubstituted pyrrole or a 1,2,3,4-tetrasubstituted pyrrole from a vinylogous iminium salt or vinylogous iminium salt derivative. Subsequent transformations of these highly substituted pyrroles lead to efficient and regiocontrolled formal syntheses of the respective pyrrole containing natural products. PMID:20161334

  10. 1-(2-Hy­droxy­eth­yl)-3-[(2-hy­droxy­eth­yl)amino]-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione

    PubMed Central

    Xie, Zhi-Xiong; Zhao, Sheng-Yin

    2011-01-01

    There are four molecules in the asymmetric unit of the title compound, C16H17N3O4, in which the dihedral angles between the indole ring system and maleimide ring are 4.5 (3), 8.3 (3), 8.4 (2) and 10.4 (2)°. In the crystal, mol­ecules are linked by numerous N—H⋯O and O—H⋯O hydrogen bonds, generating a three-dimensional network. PMID:21754135

  11. Spectral behavior and laser activity of 3-(4‧-dimethylaminophenyl)-1-(1H-pyrrol-2-yl) prop-2-en-1-one (DMAPrP). A new laser dye

    NASA Astrophysics Data System (ADS)

    El-Sayed, Y. S.; El-Daly, S. A.; Gaber, M.

    2010-03-01

    The photophysical properties of DMAPrP have been investigated in different solvents. DMAPrP dye exhibits a large change in dipole-moment upon excitation due to an intramolecular charge transfer interaction. A crystalline solid of DMAPrP give an excimer like emission at 546 nm. The ground and excited state protonation constants of DMAPrP are calculated. DMAPrP acts as good laser dye upon pumping with nitrogen laser in some organic solvents. The laser parameters such as the tuning range, gain coefficient ( α), emission cross section ( σ e) and half-life energy ( E1/2) are also calculated. The photoreactivity and net photochemical quantum yield of DMAPrP in chloromethane solvents are also studied.

  12. [Role of GABA-A receptors in mechanism of psychotropic action of pyrrol[1,2-a][1,4]diazepines studied using drug discrimination technique in Wistar rats].

    PubMed

    Korolev, A O; Kalinina, T S; Volkova, A V; Mokrov, G V; Kudriashov, N V; Voronina, T A

    2014-01-01

    The role of GABA-A receptors in psychotropic effects of pyrrolo[1,2-a][1,4]diazepine derivatives GMAL-24 and GMAL-27 has been studied on an operant method with liquid reinforcement of drug discrimination in male Wistar rats. It is established that, in substitution tests, GMAL-24 (2, 5, 10 mg/kg) and GMAL-27 (2, 5, 10 mg/kg) do not produce interoceptive effects of phenazepam (1 mg/kg) and fail to inhibit interoceptive effects of corasol (20 mg/kg). The obtained results indicate that pyrrolo[1,2-a][1,4]diazepine derivatives do not exhibit GABA-A receptor-positive modulator properties in vivo. PMID:25102727

  13. (1R,3R,3aS,8aR)-4-Oxo-3-phenyl-1-[(1R)-1-phenyl­eth­yl]deca­hydro­cyclo­hepta­[b]pyrrol-1-ium bromide

    PubMed Central

    Rybakov, Victor B.; Belov, Dmitry S.; Lukyanenko, Evgeny R.; Kurkin, Alexander V.; Yurovskaya, Marina A.

    2012-01-01

    The title chiral compound, C23H28NO+·Br−, was obtained from an optically active amino­ethanol precursor. The pyrrolidine heterocycle has an envelope conformation, with the C atom α-positioned with respect to the keto group deviating by 0.570 (6) Å from the mean plane of other atoms. The trans-fused seven-membered ring adopts a pseudo-chair conformation. The two phenyl rings form a dihedral angle of 85.1 (2)°. The cationic center and the bromide anion are connected through an N—H⋯Br hydrogen bond. PMID:22798884

  14. Fabrication of Minerals Substituted Porous Hydroxyapaptite/Poly(3,4-ethylenedioxy pyrrole-co-3,4-ethylenedioxythiophene) Bilayer Coatings on Surgical Grade Stainless Steel and Its Antibacterial and Biological Activities for Orthopedic Applications.

    PubMed

    Subramani, Ramya; Elangomannan, Shinyjoy; Louis, Kavitha; Kannan, Soundarapandian; Gopi, Dhanaraj

    2016-05-18

    Current strategies of bilayer technology have been aimed mainly at the enhancement of bioactivity, mechanical property and corrosion resistance. In the present investigation, the electropolymerization of poly(3,4-ethylenedioxypyrrole-co-3,4-ethylenedioxythiophene) (P(EDOP-co-EDOT)) with various feed ratios of EDOP/EDOT on surgical grade stainless steel (316L SS) and the successive electrodeposition of strontium (Sr(2+)), magnesium (Mg(2+)) and cerium (Ce(3+)) (with 0.05, 0.075 and 0.1 M Ce(3+)) substituted porous hydroxyapatite (M-HA) are successfully combined to produce the bioactive and corrosion resistance P(EDOP-co-EDOT)/M-HA bilayer coatings for orthopedic applications. The existence of as-developed coatings was confirmed by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), proton nuclear magnetic resonance spectroscopy ((1)H NMR), high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray analysis (EDAX) and atomic force microscopy (AFM). Also, the mechanical and thermal behavior of the bilayer coatings were analyzed. The corrosion resistance of the as-developed coatings and also the influence of copolymer (EDOP:EDOT) feed ratio were studied in Ringer's solution by electrochemical techniques. The as-obtained results are in accord with those obtained from the chemical analysis using inductively coupled plasma atomic emission spectrometry (ICP-AES). In addition, the antibacterial activity, in vitro bioactivity, cell viability and cell adhesion tests were performed to substantiate the biocompatibility of P(EDOP-co-EDOT)/M-HA bilayer coatings. On account of these investigations, it is proved that the as-developed bilayer coatings exhibit superior bioactivity and improved corrosion resistance over 316L SS, which is potential for orthopedic applications. PMID:27128574

  15. Antifungal agents. 10. New derivatives of 1-[(aryl)[4-aryl-1H-pyrrol-3-yl]methyl]-1H-imidazole, synthesis, anti-candida activity, and quantitative structure-analysis relationship studies.

    PubMed

    Tafi, Andrea; Costi, Roberta; Botta, Maurizio; Di Santo, Roberto; Corelli, Federico; Massa, Silvio; Ciacci, Andrea; Manetti, Fabrizio; Artico, Marino

    2002-06-20

    The synthesis, anti-Candida activity, and quantitative structure-activity relationship (QSAR) studies of a series of 2,4-dichlorobenzylimidazole derivatives having a phenylpyrrole moiety (related to the antibiotic pyrrolnitrin) in the alpha-position are reported. A number of substituents on the phenyl ring, ranging from hydrophobic (tert-butyl, phenyl, or 1-pyrrolyl moiety) to basic (NH(2)), polar (CF(3), CN, SCH(3), NO(2)), or hydrogen bond donors and acceptor (OH) groups, were chosen to better understand the interaction of these compounds with cytochrome P450 14-alpha-lanosterol demethylase (P450(14DM)). Finally, the triazole counterpart of one of the imidazole compounds was synthesized and tested to investigate influence of the heterocyclic ring on biological activity. The in vitro antifungal activities of the newly synthesized azoles 10p-v,x-c' were tested against Candida albicans and Candida spp. at pH 7.2 and pH 5.6. A CoMFA model, previously derived for a series of antifungal agents belonging to chemically diverse families related to bifonazole, was applied to the new products. Because the results produced by this approach were not encouraging, Catalyst software was chosen to perform a new 3D-QSAR study. Catalyst was preferred this time because of the possibility of considering each compound as a collection of energetically reasonable conformations and of considering alternative stereoisomers. The pharmacophore model developed by Catalyst, named HYPO1, showed good performances in predicting the biological activity data, although it did not exhibit an unequivocal preference for one enantiomeric series of inhibitors relative to the other. One aromatic nitrogen with a lone pair in the ring plane (mapped by all of the considered compounds) and three aromatic ring features were recognized to have pharmacophoric relevance, whereas neither hydrogen bond acceptor nor hydrophobic features were found. These findings confirmed that the key interaction of azole antifungals with the demethylase enzyme is the coordination bond to the iron ion of the porphyrin system, while interactions with amino acids localized in proximity of heme could modulate the biological activity of diverse antifungal agents. In conclusion, HYPO1 conveys important information in an intuitive manner and can provide predictive capability for evaluating new compounds. PMID:12061875

  16. Chemically modified polypyrrole

    SciTech Connect

    Inagaki, T.; Skotheim, T.A.; Lee, H.S.; Okamoto, Y.; Samuelson, L.; Tripathy, S.

    1988-01-01

    Polypyrrole (PPy) films have been systematically modified with electroactive groups in the ..beta..-position to design electrode materials with specific electrochemical and surface active properties. Electrochemical copolymerization of pyrrole and 3-(6-ferrocenyl,6-hydroxyhexyl)pyrrole (P-6-Fc) yields a ferrocene functionalized polypyrrole with a controlled amount to ferrocene functionalization. And also, copolymers of pyrrole and 3-(4-(2,5- dimethoxyphenyl)butyl)pyrrole (P-MP) can be made by electrochemical polymerization and converted to the copolymers containing pH dependent electroactive hydroquinone moieties. Derivatized pyrroles have also been incorporated into Langmuir-Blodgett film structures. The surface pressure-area isotherms of 3-(13-ferrocenyl,13-hydroxytridecy)pyrrole (P-13-Fc) and the mixed monolayer of P-13-Fc and 3-n-hexadecylpyrrole (HDP) are shown. 17 refs., 4 figs.

  17. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    SciTech Connect

    Nan, Alexandrina Bunge, Alexander; Turcu, Rodica

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  18. Indole derivatives. 129. Reaction of 5-vinylindole with brominating agents

    SciTech Connect

    Starostenko, N.E.; Avdeeva, N.O.; Zeiberlikh, F.N.; Kurkovskaya, L.N.; Suvorov, N.N.

    1987-09-01

    The bromination of 5-vinylindole at two reaction centers, viz., the carbon-carbon multiple bond of the vinyl group and the pyrrole ring, was realized. In the case of the reaction with pyridinium bromide perbromide it was shown that the pyrrole ring is the most reactive with respect to electrophilic agents. It was established that the introduction of an electron-acceptor acetyl group into the pyrrole ring leads to a decrease in the reactivity of the pyrrole ring, and bromination takes place at the double bond.

  19. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    NASA Astrophysics Data System (ADS)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  20. Synthesis of "Meso"-Diethyl-2,2'-Dipyrromethane in Water: An Experiment in Green Organic Chemistry

    ERIC Educational Resources Information Center

    Sobral, Abilio J. F. N.

    2006-01-01

    Dipyrromethanes (or dipyrrilmethanes) are important building blocks for many of the structures of interest in the areas of porphyrins, materials science, optics, and medicine. A variety of conditions have been established for the synthesis of dipyrromethanes of diverse structures, from substituted pyrroles to unsubstituted pyrrole and carbonyl…

  1. Electrically conductive alternating copolymers

    DOEpatents

    Aldissi, M.; Jorgensen, B.S.

    1987-08-31

    Polymers which are soluble in common organic solvents and are electrically conductive, but which also may be synthesized in such a manner that they become nonconductive. Negative ions from the electrolyte used in the electrochemical synthesis of a polymer are incorporated into the polymer during the synthesis and serve as a dopant. A further electrochemical step may be utilized to cause the polymer to be conductive. The monomer repeat unit is comprised of two rings, a pyrrole molecule joined to a thienyl group, or a furyl group, or a phenyl group. The individual groups of the polymers are arranged in an alternating manner. For example, the backbone arrangement of poly(furylpyrrole) is -furan-pyrrole-furan-pyrrole- furan-pyrrole. An alkyl group or phenyl group may be substituted for either or both of the hydrogen atoms of the pyrrole ring.

  2. Methyl 5-ferrocenyl-5a-hydr­oxy-1-methyl-10-oxo-2,3,3a,4,5a,10-hexa­hydro-1H-indeno[1,2:2′,3′]furo[3′,4′-b]pyrrole-3a-carboxyl­ate

    PubMed Central

    Kamala, E. Theboral Sugi; Nirmala, S.; Sudha, L.; Kathiravan, S.; Raghunathan, R.

    2009-01-01

    In the title compound, [Fe(C5H5)(C21H20NO5)], the pyrrolidine and cyclo­penta­none rings exhibit a twist conformation. The pyrrolidine ring is almost perpendicular to the cyclo­penta­none ring, making a dihedral angle of 81.91 (6)°. The mol­ecular conformation is stabilized by an intra­molecular O—H⋯N hydrogen bond and C—H⋯O inter­actions. The crystal structure is stabilized by inter­molecular C—H⋯O inter­actions. PMID:21583045

  3. Note on the choice of basis set in density functional theory calculations for electronic structures of molecules (test on the atoms from the first three rows of the periodic table (2 N Z 18), water, ammonia and pyrrole)

    NASA Astrophysics Data System (ADS)

    Kristyán, Sándor

    1995-12-01

    The effect of basis set in Kohn-Sham theory on estimating correlation energy was investigated using a density functional subroutine and a Hartree-Fock SCF one-electron density program (working with arbitrary basis set). Lee-Yang-Parr density functional estimation, MP2 perturbation calculation and Davidson's accurate configuration interactions calculations for correlation energies of atoms were used for this test. In the density functional estimation a simple 3-21G basis set has produced the same results as the huge triple-zeta basis set with polarization functions within the chemical accuracy (1 kcal/mol).

  4. Chemistry of muconaldehydes of possible relevance to the toxicology of benzene

    SciTech Connect

    Bleasdale, C.; Kennedy, G.; MacGregor, J.O.

    1996-12-01

    (ZZ)-Muconaidehyde reacted with primary amines to give N-substituted-2-(2{prime}-oxoethyl)-pyrroles, which were reduced to 4substituted-2-(2{prime}-hydroxyethyl)-pyrroles by sodium borohydride. The pyrrole-forming reaction is exhibited by valine and its methyl ester, and is being developed with terminal valine in hemoglobin as a means of dose monitoring (ZZ)-muconaldehyde, a putative metabolite of benzene. Reactions in aqueous solution between (ZZ)-muconaldehyde and adenosine, deoxyadenosine, guanosine, or deoxyguanosine leading to pyrrole-containing adducts are described. The elucidation of the structures of the adducts was assisted by the study of reactions between (ZZ)-muconaldehyde and both nucleoside derivatives and a model compound for guanosine. Reactions of (ZZ)-muconaldehyde are complicated by its isomerization to (EZ)- and (EE)-muconaldehyde. The kinetics of this process have been studied in benzene, acetonitrile, and dimethylsulfoxide. 17 refs., 1 tab.

  5. Polumeric electrode coated with reaction product of cyclic compound

    SciTech Connect

    Maxfield, M.; Elsenbaumer, R.L.; Shacklette, L.W.

    1984-09-18

    Batteries are disclosed with electrodes, especially cathodes, having a conjugated backbone polymer such as polyacetylene as electroactive material and a coating. The coating is formed by reaction between the oxidized polymer and a pyrrole, thiophene, azulene, furan or aniline compound.

  6. From dioxime oxalates to dihydropyrroles and phenanthridines via iminyl radicals.

    PubMed

    Portela-Cubillo, Fernando; Scanlan, Eoin M; Scott, Jackie S; Walton, John C

    2008-09-21

    Dioxime oxalates are useful precursors for the clean generation of iminyl radicals by sensitised UV photolysis and can be adapted for serviceable preparations of 3,4-dihydro-2H-pyrroles and phenanthridines. PMID:18802525

  7. Synthetic route to meso-tetra hydrocarbyl or substituted hydrocarbyl porphyrins and derivatives

    DOEpatents

    Wijesekera, T.P.; Wagner, R.W.

    1993-08-31

    The hydroxyl group in a pyrrolic compound having in the 2-position thereof a group having the formula R(OH)CH-R is hydrocarbyl or substituted hydrocarbyl, is replaced by a group, for example a p-nitrobenzoate group, having better leaving properties than those of hydroxyl for a subsequent self-condensation and cyclization of the pyrrolic compound to form a meso-hydrocarbyl or meso-substituted hydrocarbyl porphyrin.

  8. Synthetic route to meso-tetra hydrocarbyl or substituted hydrocarbyl porphyrins and derivatives

    DOEpatents

    Wijesekera, Tilak P.; Wagner, Richard W.

    1993-01-01

    The hydroxyl group in a pyrrolic compound having in the 2-position thereof a group having the formula R(OH)CH--R is hydrocarbyl or substituted hydrocarbyl, is replaced by a group, for example a p-nitrobenzoate group, having better leaving properties than those of hydroxyl for a subsequent self-condensation and cyclization of the pyrrolic compound to form a meso-hydrocarbyl or meso-substituted hydrocarbyl porphyrin.

