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

HRID 2174541Notes

Reaction equation

[CH2:1]([N:8]1[CH:12]=[C:11](B2OC(C)(C)C(C)(C)O2)[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[OH-:22].[Na+].OO.O.Cl>C1COCC1>[CH2:1]([N:8]1[CH:12]=[C:11]([OH:22])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 0 °C

Procedure

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.

Workup

extractionthe mixture was extracted with dichloromethane
dry with materialThe organic layer was dried over Na2SO4
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe residue was purified by flash chromatography on silica gel
customevaporated under reduced pressure

Sources & evidence

ORD record: ord-89fbc0e404ff4292bbe306c7ae21769b
Source dataset: uspto-grants-2015_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09061998B2

Reaction notes

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