Ruthenium Complex-Controlled Catalytic N-Mono- or N,N-Dialkylation of Heteroaromatic Amines with Alcohols

Yoshihisa Watanabe; Yasuhiro Morisaki; Teruyuki Kondo; Take-aki Mitsudo Ta

doi:10.1021/jo9516289

Ruthenium Complex-Controlled Catalytic N-Mono- or N,N-Dialkylation of Heteroaromatic Amines with Alcohols

J Org Chem. 1996 Jun 26;61(13):4214-4218. doi: 10.1021/jo9516289.

Authors

Yoshihisa Watanabe¹, Yasuhiro Morisaki, Teruyuki Kondo, Take-aki Mitsudo Ta

Affiliation

¹ Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01, Japan.

PMID: 11667318
DOI: 10.1021/jo9516289

Abstract

Heteroaromatic amines were N-alkylated with primary alcohols at 150-200 degrees C in the presence of a catalytic amount of various ruthenium complexes to give the corresponding monoalkylated and dialkylated amines in good to high yields. For example, 2-aminopyridine reacted with an excess of ethanol at 180 degrees C for 20 h in the presence of dichlorotris(triphenylphosphine)ruthenium [RuCl(2)(PPh(3))(3)] to give 2-(ethylamino)pyridine (1) and 2-(diethylamino)pyridine (2) in 9% and 70% yields, respectively. On the other hand, when (eta(4)-1,5-cyclooctadiene)(eta(6)-1,3,5-cyclooctatriene)ruthenium [Ru(cod)(cot)] was used as a catalyst, even in the presence of excess ethanol, 1 was obtained in 85% yield with high selectivity. The addition of tertiary phosphines and phosphites to Ru(cod)(cot) increased the yield of the dialkylated amine.