Maravirov MAR Endo isomer

Maravirov MAR Endo isomer is a stereoisomeric impurity arising from asymmetric synthesis of the parent CCR5 antagonist. It features a cyclopropylmethyl sulfonamide core with endo-configuration at the bridged bicyclic scaffold, differing from the exo-geometry in the active drug. The compound retains the N-(cyclopropylmethyl) sulfonamide pharmacophore but exhibits altered conformational flexibility due to the inverted stereochemistry at the spiro junction. This isomer is a critical HPLC reference standard for quantifying stereoisomeric purity in Maravirov drug substance batches.