LEDIPASVIR CHIRAL IMPURITY 4 [(1S,3R,4R) LedipasvirIntermediate]

LEDIPASVIR CHIRAL IMPURITY 4 [(1S,3R,4R)] is a stereoisomeric byproduct arising from the enantioselective synthesis of ledipasvir, featuring a tetrahydroisoquinoline core with (1S,3R,4R) configuration at chiral centers. Its structure incorporates a 4-aminopyrazine moiety linked to a thiophene ring via a sulfonamide bridge, differing from the parent drug by spatial arrangement of substituents. This impurity exhibits distinct diastereomeric interactions during API purification, necessitating chiral HPLC resolution. It serves as a critical reference standard for quantifying enantiomeric purity in ledipasvir formulations.