Rosuvastatin 3S,5R-Isomer

Rosuvastatin 3S,5R-Isomer is a stereoisomeric impurity arising from the pyrimidine-fused sulfone core of the parent drug, characterized by opposite configurations at the C-3 and C-5 chiral centers. Its structure incorporates a fluorinated benzene ring, a sulfone linkage, and a hydrazide moiety, with altered spatial orientation affecting intermolecular interactions. This isomer is generated during asymmetric synthesis or racemization pathways, differing from the pharmacologically active 3R,5S-enantiomer. It serves as a critical HPLC reference standard for quantifying enantiomeric purity in Rosuvastatin formulations.