- Nucleophilicity parameters for carbanions in methanol
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The kinetics of the reactions between eleven carbanions 2a-k (nitronates and malonic acid derivatives) and benzhydrylium ions 1a-g were investigated photometrically in methanol/acetonitrile (91:9, v/v) at 20°C. Since the competing reactions of the benzhyd
- Thanh, Binh Phan,Mayr, Herbert
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- Conversion of nitroalkanes into carboxylic acids via iodide catalysis in water
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We report a new method for the conversion of nitroalkanes into carboxylic acids that achieves this transformation under very mild conditions. Catalytic amounts of iodide in combination with a simple zinc catalyst are needed to give good conversions into the corresponding carboxylic acids.
- Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
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supporting information
p. 1013 - 1016
(2016/01/16)
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- Scalable, easy synthesis, and efficient isolation of arylnitromethanes: a revival of the Victor Meyer reaction
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A modified approach to synthesize and isolate arylnitromethanes is described. The method takes advantage of the significant difference in acidity between the arylnitromethane and the major impurity of the reaction, the nitrite ester. The arylnitromethanes resulting from this process are obtained in high yields and are analytically pure, i.e., they do not require distillation or further purification, which is a comfortable improvement of the ancestral Victor Meyer reaction.
- Alaime, Thibaud,Delots, Audrey,Pasquinet, Eric,Suzenet, Franck,Guillaumet, Gérald
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p. 1337 - 1341
(2017/01/21)
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- Reactions of substituted phenylnitromethane carbanions with aromatic nitro compounds in methanol: Carbanion reactivity, kinetic, and equilibrium studies
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The feasibility of carrying out nucleophilic addition from electron-deficient heteroaromatics has been addressed through a detailed investigation of the interaction of a two 7-substituted-nitrobenzofurazan (R = OMe 2a; R = Cl 2b) with a series of substituted-nitroaryl anions (X = 4-NO 2 1a; X = 3-NO2 1b; X = 4-CN 1c; X = 4-Br 1d), all reactions first lead to the quantitative formation of the σ-adducts 3a-d and 4a-d arising from covalent addition of the nucleophile to the C-5 carbon. The rate and equilibrium constants for the formation of σ-adducts 3a-d and 4a-d (k5, K5) together with the rate constants for their decomposition (k-5) have been determined in methanol at 25C, allowing a determination of intrinsic rate constants, k0 = 0.03, the lower k0 value reflects the very strong salvation by methanol of the negative charge on the nitro group. The discovery of a linear correlation between the E and pKaMeOH parameters allows a calibration of the electrophilicity power of 2a and 2b, E = -11.67 and -10.29, respectively. Applying the general approach to nucleophilicity/electrophilicity recently developed by Mayr et al. through the relationship log k = s(E + N), a successful ranking of our nitroaryl anions 1a-d on the general nucleophilicity scale (N) has been carried out. The N values of 1a-d are found to cover a range from 15.78 to 16.69. The results are compared with previously reported data in water and DMSO.
- Asghar, Basim H.
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p. 477 - 488
(2014/07/08)
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- Nucleophilicities of nitroalkyl anions
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The kinetics of the reactions of eight nitroalkyl anions (nitronate anions) with benzhydrylium ions and quinone methides in DMSO and water were investigated photometrically. The second-order rate constants were found to follow a Ritchie constant selectivi
- Bug, Thorsten,Lemek, Tadeusz,Mayr, Herbert
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p. 7565 - 7576
(2007/10/03)
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