Velpatasvir R Isomer (Methoxy Methyl)

Velpatasvir R Isomer (Methoxy Methyl) is a stereoisomeric impurity derived from the antiviral agent velpatasvir, featuring an (R)-configured chiral center at the piperazine-fused tetrahydrofuran core. The methoxymethyl (MOM) group is appended to the 4-position of the tetrahydrofuran ring, introducing steric hindrance that alters its pharmacokinetic profile relative to the parent compound. This isomer arises via enantioselective synthesis or racemization pathways during API manufacturing. Its distinct diastereomeric configuration enables chromatographic differentiation, serving as a critical HPLC reference standard for impurity profiling in velpatasvir drug substance analysis.