反应详情

温度

-78 °C

Into a solution of 6-bromo-3-(4-methylphenyl)-2H-1-benzopyran (0.5 g) in THF (15 ml) was added at −78° C. 1.6 M butyl lithium (a hexane solution) (1.14 ml) under a nitrogen atmosphere. The resulting mixture was stirred at −78° C. for one hour, was then mixed with dry ice and was stirred for additional one hour. After addition of 1 N hydrochloric acid (10 ml), the resulting mixture was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated solution of sodium chloride and was dried with magnesium sulfate. After concentration under reduced pressure, the resulting crystals were collected by filtration, and the crystals were washed with diethyl ether and hexane to obtain 3-(4-methylphenyl)-2H-1-benzopyran-6-carboxylic acid (218 mg) as colorless crystals.

1. stirringwas stirred for additional one hour
2. extractionthe resulting mixture was extracted with ethyl acetate
3. washThe organic layer was washed with an aqueous saturated solution of sodium chloride
4. dry with materialwas dried with magnesium sulfate
5. concentrationAfter concentration under reduced pressure
6. filtrationthe resulting crystals were collected by filtration
7. washthe crystals were washed with diethyl ether and hexane