- The Stabilities of Meisenheimer Complexes. Part 41. Kinetic Studies of Adduct Formation and Nucleophilic Substitution in the Reactions of Hydroxide Ions with 1-X-3,5-Dinitrobenzenes and with 1-X-4-Chloro-3,5-dinitrobenzenes (X = H, CF3, CO2-) in Water-Dimethyl Sulphoxide Mixtures. T...
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Kinetic and equilibrium measurements are compared for the reactions of (1) and (4) (X = CF3, CO2-, H) with hydroxide ions in dimethyl sulphoxide-water mixtures.The aducts (3), formed from (1), have higher thermodynamic stabilities than their isomers (2) although there is little kinetic discrimination in the rates of hydroxide attack at the three unsubstituted positions.The presence in (4) of the chlorine atom results in a general reduction in the rate of nucleophilic attack, the effect being particularly large for ipso-reaction (attack at the 4-position).Hence the reaction of (4) with base results in the initial formation of adducts (5).Contrary to a recent report the intermediates (6) on the reaction pathway to the phenols (7) are not sufficiently stable to allow spectrophotometric detection.
- Crampton, Michael R.,Greenhalgh, Colin
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- Visible-Light-Induced Radical Polynitration of Arylboronic Acids: Synthesis of Polynitrophenols
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We report a visible light-assisted one-pot method for the synthesis of polynitrophenols through radical tandem hydroxylation and nitration of arylboronic acids by utilizing copper(II) nitrate tri-nitydrate as the nitro source. This method features mild conditions, a simple procedure, and good functional group tolerance. Compared to conventional methods, this work provides a straightforward approach for the polynitration of aromatic compounds.
- Zhang, Qi,Raveendra Babu, Kaki,Huang, Zhouliang,Song, Jinna,Bi, Xihe
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p. 2891 - 2896
(2018/06/20)
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- A simple synthesis of benzimidazole N-oxides from 2-nitroaniline derivatives - Scope and limitations
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Several benzimidazole N-oxide derivatives were synthesized in very good yield by heating at reflux the corresponding N-alkyl-2-nitroaniline derivative with NaOH in 60% 1,4-dioxane-water. The effect of substituents on the aromatic ring and amino group on t
- Bujan, Elba I.,Salum, Maria Laura
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p. 1322 - 1327
(2007/10/03)
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- o-Nitroaniline derivatives - 13. Reactions of N-(o-nitroaryl)sarcosine esters with bases
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The title reactions give 1-hydroxy-4-methylquinoxaline-2,3-diones (4) together with a variety of mono- and bi-cyclic byproducts. All of these may result from a common intermediate, viz. a 1-hydroxy-4-methyl-3,4-dihydro-1H-2,1,4-benzoxadiazine-3-carboxylat
- Collins,McFarlane,Mackie,Smith
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p. 7887 - 7898
(2007/10/02)
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- STUDIES ON FLUORINE CONTAINING HETEROCYCLIC COMPOUNDS: 4. REACTIONS OF 3-NITRO-4-CHLOROBENZOTRIFLUORIDE AND 3,5-DINITRO-4-CHLOROBENZOTRIFLUORIDE WITH FIVE MEMBERED HETEROCYCLES
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The reactions of 3-nitro-4-chlorobenzotrifluoride (1a) and 3,5-dinitro-4-chlorobenzotrifluoride (1b) with heterocycles (2-5) are described.Six S-linked and N-substituted heterocycles (6, 9-11, 13), such as 2-(2-nitro-4-trifluoromethylphenylthio)benzothiazole (9a), were prepared from the reactions of 1a with benzotriazole (2), 2-mercaptobenzothiazole (5a) and 2-mercaptobenzoxazole (5b) and from the reactions of 1b with 2, 1,2,4-triazole (3) and 5a in DMF respectively. 1a reacted with 2-mercaptothiazoline (4) to give the desired product 7 and bis(2-nitro-4-trifluoromethylphenyl) thioether (8). 3-(2-Benzoxazolyl)-2-benzoxazolinethione (15) was obtained from the reaction of 1b with 5b.The spectral data and elemental analyses were fully in accord with the proposed structures, and the possible mechanisms for these compounds and other by-products were discussed.
- Chen, Mei-Jin,Chi, Ching-Sung,Chen, Qing-Yun
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