Results 161 to 170 of about 12,998 (208)

Mechanism of photocatalytic oxidation of amino acids: Hammett correlations

Catalysis Today, 2014
Abstract Amino acids are important constituents of microorganisms and organic matter in water and may contribute to generation of nitrogenous disinfection by-products (N-DBPs) during chlorination and chloramination. The photocatalytic oxidation of amino acids has thus been carried out to seek their mineralization and to understand their interactions ...
Virender K. Sharma, Jincai Zhao, Hisao Hidaka   +2 more
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Utilisation des correlations de hammett a l'etude des equilibres tautomeres

Analytica Chimica Acta, 1972
The acidity constants for various substituted benzoic acids and anilinium cations have been measured potentiometrically in aqueous dimethylsulphoxide media at 20°. The values obtained (pKXS) are compared with the corresponding values for aqueous media (pKXE).
Jean-Claude Halle, Robert Schaal
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Expanding the Hammett Correlations for the Vinylheptafulvene Ring‐Closure Reaction

European Journal of Organic Chemistry, 2017
A selection of 2,3‐diarylated photochromic dihydroazulenes (DHAs) was prepared by following two different protocols. The first protocol relies on the synthesis of a 3‐bromo‐substituted dihydroazulene, which is subjected to a Suzuki cross‐coupling reaction in the final step.
Martin Drøhse Kilde, Mia Harring Hansen, Søren Lindbæk Broman, Kurt V. Mikkelsen, Mogens Brøndsted Nielsen   +4 more
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Hammett ϱσ correlation for reactions of horseradish peroxidase compound II with phenols

Archives of Biochemistry and Biophysics, 1986
The rates of reduction of horseradish peroxidase compound II by p-methoxyphenol (4-hydroxyanisole) have been studied from pH 6.0 to 10.5. The kinetics are influenced by an acid group of pKa 8.7 on compound II. The acidic form of compound II is reactive; the basic form is not. Only the electrically neutral, unionized form of p-methoxyphenol is reactive.
H B, Dunford, A J, Adeniran
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A hammett correlation for the addition of organotin hydride to benzaldehydes

Journal of Organometallic Chemistry, 1972
Abstract The relative rates for tri-n-butyltin hydride additions to substituted benzaldehydes under free radical and polar conditions have been determined from competitive reactions. The relative rates have been correlated by the Hammett σ or σ+ constants. The polar addition is correlated best by σ and the free radical addition by σ+. Interpretations
Gilbert L. Grady, John R. Saucier, William J. Foley, Daniel J. O'hern, William J. Weidmann   +4 more
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ChemInform Abstract: REACTIVITY OF AN AMBIPHILIC CARBENE. A NONLINEAR HAMMETT CORRELATION

Chemischer Informationsdienst, 1982
AbstractAus dem Chlor‐methoxy‐diazirin (I) entsteht thermisch das Carben (II), dessen Addition an die Styrole (III) zu den Cyclopropanen (IV) untersucht wird.
R. A. MOSS, W. GUO, K. KROGH‐JESPERSEN
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Hammett pσ correlation for reactions of lactoperoxidase compound II with phenols

Canadian Journal of Chemistry, 1993
A stopped-flow kinetic study shows that the reaction rates of lactoperoxidase compound II with substituted phenols are greatly dependent upon the substituent on the benzene ring. Of the 15 phenols studied, it has been possible to relate the reaction rate constants with the ionization constants of 11 phenols by a linear Hammett free-energy relationship:
Hongchang Zhang, H. Brian Dunford
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Correlation of stability constants of metal complexes with hammett's σ-factor

Journal of Inorganic and Nuclear Chemistry, 1966
Abstract A parameter is derived on thermodynamical grounds, which measures the variations in the stability of the metal complexes formed with a series of aromatic ligands, when the basicity of these ligands is altered by changes in substituents. This parameter is shown to be a linear function of Hammett's σ-factor for the substituents, using several
J.J.R.Fraústo da Silva, J.Gonçalves Calado   +1 more
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Stereochemical Control Factors in the Hantzsch Thiazole Synthesis:  A Hammett Substitution Correlation Analysis

Organic Letters, 2001
[reaction--see text] It is possible to correlate the distribution of stereochemical products produced during a Hantzsch thiazole synthesis according to the Hammett free-energy equation. This analysis confirms the presumed control of the rate of epimerization during thiazole formation due to stabilization of a cationic transition state intermediate ...
Q, Qiao, S S, So, R A, Goodnow
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Developing a Modern Approach To Account for Steric Effects in Hammett-Type Correlations

Journal of the American Chemical Society, 2016
The effects of aryl ring ortho-, meta-, and para-substitution on site selectivity and enantioselectivity were investigated in the following reactions: (1) enantioselective Pd-catalyzed redox-relay Heck reaction of arylboronic acids, (2) Pd-catalyzed β-aryl elimination of triarylmethanols, and (3) benzoylformate decarboxylase-catalyzed enantioselective ...
Celine B, Santiago, Anat, Milo, Matthew S, Sigman   +2 more
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