(3S, 8S, 9S, 12R)-Atazanavir is a stereoisomeric impurity arising from asymmetric synthesis or racemization during Atazanavir production. It retains the core naphthalenediolsulfonamide scaffold but exhibits inverted configurations at C-3, C-8, C-9, and C-12 relative to the parent drug’s (3R, 8R, 9R, 12S) arrangement. The molecule features a tetrahydrofuran ring fused to a naphthalene core, with a terminal sulfonamide group and a hydroxyl-substituted side chain. This impurity’s distinct stereochemistry alters its metabolic stability and binding affinity. It serves as an HPLC reference standard for quantifying stereoisomeric impurities in Atazanavir APIs.
