Reactions of Aromatic Nitro Compounds with Bases

Buck, Peter Henry

doi:10.1002/anie.196901201

Cited by 51 publications

(20 citation statements)

References 109 publications

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“…[I.] (19), both inductive and resonance effects of substituent Y would each exert its influence (20). In a 1978 review on nucleophilic displacement of aromatic nitro groups (21), examples were cited that under different experimental conditions for various substrates, selective displacement of the nitro or chloro group, or competitive displacement of both nitro and chloro groups, could take place, but Can fast Y no detailed mechanistic explanations were presented.…”

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confidence: 99%

Studies on some selective and competitive substitution reactions of cyclopentadienyliron complexed chloronitrobenzenes with amines as nucleophiles

Abd‐El‐Aziz¹,

Piórko²,

Lee³

et al. 1989

Can. J. Chem.

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Can. J. Chem. 67, 1618(1989. Nucleophilic substitution reactions of the (q6-0-, -m-, or -p-chloronitrobenzene)(q5-cyclopentadienyl)iron cation (2a, 2b, or 2c, respectively) with aniline, n-butylarnine, or pyrrolidine as nucleophile were investigated. It was found that only selective displacement of the nitro group occurred for reactions with aniline. For reaction with n-butylamine or pyrrolidine, o-isomer 2a resulted in the selective displacement of only the chloro group, giving rise to the (q6-o-n-butylaminonitrobenzene)(q5-cyclopentadieny1)iron cation (5a) or the (q6-o-nitro-~-pyrrolidinylbenzene)(q5-cyclopentadieny1)iron cation (7a), respectively. With the m-or p-isomer 2b or 2c, reaction with n-butylamine or pyrrolidine gave a mixture of substitution products from competitive displacements of both chloro and nitro groups, the major product from the m-isomer being derived from displacement of the chloro group while the major product from the p-isomer resulted from displacement of the nitro group. Possible interpretations of these results on the basis that the basicity of the nucleophile and the combined inductive effects of the nitro and chloro substituents would play important roles are presented.Key words: (q6-o-, -m-, and -p-chloronitrobenzene)(q5-cyclopentadienyl)iron cations, nucleophilic substitution reactions, aniline, n-butylamine, pyrrolidine.ALAA S. ABD-EL-AZIZ, ADAM P I~R K O , CHOI CHUCK LEE et RONALD G. SUTHERI-AND. Can. J. Chem. 67, 1618(1989. On a ktudik les reactions de substitutions nuclkophiles des cations (q6-0-, -m-ou -p-chloronitrobenzbne)(q5-cyclopentadikny1)fer (respectivement 2a, 2b ou 2c) avec l'aniline, la n-butylamine ou la pyrrolidine. On a trouvi que, avec l'aniline, il ne se produit qu'un dkplacement sklectif du groupement nitro. Pour les reactions de la n-butylamine ou de la pyrrolidine avec l'isombre ortho, 2a, on n'observe que le dkplacement sklectif du groupement chloro conduisant respectivement aux cations (q6-o-n-butylaminonitrobenzbne)(q5-cyclopentadiknyl)fer (5a) ou (q6-o-n-nitro-~-pyrrolidinylbenzbne)(q5-cyclopentadiCny1)fer (7a). Avec les isombres mita ou para (2b ou 2c), les rkactions avec la n-butylamine ou la pyrrolidine conduisent 9 des mClanges de produits de substitution provenant des rkactions de substitutions compktitives des groupements chloro et nitro; le produit majeur obtenu 9 partir de l'isombre rne'ta provient de la substitution du groupement chloro alors que le produit majeur obtenu 9 partir de l'isombre para provient de la substitution du groupement nitro. On prksente des interprktations possibles de ces rtsultats qui sont baskes sur les basicitts relatives des nuclkophiles et sur l'hypothbse que les effets inductifs combinks des substituants nitro et chloro joueraient un rBle important.Mots clis : cations (q6-o-, -m-ou -p-chlor~nitr~ben~~ne)(q5-cyclopentadiknyl)fer, rkactions de substitutions nucleophiles, aniline, n-butylarnine, pyrrolidine.[Traduit par la revue]The displacement of the chloro group in the (q6-chlorobenzene) ( q 5-cyclopentadienyl) iro...

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Studies on some selective and competitive substitution reactions of cyclopentadienyliron complexed chloronitrobenzenes with amines as nucleophiles

Abd‐El‐Aziz¹,

Piórko²,

Lee³

et al. 1989

Can. J. Chem.

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“…The capability of aromatic nitro compounds to interact with bases by a number of mechanisms has led to controversy regarding the occurrence and importance of nuclear hydrogen exchange (1)(2)(3)(4)(5)(6). In the case of 1,3-dinitrobenzene (DNB), the species that have been postulated to be formed at different times through action of a base Y: are a charge transfer complex 1, a radical anion 2, covalent adducts (also known as Meisenheimer or o-complexes) 3 and 4, as well as the carbanions 5 and 6 which are the presumed intermediates in proton exchange.…”

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“…A variety of o-complexes which are For personal use only. closely analogous to 3 and 4 have been characterized by nmr as well as uv-vis spectroscopy (1)(2)(3)(4)(5)(6)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). However, there is as yet no unambiguous uv-vis or nmr evidence for the carbanions 5 and 6.…”

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Hydrogen exchange studies. XIV. Kinetics and mechanism of base-catalyzed hydrogen exchange in 1,3-dinitrobenzene in aqueous dimethylformamide and relationship with σ-complex formation

Buncel¹,

Zabel²

1981

Can. J. Chem.

