Clopidogrel Carboxylic acid

Clopidogrel Carboxylic acid is a thienopyridine derivative featuring a 2-chlorothiophene ring fused to a pyridine moiety, substituted with a carboxylic acid group at the terminal acyl chain. This impurity arises from the hydrolytic cleavage of the ester functionality in the parent drug, retaining the core scaffold but replacing the acetyl group with a carboxylic acid. The compound exhibits a zwitterionic character due to the adjacent amine and carboxylic acid functionalities, enhancing its polarity relative to Clopidogrel. It serves as a critical HPLC reference standard for quantifying process-related impurities in Clopidogrel active pharmaceutical ingredient synthesis.