反应详情

To a solution of 4,6-difluoro-3-iodo-1H-indazole (2.11 g, 7.53 mmol) in THF (45 mL) at 0° C. was slowly added sodium hydride (60% in mineral oil, 362 mg, 9.04 mmol). The reaction mixture was stirred at room temperature for 10 min then cooled to −10° C. and isopropylmagnesium chloride (2.0 M in THF, 4.52 mL, 9.04 mmol) was added. The reaction mixture was stirred at −10° C. for 30 min then tributylchlorostannane (2.66 mL, 9.8 mmol) was added dropwise. Stirring was continued at −10° C. for 20 min then at room temperature for 3 h. The reaction mixture was quenched with saturated aqueous NH4Cl then diluted with water and extracted with EtOAc (2×). The combined organics were washed with brine then dried over MgSO4 and concentrated. The residue was purified by silica gel chromatography with 10% to 20% EtOAc/heptane (0.5% Et3N) to afford 1.94 g (58%) of 4,6-difluoro-3-tributylstannanyl-1H-indazole as a pale yellow viscous oil. 1H NMR (CDCl3, 300 MHz): δ (ppm) 7.03 (dd, J=8.9, 2.1 Hz, 1H), 6.60 (td, J=9.8, 2.1 Hz, 1H), 1.51-1.64 (m, 6H), 1.29-1.42 (m, 6H), 1.20-1.29 (m, 6H), 0.88 (t, J=7.4 Hz, 9H).

1. customat 0° C.
2. temperaturethen cooled to −10° C.
3. stirringThe reaction mixture was stirred at −10° C. for 30 min
4. stirringStirring
5. waitwas continued at −10° C. for 20 min
6. waitat room temperature for 3 h
7. customThe reaction mixture was quenched with saturated aqueous NH4Cl
8. additionthen diluted with water
9. extractionextracted with EtOAc (2×)
10. washThe combined organics were washed with brine
11. dry with materialthen dried over MgSO4
12. concentrationconcentrated
13. customThe residue was purified by silica gel chromatography with 10% to 20% EtOAc/heptane (0.5% Et3N)