It is an ester. It is a lachrymator and an important drμg intermediate. Ester group is slightly twisted out of the plane of the central aromatic ring in methyl 4-(bromomethyl)benzoate.It may be used in the synthesis of 9-O-(4-carboxybenzyl)berberine (CBB). It is an ester. It is a lachrymator and an important drug intermediate. Ester group is slightly twisted out of the plane of the central aromatic ring in methyl 4-(bromomethyl)benzoate. It may be used in the synthesis of 9-O-(4-carboxybenzyl)berberine (CBB).