Clopidogrel

Clopidogrel is a thieno[3,2-c]pyridine derivative characterized by a 2-chlorophenoxy substituent linked via a methylene bridge to the thienopyridine core. The structure includes a 4H-lactam moiety fused to the pyridine ring, conferring rigidity and metabolic stability. Its sulfonamide-like sulfur bridges the thienyl and pyridine rings, while the chlorinated aromatic ring introduces electronic asymmetry. As the parent API, it undergoes hepatic biotransformation to produce the active thiol metabolite. This compound serves as the reference standard for HPLC quantification of clopidogrel in drug product assays.