反应详情

Under a nitrogen stream, to a solution of 1-(4-bromophenyl)-1H-pyrazole (995 mg, 4.46 mmol) in anhydrous THF (12 ml), a hexane solution of n-butyllithium (1.6 M, 2.79 ml, 4.46 mmol) was added dropwise at −78° C. After stirring at the same temperature for 1 hour, this solution was added dropwise at −78° C. to a solution of trimethyl borate (1.07 ml, 9.37 mmol) in anhydrous THF (8 ml). After stirring at the same temperature for 1 hour, the reaction mixture was stirred at room temperature for one day and a night. After addition of saturated aqueous ammonium chloride, the reaction mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over magnesium sulfate. After filtration, the solvent was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography (developing solution=methylene chloride:methanol (50:1)) to give the titled compound (314 mg, 37%).

1. stirringAfter stirring at the same temperature for 1 hour
2. stirringthe reaction mixture was stirred at room temperature for one day and a night
3. extractionthe reaction mixture was extracted with ethyl acetate
4. washThe organic layer was washed with saturated aqueous sodium chloride
5. dry with materialdried over magnesium sulfate
6. filtrationAfter filtration
7. concentrationthe solvent was concentrated under reduced pressure
8. customThe resulting residue was purified by flash column chromatography (developing solution=methylene chloride:methanol (50:1))