反应详情

To a solution of 7-(2,4-dichloro-phenyl)-2-methyl-2H-indazole (0.659 g, 2.38 mmol) in 2 mL of acetic acid was added bromine (0.122 mL, 2.38 mmol) dropwise. The yellow-orange solution was stirred for 15 m, in which time an orange solid precipitated. The mixture was concentrated to a yellow solid, which was partitioned between 20 mL of a 10% aqueous NaOH solution and 20 mL of diethyl ether. The organic layer was washed with 20 mL of a saturated aqueous NaCl solution, dried over MgSO4, filtered, and concentrated to a yellow-stained white solid. Column chromatography (0→10% EtOAc/hexanes) afforded 3-bromo-7-(2,4-dichloro-phenyl)-2-methyl-2H-indazole as a white solid (24: Ar=2,4-dichlorophenyl; 0.525 g; 62%; m.p. 137-139).

1. customprecipitated
2. concentrationThe mixture was concentrated to a yellow solid, which
3. customwas partitioned between 20 mL of a 10% aqueous NaOH solution and 20 mL of diethyl ether
4. washThe organic layer was washed with 20 mL of a saturated aqueous NaCl solution
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated to a yellow-stained white solid