Synthesis and Characterization of 1,2,4-Triazole- Pyridine Hybrids as Potential Antimicrobial Agents

A novel 1,2,4-Triazole-Pyridine hybrid derivatives was synthesized by the reaction of nicotinohydrazide with carbon disulfide to yield potassium-3-pyridyl-dithiocarbazate (I). This was further cyclized with ammonia solution to yield 5-mercapto-substituted 1,2,4-Triazole-Pyridine hybrid (II). This was finally reacted with different substituted benzyl derivatives to produce 1,2,4-Triazole-Pyridine hybrid derivatives (III). Purity of the derivatives was confirmed by thin layer chromatography and melting point. Structure of these derivatives was set up by determining infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectroscopy. Further, the synthesized derivatives were evaluated for their in vitro antibacterial activity against the two gram-negative bacteria ( Escherichia coli (MTCC 443), Pseudomonas aeruginosa (MTCC 424)) and two gram positive bacteria (Staphylococcus aureus (MTCC 96), Streptococcus pyogenes (MTCC 442), and antifungal activity against the Aspergillus niger (MTCC 282), Aspergillus clavatus (MTCC 1323), Candida albicans (MTCC 227) by cup-plate method. Out of all synthesized derivatives, two derivatives i.e. 3-(5-(3-nitrobenzylthio)-4H-1,2,4-triazol-3-yl)pyridine and 3-(5-(3,5-dinitrobenzylthio)-4H-1,2,4-triazol-3-yl)pyridine showing more potent antibacterial activity while 3-(5-(2,4-dinitrobenzylthio)-4H-1,2,4-triazol-3-yl)pyridine showing more potent anti fungal activity.