2919-12-2Relevant academic research and scientific papers
Anilinolysis of nitro-substituted diphenyl ethers in acetonitrile: the effect of some ortho-substituents on the mechanism of SNAr reactions
Isanbor., Chukwuemeka,Emokpae, Thomas A.
, p. 37 - 49 (2010)
Rate data are reported for the reactions of a series of X-phenyl 2,4,6-trinitrophenyl ethers 1a-e [X = H, 4-NO2,2-NO2, 2,4-(NO2)2, or 2,6-(NO2)2] with substituted anilines 2a-e [Y = H, 2-CH
Steric and electronic effects on the mechanism of nucleophilic substitution (SnAr) reactions of some phenyl 2,4,6-trinitrophenyl ethers with aniline and N-methylaniline in acetonitrile and in dimethyl sulfoxide
Isanbor, Chukwuemekh,Emokpae, Thomas A.,Crampton, Michael R.
, p. 2019 - 2024 (2002)
Rate data are reported for the reactions of a series of 3′- and 4′-substituted phenyl 2,4,6-trinitrophenyl ethers, 4, with aniline in acetonitrile, leading to 2,4,6-trinitrodiphenylamine. The main reaction flux occurs through a base catalysed pathway invo
Modification of the Order of Reaction and Reaction Rate of Nucleophilic Aromatic Substitution in Micellar Solutions
Lelievre, Joel,Haddad-Fahed, Omaima,Gaboriaud, Rene
, p. 2301 - 2310 (1986)
The rate of formation of 2,4,6-trinitrodiphenylamine following the attack of aniline on 1-methoxy-2,4,6-trinitrobenzene has been studied in micellar media.The partial order with reference to the nucleophilic reagent (aniline) is unity in solutions of cationic detergents (positive micelles) and 3/2 in water or solutions of anionic detergents.For such reactions there are two main steps in the reaction scheme: first, the formation of an adduct between reagents, favoured by the effect of local higher concentration in the two kinds of micellar solutions and secondly, ejection of a proton from the adduct formed.The latter reaction is catalysed largely by positive micelles and in this case the kinetics are not limited by the deprotonation step.On the other hand, negative micelles inhibit the ejection of a proton and this opposes, in part, the effect of higher local concentrations.
The synthesis of vinylogous amidine heterocycles
Labarbera, Daniel V.,Skibo, Edward B.
, p. 11887 - 11895 (2014/01/06)
We report herein a convenient synthetic methodology for the conversion of meta-dinitro heterocyclic rings to iminoquinones with vinylogous amidine functionality. These structures are found in nature, particularly in marine organisms, and may be important
Anilinolysis of picryl benzoate derivatives in methanol: Reactivity, regioselectivity, kinetics, and mechanism
Ibrahim, Mahmoud F.,El-Atawy, Mohamed A.,El-Sadany, Samir K.,Hamed, Ezzat A.
supporting information, p. 551 - 559 (2013/08/23)
The reaction of picryl benzoate derivatives 1a-g with aniline in methanol proceeds through CO-O and Ar-O bond cleavage pathways. Furthermore, the reactivity of these esters toward anilinolysis is correlated to the energy gap between highest occupied molecular orbital aniline and lowest unoccupied molecular orbital of each ester. The regioselectivity of acyl-oxygen versus aryl-oxygen cleavage is also discussed. The overall rate constants k tot split into kCO-O (the rate constant of acyl-oxygen cleavage) and kAr-O (rate constant of aryl-oxygen cleavage). The CO-O bond cleavage advances through a stepwise mechanism in which the formation of the tetrahedral intermediate is the rate-determining step. The Ar-O bond cleavage continues through a SNAr mechanism in which the departure of the leaving group from the Meisenheimer complex occurs rapidly after its formation in the rate-determining step.
The influence of some steric and electron effects on the mechanism of aromatic nucleophilic substitution (SNAr) reactions in nonpolar solvent
Emokpae, Thomas A.,Atasie, Nkechi V.
, p. 744 - 750 (2008/04/18)
Kinetic studies are reported for the reactions with aniline in benzene of a series of X-phenyl 2,4,6-trinitrophenyl ethers [X = H; 2-, 3-, 4-CH 3; 2,4-, or 2,6-(CH3)2] 1a-f, and the results compared with those of the corre
Catalytic effects of hydrogen-bond acceptor solvent on nucleophilic aromatic substitution reactions in non-polar aprotic solvent: Reactions of phenyl 2,4,6-trinitrophenyl ether with amines in benzene-acetonitrile mixtures
Banjoko, Olayinka,Babatunde, Ibitola A.
, p. 8035 - 8040 (2007/10/03)
The effect of addition of small amounts of hydrogen-bond acceptor solvent, acetonitrile, to the benzene medium of the reactions of phenyl 2,4,6-trinitrophenyl ether with aniline and cyclohexylamine, respectively have been investigated. The addition produc
Leaving group effects on the mechanism of aromatic nucleophilic substitution (SnAr) reactions of some phenyl 2,4,6-trinitrophenyl ethers with aniline in acetonitrile
Crampton, Michael R.,Emokpae, Thomas A.,Howard, Judith A.K.,Isanbor, Chukwuemeka,Mondal, Raju
, p. 65 - 70 (2007/10/03)
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
Relative reactivity and kinetic pattern of aniline and N-methylaniline as nucleophiles in aromatic substitution (SNAr) reactions
Emokpae, Thomas A.,Isanbor, Chukwuemeka
, p. 188 - 196 (2007/10/03)
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
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.