  9. Biomarkers for ragwort poisoning in horses: identification of protein targets

    PubMed Central

    Moore, Rowan E; Knottenbelt, Derek; Matthews, Jacqueline B; Beynon, Robert J; Whitfield, Phillip D

    2008-01-01

    Background Ingestion of the poisonous weed ragwort (Senecio jacobea) by horses leads to irreversible liver damage. The principal toxins of ragwort are the pyrrolizidine alkaloids that are rapidly metabolised to highly reactive and cytotoxic pyrroles, which can escape into the circulation and bind to proteins. In this study a non-invasive in vitro model system has been developed to investigate whether pyrrole toxins induce specific modifications of equine blood proteins that are detectable by proteomic methods. Results One dimensional gel electrophoresis revealed a significant alteration in the equine plasma protein profile following pyrrole exposure and the formation of a high molecular weight protein aggregate. Using mass spectrometry and confirmation by western blotting the major components of this aggregate were identified as fibrinogen, serum albumin and transferrin. Conclusion These findings demonstrate that pyrrolic metabolites can modify equine plasma proteins. The high molecular weight aggregate may result from extensive inter- and intra-molecular cross-linking of fibrinogen with the pyrrole. This model has the potential to form the basis of a novel proteomic strategy aimed at identifying surrogate protein biomarkers of ragwort exposure in horses and other livestock. PMID:18691403

  10. The application of formyl group activation of bromopyrrole esters to formal syntheses of lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether

    PubMed Central

    Gupton, John T.; Telang, Nakul; Patteson, Jon; Lescalleet, Kristin; Yeudall, Scott; Sobieski, John; Harrison, Andrew; Curry, Will

    2014-01-01

    Lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether are pyrrole containing, natural products, which exhibit interesting biological properties. Such properties include anti-tumor activity on a variety of cancer cell lines including those that confer drug resistance, inhibition of HIV integrase and vascular disrupting activity. We now describe the use of methyl and ethyl 3-bromo-2-formylpyrrole-5-carboxylate as building blocks for the formal synthesis of these three highly functionalized, bioactive pyrroles. These new building blocks will now provide ready access to the natural products and many novel analogs due to the ability to easily modify positions 2,3,4 and 5 of the pyrrole core. PMID:25584014

  11. Permeability improvements of electropolymerized polypyrrole films using dissolvable nano-CaCO3 particle templates.

    PubMed

    Popescu Mandoc, Luisa-Roxana; Gorgy, Karine; Ungureanu, Eleonora-Mihaela; Buica, George-Octavian; Holzinger, Michael; Cosnier, Serge

    2014-03-21

    The electropolymerisation of N-substituted pyrroles on a dissolvable calcium carbonate nanoparticle template was investigated in order to improve the film permeabilities in aqueous solution. After deposition of CaCO3 nanoparticles on the electrode surface, poly(pyrrole-ammonium) or poly(pyrrole-NTA) (NTA: nitrilotriacetic acid) were electrogenerated around the template structures of the electrodes using potentiostatic methods. The dissolution of nanoparticles in acidic medium leads to the formation of nano-porous structures increasing, therefore, the polypyrrole permeability in aqueous solutions. Histidine-tagged glucose oxidase, chosen as an enzyme model, was immobilised on the modified polypyrrole-NTA via the NTA-Cu(2+)-histidine interactions to validate the proposed method. The described setup led to a twofold increase in the maximum current density from 5 to 10 μA cm(-2) after template dissolution. PMID:24481549

  12. Influence of cobalt on fermentative methylation.

    PubMed

    Claridge, C A; Rossomano, V Z; Buono, N S; Gourevitch, A; Lein, J

    1966-03-01

    Streptomyces rishiriensis produces at least five closely related antibiotics. Strain selection yielded a culture producing only the most active component, coumermycin A. Hydrolysis of this antibiotic by barium hydroxide yielded both 5-methyl-pyrrole-2-carboxylic acid and pyrrole-2-carboxylic acid, which could be separated by paper chromatography. Coumermycin A was thus shown to be two fractions, designated A(1) and A(2) depending upon the nature of the pyrrole carboxylic acid portion. The addition of cobalt to the fermentation medium at a level as low as 0.01 mug/ml shifted the fermentation exclusively to the production of coumermycin A(1). Other ions were ineffective, except nickel, whose activity could be explained by the presence of contaminating cobalt. PMID:5959861

  13. A theoretical study on CO2 inserting into Csbnd H bond

    NASA Astrophysics Data System (ADS)

    Ma, Fang; Miao, Tao; Zhou, Zhong-Jun; Xu, Hong-Liang

    2016-03-01

    Density functional theory (DFT) and second-order Møller-Plesset theory (MP2) have been employed to investigate CO2 inserting into Csbnd H bond, where CO2 is in the form of an anion CO2-. The reaction begins with CO2 fixing on the pyrrole to produce ion-complex I via Csbnd C bond formation between the carbon atom of pyrrole and the carbon atom of CO2. Subsequent re-aromatization by dehydrogenation or hydrogen migration, furnishes electron-molecule compounds III, which release the excess electron to produce pyrrole-carboxylic acid. The Csbnd H bond activation and the formation of an extended π-orbital network play important roles in the re-aromatization process.

  14. Antimicrobial activity of secondary metabolites from Streptomyces sp. K15, an endophyte in Houttuynia cordata Thunb.

    PubMed

    Chen, Huabao; Yang, Chunping; Ke, Tao; Zhou, Miaomiao; Li, Zhaojun; Zhang, Min; Gong, Guoshu; Hou, Taiping

    2015-01-01

    We isolated Streptomyces sp. K15 from the root tissue of Houttuynia cordata Thunb and found that some of its secondary metabolites exhibited significant antimicrobial activity against Botrytis cinerea. Moreover, we separated, purified and identified the major active ingredient to be 2-pyrrol formic acid by using silica gel column chromatography, high-performance liquid chromatography and NMR analysis of the spectral data. 2-Pyrrol formic acid critically inhibited the growth of some phytopathogenic bacteria. Therefore, it has potential value in agricultural applications. PMID:25675117

  15. A new conducting nanocomposite -- PPy-zirconium (IV) oxide

    SciTech Connect

    Bhattacharya, A.; De, A.; Sarkar, S.; Ganguly, K.M.

    1996-05-01

    Pyrrole was polymerized in the presence of ultrafine zirconium (IV) oxide (ZrO{sub 2}) particles which act as a dispersant for pyrrole. Room temperature conductivities of the resulting polypyrrole-zirconium (IV) oxide nanocomposites having different ZrO{sub 2} particle concentrations were measured and were compared with that of bare polypyrrole. It was observed that the conductivities of the nanocomposites were higher than that of the polypyrrole without ZrO{sub 2} and increased with ZrO{sub 2} concentration up to a certain limit. From transmission electron microscope studies, particle size and morphology of the nanocomposites and ZrO{sub 2} particles were obtained.

  16. Organic heterocyclic molecules become superalkalis.

    PubMed

    Reddy, G Naaresh; Giri, Santanab

    2016-09-21

    An organic molecule which behaves like a superalkali has been designed from an aromatic heterocyclic molecule, pyrrole. Using first-principles calculation and a systematic two-step approach, we can have superalkali molecules with a low ionization energy, even lower than that of Cs. Couple cluster (CCSD) calculation reveals that a new heterocycle, C3N2(CH3)5 derived from a well-known aromatic heterocycle, pyrrole (C4H5N) has an ionization energy close to 3.0 eV. A molecular dynamics calculation on C3N2(CH3)5 reveals that the structure is dynamically stable. PMID:27530344

  17. Formation of Electrically Conducting Polypyrrole Fine Lines in Arachidic Acid Langmuir-Blodgett Films

    NASA Astrophysics Data System (ADS)

    Sha, Seimei; Hirata, Nobuaki; Ikezaki, Kazuo; Kaihatu, Minoru; Moriizumi, Toyosaka

    1995-07-01

    A new method is proposed for preparing electrically conducting fine lines in Langmuir-Blodgett films: during transference of arachidic acid L film containing pyrrole monomers to an indium-tin-oxide (ITO)-coated glass substrate, a voltage was applied between the ITO and the platinum counterelectrode dipped in the water subphase. From microscopic observations and conductivity measurements, it was confirmed that conducting filaments of polypyrrole were formed by this new method along the contact line between the substrate and the water surface by electrochemical polymerization of pyrrole monomers in an arachidic L film.

  18. Ship in a breakable bottle: fluoride-induced release of an organic molecule from a Pr(iii)-linked molecular cage.

    PubMed

    Lee, Juhoon; Waggoner, Nolan W; Polanco, Luis; You, Ga Rim; Lynch, Vincent M; Kim, Sung Kuk; Humphrey, Simon M; Sessler, Jonathan L

    2016-06-30

    A 3-dimensional networked molecular cage, , has been synthesized. This macrocycle-based framework was prepared from a solvothermal reaction involving a flexible organic building block, calix[4]pyrrole dibenzoic acid (H2), and Pr(NO3)3·6H2O. A unique feature of is that it retains free calix[4]pyrrole molecules in the framework pores. Treatment with a fluoride anion source serves to destroy the network and allows release of the organic guest. The net result is a 'molecular ship' in a 'breakable bottle'. PMID:27273123

  19. Nitrated metalloporphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, Jr., Paul E.; Lyons, James E.

    1994-01-01

    Compositions of matter comprising nitro-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has nitro groups attached thereto in meso and/or .beta.-pyrrolic positions.

  20. Cyano- and polycyanometallo-porphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, P.E. Jr.; Lyons, J.E.

    1993-05-18

    New compositions of matter comprising cyano-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has cyano groups attached thereto in meso- and/or [beta]-pyrrolic positions.

  1. Cyano- and polycyanometallo-porphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, Jr., Paul E.; Lyons, James E.

    1993-01-01

    New compositions of matter comprising cyano-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has cyano groups attached thereto in meso and/or .beta.-pyrrolic positions.

  2. Cyano- and polycyanometallo-porphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, P.E. Jr.; Lyons, J.E.

    1995-01-17

    New compositions of matter comprising cyano-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has cyano groups attached thereto in meso and/or [beta]-pyrrolic positions.

  3. Cyano- and polycyanometallo-porphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, Jr., Paul E.; Lyons, James E.

    1995-01-01

    New compositions of matter comprising cyano-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has cyano groups attached thereto in meso and/or .beta.-pyrrolic positions.

  4. Synthesis and use of a trifluoromethylated azomethine ylide precursor.

    PubMed

    Tran, Gaël; Meier, Robin; Harris, Lawrence; Browne, Duncan L; Ley, Steven V

    2012-12-21

    The presence of fluorous substituents can impart a dramatic effect on the efficacy of molecules used for a range of applications in society. Here, we describe the preparation and use of a new trifluoromethylated azomethine ylide precursor, which leads to a series of fluorinated pyrrolidine, 3-pyrroline, and pyrrole building blocks. PMID:23176732

  5. Solvent-dependent dual-mode photochromism between T- and P-types in a dipyrrinone derivative.

    PubMed

    Sakata, Yoko; Fukushima, Satomi; Akine, Shigehisa; Setsune, Jun-ichiro

    2016-01-21

    A newly synthesized dipyrrinone derivative bearing an ethoxycarbonyl group at the pyrrolic-α position exhibited solvent-dependent dual-mode photochromism between T- and P-types. While this molecule underwent thermally reversible (T-type) photoresponsive reaction in chloroform, it became a thermally irreversible (P-type) system in methanol. PMID:26615770

  6. Design and synthesis of novel, conformationally restricted HMG-CoA reductase inhibitors.

    PubMed

    Pfefferkorn, Jeffrey A; Choi, Chulho; Song, Yuntao; Trivedi, Bharat K; Larsen, Scott D; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Sekerke, Catherine; Auerbach, Bruce; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole

    2007-08-15

    Using structure-based design, a novel series of conformationally restricted, pyrrole-based inhibitors of HMG-CoA reductase were discovered. Leading analogs demonstrated potent inhibition of cholesterol synthesis in both in vitro and in vivo models and may be useful for the treatment of hypercholesterolemia and related lipid disorders. PMID:17574411

  7. Ion-Free and Ion-Pairing Assemblies of Anion-Responsive π-Electronic Systems Possessing Directly Linked Alkyl Chains.

    PubMed

    Haketa, Yohei; Katayama, Daisuke; Fukunaga, Shinya; Bando, Yuya; Sakurai, Tsuneaki; Matsuda, Wakana; Seki, Shu; Maeda, Hiromitsu

    2016-07-20

    Alkyl-substituted pyrrole-based anion-responsive π-electronic systems formed supramolecular gels and liquid crystals through effective π-π stacking and van der Waals interactions. The addition of chloride as a planar cation salt afforded ion-pairing assemblies as soft materials comprising planar receptor-Cl(-) complexes and the cation. PMID:27304212

  8. 27 CFR 21.98 - Bone oil (Dipple's oil).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Bone oil (Dipple's oil....98 Bone oil (Dipple's oil). (a) Color. The color shall be a deep brown. (b) Distillation range. When... below 90 °C. (c) Pyrrol reaction. Prepare a 1.0 percent solution of bone oil in 95 percent...

  9. 27 CFR 21.98 - Bone oil (Dipple's oil).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bone oil (Dipple's oil....98 Bone oil (Dipple's oil). (a) Color. The color shall be a deep brown. (b) Distillation range. When... below 90 °C. (c) Pyrrol reaction. Prepare a 1.0 percent solution of bone oil in 95 percent...

  10. 27 CFR 21.98 - Bone oil (Dipple's oil).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Bone oil (Dipple's oil....98 Bone oil (Dipple's oil). (a) Color. The color shall be a deep brown. (b) Distillation range. When... below 90 °C. (c) Pyrrol reaction. Prepare a 1.0 percent solution of bone oil in 95 percent...

  11. 27 CFR 21.98 - Bone oil (Dipple's oil).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Bone oil (Dipple's oil....98 Bone oil (Dipple's oil). (a) Color. The color shall be a deep brown. (b) Distillation range. When... below 90 °C. (c) Pyrrol reaction. Prepare a 1.0 percent solution of bone oil in 95 percent...

  12. Syntheses of Cyclic Guanidine-Containing Natural Products

    PubMed Central

    Ma, Yuyong; De, Saptarshi; Chen, Chuo

    2014-01-01

    Naturally occurring guanidine derivatives frequently display medicinally useful properties. Among them, the higher order pyrrole-imidazole alkaloids, the dragmacidins, the crambescidins/batzelladines, and the saxitoxins/tetradotoxins have stimulated the development of many new synthetic methods over the past decades. We provide here an overview of the syntheses of these cyclic guanidine-containing natural products. PMID:25684829

  13. Investigating the Mechanism of Heteroaromatic Decarboxylation Using Solvent Kinetic Isotope Effects and Eyring Transition-State Theory

    ERIC Educational Resources Information Center

    Mundle, Scott O. C.; Opinska, Liliana Guevara; Kluger, Ronald; Dicks, Andrew P.

    2011-01-01

    An upper-level mechanistic organic experiment is outlined where undergraduates measure kinetic rate constants for decarboxylation of pyrrole-2-carboxylic acid by the initial-rates method. UV spectroscopy is used to monitor reactant disappearance in both hydrochloric acid and deuterium chloride at different temperatures. Individual data are pooled…

  14. Silver(I)- or copper(II)-mediated dearomatization of aromatic ynones: direct access to spirocyclic scaffolds.

    PubMed

    James, Michael J; Cuthbertson, James D; O'Brien, Peter; Taylor, Richard J K; Unsworth, William P

    2015-06-22

    A high-yielding silver(I)- or copper(II)-catalyzed dearomatizing spirocyclization strategy allows the conversion of simple aromatic compounds that contain ynone substituents, including indole, anisole, pyrrole, and benzofuran derivatives, into functionalized spirocyclic scaffolds. A high-yielding asymmetric variant furnishes spirocyclic indolenines in up to 89:11 e.r. PMID:25960013

  15. Efficacy of chlorfenapyr against Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) adults exposed on concrete, vinyl tile, and plywood surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The insecticidal pyrrol chlorfenapyr was applied to concrete, tile, and wood surfaces, at an application rate of 0.11 mgAI/cm2. Adult Tribolium castaneum (Herbst), the red flour beetle, and adult T. confusum (DuVal), the confused flour beetle, were exposed for 2 and 4 hours, removed, and held witho...

  16. Efficacy of chlorfenapyr against Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) adults exposed on concrete, vinyl tile, and plywood surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The insecticidal pyrrol chlorfenapyr was applied to concrete, tile, and wood surfaces, at an application rate of 0.11mg AI/cm2. Adult Tribolium castaneum (Herbst), the red flour beetle, and adult T. confusum (DuVal), the confused flour beetle, were exposed for 2 and 4 hours, removed, and held witho...

  17. Molecular structures and absorption spectra assignment of corrole NH tautomers.

    PubMed

    Beenken, Wichard; Presselt, Martin; Ngo, Thien H; Dehaen, Wim; Maes, Wouter; Kruk, Mikalai

    2014-02-01

    The individual absorption spectra of the two NH tautomers of 10-(4,6-dichloropyrimidin-5-yl)-5,15-dimesitylcorrole are assigned on the basis of the Gouterman four-orbital model and a quantum chemical TD-DFT study. The assignment indicates that the red-shifted T1 tautomer is the one with protonated pyrrole nitrogen atoms N(21), N(22) and N(23), whereas the blue-shifted T2 tautomer has pyrrole nitrogen atoms N(21), N(22) and N(24) protonated. A wave-like nonplanar distortion of the macrocycle in the ground state is found for both NH tautomers, with the wave axis going through the pyrroles containing N(22) and N(24). The 7C plane determined by the least-squares distances to the carbon atoms C1, C4, C5, C6, C9, C16, and C19 is suggested as a mean corrole macrocycle plane for the analysis of out-of-plane distortions. The magnitude of these distortions is distinctly different for the two NH tautomers, leading to substantial perturbations of their acid-base properties, which are rationalized by the interplay of the degree of out-of-plane distortion of the macrocycle as a whole and the tendency of the pyrrole nitrogen atoms toward pyramidalization, with the former leading to a basicity increase whereas the latter enhances the acidity. PMID:24432802

  18. Response to Comment on “Asymmetric syntheses of sceptrin and massadine and evidence for biosynthetic enantiodivergence”

    PubMed Central

    Ma, Zhiqiang; Wang, Xiaolei; Wang, Xiao; Rodriguez, Rodrigo A.; Moore, Curtis E.; Gao, Shuanhu; Tan, Xianghui; Ma, Yuyong; Rheingold, Arnold L.; Baran, Phil S.; Chen, Chuo

    2015-01-01

    Sherman et al. commented on the precedence of enantiodivergence, listing a number of congeneric natural products with opposite chirality. However, these “congeners” are not derived from enantiodivergent biosyntheses. Instead, they are antipodes arising from separate enantiomeric biosyntheses. A distinct feature of the biosynthesis of the cyclic pyrrole-imidazole dimers is the production of antipodal congeners without the corresponding enantiomers. PMID:26160939

  19. C-H functionalization of cyclic amines: redox-annulations with α,β-unsaturated carbonyl compounds.

    PubMed

    Kang, YoungKu; Richers, Matthew T; Sawicki, Conrad H; Seidel, Daniel

    2015-07-01

    Cyclic amines such as pyrrolidine and 1,2,3,4-tetrahydroisoquinoline undergo redox-annulations with α,β-unsaturated aldehydes and ketones. Carboxylic acid promoted generation of a conjugated azomethine ylide is followed by 6π-electrocylization, and, in some cases, tautomerization. The resulting ring-fused pyrrolines are readily oxidized to the corresponding pyrroles or reduced to pyrrolidines. PMID:26051897

  20. Asymmetric Total Synthesis of (+)-Ryanodol and (+)-Ryanodine.

    PubMed

    Masuda, Kengo; Koshimizu, Masaki; Nagatomo, Masanori; Inoue, Masayuki

    2016-01-01

    (+)-Ryanodine (1) is the ester derivative of 1H-pyrrole-2-carboxylic acid and the complex terpenoid (+)-ryanodol (2), which possesses eleven contiguous stereogenic centers on the ABCDE-ring system. Compound 1 is known to be a potent modulator of intracellular calcium release channels, whereas the activity of 2 is significantly weaker. To chemically construct 1, the multiple oxygen functional groups must be installed on the fused pentacycle in stereoselective fashions and the extremely hindered C3-hydroxy group must be acylated in a site-selective manner. First, the total synthesis of 2 was accomplished by introducing the five stereocenters from the previously prepared enantiopure ABDE-ring 7. Stereoselective construction of the C3-secondary, C2- and C6-tertiary alcohols was achieved by three nucleophilic reactions. The C9- and C10-trisubstituted carbon centers were regio- and stereoselectively introduced by hydroboration/oxidation of the six-membered C-ring, which was formed by the ring-closing metathesis reaction. Direct esterification of the C3-alcohol with pyrrole-2-carboxylic acid proved unsuccessful; therefore, we developed a new, two-step protocol for attachment of the pyrrole moiety. The C3-hydroxy group was first converted into the less sterically cumbersome glycine ester, which was then transformed into the pyrrole ring through condensation with 1,3-bis(dimethylamino)allylium tetrafluoroborate. This procedure resulted in the first total synthesis of 1. PMID:26616265

  1. Draft genome sequence of Streptomyces vitaminophilus ATCC 31673, a producer of pyrrolomycin antibiotics, some of which contain a nitro group

    DOE PAGESBeta

    Mahan, Kristina M.; Klingeman, Dawn Marie; Robert L. Hettich; Parry, Ronald J.; Graham, David E.

