反应详情

To a stirred solution of 2-bromo-5H-pyrrolo[2,3-b]pyrazine-7-carboxylic acid (0.527 g, 2.18 mmol) in 50 ml, of methanol was added H2SO4 (1.5 mL) slowly at room temperature. The reaction mixture was stirred at reflux for 16 h. The solvent was evaporated at 40° C. under reduced pressure then the residue was suspended in 5 mL of water and treated with solid NaHCO3 until pH=7. The solution was extracted with ethyl acetate (90 mL), then the organics were washed with water (20 mL), brine (20 mL) and dried over anhydrous sodium sulfate. The drying agent was removed by filtration and the solvent was evaporated at 40° C. under reduced pressure to give a crude product, which was purified by column chromatography (silica gel, 200-300 mesh, eluting with a mixture of petroleum ether and ethyl acetate (1:1, v/v) to give 2-bromo-5H-pyrrolo[2,3-b]pyrazine-7-carboxylic acid methyl ester (0.24 g, 43%) as a white solid.

1. temperatureat reflux for 16 h
2. customThe solvent was evaporated at 40° C. under reduced pressure
3. additiontreated with solid NaHCO3 until pH=7
4. extractionThe solution was extracted with ethyl acetate (90 mL)
5. washthe organics were washed with water (20 mL), brine (20 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. customThe drying agent was removed by filtration
8. customthe solvent was evaporated at 40° C. under reduced pressure
9. customto give a crude product, which
10. customwas purified by column chromatography (silica gel, 200-300 mesh
11. washeluting with a mixture of petroleum ether and ethyl acetate (1:1