3-Amino-6-aryl- and 3-amino-6-heteroarylpyridazines have been obtained in generally good yield using a nickel-catalyzed electrochemical cross-coupling between 3-amino-6-chloropyridazines and aryl or heteroaryl halides at room temperature. Comparative experiments involving classical palladium-catalyzed reactions, such as Suzuki, Stille, or Negishi cross-couplings, reveal that the electrochemical method can constitute a reliable alternative tool for biaryl formation. A possible reaction mechanism is proposed on the basis of electrochemical analyses.
Selective mono-amination of dichlorodiazines
作者:Stéphane Sengmany、Julie Lebre、Erwan Le Gall、Eric Léonel
DOI:10.1016/j.tet.2015.05.056
日期:2015.7
A mild, easy-to-perform, and versatile method for the formation of aminochlorodiazines from reaction of several types of dichlorodiazines (i.e., pyridazines, pyrimidines, and pyrazines) with primary or secondary amines in ethanol in the presence of triethylamine as a base, is described. The methodology is general and efficient despite noticeable difference in reactivity between diazines. While dichloropyridazine and dichloropyrazine require several hours of heating at reflux for the reaction to proceed, dichloropyrimidines reach completion within minutes at room temperature. (C) 2015 Elsevier Ltd. All rights reserved.