ethyl 1-benzyl-1H-pyrazole-4-carboxylate → (1-benzyl-1H-pyrazol-4-yl)methanol

HRID 1363312Notes

Reaction equation

[H-].[Al+3].[Li+].[H-].[H-].[H-].[CH2:7]([N:14]1[CH:18]=[C:17]([C:19](OCC)=[O:20])[CH:16]=[N:15]1)[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1>C1COCC1>[CH2:7]([N:14]1[CH:18]=[C:17]([CH2:19][OH:20])[CH:16]=[N:15]1)[C:8]1[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a stirred suspension of lithium aluminum hydride (LAH) (68 mg, 1.79 mmol) in THF (8 mL) at 0° C. was added dropwise over 5 min a solution of ethyl 1-benzyl-1H-pyrazole-4-carboxylate (250 mg, 1.1 mmol) in THF (5 mL). After stirring for 1 h at 0° C., it was warmed to rt for 30 min and then quenched with 1N HCl until a clear solution was obtained. Extraction with EtOAc (3×50 mL) and washing of the combined organic layers with water, and then brine, provided the crude (1-benzyl-1H-pyrazol-4-yl)methanol after drying and evaporation of the solvent. Crude 1H NMR was clean enough to be used as is without further purification: crude yield 192 mg (94%). 1H NMR (400 MHz, CDCl3) δ ppm 4.58 (s, 2H), 5.29 (s, 2H), 7.21-7.26 (m, 2H), 7.29-7.38 (m, 3H), 7.39 (s, 1H), 7.55 (s, 1H); LCMS-MS (ESI+) 188.90 (M+H).

Workup

temperatureit was warmed to rt for 30 min
customquenched with 1N HCl until a clear solution
customwas obtained
extractionExtraction with EtOAc (3×50 mL)
washwashing of the combined organic layers with water

Sources & evidence

ORD record: ord-8025ff83f956474ca61b2676fe5a99b3
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07884124B2

Reaction notes

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