Velpatasvir Intermediate-I-SR-Isomer

Velpatasvir Intermediate-I-SR-Isomer is a stereoisomeric impurity arising from the enantioselective synthesis of the antiviral agent velpatasvir. It features a pyrazine-fused tetrahydropyridine core with an SR-configuration at the chiral center adjacent to the amino substituent, differing from the parent drug's R configuration. This structural inversion introduces a diastereomeric impurity that requires quantification during API purification. The compound serves as an HPLC reference standard for monitoring enantiomeric purity in velpatasvir manufacturing processes.