Purification of 2-methoxyethyl 1-methylethyl 2, 6-dimethyl-4-(3-nitrophenyl)pyridine-3,5-dicarboxylate by preparative high-performance liquid chromatography

Abstract
The 2-methoxyethyl 1-methylethyl 2,6-dimethyl-4-(3-nitrophenyl)pyridine-3, 5-dicarboxylate was obtained in a 99.8% pure form from raw material by preparative-scale high performance liquid chromatography. This compound is an impurity in the industrial process of nimodipine. The chromatographic conditions were optimized to achieve any efficient purification in the shortest time. A reversed-phase preparative-scale HPLC column was used. This work demonstrates how gram quantities of pure material can be conveniently obtained using preparative HPLC, even when the components in a mixture are difficult to resolve.