Synthesis and characterization of N-(N-benzoyl thioureido)- 1,3,4- thiadiazoline compounds of biological interest

Abstract

Thiourea derivatives represent well known important group of organic compounds due to diverse application in the field medicine, agriculture, coordination and analytical chemistry. On the other hand thiadiazoline moiety also have important biological properties at the same time is an important synthetic precursors. In this dissertation we have designed and successfully synthesized thiourea derivatives and obtained fruitful result of their biological activity as potential antibacterial agents.

On the outset of our work, attempts were made to synthesize thiadiazoline derivatives simply by refluxing substituted benzoic acid and thiosemicarbazide in one pot process and good to moderate yield was obtained. The key starting material benzoylisothiocyanate was prepared by refluxing benzoyl chloride and ammoniumthiocyanate in dry benzene for 12 hours. The benzoylisothiocyanate was oily mass and was not stable for long time. So, crude oily mass was used to the next attempt to get the target compounds.

The target compounds thiouriedo derivatives were synthesized by simply stirring equimolar mixture of benzoylisothiocayanate and thiadiazole derivatives in DMF at room temperature for eight hours and obtained a good yield. All the thiouriedo derivatives were characterized by IR, 1H NMR and 13C NMR spectral evidences.

The antibacterial properties of thiouriedo derivatives showed less to moderate activities in different bacterias. The synthesized compounds and their biological activities are summarized in the following tables.