Revisiting the Minisci Reaction: New Mild Amidoalkylation of Benzo-Fused N-Heteroaromatic Bases under Metal-Free Conditions

In the last few decades, many efforts have been made to make chemical processes more sustainable and reduce their environmental impact. In this context, for the first time, the α-amidoalkylation of benzo-fused N-heteroaromatic bases has been performed in the presence of sodium persulfate as a free-radical source and terminal oxidant without using acids and transition metals. The desired α-amidoalkylated products have been obtained in high yields in relatively short reaction times compared with those generally reported at 50 and 80 °C. The biggest advantage of this new protocol, which does not require acids and metals, is the higher atom economy due to the reduction of the waste. Regarding the reaction mechanism, an interaction between persulfate and the specific amide seems to play a key role in the overall reaction efficiency.