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

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]+.

1. temperatureThe reaction was heated
2. temperatureat reflux for 12 h
3. customAfter evaporation in vacuo
4. extractionthe residue was extracted into DCM
5. washThe organic layers were washed with water, brine
6. dry with materialdried (MgSO4)
7. filtrationAfter filtration
8. customthe solvent was evaporated in vacuo
9. customThe crude product was purified by SiO2 chromatography

ORD record

ord-040566d0ab8845b09d64e43cb6251a96

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08637537B2