Structural effects on the acidity of E-α-phenyl-β-arylacrylic acids

The dissociation equilibrium constants of some is-α-phenyl-β-arylacrylic acids (Ar = 2-pyridyl, 3-pyridyl, 4-pyridyl, 1-naphthyl, 2-naphthyl, anthracen-9-yl) have been measured in 80% aqueous 2-methoxyethanol at 25°. The pKa values of these acids, together with those of p-substituted phenyl, 2-furyl, 2-thienyl and selenophen-2-yl derivatives, have been rationalized by an equation involving separate contributions of polar, conjugative and steric effects of heterocycles. The pKa values of some E-α-phenyl-β-alkylacrylic acids (alk = methyl; ethyl; n-propyl; i-propyl; n-butyl; i-butyl) are also reported.

[1]  D. Sciotto,et al.  The dissociation constants of the E- and Z-αβ-diarylacrylic acids , 1980 .

[2]  A. Mamo,et al.  Acid- and base-catalyzed isomerization of cis-1,2-diarylacrylonitriles , 1979 .

[3]  M. Charton.  Steric effects. 6. Hydrolysis of amides and related compounds , 1976 .

[4]  M. Charton,et al.  Steric effects. I. Esterification and acid-catalyzed hydrolysis of esters , 1975 .

[5]  H. Jering,et al.  Proteinase catalyzed resynthesis of the peptide bond Lys 15--Ala 16 in the derivative of trypsin-kallikrein inhibitor (Kunitz) with this peptide bond hydrolyzed. , 1974, Angewandte Chemie.

[6]  R. C. Parish,et al.  Transmission of substituent effects in anthracene. Acid dissociation constants of 10-substituted-9-anthroic acids and substituent chemical shifts of 10-substituted-9-fluoroanthracenes. Evidence for the .pi. inductive effect , 1971 .

[7]  W. Simon.  Structure and Acidity of Organic Compounds , 1964 .

[8]  R. Ketcham,et al.  The Preparation of and Equilibrium between Substituted α-Phenyl-cis- and trans-cinnamic Acids , 1963 .

[9]  C. Watnick,et al.  Derivatives of cis- and trans-3-Stilbazoles , 1962 .

[10]  K. Ponsold,et al.  Untersuchungen über Stilbene, XXVI. Unsymmetrische Diaryl-äthylene , 1960 .

[11]  H. Zimmerman,et al.  Overlap Control of Carbanionoid Reactions. II.1 The Stereochemistry of the Perkin Reaction and Related Condensation Reactions , 1959 .

[12]  F. Fringuelli,et al.  Tellurophene and Related Compounds , 1977 .

[13]  P. Tomasik,et al.  Applications of the Hammett Equation to Heterocyclic Compounds , 1976 .

[14]  S. Fisichella,et al.  Conformational analysis of some (E)-α-phenyl-β-(2-thienyl)- and -(2-furyl_acrylic acids , 1975 .

[15]  G. Marino.  Electrophilic Substitutions of Five-Membered Rings , 1971 .

[16]  R. A. Dybas,et al.  Photochemical cyclizations. I. Preparation of benzo [f] quinolines by photolysis of 2-stilbazole derivatives , 1970 .

[17]  K. Nilsson,et al.  Steric Hindrance in Alkyl-Substituted Atropic Acids. , 1965 .

[18]  H. Brown,et al.  A Quantitative Treatment of Directive Effects in Aromatic Substitution , 1963 .

[19]  B. Datta,et al.  780. Synthesis of polycyclic compounds. Part VII. A shorter route to indeno(2′,3′-1,2)phenanthrene and its analogues , 1962 .

[20]  B. Bak,et al.  Complete determination of the structure of pyridine by microwave spectra , 1958 .

[21]  G. A. R. Kon,et al.  1-Phenyl-2-naphthyl-and 1: 2-dinaphthyl-ethylenes. , 1948, Journal of the Chemical Society.

[22]  M. Flett.  Characteristic infra-red frequencies and chemical properties of molecules , 1948 .

[23]  R. Preuss,et al.  Über Derivate des 5-Brom-1-naphtaldehyds und des 1-Naphtaldehyds. (3. Mitteilung über Naphtaldehyde) , 1941 .