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1.
[reaction: see text] The enediamine tautomer of a variety of substituted amidine free bases reacts with nitric oxide (NO) to produce compounds containing a carbon-bound diazeniumdiolate [R1R2R3C-N(O)=NO-] functional group (previously called "nitrosohydroxylamines"). The new reaction has been shown to be quite general, although the nature of the products does vary. Amidines containing more than one replaceable hydrogen produce polydiazeniumdiolates as intermolecular salts, while those in which only one diazeniumdiolation can occur provide zwitterionic salts. These diazeniumdiolated amidines are shown to be useful NO donor compounds which undergo very slow spontaneous dissociation on dissolution in pH 7.4 phosphate buffer to produce mixtures of NO and nitrous oxide containing mostly NO. The most advantageous manifestation of the new discovery is the preparation of the monodiazeniumdiolated amidine zwitterions. Reaction of the medically relevant alpha-adrenergic agonists tetrahydrozoline and idazoxan produced monodiazeniumdiolated amidine zwitterions from which NO release was observed for up to 28 days and showed little sign of ending. The reaction should be applicable to a variety of pharmaceutical agents, including NO synthase inhibitors, antitumor agents, and antibacterials. 相似文献
2.
Hrabie JA Arnold EV Citro ML George C Keefer LK 《The Journal of organic chemistry》2000,65(18):5745-5751
The reaction of nitric oxide (NO) with enamines has been investigated. Unlike previously reported reactions of NO as a free radical with alkenes, the electrophilic addition of NO to the beta-carbon of enamines results in the formation of compounds containing the diazeniumdiolate functional group (-[N(O)NO](-)). This reaction between NO and enamines has been shown to be quite general and a variety of enamine-derived diazeniumdiolates have been isolated and characterized. While enamines derived from aldehydes and ketones whose structures allow for sequential multiple electrophilic additions tended to undergo overreaction leading to unstable products, it has been shown that this complication may be overcome by suitable choice of reaction solvent. The products obtained may exist as zwitterionic iminium salts or as neutral species depending upon the structure of the parent enamine. The diazeniumdiolate derived from 1-(N-morpholino)cyclohexene is unique among the new compounds in that it spontaneously releases NO upon dissolution in buffered aqueous solution at pH 7.4 and 37 degrees C. While the total quantity of NO released by this material (ca. 7% of the theoretical 2 moles) is apparently limited by a competing reaction in which it hydrolyzes to an alpha-diazeniumdiolated carbonyl compound and the parent amine, this feature may prove to be of great value in the development of multiaction pharmaceuticals based upon this new type of NO-releasing compound. Reports of enzymatic (oxidative) release of NO from previously known carbon-bound diazeniumdiolates also suggest that analogues of these compounds may be useful as pharmaceutical agents. This new method of introducing the relatively rarely studied diazeniumdiolate functional group into organic compounds should lead to further research into its chemical and biological properties. 相似文献
3.
We provide a brief overview of our Hamiltonian approach to the the Kondo-lattice state at both finite Coulomb interaction U and nonzero applied magnetic field. In the mean-field approximation we introduce the spindependent effective masses, as well as calculate the effective Kondo (hybridization) temperature as a function of U. The effective interaction coming from the slave-boson exchange is shown to contain both the local (intraband) pairing and the Kondo (interband) interaction. 相似文献
4.
V. A. Moskalenko P. Entel D. F. Digor L. A. Dohotaru R. Citro 《Theoretical and Mathematical Physics》2008,155(3):914-935
We propose a diagram theory around the atomic limit for the single-impurity Anderson model in which the strongly correlated
impurity electrons hybridize with free (uncorrelated) conduction electrons. Using this diagram approach, we prove a linked-cluster
theorem for the vacuum diagrams and derive Dyson-type equations for localized and conduction electrons and the corresponding
equations for mixed propagators. The system of equations can be closed by summing an infinite series of ladder diagrams containing
irreducible Green’s functions. The result allows discussing resonances associated with quantum transitions at the impurity
site.
