Bicyclic [1,3,4] Thiadiazolo[3,2-α]Pyrimidine Analogues: Novel One-Pot Three-Component Synthesis, Antimicrobial, and Antioxidant Evaluation

A novel one-pot three-component synthesis of 1-(7-methyl-2,5-diphenyl-5H-[1,3,4]thiadiazolo(3,2-alpha)pyrimidine-6-yl)ethanone (4a-i) derivatives via cyclo-condensation of substituted 2-amino-[1,3,4]-thiadiazole (1a-c), acetylacetone (2) and various aromatic aldehydes (3a-c) in the presence of p-toluene sulfonic acid (PTSA) in acetonitrile. Spectral data and elemental analysis have characterized the newly synthesized compounds. The new analogs were screened for their antibacterial and antifungal activities. The majority of the tested compounds displayed significant to moderate efficacy against most of the designated organisms. Among the tested compounds, 4b, 4e, and 4h showed noteworthy efficacy against selected microbes, and compounds 4c and 4i were found to be exceptionally efficient against selected fungal strains. Compound 4c, 4e, 4f, 4i were also designated as best antioxidants against NOx.