Cyclization Reactions of Mono-Thiocarbohydrazones with α-Haloketones: Synthesis and Potential Biological Activities of Substituted 1,3-thiazoles and 1,3,4-thiadiazines

A series of new substituted 1,3-thiazole derivatives 10a-h were prepared via the reaction of monothiocarbohydrazones 8a-h with one equivalent of α-bromoketones in ethanol. Similarly, another series of new substituted 1,3,4-thiadiazines 11a-e were prepared from the reaction of monothiocarbohydrazones 8i,j with one equivalent of α-bromoketones in ethanol. The resulting products were obtained as colored crystals in moderate to good yields. All new compounds are fully characterized by 1H-, 13C-NMR, IR and elemental analysis. Pharmacophore modeling study of four of the synthesized compounds revealed that at least two of them have potential biological activities. Some of these activities will be investigated experimentally in the lab.