Velpatasvir intermediate II- SS isomer (Crude)

Velpatasvir intermediate II-SS isomer (Crude) is a stereoisomeric byproduct arising during the synthesis of the NS5A inhibitor Velpatasvir. It features a sulfonamide-linked heterocyclic core with a distinct SS configuration at the chiral centers, differing from the parent drug's R configuration. The compound retains key pharmacophoric elements, including a pyrazine ring and a piperazine moiety, but exhibits altered stereochemistry affecting its pharmacokinetic profile. This isomer serves as a critical HPLC reference standard for monitoring enantiomeric purity during Velpatasvir production.