Hydrochloric Acid → 1-benzyl-1H-pyrazol-4-ol

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Reaction Conditions

Reaction Steps

1-Benzyl-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (Aldrich, 700 mg, 2.46 mmol) was dissolved in THF (6 mL) and cooled to 0° C. NaOH 2.5 M (2 mL, 4.93 mmol) and H2O2 30% solution in water (503 μl, 4.93 mmol) were added and the reaction mixture was stirred at room temperature for 45 min. Then the pH was adjusted to 2 by the addition of aqueous HCl 2 M and the mixture was extracted with dichloromethane. The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel using cyclohexane/EtOAc as eluant. The expected fractions were combined and evaporated under reduced pressure to give the title compound 1-benzyl-1H-pyrazol-4-ol (500 mg, quantitative yield). LCMS: (M+H)+=175; Rt=0.61 min.

Provenance & Evidence