Design and synthesis of novel 1,3,4-thiadiazole thioglycosides as promising antimicrobial potent structures.

Thiosemicarbazide was used as a key starting material for the building of a diversity of novel heterocyclic moieties. The heterocyclization reaction of thiosemicarbazide derivatives with carbon disulfide in basic conditions afforded novel heterocyclic 1,3,4-thiadiazolethiolate derivatives. 1,3,4-thiadiazole-2-thiol was successfully reacted with protected α-D-gluco- and galacto-pyranosyl bromides in dimethylformamide at room temperature to give the matching 1,3,4-thiadiazole S-glycosides in good yields. The latter compounds were reacted with ammonia-methanol at room temperature for 10 min, and the deprotected derivatives were obtained in good yields. The newly synthesized compounds were characterized by basic analyses and spectral information (IR,¹H NMR, and ¹³C NMR, X-ray). All newly produced compounds were evaluated and screened for their antibacterial activities. Compound 6f proved to be the most active antimicrobial among the investigated heterocycles.