Investigation of the lipophilic properties of phenylanthranilic acid

Reactivity of phenylanthranilic acids derivatives. Xxiii. Synthesis and acid-base properties of 4,5-dymethoxy-n-(2´-carboxyphenyl)anthranilic acids

“…As a continuation of a number of papers [4,[12][13][14][15][16][17][18][19] related to the study of reactivity of biologically active substituted N-phenylanthranilic acids, dissociation of 4,5-dimetoxy-N-(2´-carboxyphenyl)anthranilic acids (5a-f) has been examined according to the equation.…”

“…Ionization constants of 4,5-dymethoxy-N-(2´-carboxyphenyl)anthranilic acids have been determined by potentiometric titration in the binary solvent of dioxane-water (60 vol% of dioxane) at 25ºC (Scheme 2) [18,19]. The given method allows to obtain concen- tration of рКа only.…”

“…Probably, it is connected with the different distance between carboxyl groups and substitutes in the ring В. It should be noted that appearance of another reactive centre does not practically influence upon sensitivity (within the limits of experimental error ρ ІІ corresponds to ρ from the other isostructural series of N-phenylanthranilic acids) [12,13,[18][19][20]. For balance І sensitivity of the reactive centre is sufficiently high because of closeness of substitutes.…”