    2016-01-21

    Streptomyces vitaminophilus produces pyrrolomycins, which are halogenated polyketide antibiotics. Some of the pyrrolomycins contain a rare nitro group located on the pyrrole ring. In addition, the 6.5-Mbp genome encodes 5,941 predicted protein-coding sequences in 39 contigs with a 71.9% G+C content.

  2. Boc Groups as Protectors and Directors for Ir-Catalyzed C–H Borylation of Heterocycles

    PubMed Central

    Kallepalli, Venkata A.; Shi, Feng; Paul, Sulagna; Onyeozili, Edith N.; Maleczka, Robert E.; Smith, Milton R.

    2013-01-01

    Ir-catalyzed C–H borylation is found to be compatible with Boc protecting groups. Thus, pyrroles, indoles, and azaindoles can be selectively functionalized at C–H positions β to N. The Boc group can be removed on thermolysis or left intact during subsequent transformations. PMID:19894699

  3. Nonaqueous polypyrrole colloids

    DOEpatents

    Armes, Steven P.; Aldissi, Mahmoud

    1991-01-01

    Processable conductive polymers including an oxidized, polymerized aromatic heterocyclic monomer, e.g., pyrrole, an stabilizing effective amount of a poly(vinyl acetate) and dopant anions, and a process of preparing said processable conductive polymers directly in a nonaqueous medium such as methyl acetate, methyl formate, ethyl formate, and propyl formate are disclosed.

  4. Synthesis of new unsaturated mesotetraarylporphyrins

    SciTech Connect

    Zhamkochyan, G.A.; Akopyan, M.E.; Akopyan, L.M.; Kurtikyan, T.S.

    1987-08-01

    A method has been developed for the preparation of tetra(4'-vinylphenyl)porphyrin by the condensation of 4-..beta..-halogenethylbenzaldehyde with pyrrole and dehydrohalogenation of the obtained tetra(4'-halogenethylphenyl)porphyrins. The composition and structure of the obtained porphyrins was confirmed by elemental analysis and by electron, IR, and PMR spectra.

  5. Microwave-promoted, metal- and catalyst-free decarboxylative α,β-difunctionlization of secondary α-amino acids via pseudo-four-component reactions.

    PubMed

    Manjappa, Kiran B; Jhang, Wei-Fang; Huang, Shin-Yi; Yang, Ding-Yah

    2014-11-01

    A microwave-promoted, metal- and catalyst-free decarboxylative α,β-difunctionlization of secondary α-amino acids via a pseudo-four-component coupling of proline, aldehyde, and 1,3-diketone to generate multifunctionalized pyrano[2,3-b]pyrrole and pyrrolizinone derivatives is reported. PMID:25343174

  6. A possible prebiotic origin on volcanic islands of oligopyrrole-type photopigments and electron transfer cofactors.

    PubMed

    Fox, Stefan; Strasdeit, Henry

    2013-06-01

    Tetrapyrroles are essential to basic biochemical processes such as electron transfer and photosynthesis. However, it is not known whether these evolutionary old molecules have a prebiotic origin. We have serendipitously obtained pyrroles, which are the corresponding monomers, in laboratory experiments that simulated the interaction of amino acid-containing seawater with molten lava. The thermal pyrrole formation from amino acids, which so far has only been reported for special cases, can be explained by the observation that the amino acids become metal bonded, for example in (CaCl2)3(Hala)2·6H2O (Hala=DL-alanine), when the seawater evaporates. At a few hundred degrees Celsius, sea salt crusts also release hydrochloric acid (HCl). On primordial volcanic islands, the volatile pyrroles and HCl must have condensed at cooler locations, for example, in rock pools. There, pyrrole oligomerization may have occurred. To study this possibility, we added formaldehyde and nitrite, two species for which plausible prebiotic sources are known, to 2,4-diethylpyrrole and HCl. We found that even at high dilution conjugated (oxidized) oligomers, including octaethylporphyrin and other cyclic and open-chain tetrapyrroles, were formed. All experiments were conducted under rigorously oxygen-free conditions. Our results suggest that primitive versions of present-day biological cofactors such as chlorophylls, bilins, and heme were spontaneously abiotically synthesized on primordial volcanic islands and thus may have been available to the first protocells. PMID:23742230

  7. Ageladine A: an antiangiogenic matrixmetalloproteinase inhibitor from the marine sponge Agelas nakamurai.

    PubMed

    Fujita, Masaki; Nakao, Yoichi; Matsunaga, Shigeki; Seiki, Motoharu; Itoh, Yoshifumi; Yamashita, Jun; Van Soest, Rob W M; Fusetani, Nobuhiro

    2003-12-24

    A novel MMP inhibitor, ageladine A (1) with antiangiogenic activity was isolated from a marine sponge Agelas nakamurai. Structure 1 was determined by a combination of spectroscopic and chemical methods to be an unprecedented structure of 4-(4,5-dibromo-1H-pyrrol-2-yl)]-1H-imidazo[4,5-c]pyridin-2-amine. PMID:14677933

  8. Near-infrared-induced electron transfer of an uranyl macrocyclic complex without energy transfer to dioxygen.

    PubMed

    Davis, Christina M; Ohkubo, Kei; Ho, I-Ting; Zhang, Zhan; Ishida, Masatoshi; Fang, Yuanyuan; Lynch, Vincent M; Kadish, Karl M; Sessler, Jonathan L; Fukuzumi, Shunichi

    2015-04-21

    Photoexcitation of dichloromethane solutions of an uranyl macrocyclic complex with cyclo[1]furan[1]pyridine[4]-pyrrole () at the near-infrared (NIR) band (1177 nm) in the presence of electron donors and acceptors resulted in NIR-induced electron transfer without producing singlet oxygen via energy transfer. PMID:25791126

  9. 5-Bromo-1H-pyrrolo-[2,3-b]pyridine.

    PubMed

    Starha, Pavel; Trávníček, Zdeněk

    2013-03-01

    In the title compound, C7H5BrN2, fused six-membered pyridine and five-membered pyrrole rings form the essentially planar aza-indole skeleton (r.m.s. deviation = 0.017 Å). In the crystal, pairs of N-H⋯N hydrogen bonds connect the mol-ecules into inversion dimers. PMID:23476567

  10. Efficacy of chlorfenapyr against adult Tribolium castaneum exposed on concrete: effects of exposure interval, concentration, and the presence of a food source after exposure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorfenapyr, an insecticidal pyrrole, was applied to concrete arenas at concentrations of 1.1, 0.825, 0.55, and 0.275 g of active ingredient m2. Adult Tribolium castaneum (Herbst), the red flour beetle were exposed for 2, 4, or 8 hours at each concentration, then removed and held either with or w...

  11. Nitrated metalloporphyrins as catalysts for alkane oxidation

    DOEpatents

    Ellis, P.E. Jr.; Lyons, J.E.

    1994-01-18

    Compositions of matter comprising nitro-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has nitro groups attached thereto in meso and/or [beta]-pyrrolic positions.

  12. Draft Genome Sequence of Streptomyces vitaminophilus ATCC 31673, a Producer of Pyrrolomycin Antibiotics, Some of Which Contain a Nitro Group

    PubMed Central

    Klingeman, Dawn M.; Hettich, Robert L.; Parry, Ronald J.

    2016-01-01

    Streptomyces vitaminophilus produces pyrrolomycins, which are halogenated polyketide antibiotics. Some of the pyrrolomycins contain a rare nitro group located on the pyrrole ring. The 6.5-Mbp genome encodes 5,941 predicted protein-coding sequences in 39 contigs with a 71.9% G+C content. PMID:26798098

  13. Thermal Extraction–Two-Dimensional Gas Chromatography–Mass Spectrometry with Heart-Cutting for Nitrogen Heterocyclics in Biomass Burning Aerosols

    EPA Science Inventory

    A thermal extraction-two-dimensional gas chromatography-mass spectrometry (TE-GC-MS) method (with heart-cutting) is developed for quantitatively assessing nitrogen (N-bearing organic species (e.g., pyrrole, pyridine, nitriles, and amines) in aerosols emitted from agricultural fir...

  14. Synthetic Approaches to the Lamellarins—A Comprehensive Review

    PubMed Central

    Imbri, Dennis; Tauber, Johannes; Opatz, Till

    2014-01-01

    The present review discusses the known synthetic routes to the lamellarin alkaloids published until 2014. It begins with syntheses of the structurally simpler type-II lamellarins and then focuses on the larger class of the 5,6-saturated and -unsaturated type-I lamellarins. The syntheses are grouped by the strategy employed for the assembly of the central pyrrole ring. PMID:25528958

  15. Transient ions in electron and positron scattering

    NASA Astrophysics Data System (ADS)

    d'A Sanchez, Sergio; de Oliveira, Eliane M.; dos Santos, Josué S.; da Costa, Romarly F.; Bettega, Márcio H. F.; Lima, Marco A. P.; Varella, Márcio T. do N.

    2009-11-01

    We report on recent advances in studies of transient ions formed in electron and positron scattering by molecules. We briefly discuss elastic electron collisions against pyrrole and glycine, as well as electron affinities of glycine-water clusters. Positron scattering and annihilation on small molecules is also discussed.

  16. Preparation of Conducting Polymers by Electrochemical Methods and Demonstration of a Polymer Battery

    ERIC Educational Resources Information Center

    Goto, Hiromasa; Yoneyama, Hiroyuki; Togashi, Fumihiro; Ohta, Reina; Tsujimoto, Akitsu; Kita, Eiji; Ohshima, Ken-ichi

    2008-01-01

    The electrochemical polymerization of aniline and pyrrole, and demonstrations of electrochromism and the polymer battery effect, are presented as demonstrations suitable for high school and introductory chemistry at the university level. These demonstrations promote student interest in the electrochemical preparation of conducting polymers, where…

  17. Preparation of porphyrins and their metal complexes

    DOEpatents

    Ellis, Jr., Paul E.; Langdale, Wayne A.

    1997-01-01

    A hydroxyl-containing pyrrolic compound having a hydroxyl group or a hydroxyl-containing group in the 2-position, optionally substituted in the beta positions, is condensed in an acidified two immiscible phase solvent system to produce excellent yields of the corresponding porphyrin or metal porphyrin.

  18. Preparation of porphyrins and their metal complexes

    DOEpatents

    Ellis, P.E. Jr.; Langdale, W.A.

    1997-08-19

    A hydroxyl-containing pyrrolic compound having a hydroxyl group or a hydroxyl-containing group in the 2-position, optionally substituted in the beta positions, is condensed in an acidified two immiscible phase solvent system to produce excellent yields of the corresponding porphyrin or metal porphyrin.

  19. Synthesis of nitrogen heterocycles via α-aminoalkyl radicals generated from α-silyl secondary amines under visible light irradiation.

    PubMed

    Nakajima, Kazunari; Kitagawa, Mai; Ashida, Yuya; Miyake, Yoshihiro; Nishibayashi, Yoshiaki

    2014-08-18

    We have succeeded in the visible light-mediated synthetic use of α-aminoalkyl radicals derived from α-silyl secondary amines toward addition to α,β-unsaturated carbonyl compounds. The resulting γ-aminocarbonyl compounds are converted into γ-lactams and pyrroles in a one-pot process. PMID:24969854

  20. Ultra-Trace Detection of Fluoride Ion and Hydrofluoric Acid

    SciTech Connect

    Timothy M. Swager

    2005-03-17

    Describes general synthetic strategies developed under this grant to control interchain electronic communications within conjugated polymers (CPs). Novel chemical architectures built on iptycenes, metallorotaxanes, and canopied pyrroles restrict the dimensionality of electronic structures responsible for excition and charge transport. Structure-property relationships emerging from studies of selected systems are discussed, focusing on their implications for the sensitivity of these materials as sensors.

  1. ROOM TEMPERATURE BULK SYNTHESIS OF SILVER NANOCABLES WRAPPED WITH POLYPYRROLE

    EPA Science Inventory

    Wet chemical synthesis of silver cables wrapped with polypyrrole is reported in aqueous media without use of any surfactant/capping agent and/or template. The method employs direct polymerization of pyrrole of an aqueous solution with AgNO3 as an oxidizing agent. The four probe c...

  2. Efficient Quantitative Analysis of Carboxyalkylpyrrole Ethanolamine Phospholipids: Elevated Levels in Sickle Cell Disease Blood.

    PubMed

    Guo, Junhong; Wang, Hua; Hrinczenko, Borys; Salomon, Robert G

    2016-07-18

    γ-Hydroxy-α,β-unsaturated aldehydes, generated by oxidative damage of polyunsaturated phospholipids, form pyrrole derivatives that incorporate the ethanolamine phospholipid (EP) amino group such as 2-pentylpyrrole (PP)-EP and 2-(ω-carboxyalkyl)pyrrole (CAP)-EP derivatives: 2-(ω-carboxyethyl)pyrrole (CEP)-EP, 2-(ω-carboxypropyl)pyrrole (CPP)-EP, and 2-(ω-carboxyheptyl)pyrrole (CHP)-EP. Because EPs occur in vivo in various forms, a complex mixture of pyrrole-modified EPs with different molecular weights is expected to be generated. To provide a sensitive index of oxidative stress, all of the differences in mass related to the glycerophospholipid moieties were removed by releasing a single CAP-ethanolamine (ETN) or PP-ETN from each mixture by treatment with phospholipase D. Accurate quantization was achieved using the corresponding ethanolamine-d4 pyrroles as internal standards. The product mixture obtained by phospholipolysis of total blood phospholipids from sickle cell disease (SCD) patients was analyzed by LC-MS/MS. The method was applied to measure CAP-EP and PP-EP levels in blood plasma from clinical monitoring of SCD patients. We found uniformly elevated blood levels of CEP-EP (63.9 ± 9.7 nM) similar to mean levels in blood from age-related macular degeneration (AMD) patients (56.3 ± 37.1 nM), and 2-fold lower levels (27.6 ± 3.6 nM, n = 5) were detected in plasma from SCD patients hospitalized to treat a sickle cell crisis, although mean levels remain higher than those (12.1 ± 10.5 nM) detected in blood from healthy controls. Plasma levels of CPP-EPs from SCD clinic patients were 4-fold higher than those of SCD patients hospitalized to treat a sickle cell crisis (45.1 ± 10.9 nM, n = 5 versus 10.9 ± 3.4 nM, n = 6; p < 0.002). PP-EP concentration in plasma from SCD clinic patients is nearly 4.8-fold higher than its level in plasma samples from SCD patients hospitalized to treat a sickle cell crisis (7.06 ± 4.05 vs 1.48 ± 0.92 nM; p < 0.05). Because

  3. Molecular structure of cotinine studied by gas electron diffraction combined with theoretical calculations

    NASA Astrophysics Data System (ADS)

    Takeshima, Tsuguhide; Takeuchi, Hiroshi; Egawa, Toru; Konaka, Shigehiro

    2007-09-01

    The molecular structure of cotinine (( S)-1-methyl-5-(3-pyridinyl)-2-pyrrolidinone), the major metabolite of nicotine, has been determined at about 182 °C by gas electron diffraction combined with MP2 and DFT calculations. The diffraction data are consistent with the existence of the (ax, sc), (ax, ap), (eq, sp) and (eq, ap) conformers, where ax and eq indicate the configuration of the pyrrolidinone ring by means of the position (axial and equatorial) of the pyridine ring, and sc, sp and ap distinguish the isomers arising from the internal rotation around the bond connecting the two rings. The (CH 3)NCCC(N) dihedral angles, ϕ, of the (ax, sc) and (eq, sp) conformers were determined independently to be 158(12)° and 129(13)°, respectively, where the numbers in parentheses are three times the standard errors, 3 σ. According to the MP2 calculations, the corresponding dihedral angles for the (ax, ap) and (eq, ap) conformers were assumed to differ by 180° from their syn counterparts. The ratios x(ax, sc)/ x(ax, ap) and x(eq, sp)/ x(eq, ap) were taken from the theoretically estimated free energy differences, Δ G, where x is the abundance of the conformer. The resultant abundances of (ax, sc), (ax, ap), (eq, sp) and (eq, ap) conformers are 34(6)%, 21% (d.p.), 28% (d.p.), and 17% (d.p.), respectively, where d.p. represents dependent parameters. The determined structural parameters ( rg (Å) and ∠ α (°)) of the most abundant conformer, (ax, sc), are as follows: r(N sbnd C) pyrrol = 1.463(5); r(N sbnd C methyl) = 1.457(←); r(N sbnd C( dbnd O)) = 1.384(12); r(C dbnd O) = 1.219(5); < r(C sbnd C) pyrrol> = 1.541(3); r(C pyrrolsbnd C pyrid) = 1.521(←); < r(C sbnd C) pyrid> = 1.396(2); < r(C sbnd N) pyrid> = 1.343(←); ∠(CNC) pyrrol = 113.9(11); ∠CCC pyrrol(-C pyrid) = 103.6(←); ∠NCO = 124.1(13); ∠NC pyrrolC pyrid = 113.1(12); ∠C pyrrolC pyrrolC pyrid = 113.3(←); ∠(CNC) pyrid = 117.1(2); <∠(NCC) pyrid> = 124.4(←); ∠C methylNC( dbnd O) =

  4. NMR Investigation of beta-Substituted High-Spin and Low-Spin Iron(III) Tetraphenylporphyrins.

    PubMed

    Wojaczynski, Jacek; Latos-Grazynski, Lechoslaw; Hrycyk, Witold; Pacholska, Ewa; Rachlewicz, Krystyna; Szterenberg, Ludmila

