反应详情

A solution of 394.4 g (0.60 mols; 1.20 eq) of 25% aqueous hydroxylamine sulfate was placed in a 2-liter round-bottom flask equipped with a reflux condenser, thermometer, dropping funnel, mechanical stirrer, and cooling bath. To this was added, over about a thirty minute period, 94.1 g (1.20 mole) of 50% aqueous sodium hydroxide. Phenolphthalein indicator was added and the last of the caustic was added dropwise to the end point (pH of ~9.5). The temperature was kept below 40° C. Then 400 ml of ethanol was added; the sodium sulfate reaction product, which precipitated upon addition of the ethanol, was removed by filtration. Then 172.0 g (1 mole) of diethyl maleate was added to the ethanol-hydroxylamine solution, and the resulting homogeneous solution was stirred for 30 minutes. This latter reaction produced diethyl N-hydroxyaspartate in quantitative yield (>99%).

1. customequipped with a reflux condenser
2. temperaturecooling bath
3. additionthe last of the caustic was added dropwise to the end point (pH of ~9.5)
4. customwas kept below 40° C
5. customprecipitated upon addition of the ethanol
6. customwas removed by filtration
7. customThis latter reaction