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1.
T. M. Prokop’eva V. A. Mikhailov M. K. Turovskaya E. A. Karpichev N. I. Burakov V. A. Savelova I. V. Kapitanov A. F. Popov 《Russian Journal of Organic Chemistry》2008,44(5):637-646
Bis(dialkylamide)hydrogen dibromobromates were synthesized and their reactivity was investigated in decomposition of diethylphosphonic, diethylphosphoric, and 4-toluenesulfonic acids 4-nitrophenyl esters. The nucleophilic reactivity of a typical α-nucleophile, hypobromite ion, is independent of the source of the active bromine. The cetyltrimethylammonium dibromobromate is a unique reagent for destruction of ecotoxicants. In weakly alkaline media the half-life of 4-nitrophenyl diethylphosphonate did not exceed 6 s at [BrO?] 0.02 mol l?1, and the apparent reaction rate compared to water increased ~40-fold. The main factor governing the micellar effects of surfactants is concentrating the substrate in the micellar pseudophase. 相似文献
2.
Sadovskii Yu. S. Solomoichenko T. N. Kas'yan A. O. Golodaeva E. A. Anikanova S. V. Kas'yan L. I. Savelova V. A. 《Russian Journal of Organic Chemistry》2004,40(1):50-56
The nucleophilic reactivity of amines of the norbornane, norbornene, and adamantane series toward ptoluenesulfonyl chloride and diphenyl chlorophosphate in acetonitrile at 25°C is determined mainly by the steric factor. Parameters characterizing spatial accessibility of the reaction center in the amine molecule have been determined. Cage-like substituents show no appreciable effect on the amine reactivity, as compared to common alkyl groups. 相似文献
3.
Popov A. F. Lobanova O. V. Savelova V. A. Sadovskii Yu. S. Solomoichenko T. N. Piskunova Zh. P. 《Russian Journal of Organic Chemistry》2002,38(11):1624-1628
For amides belonging to series RCONH2 (I), RCONHMe (II), RCONHPh (III), and RCONMe2 (IV) rate constants k1 (l mol-1 s-1) were determined (in acetonitrile at 25°C) specifying the nucleophilic reactivity of the oxygen atom in amides toward benzoyl chloride and diphenyl chlorophosphate. The lack of substrate selectivity in the reactions in question was established. For equal values of inductive constants * of the R substituents the reactivity sequence of amides with respect to both substrates is the same (I >>
IV >
II, and III >
II), and it does not follow the corresponding sequence of basicities. A conclusion was drawn that both groups of reactions proceed through cyclic transition states resembling reagents: six-membered with amides I and III, and five-membered with amides II and IV. 相似文献
4.
Simanenko Yu. S. Popov A. F. Karpichev E. A. Prokop'eva T. M. Savelova V. A. Bunton C. A. 《Russian Journal of Organic Chemistry》2002,38(9):1314-1325
1-Cetyl-3-(2-hydroxyiminopropyl)imidazolium chloride and bromide were synthesized for the first time. These compounds are functionalized zwitterionic surfactants which give rise to micelle formation in aqueous solution. Kinetic and thermodynamic analysis of nucleophilic cleavage of p-nitrophenyl p-toluenesulfonate, diethyl p-nitrophenyl phosphate, and ethyl p-nitrophenyl ethylphosphonate in the presence of 1-cetyl-3-(2-hydroxyiminopropyl)imidazolium halide micelles showed that the latter are powerful nucleophilic reagents whose kinetic behavior can be described in terms of a simple pseudophase distribution model. The efficiency of substrate solubilization with zwitterionic surfactant micelles and the reactivity of the oximate fragment in the micelle phase were estimated on a quantitative level. The observed acceleration of SN2 reactions with the examined p-nitrophenyl esters relative to analogous reactions of zwitterionic 1-methyl-3-(2-hydroxyiminopropyl)imidazolium halides is, respectively, 12800, 550, and 900 times; it is explained mainly by increased concentration of the reactants in micelles. 相似文献
5.
T. N. Solomoichenko Yu. S. Sadovskii T. M. Prokop’eva E. A. Karpichev I. V. Kapitanov Zh. P. Piskunova V. A. Savelova A. F. Popov 《Theoretical and Experimental Chemistry》2006,42(6):364-370
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.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 6, pp. 357–363, November–December, 2006. 相似文献
6.
