773887-09-5

773887-07-3

773887-09-5

4-Bromo-2-isopropyl-6-methylaniline (1.1 g, 4.8 mmol) was used as starting material and dissolved in 15 mL of acetic acid. Under stirring conditions, 2 mL of aqueous sodium nitrite (400 mg, 5.8 mmol) was slowly added. The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the reaction solution was concentrated under reduced pressure. Saturated sodium bicarbonate solution was added to the concentrate to neutralize the reaction solution. Extraction was performed with ethyl acetate (20 mL x 3) and the organic phases were combined. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to give the crude product. The crude product was purified using a CombiFlash rapid preparative chromatography system with eluent system B as the mobile phase. The target compound 5-bromo-7-(1-methylethyl)-1H-indazole (670 mg, yield: 58.1%) was finally obtained.