Org. Synth. 1963, 43, 25
α-(N,N-DIMETHYLAMINO)PHENYLACETONITRILE
[Glycinonitrile, N,N-dimethyl-2-phenyl-]
Submitted by Harold M. Taylor and Charles R. Hauser
1.
Checked by W. Bruce Kover and John D. Roberts.
1. Procedure
A mixture of 1.5 l. of water and 624 g. (6.00 moles) of sodium bisulfite in a 5-l. beaker equipped with a mechanical stirrer is stirred until solution is complete. Benzaldehyde (Note 1) (636 g., 6.00 moles) is added and the mixture is stirred for 20 minutes, during which time a slurry of the benzaldehyde-bisulfite addition product is formed. A 25% aqueous solution of dimethylamine (1100 g.) containing 275 g. (6.13 moles) of the amine is run in, and stirring is continued as most of the addition compound dissolves. The beaker is immersed in an ice bath, and 294 g. (6.00 moles) of sodium cyanide (Caution! Toxic) is added over a period of 20–25 minutes.
The ice bath is removed after addition of the sodium cyanide, and the mixture is stirred for 4 hours. The organic layer is separated, and the aqueous layer is extracted with three 500-ml. portions of ether. The combined ethereal extracts and organic layer are washed with two 100-ml. portions of cold water and dried over anhydrous magnesium sulfate. The ethereal solution is filtered, and the ether is removed at atmospheric pressure. The residue is transferred to a vacuum distillation system and distilled under reduced pressure (Caution! See (Note 2)). The yield of α-(N,N-dimethylamino)phenylacetonitrile boiling at 88–90°/1.9–2.1 mm. is 842–844 g. (87–88%) (Note 3) and (Note 4).
2. Notes
1.
Eastman Kodak benzaldehyde (white label grade) was used without further purification.
2.
Occasionally the odor of
hydrogen cyanide can be detected during the distillation, even when a
trap filled with
sodium hydroxide pellets precedes the usual trap cooled in dry ice and
acetone to protect the pump. For safety, the
vacuum pump should be placed in a
hood, or provision should be made for the pump exhaust to be vented into a hood or out-of-doors during the distillation.
3.
Anhydrous
dimethylamine has been used by the submitters in a slightly different procedure to give yields up to 95% of the theory.
4.
The checkers carried out the preparation with one-half of the specified quantities without any decrease in the yield.
3. Discussion
The procedure described above is a modification of that of Hauser, Taylor, and Ledford
2 and of Luten
3 which avoids use of anhydrous
dimethylamine. It is related to the procedure of Goodson and Christopher
4 that employs
benzaldehyde, aqueous
dimethylamine hydrochloride, and
potassium cyanide.
The product can also be prepared from
benzaldehyde,
dimethylamine, and
potassium cyanide in cold
acetic acid and aqueous
ethanol.
54. Merits of the Preparation
The method can be used to prepare a number of α-aminonitriles from aliphatic or aromatic aldehydes and ketones and secondary aliphatic amines.
6The nitrile group of
α-(N,N-dimethylamino)phenylacetonitrile can generally be replaced by an alkyl or aryl group of a Grignard reagent to form the corresponding tertiary amines.
4,7 The α-hydrogen of the aminonitrile can be alkylated,
2,7 and the resulting alkylation product can be converted to enamines
2 or to ketones.
7
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ethanol (64-17-5)
acetic acid (64-19-7)
ether (60-29-7)
sodium hydroxide (1310-73-2)
sodium cyanide (143-33-9)
hydrogen cyanide (74-90-8)
potassium cyanide (151-50-8)
sodium bisulfite (7631-90-5)
benzaldehyde (100-52-7)
acetone (67-64-1)
dimethylamine (124-40-3)
dimethylamine hydrochloride (506-59-2)
magnesium sulfate (7487-88-9)
Glycinonitrile, N,N-dimethyl-2-phenyl-,
α-(N,N-DIMETHYLAMINO)PHENYLACETONITRILE (30123-97-8)
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