Studies on the synthesis, characterization and biological activities of some novel Piperazine and Triazole derivatives

Abstract

Abstract A large number of nitrogen containing heterocyclic building blocks have several applications in pharmaceutical research and drug discovery. Among nitrogen containing heterocyclic compounds, piperazines and triazoles have been extensively studied because of their varied physiological properties and extensive therapeutic applications. The present work has two main parts. The first part is synthesis, characterization and evaluation of molecules containing either piperazine or triazole or both rings as anticonvulsant agents. This part consists of synthesis, characterization and anticonvulsant activity of 4-chloro-2-(4-substituted-piperazin-1-yl) quinazoline, 1-(2, 6-difluorobenzyl)-1H-1, 2, 3-triazol-4-yl] (4- substituted- piperazin-1-yl) methanones, [5-chloro-1-(2, 6-difluorobenzyl)-1H-1, 2, 3-triazol-4-yl] (4-substituted piperazin-1- yl) methanones, substituted 2-[5-chloro-1-(2, 6-difluorobenzyl)-1H-1, 2, 3-triazol-4- yl]-1, 3, 4-oxadiazoles and substituted 2-[1-(2, 6-difluorobenzyl)-1H-1, 2, 3-triazol-4- yl]-1, 3, 4-oxadiazoles. The second part consists of synthesis, characterization and evaluation of molecules containing piperazine ring as antibacterial agents. This part comprises of synthesis, characterization and antibacterial activity of 6-fluoro-1- methyl-4-oxo-7-(piperazin-1-yl)-4H- [1, 3] thiazeto [3, 2-a] quinoline-3-carboxylic acid. The synthesized compounds were characterized by using methods like thin layer chromatography, melting points, infra-red spectroscopy, 1HNMR spectroscopy and mass spectroscopy techniques. The synthesized compounds were tested for either anticonvulsant activity or antibacterial activity based on their design and structure. The biological activities were tested using standard screening methods viz. subcutaneous Pentylenetetrazole induced threshold seizure method for determining anticonvulsant activity and evaluation of antibacterial activity using Disk diffusion method. It can be inferred that 4-chloro-2-(4- substituted- piperazin-1-yl) quinazolines with aryl and glycol ether substitution act as anticonvulsant agent. In the case of 1-(2, 6-difluorobenzyl)-1H-1, 2, 3-triazole derivatives with aryl, benzothiazole, methoxy ethanol and ethanol substituted piperazines, aryl and alkyl substitutions in the case of oxadiazoles offered protection against subcutaneous Pentylenetetrazole induced seizure. Hence showing anticonvulsant activity. N-substituted 6-fluoro-1-methyl-4-oxo-7-(piperazin-1-yl)-4H- [1, 3] thiazeto [3, 2-a] quinoline-3-carboxylic acid derivatives with piperazine ring substituted with quinoline ring and with the halogen, cyano substituted phenyl ring has increased inhibitory activity on Gram +ve bacteria.