866545-96-2

75-36-5

183208-35-7

866545-96-2

Step 1: Synthesis of 1-(5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)ethanone. 5-Bromo-1H-pyrrolo[2,3-b]pyridine (2.00 g, 10.15 mmol) was added to a suspension of aluminum chloride (6.77 g, 50.75 mmol) in stirred anhydrous dichloromethane (100 mL) under nitrogen protection. The reaction mixture was stirred at room temperature for 1 h, followed by slow dropwise addition of acetyl chloride (3.61 mL, 50.75 mmol). After the dropwise addition was completed, the reaction solution was continued to be stirred for 5 hours. Upon completion of the reaction, the mixture was cooled to 0 °C in an ice bath and methanol was added slowly until the solution was clarified to quench the reaction. The reaction solution was concentrated under reduced pressure, water was added and the pH was adjusted dropwise to 4 by addition of 1 N sodium hydroxide solution.The product was extracted with ethyl acetate and the organic layer was washed with saturated potassium sodium tartrate solution to remove residual aluminum salts. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was redissolved in ethyl acetate and filtered through a silica gel bed. The filtrate was concentrated to afford 1-(5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)ethanone as an orange solid (2.25 g, 93% yield).1H NMR (500 MHz, d6-DMSO) δ 12.70 (br s, 1H), 8.56 (d, J = 2.5 Hz, 1H), 8.55 (s, 1H), 8.40 (d , J = 2.5 Hz, 1H), 2.46 (s, 3H). Mass spectrum: m/z 238.9/240.9 (M + H+).