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21.
2-Arylimino-3-aryl-thiazolidine-4-thiones were synthesized from the corresponding thiazolidine-4-ones using Lawesson's reagent (LR) and converted into 5-benzylidine-2-arylimino-3-aryl-thiazolidine-4-thiones by reaction with benzaldehyde, which were then used as heterodienes in the inverse-electron-demand hetero Diels–Alder cycloadditions with norbornene as a dienophile at 25 °C. The reactions with norbornene were found to proceed with 100% exo-selectivity as determined by NMR experiments. The hetero Diels–Alder reactions with axially chiral heterodienes with ΔG#>116 kJ/mol showed kinetic atroposelectivities up to 11:1. However, the products were found to equilibrate, as revealed by the 97.1 kJ/mol barrier to hindered rotation of the most sterically hindered product, to produce 2:1 diastereoselectivities after the 24 h reaction time. 相似文献
22.
Attahiru Sule Alfa Elias Yannopoulos 《The Journal of the Operational Research Society》1993,44(3):271-278
We present a class of bulk server queueing models encountered in material handling and public transportation systems. Customers arrive according to the Poisson process and server visits form a Markov renewal process. Results for the queue length at steady state are obtained and a numerical example using observed data is presented. 相似文献
23.
Ahmet Demirbas Sule Ceylan Neslihan Demirbas 《Journal of heterocyclic chemistry》2007,44(6):1271-1280
The synthesis and structural properties of two kinds of thiosemicarbazide derivatives ( 2a‐c and 3a‐c ) and one kind of semicarbazide derivatives ( 4a, 4b ) have been described. These compounds were synthesized by treating 2‐(4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)acetohydrazides ( 1a‐c ) with benzyl isothiocyanate, 3‐florophenyl isothiocyanate and benzylisocyanate, respectively. The synthesis of 4‐amino‐3‐alkyl‐1‐[(4‐alkyl‐5‐mercapto(or 5‐oxo)‐4H‐1,2,4‐triazol‐3‐yl)methyl]‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones ( 5a‐c, 6a‐c and 7 ) have been performed from the reaction with sodium hydroxide. On the other hand, the acidic treatment of compounds 2b, 3b and 4b has afforded 4‐amino‐3‐(4‐chlorobenzyl)‐1‐[(5‐alkylamino‐1,3,4‐thidazol(or 1,3,4‐oxazol)‐2‐yl)methyl]‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones ( 8, 9 and 10 ). The condensation of thiosemi(or semi)carbazide derivatives ( 2a‐c, 3c and 4b ) with 4‐chlorophenacylbromide have resulted in the formation of 2‐[4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl]‐N′‐(3,4‐dialkyl‐1,3‐thiazol(or oxazol)‐2(3H)‐yliden]acetohydrazides ( 11a‐c, 12, 13 ), while their condensation with chloroacetic acid has produced 2‐[4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl]‐N′‐[3‐(3‐alkyl)]‐4‐oxo‐1,3‐thiazolidin(or oxazolidin)‐2‐yliden}acetohydrazides ( 14, 15 and 16 ). The spectral data and elemental analyses have support the proposed structures. 相似文献
24.
Axially chiral 2-arylimino-3-aryl-thiazolidine-4-ones have been synthesized as racemic mixtures, and each mixture with the exception of 2-(o-chlorophenyl)imino-3-(o-chlorophenyl)-thiazolidine-4-one has been converted to the corresponding 5-benzylidene-2-arylimino-3-aryl-thiazolidine-4-one racemates by reaction with benzaldehyde. The thermally interconvertible enantiomers of each compound have been obtained by enantioselective HPLC separation on columns Chiralpak AD-H and Chiralcel OD-H, and the barriers to racemization have been found to be 98.1-114.1 kJ/mol. The barriers determined were compared to those of structurally related compounds to provide evidence for the stereochemistry of the aryl imino bond. 相似文献
25.
Cem?GokEmail author Dogukan?Alkim?Turkozu Sule?Aytas 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):533-541
Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the
red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous
solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time,
temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning
electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption
characteristics, Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms were applied to the adsorption data.
The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin–Radushkevich
equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics
properties of the biosorption (ΔG°, ΔH° and ΔS°) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous
and more favorable at lower temperature under examined conditions. 相似文献
26.
Jagannath U. K. Goutam R. K. Sharma J. Singh K. Dutta U. S. Sule R. Pradeep S. C. Gadkari 《Journal of synchrotron radiation》2018,25(5):1541-1547
The Hard X‐ray Photo‐Electron Spectroscopy (HAXPES) beamline (PES‐BL14), installed at the 1.5 T bending‐magnet port at the Indian synchrotron (Indus‐2), is now available to users. The beamline can be used for X‐ray photo‐emission electron spectroscopy measurements on solid samples. The PES beamline has an excitation energy range from 3 keV to 15 keV for increased bulk sensitivity. An in‐house‐developed double‐crystal monochromator [Si (111)] and a platinum‐coated X‐ray mirror are used for the beam monochromatization and manipulation, respectively. This beamline is equipped with a high‐energy (up to 15 keV) high‐resolution (meV) hemispherical analyzer with a microchannel plate and CCD detector system with SpecsLab Prodigy and CasaXPS software. Additional user facilities include a thin‐film laboratory for sample preparation and a workstation for on‐site data processing. In this article, the design details of the beamline, other facilities and some recent scientific results are described. 相似文献
27.
Sema Akyil Sule Aytas D.A. Turkozu Mahmoud A.A. Aslani Sabriye Yusan Meral Eral 《Radiation measurements》2009,44(4):390-395
The aim of this study is to determine the radioactivity levels as a baseline for further studies and to obtain the distribution patterns of radioactivity in lake surface water around Izmir/Turkey. In this study, surface water samples were collected from three lakes around Izmir–Turkey. Surface water samples were analyzed for pH, mV conductivity and alkalinity content. The gross alpha/beta and uranium concentrations were investigated in the collected lake water samples. Mean gross alpha and gross beta activity concentrations in the surface water were found to be between (0.03 and 2.62) Bq l−1 for Karagol Lake, (0.75 and 2.35) Bq l−1 for Golcuk Lake, (0.03 and 1.77) Bq l−1 for Cakalbogaz Lake, respectively. Uranium concentration varied between (0.05 and 900) μg l−1 for Karagol Lake, (0.05 and 0.95) μg l−1 for Golcuk Lake and (3.33 and 10) μg l−1 for Cakalbogaz Lake. Radioactivity contour maps were produced and their data were evaluated statistically. 相似文献
28.
Diffuse reflectance spectrum of Co3+-N-Acetylacetone-anthranilic acid complex is reported between 50.000-10.000 cm?1. Two absorption peaks have been observed at 34.310 and 20.000 cm?. They have been assigned to 1T2g ? 1A1g and 1T1g ? 1A1g transitions. 相似文献
29.
We report state-to-state and overall thermal rate constants for the isotope exchange reaction D((2)S)+OH((2)Pi)-->OD((2)Pi)+H((2)S) for 0 K相似文献
30.
A novel distyryl-substituted boradiazaindacene (BODIPY) dye displays interesting properties as a sensitizer in DSSC systems, opening the way to further exploration of structure-efficiency correlation within this class of dyes. 相似文献