Tetrahydrofuran → 1,4-dimethyl-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

A solution of 1,4-dimethyl-1H-pyrazole (480.0 mg, 4.993 mol) in tetrahydrofuran (20 mL, 300 mmol) at 0° C. was added 1.6 M n-butyllithium in hexane (4.7 mL, 7.5 mmol). The solution was stirred at room temperature for 1 h and then cooled to −78° C. To the solution was added 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.63 mL, 7.99 mmol). The reaction mixture was stirred at −78° C. for 0.5 h, then warmed up to 0° C. (taking 0.5 h). The reaction was quenched with brine and extracted with EtOAc (3×). The combined organic phases were washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by combi-flash chromatography and eluted with EtOAc/hexane (0-60%). The purification gave 142 mg of product as white solid.

1. temperaturecooled to −78° C
2. stirringThe reaction mixture was stirred at −78° C. for 0.5 h
3. temperaturewarmed up to 0° C. (taking 0.5 h)
4. customThe reaction was quenched with brine
5. extractionextracted with EtOAc (3×)
6. washThe combined organic phases were washed with brine
7. dry with materialdried over Na2SO4
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by combi-flash chromatography
10. washeluted with EtOAc/hexane (0-60%)
11. customThe purification

ORD record

ord-be4ec7e4d77846acb63b7a7447900d42

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08895571B2