3-Bromo-1,3,4,5-tetrahydro-2H-benzo[b]azepin-2-one

4424-80-0

86499-96-9

General procedure for the synthesis of 3-bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one from 1,3,4,5-tetrahydro-2H-1-benzazepin-2-one: 1,3,4,5-tetrahydro-2H-1-benzazepin-2-one (1.0 g, 6.20 mmol) was dissolved in anhydrous CHCl3 (15 ml) and cooled to 0 °C ( ice-salt bath). Under argon protection, PCl5 (1.5 g, 7.20 mmol) and I2 (15 mg) were added and stirred at 0 °C for 30 min. Subsequently, Br2 (0.39 ml, 7.51 mmol) was added dropwise to the reaction solution, which was slowly warmed to room temperature and refluxed for 4.0 h under argon protection. After completion of the reaction, the mixture was poured into ice water (20 g) and the organic and aqueous phases were separated after thorough stirring. The aqueous phase was extracted with CHCl3 (25 ml), the organic phases were combined, washed with H2O (5.0 ml), dried over anhydrous MgSO4, filtered and concentrated to dryness, and dried under vacuum to give the crude product. The crude product was purified by silica gel column chromatography (Merck, 70 g) with EtOAc: hexane (1:9) as eluent to afford 3-bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one as an off-white solid (1.137 g, 70.1% yield, melting point 170-172 °C). The structure of the product was confirmed by 1H-NMR and 13C-NMR. TLC detection: Rf 0.13 (silica gel plate, EtOAc:hexane=1:4, observed under UV light).