Determination of pK-Values of Some Barbituric Acid Derivatives

Abstract

Practical dissociation constants (μ = 0.1, 25°C) of the following barbituric acids (pK₁, pK₂) were determined spectrophotometrically: 5-pivaloyloxy-5-(1-phenylethyl) - (7.0; 12.1); 5-hydroxy-5-(1-phenyethyl) - (7.8; 12.0); N-methoxymethy 1 -5-phenyl-5-ethyl (7.3₅; -); N-methyl -5-phenyl -5-ethyl - (7.8; -); 5-phenyl-5-ethyl - (7.3₅; 12.3). Structures were attributed to individual ionic forms involved.