rilpivirine Iodo impurity

Rilpivirine Iodo impurity is a structurally related API impurity characterized by an iodine substitution at the 5-position of the pyridine ring within the rilpivirine core scaffold. This compound retains the pyrimidine-cyclopropyl linkage but incorporates an iodo group, altering electronic properties and synthetic pathway fidelity. It arises as a trace byproduct during late-stage synthesis due to competitive halogenation. This impurity serves as a critical HPLC reference standard for quantifying process-related deviations in rilpivirine formulations.