Optimization of the conditions for copper-mediated N-arylation of heteroarylamines

Simple and inexpensive copper-mediated N-arylation of heteroarylamines was achieved by using N,N'-dimethylethylenediamine as a ligand and K2CO3 as a base in dioxane heated at 100 degrees C. In this coupling reaction, the influence of the copper species, ligand, base and solvent was investigated in detail. N-Arylated derivatives of several heteroarylamines were synthesized under optimized reaction conditions, and all the products were isolated in good yields. By controlling the amount of CuI/DMEDA added, heteroarylamines with weak nucleophilic activity were coupled with aryl iodides or aryl bromides. The activity of the copper catalyst for this C-N bond-forming reaction follows the order Cu-I>Cu-0>Cu-II. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.