反应详情

(R)-tert-Butyl 1-(6-chloro-5-cyanopyrazin-2-yl)piperidin-3-ylcarbamate (87, 550 mg, 1.63 mmol) was dissolved in 20 mL DMF. To it was added NaH (60% in mineral oil, 98 mg, 2.45 mmol). The mixture was stirred at RT for 30 min, and then iodomethane (305 μL, 4.89 mmol) was added. It was stirred for 1.5 hour, diluted with 120 mL EtOAc, washed with water ×3, dried, concentrated, and subjected to flash column using 0 to 50% EtOAc in hexane to isolate (R)-tert-butyl 1-(6-chloro-5-cyanopyrazin-2-yl)piperidin-3-yl(methyl)carbamate (293). It was treated with 20 mL commercial 4N HCl in dioxane at RT for 1 hour, and the mixture was concentrated in vacuo to dryness. It was dissolved in 5 mL DMF and 15 mL dioxane. To it were added DIEA (1.45 mL, 8.15 mmol) and then dimethylcarbamoyl chloride (300 μL, 3.26 mmol). The mixture was stirred at RT for overnight, diluted with 120 mL EtOAc, washed with water ×2, dried, concentrated, and subjected to silica flash column using 0 to 5% MeOH in DCM to isolate (R)-1-(1-(6-chloro-5-cyanopyrazin-2-yl)piperidin-3-yl)-1,3,3-trimethylurea (294, 490 mg, 93% overall) as a white solid.

1. stirringIt was stirred for 1.5 hour
2. washwashed with water ×3
3. customdried
4. concentrationconcentrated