Acetone → 4-fluoro-1H-indazol-3-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,6-difluorobenzonitrile (3 g, 21.6 mmol) in anhydrous ethanol (50 mL) was added hydrazine hydrate (4.18 mL, 86 mmol). The reaction was heated at 90° C. under nitrogen for 4 hours. Reaction mixture was cooled to room temperature, treated with acetone (20 mL) and left to stand for 18 hours. The mixture was evaporated in-vacuo to yield an orange/brown solid which was partitioned between saturated aqueous sodium hydrogen carbonate solution and dichloromethane. The organic layer was passed through a hydrophobic frit and evaporated in-vacuo to yield a brown solid (4.58 g), which was absorbed onto Florisil (60-100 mesh), applied to a 100 g silica SPE cartridge and purified on a Flashmaster II using a 0-10% methanol in dichloromethane gradient over 60 min. Fractions 48-57 were combined and the solvent was evaporated in-vacuo to yield the title compound as a brown solid (3.08 g, 94%). LCMS (System B) RT=1.38 min, ES+ve m/z 152 (M+H)+.

Provenance & Evidence