The general procedure for the synthesis of 2-(4-bromophenyl)-2-oxoacetic acid from the compound (CAS: 58881-56-4) was as follows: selenium dioxide (1.5 mmol) was dissolved in 1,4-dioxane (10.0 mL) and the solution was transferred to a 50 mL round bottom flask. Subsequently, dibenzoyl sulfide derivative 1 (0.5 mmol) was added to the solution and the reaction mixture was heated to reflux for 2 hours. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was filtered to remove insoluble impurities and the solvent was subsequently evaporated under reduced pressure. The crude product was purified by column chromatography using a solvent mixture of petroleum ether and ethyl acetate (90:10, v/v) as eluent to give the final target product 2-(4-bromophenyl)-2-oxoacetic acid.