The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Masao Tokuda - One of the best experts on this subject based on the ideXlab platform.
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Facile and stereoselective synthesis of (E)-vinyl bromides by microwave-induced reaction of 1,1-dibromoalkenes using a Diethyl Phosphonate/EtONa/EtOH system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
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facile and stereoselective synthesis of e vinyl bromides by microwave induced reaction of 1 1 dibromoalkenes using a Diethyl Phosphonate etona etoh system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
A. F. Popov - One of the best experts on this subject based on the ideXlab platform.
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Cleavable dicationic surfactant micellar system for the decomposition of organophosphorus compounds
Theoretical and Experimental Chemistry, 2012Co-Authors: T M Zubareva, T. M. Prokop’eva, A V Anikeev, E A Karpichev, A. N. Red’ko, A. F. PopovAbstract:A dimeric (gemini) surfactant containing cleavable ester groups has been synthesized and studied. The new surfactant has a low critical micelle concentration (2.7∙10^–5 mol/L) and Krafft temperature (≤0°C). Alkaline hydrolysis of 4-nitrophenyl Diethyl Phosphonate and 4-nitrophenyl Diethyl phosphate in the presence of micelles of gemini surfactant I proceeds 30-144 times more rapidly than in water. Chemical cleavage of gemini surfactant I in an alkaline medium is achieved in 96 h.
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catalysis of the alkaline hydrolysis of 4 nitrophenyl Diethyl Phosphonate by cationic dimeric surfactant micelles
Theoretical and Experimental Chemistry, 2011Co-Authors: T M Zubareva, A V Anikeev, E A Karpichev, I V Kapitanov, T M Prokopeva, A. F. PopovAbstract:Dimeric (gemini) surfactants containing hydroxyl functional groups have been synthesized and studied. These new surfactants have low critical micelle formation concentrations (<5·10 −5 mol/L) and Krafft temperatures (≤0 °C). Depending on the pH of the medium, the alkaline hydrolysis of 4-nitrophenyl Diethyl Phosphonate, which is a model of organophosphorus ecotoxicants, proceeds 20–80 times more rapidly in the presence of gemini surfactant micelles than in water.
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Catalysis of the alkaline hydrolysis of 4-nitrophenyl Diethyl Phosphonate by cationic dimeric surfactant micelles
Theoretical and Experimental Chemistry, 2011Co-Authors: T M Zubareva, T. M. Prokop’eva, A V Anikeev, E A Karpichev, I V Kapitanov, A. F. PopovAbstract:Dimeric (gemini) surfactants containing hydroxyl functional groups have been synthesized and studied. These new surfactants have low critical micelle formation concentrations (
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Nucleophilic activity of peroxyhydrocarbonate and peroxocarbonate ions relative to 4-nitrophenyl Diethyl Phosphonate
Theoretical and Experimental Chemistry, 2008Co-Authors: V. A. Savelova, Yu. S. Sadovskii, T. N. Solomoichenko, T. M. Prokop’eva, V. V. Kosmynin, Zh. P. Piskunova, C. A. Bunton, A. F. PopovAbstract:Peroxocarbonate ions HCO _4 ^− and CO _4 ^2− , which are formed in the H_2O_2/NH_4HCO_3/HO^− system, react with 4-nitrophenyl Diethyl Phosphonate (I) through a nucleophilic mechanism with rate constants $$ k_{HCO_4^ - } = 0.008 $$ and $$ k_{CO_4^{2 - } } = 0.13 L/mol \cdot s $$ . Comparison of these constants with the corresponding constants of other inorganic anions in their reaction with I in the framework of the Brönsted equation indicates that HCO _4 ^− and CO _4 ^2− are typical α -nucleophiles.
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Micellar effects of surfactants in cleavage of 4-nitro-phenyl Diethyl Phosphonate by hydroperoxide anion
Theoretical and Experimental Chemistry, 2006Co-Authors: T. N. Solomoichenko, V. A. Savelova, Yu. S. Sadovskii, T. M. Prokop’eva, Zh. P. Piskunova, E A Karpichev, I V Kapitanov, A. F. PopovAbstract:We have studied the nucleophilicity of the hydroperoxide anion relative to 4-nitrophenyl Diethyl Phosphonate (NPDEPS) in the presence of cetyltrimethylammonium bromide (water, 25 °C) while varying the acidity of the medium and the hydroperoxide anion concentration over a broad range. The increase in the reaction rate when the reaction is transferred to a micellar pseudophase is as high as ∼10-fold, which is explained by concentration effects. In CTAB micelles, as in water, the hydroperoxide ion is one of the most effective α-nucleophiles, and the size of the α -effect, characterized by the ratio of the second-order rate constants for reactions of HOO^− and OH^− anions with NPDEPS, remains practically constant and reaches a value of ∼50-fold.
