Use of sodium bromate for aromatic bromination: Research and development

Sodium bromate is a powerful brominating agent for aromatic compounds that contain deactivating substituents. A bromination process, in which sodium bromate was utilized, was, optimized on laboratory scale, Addition of a strong acid into a stirred aqueous solution, or slurry, of the substrate and bromate salt at 40-100 degrees C, leads to the decomposition of the bromate ions and production of the active brominating species. Substrates such as nitrobenzene, benzoic acid, and benzaldehyde were brominated in high yields (85-98%) and specificity, The reaction is especially useful for the bromination of disubstituted benzenes, such as 4-nitrofluorobenzene or 4-fluorobenzoic acid. Several substrates, such as dinitrobenzenes or nitrobenzoic acids, did not undergo bromination at all, The main parameters of the reaction and some of its synthetic potential are discussed.