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171.
172.
Michel Boisbrun Elka Vassileva Marion Raoul Jean-Yves Laronze Janos Sapi 《Monatshefte für Chemie / Chemical Monthly》2003,134(12):1641-1649
Summary. In view of finding new 5-HT6 receptor ligands various -acetamido substituted tryptamine and N,N-dimethyltryptamine derivatives were synthesized from a common intermediate. A trimolecular condensation between indole, Meldrums acid and N-phthalimidoacetaldehyde followed by careful deprotection and functional group manipulations were proposed for this purpose.Present address: GEVSM, UMR 7565 CNRS-UHP, Faculté de Pharmacie, F-54001 Nancy Cedex, FrancePresent address: University of Global and National Economy, Studentski Grad Christo Botev, BG-1700 Sofia, Bulgaria 相似文献
173.
Using low angle laser light scattering, weight averaged molecular weights, M?w, diffusion coefficients, and hydrodynamic radii, RH, have been determined for completely synthetic surfactant vesicles, prepared by ultrasonic irradiation of dioctadecyldimethylammonium chloride. DODAC, and dihexadecylphosphate. DHP dispersion. Both the M?w and RH values were found to decrease exponentially as a function of sonication time. At the limit, M?w and RH for DODAC vesicles are 12.6 × 106 dalton and 396 Å, and those for DHP vesicles are 23 × 106 dalton and 595 Å. Calculations indicate both vesicles to be prolates. 相似文献
174.
Janos Pless Wilfried Bauer Francis Cardinaux Annemarie Closse Daniel Hauser Ren Huguenin Dietmar Roemer Heinz-Hermann Buescher Ronald Charles Hill 《Helvetica chimica acta》1979,62(2):398-411
The synthesis and biological testing of analogues of Met-enkephalin, a recently discovered opioid peptide from mammalian brain, are described. Testing involved determination of affinity constants for an opiate receptor site and of analgesic potency in the tail-flick test in mouse. The effects on opioid activity of modifying various parts of the enkephalin molecule are discussed. Tyr-D -Ala-Gly-MePheMet (O)-ol 1 The ending -ol added to the symbol of an amino acid designates the aminoalcohol obtained by reduction of the α-carboxyl group of the amino acid. (FK 33-824), which was highly active in these tests, was subsequently selected for clinical testing. The use of two complementary models - in vitro binding studies and in vivo test for analgesia - for the assessment of biological activity in the evaluation of analogues is explained. 相似文献
175.
The thermal rearrangement of 7 -propargyloxy-cycloheptatriene in decane solution at 180°C gave bicyclo[3.3.2]deca-3,7,9-trien-2-one ( 13 ) and the unstable 2,7-dihydro-cyclohepta[ b ]-pyran ( 12 ) (Scheme 2). The structures of these compounds were determined mainly by NMR. spectroscopy. Derivatives of 13 were also identified by comparison with known compounds (Scheme 3). Possible mechanisms for the formation of 13 and 12 are outlined in Schemes 5 and 6 respectively. The thermal rearrangement of 2-propargyloxy-cycloheptatrienone ( 21 ) gave, in high yield, 2-methyl-8H-cyclohepta[b]furan-8-one ( 22 ) (Scheme 7). 相似文献
176.
Lu D Nadas J Zhang G Johnson W Zweier JL Cardounel AJ Villamena FA Wang PG 《Journal of the American Chemical Society》2007,129(17):5503-5514
S-Nitrosothiols (RSNOs) are important exogenous and endogenous sources of nitric oxide (NO) in biological systems. A series of 4-aryl-1,3,2-oxathiazolylium-5-olates derivatives with varying aryl para-substituents (-CF3, -H, -Cl, and -OCH3) were synthesized. These compounds were found to release NO under acidic condition (pH = 5). The decomposition pathway of the aryloxathiazolyliumolates proceeded via an acid-catalyzed ring-opening mechanism after which NO was released and an S-centered radical was generated. Electron paramagnetic resonance (EPR) spin trapping studies were performed to detect NO and the S-centered radical using the spin traps of iron(II) N-methyl-D-glucamine dithiocarbamate [(MGD)2-FeII] and 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Also, EPR spin trapping and UV-vis spectrophotometry were used to analyze the effect of aryl para substitution on the NO-releasing property of aryloxathiazolyliumolates. The results showed that the presence of an electron-withdrawing substituent such as -CF3 enhanced the NO-releasing capability of the aryloxathiazolyliumolates, whereas an electron-donating substituent like methoxy (-OCH3) diminished it. Computational studies using density functional theory (DFT) at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level were used to rationalize the experimental observations. The aryloxathiazolyliumolates diminished susceptibility to reduction by ascorbate or gluthathione, and their capacity to cause vasodilation as compared to other S-nitrosothiols suggests potential application in biological systems. 相似文献
177.
