Synonyms: Warfarin Sodium Imp. B (EP), Warfarin Imp. B (EP), 4-Hydroxy-2H-1-benzopyran-2-one, 4-Hydroxycoumarin, 4-Coumarinol, 4-Hydroxy-2H-benzo[b]pyran-2-one, 4-Hydroxychromen-2-one, Benzotetronic acid, NSC 11889, Warfarin Sodium Impurity B, Warfarin Impurity B