Hydrazine → tert-butyl (S)-1-((R)-2,2,2-trifluoro-1-(6-hydrazinylpyridin-3-yl)ethyl)pyrrolidin-3-ylcarbamate

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Reaction Steps

A solution of tert-butyl (S)-1-((R)-1-(6-chloropyridin-3-yl)-2,2,2-trifluoroethyl)pyrrolidin-3-ylcarbamate (68.5 g, 180.4 mmol) and anhydrous hydrazine (56.61 mL, 1804 mmol) in i-BuOH (80 mL) was stirred at 106° C. in a sealed flask for 16 hours. After cooling to ambient temperature, the solvent was removed under reduced pressure. The residue was partitioned in ethyl acetate (800 mL) and water (100 mL). The organic layer was separated, washed with brine, dried (sodium sulfate), filtered and concentrated under reduced pressure to give tert-butyl (S)-1-((R)-2,2,2-trifluoro-1-(6-hydrazinylpyridin-3-yl)ethyl)pyrrolidin-3-ylcarbamate (68.1 g, 95.6%) as white foam solid. Enantiomeric excess was determined by chiral HPLC (Chiralcel OD-H, 90% hexane/10% (1:1 MeOH/EtOH) at 1.0 mL/min, >99% d.e. (R,S)-diastereomer).

Provenance & Evidence