C–N Bond Formation by the Oxidative Alkylamination of Azines: Comparison of AgPy2MnO4 versus KMnO4 as Oxidant

Reports on the successful oxidative alkylamination of azines by the SNH‐reaction, with the use of alkylamines other than methylamine, are very scarce. Hitherto, the experimental limitation to extend oxidative amination of azines with NH3/KMnO4 to oxidative alkylamination is solely ascribed to the low solubility of KMnO4 in alkylamines and the increased sensitivity of alkylamines towards oxidation in comparison with ammonia. Our experimental data for the first time prove that there is also a substrate dependence in this type of reaction. 2‐Alkylamino‐5‐nitropyridines and 4‐alkylaminoquinazolines were smoothly obtained by the treatment of 3‐nitropyridine and quinazoline, respectively, with alkylamine/AgPy2MnO4. Although KMnO4 still gives moderate to good results with 3‐nitropyridine, it is completely useless for reactions with quinazoline with the same alkylamines. The use of AgPy2MnO4 was found to give equal or superior results to those of KMnO4 depending on the alkylamine and the substrate used and therefore seems to be a promising general oxidant for successful oxidative alkylaminations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)