反应详情

A solution of 4-bromo-2-ethyl-6-methylbenzenamine (3.21 g, 15 mmol) in acetic acid (50 mL) was stirred for 3 hours before addition of a 2 M solution of sodium nitrite (11 mL, 22.5 mmol). The resulting mixture was stirred overnight at room temperature. The solution was concentrated and the solid was dissolved in EtOAc and washed with saturated aqueous NaCl (3×). The organic extract was dried over Na2SO4, filtered and concentrated. the crude material was purified by Biotage chromatography (40M, 15-30% EtOAc/heptane) to provide 5-bromo-7-ethyl-1H-indazole (1.11 g, 33%) and 5-bromo-3,7-dimethyl-1H-indazole (0.84 g, 25%).

1. concentrationThe solution was concentrated
2. dissolutionthe solid was dissolved in EtOAc
3. washwashed with saturated aqueous NaCl (3×)
4. extractionThe organic extract
5. dry with materialwas dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customthe crude material was purified by Biotage chromatography (40M, 15-30% EtOAc/heptane)