Sulfuric Acid → 5-bromo-1-(4-fluorophenyl)-1H-benzotriazole

Participants

Reaction Steps

To a stirred room temperature solution of 4-bromo-N1-(4-fluorophenyl)benzene-1,2-diamine (1.4 g, 5 mmol) in DMSO (12 mL), was added 30% sulfuric acid (12 mL). The mixture was then cooled (ice-bath) and a solution of sodium nitrite (380 mg, 5.5 mmol) in water (1 mL) was added dropwise. After 20 minutes, a solution of sodium iodide (2.4 g, 15.8 mmol) in water (2 mL) was added dropwise and the cold bath was removed. After 30 minutes, LCMS showed only a single product [MS m/z 292/294 (MH+)] consistent with the desired product. The mixture was poured into 150 mL of ice water and the resulting precipitate was filtered, washed with sodium thiosulfate solution, water and dried to afford 1.3 g of 5-bromo-1-(4-fluorophenyl)-1H-benzotriazole as a light purple solid. MS m/z 292/294 (MH+).

Provenance & Evidence