反应详情

A solution of 2-chloro-3-nitropyrazine (1.59 g, 10 mmol) in chloroform (20 ml) was added over 30 minutes to an icebath cooled solution of 4-(2-hydroxyethyl)piperazin-3-one (1.44 g, 10 mmol) and triethylamine (1.01 g, 10 mmol) in isopropanol (30 ml). After addition was complete, the reaction mixture was allowed to warm to 20°-25° and was stirred at this temperature for 20 hours. Solvents were removed under reduced pressure and the residue was partitioned between a saturated aqueous solution of sodium chloride and ethyl acetate. The ethyl acetate extract was dried over anhydrous sodium sulfate, filtered and concentrated to an oil. Flash chromatography over silica gel and elution with 5% methanol-95% chloroform gave 0.90 g (48.6%) of 1-(3-nitro-2-pyrazinyl)-4-(2-hydroxyethyl)piperazin- 3-one. An analytical sample, m.p. 117°-120°, was obtained upon recrystallization from ethyl acetatehexane.

1. additionAfter addition
2. temperatureto warm to 20°-25°
3. customSolvents were removed under reduced pressure
4. customthe residue was partitioned between a saturated aqueous solution of sodium chloride and ethyl acetate
5. extractionThe ethyl acetate extract
6. dry with materialwas dried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated to an oil
9. washFlash chromatography over silica gel and elution with 5% methanol-95% chloroform