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

Participants

Reaction Conditions

Reaction Steps

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%).

Provenance & Evidence