The gem Effect. III. The Influence of 3-Mono- and 3-gem Substitution on the Acid Dissociation Constants of Glutaric Acid. A Comparison of the Sensitivity of [UNK]pKaof Dicarboxylic Acids and the Rate of Ring Closure of Their Monoesters to the Intramolecular Distance Separating Carboxyl Functions

1965 ◽  
Vol 87 (21) ◽  
pp. 4851-4855 ◽  
Author(s):  
Thomas C. Bruice ◽  
William C. Bradbury
Keyword(s):  
Glutaric Acid ◽  
Dissociation Constants ◽  
Dicarboxylic Acids ◽  
Ring Closure ◽  
Acid Dissociation ◽  
Acid Dissociation Constants ◽  
Intramolecular Distance

Substituent effects on polarographic reduction of some photographic color intermediates

1976 ◽  
Vol 54 (8) ◽  
pp. 1205-1210 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Bahgat E. El-Anadouli
Keyword(s):  
Dissociation Constants ◽  
Substituent Effects ◽  
Protonated Form ◽  
Acid Dissociation ◽  
Polarographic Reduction ◽  
Substituent Constant ◽  
Acid Dissociation Constants ◽  
Controlled Potential Electrolysis ◽  
Half Wave ◽  
Controlled Potential

Polarographic reduction of two series of benzoylacetanilides has been investigated in 40% (by volume) ethanolic Britton–Robinson buffers. One series (A) contains substituents on the anilide moiety, and the second (B) has substituents on both the anilide and benzoyl moieties. Polarographic controlled-potential electrolysis data indicate that the electroactive species in both series is the protonated form (ArCOCH2CONHAr′)H+. The reduction half-wave potentials of anilides of series A were found to be independent of the nature of the substituent, whereas those of series B show a good linear relationship when plotted vs. the σ substituent constant of the substituent on the benzoyl moiety (ρ = 0.284, r = 0.995). Values of the acid dissociation constants of the keto (K1) and enol (K2) tautomers of the anilides of series A were calculated; unlike their E1/2 values, the pK1 data show a linear correlation with the Hammett substituent constant, σ. The pK2 values show, however, little variation with σ.

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