Tributyltin Chloride → 1-methyl-3-tributylstannanyl-1H-indazole

Temperature

-16 °C

3-Iodo-1-methyl-1H-indazole (0.15 g, 0.58 mmol) was dissolved in THF (3 ml) and the solution was cooled to −16° C. using a NaCl/ice bath. Isopropylmagnesium chloride (2.0M in THF, 0.32 ml, 0.64 mmol) was added dropwise and the reaction mixture was stirred at −16° C. for 15 min. Tributylchlorostannane (0.18 ml, 0.66 mmol) was slowly added and the reaction mixture was allowed to warm to room temperature over 1.5 h. The reaction mixture was quenched with saturated NH4Cl solution and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was purified by chromatography over silica gel with EtOAc/Hexanes (0.5% triethylamine, gradient 0-5% EtOAc) to give 224 mg (92%) of 1-methyl-3-tributylstannanyl-1H-indazole as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ (ppm) 7.70 (d, J=8.3 Hz, 1H), 7.32-7.45 (m, 2H), 7.11 (ddd, J=8.0, 6.3, 1.5 Hz, 1H), 1.52-1.69 (m, 6H), 1.19-1.44 (m, 12H), 0.83-0.95 (m, 9H).

1. temperatureto warm to room temperature over 1.5 h
2. customThe reaction mixture was quenched with saturated NH4Cl solution
3. extractionextracted with EtOAc (2×)
4. washThe combined organic layers were washed with water and brine
5. dry with materialthen dried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified by chromatography over silica gel with EtOAc/Hexanes (0.5% triethylamine, gradient 0-5% EtOAc)

ORD record

ord-2d135379cc97452c9e45c5788a844cf5

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08658646B2