Search results for "Pyridine"
showing 10 items of 2516 documents
Base Control of Electron-Transfer Reactions of Manganese(III) Porphyrins
2000
Homogeneous electron-transfer kinetics for the reduction of four different manganese(III) porphyrins using different reductants were examined in deaerated acetonitrile, and the resulting data were evaluated in light of the Marcus theory of electron transfer to determine electron-exchange rate constants between manganese(III) and manganese(II) porphyrins. The investigated compounds are represented as (P)MnCl, where P = the dianion of dodecaphenylporphyrin (DPPX; X = H20, Cl12H8, or F20) or tetraphenylporphyrin (TPP). The electron transfer from semiquinone radical anion derivatives to (P)MnIIICl leads to formation of the corresponding MnII complex, [(P)MnIICl]−. The electron-exchange rate con…
A study of the Candida albicans cell wall proteome
2008
Considering the importance of proteins in the structure and function of the cell wall of Candida albicans, we analyzed the cell wall subproteome of this important human pathogen by LC coupled to MS (LC-MS) using different protein extraction procedures. The analyzed samples included material extracted by hydrogen fluoride-pyridine (HF-pyridine), and whole SDS-extracted cell walls. The use of this latter innovative procedure gave similar data as compared to the analysis of HF-pyridine extracted proteins. A total of 21 cell wall proteins predicted to contain a signal peptide were identified, together with a high content of potentially glycosylated Ser/Thr residues, and the presence of a GPI mo…
4-Aminopyridine (4AP) Enhances Acetylcholine Output from the Rat Cerebral Cortex in vivo
1982
Publisher Summary This chapter discusses a study to analyze the effect of 4-aminopyridine (4AP) administration on cortical acetylcholine (ACh) output. The study was done on adult male Wistar rats under urethane or pentobarbital anesthesia. A small Perspex cylinder filled with eserinized Ringer solution was applied on the exposed cerebral cortex. The solution in the collecting cylinder was removed every 10 min and its ACh content was determined by bioassay on the dorsal muscle of the leech. In urethane anaesthetized rats, the control ACh output was 0.98 ± 0.16 ng/min/cm2 and the administration of 4AP (3 mg/kg i.p.) was followed by a rapid increase in ACh output lasting at least 40 min. The i…
Bis(pyridylvinyl)diaminobenzenes: synthesis, acidochromism and solvatochromism of the fluorescence
2005
Abstract C2-symmetrical 1,4-distyrylbenzenes with 4-dimethylaminobenzene or pyridine as terminal rings, and propyloxy or dipropylamino groups in the central 2,5-positions were prepared. Solvatochromism of the absorption is small, but more pronounced in the fluorescence spectra. Some compounds exhibit huge Stokes shifts. Acid strongly alters the fluorescence: red shifts and decreasing quantum yields is the general result, but depending on the position and character of the basic sites, a strong recovery of fluorescence efficiency combined with large hypsochromic shifts may result in highly acidic solutions.
ChemInform Abstract: Solvent-Dependent Facile Synthesis of Diaryl Selenides and Biphenols Employing Selenium Dioxide.
2016
The reaction of phenols (I) with selenium dioxide in pyridine leads to diaryl selenides (IIa-d), whilst the reaction in acetic acid gives rise to biphenols (III).
Binding of water and solvent molecules in a 25-membered-ring host compound
1993
The macrocyclic 15- and 25-membered-ring pyridine oligomers 1 and 2 containing three and five methoxy substituents in the 4-position of the pyridine rings were prepared by Muller-Roscheisen cyclization and then isolated by chromatography. They are attractive as synthetic endobasic receptor molecules. X-ray structure analysis exhibits the inclusion of hydrogen-bonded solvent molecules (water and trichloromethane) inside the pentameric macrocycle 2.
1H NMR-spektroskopische Untersuchungen zur Strukturaufklärung von Oligo(hydroxy-5-nitro-1,3-phenylen)methylen Verbindungen
1976
Die 1H NMR-Spektren von 51 Oligo(hydroxy-5-nitro-1,3-phenylen)methylen Verbindungen (17 Zwei-, 18 Drei-, 14 Vier- und 2 Funfkernverbindungen) wurden in Pyridin als Losungsmittel aufgenommen. Bei Verbindungen mit ortho-Nitrophenolbausteinen zeigten die Signale fur die Protonen der Methyl- bzw. Methylengruppen in allen Fallen charakteristische chemische Verschiebungen δ, so das eine eindeutige Unterscheidung zwischen Methylgruppen in para- (δ=2,09−2,15 p.p.m.) und ortho-Stellung (δ=2,22−2,28 p.p.m.) zur phenolischen Hydroxyl-Gruppe, sowie zwischen para-para- (δ=3,77−3,97 p.p.m.), ortho-para- (δ=4,02−4,12 p.p.m.) und ortho-ortho-Methylenbrucken (δ=4,21−4,32 p.p.m.) moglich war. Bei Verbindunge…
Sunitinib in patients with advanced hepatocellular carcinoma after progression under sorafenib treatment.
2010
<i>Objective:</i> To evaluate the safety and efficacy of sunitinib in patients with advanced hepatocellular carcinoma (HCC) after progression under sorafenib treatment. <i>Methods:</i> Sunitinib was administered at 37.5 mg daily (4-weeks-on/2-weeks-off schedule) after progression under sorafenib treatment. Adverse events (AEs) were assessed using NCI-CTCAE v3.0, and tumor response was evaluated according to RECIST. Data were analyzed retrospectively. <i>Results:</i> Eleven patients with metastatic disease were treated. Seven patients (64%) presented with no liver cirrhosis, including 3 patients with a history of liver transplantation. The first radiologic…
Molecular mechanisms of sorafenib action in liver cancer cells.
2012
Sorafenib, a multikinase inhibitor, recently received FDA approval for the treatment of advanced hepatocellular carcinoma (HCC). However, as the clinical application of sorafenib evolves, there is increasing interest in defining the mechanisms underlying its anti-tumor activity. Considering that this specific inhibitor could target unexpected molecules depending on the biologic context, a precise understanding of its mechanism of action could be critical to maximize its treatment efficacy, while minimizing adverse effects. Two human HCC cell lines (HepG2 and Huh7), carrying different biological and genetic characteristics, were used in this study to examine the intracellular events leading …
A systems biology perspective on cholangiocellular carcinoma development: focus on MAPK-signaling and the extracellular environment.
2008
Background/Aims Multiple genes have been implicated in cholangiocellular carcinoma (CCC) development. However, the overall neoplastic risk is likely associated with a much lower number of critical physiological pathways. Methods To investigate this hypothesis, we extracted all published genetic associations for the development of CCC from PubMed (genetic association studies, but also studies associating genes and CCC in general, i.e. functional studies in cell lines, genetic studies in humans, knockout mice etc.) and integrated CCC microarray data. Results We demonstrated the MAPK pathway was consistently enriched in CCC. Comparing our data to genetic associations in HCC often successfully …