DES (N-(Methoxycarbonyl)) Velpatasvir

DES (N-(Methoxycarbonyl)) Velpatasvir is a synthetic impurity derived from velpatasvir via methoxycarbonylation at the nitrogen atom of the pyridine ring, introducing an ester functionality (COOCH3) in place of the parent compound's amine. Its core structure retains a fused tetrahydrothiophene and substituted pyridine moiety, with the methoxycarbonyl group conferring distinct chromatographic and spectroscopic properties. This impurity is utilized as an HPLC reference standard for quantifying process-related impurities in velpatasvir active pharmaceutical ingredient (API) batches.