Synthesis and Pharmacological Evaluation of Novel Pyrazolyl Piperidine Derivatives as Effective Antiplatelet Agents

The synthesis and antiplatelet activity of substituted pyrazolyl piperidine derivatives (3a–n) are described. These compounds were synthesized by an improved ring opening reaction of 2-arylidene quinuclidinone using hydrazine hydrate under mild conditions. They were characterized and screened for their in vitro antiplatelet profile in human platelet aggregation using adenosine diphosphate as agonist. Investigation of structure activity relation revealed interesting results. Among these synthesized derivatives (3a–n), compounds 3a, 3c, 3j, and 3l exhibited excellent activity, while 3c was the most potent one. Based on IC₅₀ values, it was observed that most of the compounds possessed antiplatelet aggregation activity superior to the reference drug Aspirin.