反应详情

(R)-[3-Oxo-1-(2,4,5-trifluoro-benzyl)-3-(3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl)-propyl]-carbamic acid tert-butyl ester 1l (20.0 g, 39.6 mmol) was dissolved in 300 mL of anhydrous ethanol under stirring, and 1-bromo-2,5-pyrrolidinedione (14.1 g, 79.2 mmol) was then added to the solution at room temperature. After stirring for an hour, potassium carbonate (10.9 g, 79.2 mmol) and di-tert-butyl dicarbonate (8.6 g, 39.6 mmol) were added to the mixture, and the mixture was stirred for an hour and monitored by thin layer chromatography until the disappearance of the starting materials. The reaction mixture was filtered through a pad of coarse silica gel to remove potassium carbonate, and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound (R)-[3-oxo-1-(2,4,5-trifluoro-benzyl)-3-(1-bromo-3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl)-propyl]-carbamic acid tert-butyl ester 1m (20.0 g, yield 86%) as a white solid.

1. stirringAfter stirring for an hour
2. stirringthe mixture was stirred for an hour
3. filtrationThe reaction mixture was filtered through a pad of coarse silica gel
4. customto remove potassium carbonate
5. concentrationconcentrated under reduced pressure
6. customThe resulting residue was purified by silica gel column chromatography