It is known that nucleophilic aromatic substitution in nitrogen-containing heterocycles by the action of such weak nucleophiles as halide ions is very difficult to occur, even when the heteroring is activated by N-oxide moiety. For example, replacement of nitro group in heteroaromatic N-oxides requires severe conditions: heating with concentrated hydrohalic acids at the boiling boint or using acetyl or phosphinoyl halides [1]. According to the recent ...
