Synthesis characterisation and pharmacological evaluation of nitrogen and sulphur containing some novel heterocycles and their derivatives

Abstract

Resistance towards available drugs is rapidly becoming a major problem worldwide. The need to design new compounds to counter this resistance problem has become one of the most important areas of research today. Knowledge from medicinal chemistry about the heterocyclic ring system allows us to know that a large number of drugs and biologically relevant molecules which contain heterocyclic ring system are biologically active. Only one divalent hetero atom such as nitrogen, oxygen or sulfur can be incorporated into simple five or six member aromatic heterocycles to improve the biological activity. Various research works has confirmed that the thiadiazole ring system is very useful intermediate/subunit amongst all the heterocycles for the development of newer molecules of pharmaceutical interest. In this research work an attempt has been made to synthesize five member aromatic systems having three hetero atoms at symmetrical positions by using multi-step conventional reaction strategy to yield new derivatives of 1, 3, 4-thiadiazole possessing potential pharmacological activities like analgesic, antipyratic, anti-inflammatory, antimicrobial, antioxidant and anticancer activities. In order to achieve the target, condensation reaction of substituted aryl carboxylic acid was carried out with thiosemicarbazide followed by 2-chloro-N-substituted-phenyl-acetamide, chlorophenyl isocyanate and different amines to obtain 1, 3, 4-thiadiazole derivatives. This condensation reaction was carried out with the idea that all the synthesized 1, 3, 4-thiadiazole derivatives possess significant analgesic, antipyratic, anti-inflammatory, antimicrobial, anti-oxidant and anti-cancer activities. The synthesized compounds have been characterized by IR, 1H-NMR, Mass and Elemental Analysis (C, H, N) study and were evaluated for in-vitro and in-vivo activities. Almost all the compounds were found to have positive responses out of which few were found to be promising in respect to the biological activity studies while some have shown poor respo