Diisopropylethylamine → tert-butyl (2R,3R)-1-(6-chloro-5-cyanopyrazin-2-yl)-2-methylpiperidin-3-ylcarbamate

Participants

Reaction Steps

tert-Butyl (2R,3R)-2-methylpiperidin-3-ylcarbamate (310) (1.1 g, 5.1 mmol) was dissolved in THF (20 mL). To the stirred solution was added DIEA (1.34 mL, 7.7 mmol), followed by 3,5-dichloropyrazine-2-carbonitrile (1.07 g, 6.2 mmol). The reaction was stirred at room temperature for 1 hour. An additional amount of 3,5-dichloropyrazine-2-carbonitrile (200 mg, 1.2 mmol) was added, and the reaction was stirred for another hour. The solvent was removed under reduced pressure, and the residue was suspended in EtOAc. The organic mixture was washed with 1N HCl (aq), saturated NaHCO3(aq) and brine, dried, and concentrated in vacuo. The residue was then purified by silica flash column chromatography (EtOAc/hexanes) to give tert-butyl (2R,3R)-1-(6-chloro-5-cyanopyrazin-2-yl)-2-methylpiperidin-3-ylcarbamate (311), (1.54 g, 4.38 mmol, 86% yield).

Provenance & Evidence