    1996-11-01

    The NMR spectra of a series of beta-substituted iron(III) tetraphenylporphyrin (2-X-TPP) complexes have been studied to elucidate the relationship between the electron donating/withdrawing properties of the 2-substituent and the (1)H NMR spectral pattern. The electronic nature of the substituent has been significantly varied and covered the -0.6 to 0.8 Hammett constant range. Both high-spin and low-spin complexes of the general formula (2-X-TPP)Fe(III)Cl and [(2-X-TPP)Fe(III)(CN)(2)](-) have been investigated. The (1)H NMR data for the following substituents (X) have been reported: py(+), NO(2), CN, CH(3), BzO (C(6)H(5)COO), H, D, Br, Cl, CH(3), NH(2), NH(3)(+), NHCH(3), OH, and O(-). The (1)H NMR resonances for low-spin dicyano complexes have been completely assigned by a combination of two-dimensional COSY and NOESY experiments. In the case of selected high-spin complexes, the 3-H resonance has been identified by the selective deuteration of all but the 3-H position. The pattern of unambiguously assigned seven pyrrole resonances reflects the asymmetry imposed by 2-substitution and has been used as an unique (1)H NMR spectroscopic probe to map the spin density distribution. The pyrrole isotropic shifts of [(2-X-TPP)Fe(III)(CN)(2)](-) are dominated by the contact term. In order to quantify the substituent effect, the dependence of isotropic shift of all low-spin pyrrole resonances and 3-H high-spin pyrrole resonance versus Hammett constants has been studied. The electronic effect is strongly localized at the beta-substituted pyrrole. The major change of the isotropic shift has also been noted for only one of two adjacent pyrrole rings, i.e., at 7-H and 8-H positions. These neighboring protons, located on a single pyrrole ring, experienced opposite shift changes when electron withdrawing/donating properties were modified. Two other pyrrole rings for all investigated derivatives revealed considerably smaller, substituent related, isotropic shift changes. A long

  5. Alterations in rat axonal cytoskeletal proteins induced by in vitro and in vivo 2,5-hexanedione exposure.

    PubMed

    DeCaprio, A P; O'Neill, E A

    1985-04-01

    The neurotoxic gamma-diketone 2,5-hexanedione (2,5-HD) reacts in vitro and in vivo with protein lysine epsilon-amine moieties to yield 2,5-dimethylpyrrole adducts. It has been hypothesized that pyrrole adduct formation in neurofilament (NF) or other axonal proteins may lead to increased hydrophobicity, secondary autoxidative crosslinking, or the loss of essential lysine amine groups, and that pyrrolylation therefore represents the critical initiating event in gamma-diketone neuropathy. The present investigation was designed to evaluate pyrrole levels and other changes in brain stem and spinal cord axonal cytoskeletal proteins from rats receiving 0.5% 2,5-HD in the drinking water for up to 8 weeks and following recovery. Clinical signs of neuropathy were apparent in rats after 5 weeks exposure, while no histopathological effects were seen until 8 weeks. Cessation of dosing resulted in some recovery from clinical neuropathy but virtually no change in histopathologically demonstrable CNS damage. 2,5-Dimethylpyrrole adduct was detected in serum and axonal cytoskeletal proteins from animals in all exposure groups and its formation appeared to reach a plateau in both serum and axonal protein. Assay of total protein lysine vs pyrrole content demonstrated an average conversion of less than 1% of epsilon-amine groups into pyrrole adducts in axonal protein after 2 weeks exposure. Gel electrophoresis revealed discrete new protein bands in brain stem and spinal cord axonal protein preparations from treated animals, along with high-molecular-weight, nonmigrating proteinaceous material. Concentration of the nonmigrating material appeared to increase in a time-dependent fashion. A concurrent decrease in the relative amounts of native NF subunit proteins was observed in brain stem but not spinal cord. Reversal of these changes was observed 9 weeks after cessation of dosing, although residual nonmigrating protein and pyrrole adduct were present. In vitro incubation of axonal

  6. Efficient synthesis and reactions of 1,2-dipyrrolylethynes

    PubMed Central

    Tanui, Hillary K.; Hao, Erhong; Ihachi, Moses I.; Fronczek, Frank R.; Smith, Kevin M.; Vicente, M. Graça H.

    2011-01-01

    Various dipyrroles possess important motifs for construction of pyrrole-containing pigments. A series of 1,2-dipyrrolylethynes (4a–d) has been efficiently synthesized using an improved one-pot double Sonagashira coupling from trimethylsilylethyne and various 2-iodopyrroles. The resulting 1,2-dipyrrolylethynes were further transformed into novel indolyl-, ethenyl- and carboranyl-dipyrroles (5–7) using the Larock indole synthesis, stereoselective catalytic hydrogenation, or B10H14. Indolyl-dipyrroles were found to selectively bind fluoride ions using one pyrrolic and the indolyl NHs, whereas the carboranyl- and ethenyl-dipyrroles are potentially valuable precursors for the synthesis of porphyrin isomers and expanded pigments. PMID:21822371

  7. Chemical and Biological Aspects of Marine Sponges from the Family Mycalidae.

    PubMed

    Habener, Leesa J; Hooper, John N A; Carroll, Anthony R

    2016-06-01

    Sponges are a useful source of bioactive natural products. Members of the family Mycalidae, in particular, have provided a variety of chemical structures including alkaloids, polyketides, terpene endoperoxides, peptides, and lipids. This review highlights the compounds isolated from Mycalid sponges and their associated biological activities. A diverse group of 190 compounds have been reported from over 40 specimens contained in 49 references. Over half of the studies have reported on the biological activities for the compounds isolated. The polyketides, in particular the macrolides, displayed potent cytotoxic activities (< 1 µM), and the alkaloids, in particular the 2,5-disubstituted pyrrole derivatives, were associated with moderate cytotoxic activities (1-20 µM). The pyrrole alkaloids and the cyclic peroxides appear to be phylogenetically restricted to sponges and thus might prove useful when applied to sponge taxonomy. The observed diversity of chemical structures suggests this family makes a good target for targeted biodiscovery projects. PMID:27002400

  8. Thermal Degradation Studies on Polyaniline-Polypyrrole Copolymers Prepared by Microemulsion Methods

    NASA Astrophysics Data System (ADS)

    Prasannan, A.; Somanathan, N.; Hong, Po-Da

    2010-05-01

    Solvent- and water-based microemulsions of aniline and pyrrole copolymers were synthesized, and the thermal degradation properties of the copolymers were studied. The morphology of the copolymers prepared using solvent-based microemulsions containing 80 % aniline in the feed showed highly oriented, crystalline, ordered long nano-fibers which were even more structured than that of pure aniline prepared by the same method. The influence of the degree of crystallinity calculated from X-ray diffraction and morphology had an overlap with thermal degradation and activation energies of different transitions. Copolymers prepared with water-based microemulsions were thermally less stable than the ones prepared using solvent-based microemulsions. The concentration of pyrrole and aniline mutually influenced the thermal properties of the copolymers.

  9. A facile method to synthesize polypyrrole nanoparticles in the presence of natural organic phosphate

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Mo, Haodao; Zang, Limin; Qiu, Jianhui; Sakai, Eiichi; Wu, Xueli

    2014-09-01

    The conductive polymers with unique nanostructures have attracted intense interest due to their potential application. Here the well-defined polypyrrole nanoparticles were facile fabricated via the facile chemical oxidative polymerization of pyrrole with high feeding ratio of phytic acid. Phytic acid is a renewable resource and a natural carbohydrate compound with a vast number of phosphate groups from plant which was used as the template and dopant for the nanostructured conductive polymer for the first time. The samples exhibit the well-defined nanoparticles observed by scanning electron microscope (SEM) and atomic force microscope (AFM). The PPy nanoparticles were achieved and outstanding electrical conductivity as high as 5263 S m-1 was obtained with the feeding mass ratio of phytic acid: pyrrole=3:7. Furthermore, the polypyrrole nanoparticles were characterized with Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and electrical conductivity techniques.

  10. Effects of UV radiation on the preparation of polypyrrole in the presence of hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Zhang, Shihu; Lv, Guowei; Wang, Guolong; Zhu, Kaiming; Yu, Demei; Shao, Jinyou

    2015-10-01

    Conductive polypyrrole was synthesized with hydrogen peroxide (H2O2) as the oxidant. To promote the polymerization of pyrrole, UV radiation was employed. The effects of UV radiation on the preparation of polypyrrole were investigated. The polymerization of pyrrole was conducted with the H2O2 concentration in the range of 0.12-0.96 M and the H2SO4 concentration in the range of 6.8×10-4-0.19 M. The structure characterization indicated that the product polypyrrole was overoxidized partly depending on the concentrations of H2SO4 and H2O2. The increase in H2O2 concentration led to a slight increase in the oxidation and overoxidation of polypyrrole, simultaneously. However, the increase in H2SO4 concentration effectively suppressed the overoxidation of polypyrrole. The morphology, conductivity and thermal stability of the products were also characterized.

  11. Synthesis of 1,4-enamino ketones by [3,3]-rearrangements of dialkenylhydroxylamines.

    PubMed

    Pecak, Wiktoria H; Son, Jongwoo; Burnstine, Amy J; Anderson, Laura L

    2014-07-01

    The synthesis of 1,4-enamino ketones has been achieved through the [3,3]-rearrangement of dialkenylhydroxylamines generated from the addition of N-alkenylnitrones to electron-deficient allenes. The mild conditions required for this reaction, and the simultaneous installation of a fluorenyl imine N-protecting group as a consequence of the rearrangement, avoid spontaneous cyclization of the 1,4-enamino ketones to form the corresponding pyrroles and allow for the isolation and controlled divergent functionalization of these reactive intermediates. The optimization, scope, and tolerance of the new method are discussed with demonstrations of the utility of the products for the synthesis of pyrroles, 1,4-diones, and furans. PMID:24961680

  12. The microwave spectrum of neurotransmitter serotonin.

    PubMed

    Cabezas, Carlos; Varela, Marcelino; Peña, Isabel; López, Juan C; Alonso, José L

    2012-10-21

    A laser ablation device in combination with a molecular beam Fourier-transform microwave spectrometer has allowed the observation of the rotational spectrum of serotonin for the first time. Three conformers of the neurotransmitter have been detected and characterized in the 4-10 GHz frequency range. The complicated hyperfine structure arising from the presence of two (14)N nuclei has been fully resolved for all conformers and used for their identification. Nuclear quadrupole coupling constants of the nitrogen atom of the side chain have been used to determine the orientation of the amino group probing the existence of N-Hπ interactions involving the amino group and the pyrrole unit in the Gauche-Phenyl conformer (GPh) or the phenyl unit in the Gauche-Pyrrole (GPy) ones. PMID:22965174

  13. Design, synthesis, and biological evaluation of 2-benzylpyrroles and 2-benzoylpyrroles based on structures of insecticidal chlorfenapyr and natural pyrrolomycins.

    PubMed

    Liu, Yu-Xiu; Zhang, Peng-Xiang; Li, Yong-Qiang; Song, Hai-Bin; Wang, Qing-Min

    2014-08-01

    Based on structures of insecticidal chlorfenapyr and antibiotic natural pyrrolomycins, a series of new 2-benzylpyrroles and 2-benzoylpyrroles (with or without ethoxymethyl group on the nitrogen of pyrrole) were designed and synthesized. These compounds or their parent compounds possess weak acidity and high lipophilicity, the two characteristic properties for uncouplers of oxidative phosphorylation; therefore, they are expected to have insecticidal and acaricidal activity. The bioassay result verified that both 2-benzylpyrroles 17 and 2-benzoylpyrroles 19 had varied degrees of insecticidal activity against oriental armyworm depending on the substituents on the benzene ring, but they did not give any acaricidal activity. Conversely, most N-alkylated compounds 18 and 20 exhibited both insecticidal activity and acaricidal activity, of which compound 18i [4-bromo-2-(2,4-dichlorobenzyl)-1-(ethoxymethyl) -5-(trifluoromethyl) -1H-pyrrole-3-carbonitrile] has IC50 as low as 10-20 mg L(-1) on both activities. PMID:24664285

  14. Stable powders made from photosensitive polycrystalline complexes of heterocyclic monomers and their polymers

    NASA Technical Reports Server (NTRS)

    Hodko, Dalibor (Inventor); Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

    1999-01-01

    The present invention relates to a low electronic conductivity polymer composition having well dispersed metal granules, a stable powder made from photosensitive polycrystalline complexes of pyrrole, or its substituted derivatives and silver cations for making the polymer composition, and methods of forming the stable powder and polymer composition, respectively. A polycrystalline complex of silver and a monomer, such as pyrrole, its substituted derivatives or combinations thereof, is precipitated in the form of a stable photosensitive powder upon addition of the monomer to a solvent solution, such as toluene containing an electron acceptor. The photosensitive powder can be stored in the dark until needed. The powder may be dissolved in a solvent, cast onto a substrate and photopolymerized.

  15. Synthesis of pyrrolo[1,2-a]quinolines and ullazines by visible light mediated one- and twofold annulation of N-arylpyrroles with arylalkynes.

    PubMed

    Das, Amrita; Ghosh, Indrajit; König, Burkhard

    2016-07-01

    1-(2-Bromophenyl)-1H-pyrrole and 1-(2,6-dibromophenyl)-1H-pyrrole react in the presence of catalytic amounts of rhodamine 6G () and N,N-diisopropylethylamine (DIPEA) under blue light irradiation with aromatic alkynes and subsequently cyclize intramolecularly to form pyrrolo[1,2-a]quinoline and ullazines. The reactions proceed at room temperature, avoid transition metal catalysts, and provide the target compounds in one pot in moderate to good yields. Mechanistic investigations suggest that the photo excited is reduced by DIPEA to form the corresponding radical anion , which is again excited by 455 nm light. The excited radical anion of donates an electron to the aryl bromide giving an aryl radical that is trapped by aromatic alkynes. The intermediate vinyl radical cyclizes intramolecularly and yields the product after rearomatization. PMID:27333456

  16. Spectroscopic analysis (FT-IR, FT-Raman and NMR) and molecular docking study of ethyl 2-(4-oxo-3-phenethyl-3,4-dihydroquinazolin-2-ylthio)-acetate

    NASA Astrophysics Data System (ADS)

    El-Azab, Adel S.; Jalaja, K.; Abdel-Aziz, Alaa A.-M.; Al-Obaid, Abdulrahman M.; Sheena Mary, Y.; Yohannan Panicker, C.; Van Alsenoy, C.

    2016-09-01

    The vibrational wavenumbers, molecular structure, MEP, NLO, NBO and HOMO, LUMO analysis of Ethyl 2-(4-oxo-3-phenethyl-3,4-dihydroquinazolin-2-ylthio)-acetate (EPDA) were reported. The change in electron density in the antibonding orbitals and stabilization energies have been calculated by NBO analysis to give clear evidence of stabilization in the hyperconjugation of hydrogen bonded interaction. The difference in HOMO and LUMO energy support the charge transfer interaction within the molecule. NMR studies and Fukui functions are also reported. From molecular electrostatic potential plot it is evident that the negative charge covers the carbonyl groups, phenyl rings and the positive region is over the CH2 groups with the acetate group. Molecular docking studies shows that the title compound forms a stable complex with pyrrole inhibitor and gives a binding affinity value of -8.3 kcal/mol and the results suggest that the compound might exhibit inhibitory activity against pyrrole inhibitor.

  17. N-aryl pyrrolo-tetrathiafulvalene based ligands: synthesis and metal coordination.

    PubMed

    Balandier, Jean-Yves; Chas, Marcos; Dron, Paul I; Goeb, Sébastien; Canevet, David; Belyasmine, Ahmed; Allain, Magali; Sallé, Marc

    2010-03-01

    A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, reminiscent of the corresponding MPTTF derivatives, are provided. When the aryl group is a binding pyridyl unit, the MPTTF derivative 10a can coordinate M(II) salts (M = Pt, Pd). The first examples of metal-directed orthogonal MPTTF-based dimers 11-14, obtained through coordination of 10a to cis-blocked square planar Pt or Pd complexes are described. Studies on the parameters influencing the dimer construction are presented, as well as first recognition properties of the resulting electron-rich clip for C(60). PMID:20143799

  18. β-Alkyloxazolochlorins: Revisiting the Ozonation of Octaalkylporphyrins, and Beyond.

    PubMed

    Sharma, Meenakshi; Meehan, Eileen; Mercado, Brandon Q; Brückner, Christian

    2016-08-01

    The reaction of β-octaalkylporphyrins (octaethylporphyrin and etioporphyrin I) with ozone generated the corresponding heptaalkyloxazolochlorinhemiacetals in which a pyrrolic subunit of the porphyrins was replaced by an oxazoline moiety. Thus, a pyrrolic β-carbon with its alkyl substituent was excised and replaced by an oxygen atom, and the neighboring β-carbon was hydroxylated. This work clarifies the nature of the products first described by Fischer and Deželić, in 1933, and verifies the work by Shulg'a and coworkers, from 1977. Furthermore, the chemistry of the oxazolochlorin hemiacetals was studied: They could be dehydroxylated or converted to alkyl acetals and gem-dialkyl derivatives, all possessing chlorin-type optical spectra. Their oxidative conversions generated a unique tetrahydrofuran-linked oxazolochlorin dimer and a hexaethylporpholactone. The work expands on the knowledge of converting porphyrins to porphyrinoids of potential utility containing nonpyrrolic building heterocycles. PMID:27400266

  19. Effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage.

    PubMed

    Lu, F S H; Bruheim, I; Haugsgjerd, B O; Jacobsen, C

    2014-08-15

    The main objective of this study was to investigate the effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage. Krill oil was incubated at two different temperatures (20 and 40 °C) for 28 or 42 days. The oxidative stability of krill oil was assessed by peroxide value and anisidine value, measurement of lipid derived volatiles, lipid classes and antioxidants. The non-enzymatic browning reactions were assessed through the measurement of pyrroles, free amino acids content and Strecker-derived volatiles. The increase of incubation temperature firstly increased the lipid oxidation in krill oil and subsequently the non-enzymatic browning reactions. The occurrence of these reactions was most likely due to the reaction between α-dicarbonyl or carbonyl compounds with amino acids or ammonia. In addition to tocopherol and astaxanthin esters, the formation of pyrroles might help to protect the krill oil against lipid oxidation. PMID:24679797

  20. Control of work function of graphene by plasma assisted nitrogen doping

    SciTech Connect

    Akada, Keishi; Terasawa, Tomo-o; Imamura, Gaku; Obata, Seiji; Saiki, Koichiro

    2014-03-31

    Nitrogen doping is expected to provide several intriguing properties to graphene. Nitrogen plasma treatment to defect-free and defective highly oriented pyrolytic graphite (HOPG) samples causes doping of nitrogen atom into the graphene layer. Nitrogen atoms are initially doped at a graphitic site (inside the graphene) for the defect-free HOPG, while doping to a pyridinic or a pyrrolic site (edge of the graphene) is dominant for the defective HOPG. The work function of graphene correlates strongly with the site and amount of doped nitrogen. Nitrogen atoms doped at a graphitic site lower the work function, while nitrogen atoms at a pyridinic or a pyrrolic site increase the work function. Control of plasma treatment time and the amount of initial defect could change the work function of graphite from 4.3 eV to 5.4 eV, which would open a way to tailor the nature of graphene for various industrial applications.

