Bromine → 4-Bromo-2,5-difluoroaniline

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Reaction Steps

To a stirred solution of 100 g of 2,5-difluoroaniline and 1150 mL of AcOH is added over 1.3 hours a solution of 40.2 mL of Br2 in 350 mL of AcOH at a temperature of 15°-20°. The pink suspension is stirred 30 minutes longer and then evaporated in vacuo. The residue is basified with 50% NaOH (ice is added to keep the temperature below 35°). Extraction of the free base with 1 L of CH2Cl2 and washing of the extract with 2×100 mL of H2O, drying with Na2SO4 and evaporation in vacuo gives 157 g (97.5% yield) of 4-bromo-2,5-difluoroaniline, m.p. 73°-75°. The mass spectrum had a M+1 ions at 208,210.

Provenance & Evidence