Chunxiang Kuang - One of the best experts on this subject based on the ideXlab platform.
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Facile and stereoselective synthesis of (E)-vinyl bromides by microwave-induced reaction of 1,1-dibromoalkenes using a Diethyl Phosphonate/EtONa/EtOH system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
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facile and stereoselective synthesis of e vinyl bromides by microwave induced reaction of 1 1 dibromoalkenes using a Diethyl Phosphonate etona etoh system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
Hisanori Senboku - One of the best experts on this subject based on the ideXlab platform.
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Facile and stereoselective synthesis of (E)-vinyl bromides by microwave-induced reaction of 1,1-dibromoalkenes using a Diethyl Phosphonate/EtONa/EtOH system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
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facile and stereoselective synthesis of e vinyl bromides by microwave induced reaction of 1 1 dibromoalkenes using a Diethyl Phosphonate etona etoh system
Tetrahedron, 2002Co-Authors: Chunxiang Kuang, Hisanori Senboku, Masao TokudaAbstract:(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a Diethyl Phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
Marek Sochacki - One of the best experts on this subject based on the ideXlab platform.
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Differentiation of Diastereoisomers of Protected 1,2-Diaminoalkylphosphonic Acids by EI Mass Spectrometry and Density Functional Theory
Journal of The American Society for Mass Spectrometry, 2013Co-Authors: Ewelina Drabik, Roman Błaszczyk, Tadeusz Gajda, Grzegorz Krasiński, Marek Cypryk, Marek SochackiAbstract:Electron ionization mass spectrometry and density functional theory (DFT) calculations have been used to study the fragmentation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids. The loss of a diethoxyphosphoryl group and the elimination of Diethyl Phosphonate were found to be competitive fragmentation processes, which can be used to differentiate both stereoisomers. Selective deuterated analogs and product- and precursor-ion mass spectra allowed the elucidation of the fragmentation mechanisms. The structures of the transition states and product ions were optimized using the density functional theory (DFT), and free energy calculations confirmed the observed differences in the formation and relative intensities of specific fragment ions. Figure ᅟ
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Differentiation of Diastereoisomers of Protected 1,2-Diaminoalkylphosphonic Acids by EI Mass Spectrometry and Density Functional Theory
Journal of the American Society for Mass Spectrometry, 2013Co-Authors: Ewelina Drabik, Roman Błaszczyk, Tadeusz Gajda, Grzegorz Krasiński, Marek Cypryk, Marek SochackiAbstract:Electron ionization mass spectrometry and density functional theory (DFT) calculations have been used to study the fragmentation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids. The loss of a diethoxyphosphoryl group and the elimination of Diethyl Phosphonate were found to be competitive fragmentation processes, which can be used to differentiate both stereoisomers. Selective deuterated analogs and product- and precursor-ion mass spectra allowed the elucidation of the fragmentation mechanisms. The structures of the transition states and product ions were optimized using the density functional theory (DFT), and free energy calculations confirmed the observed differences in the formation and relative intensities of specific fragment ions.
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Stereochemical effects in fragmentation of diastereoisomers of protected Diethyl 1,2‐diamino‐alkylPhosphonates
Rapid Communications in Mass Spectrometry, 2010Co-Authors: Ewelina Drabik, Roman Błaszczyk, Tadeusz Gajda, Marek SochackiAbstract:: Diastereoisomers of Diethyl 5-substituted (2-thioxo-imidazolidin-4-yl)Phosphonates, which can be regarded as protected Diethyl 1,2-diaminoalkylPhosphonates, have been analyzed by electron ionization mass spectrometry. Significant differences in the fragmentation of cis- and trans-diastereoisomers were found. The stereospecificity of the elimination of Diethyl Phosphonate and the loss of the diethoxyphosphoryl group were studied using specific labeled compounds and collision-induced dissociation. The relative abundances of ions formed via these fragmentation processes can be used for differentiation of both diastereoisomers.