3,4-Dibromobenzoic acid is a colorless crystal at room temperature with a boiling point of 276°C. It is widely used as a pharmaceutical intermediate and, in polymer molding and processing, as a specialty plasticizer added to polymer resins to provide flexibility and toughness.
Toluene was denitrified to take the para product and reduced with Fe/HCl to give p-aminotoluene, this was directly brominated to give 1-amino-2,5-dibromo-4-methylbenzene, which was then reacted with NaNO2/HCl Reaction with NaNO2/HCl gave a diazonium salt, then reduction with H2PO3 gave 3,4-dibromotoluene, and finally oxidation with potassium permanganate gave 3,4-dibromobenzoic acid.