  1. Effect of some nitrogen compounds thermal stability of jet A

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1982-01-01

    The effect of known concentrations of some nitrogen containing compounds on the thermal stability of a conventional fuel, namely, Jet A was investigated. The concentration range from 0.01 to 0.1 wt% nitrogen was examined. Solutions were made containing, individually, pyrrole, indole, quinoline, pyridine, and 4 ethylpyridine at 0.01, 0.03, 0.06, and 0.1 wt% nitrogen concentrations in Jet A. The measurements were all made by using a standard ASTM test for evaluating fuel thermal oxidation behavior, namely, ASTM D3241, 'thermal oxidation stability of turbine fuels (JFTOT procedure).' Measurements were made at two temperature settings, and 'breakpoint temperatures' were determined. The results show that the pyrrole and indole solutions have breakpoint temperatures substantially lower than those of the Jet A used.

  2. A semiempirical study of heterocycle oligomers and polymers in different dielectric media

    SciTech Connect

    Juerimaee, T.; Strandberg, M.; Karelson, M.

    1995-06-15

    Four common five-membered heterocycles-pyrrole, phosphole, thiophene, and furan- and their oligomers with the chain length of 2, 4, 6, and 10 units have been studied quantum chemically using the semiempirical PM3 parameterization. The oligomers of pyrrole and phosphole with the homolytically dissociated N-H bond and P-H bond, respectively, and oligomers of thiophene and furan with one electron removed per monomer unit (4n + 2 {pi}-electron bipolaron systems) have also been studied. The electronic properties of the respective polymers were extrapolated from the oligomer data. Bulk polymer effects on the electronic structure were modeled using the self-consistent reaction field theory in the multicavity approximation (MCa SCRF). 48 refs., 3 figs., 6 tabs.

  3. Facile one-step solvothermal synthesis of iron oxide/polypyrrole nanocomposites and their magnetic properties.

    PubMed

    Wang, Hong; Lai, Xiaoyong

    2013-02-01

    Iron oxide/polypyrrole (PPy) nanocomposites (NCs) were prepared by a facile one-step solvothermal process using FeCl3 x 6H2O and pyrrole as starting materials. The resultant products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and superconducting quantum interference device magnetometer (SQUID). TEM image suggested the mesoporosity of the iron oxide/polypyrrole nanocomposites and pyrrole is found to play an important role in controlling the final morphology and porosity of the products. Magnetic hysteresis measurement reveals that nanocomposite shows a superparamagnetic behavior, and possesses a larger saturation magnetization strength (M(s)) of about 15.06 emu/g at room temperature, which allows its application in adsorption or separation as magnetically recyclable materials. PMID:23646672

  4. A glucose oxidase sensor based on screen-printed carbon electrodes modified by polypyrrole.

    PubMed

    Xu, Hui; Li, Guang; Wu, Jieying; Wang, You; Liu, Jun

    2005-01-01

    A disposable amperometric biosensor for detecting blood glucose has been developed. The sensor is based on a screen-printed electrode prepared by electrochemical polymerization of pyrrole with glucose oxidase (GOD) and LiClO4 dopants. In citric acid buffer (pH5.0), GOD with negative charges is immobilized within electropositive polypyrrole matrices onto a carbon electrode surface. Afterward, the electron transfer mediator, potassium ferricyanide is immobilized by adsorption. Experimentally the compositions of pyrrole, LiClO4 and potassium ferricyanide are optimized. Amperometry is used for the determination of glucose concentration. Four microliters of glucose solution is needed for one test, and the response time of the sensor is 70s. The amperometric response of the enzyme electrode is linear in the range of 1-30 mM. PMID:17282595

  5. A Palladium(II)-Catalyzed C-H Activation Cascade Sequence for Polyheterocycle Formation.

    PubMed

    Cooper, Stephen P; Booker-Milburn, Kevin I

    2015-05-26

    Polyheterocycles are found in many natural products and are useful moieties in functional materials and drug design. As part of a program towards the synthesis of Stemona alkaloids, a novel palladium(II)-catalyzed C-H activation strategy for the construction of such systems has been developed. Starting from simple 1,3-dienyl-substituted heterocycles, a large range of polycyclic systems containing pyrrole, indole, furan and thiophene moieties can be synthesized in a single step. PMID:25872492

  6. Discovery of 4-acetyl-3-(4-fluorophenyl)-1-(p-tolyl)-5-methylpyrrole as a dual inhibitor of human P-glycoprotein and Staphylococcus aureus Nor A efflux pump.

    PubMed

    Bharate, Jaideep B; Singh, Samsher; Wani, Abubakar; Sharma, Sadhana; Joshi, Prashant; Khan, Inshad A; Kumar, Ajay; Vishwakarma, Ram A; Bharate, Sandip B

    2015-05-21

    Polysubstituted pyrrole natural products, lamellarins, are known to overcome multi-drug resistance in cancer via the inhibition of p-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) efflux pumps. Herein, a series of simplified polysubstituted pyrroles, prepared via a one-pot domino protocol, were screened for P-gp inhibition in P-gp overexpressing human adenocarcinoma LS-180 cells using a rhodamine 123 efflux assay. Several compounds showed the significant inhibition of P-gp at 50 μM, as indicated by increase in the intracellular accumulation of Rh123 in LS-180 cells. Furthermore, pyrrole 5i decreased the efflux of digoxin, a FDA approved P-gp substrate in MDCK-MDR1 cells with an IC50 of 11.2 μM. In in vivo studies, following the oral administration of a P-gp substrate drug, rifampicin, along with compound , the Cmax and AUC0-∞ of rifampicin was enhanced by 31% and 46%, respectively. All the compounds were then screened for their ability to potentiate ciprofloxacin activity via the inhibition of Staphylococcus aureus Nor A efflux pump. Pyrrole showed the significant inhibition of S. aureus Nor A efflux pump with 8- and 4-fold reductions in the MIC of ciprofloxacin at 50 and 6.25 μM, respectively. The molecular docking studies of compound with the human P-gp and S. aureus Nor A efflux pump identified its plausible binding site and key interactions. Thus, the results presented herein strongly indicate the potential of this scaffold for its use as multi-drug resistance reversal agent or bioavailability enhancer. PMID:25865846

  7. A novel diketopyrrolopyrrole (DPP)-based [2]rotaxane for highly selective optical sensing of fluoride.

    PubMed

    Raju, Mandapati V Ramakrishnam; Lin, Hong-Cheu

    2013-03-15

    A novel [2]rotaxane based on an orthogonal H-bonded motif and 3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) with controlled topicity was successfully constructed, displaying excellent stimulated responses toward anion and solvent polarity. The preorganized host selectively recognized F(-) with high optical sensitivity and reversibility via enhanced positive cooperativity and noncovalent interaction by evidence of a shorter fluorescence lifetime. PMID:23461354

  8. Rhodium(III)-Catalyzed Mild Alkylation of (Hetero)Arenes with Cyclopropanols via C-H Activation and Ring Opening.

    PubMed

    Zhou, Xukai; Yu, Songjie; Qi, Zisong; Kong, Lingheng; Li, Xingwei

    2016-06-01

    The rhodium(III)-catalyzed regioselective alkylation of (hetero)arenes using cyclopropanols as a reactive and efficient coupling partner under oxidative conditions has been developed. This coupling occurred at room temperature via C-H activation of arenes and C-C cleavage of cyclopropanols. Various types of (hetero)arenes (indolines, carbazole, tetrahydrocarbazole, pyrrole, thiophene, etc.) were all successfully reacted under the present conditions. This protocol provides the facile and efficient construction of C7-alkylated indoline scaffolds. PMID:27166521

  9. Catalytic Chemo- and Regioselective Coupling of 1,3-Dicarbonyls with N-Heterocyclic Nucleophiles.

    PubMed

    Kenny, Miles; Kitson, Daniel J; Franckevičius, Vilius

    2016-06-17

    The development of a decarboxylative palladium-catalyzed coupling of 1,3-dicarbonyl compounds with indole, pyrrole, imidazole, and pyrazole nucleophiles via an allylic linker under neutral conditions is disclosed. This process enables the installation of an all-carbon quaternary center and new C-C and C-N bonds in a single operation. Despite the weakly acidic nature of N-heterocycles, the reactions proceed with good efficiency and complete regio- and chemoselectivity. PMID:27211875

  10. Self-assembled ultralight three-dimensional polypyrrole aerogel for effective electromagnetic absorption

    NASA Astrophysics Data System (ADS)

    Xie, Aming; Wu, Fan; Sun, Mengxiao; Dai, Xiaoqing; Xu, Zhuanghu; Qiu, Yanyu; Wang, Yuan; Wang, Mingyang

    2015-06-01

    A facile self-assembled polymerization method has been used to form pyrrole to an ultralight three-dimensional (3D) polypyrrole (PPy) aerogel. It exhibits an effective electromagnetic absorption (EA) bandwidth (deeper than -10 dB), which was characterized as 6.2 GHz when the filler loading is only 7 wt. % in paraffin based composite. This 3D-PPy aerogel can be considered as a light weight, low adjunction, thin thickness, and high performance EA material.

  11. Facile one-pot synthesis of porphyrin based porous polymer networks (PPNs) as biomimetic catalysts

    SciTech Connect

    Zou, LF; Feng, DW; Liu, TF; Chen, YP; Fordham, S; Yuan, S; Tian, J; Zhou, HC

    2015-01-01

    Stable porphyrin based porous polymer networks, PPN-23 and PPN-24, have been synthesized through a facile one-pot approach by the aromatic substitution reactions of pyrrole and aldehydes. PPN-24(Fe) shows high catalytic efficiency as a biomimetic catalyst in the oxidation reaction of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) in the presence of H2O2.

  12. A new reactivity mode for the diazo group: diastereoselective 1,3-aminoalkylation reaction of β-amino-α-diazoesters to give triazolines.

    PubMed

    Kuznetsov, Alexey; Gulevich, Anton V; Wink, Donald J; Gevorgyan, Vladimir

    2014-08-18

    A novel mode of reactivity for the diazo group, the 1,3-addition of a nucleophile and an electrophile to the diazo group, has been realized in the intramolecular aminoalkylation of β-amino-α-diazoesters to form tetrasubstituted 1,2,3-triazolines. The reaction exhibited a broad scope, good functional group tolerance, and excellent diastereoselectivity. In addition, a new Au-catalyzed intramolecular transannulation reaction of the obtained propargyl triazolines to give pyrroles has been discovered. PMID:24986811

  13. A New Reactivity Mode of Diazo-Group: Diastereoselective 1,3-Aminoalkylation Reaction of β-Amino-α-Diazoesters Towards Triazolines**

    PubMed Central

    Kuznetsov, Alexey; Gulevich, Anton V.; Wink, Donald J.

    2014-01-01

    A novel reactivity mode of a diazo-group, the 1,3-addition of a nucleophile and an electrophile to the diazo-group, has been realized in the intramolecular aminoalkylation of β-amino-α-diazoesters to form tetrasubstituted 1,2,3-triazolines. The reaction proved to have a broad scope, good functional group tolerance, and excellent diastereoselectivity. In addition, a new Au-catalyzed intramolecular transannulation reaction of the obtained propargyl triazolines into pyrroles has been discovered. PMID:24986811

  14. Dielectric and electric modulus study of PPy/TiO2/CNT/SLS composite with temperature

    NASA Astrophysics Data System (ADS)

    Tiwari, D. C.; Atri, Priyanka; Sharma, Rishi

    2013-02-01

    Here we report the preparation and electrical characterization of nanocomposite of PPy/TiO2/CNT/SLS synthesized by in situ oxidative polymerization of pyrrole in the presence of TiO2 nanofibers, CNT and surfactant sodium lauryl sulfate. The surface morphology and elemental analysis is studied by SEM and EDAX. Dielectric and modulas studies were carried out in frequency range of 1 KHz to 2 MHz which provides quantitative description of grain and grain boundary effect in nanocomposite material.

  15. The total synthesis of calcium atorvastatin.

    PubMed

    Dias, Luiz C; Vieira, Adriano S; Barreiro, Eliezer J

    2016-02-21

    A practical and convergent asymmetric route to calcium atorvastatin (1) is reported. The synthesis of calcium atorvastatin (1) was performed using the remote 1,5-anti asymmetric induction in the boron-mediated aldol reaction of β-alkoxy methylketone (4) with pyrrolic aldehyde (3) as a key step. Calcium atorvastatin was obtained from aldehyde (3) after 6 steps, with a 41% overall yield. PMID:26795833

  16. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.; Sprague, B.N.

    1989-09-05

    This patent describes a process for the reduction of the concentration of nitrogen oxides in the effluent from the combustion of a carbonaceous fuel. The process comprises introducing a heterocyclic hydrocarbon selected from the group consisting of piperazine, piperidine, pyrazine, pyrazole, imidazole, oxazolidone, pyrrole and pyrrolidine into the effluent having an effluent temperature of greater than about 1200{sup 0}F. under conditions effective to reduce the concentration of nitrogen oxides in the effluent.

  17. Thermodynamics of the hydrogen bonding of nitrogen-containing cyclic and aromatic compounds with proton donors: The structure-property relationship

    NASA Astrophysics Data System (ADS)

    Rakipov, I. T.; Varfolomeev, M. A.; Kirgizov, A. Yu.; Solomonov, B. N.

    2014-12-01

    Enthalpies of dissolution are measured at infinite dilution of nitrogen-containing cyclic (pyrrolidine, piperidine) and aromatic compounds (aniline, N-methylaniline, N,N-dimethylaniline, N-methylimidazole, pyridine, 2-, 3-, 4-methylpyridine, pyrrole, N-methylpyrrole) in chloroform and dichloromethane, and vice versa ( T = 298.15 K). The enthalpies of hydrogen bonds in the above systems are calculated. Relationships between resulting thermochemical data and the structure of nitrogen-containing cyclic and aromatic compounds are explored.

  18. Identification of a Pheromone Component and a Critical Synergist for the Invasive Beetle Callidiellum rufipenne (Coleoptera: Cerambycidae).

    PubMed

    Zou, Yunfan; Rutledge, Claire E; Nakamuta, Kiyoshi; Maier, Chris T; Hanks, Lawrence M; Richards, Austin B; Lacey, Emerson S; Millar, Jocelyn G

    2016-02-01

    The invasive Asian cerambycid beetle Callidiellum rufipenne (Motschulsky), informally known as the Japanese cedar longhorned beetle, was first detected in North America in North Carolina in 1997. The beetle has since been detected in neighboring states and is expected to further expand its range. However, delineating the current distribution of C. rufipenne has been hindered by the lack of efficient sampling methods. Here, we present the results of research on the chemistry of volatile pheromones of C. rufipenne. Analyses of headspace odors revealed that males produce (R)-3-hydroxyhexan-2-one, with lesser amounts of (S)-3-hydroxyhexan-2-one, and (R)- and (S)-2-hydroxyhexan-3-one. In field bioassays conducted over several years in Connecticut, where populations of the beetle were well established, no reconstructed blend of these compounds was significantly attractive to beetles of either sex. However, during field trials in Japan that targeted another species, we discovered that adult male and female C. rufipenne were attracted to a blend of racemic 3-hydroxyhexan-2-one and a novel natural product, 1-(1H-pyrrol-2-yl)-1,2-propanedione. Attraction to (R)-3-hydroxyhexan-2-one and the pyrrole subsequently was confirmed in field trials in Connecticut. Although it is unclear why the pyrrole acts as a synergist for a species that apparently does not produce it, the serendipitous discovery that adult C. rufipenne are attracted by the blend of ketone and pyrrole provides a badly needed method for monitoring its ongoing range expansion within North America, and for detecting new introductions in other parts of the world. PMID:26510607

  19. 5-Bromo-1H-pyrrolo­[2,3-b]pyridine

    PubMed Central

    Štarha, Pavel; Trávníček, Zdeněk

    2013-01-01

    In the title compound, C7H5BrN2, fused six-membered pyridine and five-membered pyrrole rings form the essentially planar aza­indole skeleton (r.m.s. deviation = 0.017 Å). In the crystal, pairs of N—H⋯N hydrogen bonds connect the mol­ecules into inversion dimers. PMID:23476567

  20. Polymeric materials for neovascularization

    NASA Astrophysics Data System (ADS)

    DeVolder, Ross John

    Revascularization therapies have emerged as a promising strategy to treat various acute and chronic wounds, cardiovascular diseases, and tissue defects. It is common to either administer proangiogenic growth factors, such as vascular endothelial growth factor (VEGF), or transplant cells that endogenously express multiple proangiogenic factors. Additionally, these strategies utilize a wide variety of polymeric systems, including hydrogels and biodegradable plastics, to deliver proangiogenic factors in a sophisticated manner to maintain a sustained proangiogenic environment. Despite some impressive results in rebuilding vascular networks, it is still a challenging task to engineer mature and functional neovessels in target tissues, because of the increasing complexities involved with neovascularization applications. To resolve these challenges, this work aims to design a wide variety of proangiogenic biomaterial systems with tunable properties used for neovascularization therapies. This thesis describes the design of several biomaterial systems used for the delivery of proangiogenic factors in neovascularization therapies, including: an electrospun/electrosprayed biodegradable plastic patch used for directional blood vessel growth (Chapter 2), an alginate-g-pyrrole hydrogel system that biochemically stimulates cellular endogenous proangiogenic factor expression (Chapter 3), an enzyme-catalyzed alginate-g-pyrrole hydrogel system for VEGF delivery (Chapter 4), an enzyme-activated alginate-g-pyrrole hydrogel system with systematically controllable electrical and mechanical properties (Chapter 5), and an alginate-g-pyrrole hydrogel that enables the decoupled control of electrical conductivity and mechanical rigidity and is use to electrically stimulate cellular endogenous proangiogenic factor expression (Chapter 6). Overall, the biomaterial systems developed in this thesis will be broadly useful for improving the quality of a wide array of molecular and cellular based

  1. Direct Functionalization of (Un)protected Tetrahydroisoquinoline and Isochroman under Iron and Copper Catalysis: Two Metals, Two Mechanisms

    PubMed Central

    2011-01-01

    A highly facile, straightforward synthesis of 1-(3-indolyl)-tetrahydroisoquinolines was developed using either simple copper or iron catalysts. N-protected and unprotected tetrahydroisoquinolines (THIQ) could be used as starting materials. Extension of the substrate scope of the pronucleophile from indoles to pyrroles and electron-rich arenes was realized. Additionally, methoxyphenylation is not limited to THIQ but can be carried out on isochroman as well, again employing iron and copper catalysis. PMID:21902275

  2. β-Pyrrolopyrazino Annulated Corroles via a Pictet-Spengler Approach.

