反应详情

To a 0° C. solution of 1-(2-amino-5-bromo-3-chlorophenyl)ethanone (206 mg, 0.83 mmol) in 50% aqueous solution of concentrated H2SO4 was slowly added NaNO2 (73 mg, 1.0 mmol). The cooling bath was removed following the addition of NaNO2, stirred at room temperature for 1 hour and then recooled to 0° C. before addition of SnCl2.2H2O (573 mg, 2.49 mmol). The mixture was stirred at 0° C. for 1 hour before dilution with water. The solids were collected by vacuum filtration to afford 5-bromo-7-chloro-3-methyl-1H-indazole (130 mg, 64%).

1. customTo a 0° C.
2. customThe cooling bath was removed
3. additionthe addition of NaNO2
4. filtrationThe solids were collected by vacuum filtration