JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Compounds Containing Nitrogen

Nitrobenzene first undergoes electrophilic bromination with ${\mathrm{Br}}_2/{\mathrm{FeBr}}_3$; the deactivating nitro group directs meta, giving 1-bromo-3-nitrobenzene with one bromine on the ring. Reduction by $\mathrm{Sn}/\mathrm{HCl}$ and neutralisation convert the nitro group to an amino group, giving 3-bromoaniline. Bromine in water then lets the strongly activating amino group direct substitution into all three positions ortho and para to it, adding three more bromines so the ring carries bromine at the 2-, 3-, 4- and 6-positions. Diazotisation with ${\mathrm{NaNO}}_2/\mathrm{HBr}$ at 0-5 degree C followed by the Sandmeyer step with $\mathrm{CuBr}/\mathrm{NaBr}$ replaces the amino group with a fifth bromine. The final product contains 5 bromine atoms.