Synthesis of some salicylic acid derivatives and determination of their acidity constants

Several derivatives of salicylic acid have been synthesized by the condensation reaction of methyl salicylate with α,ω-diols and α,ω-diamines, and the acidity constants of five newly prepared derivatives have been determined in 61.10% aqueous ethanol using potentiometric titration method. In order to avoid calibration of pH-meter, the standard potential of glass electrode was determined from the titration data. The results obtained are discussed with regard to different resonance effects of the ester oxygen and the amide nitrogen atoms.