Hydrogen Peroxide → 1-benzyl-1H-pyrazol-4-ol

Temperature

0 °C

Into a 100-mL three neck round-bottom flask, was placed a solution of 1-benzyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (compound 244.1, 3.47 g, 12.2 mmol) in tetrahydrofuran (35 mL). Sodium hydroxide (980 mg, 24.5 mmol) was added and then the mixture was cooled to 0° C. Hydrogen peroxide (2.51 mL, 24.4 mmol) was carefully added drop-wise and the resulting mixture was stirred for 2 h at room temperature. The reaction was carefully quenched with aqueous Na2S2O3(sat.) (20 mL). The aqueous phase was extracted with EtOAc (300 mL) and the combined organic layers were washed with brine (2×150 mL), dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography with ethyl acetate/petroleum ether (1/1) as eluent to furnish the title compound as a white solid (1.64 g, 77%).

1. customThe reaction was carefully quenched with aqueous Na2S2O3(sat.) (20 mL)
2. extractionThe aqueous phase was extracted with EtOAc (300 mL)
3. washthe combined organic layers were washed with brine (2×150 mL)
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by silica gel chromatography with ethyl acetate/petroleum ether (1/1) as eluent

ORD record

ord-df3e2c969f6c44b6a14da3477bc219f2

Source dataset

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09428502B2