283173-80-8

1408282-26-7

283173-80-8

8-Fluoro-4,5-dihydro-1H-azabino[5,4,3-cd]indol-6(3H)-one (10 g, 49.0 mmol) was used as a feedstock and suspended in a 1 L reactor at room temperature with 225 mL of a dichloromethane/tetrahydrofuran solvent mixture (1:3, v/v). The resulting suspension was cooled to 5 °C with stirring, followed by dropwise addition of a tetrahydrofuran solution of pyridinium tribromide (17.22 g, 53.9 mmol, dissolved in 75 mL of tetrahydrofuran). The reaction temperature was maintained at 5 °C and stirred continuously for 2 h until the reaction was complete. After completion of the reaction, 100 mL of water was added to give a clarified orange solution. The solution was concentrated under reduced pressure until crystals began to precipitate. Next, 750 mL of saturated sodium carbonate solution was added and the mixture was stirred at room temperature for 1 hour to form a suspension. The crystals were collected by filtration, washed with 100 mL of water, and subsequently dried in a vacuum oven at 55 °C for 4 h. 11.3 g of the target product, 2-bromo-8-fluoro-4,5-dihydro-1H-azabino[5,4,3-cd]indol-6(3H)-one, was finally obtained.