Acetic Acid → Acetamidomalonic acid diethyl ester

Participants

Reaction Conditions

Reaction Steps

0.67 mol of acetic acid is fed into a mixture made from 0.38 mol of diethyl malonate, 1.14 mol of acetic anhydride and 0.5 mol of sodium nitrite, with stirring, at a temperature of 40° C., in such a way as to prevent the reaction temperature from exceeding 50° C. (metering time: about 3 hours). Stirring is continued for 4 hours at 50° C., followed by cooling to room temperature. Salts derived from the reaction are filtered off, and the salt is then washed with about 100 ml of methyl tert-butyl ether. The sodium acetate from the post precipitation is filtered off, and the mother liquor is mixed with 5 g of platinum/carbon (5%). The mixture is hydrogenated at a hydrogen pressure of 5 bar and a temperature of from 45 to 50° C.Hydrogen uptake ceases after about 4 hours. The mixture is cooled and the pressure released, and some of the solvent is removed by distillation in vacuo. After crystallization of the product the solid is isolated by filtration. This gives a yield of 85% of diethyl acetylaminomalonate.

Provenance & Evidence