69 research outputs found

    Synthesis of New Bitopic Tetra(pyrazolyl)-Ligands with Neopentane and O-Xylene Backbones

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    Several new bitopic pyrazole-containing ligands were prepared from the corresponding pyrazoles and tetrahalogen or tetratosyloxy derivatives of o-xylene and neopentane in a superbasic medium (KOH-DMSO)

    Facile Synthesis of Pyrazole- and Benzotriazole-Containing Selenoethers

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    Azole-containing selenoethers, 1,5-bis(3,5-dimethylpyrazol-1-yl)-3-selena pentane and 1,3-bis(1,2,3-benzotriazol-1-yl)-2-selena propane were prepared by the reaction of corresponding tosylate or chloride with sodium selenide generated in situ from elemental selenium and sodium formaldehydesulfoxylate (rongalite)

    Synthesis and pharmacological evaluation of indole derivatives as deaza analogues of potent human neutrophil elastase inhibitors

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    A number of N-benzoylindoles were designed and synthesized as deaza analogues of our previously reported potent and selective HNE inhibitors with an indazole scaffold. The new compounds containing substituents and functions that were most active in the previous series were active in the micromolar range (the most potent had IC(50)=3.8 ”M) or inactive. These results demonstrated the importance of N-2 in the indazole nucleus. Docking studies performed on several compounds containing the same substituents but with an indole or an indazole scaffold, respectively, highlight interesting aspects concerning the molecule orientation and H-bonding interactions, which could help to explain the lower activity of this new series

    Valley Method Versus Instanton-Induced Effective Lagrangean Up to (E/Esphaleron)8/3(E/E_{\rm sphaleron})^{8/3}

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    We compare the two most popular approaches to the problem of instanton-antiinstanton interaction at high energies - the valley method and the effective-Lagrangian approach - and use them to calculate the next-to-next-to-leading term in the expansion of ``holy grail'' function determining the cross section with baryon number violation in the Standard Model.Comment: 46 pages, LaTeX, UFTP 323/1992, and PSU/TH/11

    Preheating, Supersymmetry Breaking and Baryogenesis

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    Fluctuations of scalar fields produced at the stage of preheating after inflation are so large that they can break supersymmetry much stronger than inflation itself. These fluctuations may lead to symmetry restoration along flat directions of the effective potential even in the theories where the usual high temperature corrections are exponentially suppressed. Our results show that nonthermal phase transitions after preheating may play a crucial role in the generation of the primordial baryon asymmetry by the Affleck-Dine mechanism. In particular, the baryon asymmetry may be generated at the very early stage of the evolution of the Universe, at the preheating era, and not when the Hubble parameter becomes of order the gravitino mass.Comment: 4 pages, no figure

    Structure of Resonance in Preheating after Inflation

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    We consider preheating in the theory 1/4λϕ4+1/2g2ϕ2χ21/4 \lambda \phi^4 + 1/2 g^2\phi^2\chi^2 , where the classical oscillating inflaton field ϕ\phi decays into χ\chi-particles and ϕ\phi-particles. The parametric resonance which leads to particle production in this conformally invariant theory is described by the Lame equation. It significantly differs from the resonance in the theory with a quadratic potential. The structure of the resonance depends in a rather nontrivial way on the parameter g2/λg^2/\lambda. We construct the stability/instability chart in this theory for arbitrary g2/λg^2/\lambda. We give simple analytic solutions describing the resonance in the limiting cases g2/λâ‰Ș1g^2/\lambda\ll 1 and g2/λ≫1g^2/\lambda \gg 1, and in the theory with g2=3λg^2=3\lambda, and with g2=λg^2 =\lambda. From the point of view of parametric resonance for χ\chi, the theories with g2=3λg^2=3\lambda and with g2=λg^2 =\lambda have the same structure, respectively, as the theory 1/4λϕ41/4 \lambda \phi^4, and the theory λ/(4N)(ϕi2)2\lambda /(4 N) (\phi^2_i)^2 of an N-component scalar field ϕi\phi_i in the limit N→∞N \to \infty. We show that in some of the conformally invariant theories such as the simplest model 1/4λϕ41/4 \lambda\phi^4, the resonance can be terminated by the backreaction of produced particles long before or or become of the order ϕ2\phi^2. We analyze the changes in the theory of reheating in this model which appear if the inflaton field has a small mass.Comment: 19 pages, revtex, 12 figure

