- Relative reactivity and kinetic pattern of aniline and N-methylaniline as nucleophiles in aromatic substitution (SNAr) reactions
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Kinetic results are reported for the reactions of 4-nitrophenyl-2,4,6-trinitrophenyl ether 3 with aniline and N-methylaniline in dimethyl sulphoxide, acetonitrile, methanol, and benzene. The reactions gave the expected 2,4,6-trinitrodiphenylamine and were
- Emokpae, Thomas A.,Isanbor, Chukwuemeka
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- Kinetics of the reaction of phenyl picrates with phenoxide ions in water. Concerted or stepwise?
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A kinetic study is reported of the exchange reactions of substituted phenoxide ions with some ring-substituted 2,4,6-trinitrophenyl ethers in water. The βronsted diagrams formed by plotting log k, where k is the second-order rate constant for reaction, ve
- Crampton, Michael R.,Robotham, Ian A.
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p. 1084 - 1089
(2014/01/06)
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- Leaving group effects on the mechanism of aromatic nucleophilic substitution (SnAr) reactions of some phenyl 2,4,6-trinitrophenyl ethers with aniline in acetonitrile
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Kinetic studies are reported for the reactions with aniline in acetonitrile of a series of X-phenyl 2,4,6trinitrophenyl ethers [X = H, 2-, 3-, 4-CH3,2,4-, 2,6-(CH3)2,2-, 3-, 4-NO 2,2,4-, 2,6-(NO2)2]. X-ray crystal structures for X = H, 2,6-(CH3)2 and 2,6-(NO2) 2 are reported and provide evidence for steric crowding around the 1-position of these molecules. Nevertheless, the kinetic data show that increasing substitution does not sterically inhibit nucleophilic attack by aniline and an 'early' transition state is likely. In general, the reactions are base catalysed; interpreted as rate-limiting deprotonation of the zwitterionic intermediates. Only with the dinitro derivatives is an uncatalysed reaction involving intramolecular proton transfer observed and when X = 2,6-(NO2)2 this pathway takes all the reaction flux. Copyright
- Crampton, Michael R.,Emokpae, Thomas A.,Howard, Judith A.K.,Isanbor, Chukwuemeka,Mondal, Raju
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- Kinetic studies of σ-adduct formation and nucleophilic substitution in the reactions of ethyl 2,4,6-trinitrophenyl ether, some phenyl 2,4,6- trinitrophenyl ethers, and phenyl 2,4-dinitronaphthyl ether with aniline in dimethyl sulfoxide
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The reaction of ethyl 2,4,6-trinitrophenyl ether with aniline in dimethyl sulfoxide containing Dabco occurs in two stages. The first gives 5, the σ-adduct intermediate on the substitution pathway, which has been identified spectroscopically. The second yields 2,4,6-trinitrodiphenylamine, the substitution product. Kinetic studies show that proton transfer is rate limiting both in the formation of the intermediate and in its subsequent acid-catalysed decomposition. Phenoxide is a considerably better leaving group than ethoxide and the substitution reactions of phenyl 2,4,6- trinitrophenyl ethers and phenyl 2,4-dinitronaphthyl ether with aniline in DMSO occur without the accumulation of intermediates. The kinetics indicate both uncatalysed and base-catalysed pathways. The kinetic and equilibrium data for reaction of the ethyl and phenyl ethers are compared with data for σ-adduct formation from 1,3,5-trinitrobenzene and aniline.
- Crampton, Michael R.,Robotham, Ian A.
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p. 627 - 634
(2007/10/03)
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- AUTOCOMPLEXES OF THE PICRYL SERIES WITH A ONE-MEMBERED O-BRIDGE
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A series of new autocomplexes of the picryl series with a one-membered bridge were synthesized from picryl chloride and a series of substituted phenols.The relationships governing intramolecular charge transfer in the synthesized compounds were studied by
- Il'ina, I.G.,Zabaznova, S.V.,Ivanova, E.V.,Butin, K.P.
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p. 295 - 297
(2007/10/02)
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