Tributyltin Chloride → 5-methoxy-1-methyl-3-(tributylstannyl)-1H-indazole

Temperature

-16 °C

3-iodo-5-methoxy-1-methyl-1H-indazole (0.355 g, 1.23 mmol) was dissolved in THF (3.00 mL). The yellow solution was cooled to −16° C. (NaCl/ice bath), isopropylmagnesium chloride 2M in THF (690 μL, 1.38 mmol.12) was added dropwise at −16° C. The reaction mixture was stirred at −16° C. for 20 min where a solid precipitated. Then, tributylchlorostannane (461 mg, 384 μL, 1.42 mmol.15) was added slowly. The reaction mixture was warmed to 25° C. and stirred for 1.5 h. The reaction mixture was quenched with saturated ammonium chloride solution, extracted with dichloromethane (3×30 mL), organics dried over MgSO4 and concentrated to a yellow oil. The residue was dried under high vacuum to give crude 5-methoxy-1-methyl-3-(tributylstannyl)-1H-indazole, which was used directly in the next step without further purification. The crude mass exceeded the expected amount so the yield was assumed to be quantitative.

1. additionwas added dropwise at −16° C
2. customprecipitated
3. temperatureThe reaction mixture was warmed to 25° C.
4. stirringstirred for 1.5 h
5. customThe reaction mixture was quenched with saturated ammonium chloride solution
6. extractionextracted with dichloromethane (3×30 mL)
7. dry with materialorganics dried over MgSO4
8. concentrationconcentrated to a yellow oil
9. customThe residue was dried under high vacuum

ORD record

ord-34a2397e498445f197bca3a3581d81c8

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08658646B2