THE N,N'-DIACYL-4,5-DIHYDROIMIDAZOLIUM ION AS AN ELECTROPHILE
2-Methyl-4,5-dihydroimidazole/acetic anhydride reacts smoothly with indole at room temperature giving N,N'-diacetyl-2-methyl-2-(3-indolyl)-imidazolidine.This adduct can be hydrolysed to 3-acetylindole.Other aromatics, like 1,3-dimethoxybenzene, undergo similar reactions.