Sulfur Dioxide → 4-broMo-2-cyanobenzene-1-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-amino-2-bromo benzonitrile (10.0 g, 50.75 mmol) in concentrated hydrogen chloride (25 mL) and acetic acid (25 mL) was added sodium nitrite (3.85 g, 55.82 mmol) in water (12.5 mL). The reaction was stirred at 0° C. for 15 minutes. In a separate flask was prepared a saturated solution of sulfur dioxide in acetic acid (25 mL) at 0° C. Calcium chloride dihydrate (3.46 g, 20.30 mmol) was added to the saturated solution prior to the dropwise addition of the solution containing 5-amino-2-bromo benzonitrile. The reaction mixture was warmed to room temperature and stirred for 16 hours. The reaction mixture was diluted with water and the resulting white precipitate collected by filtration. The solids were dissolved in dichloromethane and washed with a saturated aqueous solution of sodium chloride. The organics were dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The material was purified by column chromatography (5% ethyl acetate in heptane elution). Fractions containing product were combined and concentrated in vacuo to obtain the title compound as a colourless solid.

Provenance & Evidence