Synthesis of some bis- and mono-2-hydroxybenzoic acid derivatives and the determination of their acidity constants

Several bis- and mono-2-hydroxybenzoic acid derivatives were synthesized by the reaction of methyl 2-hydroxybenzoate with some alcohols (diols, polyols and amino alcohols) and their acidity constants were determined in 60% aqueous ethanol by the potentiometric titration method. It has been shown that the biochemical behaviour of these compounds is greatly dependent on then acidity. It appears that the ester derivatives are weaker acids than the amide derivatives and, therefore, can be potentially more involved in the processes of metal ions transport in plants, whereas the introduction of -OH and -??3 groups has a veiy small effect on the biochemical properties.