Hydrazine hydrate (1:1) → 3-Tert-butyl-1-(4,4,4-trifluorobutyl)-1h-pyrazol-5-amine

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Reaction Conditions

Reaction Steps

To a solution of Example 135A (5 g, 17.7 mmol) in EtOH (50 mL) was added hydrazine hydrate (1.1 mL, 23.0 mmol). The mixture was warmed to reflux (85° C.) and was allowed to stir for 20 hours. The mixture was cooled to ambient temperature then 4,4-dimethyl-3-oxopentanenitrile (2.9 g, 23.0 mmol) was added and the mixture was again warmed to reflux (85° C.) and stirred for 6 hours. After cooling to ambient temperature, the mixture was concentrated under reduced pressure and the residue was dissolved in CH2Cl2 (100 mL) and saturated aqueous NaHCO3 (50 mL) was added slowly. The layers were separated and the aqueous phase was extracted with CH2Cl2 (3×10 mL). The combined organic extracts were dried over Na2SO4, filtered and concentrated under reduced pressure. Purification by column chromatography (SiO2, 50% hexanes in EtOAc to 100% EtOAc to 9:1:0.1 EtOAc:MeOH:Et3N) afforded the title compound (2.0 g, 8.1 mmol, 46% yield). MS (ESI+) m/z 250 (M+H)+.

Provenance & Evidence