OXIDATIVE CLEAVAGE OF AMINES BY AQUEOUS BROMINE AT 25 DEGREES

Primary, secondary, and tertiary amines are oxidatively cleaved by aqueous bromine at pH 5-7. An alkyl group is removed and the amine with one less alkyl group is produced. Secondary alkyl groups appear as ketones. The fate of primary alkyl groups depends on the type of amine being oxidized. The propyl group appears as propionaldehyde from tripropylamine, as propionic and pyruvic acids from dipropylamine, and exclusively propionic acid from propylamine. All of these results pertain to runs in which the amine is in excess. The selectivity is low between two alkyl groups, and on this basis the mechanism appears to be loss of proton plus an electron pair (Westheimer mechanism) and thus resembles the oxidative cleavage of ethers. However, the data are not conclusive. The oxidation of tertiary amines by triaryl carbonium ions is briefly examined. © 1968, American Chemical Society. All rights reserved.