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), dimethylamine hydrochloride (156 mg, 2 mmol) and N,N-diisopropylethylamine (387 mg, 3 mmol). After stirring for 12 hours, the reaction mixture was concentrated under reduced pressure, added with 50 mL of ethyl acetate, and washed successively with saturated ammonium chloride solution (30 mL) and saturated sodium chloride solution (20 mL×3). The organic phase was combined, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to obtain crude tert-butyl 1-(dimethylcarbamoyl)-3-(trifluoromethyl)-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-7-carboxylate 22a (362 mg) as a light yellow solid. 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 solution (30 mL) and saturated sodium chloride solution (20 mL×3)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under reduced pressure