反应详情

温度

80 °C

To 0.5M-isopropenyl magnesium bromide/tetrahydrofuran is added trimethyl borate (3.3 ml) and the mixture is stirred under nitrogen atmosphere at room temperature for 30 minutes. To the reaction solution are added 6N-hydrochloric acid and diethylether, and the mixture is separated. The organic layer is washed with a saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give isopropenylboronic acid as a crude product (818 mg). The above crude isopropenyl boronic acid (287 mg) and 2-bromo-6-iodo-3-methoxy-pyridine (800 mg) are dissolved in a mixed solvent of 1,2-dimethoxy-ethane (8 ml) and ethanol (3.2 ml) and thereto are added a 1M-aqueous sodium carbonate solution (6.4 ml) and tetrakis(triphenylphosphine)palladium (240 mg) and the mixture is stirred under nitrogen atmosphere at 80° C. for 5 hours. To the reaction solution are added water and ethyl acetate, and the mixture is separated, and the organic layer is washed with a saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (hexane:ethyl acetate=49:1→9:1), followed by NH-silica gel column chromatography (hexane:ethyl acetate=49:1→9:1) to give 2-bromo-6-isopropenyl-3-methoxy-pyridine (138 mg). MS (m/z): 228/230 [M+H]+

1. customthe mixture is separated
2. washthe organic layer is washed with a saturated brine
3. dry with materialdried over magnesium sulfate
4. concentrationconcentrated under reduced pressure
5. customThe residue is purified by silica gel column chromatography (hexane:ethyl acetate=49:1→9:1)