A solution of tert-butyl (S)-1-((R)-2,2,2-trifluoro-1-(6-hydrazinylpyridin-3-yl)ethyl)pyrrolidin-3-ylcarbamate (0.15 g, 0.36 mmol) and 6-fluoro-8-(3-methoxypropoxy)quinoline-2-carbaldehyde (0.095 g, 0.36 mmol) in ethanol (1.8 mL, 0.36 mmol) was allowed to stir at ambient temperature for 12 hours. The solvent was removed under reduced pressure. The residue was dissolved in dichloromethane (1.8 mL) and iodosobenzene diacetate (0.13 g, 0.39 mmol) was added. The reaction mixture was stirred at ambient temperature for 1 hour. Ethyl acetate (20 mL) and saturated sodium bicarbonate (10 mL) were added. The organic layer was separated, washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by reverse phase chromatography on a C18 column (0-100% acetonitrile/water) to give the title compound (0.12 g, 55%).
