Results 11 to 20 of about 5,651,932 (190)

Dynamic Effects May Affect Hammett Linear Free Energy Relationship [PDF]

, 2019
The aromatic nucleophilic substitution reaction in the Clayden rearrangement reaction has an abnormal Hammett linear free energy relationship1. Inspired by the concertedstepwise variation of the aromatic nucleophilic substitution reaction in 20182, we determined the mechanism of Clayden rearrangement reaction under several conditions by DFT calculation
Xinyu Xu, Zongchang Han
core   +3 more sources

Relationship between the electrophilicity and σp Hammett constant in Baeyer–Villiger reactions [PDF]

Chemical Physics Letters, 2008
Abstract The Baeyer–Villiger oxidation of some aldehydes and ketones has been revised by using the electrophilicity as a descriptor of reactivity. The global electrophilicity index evaluated at the ground state of a series of aromatic aldehydes and ketones shows a linear relationship with the σ p Hammett substituent constants.
Meneses, L., Araya, A., Pilaquinga, F., Fuentealba Rosas, Patricio   +3 more
openaire   +2 more sources

Propagation Kinetics of Para-Substituted Styrenes:  A Test of the Applicability of the Hammett Relationship to Free-Radical Polymerization

Macromolecules, 1999
In this work, pulsed laser polymerization measurements of the homopropagation rate coefficients (k(p)) for a series of para-substituted styrene monomers ( 4-X-styrene: X = OCH3, CH3, F, Cl, Br) at 20, 30, and 40 degrees C are reported. On the basis of nonlinear least-squares fits of the Arrhenius model to these data, the following point estimates for ...
Coote, ML, Davis, TP
openaire   +4 more sources

On the analysis of oxidative deamination with the help of the Hammett relationship and other linear free energy relationships

CHIMIA, 1971
E.A. Zeller, M. Hsu, P.K. Li
doaj   +2 more sources

Nickel-Catalyzed Three-Component Difluoroalkylation-Amination for the Direct Access to Anti-Inflammatory β-Difluoroalkyl Amines. [PDF]

Adv Sci (Weinh)
A nickel‐catalyzed three‐component reductive fluoroalkylation‐amination strategy of N‐vinylamides for the direct access to the α‐amidyl‐β‐difluoroalkyl amines was reported here. The synthetic method features with broad substrate scope, mild conditions, high functional group tolerance, and convenience to handle.
Xu C, Ma F, Ding F, Wang L, Li Y, He Y, Zhang X, He S, Liu D.   +8 more
europepmc   +2 more sources

Interdependence of the Hammett and isokinetic relationships: a numerical simulation approach

Monatshefte für Chemie - Chemical Monthly, 2021
Many homologous reaction series present linear correlations between the enthalpy (ΔHo≠,i) and entropy (ΔS o≠,i) of activation (kinetic compensation effect), the slope being the isokinetic temperature of the series (Tiso), so that at T = Tiso, all the reactions of the family share the same value of the rate constant. However, the random errors committed
Joaquin F. Perez-Benito, Arnau Clavero-Masana   +1 more
openaire   +2 more sources

Assessing the nucleophilic character of 2-amino-4-arylthiazoles through coupling with 4,6-dinitrobenzofuroxan: Experimental and theoretical approaches based on structure-reactivity relationships

Journal of Saudi Chemical Society, 2020
A kinetic study of the reactions of potentially bioactive 2-amino-4-arylthiazoles with highly reactive 4,6-dinitrobenzofuroxan (DNBF) is reported herein in acetonitrile solution. The complexation reaction was followed by recording the UV–vis spectra with
Reem A. Alenzi, Nizar El Guesmi, Mohamed R. Shaaban, Basim H. Asghar, Thoraya A. Farghaly   +4 more
doaj   +1 more source

Effects of solvent and structure on the reactivity of 6-substituted nicotinic acids with diazodiphenylmethane in aprotic solvents [PDF]

Journal of the Serbian Chemical Society, 2009
The rate constants for the reactions of diazodiphenylmethane (DDM) with 6-substituted nicotinic acids in aprotic solvents at 30°C were determined. The obtained second order rate constants in aprotic solvents, together with literature data for benzoic and
Drmanić Saša Ž., Marinković Aleksandar D., Jovanović Bratislav Ž.   +2 more
doaj   +3 more sources

Cross-Dehydrogenative Coupling Reactions With Redox-Active Guanidine Reagents. [PDF]

Chemistry
ABSTRACT Cross‐dehydrogenative coupling (CDC) reactions are attractive and environmentally friendly ways to form new C‐C and other element‐element bonds. Here, we report the first CDC reactions triggered by a redox‐active guanidine reagent. N‐phenyltetrahydroisoquinoline and derivatives with electron‐donating and withdrawing substituents at the N ...
Walter P, Hübner O, Himmel HJ.
europepmc   +2 more sources

Kinetic Study of the Reaction of Benzofuroxans with 2-Acetylthiophene: Effect of the Substituents on the Reaction Rate Using Hammett Equation

Orbital: The Electronic Journal of Chemistry, 2020
The present work reports kinetic study of the reaction of benzofuroxan and its derivatives with 2-acetylthiophene. Hammett equation was used to determine the rate of the reaction and substituent effect. Specifically, chloro, nitro and methyl substituted
Intisar Salih Ahmed, Damra Elhaj Mustafa
doaj   +3 more sources