Synthesis and Evaluation of Antibacterial Activity for Some New 1,5-Disubstituted Tetrazoles Containing Benzothiazole and Thiadiazole moieties


In this work new 1,5-disubstituted tetrazoles containing 1,3,4-thiadiazole, benzothiazole moieties and azo group have been synthesized. At first, 2-aminobenzothiazole was converted to the corresponding azoaldehyde derivatives 1 via coupling reaction of its diazonium salt with 2- hydroxybenzaldehyde, which dissolved in sodium hydroxide solution, as coupling reagent. Next, the resulting azoaldehyde derivative 1 was introduced in acid-catalyzed condensation reactions with both 2-amino-5-mercapto-1.3,4-thiadiazole and 2-aminobenzothiazole to give two azoimine derivatives 2 and 3 containing 1,3.4-thiadiazole and benzothiazole moieties, respectively. Later, the resulting azoimines 2 and 3 were introduced in [3+2] cycloaddition reactions with sodium azide in tetrahydrofuran to obtain two new 1,5-disubstituted tetrazoles 4 and 5, respectively.The structures of new synthesized tetrazoles have been confirmed using the spectroscopic means including FT-IR, 1H NMR and Mass. The new synthesized tetrazoles have been tested for their antibacterial activity against two types of bacteria, Staphylococcus aureous (Gram-positive) and Escherichia coli (Gram-negative), The results indicated that both synthesized tetrazoles showed medium activity against Gram-positive bacteria. On the other hand, both tetrazoles showed no effect against Gram-negative bacteria.