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ERWIN BUNCEL and ALLEN W. ZABEL. Can. J . Chem. 59, 3177 (1981). Kinetic data have been evaluated for hydrogen exchange in 1,3-dinitrobenzene (DNB), occurring at the 2-position, in dimethylformamide (DMF) -D,O mixtures containing deuteroxide ion. The pseudo first order rate constants for exchange, k,,,. show inverse dependence on the initial DNB concentration, which can be quantitatively related to the extent of o-complex formation in these systems. The profile fork,,,, as function of medium compositio~l exhibits a maximum at ca. 70 mol% DMF, and E ,~, for o-complex formation reaches a plateau at about the same medium composition. The equilibrium constants for o-complex formation, K,, are used to calculate the free. or uncomplexed, deuteroxide ion concentrations, which then allow one to calculate k 2 . the second order rate constants for exchange. The k, values show a uniformly increasing tendency with increased DMF content. Correlations with medium basicity are examined, and the nature of the log k, and log K, vs. H-plots afford insight into the origin of the medium dependence of proton exchange. The results of the present study are consistent with the cr-complex being an unreactive form of the substrate towards exchange, which occurs via uncomplexed DNB present in small concentration. The study also rules out the possibility that the colored species present in these systems is the carbanion formed on deprotonation of DNB.ERWIN BUNCEL et ALLEN W . ZABEL. Can. J. Chem. 59. 3177 (1981). O n a evalue les donnees cinetiques de l'echange d'hydrogene se produisant en position 2 du dinitro-1,3 benzene (DNB) dans des melanges de dimethylformamide (DMF) -D,O contenant I'ion deuteroxyde. L a constante de vitesse d e pseudo ordre un de l'echange k,,,, revele un effet inverse de la concentration initiale de DNB qui peut etre relie quantitativement aux taux deformation du complexe o dans ces systemes. 1.e profil de k,,, en fonction de la composition du milieu montre un maximum pour environ 70 molR de DMF et le E, , , de la formation du complexeo atteint un plateau pour environ la meme composition du milieu. On a utilise la constante d'equilibre d e la formation du complexe o K,, pour calculer les concentrations de I'ion deuteroxyde libre. ou non complexe qui permettent de calculer k, la constante d e vitesse d'ordre deux de I'echange. Les valeurs de k2 montrent une tendance d'augmentation uniforme avec la teneur en DMF. On a examine les correlations avec la basicite du milieu; la nature des courbes de log k, et log K, en fonction de H-fournit des renseignements sur I'origine de l'effet du milieu lors de I'echange de proton. Les resultats de la presente etude sont en accord avec un complexe o qui ne donnerait pas de reaction d'echange celui-ci se produisant par I'intermediaire du DNB non complexe present a une concentration faible. L'etude ecarte egalement la possibilite que l'espece coloree presente dans ces systemes soit le carbanion forme par la protonation du DNB.[Traduit par le journal]

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“…When various electron-withdrawing groups (EWGs) such as -NO 2 , -CN, -CF 3 or -SO 2 CF 3 are attached to an aromatic ring, the anionic sigma complex formed from nucleophilic attack is stabilized through delocalization of the negative charge onto the EWG in conjugation with the aromatic nucleus [18]. Due to the importance of this subject, several reviews describe the formation and stabilization of anionic sigma complexes [18][19][20][21][22].…”

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Synthesis, characterization and thermal behavior of 2,4-dinitrophenoxy ethanol as a suitable plasticizer for propellants formulations

Mousaviazar

Keshavarz

Hayaty

et al. 2016

J Therm Anal Calorim

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2,4-Dinitrophenoxy ethanol (DNE) can be considered as a suitable plasticizer for propellants based on cellulose acetate. It was synthesized in two forms, raw and pure products, which were analyzed by FTIR spectroscopy, 1 H-NMR and 13 C-NMR spectroscopy, elemental analysis, gas chromatography, mass spectrometry and high-performance liquid chromatography. Thermal stabilities of the products, impurities in the raw products and the effect of DNE on the thermal behavior of cellulose acetate were investigated using simultaneous thermogravimetry-differential scanning calorimetry. The results suggest that the raw product containing a small amount of impurity has better thermal stability than the pure product.

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Reactions of Aromatic Nitro Compounds with Bases

Cited by 51 publications

References 109 publications

Studies on some selective and competitive substitution reactions of cyclopentadienyliron complexed chloronitrobenzenes with amines as nucleophiles

Studies on some selective and competitive substitution reactions of cyclopentadienyliron complexed chloronitrobenzenes with amines as nucleophiles

Hydrogen exchange studies. XIV. Kinetics and mechanism of base-catalyzed hydrogen exchange in 1,3-dinitrobenzene in aqueous dimethylformamide and relationship with σ-complex formation

Synthesis, characterization and thermal behavior of 2,4-dinitrophenoxy ethanol as a suitable plasticizer for propellants formulations

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