N. I. Burakov A. L. Kanibolotskii G. Yu. Osichenko V. A. Mikhailov V. A. Savelova V. V. Kosmynin 《Russian Journal of Organic Chemistry》2001,37(9):1210-1219
N,N-Dialkylcarboxamides react with halogens in the absence of water to form complexes which are likely to have an ionic structure with the Hlg+ ion coordinated at the carbonyl oxygen atom. These products can be isolated as individual compounds. Complexes with bromine undergo further transformations to afford bis-dialkylamide hydrogen tribromide and the corresponding -bromo amide. When the reaction is carried out in the presence of water, the products are only bis-dialkylamide hydrogen tribromides; here, the N-alkyl groups act as a source of protons. 相似文献
7.
In this review we present a summary and correlation of research results obtained in several different approaches aimed at
increasing the efficiency and selectivity of nucleophilic reactions, namely the α-effect in aqueous media and specific interactions
in nontraditional systems such as “melts” of salts, microemulsions, micelles, and liquid/liquid and liquid/solid interfacial
systems.
L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, 70 R. Lyuksemburg
ul., Donetsk 340114, Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 35, No. 1, pp. 1–16, January–February,
1999. 相似文献
8.
V. A. Savelova Yu. S. Sadovskii T. N. Solomoichenko T. M. Prokop’eva V. V. Kosmynin Zh. P. Piskunova C. A. Bunton A. F. Popov 《Theoretical and Experimental Chemistry》2008,44(2):101-108
Peroxocarbonate ions HCO 4 ? and CO 4 2? , which are formed in the H2O2/NH4HCO3/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. 相似文献
9.
V. A. Savelova A. F. Popov L. N. Vakhitova T. N. Solomoichenko Yu. S. Sadovskii T. M. Prokop'eva A. V. Skrypka B. V. Panchenko 《Russian Journal of Organic Chemistry》2005,41(12):1773-1781
Nucleophilic reactivity of hydroxide and hydroperoxide ions toward ethyl 4-nitrophenyl ethylphosphonate, diethyl 4-nitrophenyl phosphate, 4-nitrophenyl 4-toluenesulfonate, and 4-nitrophenyl dimethylcarbamate in the system H2O2-KOH was studied in aqueous-alcoholic solutions at 25°C. The rate of reactions of both anions with ethyl 4-nitrophenyl ethylphosphonate, diethyl 4-nitrophenyl phosphate, and 4-nitrophenyl dimethylcarbamate and of hydroxide ion with 4-nitrophenyl 4-toluenesulfonate increases with rise in the fraction of the alcohol in mixtures of water with isopropyl and tert-butyl alcohols, while the reaction rate of hydroperoxide ion with 4-nitrophenyl 4-toluenesulfonate decreases. The rate of reactions of both anions with all the above substrates in mixtures of water with ethylene glycol decreases as the fraction of the latter rises. The apparent rate of the reaction of ethyl 4-nitrophenyl ethylphosphonate with anionic nucleophiles in the system H2O2-HO?-HCO 3 ? in water at pH 8.5 almost does not depend on the concentration of ammonium hydrogen carbonate up to a value of 1 M, and it increases when the NH4HCO3 concentration exceeds 1 M. Mixtures of water with the lower monohydric alcohols were recommended for use as components of H2O2-HO?-HCO 3 ? systems for oxidative decomposition of ecotoxicants. 相似文献
10.
T. M. Prokop''eva Yu. S. Simanenko I. P. Suprun V. A. Savelova T. M. Zubareva E. A. Karpichev 《Russian Journal of Organic Chemistry》2001,37(5):655-666
The kinetics of the reaction of oximate ions with 2,4-dinitrophenyl p-toluenesulfonate, 4-nitrophenyl p-toluenesulfonate, diethyl 4-nitrophenyl phosphate, and ethyl 4-nitrophenyl ethylphosphonate in H2O-DMSO mixtures (0 to 95 vol % of DMSO) cannot be described in terms of a single Bro/nsted equation. Regardless of the nature of the reaction center and leaving group, both in water and in 80% DMSO fast leveling of the reactivity of oximate ions is observed, the -effect decreases at pK
a 9.0 and disappears at pK
a 12.0 owing to difference in the solvation of weakly (pK
a 9.0) and strongly basic (pK
a 9.0) oximate ions rather than to change of the transition state. Just unfavorable solvation effects are responsible for the fact that the limiting nucleophilic reactivity of oximate ions (as typical -nucleophiles) is not higher than the reactivity of strongly basic alkoxide ions. 相似文献