In a
2-l. Erlenmeyer flask fitted with a reflux condenser and arranged for magnetic stirring are placed
400 ml. of absolute ethanol (Note
1) and
11.5 g. (0.5 g. atom) of sodium added in small portions. After the
sodium has reacted (Note
2), the clear solution is cooled to room temperature, and
42.0 g. (0.5 mole) of finely powdered cyanoacetamide (Note
3) is added with stirring over a period of 1 minute. Immediately thereafter
107.6 g. (0.5 mole) of ethyl (1-phenylethylidene)cyanoacetate (
p. 463) is added. After about 20 minutes, the mixture becomes homogeneous and is allowed to stand at room temperature for 2 hours. Water (650 ml.) is added, followed by
100 ml. of concentrated hydrochloric acid in 1 portion. The resulting suspension is stirred thoroughly with a
glass rod and placed in a refrigerator overnight. The product is then filtered by suction. The filter cake is sucked as dry as possible using a
rubber dam, stirred to a paste with a mixture of 150 ml. of water and
50 ml. of 95% ethanol, and sucked dry. This process is repeated using 200 ml. of water, and the product is dried to constant weight in an
oven at 45°. The yield is
114–116 g. (
90–92%) of the dicyanoglutarimide, m.p.
274–278° (dec.) (Note
4).