反应详情

温度

10 °C

A solution of ethylmalonic acid diethyl ester (123.6 g) in 95% ethanol (650 ml) is placed in a 1-l four-necked flask fitted with a mechanical stirrer, a condenser, a thermometer and a dropping funnel, and cooled to about 10° C. A solution of NaOH (26.8 g) in water (33 ml) is added dropwise into the above solution over a period of 15 minutes. The mixture is allowed to go to room temperature and stirring is continued for about 1 hour until a neutral pH is reached. By evaporating the solvent under vacuum and heating to about 30°-35° C., a residue is obtained which is taken up with water (400 ml) and extracted with toluene (two 130-ml portions). The toluene extracts are washed with water and the aqueous phase plus the aqueous wash are brought to pH 2 by the addition of 37% HCl (50 ml) and extracted with methylenechloride (four 125-ml portions). The methylene chloride extracts are combined, dried over Na2SO 4 and concentrated to dryness yielding ethylmalonic acid monoethyl ester (87.7 g) as a thick oil.

1. customfitted with a mechanical stirrer, a condenser
2. customto go to room temperature
3. customBy evaporating the solvent under vacuum
4. temperatureheating to about 30°-35° C.
5. customa residue is obtained which
6. extractionextracted with toluene (two 130-ml portions)
7. washThe toluene extracts are washed with water
8. washthe aqueous phase plus the aqueous wash
9. additionare brought to pH 2 by the addition of 37% HCl (50 ml)
10. extractionextracted with methylenechloride (four 125-ml portions)
11. dry with materialdried over Na2SO 4
12. concentrationconcentrated to dryness