    GUT Baryogenesis after Preheating

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    At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number. We propose that the baryon asymmetry is generated by the decay of supermassive Grand Unified Theory (GUT) bosons produced non-thermally in a preheating phase after inflation. We show that baryogenesis is possible for an inflaton masses of order 10^{13} GeV and a GUT Higgs boson mass of order 10^{14} GeV, thus solving many drawbacks facing GUT baryogenesis in the old reheating scenario.Comment: 4 pages, version to be published in Phys. Rev. Let

    Inflation and Preheating in NO models

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    We study inflationary models in which the effective potential of the inflaton field does not have a minimum, but rather gradually decreases at large ϕ\phi. In such models the inflaton field does not oscillate after inflation, and its effective mass becomes vanishingly small, so the standard theory of reheating based on the decay of the oscillating inflaton field does not apply. For a long time the only mechanism of reheating in such non-oscillatory (NO) models was based on gravitational particle production in an expanding universe. This mechanism is very inefficient. We will show that it may lead to cosmological problems associated with large isocurvature fluctuations and overproduction of dangerous relics such as gravitinos and moduli fields. We also note that the setting of initial conditions for the stage of reheating in these models should be reconsidered. All of these problems can be resolved in the context of the recently proposed scenario of instant preheating if there exists an interaction g2ϕ2χ2{g^2} \phi^2\chi^2 of the inflaton field ϕ\phi with another scalar field χ\chi. We show that the mechanism of instant preheating in NO models is much more efficient than the usual mechanism of gravitational particle production even if the coupling constant g2g^2 is extremely small, 10−14â‰Șg2â‰Ș110^{-14} \ll g^2 \ll 1.Comment: 10 pages, revte

    11<i>H</i>-Indeno[1,2-<i>b</i>]quinoxalin-11-one 2-(4-ethylbenzylidene)hydrazone

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    11H-Indeno[1,2-b]quinoxaline derivatives present an important type of nitrogen-containing heterocyclic compound that are useful intermediate products in organic synthesis and have potential pharmaceutical applications. A new 11H-indeno[1,2-b]quinoxalin-11-one-2-(4-ethylbenzylidene)hydrazone (compound 3) was synthesized. Compound 3 is the first example of an azine derivative based on the 11H-indeno[1,2-b]quinoxaline system. The Z,E-isomerism of compound 3 was investigated by DFT calculations. Bioavailability was evaluated in silico using ADME predictions. According to the ADME results, compound 3 is potentially highly bioavailable and has potential to be used for the treatment of neuroinflammation and ischemia–reperfusion injury

    11H-Indeno[1,2-b]quinoxalin-11-one 2-(4-ethylbenzylidene)hydrazone

    No full text
    11H-Indeno[1,2-b]quinoxaline derivatives present an important type of nitrogen-containing heterocyclic compound that are useful intermediate products in organic synthesis and have potential pharmaceutical applications. A new 11H-indeno[1,2-b]quinoxalin-11-one-2-(4-ethylbenzylidene)hydrazone (compound 3) was synthesized. Compound 3 is the first example of an azine derivative based on the 11H-indeno[1,2-b]quinoxaline system. The Z,E-isomerism of compound 3 was investigated by DFT calculations. Bioavailability was evaluated in silico using ADME predictions. According to the ADME results, compound 3 is potentially highly bioavailable and has potential to be used for the treatment of neuroinflammation and ischemia&ndash;reperfusion injury
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