Electrochemical Investigation of the Redox Behavior of Isoquinoline Alkaloid Emetine

CPE generated multiple oxidation products, and subsequent high-resolution LC–QTOF–MS/MS analysis revealed ten emetine-associated products (P1–P10). Tentative structural assignments for P1–P8 encompassed dehydrogenated, oxygenated/dehydrogenated, and nitrogen-containing products, whereas P9 and P10 remained structurally unresolved. Together with complementary spectroscopic evidence, these findings support a mechanistic model in which emetine oxidation is initiated at amine functionalities and adjacent benzylic carbon centers, followed by competing dehydrogenation, oxygen incorporation, and secondary product-forming reactions.

This study establishes a mechanistic framework for emetine electrooxidation and demonstrates the utility of integrating electrochemistry with high-resolution mass spectrometry to investigate the oxidative chemistry of bioactive isoquinoline alkaloids.