69 research outputs found
Synthesis of New Bitopic Tetra(pyrazolyl)-Ligands with Neopentane and O-Xylene Backbones
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
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
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
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
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
We consider preheating in the theory , where the classical oscillating inflaton field decays
into -particles and -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 . We construct the
stability/instability chart in this theory for arbitrary . We give
simple analytic solutions describing the resonance in the limiting cases
and , and in the theory with
, and with . From the point of view of parametric
resonance for , the theories with and with
have the same structure, respectively, as the theory , and
the theory of an N-component scalar field
in the limit . We show that in some of the conformally
invariant theories such as the simplest model , the
resonance can be terminated by the backreaction of produced particles long
before become of the order . 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
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
We study inflationary models in which the effective potential of the inflaton
field does not have a minimum, but rather gradually decreases at large .
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
of the inflaton field with another scalar field
. 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 is extremely small, .Comment: 10 pages, revte
11<i>H</i>-Indeno[1,2-<i>b</i>]quinoxalin-11-one 2-(4-ethylbenzylidene)hydrazone
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 ischemiaâreperfusion injury
11H-Indeno[1,2-b]quinoxalin-11-one 2-(4-ethylbenzylidene)hydrazone
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
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