One-Step Synthesis of Imidazolo-Heteroarenes from Heteroarene N-Oxides

Significance

A one-step procedure for the introduction of an imidazole unit into unsubstituted, mono-, and disubstituted heteroarene N-oxides is described. Thus treatment of various pyridine, quinoline, isoquinoline, pyrimidine N-oxides with sulfuryl diimidazole at elevated temperatures leads to the corresponding α-imidazoloheteroarenes in fair to excellent yields. Electron-rich N-oxides led to optimum yields under mild conditions, whereas electron-poor, sterically encumbered substrates required longer reaction times and higher temperatures. A mechanism is proposed.