Diisopropylethylamine → (3S)-ethyl 1-(2-hydroxy-2-(4-(5-(5-isobutyl-4-(trifluoromethyl)isoxazol-3-yl)-1,2,4-oxadiazol-3-yl)phenyl)ethyl)piperidine-3-carboxylate

Participants

Reaction Steps

A mixture of 5-isobutyl-4-(trifluoromethyl)isoxazole-3-carbonyl fluoride; Int-V-D (0.045 g, 0.188 mmol), (3S)-ethyl 1-(2-hydroxy-2-(4-((Z)—N′-hydroxycarbamimidoyl)phenyl)ethyl)piperidine-3-carboxylate (0.063 g, 0.188 mmol), and DIEA (0.043 mL, 0.245 mmol) in acetonitrile (1 mL) was stirred at room temperature for 4 days. The reaction was complete by HPLC. The reaction mixture was diluted with dichloromethane, washed with a saturated aqueous solution of sodium bicarbonate, dried over anhydrous sodium sulfate, and concentrated. The crude reaction mixture was purified by flash silica gel chromatography using a 20% mixture of ethyl acetate in hexane to give (3S)-ethyl 1-(2-hydroxy-2-(4-(5-(5-isobutyl-4-(trifluoromethyl)isoxazol-3-yl)-1,2,4-oxadiazol-3-yl)phenyl)ethyl)piperidine-3-carboxylate (0.055 g, 0.103 mmol, 54.5% yield) as a clear, colorless oil. The product was >99% pure by HPLC with a ret. time=2.87 min.-Column: CHROMOLITH® SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=537.2.

Provenance & Evidence