Org. Synth. 1964, 44, 7
DOI: 10.15227/orgsyn.044.0007
N-(2-BROMOALLYL)ETHYLAMINE
[Allylamine, 2-bromo-N-ethyl-]
Submitted by Albert T. Bottini and Robert E. Olsen
1.
Checked by Thomas H. Lowry and E. J. Corey.
1. Procedure
Caution! This preparation should be carried out in a hood to avoid exposure to ethylamine, 2,3-Dibromopropene, and the product. 2,3-Dibromopropene is a strong lachrymator. The operator should wear rubber gloves and protective goggles because some 2-haloallylamines have caused severe skin and eye irritation.
A 1-l. three-necked flask is fitted with a sealed mechanical stirrer, a dropping funnel, and a dry ice condenser charged with an ice-salt mixture (Note 1). Three hundred milliliters (240 g., 3.7 moles) of aqueous 70% ethylamine solution (Note 2) is placed in the flask, the stirrer is started, and 200 g. (1.00 mole) of 2,3-dibromopropene (Note 3) is added dropwise over a period of 1 hour. After the addition is complete, the reaction mixture is stirred for 3 hours. Ether (300 ml.) is added, and the mixture is cooled in an ice bath. Sodium hydroxide (100 g.) is added with stirring and cooling. The cold mixture is transferred to a separatory funnel, and the phases are separated. The organic layer is dried in two stages over 25-g. portions of sodium hydroxide. The organic layer and the small amount of water that separates during the second stage of drying are decanted into a separatory funnel, and the phases are separated. Most of the ether and unreacted ethylamine are removed from the organic layer by distillation through a 250-mm. × 13-mm. column packed with glass helices, and the residue is distilled through the same column at reduced pressure under nitrogen to give 115–128 g. (70–78%) of N-(2-bromoallyl)ethylamine; b.p. 53–55° (27 mm.), 79–81° (75 mm.) (Note 4); n25D 1.4765–1.4770.
2. Notes
1.
The checkers used an inner-spiral water condenser. The cooling water was chilled to about 0° by prior passage through a short
copper coil immersed in ice.
2.
The aqueous
70% ethylamine solution used was the practical grade obtained from Eastman Organic Chemicals.
3.
The
2,3-dibromopropene used was obtained from Columbia Organic Chemicals Co., Columbia, South Carolina, and was redistilled before use. The preparation of
2,3-dibromopropene is described in an earlier volume of this series.
24.
The reported boiling point of
N-(2-bromoallyl)ethylamine is
148–153°.
3 It is strongly recommended that the product and other 2-haloallylamines be distilled at reduced pressure under
nitrogen, for the submitters have noted two instances when a 2-haloallylamine polymerized with considerable evolution of heat during slow distillation at atmospheric pressure.
3. Discussion
This method is essentially that described by Pollard and Parcell.
3 No other procedure appears to have been used to prepare
N-(2-bromoallyl)ethylamine. A number of N-(2-haloallyl)alkylamines have been prepared by treatment of a 2,3-dihalopropene with a primary alkylamine in water,
3,4 ether,
3,4 or
benzene.
54. Merits of the Preparation
The method described here has been used for the preparation of a number of N-(2-haloallyl)alkylamines from a water-soluble amine and the corresponding 2,3-dihalopropene.
3,4Treatment of an N-(2-bromoallyl)alkylamine with
sodium amide in liquid
ammonia yields the N-alkylallenimine together with a small amount of the N-alkylpropargylamine.
3,4,5,6,7 Similar treatment of an N-(2-chloroallyl)alkylamine yields only the N-alkylpropargylamine.
4,6This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ammonia (7664-41-7)
Benzene (71-43-2)
ether (60-29-7)
sodium hydroxide (1310-73-2)
nitrogen (7727-37-9)
copper (7440-50-8)
2,3-Dibromopropene (513-31-5)
sodium amide (7782-92-5)
ethylamine (75-04-7)
N-(2-Bromoallyl)ethylamine,
Allylamine, 2-bromo-N-ethyl- (871-23-8)
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