Imasheva ES Balashov SP Wang JM Smolensky E Sheves M Lanyi JK 《Photochemistry and photobiology》2008,84(4):977-984
Xanthorhodopsin is a light-driven proton pump in the extremely halophilic bacterium Salinibacter ruber. Its unique feature is that besides retinal it has a carotenoid, salinixanthin, with a light harvesting function. Tight and specific binding of the carotenoid antenna is controlled by binding of the retinal. Addition of all-trans retinal to xanthorhodopsin bleached with hydroxylamine restores not only the retinal chromophore absorption band, but causes sharpening of the salinixanthin bands reflecting its rigid binding by the protein. In this report we examine the correlation of the changes in the two chromophores during bleaching and reconstitution with native all-trans retinal, artificial retinal analogs and retinol. Bleaching and reconstitution both appear to be multistage processes. The carotenoid absorption changes during bleaching occurred not only upon hydrolysis of the Schiff base but continued while the retinal was leaving its binding site. In the case of reconstitution, the 13-desmethyl analog formed the protonated Schiff base slower than retinal, and provided the opportunity to observe changes in carotenoid binding at various stages. The characteristic sharpening of the carotenoid bands, indicative of its reduced conformational heterogeneity in the binding site, occurs when the retinal occupies the binding site but the covalent bond to Lys-240 via a Schiff base is not yet formed. This is confirmed by the results for retinol reconstitution, where the Schiff base does not form but the carotenoid exhibits its characteristic spectral change from the binding. 相似文献
178.
Janos K. Aranyosi Erika Galgoczi Annamaria Erdei Monika Katko Mariann Fodor Zoltan Ujhelyi Ildiko Bacskay Endre V. Nagy Bernadett Ujhelyi 《Molecules (Basel, Switzerland)》2022,27(9)
Thyroid autoimmunity in Graves’ disease (GD) is accompanied by Graves’ orbitopathy (GO) in 40% of the cases. Orbital fibroblasts (OF) play a key role in the pathogenesis and cigarette smoking is a known deteriorating factor. Alongside conventional cigarettes (CC) new alternatives became available for smokers, including heated tobacco products (HTP) and E-cigarettes (ECIG). We aimed to study the cellular effects of smoke extracts (SE) in orbital fibroblasts. Primary OF cultures from GO and NON-GO orbits were exposed to different concentrations of SE (1%, 50%) and the changes were followed using Real Time Cell Electronic Sensing (RT-CES). Untreated GO and NON-GO cells had different maximum cell index (CI) values of 3.3 and 2.79 respectively (p < 0.0001). CC, HTP and ECIG treated NON-GO fibroblasts exhibited peak CIs of 2.62, 3.32 and 3.41 while treated GO cells’ CIs were higher, 5.38, 6.25 and 6.33, respectively (p < 0.0001). The metabolic activity (MTT) decreased (p < 0.001) and hyaluronan production doubled (p < 0.02) after 50% of CC SE treatment in all cell cultures. GO fibroblasts were more sensitive to low concentration SE then NON-GO fibroblasts (p < 0.0001). The studied SEs exerted different effects. RT-CES is a sensitive technique to detect the effects of very low concentration of SE on fibroblasts. 相似文献
179.
180.
Klaus Hinterding Patrizia Hagenbuch Janos Rtey Herbert Waldmann 《Angewandte Chemie (International ed. in English)》1998,37(9):1236-1239
A modularly built bisubstrate inhibitor , the natural product pepticinnamin E (shown on the right) was sythesized for the first time. In the case of in vitro assays it inhibits the enzyme farnesyltransferase with respect to both the peptide substrate and farnesylpyrophosphate (KI = 30 and 8 μM , respectively). The inhibitory activity is decisively influenced by the central tripeptide unit and the absolute configuration of the non-proteinogenic amino acid incorporated therein. 相似文献