反应详情

3-(3-Pyridyl)-3-oxopropionic acid ethyl ester (1.95 g, 10.2 mmol) was added dropwise to 47% aqueous HBr solution (3.86 g) under ice-cooling. Bromine (2.2 g, 1.2 equivalent amount relative to 3-(3-pyridyl)-3-oxopropionic acid ethyl ester) was added dropwise at not more than 10° C. After stirring for 30 min, iced-water bath was removed and water (2 ml) and 47% aqueous HBr solution (4 ml) were added. The mixture was stirred at room temperature for 30 min. Furthermore, bromine (2.2 g, 1.2 equivalent amount relative to 3-(3-pyridyl)-3-oxopropionic acid ethyl ester) was added dropwise and the mixture was stirred at 65-70° C. After cooling to room temperature, the reaction mixture was filtrated to give 3.73 g of the titled compound (yield 95.2%).

1. temperaturecooling
2. customiced-water bath was removed
3. additionwater (2 ml) and 47% aqueous HBr solution (4 ml) were added
4. stirringThe mixture was stirred at room temperature for 30 min
5. stirringthe mixture was stirred at 65-70° C
6. filtrationthe reaction mixture was filtrated