    PubMed

    Berionni Berna, Beatrice; Nardis, Sara; Galloni, Pierluca; Savoldelli, Andrea; Stefanelli, Manuela; Fronczek, Frank R; Smith, Kevin M; Paolesse, Roberto

    2016-07-15

    Reaction of 2-amino-3-(pyrrol-1-yl)-5,10,15-tris(4-tert-butylphenyl)corrolato copper(II) with arylaldehydes affords novel π-extended β,β'-pyrrolo(1,2-a)pyrazino-fused corroles via a Pictet-Spengler reaction. Corrole shows an unprecedented reaction pathway, leading to a mixture of phenyl-substituted and nonsubstituted pyrrolopyrazino annulated species as reaction products. PMID:27378478

  3. Desorption-induced recombination-cationization of metal-adsorbate adducts from sulfur precovered Ru(0001)

    NASA Astrophysics Data System (ADS)

    Cocco, R. A.; Tatarchuk, B. J.

    1990-03-01

    Temperature programmed static secondary ion mass spectrometry (TPSS) studies of pyrrole, furan and water on sulfur precovered Ru(0001) reveal significant increases in the coverage corrected adduct yield when these species desorb from the surface in an autocatalytic fashion. This effect has been attributed to an enhancement in the recombination-cationization rate which occurs when sputtered-ruthenium species contact desorbed organics just after leaving the surface. Adsorbates which do not undergo autocatalytic/explosive desorption do not exhibit this effect.

  4. Synthesis and Preliminary Biological Study of Bisindolylmethanes Accessed by an Acid-Catalyzed Hydroarylation of Vinylindoles

    PubMed Central

    Pathak, Tejas P.; Osiak, Jaroslaw G.; Vaden, Rachel M.; Welm, Bryan E.; Sigman, Matthew S.

    2012-01-01

    An acid-catalyzed hydroarylation reaction of vinyl indoles is reported, which tolerates a wide range of heterocycles as the exogenous nucleophile such as indoles, pyrroles, and indolizines. The method rapidly accesses the biologically relevant bisindolylmethane scaffold in good to excellent yields. Evaluation of the biological activity of several synthesized analogues reveals cytotoxic activity against and selectivity for the MCF-7 breast cancer cell line. PMID:22778488

  5. Stabilities and structures in cluster ions of five-membered heterocyclic compounds containing O, N, and S atoms

    SciTech Connect

    Hiraoka, K.; Takimoto, H.; Yamabe, S.

    1987-11-25

    Clustering and hydration reactions of protonated and radical cations of heterocyclic compounds, e.g., furan, tetrahydrofuran, pyrrole, pyrrolidine, thiophene, and tetrahydrothiophene, have been studied using a pulsed electron beam mass spectrometer. The bond energies of proton-held dimer cations for furan, pyrrole, and thiophene are much smaller than those for tetrahydrofuran, pyrrolidine, and tetrahydrothiophene, respectively. This result suggests that not the heteroatoms but the ..cap alpha.. carbon atoms are protonated for furan, pyrrole, and thiophene. The hydrogen-bond site for the protonated furan and thiophene is calculated to be the unprotonated ..cap alpha.. hydrogen (C-H/sub ..cap alpha../ adjacent to the heteroatom) which is the most acidic one. On the other hand, the N-H hydrogen is the best hydrogen-bond site for the protonated pyrrole. It was found that the radical-cations dimers have greater bond energies than the proton-held dimer cations for furan and thiophene. This suggests that the bonds of the former have more covalent nature. Some unique reactions of C/sub 4/H/sub 4/O/sup .+/ and C/sub 4/H/sub 5/O/sup +/ with a furan molecule were observed. With an increase of temperature, the ions with m/z which are the same as those for (C/sub 4/H/sub 4/O)/sub 2//sup .+/ and H/sup +/(C/sub 4/H/sub 4/O)/sub 2/ are found to be formed at the expense of C/sup 4/H/sub 4/O/sup .+/ and C/sub 4/H/sub 5/O/sup +/ ions, respectively. It is suggested that the reactions observed are Diels-Alder type condensation reactions.

  6. The different roles of a cationic gold(i) complex in catalysing hydroarylation of alkynes and alkenes with a heterocycle.

    PubMed

    Mehrabi, Tahmineh; Ariafard, Alireza

    2016-08-01

    The mechanism of twofold hydroarylation of terminal alkynes with pyrrole catalyzed by a cationic gold(i) complex was investigated using DFT. It was found that while both the hydroarylation reactions proceed via a Friedel-Crafts-type mechanism, the first hydroarylation is directly promoted by gold(i) but the second hydroarylation by a proton released through interaction of the alkene product with gold-bound acidic organic species such as acetic acid and terminal alkynes. PMID:27377712

  7. Cytotoxicity of pyrrolizidine alkaloid in human hepatic parenchymal and sinusoidal endothelial cells: Firm evidence for the reactive metabolites mediated pyrrolizidine alkaloid-induced hepatotoxicity.

    PubMed

    Yang, Mengbi; Ruan, Jianqing; Fu, Peter P; Lin, Ge

    2016-01-01

    Pyrrolizidine alkaloids (PAs) widely distribute in plants and can cause hepatic sinusoidal obstruction syndrome (HSOS), which typically presents as a primary sinusoidal endothelial cell damage. It is well-recognized that after ingestion, PAs undergo hepatic cytochromes P450 (CYPs)-mediated metabolic activation to generate dehydropyrrolizidine alkaloids (DHPAs), which are hydrolyzed to dehydroretronecine (DHR). DHPAs and DHR are reactive metabolites having same core pyrrole moiety, and can bind proteins to form pyrrole-protein adducts, which are believed as the primary cause for PA-induced HSOS. However, to date, the direct evidences supporting the toxicity of DHPAs and DHR in the liver, in particular in the sinusoidal endothelial cells, are lacking. Using human hepatic sinusoidal endothelial cells (HSEC) and HepG2 (representing hepatic parenchymal cells), cells that lack CYPs activity, this study determined the direct cytotoxicity of dehydromonocrotaline, a representative DHPA, and DHR, but no cytotoxicity of the intact PA (monocrotaline) in both cell lines, confirming that reactive metabolites mediate PA intoxication. Comparing with HepG2, HSEC had significantly lower basal glutathione (GSH) level, and was significantly more susceptible to the reactive metabolites with severer GSH depletion and pyrrole-protein adducts formation. The toxic potency of two reactive metabolites was also compared. DHPA was more reactive than DHR, leading to severer toxicity. In conclusion, our results unambiguously provided the first direct evidence for the critical role of DHPA and DHR in the reactive metabolites-mediated PA-induced hepatotoxicity, which occurs predominantly in HSEC due to severe GSH depletion and the significant formation of pyrrole-protein adducts in HSEC. PMID:26365561

  8. Electrophilic phosphonium cations catalyze hydroarylation and hydrothiolation of olefins.

    PubMed

    Pérez, Manuel; Mahdi, Tayseer; Hounjet, Lindsay J; Stephan, Douglas W

    2015-06-30

    Electrophilic phosphonium cations (EPCs) are efficient main group catalysts for the hydroarylation of olefins under mild conditions, providing a facile route to substituted aniline, bis-arylamine, phenol, furan, thiophene, pyrrole, and indole derivatives. Similarly, EPCs catalyze the hydrothiolation of aryl olefins with thiophenol affording a series of alkyl aryl thioethers. Experimental data support a mechanism for these reactions that involves initial activation of the olefin. PMID:26083901

  9. Virtual libraries of tetrapyrrole macrocycles. Combinatorics, isomers, product distributions, and data mining.

    PubMed

    Taniguchi, Masahiko; Du, Hai; Lindsey, Jonathan S

    2011-09-26

    A software program (PorphyrinViLiGe) has been developed to enumerate the type and relative amounts of substituted tetrapyrrole macrocycles in a virtual library formed by one of four different classes of reactions. The classes include (1) 4-fold reaction of n disubstituted heterocycles (e.g., pyrroles or diiminoisoindolines) to form β-substituted porphyrins, β-substituted tetraazaporphyrins, or α- or β-substituted phthalocyanines; (2) combination of m aminoketones and n diones to form m × n pyrroles, which upon 4-fold reaction give β-substituted porphyrins; (3) derivatization of an 8-point tetrapyrrole scaffold with n reagents, and (4) 4-fold reaction of n aldehydes and pyrrole to form meso-substituted porphyrins. The program accommodates variable ratios of reactants, reversible or irreversible reaction (reaction classes 1 and 2), and degenerate modes of formation. Pólya's theorem (for enumeration of cyclic entities) has also been implemented and provides validation for reaction classes 3 and 4. The output includes the number and identity of distinct reaction-accessible substituent combinations, the number and identity of isomers thereof, and the theoretical mass spectrum. Provisions for data mining enable assessment of the number of products having a chosen pattern of substituents. Examples include derivatization of an octa-substituted phthalocyanine with eight reagents to afford a library of 2,099,728 members (yet only 6435 distinct substituent combinations) and reversible reaction of six distinct disubstituted pyrroles to afford 2649 members (yet only 126 distinct substituent combinations). In general, libraries of substituted tetrapyrrole macrocycles occupy a synthetically accessible region of chemical space that is rich in isomers (>99% or 95% for the two examples, respectively). PMID:21866949

  10. Conjugated Microporous Networks on the Basis of 2,3,5,6-Tetraarylated Diketopyrrolo[3,4-c]pyrrolea

    PubMed Central

    Zhang, Kai; Tieke, Bernd; Vilela, Filipe; Skabara, Peter J

    2011-01-01

    π-Conjugated microporous networks have been prepared from the tetraarylated diketopyrrolo[3,4-c]pyrrole unit as a tetrafunctional building block. The reactions are carried out using microwave-assisted Yamamoto or Sonogashira cross-coupling. Red insoluble powders are obtained, showing intense fluorescence. The polymer networks exhibit a high gas storage capability, with BET surface areas up to about 500 m2 · g−1. PMID:21500301

  11. Pyrrolizidine Alkaloid-Protein Adducts: Potential Non-invasive Biomarkers of Pyrrolizidine Alkaloid-Induced Liver Toxicity and Exposure.

    PubMed

    Xia, Qingsu; Zhao, Yuewei; Lin, Ge; Beland, Frederick A; Cai, Lining; Fu, Peter P

    2016-08-15

    Pyrrolizidine alkaloids (PAs) are phytochemicals present in hundreds of plant species from different families widely distributed in many geographical regions around the world. PA-containing plants are probably the most common type of poisonous plants affecting livestock, wildlife, and humans. There have been many large-scale human poisonings caused by the consumption of food contaminated with toxic PAs. PAs require metabolic activation to generate pyrrolic metabolites to exert their toxicity. In this study, we developed a novel method to quantify pyrrole-protein adducts present in the blood. This method involves the use of AgNO3 in acidic ethanol to cleave the thiol linkage of pyrrole-protein (DHP-protein) adducts, and the resulting 7,9-di-C2H5O-DHP is quantified by HPLC-ES-MS/MS multiple reaction monitoring analysis in the presence of a known quantity of isotopically labeled 7,9-di-C2D5O-DHP internal standard. Using this method, we determined that diester-type PAs administered to rats produced higher levels of DHP-protein adducts than other types of PAs. The results suggest that DHP-protein adducts can potentially serve as minimally invasive biomarkers of PA exposure. PMID:27388689

  12. Frits coated with nano-structured conducting copolymer for solid-phase extraction of polycyclic aromatic hydrocarbons in water samples and liquid chromatographic analysis.

    PubMed

    Rahimi, Mina; Noroozian, Ebrahim

    2014-06-01

    A novel nano-structured conducting copolymer of pyrrole and o-toluidine was electrosynthesized on steel frit as a new sorbent. The applicability of the frit was assessed for the solid-phase extraction (SPE) of Polycyclic aromatic hydrocarbons (PAHs) by coupling with HPLC-UV. The combination of pyrrole and o-toluidine in a copolymer form presents desirable opportunities to produce materials for new applications. The scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and FTIR spectrum for the coated frit were studied. Improved lifetime and satisfactory extraction efficiency were obtained by doping with dodecylbenzenesulfonate (DBS) and oxalate groups into the framework of copolymer. The effects of potential, time and solution concentration (pyrrole, o-toluidine, DBS and oxalic acid) were evaluated in the coating step. The effects of various parameters on the efficiency of the solid-phase extraction process, such as the sample loading rate, elution solvent type, salt effect, volume and flow rate of sample and elution solvent, were investigated. Under optimum conditions, LODs were 0.01-0.08 ng mL(-1). The method showed linearity in the range of 0.1-300 ng mL(-1) with coefficients of determination >0.98. The intra-day (n=7) RSDs obtained at an 8 ng mL(-1) concentration level were <11.4% under optimized conditions respectively. The recoveries (8 and 40 ng mL(-1)) ranged from 64% to 119%. PMID:24725886

  13. Novel nanomaterials based on 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin entrapped in silica matrices

    SciTech Connect

    Fagadar-Cosma, Eugenia; Enache, Corina; Vlascici, Dana; Fagadar-Cosma, Gheorghe; Vasile, Mihaela; Bazylak, Grzegorz

    2009-12-15

    The present study is dealing with the obtaining of transparent hybrid silica materials encapsulating 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin designated for advanced optoelectronic devices. The porphyrin was synthesized by three methods: an Adler-type reaction between pyrrole and 3,4-dimethoxybenzaldehyde in propionic acid medium; by Lindsey condensation of pyrrole with 3,4-dimethoxybenzaldehyde in the presence of BF{sub 3}.OEt{sub 2} and by a multicomponent reaction by simultaneously using of pyrrole and two different aldehydes: 3,4-dimethoxybenzaldehyde and 3-hydroxybenzaldehyde. The 3,4-dimethoxyphenyl substituted porphyrin was characterized by HPLC, TLC, UV-vis, FT-IR, {sup 1}H NMR and {sup 13}C NMR analysis. Excitation and emission spectra were also discussed in terms of pH conditions. The hybrid materials, consisting in the porphyrin encapsulated in silica matrices, have been prepared successfully via the two steps acid-base catalyzed hydrolysis and condensation of tetraethylorthosilicate using different approaches of the sol-gel process: in situ, by impregnation and by sonication. The synthetic conditions and the compositions were monitored and characterized by using spectroscopic methods such as FT-IR, fluorescence and UV-vis. Atomic force microscopy (AFM) has been applied to observe the columnar or pyramidal nanostructures which are formed by the immobilization of porphyrin on the silica matrices.

  14. Synthesis, FT-IR characterization and crystal structure of aqua-(5,10,15,20-tetra-phenyl-porphyrinato-κ(4) N)manganese(III) tri-fluoro-methane-sulfonate.

    PubMed

    Harhouri, Wafa; Mchiri, Chadlia; Najmudin, Shabir; Bonifácio, Cecilia; Nasri, Habib

    2016-05-01

    In the title salt, [Mn(C44H28N4)(H2O)](CF3SO3) or [Mn(III)(TPP)(H2O)](CF3SO3) (where TPP is the dianion of 5,10,15,20-tetra-phenyl-porphyrin), the Mn(III) cation is chelated by the four pyrrole N atoms of the porphyrinate anion and additionally coordinated by an aqua ligand in an apical site, completing the distorted square-pyramidal coordination environment. The average Mn-N(pyrrole) bond length is 1.998 (9) Å and the Mn-O(aqua) bond length is 2.1057 (15) Å. The central Mn(III) ion is displaced by 0.1575 (5) Å from the N4C20 mean plane of the porphyrinate anion towards the apical aqua ligand. The porphyrinate macrocycle exhibits a moderate ruffling and strong saddle deformations. In the crystal lattice, the [Mn(III)(TPP)(H2O)](+) cation and the tri-fluoro-methane-sulfonate counter-ions are arranged in alternating planes packed along [001]. The components are linked together through O-H⋯O hydrogen bonds and much weaker C-H⋯O and C-H⋯F inter-actions. The crystal packing is further stabilized by weak C-H⋯π inter-actions involving the pyrrole and phenyl rings of the porphyrin moieties. PMID:27308027

  15. A gas chromatography-mass spectrometry method for the determination of delta-aminolevulinic acid in plant leaves.

    PubMed

    Hijaz, Faraj; Killiny, Nabil

    2016-05-20

    Delta-aminolevulinic (δ-ALA) acid is an important intermediate for tetrapyrroles biosynthesis and it has recently received great attention in plant physiology and human toxicology. However, the colorimetric method which is the most common method for determination of δ-ALA is time consuming and is not specific. In this study, a method for determination of δ-ALA in plant tissues was developed based on the trimethylsilyl (TMS) derivative of the pyrrole formed from the reaction of δ-ALA with ethyl acetoacetate via Knorr condensation. The δ-ALA in the HCl extract was reacted with ethyl acetoacetate to form a pyrrole. Then, the pyrrole compound was extracted using ethyl acetate and the solvent was evaporated to dryness. The dried sample was derivatized to its TMS ester and analyzed using GC-MS. The concentration of δ-ALA in citrus leaves incubated with levulinic acid was also determined by the conventional colorimetric method. The linear range was 10-200ppm in the full scan mode and 0.1-20ppm in the selected ion monitoring (SIM). The limit of detection was 6ppm in the full scan and 0.05ppm in SIM mode, representing a four-fold increase in sensitivity compared to the colorimetric method. The GC-MS method developed in this study is simple, accurate, sensitive, and could also be used to measure δ-ALA in other biological samples. PMID:27106399

  16. Synthesis and structural characterization of anion complexes with azacalix[2]dipyrrolylmethane: effect of anion charge on the conformation of the macrocycle.

