Hydrogen Peroxide → 2,6-Dibromonitrosobenzene

To a solution of 2,6-dibromoaniline (10 g, 40 mmol) in glacial acetic acid (160 mL) was added 30% hydrogen peroxide (30 mL). The mixture was left for 48 h at which point crystals had precipitated. The crystals were collected by filtration, washed with acetic acid and water then dried under high vacuum to give 2,6-dibromonitrosobenzene (6.24 g). This material (2.6 g, 10 mmol) was dissolved in DMSO (25 mL) along with sodium azide (650 mg, 10 mmol). The mixture was heated to 100° C. for 1 h then cooled to rt and diluted with ethyl acetate and water. The layers were separated and the organic phase was washed with water and brine, then dried over sodium sulfate and concentrated. FC (75 g silica, 10/1 hexane/ethyl acetate) afforded the title compound (1.7 g).