Heterogeneous Catalyzed Chemoselective Reductive Amination of Halogenated Aromatic Aldehydes

Abstract

The chemoselective conversion of a specific functional group in a multifunctional substrate is of great importance in the chemical industry to obtain cost efficient, sustainable and waste free processes. This work focuses on the chemoselective amination of halogenated aromatic aldehydes with dimethyl amine towards halogenated aromatic amines, a raw material used in the production of for example agrochemical active ingredients. It was found that by combining palladium, a metal known for dehalogenation reactions, and copper, known for its direct hydrogenation of aldehydes to alcohols, in one heterogeneous bimetallic catalyst, a synergistic effect is obtained. By depositing copper onto a palladium on carbon catalyst with a Cu/Pd ratio of at least 1 : 1, the yield could be increased from 66 % (Pd/C) to 98 % (PdCu/C). Moreover, this highly active and stable catalyst also showed suppressed dehalogenation sidereactions in several other chemical conversions such as hydrogenation of nitro functional groups and hydrogenation of aldehydes.

A Career in Catalysis: Laura Prati

“…In the field of aldehydes hydrogenation, one must also mention the work that Laura did on the reductive amination of halogenated aldehydes . The chemoselective conversion of a specific functional group of a substrate is of great importance in the chemical industry, and indeed based on this work, Laura and her co-workers had also successfully filed a patent on the “preparation of compounds containing amino groups bound to a carbon skeleton by reductive alkylation of ammonia, amines or compounds having groups reducible to amino groups, with carbonyl compounds by reduction with hydrogen (ref.…”

Sodium hypophosphite mediated reductive amination of carbonyl compounds with N,N-dialkylformamides

“…1a). [11][12][13][14][15][16][17] However, the use of dimethylamine could be inconvenient due to its gaseous state under standard conditions. The use of dimethylamine hydrochloride requires using a base restricting the reaction applicability.…”