Search results for "Oxazole"

Study of thermal spin crossover in [Fe(II)(isoxazole)(6)](BF4)(2) with Mossbauer spectroscopy

2007

Fe-57 Mossbauer spectroscopy of the mononuclear [Fe( II)( isoxazole)(6)]( BF4)(2) compound has been studied to reveal the thermal spin crossover of Fe( II) between low- spin ( S = 0) and high- spin ( S = 2) states. A temperature-dependent spin transition curve has been constructed with the least- square fitted data obtained from the Mossbauer spectra measured at various temperatures in the 240 - 60 K range during the cooling and heating cycle. The compound exhibits a temperature- dependent two- step spin transition phenomenon with T-SCO ( step 1) = 92 and TSCO ( step 2) = 191 K. The compound has three highspin Fe( II) sites at the highest temperature of study; among them, two have slightly …

Reduced presynaptic efficiency of excitatory synaptic transmission impairs LTP in the visual cortex of BDNF-heterozygous mice

2006

The neurotrophin brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival, axonal and dendritic growth and synapse formation. BDNF has also been reported to mediate visual cortex plasticity. Here we studied the cellular mechanisms of BDNF-mediated changes in synaptic plasticity, excitatory synaptic transmission and long-term potentiation (LTP) in the visual cortex of heterozygous BDNF-knockout mice (BDNF(+/-)). Patch-clamp recordings in slices showed an approximately 50% reduction in the frequency of miniature excitatory postsynaptic currents (mEPSCs) compared to wild-type animals, in the absence of changes in mEPSC amplitudes. A presynaptic impairment of excita…

Dendritic Ih selectively blocks temporal summation of unsynchronized distal inputs in CA1 pyramidal neurons.

2004

The active dendritic conductances shape the input-output properties of many principal neurons in different brain regions, and the various ways in which they regulate neuronal excitability need to be investigated to better understand their functional consequences. Using a realistic model of a hippocampal CA1 pyramidal neuron, we show a major role for the hyperpolarization-activated current, I-h, in regulating the spike probability of a neuron when independent synaptic inputs are activated with different degrees of synchronization and at different distances from the soma. The results allowed us to make the experimentally testable prediction that the I-h in these neurons is needed to reduce ne…

Synthesis of Azole-Heterocycles as Potential Antitumor and/or Antiviral Agents

2014

Kelfiprim, a new sulpha-trimethoprim combination, versus cotrimoxazole, in the treatment of urinary tract infections: a multicentre, double-blind tri…

1982

A new combination of trimethoprim with a sulphonamide, named Kelfiprim, differs from cotrimoxazole in that: a) the sulpha drug is sulphamethopyrazine instead of sulphamethoxazole; b) the trimethoprim to sulpha ratio is 5:4 instead of 1:5;c) the presence of a long-acting sulphonamide allows the administration of a daily dose of one capsule, following an initial loading dose of two capsules; d) a reduced amount of trimethoprim is given, as compared to cotrimoxazole, without any decrease of efficacy. Kelfiprim [KP] was compared to contrimoxazole [Co] in a multicentre double blind trial. Sixty four patients suffering from acute and chronic infections of the upper and lower urinary tract entered…

Survivin is regulated by interleukin-4 in colon cancer stem cells

2010

Colorectal cancer has provided an important model to test the stem cell hypothesis of cancer origin, which implies that cancer arises as a result of genetic aberrations in stem cells leading to deregulation of the proliferation/differentiation balance. We and others have demonstrated that, similarly to other solid tumors, colon carcinogenesis and progression are dictated by highly apoptosis-resistant stem-like cells. Our data have suggested that protection from apoptosis is achieved by autocrine production of interleukin-4 (IL-4) through up-regulation of anti-apoptotic mediators. In this study, we extend our analysis to another apoptosis inhibitor widely expressed in tumors, namely survivin…

Cytotoxic and protein kinase inhibiting nakijiquinones and nakijiquinols from the sponge Dactylospongia metachromia.

2014

Chemical investigation of the sponge Dactylospongia metachromia afforded five new sesquiterpene aminoquinones (1-5), two new sesquiterpene benzoxazoles (6 and 7), the known analogue 18-hydroxy-5-epi-hyrtiophenol (8), and a known glycerolipid. The structures of all compounds were unambiguously elucidated by one- and two-dimensional NMR and by MS analyses, as well as by comparison with the literature. Compounds 1-5 showed potent cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values ranging from 1.1 to 3.7 μM. When tested in vitro for their inhibitory potential against 16 different protein kinases, compounds 5, 6, and 8 exhibited the strongest inhibitory activity against AL…

Identification of pyrrolo[3',4':3,4]cyclohepta[1,2-d][1,2]oxazoles as promising new candidates for the treatment of lymphomas

2023

Unsatisfactory outcomes for relapsed/refractory lymphoma patients prompt continuing efforts to develop new therapeutic strategies. Our previous studies on pyrrole-based anti-lymphoma agents led us to synthesize a new series of twenty-six pyrrolo[3′,4':3,4]cyclohepta[1,2-d] [1,2]oxazole derivatives and study their antiproliferative effects against a panel of four non-Hodgkin lymphoma cell lines. Several candidates showed significant anti-proliferative effects, with IC50's reaching the sub-micromolar range in at least one cell line, with compound 3z demonstrating sub-micromolar growth inhibitory effects towards the entire panel. The VL51 cell line was the most sensitive, with an IC50 value of…

Preparation and Structure of Diexo-Oxanorbornane-fused 1,3-Heterocycles

2004

Via the reaction of diexo-oxanorbornanedicarboxylic anhydride with toluene, the diexo-aroylcarboxylic acid (3a) was prepared, which exists partly as the tautomeric lactol (3b). With bifunctional reagents, 3a yields fused heterocycles containing three-six rings. Thus, alkylenediamines result in imidazole- and 1,3-diazepine-fused oxygen- bridged isoindolones (6a,b), alkanolamines form the oxazole- and 1,3-oxazine-fused oxanorbornene derivatives (7a-c), and o-phenylenediamine undergoes cyclization to furnish the condensed benzimidazole (8). The reaction of 3a with diexo- aminonorbornanecarbohydrazide yields a pyrimidopyridazine containing six condensed rings (9). In a similar reaction with die…

Radical Cyclization and 1,5-Hydrogen Transfer in Selected Aromatic Diazonium Salts

2014

2-(Methyl(3-methyl-1-phenyl-1H-pyrazol-5-yl)carbamoyl)thiophene-3-diazonium hydrogen sulfate 20, 2-(methyl(3-methyl-isoxazol-5yl)carbamoyl)-benzenediazonium hydrogen sulfate 21 and 2-(methyl(phenyl)carbamoyl)-benzenediazonium hydrogen sulphate 22 were synthesized and reacted with a CuSO4/NaCl/ascorbic acid combination to give complex mixtures. The structures of the reaction products were elucidated, depending upon the pathways followed. Compound 20 almost exclusively afforded an Ar-5 cyclization product and trace amounts of the product derived from a competing Ar-6 Pschorr closure. In the case of compound 21, the Ar-6 cyclization was not observed, while the Ar-5 cyclization and 1,5-hydrogen…