反应详情

7-Tert-butoxycarbonyl-3-(trifluoromethyl)-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-1-carboxylic acid 20a (330 mg, 1 mmol) was dissolved in 5 mL of N, N-dimethylformamide, followed by addition of O-(1-benzotriazolyl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (756 mg, 2 mmol), cyclopropylmethylamine (142 mg, 2 mmol) and N,N-diisopropylethylamine (0.5 mL, 3 mmol). After stirring for 12 hours, the reaction mixture was concentrated under reduced pressure and added with 50 mL of ethyl acetate and washed successively with saturated ammonium chloride (15 mL×3) and saturated sodium chloride solution (10 mL). The organic phase was collected, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to obtain crude tert-butyl 1-(cyclopropylmethylc arb amoyl)-3-(trifluoromethyl)-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-7-carboxylate 24a (300 mg) as a brown-red oil. The product was used directly in the next reaction without purification.

1. concentrationthe reaction mixture was concentrated under reduced pressure
2. additionadded with 50 mL of ethyl acetate
3. washwashed successively with saturated ammonium chloride (15 mL×3) and saturated sodium chloride solution (10 mL)
4. customThe organic phase was collected
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationThe filtrate was concentrated under reduced pressure