(3R,8S,9S,12S)-Atazanavir is a stereoisomeric impurity of the HIV protease inhibitor Atazanavir, characterized by inverted configurations at C3, C8, C9, and C12 relative to the parent compound. Its core structure comprises a 2,3-dihydro-1,4-benzodioxin-5-ylmethyl moiety linked to a 3-hydroxy-4-phenylbutanoic acid side chain, with a sulfonamide group at C9 and a pyridine ring at C1. The compound retains the naphthalene scaffold but exhibits altered stereochemistry at key chiral centers, leading to reduced pharmacological activity. This impurity arises during asymmetric synthesis steps and serves as a critical HPLC reference standard for chiral purity analysis in Atazanavir formulations.
