Enzalutamide Impurity D

Enzalutamide Impurity D is a structurally related degradation byproduct formed via hydrolytic cleavage of the parent compound's trifluoromethyl-substituted indazole core, yielding a fluorinated aromatic ring fused to a defluorinated carboxylic acid moiety. This impurity retains a secondary amine linkage but exhibits a truncated aliphatic side chain compared to Enzalutamide. Its distinct electron-withdrawing fluorine substitution and polar carboxylic acid group confer unique chromatographic properties, enabling its use as an HPLC reference standard for quantifying synthetic process impurities in Enzalutamide formulations.