Identification and synthesis of new process impurities of amlodipine, a calcium channel blocker

Abstract Amlodipine belongs to the class of calcium channel blocker that is used to reduce high blood pressure (hypertension). Two related substances of amlodipine namely 3‐(2‐[1.3‐dioxo‐1,3‐dihydro‐2 H ‐isoindol‐2‐yl]ethyl)‐5‐methyl‐(4RS)‐4(2‐chlorophenyl)‐2‐([2‐(1,3‐dioxo‐1,3‐dihydro‐2 H ‐isoin‐dol‐2‐yl)ethoxy]methyl)‐6‐methyl‐1,4‐dihydropyridine‐3,5‐dicarboxylate ( 11 ) and 3‐([2‐aminoethyl]‐5‐aminoethoxy)‐4‐(2‐chlorophenyl)‐1,4‐dihydro‐6‐methylpyridine‐3,5‐dicarboxylate ( 12 ) were identified. The present work describes the origin, synthesis, and characterization of these related substances.