Hydrazine hydrate (1:1) → 3-(difluoromethyl)-1H-pyrazol-5-amine

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Reaction Steps

To a solution of 4,4-difluoro-3-oxobutanenitrile in EtOH (200 mL) was added hydrazine hydrate (30 mL). The reaction was heated at reflux for 12 h before cooling to RT. After evaporation in vacuo, the residue was extracted into DCM. The organic layers were washed with water, brine, dried (MgSO4). After filtration, the solvent was evaporated in vacuo. The crude product was purified by SiO2 chromatography to afford 5-(difluoromethyl)-1H-pyrazol-3-amine (8.0 g, 27% for two steps) as an oil: MS (ESI) m/z: 134.0 [M+1]+.

Provenance & Evidence