Thiadiazole

The earlier sources of drugs were from plant, animal and mineral sources, but due to the lack of potential action and definitive cure and sometimes more toxicity, the discovery of new drugs that are more potential and less toxic is essential. The synthesis of derivatives has been an important part and is aimed at modifying the action of drugs, particularly to reduce the side effects and to potentiate the drug action. Today more than 60% drugs used in practice are synthesized derivatives and day-by-day the scope of synthetic medicinal chemistry is broadening. The substituted 1,3,4-thiadiazole moieties are already known for different biological activities. Here we have synthesized some novel 1,3,4-thiadiazole analogues combining with different substituted aromatic and aliphatic system with view to get a good antibacterial activity withless toxicity and side effects. All the synthesized compounds were screened for antibacterial activity. As expected 1,3,4thiadiazole derivatives exhibited significant and moderately antibacterial when compared with standard drugs. Therefore in search of new generation of the active compounds, it maybe worthwhile to explore the possibility in this area by introducing different Functional groups or by cyclization as substitutions which may result into better pharmacological agent.

The structural and therapeutic diversity coupled with commercial viability of small heterocyclic molecules has fascinated organic and medicinal chemist. So, a great deal of research was carried out in the field of heterocyclic containing sulphur and nitrogen, because of their immense biological importance. The thiadiazole derivatives posses’ different pharmacological and biological activity. Hence, the search for never effective antimicrobial agents is imperative. It focuses on the problems of cross resistance and better activity against variety of infections. The majority of 1, 3, 4-thiadiazoles are based on the cyclisation of thiaosemicarbazide derivative incorporating this basic structural unit. The structure of new compounds prepared during present investigation has been authentically established by their IR, 1H NMR and Mass spectral studies. The antimicrobial activity of thiadiazole derivatives also reported some of these derivatives exhibit significant and broad spectrum antimicrobial activity. All the synthesized compounds were screened for antibacterial activity against Bacillus subtilis, Bacillus pumilus, E coli and Pseudomonas aureginosa by Disc diffusion method using ciprofloxacin as a standard against Gram positive and Gram negative bacteria. Key Words: Thiadiazole, Thiosemicarbazide, Antimicrobial, Cyclization, Screening 

In the present study, a series of N-[5-(phenyl)-1,3,4-thiadiazole-2-yl] benzamide and N-[5-(phenyl)-1,3,4-thiadiazole-2-yl] acetamide were prepared by refluxing with benzoyl chloride and acetyl chloride with 5-phenyl-1,3,4-thiadiazole-2-amine. 5-phenyl-1,3,4-thiadiazole-2-amine were prepared by oxidative cyclization of thiosemicarbazone (through condensation of aromatic aldehyde and thiosemicarbazide). The structure of new compounds prepared during present investigation have been authentically established by their IR,1H-NMR and Mass spectral studies. The antibacterial and antifungal activities of thiadiazole derivatives also reported. Some of these derivatives exhibit significant antimicrobial activity. Key words:  Thiosemicarbazone, Thiadiazole, antibacterial, antifungal.