    PubMed

    Guchhait, Tapas; Mani, Ganesan; Schulzke, Carola

    2016-08-01

    Tetrahomodiazacalix[2]dipyrrolylmethane 1, [-CH2(C4H3N)CR2(C4H3N)CH2N(Me)-]2 an expanded version of the calix[4]pyrrole system, has the tendency to change its ring conformation (1,3-alternate) upon anion binding analogous to calix[4]pyrrole. However, owing to its tertiary amine nitrogen atoms in the ring, it can be protonated and becomes a powerful cationic receptor for anions, besides its inherent hydrogen bonding features. Macrocycle 1 binds with a series of monoanions BF4(-), Cl(-), PhCOO(-) and ClO4(-), and their X-ray structures showed that the ring conformation constitutes the 1,2-alternate form. Upon binding with dianions SO4(2-), CrO4(2-), SiF6(2-) and S2O3(2-), the ring conformation changes to the cone conformation. The intermediate partial cone conformation results for complexes with NO3(-) and Cr2O7(2-) ions. The change in the orientation of the pyrrole NH groups depending on the charge of the anion demonstrates the flexibility of the macrocycle and the dicationic macrocycle stabilizes the anions via both hydrogen bonding and electrostatic interactions. PMID:27356484

  17. Red to Near-Infrared Isoindole BODIPY Fluorophores: Synthesis, Crystal Structures, and Spectroscopic and Electrochemical Properties.

    PubMed

    Yu, Changjiang; Wu, Qinghua; Wang, Jun; Wei, Yun; Hao, Erhong; Jiao, Lijuan

    2016-05-01

    A series of high-performance fluorophores named isoindole boron dipyrromethenes (BODIPYs) containing either symmetrical or unsymmetrical alkyl substitution patterns on pyrrole rings were synthesized by an efficient process and were characterized by X-ray diffraction and spectroscopic and electrochemical analyses. Most of these dyes show strong, sharp absorption and bright fluorescence emission in the red to near-infrared (NIR) region (up to 805 nm in acetonitrile). Pyrrolic alkyl substitutions lead to increases in the HOMO and LUMO energy levels and an overall decrease in the energy band gaps of the dye. Among the 23 isoindole BODIPY dyes synthesized, solvent-dependent fluorescence emission and lifetime decay were only observed for those containing a 3-methyl substituent on the uncoordinated pyrrole ring, whereas little variation in the fluorescence intensity was observed for the rest of the dyes upon changing the polarity of the solvent. These resultant dyes can be further functionalized via the Knoevenagel condensation on the α-methyl substituent of the chromophore to install a variety of functionalities, including a dimethylamine group demonstrated in this work. This dimethylamine-functionalized isoindole BODIPY shows weak fluorescence at 805 nm in acetonitrile and a ratiometric "turn-on" NIR fluorescence response to decreasing pH. PMID:27031115

  18. Doping optimization of polypyrrole with toluenesulfonic acid using Box-Behnken design

    NASA Astrophysics Data System (ADS)

    Syed Draman, Sarifah Fauziah; Daik, Rusli; El-Sheikh, Said M.; Latif, Famiza Abdul

    2013-11-01

    A three-level Box-Behnken design was employed in doping optimization of polypyrrole with toluenesulfonic acid (TSA-doped PPy). The material was synthesized via chemical oxidative polymerization using pyrrole, toluenesulfonic acid (TSA) and ammonium persulfate (APS) as monomer, dopant and oxidant, respectively. The critical factors selected for this study were concentration of dopant, molar ratio between dopant to monomer (pyrrole) and concentration of oxidant. Obtaining adequate doping level of TSA-doped PPy is crucial because it affects the charge carriers for doped PPy and usually be responsible for electronic mobility along polymeric chain. Furthermore, the doping level also affects other properties such as electrical and thermal conductivity. Doping level was calculated using elemental analysis. SEM images shows that the prepared TSA-doped PPy particles are spherical in shape with the diameters of about. The range of nanoparticles size is around 80-100 nm. The statistical analysis based on a Box-Behnken design showed that 0.01 mol of TSA, 1:1 mole ratio TSA to pyrrole and 0.25 M APS were the optimum conditions for sufficient doping level.

  19. Ammonia gas sensors based on chemically reduced graphene oxide sheets self-assembled on Au electrodes

    PubMed Central

    2014-01-01

    We present a useful ammonia gas sensor based on chemically reduced graphene oxide (rGO) sheets by self-assembly technique to create conductive networks between parallel Au electrodes. Negative graphene oxide (GO) sheets with large sizes (>10 μm) can be easily electrostatically attracted onto positive Au electrodes modified with cysteamine hydrochloride in aqueous solution. The assembled GO sheets on Au electrodes can be directly reduced into rGO sheets by hydrazine or pyrrole vapor and consequently provide the sensing devices based on self-assembled rGO sheets. Preliminary results, which have been presented on the detection of ammonia (NH3) gas using this facile and scalable fabrication method for practical devices, suggest that pyrrole-vapor-reduced rGO exhibits much better (more than 2.7 times with the concentration of NH3 at 50 ppm) response to NH3 than that of rGO reduced from hydrazine vapor. Furthermore, this novel gas sensor based on rGO reduced from pyrrole shows excellent responsive repeatability to NH3. Overall, the facile electrostatic self-assembly technique in aqueous solution facilitates device fabrication, the resultant self-assembled rGO-based sensing devices, with miniature, low-cost portable characteristics and outstanding sensing performances, which can ensure potential application in gas sensing fields. PMID:24917701

  20. Doping optimization of polypyrrole with toluenesulfonic acid using Box-Behnken design

    SciTech Connect

    Syed Draman, Sarifah Fauziah; Daik, Rusli; El-Sheikh, Said M.; Latif, Famiza Abdul

    2013-11-27

    A three-level Box-Behnken design was employed in doping optimization of polypyrrole with toluenesulfonic acid (TSA-doped PPy). The material was synthesized via chemical oxidative polymerization using pyrrole, toluenesulfonic acid (TSA) and ammonium persulfate (APS) as monomer, dopant and oxidant, respectively. The critical factors selected for this study were concentration of dopant, molar ratio between dopant to monomer (pyrrole) and concentration of oxidant. Obtaining adequate doping level of TSA-doped PPy is crucial because it affects the charge carriers for doped PPy and usually be responsible for electronic mobility along polymeric chain. Furthermore, the doping level also affects other properties such as electrical and thermal conductivity. Doping level was calculated using elemental analysis. SEM images shows that the prepared TSA-doped PPy particles are spherical in shape with the diameters of about. The range of nanoparticles size is around 80-100 nm. The statistical analysis based on a Box–Behnken design showed that 0.01 mol of TSA, 1:1 mole ratio TSA to pyrrole and 0.25 M APS were the optimum conditions for sufficient doping level.

  1. Impact of primary amine group from aminophospholipids and amino acids on marine phospholipids stability: non-enzymatic browning and lipid oxidation.

    PubMed

    Lu, F S H; Nielsen, N S; Baron, C P; Diehl, B W K; Jacobsen, C

    2013-11-15

    The main objective of this study was to investigate the oxidative stability and non-enzymatic browning reactions of marine PL in the presence or in the absence of primary amine group from aminophospholipids and amino acids. Marine phospholipids liposomal dispersions were prepared from two authentic standards (phosphatidylcholine and phosphatidylethanolamine) and two purified PL from marine sources with and without addition of amino acids (leucine, methionine and lysine). Samples were incubated at 60°C for 0, 2, 4 and 6days. Non-enzymatic browning reactions were investigated through measurement of (i) Strecker derived volatiles, (ii) yellowness index (YI), (iii) hydrophobic and (iv) hydrophilic pyrroles content. The oxidative stability of the samples was assessed through measurement of secondary lipid derived volatile oxidation products. The result showed that the presence of PE and amino acids caused the formation of pyrroles, generated Strecker derived volatiles, decreased the YI development and lowered lipid oxidation. The lower degree of lipid oxidation in liposomal dispersions containing amino acids might be attributed to antioxidative properties of pyrroles or amino acids. PMID:23790862

  2. Wittig derivatization of sesquiterpenoid polygodial leads to cytostatic agents with activity against drug resistant cancer cells and capable of pyrrolylation of primary amines.

    PubMed

    Dasari, Ramesh; De Carvalho, Annelise; Medellin, Derek C; Middleton, Kelsey N; Hague, Frédéric; Volmar, Marie N M; Frolova, Liliya V; Rossato, Mateus F; De La Chapa, Jorge J; Dybdal-Hargreaves, Nicholas F; Pillai, Akshita; Kälin, Roland E; Mathieu, Véronique; Rogelj, Snezna; Gonzales, Cara B; Calixto, João B; Evidente, Antonio; Gautier, Mathieu; Munirathinam, Gnanasekar; Glass, Rainer; Burth, Patricia; Pelly, Stephen C; van Otterlo, Willem A L; Kiss, Robert; Kornienko, Alexander

    2015-10-20

    Many types of cancer, including glioma, melanoma, non-small cell lung cancer (NSCLC), among others, are resistant to proapoptotic stimuli and thus poorly responsive to current therapies based on the induction of apoptosis in cancer cells. The current investigation describes the synthesis and anticancer evaluation of unique C12-Wittig derivatives of polygodial, a sesquiterpenoid dialdehyde isolated from Persicaria hydropiper (L.) Delabre. These compounds were found to undergo an unprecedented pyrrole formation with primary amines in a chemical model system, a reaction that could be relevant in the biological environment and lead to the pyrrolation of lysine residues in the target proteins. The anticancer evaluation of these compounds revealed their promising activity against cancer cells displaying various forms of drug resistance, including resistance to proapoptotic agents. Mechanistic studies indicated that compared to the parent polygodial, which displays fixative general cytotoxic action against human cells, the C12-Wittig derivatives exerted their antiproliferative action mainly through cytostatic effects explaining their activity against apoptosis-resistant cancer cells. The possibility for an intriguing covalent modification of proteins through a novel pyrrole formation reaction, as well as useful activities against drug resistant cancer cells, make the described polygodial-derived chemical scaffold an interesting new chemotype warranting thorough investigation. PMID:26360047

  3. Different Effect of the Additional Electron-Withdrawing Cyano Group in Different Conjugation Bridge: The Adjusted Molecular Energy Levels and Largely Improved Photovoltaic Performance.

    PubMed

    Li, Huiyang; Fang, Manman; Hou, Yingqin; Tang, Runli; Yang, Yizhou; Zhong, Cheng; Li, Qianqian; Li, Zhen

    2016-05-18

    Four organic sensitizers (LI-68-LI-71) bearing various conjugated bridges were designed and synthesized, in which the only difference between LI-68 and LI-69 (or LI-70 and LI-71) was the absence/presence of the CN group as the auxiliary electron acceptor. Interestingly, compared to the reference dye of LI-68, LI-69 bearing the additional CN group exhibited the bad performance with the decreased Jsc and Voc values. However, once one thiophene moiety near the anchor group was replaced by pyrrole with the electron-rich property, the resultant LI-71 exhibited a photoelectric conversion efficiency increase by about 3 folds from 2.75% (LI-69) to 7.95% (LI-71), displaying the synergistic effect of the two moieties (CN and pyrrole). Computational analysis disclosed that pyrrole as the auxiliary electron donor (D') in the conjugated bridge can compensate for the lower negative charge in the electron acceptor, which was caused by the CN group as the electron trap, leading to the more efficient electron injection and better photovoltaic performance. PMID:27101840

  4. Synthesis, FT–IR characterization and crystal structure of aqua­(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)manganese(III) tri­fluoro­methane­sulfonate

    PubMed Central

    Harhouri, Wafa; Mchiri, Chadlia; Najmudin, Shabir; Bonifácio, Cecilia; Nasri, Habib

    2016-01-01

    In the title salt, [Mn(C44H28N4)(H2O)](CF3SO3) or [MnIII(TPP)(H2O)](CF3SO3) (where TPP is the dianion of 5,10,15,20-tetra­phenyl­porphyrin), the MnIII cation is chelated by the four pyrrole N atoms of the porphyrinate anion and additionally coordinated by an aqua ligand in an apical site, completing the distorted square-pyramidal coordination environment. The average Mn—N(pyrrole) bond length is 1.998 (9) Å and the Mn—O(aqua) bond length is 2.1057 (15) Å. The central MnIII ion is displaced by 0.1575 (5) Å from the N4C20 mean plane of the porphyrinate anion towards the apical aqua ligand. The porphyrinate macrocycle exhibits a moderate ruffling and strong saddle deformations. In the crystal lattice, the [MnIII(TPP)(H2O)]+ cation and the tri­fluoro­methane­sulfonate counter-ions are arranged in alternating planes packed along [001]. The components are linked together through O—H⋯O hydrogen bonds and much weaker C—H⋯O and C—H⋯F inter­actions. The crystal packing is further stabilized by weak C—H⋯π inter­actions involving the pyrrole and phenyl rings of the porphyrin moieties. PMID:27308027

  5. Dipyrrolylquinoxaline difluoroborates with intense red solid-state fluorescence.

    PubMed

    Yu, Changjiang; Hao, Erhong; Li, Tingting; Wang, Jun; Sheng, Wanle; Wei, Yun; Mu, Xiaolong; Jiao, Lijuan

    2015-08-21

    A set of organic fluorescent dyes of dipyrrolylquinoxalines (PQs ) and their BF2 complexes (BPQs ) were synthesized from commercial reagents, and were characterized by their X-ray structural analysis, and optical and electrochemical properties. BPQs showed intense broad absorption in the visible region in the solution-state. In comparison with that of PQs , there is an over 110 nm red-shift of the absorption maximum in the BPQs (up to 583 nm). Interestingly, dyes all exhibit red solid-state fluorescence with moderate to high fluorescence quantum yields except for PQ which showed bright yellow solid-state fluorescence. X-ray structures of BPQs showed the planar structure of quinoxaline with one pyrrole unit via the BF2 chelation and the almost perpendicular orientation of the uncoordinated pyrrole to the NBN core plane (the dihedral angle of 70-73°). The extended π-conjugation was in good agreement with the observed red-shift of the spectra. These dyes formed well-ordered intermolecular packing structures via the intermolecular hydrogen bonding between the N atoms of quinoxaline moieties and the NH units of adjacent pyrroles. The lack of π-π stacking in their crystal packing structures may explain the interestingly intense solid-state fluorescence of these dyes. PMID:26152609

  6. Enhanced sensitivity in H photofragment detection by two-color reduced-Doppler ion imaging

    SciTech Connect

    Epshtein, Michael; Portnov, Alexander; Kupfer, Rotem; Rosenwaks, Salman; Bar, Ilana

    2013-11-14

    Two-color reduced-Doppler (TCRD) and one-color velocity map imaging (VMI) were used for probing H atom photofragments resulting from the ∼243.1 nm photodissociation of pyrrole. The velocity components of the H photofragments were probed by employing two counterpropagating beams at close and fixed wavelengths of 243.15 and 243.12 nm in TCRD and a single beam at ∼243.1 nm, scanned across the Doppler profile in VMI. The TCRD imaging enabled probing of the entire velocity distribution in a single pulse, resulting in enhanced ionization efficiency, as well as improved sensitivity and signal-to-noise ratio. These advantages were utilized for studying the pyrrole photodissociation at ∼243.1 and 225 nm, where the latter wavelength provided only a slight increase in the H yield over the self-signal from the probe beams. The TCRD imaging enabled obtaining high quality H{sup +} images, even for the low H photofragment yields formed in the 225 nm photolysis process, and allowed determining the velocity distributions and anisotropy parameters and getting insight into pyrrole photodissociation.

  7. Preparation and characterization of a composite hydrogel with graphene oxide as an acid catalyst.

    PubMed

    Jiang, Ting; Sui, Zhu-Yin; Yang, Quan-Sheng; Zhang, Xuetong; Han, Bao-Hang

    2015-04-28

    In this study, a facile method for synthesizing a novel graphene oxide/pyrrole-formaldehyde (GOP-1) composite hydrogel was developed via in situ polymerization of pyrrole and formaldehyde in the presence of graphene oxide sheets without any additional catalyst. During the polymerization, graphene oxide can act as a two-dimensional template to regulate the aggregation state of polymer and as an acid catalyst to accelerate the reaction rate of pyrrole and formaldehyde. The morphology and microstructure were investigated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, respectively. The chemical properties were analyzed via X-ray photoelectron spectroscopy, infrared spectroscopy, and Raman spectroscopy. The freeze-dried GOP-1 composite hydrogel exhibited a large specific surface area, high nitrogen content, and three-dimensional network structure. Based on the above features, the freeze-dried GOP-1 composite hydrogel used as a gas adsorbent showed a high carbon dioxide uptake capacity at 1.0 bar and 273 K (11.1 wt%), in sharp contrast to that of graphene oxide (7.4 wt%). Furthermore, the as-prepared composite hydrogel may possess attractive potential in the fields of electrode material, tissue engineering, and water treatment. PMID:25760407

  8. Highly ordered thin films of polyheterocycles: A synchrotron radiation study of polypyrrole and polythiophene Langmuir-Blodgett films

    SciTech Connect

    Skotheim, T.A.; Yang, X.Q.; Chen, J.; Hale, P.D.; Inagaki, T.; Samuelson, L.; Tripathy, S.; Hong, K.; Rubner, M.F.; den Boer, M.L.

    1988-01-01

    Langmuir-Blodgett films have been made with 3-n-hexadecylpyrrole and 3-n-octadecylpyrrole monomers and copolymers with unsubstituted pyrrole made by chemical polymerization at the air-water interface on a subphase containing FeCl/sub 3/. Langmuir-Blodgett films consisting of mixtures of stearic acid and alkylsubstituted polythiophenes have also been made as bilayer films. The orientation of single and multilayer films on platinum substrates have been studied by Near Edge X-ray Absorption Fine Structure Spectroscopy which also gives information about charge transfer interactions between the aromatic groups and the metallic substrates. The alkylsubstituted pyrroles form highly ordered two-dimensional structures. FeCl/sub 3/ initiated copolymerization with unsubstituted pyrrole leads to a more disordered system. In the case of polythiophene-stearic acid bilayers, the stearic acid layers are highly ordered. The poly(alkyl thiophene) layers sandwiched between stearic acid layers, on the other hand, exhibit random orientation of the thiophene moieties. 15 refs., 3 figs., 3 tabs.

  9. Activated sludge studies of selected contaminants of PFH wastewater

    SciTech Connect

    Dudley, S.K.; Bustamante, R.B.; Bonner, W.P.

    1991-12-31

    Acetone, propionitrile, pyrrole, and thiocyanate were selected as representative compounds of wastewater expected from pressurized, fluidized-bed hydroretorting (PFH) of Eastern oil shales. The PFH process has been the subject of investigation by the Institute of Gas Technology, under contract with the United States Department of Energy, for the purpose of obtaining higher oil yields from Eastern shales than has been possible using conventional retorting methods. Preliminary batch experiments illustrated that acetone, propionitrile, pyrrole, and thiocyanate are aerobically biodegradable by heterogeneous microbiological cultures. Three continuous flow activated sludge reactors were used to further evaluate the biological treatability of the synthetic waste. The studies revealed that the compounds could be removed at hydraulic residence times of as low as one day. Three one-day experiments demonstrated that biological system`s capability to accept organic shock loadings without a change in effluent quality. A no-recycle reactor illustrated that the flocculent microbiological population had a high resistance to solids washout. Because a supplementary nitrogen source was not included in synthetic waste treated by the no-recycle unit, it was shown that propionitrile, pyrrole, and/or thiocyanate supplied the nitrogen necessary for biological activity.

