Synthesis and antibacterial activity of new Sulfamethoxazole derivative.

Abstract

In the present work, diazonium salt was synthesized by treatment of the primary aromatic amine of sulfomethoxazole with sodium nitrite, which is directly coupled with m-cresol to give a new sulfamethxazole derivative. Chemical structure of the new derivative was characterized by physical and spectroscopic techniques as UV, FTIR, 1H NMR and 13C NMR spectra. The new derivative [4-(salycilic acid-5”-azo-yl)-N-(5`-methyl-3`-isoxazolyl)benzene-sulfonamide] is characterized by its it is lack of the primary aromatic amine in its structure with no possibility to form hydroxylamine metabolite; which is responsible for allergic reactions; In addition, the new derivative is more water soluble due to the presence of azo- linkage. The new sulfomethoxazole derivative proved to have no antibacterial activity against Pathogenic isolates of G- bacteria (E. coli) used in the present work, and reliable in vitro antibacterial activity against G+ bacteria (Staphyllococcus aureus). Mean IC50 against pathogenic Staph aureus isolates used in the study was about 12µg/ml whereas the mean MIC was 20 µg/ml. Presence of azo-bond may change the mode of action of sulfamethoxazole, make it possible to test this a new compound as new antibacterial agent against G+ bacteria.