Heterogeneously catalyzed selective N-alkylation of aromatic and heteroaromatic amines with alcohols by a supported ruthenium hydroxide

The N-alkylation of aromatic and heteroaromatic amines with alcohols could efficiently be promoted by an easily prepared supported ruthenium hydroxide catalyst Ru(OH)(x)/Al2O3. A variety of aromatic and heteroaromatic amines were selectively converted into the corresponding secondary amines in moderate to excellent yields without any co-catalysts such as bases and stabilizing ligands. The observed catalysis was intrinsically heterogeneous and the Ru(OH)(x)/Al2O3 catalyst recovered after the reaction could be reused without an appreciable loss of its high catalytic performance for the N-alkylation. (C) 2009 Elsevier Inc. All rights reserved.