4732-14-3Relevant academic research and scientific papers
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
Crampton, Michael R.,Robotham, Ian A.
, p. 627 - 634 (2007/10/03)
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.
Kinetic and equilibrium studies of σ-adduct formation and nucleophilic substitution in the reactions of trinitro-activated benzenes with aliphatic amines in acetonitrile
Crampton, Michael R.,Lord, Simon D.
, p. 369 - 376 (2007/10/03)
Rate and equilibrium constants are reported for reactions in acetonitrile of butylamine, pyrrolidine and piperidine with 1,3,5-trinitrobenzene, 1, and with ethyl 2,4,6-trinitrophenyl ether, 4a, and phenyl 2,4,6-trinitrophenyl ether, 4b. Rapid nucleophilic attack at unsubstituted ring-positions may yield anionic σ-adducts via zwitterionic intermediates, while slower attack at the 1-position of 4a and 4b may lead to substitution to give 2,4,6-trinitroaniline derivatives. Base catalysis in the substitution reaction reflects rate-limiting proton transfer which may be from the zwitterionic intermediates to amine in the case of 4b, or from a substituted ammonium ion to the ethoxy leaving group in the case of 4a. Comparisons with values in DMSO indicate that values of overall equilibrium constants for adduct formation are ca. 104 lower in acetonitrile, while rate constants for proton transfer are ca. 104 higher. These differences may reflect strong hydrogen-bonding between DMSO and -NH+ protons in ammonium ions and in zwitterions. In acetonitrile homoconjugation of substituted ammonium ions with free amine is an important factor.
Kinetic and Equilibrium Studies of ?-Adduct Formation and Nucleophilic Substitution in the Reactions of Hydroxide Ions with 2,4,6-Trinitrophenyl Sulfides and Ethers
Chamberlin, Rachel,Crampton, Michael R.,Knight, Roland L.
, p. 2986 - 2998 (2007/10/02)
Kinetic and equlibrium data are reported for reaction of hydroxide ions in 20/80 DMSO/water (v/v) with a series of 4'-substituted phenyl 2,4,6-trinitrophenyl sulfides, 1, and with ethyl thiopicrate, 2, ethyl picrate, 3, phenyl picrate, 4, and 1,3,5-trinitrobenzene, 5.In each case a rapid reaction is observed involving reversible hydroxide addition at an unsubstituted ring-position.In the case of 1-4 this is followed by slower, irreversible attack at the 1-position leading to the formation of picric acid.The Hammett ρ value for equilibrium addition of hydroxide to the 3-position of 1 is 0.98, and the ρ value for rate constants for attack at the 1-position is 0.62.The results are discussed in terms of the electronic and steric effects of the 1-substituents.Comparison of 1-5 indicates that changing from an OR to SR group introduces additional steric crowding.However for the reactions studied changing from R = Et to R = Ph has little steric consequence.
The Stabilities of Meisenheimer Complexes. Part 39. Steric Effects on Rate and Equilibrium Constants for ?-Adducts Formation from Alkyl 2,4,6-Trinitrophenyl Ethers and Ethoxide Ions in Ethanol
Cooney, Aidan,Crampton, Michael R.
, p. 1793 - 1796 (2007/10/02)
Rate and equilibrium data are reported for reactions of ethoxide ions in ethanol with four alkyl 2,4,6-trinitrophenyl ethers to give isomeric 1,3 and 1,1 ?-adducts.The results indicate the importance of streric factors in this series.Increasing the size of the alkyl substituent causes decreases in values of k3, the rate coefficient, and K3, the equilibrium constant, for reaction at the unsubstituted 3-position, and also causes decreases in values of k1 for reaction at the substituted position.
The Stabilities of Meisenheimer Complexes. Part 34. Kinetic Studies of ?-Adduct Formation and Nucleophilic Substitution in the Reactions of 2,4,6-Trinitrophenetole with Aliphatic Amines in Dimethyl Sulphoxide
Crampton, Michael R.,Routledge, Paul J.
, p. 573 - 582 (2007/10/02)
The reaction of 2,4,6-trinitrophenetole with aliphatic amines in dimethyl sulphoxide results in the formation of anionic ?-adducts via zwitterionic intermediates.Rapid attack at the 3-position is followed by attack at the ethoxy-substituted 1-position.The 1-adducts formed by reaction with n-butylamine and benzylamine undergo acid-catalysed expulsion of ethoxide to yield N-substituted picramides; that formed by reaction with piperidine is relatively stable.Rate and equilibrium data for these reactions have been determined and compared with data for reactions of related compounds.Increased steric crowding at the reaction centre caused by a change from primary amines to piperidine results in reductions in the rate of proton transfer from zwitterionic intermediates to amine catalyst and in the rate of leaving-group expulsion.
KETONITRONE ESTERS AND THEIR KETALS IN THE ALKYLATION OF SALTS OF NITROPHENOLS AND THE CORRESPONDING MEISENHEIMER COMPLEXES
Drozd, V. N.,Grandberg, N. V. (Tokmakova),Udachin, Yu. M.
, p. 1082 - 1089 (2007/10/02)
A study has been carried out of the formation of ethers in the alkylation of the silver salts of nitrophenols by alkyl halides, and of the corresponding cyclic ketals of the ketonitrone ethers in the alkylation of alkali metal salts of Meisenheimer comple
ACTION OF NITRIC ACID ON 2,4,6-TRINITROPHENYL ARENE AND ALKANECARBOTHIOATES
Nurgatin, V. V.,Sharnin, G. P.,Savel'eva, L. A.,Nurgatina, R. B.
, p. 2167 - 2169 (2007/10/02)
For the case of the reaction of S,S'-bis(2,4,6-trinitrophenyl)dithiooxalate with concentrated nitric acid it was found that the sulfur-containing groups in the esters of thiocarboxylic acids are substituted by hydroxy and nitroso groups.The reaction, which is accompanied by copious release of nitrogen oxides and increase in temperature, leads to 2,4,6-trinitrophenol or 2,4,6-trinitronitrosobenzene.The structure of the latter was confirmed by IR and UV spectroscopy and by oxidation to 1,2,3,5-tetranitrobenzene. 2,4,6-Trinitrophenyl benzenecarbothioates give the nitroderivative only when the acids contain not more than one nitro group in the phenyl radical.The nitroso group in 2,4,6-trinitronitrosobenzene, like the halogen in picryl halides, is readily substituted by the action of nucleophilic reagents.
