A Publication of Reliable Methods for the Preparation of Organic
Compounds Annual Volume Org. Synth. 1940, 20, 42 DOI:
10.15227/orgsyn.020.0042 [Hydantoin, 5,5-dimethyl-] Submitted by
E. C. Wagner and Manuel Baizer. Checked by C. F. H. Allen and G.
F. Frame. 1. Procedure In a 600-ml. beaker are mixed 85 g. (1
mole) of acetone cyanohydrin (Note 1) and 150 g. (1.31 moles) of
freshly powdered ammonium carbonate. The mixture is warmed on a
steam bath, preferably in a hood (Note 2), and stirred with a
thermometer (Note 3). Gentle action begins around 50° and
continues during about 3 hours at 68–80°. To complete the
reaction and to decompose excess ammonium carbonate, the
temperature is finally raised to 90° and maintained at this
point until the liquid mixture is quiescent (30 minutes). The
residue is colorless or pale yellow (Note 1) and solidifies on
cooling. It is dissolved in 100 ml. of hot water, digested with
Norit, and filtered rapidly through a heated filter. The
filtrate is evaporated on a hot plate until