49764-63-8

88617-67-8

49764-63-8

The general procedure for the synthesis of 4,5-dibromo-o-phenylenediamine using N,N'-(4,5-dibromo-1,2-phenylene)bis(4-methylbenzenesulfonamide) as starting material was as follows: 70 mL of concentrated sulfuric acid was mixed with 35.2 g (0.058 mol) of N,N'-(4,5-dibromo-1,2-phenylene)bis(4-methylbenzenesulfonamide), and the reaction was heated to 110 °C and maintained for for 15 minutes. After completion of the reaction, the mixture was cooled to room temperature, slowly poured into ice water and neutralized with 50% aqueous sodium hydroxide. Subsequently, the precipitate precipitated was filtered, washed thoroughly with 300 mL of water, and dried to give 14.3 g (91% yield) of 4,5-dibromophthalimide, which was analyzed by HPLC to have a purity (area percent) of 97%.