反应详情

Tert-butyl 3-(trifluoromethyl)-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-7-carboxylate 11a (370 mg, 1.27 mmol) was dissolved in 30 mL of tetrahydrofuran, followed by addition of N-bromosuccinimide (453 mg, 2.54 mmol) under −78° C. After stirring for 1 hour, the reaction mixture was heated to room temperature and reacted for 12 hours. The reaction mixture was added with 50 mL of H2O, extracted with ethyl acetate (60 mL×3). The organic phase was combined, washed with saturated sodium chloride solution (40 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to obtain crude tert-butyl 1-bromo-3-(trifluoromethyl)-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-7-carboxylate 11b (510 mg) as a light yellow oil. The product was used directly in the next reaction without purification.

1. customreacted for 12 hours
2. extractionextracted with ethyl acetate (60 mL×3)
3. washwashed with saturated sodium chloride solution (40 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under reduced pressure