Background: In the present study, fourteen new 1,2,4-triazole Schiff bases and eight new 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines incorporating a pyrimidine ring were synthesized and evaluated for their antibacterial activity.
Methods: 1,2,4-Triazole Schiff bases were prepared from the condensation of 4-amino-3-mercapto-5- (2-thiomethylpyrimidyl)-1,2,4-triazole with a series of arylaldehydes in the presence of (+)-tartaric acid as catalyst. On the other hand, the reaction of 4-amino-3-mercapto-5-(2-thiomethylpyrimidyl)-1,2,4- triazole with substituted phenacyl bromides afforded the corresponding 1,2,4-triazolo[3,4-b][1,3,4]- thiadiazines.
Results: The structures of 1,2,4-triazole Schiff bases and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines were characterized by IR, NMR and mass spectral data. All the synthesized compounds were screened for their antibacterial activities using 96-well microbroth dilution assay.
Conclusion: Schiff base with p-hydroxylphenyl substituent and triazolothiadiazine containing 4- flurophenyl ring displayed moderate antibacterial activity against Pseudomonas aeruginosa at MIC 62.5 μg/ml.
Keywords: 1, 2, 4-Triazole, pyrimidine, Schiff base, triazolothiadiazine, condensation, antibacterial.