反应详情

温度

0 °C

To a solution of 5,6-dichloro-3-iodo-1H-indazole (820 mg, 2.62 mmol) in THF (8 ml) at 0° C. was added KOt-Bu (412 mg, 3.67 mmol). The reaction mixture was stirred at 0° C. for 30 min then added iodomethane (0.23 ml, 3.67 mmol). Stirred at 0° C. for 30 min then warmed to room temperature and stirred for 1.5 hr. The reaction was quenched with water and extracted with EtOAc (2×). The combined organics were dried over MgSO4 and concentrated. The crude residue was absorbed on silica gel and purified by chromatography with 20% to 30% EtOAc/hexanes to afford 585 mg (68%) of 5,6-dichloro-3-iodo-1-methyl-1H-indazole as a light yellow solid. 1H NMR (CDCl3, 400 MHz): δ (ppm) 7.61 (s, 1H), 7.56 (s, 1H), 4.09 (s, 3H). The minor 5,6-dichloro-3-iodo-2-methyl-1H-indazole regioisomer was also observed but not isolated.

1. stirringStirred at 0° C. for 30 min
2. temperaturethen warmed to room temperature
3. stirringstirred for 1.5 hr
4. customThe reaction was quenched with water
5. extractionextracted with EtOAc (2×)
6. dry with materialThe combined organics were dried over MgSO4
7. concentrationconcentrated
8. customThe crude residue was absorbed on silica gel
9. custompurified by chromatography with 20% to 30% EtOAc/hexanes