New series of hydrazinyl thiazole derivatives of piperidin-4-one: Synthesis, structural elucidation, analgesic activity and comparative structure activity relationship

Abstract

Seven new hydrazinyl thiazole derivatives of piperidin-4-one (PE3-PE9) have been synthesized by cyclization of intermediate thiosemicarbazone derivative (PE2). Parent molecule (PE1) was synthesized by one pot total synthesis using Mannich condensation reaction. Percent yield of most of the compounds found in between 70-85%. Compounds were identified by spectroscopic analysis. In vivo analgesic activity was examined using tail flick method. one-way ANOVA was used to compare the mean latency time of synthesized derivatives with control and standard. Analgesic activity was discussed in terms of structural differences between compounds. Among all the derivatives thiosemicarbazone derivative showed good analgesic activity (195.24%). Methoxy (-OCH3) and bromo (-Br) containing thiazole derivative also showed good pain reducing property (167.62%, 203%) at a dose of 30mg/kg.