84-65-1

1143-50-6

General procedure for the synthesis of 5H-dibenzo[b,e]azepine-6,11-dione using anthraquinone as starting material: a mixed solution of concentrated sulfuric acid (25.2 mL) and dichloromethane (DCM) (8.4 mL) was cooled to 0 °C, followed by the addition of anthraquinone (1) (5 g, 24 mmol). Sodium azide (1.84 g, 28.3 mmol) was added in small batches at 0-5 °C, taking about 1 hour. The reaction mixture was stirred overnight at room temperature and then slowly poured into ice water (300 mL). The product was collected by filtration, washed with water to neutral to remove residual acid, and dried to afford 5H-dibenzo[b,e]azepine-6,11-dione (2) as a white solid (5.3 g, 100% yield). Mass spectral data: m/z = 224 ([M + H]+).