3-Bromobenzoic Acid Methyl Ester-d4, is the labeled analogue of 3-Bromobenzoic Acid Methyl Ester (B680250), an halogenated benzoate derivative used as a reagent in organic synthesis. 3-Bromobenzoic Acid Methyl Ester is used in the synthesis of a novel series of tetrahydrodibenzazocine as inhibitors of 17β-hydroxysteroid dehydrogenase type 3.