Rilpivirine

Rilpivirine API Impurity (CAS 500287-72-9) is a structurally related byproduct arising from the synthetic pathway of the parent antiretroviral agent. It retains the core pyridine-pyrimidine-piperazine scaffold but features an unsubstituted piperazine nitrogen, distinguishing it from the fully alkylated parent compound. This impurity is generated during late-stage piperazine ring functionalization, resulting from incomplete ethylation. It serves as a critical HPLC reference standard for quantifying process-derived impurities in rilpivirine drug substance.