Synthesis and Antibacterial Activity of 4-Methylsalicylic Acid Derivatives and Salicylanilides

Two bromo substituted 4-methylsalicylic acid and an ethyl salicylate derivatives were synthesized by bromination of 4-methylsalicylic acid with N-bromosuccinimde (NBS) and esterification of 4-methylsalicylic acid in the presence of concentrated sulfuric acid. Also, three salicylanilides were synthesized by reacting salicylic acid with various substituted anilines in the presence of acid catalyst. These compounds were characterized by using ¹H NMR, ¹³C NMR, FT-IR spectroscopy, and mass spectral analysis. In vitro antibacterial studies of resultant compounds were carried out by using well diffusion assay against two bacterial strains Streptomyces sp. and Dickeya sp. Among the synthesized derivatives, 4-(bromoethyl)-2-hydroxybenzoic acid displayed higher antibacterial activity against Gram positive Streptomyces sp. while the derivative ethyl-2-hydroxy-4-methylbenzoate showed best antibacterial activity against Gram negative Dickeya sp.