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Delest B Nshimyumukiza P Fasbender O Tinant B Marchand-Brynaert J Darro F Robiette R 《The Journal of organic chemistry》2008,73(17):6816-6823
A divergent and regioselective synthesis of 1,2,4- and 1,2,5-trisubstituted imidazoles from a readily available (two steps) common intermediate has been developed. This methodology is based on the regiocontrolled N-alkylation of 1-(N,N-dimethylsulfamoyl)-5-iodo-2-phenylthio-1H-imidazole (10). When this intermediate is engaged in reaction with methyl triflate, selective formation of the corresponding 1,2,5-trisubsituted 1H-imidazole is observed. NMR studies have revealed that this regioselectivity can be accounted for by in situ rapid isomerization of 10 into its 1,2,4-isomer (13) followed by regiospecific N-alkylation of the latter. Conversely, when key intermediate 10 is slowly added to Meerwein's salt, isomerization can be constrained and regiospecific N-alkylation of 10 leads to 1,2,4-trisubstituted 1H-imidazole with a high selectivity. The general character of this methodology has been illustrated by showing that iodine in position 4 or 5 could be easily substituted by an aryl group by Suzuki coupling, whereas the phenylthio group at position 2 could, after oxidation into sulfone, be displaced by nucleophilic substitution. 相似文献
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Masota Nelson E. Tibalinda Prosper Shedafa Raphael Sempombe Joseph Kaale Eliangiringa A. 《平面色谱法杂志一现代薄层色谱法》2016,29(6):469-473
JPC – Journal of Planar Chromatography – Modern TLC - A new high-performance thin-layer chromatographic (HPTLC)—densitometric method which can be employed in the routine analysis... 相似文献
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Harrison B Prosper 《Pramana》2000,54(4):611-622
I review the solar neutrino problem and what it has taught us about the Sun and fundamental physics. 相似文献
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Inhibitory efficacy has been determined by the method of the weight losses of steel in acid with native lignin, hydrolysis lignin, ammoniated native lignin, chlorinated hydrolysis lignin, and ammoniated hydrolysis lignin, and without these additives. It has been established that the efficacy of lignin and its modifications as inhibitors of acid corrosion increases with a rise in the number of carboxy groups in the macromolecule, and therefore the ammoniated hydrolysis lignin is the most effective.Central Scientific-Research and Planning Technological Institute for the Mechanization and Electrification of Animal Husbandry of the Southern Zone of the USSR. Zaporozh'e Astrakhan Technical Institute of the Fisheries Industry and Economy, Astrakhan'. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 378–380, May–June, 1983. 相似文献
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Fluorescent labelling of thiols with monobromobimane followed by RP-18 reversed-phase HPLC with aqueous acetic acid/acetone mixtures and fluorescence detection (λ(ex) = 380 nm;λ(em) = 470 nm) allows their selective and sensitive identification in various preparations. 相似文献
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Prosper Nshimyumukiza Emilie Van Den Berge Tatjana Mijatovic Jacqueline Marchand-Brynaert 《Tetrahedron》2010,66(25):4515-2004
A new family of compounds made of a 5-aryl-1H-imidazole motif included in a macrocycle has been designed and synthesized. The synthesis of the imidazole core makes use of our previously developed method for the regioselective preparation of 1,2,5-trisubstituted imidazoles while the construction of the macrocycle is based on a three steps sequence: SNAr, Suzuki coupling, and RCM reaction. Biological evaluation of synthesized imidazole-containing macrocycles revealed that they display actual binding activity toward A3 adenosine (h) receptor, dopamine D1 (h) receptor, chloride channel (GABA-gated), and choline transporter (h) CHT1. 相似文献
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Prosper?KanyongEmail authorView authors OrcID profile Francis?D.?Krampa Yaw?Aniweh Gordon?A.?Awandare 《Mikrochimica acta》2017,184(10):3663-3671
This review (with 35 references) summarizes the various strategies used in biosensors for galactose, and their analytical performance. A brief comparison of the enzyme immobilization methods employed and the analytical performance characteristics of a range of galactose biosensors are first summarized in tabular form and then described in detail. Selected examples have been included to demonstrate the various applications of these biosensors to real samples. Following an introduction into the field that covers the significance of sensing galactose in various fields, the review covers biosensors based on the use of galactose oxidase, with a discussion of methods for their immobilization (via cross-linking, adsorption, covalent bonding and entrapment). This is followed by a short section on biosensors based on the use of galactose dehydrogenase. The conclusion section summarizes the state of the art and addresses current challenges. 相似文献
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The paper deals with time-series analysis of one-line traffic measurements in loss systems. Discrete-time stochastic models are derived for finite-capacity trunk groups with non-exponential distributions of interarrival and service times. The modelling accuracy is characterized by a prediction error. Simulation results are used to assert situations when the application of the proposed modelling technique is practical. Finally the adaptive Kalman filter is used to deal with cases when the statistics of observed processes are not known a priori. 相似文献