Hydrazine hydrate (1:1) → 1-{[4-Chloro-2-(trifluoromethyl)phenyl]methyl}-1H-pyrazol-3-amine

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Reaction Conditions

Reaction Steps

To a solution of crude 2-(1-{[4-chloro-2-(trifluoromethyl)phenyl]methyl}-1H-pyrazol-3-yl)-1H-isoindole-1,3(2H)-dione (6.14 g, 15.1 mmol) in THF (50 ml) was added hydrazine hydrate (3.67 ml, 76 mmol, Aldrich). The resulting colourless solution was stirred at 50° C. for 1 h. A white solid precipitated. The reaction was cooled down to ambient temperature and filtered through a sinter funnel. The filtrate was then passed through a hydrophobic frit and concentrated under reduced pressure. The sample was pre-absorbed on florosil (15 ml of DCM:MeOH=1:1) and purified on silica 100 g using 0-50% ethyl acetate-dichloromethane. The appropriate fractions were combined and evaporated in vacuo to give the title compound as a white solid (1.57 g); LCMS: (System 3) MH+=276, tRET=0.90 min.

Provenance & Evidence