MANNICH REACTIONS OF CARBONYL-COMPOUNDS AND ENAMINES WITH BENZOTRIAZOLE AS THE NH COMPONENT

Boron trifluoride catalyses reactions of 1-(hydroxymethyl)benzotriazole with ketones to give predominantly monosubstituted Mannich products. In unsymmetrical ketones, a methylene is slightly more reactive than a methyl group. For 1,3-diketones and diethyl malonate, substitution occurs on the central methylene group. Beta-Aminocrotononitrile and beta-aminocrotonate undergo Mannich condensations with benzotriazole and formaldehyde without any catalyst. Preliminary investigations of the reactivity of the Mannich bases thus obtained are reported.