反应详情

A mixture of 3-(4-tert-butoxycarbonyl-1-piperazinyl)-2(1H)-pyrazinone (1.20 g, 4.30 mmol; from Example 48, Step 1) and t-BuOK (730 mg, 6.50 mmol) in THF (10 mL) was stirred for 10 min, and then added to a solution of methanesulfonic acid 4-(2,4,5-trifluoro-phenoxy)butyl ester (1.23 g, 4.3 nmol; from Step 2) in THF (50 mL). After being stirred at room temperature for 1 day, HPLC showed about 30% conversion. After 3 days, the reaction was worked up: water was added, THF was evaporated off and the aqueous mixture was extracted twice with EtOAc, dried and concentrated to yield 2.21 g of the crude product as a yellow oil. HPLC analysis showed a 5/1 ratio between the title product and the isomeric O-alkylated product.* Purification by chromatography on silica gel using EtOAc/hexane (1/2 to 1/1) as eluent gave 870 mg (42%) of the title product as a colorless oil. HPLC purity: 95%. MS m/z 483 (M+H)+. *Assignments were based on NMR analysis.

1. stirringAfter being stirred at room temperature for 1 day
2. waitAfter 3 days
3. customTHF was evaporated off
4. extractionthe aqueous mixture was extracted twice with EtOAc
5. customdried
6. concentrationconcentrated
7. customto yield 2.21 g of the crude product as a yellow oil