反应详情

温度

-78 °C

3,4,5-Trimethoxybenzyl 4-hydroxyphenyl thioether (3g, 9.8 mmol) prepared as described in Example 1 was dissolved in 60 ml of dry methylene chloride, and cooled to -78° C. Then 2.8 ml (29.5 mmol) of borontribromide in 10 ml of methylene chloride was added dropwise to the above solution. After stirring for 2 hr, the solution was warmed to room temperature, and stirred for another 2 hr (monitored by TLC). Then, the reaction mixture was cooled to 0° C., and added dropwise 50 ml of water. The methylene chloride layer was separated. The crude product, obtained after drying over magnesium sulfate and concentration, was purified on silica gel column chromatography (ethyl acetate/n-hexane=2:1). 3,4-Dihydroxy-5-methoxybenzyl 4-hydroxyphenyl thioether (2.1 g, 77% yield) was obtained as a light yellow solid.

1. temperaturethe solution was warmed to room temperature
2. stirringstirred for another 2 hr (monitored by TLC)
3. temperatureThen, the reaction mixture was cooled to 0° C.
4. customThe methylene chloride layer was separated
5. customThe crude product, obtained
6. dry with materialafter drying over magnesium sulfate and concentration
7. customwas purified on silica gel column chromatography (ethyl acetate/n-hexane=2:1)