Notes

Abstract

IT has been shown 1s that o-halogeno-phenylosotriazoles and -benzoic acids undergo dehalogenation by copper powder, it being suggested that the triazole ring acted as an electron-attracting group, rendering the o-halogen atom more reactive. To study the influence of substituents on the strength of triazolecarboxylic acids, the apparent dissociation constants of 2-m-and 2-@-carboxyphenyl-lJ2 ,3-triazole and of some 2-arylphenyl-lJ2,3-triazole-4-carboxy1ic acids have been determined and compared with those of substituted benzoic acids. The dissociation constants of a few triazolecarboxylic acids were determined previouslyJ3 but these did not include the 2-phenyl derivatives. Owing to the sparing solubility of the acids in water, their dissociation constants were determined in the solvent system 4 : 1 w/w Methylcellosolve-water.4 The results are shown in the Table.