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Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 155, No. 3, pp. 474–497, June, 2008. 相似文献
5.
R. Citro A. Minguzzi E. Orignac A. Recati T. Roscilde 《The European physical journal. Special topics》2013,216(1):1-2
Among many notable jubilees brought by the year 2012, the one of a special importance for the community of statistical physicists was the 140th birth anniversary of Marian Smoluchowski (Maryan Ritter von Smolan Smoluchowski, 28.05.1872 - 5.09.1917), who was one of the pioneers of statistical physics and, on a larger scale, one of those who shaped modern physical science as a whole. The present issue of EPJ ST entitled From Brownian motion to self-avoiding walks and Lévy flights aims to reflect the evolution of Smoluchowski’s ideas in the field of statistics of interacting random and self-avoiding walks, stochastic equations for many-particle systems, physics of glass-forming and noise driven systems. Majority of papers in this issue were presented at the international conference in statistical physics that took place in Lviv (Ukraine) on July 3-6, 2012. 相似文献
6.
CM Silva MF Duarte ML Mira MH Florêncio K Versluis AJ Heck 《Rapid communications in mass spectrometry : RCM》1999,13(12):1098-1103
Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
7.
X. Deng R. Citro E. Orignac A. Minguzzi 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(3):435-443
Using exact diagonalisation and Density Matrix Renormalisation group (DMRG) approach we analyse the transition to a localised
state of a weakly interacting quasi-1D Bose gas subjected to a quasiperiodic potential. The analysis is performed by calculating
the superfluid fraction, density profile, momentum distribution and visibility for different periodicities of the second lattice
and in the presence (or not) of a weak repulsive interaction. It is shown that the transition is sharper towards the maximally
incommensurate ratio between the two lattice periodicities, and shifted to higher values of the second lattice strength by
weak repulsive interactions. We also relate our results to recent experiments. 相似文献
8.
Catarina IV Ramos Flávio Figueira Marcelo D Polêto Francisco ML Amado Hugo Verli João PC Tomé M Graça PMS Neves 《Journal of mass spectrometry : JMS》2016,51(5):342-349
Electrospray mass spectrometry/mass spectrometry was used to investigate the gas‐phase properties of protonated expanded porphyrins, in order to correlate those with their structure and conformation. We have selected five expanded meso‐pentafluorophenyl porphyrins, respectively, a pair of oxidized/reduced fused pentaphyrins (22 and 24 π electrons), a pair of oxidized/reduced regular hexaphyrins (26 and 28 π electrons) and a regular doubly N‐fused hexaphyrin (28 π electrons). The gas‐phase behavior of the protonated species of oxidized and reduced expanded porphyrins is different. The oxidized species (aromatic Hückel systems) fragment more extensively, mainly by the loss of two HF molecules. The reduced species (Möbius aromatic or Möbius‐like aromatic systems) fragment less than their oxidized counterparts because of their increased flexibility. The protonated regular doubly fused hexaphyrin (non‐aromatic Hückel system) shows the least fragmentation even at higher collision energies. In general, cyclization through losses of HF molecules decreases from the aromatic Hückel systems to Möbius aromatic or Möbius‐like aromatic systems to non‐aromatic Hückel systems and is related to an increase in conformational distortion. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
R. Citro M. Marinaro 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(3):343-348
Within the single band 2D-Hubbard model treated by means of a strong-coupling approach based on a cumulant expansion and a
nonstandard diagrammatic technique, we discuss the existence of critical charge fluctuations that could give rise to an instability
towards a phase separation (PS). It turns out that such instability exists and evolves into an incommensurate charge density
wave (ICDW) when long-range Coulomb forces are taken into account. We find a stripe phase with a crossover from diagonal to
vertical stripes at increasing doping in the range 0.01 ?δ? 0.2 and increasing Coulomb potential U, similarly to recent NMR experiments on La
2 - x
Sr
x
CuO
4.
Received 20 November 2000 相似文献
10.