Serendipitous Formation of a Zwitterionic Imidazolium Molecule from α-Diimine with Glyoxal as Unusual Cyclization Agent

Imidazolium compounds have determined a profound impact on chemistry, and several synthetic methods to access them are well established. Here, we report the serendipitous discovery of the unprecedented route to a zwitterionic imidazolium molecule with the two nitrogen atoms substituted with 4-cyclohexanecarboxylic acid: to build the five-membered ring, glyoxal plays the double role of source for C2 and, unusually, C1 units, the latter via thermal decomposition affording carbon monoxide as side-product. Compound I1 was characterized by elemental analysis, multinuclear NMR, IR and ESI-MS spectroscopy.