1753-75-9

1575-37-7

1753-75-9

Example 2 Synthesis of 5-bromo-2,1,3-benzothiadiazole: A reaction mixture was prepared by mixing 4.0 g (21 mmol) of 4-bromophthalimide, 14 mL of thionyl chloride and 0.62 mL of concentrated sulfuric acid. The mixture was heated to reflux for 1 hour. Upon completion of the reaction, the mixture was cooled and subsequently slowly poured into ice water. The precipitate precipitated was collected by filtration and washed with plenty of water until the washings were neutral. Finally, the precipitate was thoroughly dried to give 4.5 g of 5-bromo-2,1,3-benzothiadiazole crude product (melting point 48 to 50 °C, yield 96.5%).