A. α,α'-Dicyano-β-methylglutaramide. In a 6-l. flask, 520 g. (6.2 moles) of recrystallized cyanoacetamide (Note 1) is dissolved in 3.4 l. of water, and the solution is cooled to 10° and filtered if it is not clear (Note 2). While the flask is shaken constantly, 137.5 g. (3.1 moles) of freshly distilled acetaldehyde and 20 ml. of piperidine are added successively to the solution. After the mixture has stood at room temperature for 2 hours, the flask is transferred to an ice-salt bath and the mixture is partially frozen. During this operation, the flask should be shaken frequently. After 30 minutes, α,α'-dicyano-β-methylglutaramide begins to deposit, and when the precipitation is complete (about 1 hour), the mixture is allowed to come to room temperature in order to melt the ice that is present. The precipitate is then filtered with suction and washed thoroughly with cold distilled water. The yield is 420–425 g. (71%) of a white, powdery solid which melts at 152–157° (Note 3).

B. β-Methylglutaric acid. In a 5-l. flask are placed 400 g. of the amide and 1 l. of concentrated hydrochloric acid; the mixture is warmed on a steam bath until solution is complete, after which it is diluted with 1 l. of water and refluxed for 8 hours. The amber-colored solution is saturated with sodium chloride and extracted with five 600-ml. portions of ether. The combined ether extracts are dried for 1 hour over phosphorus pentoxide, and the solvent is removed by distillation. The residue, crude β-methylglutaric acid, weighs 238–240 g. (80%) and melts at 79–82° with previous softening. This product is recrystallized from about 250 ml. of 10% hydrochloric acid. The recovery is about 90% (Note 4), and the purified product melts at 85–86°.