ANTIBACTERIAL ACTIVITY OF NOVEL HYDROXY SUBSTITUTED BENZOTHIAZOLE DERIVATIVES AGAINST STREPTOCOCCUS PYOGENES

Abstract

Synthesis and screening of benzothiazole derivatives have great importance in heterocyclic chemistry because of its potent and significant biological activities against Streptococcus (S) pyogenes especially hydroxy substitution at benzothiazole. Hydroxy-substituted benzothiazole derivatives were synthesized by reaction of 4-amino-2-chlorophenol with potassium thiocyanate under temperature control and presence of bromine in glacial acetic acid and ammonia. Hydroxy-substituted nitrobenzamides then synthesized by condensation of 2-amino-4-chlorobenzothiazol-5-ol with 2(3or4)- nitrobenzoylchloride acid in presence of dry pyridine and acetone. Finally, newly synthesized derivatives (A-01 to A-09) were synthesized through replacing of chlorine of nitrobenzamide by reaction with 2-nitroaniline, 3-nitroaniline, and 4-nitroaniline in presence of DMF. Analytical characterization was performed by TLC, melting point, IR and NMR spectra. Antibacterial activity was performed against S. pyogenes by cup plate method (diffusion technique) using procaine penicillin as standard. Compound A-03, A-04 and A-08 showed potent antibacterial activity against S. pyogenes at both concentrations 50µg/ml and 100µg/ml as compared to standard while the rest of compounds showed moderate to negligible activity when further assessed to determine MIC by broth dilution method.