  10. Activated sludge studies of selected contaminants of PFH wastewater

    SciTech Connect

    Dudley, S.K. ); Bustamante, R.B.; Bonner, W.P. )

    1991-01-01

    Acetone, propionitrile, pyrrole, and thiocyanate were selected as representative compounds of wastewater expected from pressurized, fluidized-bed hydroretorting (PFH) of Eastern oil shales. The PFH process has been the subject of investigation by the Institute of Gas Technology, under contract with the United States Department of Energy, for the purpose of obtaining higher oil yields from Eastern shales than has been possible using conventional retorting methods. Preliminary batch experiments illustrated that acetone, propionitrile, pyrrole, and thiocyanate are aerobically biodegradable by heterogeneous microbiological cultures. Three continuous flow activated sludge reactors were used to further evaluate the biological treatability of the synthetic waste. The studies revealed that the compounds could be removed at hydraulic residence times of as low as one day. Three one-day experiments demonstrated that biological system's capability to accept organic shock loadings without a change in effluent quality. A no-recycle reactor illustrated that the flocculent microbiological population had a high resistance to solids washout. Because a supplementary nitrogen source was not included in synthetic waste treated by the no-recycle unit, it was shown that propionitrile, pyrrole, and/or thiocyanate supplied the nitrogen necessary for biological activity.

  11. Ring-strain release in neutral and dicationic 7,8,17,18-tetra-bromo-5,10,15,20-tetra-phenyl-porphyrin: crystal structures of C44H26Br4N4 and C44H28Br4N4 (2+)·2ClO4 (-)·3CH2Cl2.

    PubMed

    Scheidt, W Robert; Duval, Hugues F; Oliver, Allen G

    2016-06-01

    Two porphyrin complexes were studied to determine the effects of protonation on ring deformation within the porphyrin. The porphyrin 7,8,17,18-tetra-bromo-5,10,15,20-tetra-phenyl-porphyrin, C44H26Br4N4, was selected because the neutral species is readily doubly protonated to yield a dication, which was crystallized here with perchlorate counter-ions as a di-chloro-methane tris-olvate, C44H28Br4N4 (2+)·2ClO4 (-)·3CH2Cl2. The centrosymmetric neutral species is observed to have a mild 'ruffling' of the pyrrole rings and is essentially planar throughout; intra-molecular N-H⋯N hydrogen bonds occur. In contrast, the dication exhibits considerable deformation, with the pyrrole rings oriented well out of the plane of the porphyrin, resulting in a 'saddle' conformation of the ring. The charged species forms N-H⋯O hydrogen bonds to the perchlorate anions, which lie above and below the plane of the porphyrin ring. Distortions to the planarity of the pyrrole rings in both cases are very minor. The characterization of the neutral species represents a low-temperature redetermination of the previous room-temperature analyses [Zou et al. (1995 ▸). Acta Cryst. C51, 760-761; Rayati et al. (2008 ▸). Polyhedron, pp. 2285-2290], which showed disorder and physically unrealistic displacement parameters. PMID:27308051

  12. New insights into aromatic pathways of carbachlorins and carbaporphyrins based on calculations of magnetically induced current densities.

    PubMed

    Benkyi, Isaac; Fliegl, Heike; Valiev, Rashid R; Sundholm, Dage

    2016-04-28

    Magnetically induced current densities have been calculated and analyzed for a number of synthesized carbachlorins and carbaporphyrins using density functional theory and the gauge including magnetically induced current (GIMIC) method. Aromatic properties have been determined by using accurate numerical integration of the current flow yielding reliable current strengths and pathways that are related to the degree of aromaticity and the aromatic character of the studied molecules. All investigated compounds are found to be aromatic. However, the obtained aromatic pathways differ from those previously deduced from spectroscopic data and magnetic shielding calculations. For all studied compounds, the ring current divides into an outer and an inner branch at each pyrrolic subring, showing that all π-electrons of the pyrrolic rings take part in the delocalization pathway. The calculations do not support the common notion that the main share of the current takes the inner route at the pyrrolic rings without an inner hydrogen and follows an 18π aromatic pathway. The aromatic pathways of the investigated carbaporphyrins and carbachlorins are very similar, since the current strength via the Cβ[double bond, length as m-dash]Cβ' bond of the cyclopentadienyl ring of the carbaporphyrins is almost as weak as the current density passing the corresponding saturated Cβ-Cβ' bond of the carbachlorins. PMID:26974190

  13. Advancement in conductive cotton fabrics through in situ polymerization of polypyrrole-nanocellulose composites.

    PubMed

    Hebeish, A; Farag, S; Sharaf, S; Shaheen, Th I

    2016-10-20

    Current research was undertaking with a view to innovate a new approach for development of conductive - coated textile materials through coating cotton fabrics with nanocellulose/polypyrrole composites. The study was designed in order to have a clear understanding of the role of nanocellulose as well as modified composite thereof under investigation. It is anticipated that incorporation of nanocellulose in the pyrrole/cotton fabrics/FeCl3/H2O system would form an integral part of the composites with mechanical, electrical or both properties. Three different nanocellulosic substrates are involved in the oxidation polymerization reaction of polypyrrole (Ppy) in presence of cotton fabrics. Polymerization was subsequently carried out by admixing at various ratios of FeCl3 and pyrrole viz. Ppy1, Ppy2 and pp3. The conductive, mechanical and thermal properties of cotton fabrics coated independently with different nanocellulose/polypyrrole were investigated. FTIR, TGA, XRD, SEM and EDX were also used for further characterization. Results signify that, the conductivity of cotton fabrics increases exponentially with increasing the dose of pyrrole and oxidant irrespective of nanocellulose substrate used. While, the mechanical properties of cotton fabrics are not significantly affected by the oxidant treatment. PMID:27474547

  14. Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts

    SciTech Connect

    Li, Xiaoyuan; Czernuszewicz, R.S.; Su, Y.O.; Spiro, T.G. ); Kincaid, J.R. )

    1990-01-11

    Resonance Raman spectra with variable-wavelength excitation are reported for Ni{sup II} porphine (NiP) and for the pyrrole-d{sub 8}, meso-d{sub 4}, and (pyrrole + meso)-d{sub 12} isotopomers, as well as for Ni{sup II} meso-tetraphenylporphine (NiTPP) and its pyrrole-{sup 15}N{sub 4}, pyrrole-d{sub 8}, {sup 13}C{sub 4}-meso, and phenyl-d{sub 20} isotopomers. All the Raman-active in-plane modes have been identified and are assigned to local coordinates which take into account the phasing of adjacent bond stretches within the pyrrole rings and at the methine bridges. The IR spectra of NiP and its isotopomers are also assigned. For most of the local coordinates good frequency agreement is seen for the different symmetry blocks, showing that longer range phasings have minor effects. These in-plane mode assignments are supported by normal-coordinate calculations with a physically reasonable valence force field, which is nearly the same for NiP and NiTPP. The principal force constants are in good accord with bond length relationships selected on the basis of scaled ab initio calculations. The phenyl substituents of NiTPP lower the frequencies of the asymmetric methine bridge stretching modes {nu}{sub 10}(B{sub 1g}) and {nu}{sub 19}(A{sub 2g}) by {approximately}60 cm{sup {minus}1}; this shift is attributable partly to the loss of coupling with the C{sub m}H bending modes in NiP and partly to an electronic effect of the phenyl group. There are also near-resonant interactions in NiTPP between porphyrin and phenyl modes near 740 and 200 cm{sup {minus}1} resulting in strongly displaced modes. Otherwise the phenyl groups have little influence on the porphyrin skeletal mode frequencies. Several phenyl modes are subject to moderate RR enhancement, probably via intensity borrowing from nearby porphyrin modes.

  15. Singlet excited state dipole moments of dual fluorescent N-phenylpyrroles and 4-(dimethylamino)benzonitrile from solvatochromic and thermochromic spectral shifts.

    PubMed

    Yoshihara, Toshitada; Galievsky, Victor A; Druzhinin, Sergey I; Saha, Satyen; Zachariasse, Klaas A

    2003-03-01

    The excited state dipole moments mue(ICT) and mue(LE) of the dual fluorescent molecules N-phenylpyrrole (PP), N-(4-cyanophenyl)pyrrole (PP4C) and N-(3-cyanophenyl)pyrrole (PP3C) are determined from solvatochromic and thermochromic measurements. It is shown that the best results are obtained when the solvatochromic as well as the thermochromic analysis of the spectral shifts is made relative to 4-(dimethylamino)benzonitrile (DMABN) as the model compound. Direct thermochromic experiments with PP4C, PP3C and DMABN in diethyl ether lead to reasonable results, but unrealistically large dipole moments mue(ICT) are found for PP, PP4C, PP3C and DMABN in acetonitrile, ethyl cyanide and n-propyl cyanide. The mue(ICT) values obtained for the N-phenylpyrroles from the thermochromic analysis in these solvents relative to DMABN (17 D) do not depend on solvent polarity: 13 D for PP, 15 D for PP4C and PP3C. The spectral shifts for the LE emission of the N-phenylpyrroles and aminobenzonitriles are much smaller than those for the ICT fluorescence, resulting in relatively small values for mue(LE). With PP and N-(4-methylphenyl)pyrrole (PP4M) the problem arises that one of the two values calculated by solving the quadratic equation for mue(LE) in the solvatochromic and thermochromic analysis cannot be discarded on photophysical or molecular grounds, as is the case for the other molecules. The experimental data for mue(ICT) of PP and PP4C are compared with theoretical values calculated for coplanar (PICT) and perpendicular (TICT) conformations of the pyrrole and phenyl or cyanophenyl groups. The experimental ICT dipole moment of PP4C has a value in between the theoretical results for mue(PICT) and mue(TICT), whereas the data for PP tend to favour the TICT configuration. It appears that in the LE state of PP and PP4M a negative charge remains on the pyrrole moiety, whereas a charge reversal takes place for the LE state of PP3C and the ICT state of PP, PP4C and PP3C. PMID:12713236

  16. Comparative covalent protein binding of 2,5-hexanedione and 3-acetyl-2,5-hexanedione in the rat.

    PubMed

    DeCaprio, Anthony P; Kinney, Elizabeth A; LoPachin, Richard M

    2009-01-01

    2,5-Hexanedione (HD) is the metabolite implicated in n-hexane neurotoxicity. This gamma-diketone reacts with protein lysine amines to form 2,5-dimethylpyrrole adducts. Pyrrole adduction of neurofilaments (NF) and/or other axonal proteins was proposed as a critical step in the neuropathy. While pyrrole adduction is widely accepted as necessary, subsequent pyrrole oxidation, which may result in protein cross-linking, was alternatively postulated as the critical mechanistic step. Previous studies have indicated that 3-acetyl-2,5-HD (AcHD), an analogue that forms pyrroles that do not oxidize, was not neurotoxic in rats. However, relative levels of pyrrole adduction of NF or other axonal proteins were not reported. In the present study, groups of 6 male Wistar rats were given saline, [1,6-(14)C]-HD (3 mmol/kg/d), or [5-(14)C]-AcHD (0.1 mmol/kg/d), i.p. for 21 d. HD- and AcHD-treated rats lost 10% and gained 14% body weight, respectively, compared to a 22% gain for control rats. At termination, HD- and AcHD-treated rats exhibited mean scores of 3.5 and 1.4, respectively, for hindlimb weakness (0-5 scale). Incorporation of radiolabel from HD was 27.8 +/- 3.9, 13.9 +/- 2.6, and 7.8 +/- 0.6 nmol/mg in plasma protein, purified globin, and axonal cytoskeletal proteins, respectively, compared to 0.6 +/- 0.1, 1.6 +/- 0.5, and 1.0 +/- 0.1 for AcHD. Binding of HD to the NF-L, -M, and -H subunit proteins from treated animals was 4-, 24-, and 13-fold higher, respectively, that that of AcHD, indicating differing stoichiometry and patterns of NF adduction for the two diketones. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of globin and NF proteins did not demonstrate protein cross-linking for either diketone at the dose levels and time period examined. These results indicate that that the lack of neurotoxicity previously reported for AcHD may reflect differences in adduct levels at critical axonal target sites rather than an inability to form cross

  17. Copolymères (carbazolylène-pyrrolylène) : synthèse par oxydation chimique et propriétés

    NASA Astrophysics Data System (ADS)

    Boucard, V.; Adès, D.; Siove, A.

    1998-06-01

    Conditions in which (carbazolylene-pyrrolylene) random copolymers could be synthetized directly by chemical oxidation by FeCl3 were studied. A substantial amount of soluble copolymers is obtained after work-up in the conditions corresponding to carbazole/pyrrole/2 FeCl3 molar proportions. An important fraction of polypyrrole was obtained beside a fraction of species soluble in ethanol (carbazole and dimer) and an other fraction of products soluble in water (pyrrole accompanied by the first terms of the oligomeric series). Soluble copolymers were characterized by means of SEC, NMR and UV-Visible spectroscopies. Cyclic voltammetry analysis disclosed that these copolymers exhibit both the carbazolic and the pyrrolic features. Les conditions dans lesquelles des copolymères statistiques (carbazo lylène-pyrrolylène) pouvaient être synthétisés directement par oxydation chimique par FeCl3 ont été étudiées. Des quantités substantielles de copolymères solubles en milieu organique sont obtenues par extraction lorsque les proportions molaires en réactifs carbazole/pyrrole/2 FeCl3 sont utilisées. Une fraction importante de polypyrrole est obtenue à côté d'une fraction d'espèces solubles dans l'éthanol (carbazole et son dimère) et d'une fraction de produits solubles dans l'eau (pyrrole et les premiers termes oligomères). Les copolymères solubles ont été caractérisés par CES, spectroscopies RMN et UV-Visible. L'analyse voltampérométrique de ces matériaux révèle qu'ils possèdent à la fois les caractéristiques des entités carbazolylènes et celles des entités pyrrolylènes.

  18. Crystal structure of di­aqua­[5,10,15,20-tetra­kis­(4-meth­oxy­phen­yl)porphyrinato-κ4 N]iron(III) di­aqua­(18-crown-6)potassium bis­(tri­fluoro­methane­sulfonate)–18-crown-6 (1/2)

    PubMed Central

    Ben Haj Hassen, Leila; Denden, Zouhour; Rousselin, Yoann; Nasri, Habib

    2015-01-01

    In the title compound, [FeIII(C48H36N4O2)(H2O)2][K(C12H24O6)(H2O)2](SO3CF3)2·2C12H24O6, the FeIII atom is situated on an inversion centre and is octa­hedrally coordin­ated by four pyrrole N atoms of the deprotenated 5,10,15,20-tetra­kis­(4-meth­oxy­phen­yl)porphyrinate ligand and two water mol­ecules. The average equatorial Fe—N(pyrrole) bond length [2.043 (6) Å] is consistent with a high-spin (S = 5/2) iron(III) metalloporphyrin derivative. The K+ cation, which also lies on an inversion centre, is chelated by the six O atoms of one 18-crown-6 mol­ecule and is additionally coordinated by two water mol­ecules in a distorted hexa­gonal–bipyramidal geometry. In the crystal, the cations, anions and one non-coordinating 18-crown-6 mol­ecule are linked by classical O—H⋯O hydrogen bonds and non-conventional C—H⋯O hydrogen bonds, leading to a one-dimensional supra­molecular architecture along [10-1]. The crystal packing is further stabilized by weak C—H⋯π inter­actions involving pyrrole and phenyl rings of the porphyrins, as well as weak C—H⋯F contacts involving the (SO3CF3)− counter-ion and the 18-crown-6 mol­ecules. PMID:26870431

  19. Removal of phytotoxic compounds from torrefied grass fibres by plant-beneficial microorganisms.

    PubMed

    Trifonova, Radoslava; Postma, Joeke; Verstappen, Francel W A; Bouwmeester, Harro J; Ketelaars, Jan J M H; van Elsas, Jan-Dirk

    2008-10-01

    We aimed to select microorganisms colonizing torrefied grass fibres (TGF) and simultaneously reducing the phytotoxicity which appeared after heat treatment of the fibres. Eighty-eight bacterial strains and one fungus, previously isolated from a sequential enrichment experiment on torrefied fibres and extracts, were tested separately for their capacity to decrease phytotoxicity. Eleven of the bacterial strains and the fungus significantly reduced phytotoxicity. These organisms were checked for their ability to grow on agar containing phenol, 2-methoxyphenol, 2,6-dimethoxyphenol, 2-furalaldehyde, pyrrole-2-carboxaldehyde and furan-2-methanol as sole carbon sources. The fungus F/TGF15 and the bacterial strain 66/TGF15 were able to grow on all six compounds. Strains 15/TGE5, 23/TGE5, 43/TGE20, 56/TGF10 and 95/TGF15 grew on two to four compounds, and strain 72/TGF15 only on one compound. Strains 31/TGE5, 34/TGE5, 48/TGE20 and 70/TGF15 did not grow on any of the single toxic compounds. GC analyses of torrefied grass extracts (TGE) determined which compounds were removed by the microorganisms. F/TGF15 was the only isolate depleting phenol, 2-methoxyphenol, 2-dihydrofuranone and pyrrole-2,5-dione-3-ethyl-4-methyl. Strains 15/TGE5, 23/TGE5, 31/TGE5 and 56/TGF10, and the fungus depleted 2-furalaldehyde, 2-furan-carboxaldehyde-5-methyl, pyrrole-2-carboxaldehyde, 5-acetoxymethyl-2-furaldehyde and benzaldehyde-3-hydroxy-4-methoxy. These promising candidates for colonizing and simultaneously reducing the phytotoxicity of TGF were affiliated with Pseudomonas putida, Serratia plymuthica, Pseudomonas corrugata, Methylobacterium radiotolerans and Coniochaeta ligniaria. PMID:18537835

  20. Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium enzyme at near-atomic resolution

    SciTech Connect

    Azim, N.; Deery, E.; Warren, M. J.; Wolfenden, B. A. A.; Erskine, P.; Cooper, J. B. Coker, A.; Wood, S. P.; Akhtar, M.

    2014-03-01

    The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step in the biosynthesis of tetrapyrroles in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. Two near-atomic resolution structures of PBGD from B. megaterium are reported that demonstrate the time-dependent accumulation of partially oxidized forms of the cofactor, including one that possesses a tetrahedral C atom in the terminal pyrrole ring. The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form.