91371-12-9

136630-36-9

General procedure for the synthesis of 4,4'-dibromo-2,2'-dinitrobiphenyl-2,2'-diamine from 4,4'-dibromo-2,2'-dinitrobiphenyl: (2) Under nitrogen protection, 4,4'-dibromo-2,2'-dinitrobiphenyl (4.02 g, 10 mmol) was dissolved in a mixture of 48 mL of ethanol and 30 mL of water and tin powder (5.94 g, 50 mmol). The reaction mixture was then heated to 80 °C and maintained at 70 °C for 1 hour. Upon completion of the reaction, the heating was stopped and the reaction flask was cooled in an ice water bath. A 2 mol/L aqueous sodium hydroxide solution was slowly added dropwise until the pH of the reaction system was basic. Then extraction was carried out with dichloromethane, and the organic phases were combined and dried with anhydrous sodium sulfate. The product was purified by silica gel column chromatography using petroleum ether and tetrahydrofuran (20:1, v/v) as eluents. After removal of the solvent under reduced pressure, a light gray solid product was obtained in 85% yield. The structure of the product was confirmed by 1H NMR and confirmed as 4,4'-dibromobiphenyl-2,2'-diamine.