We describe a new 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU)-mediated coupling reaction to produce 2-imino benzo[e]-1,3-oxazin-4-ones from salicylic acids and anilines. Mechanistic studies support a reaction pathway in which HATU mediates carbon… Click to show full abstract
We describe a new 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU)-mediated coupling reaction to produce 2-imino benzo[e]-1,3-oxazin-4-ones from salicylic acids and anilines. Mechanistic studies support a reaction pathway in which HATU mediates carbon transfer to the initially formed salicylanilides to form in succession reactive tetramethylisouronium and N-acyl(dimethyl)isouronium intermediates, which then undergo imine–iminium exchange to generate the desired oxazinones.
               
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