2,5-Dibromonitrobenzene

106-37-6

3460-18-2

The general procedure for the synthesis of 2,5-dibromonitrobenzene from 1,4-dibromobenzene was as follows: a mixture of nitric acid (90%, 4.6 g, 70 mmol) and concentrated sulfuric acid (75 mL) was slowly added dropwise to a solution of dichloromethane (30 mL) and concentrated sulfuric acid (20 mL) containing 1,4-dibromobenzene (11.8 g, 50 mmol), with the use of a dropping funnel during the addition. The acceleration of the drop was controlled and the reaction was carried out at room temperature for 20 min. After completion of the reaction, stirring of the reaction mixture was continued for 30 min. Subsequently, the reaction was quenched with 25% aqueous sodium hydroxide solution (3 mL), the reaction product was extracted with dichloromethane (30 mL) and the aqueous layer was washed with dichloromethane (10 mL). The organic phases were combined and dried over anhydrous magnesium sulfate. The solvent was removed by evaporation under reduced pressure to give the light yellow crystalline product 2,5-dibromonitrobenzene (13.7 g, 97% yield) with a melting point of 83-84°C. The product was extracted by 1H NMR and the aqueous layer was washed with dichloromethane (10 mL). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3), δ 7.98 (d, J = 2.3 Hz, 1H), 7.55-7.63 (m, 2H).