反应详情

To a chloroform (28 mL) solution of 1-(5-methylpyrazin-2-yl)ethanone (1.9 g), under ice cooling in a nitrogen atmosphere, 2,6-lutidine (2.7 mL) and trimethylsilyl trifluoromethanesulfonate (3.0 mL) were added, and the resultant was stirred for 30 minutes. Then, N-bromosuccinimide (3.0 g) was added thereto, and the resultant was stirred at room temperature for 1 hour. Water was added to the reaction solution, and the resultant was stirred for 15 minutes, followed by extraction with chloroform. An organic layer was separated using a phase separator, and the solvent was distilled off under reduced pressure. The obtained residue was purified by silica gel column chromatography (OH-type silica gel; hexane/ethyl acetate-gradient elution=90/10→60/40) and then further purified by hexane/ethyl acetate-gradient elution (=90/10→80/20) to obtain the title compound (2.1 g) as a pale yellow solid.

1. stirringthe resultant was stirred at room temperature for 1 hour
2. stirringthe resultant was stirred for 15 minutes
3. extractionfollowed by extraction with chloroform
4. customAn organic layer was separated
5. distillationthe solvent was distilled off under reduced pressure
6. customThe obtained residue was purified by silica gel column chromatography (OH-type silica gel; hexane/ethyl acetate-gradient elution=90/10→60/40)
7. customfurther purified by hexane/ethyl acetate-gradient elution (=90/10→80/20)