Stability and decarbonylation of 1,3-dialkyl-2-formylimidazolium perchlorate in solution

The stability of 1,3-dialkyl-2-formylimidazolium perchlorate 1 in solution was studied in detail and found to be related to its structure and the solvent character and temperature. 1 was stable in common solvents at room temperature and unstable in protic solvents under reflux. In protic solvents, such as H₂O, MeOH, EtOH, and AcOH, 1 decarbonylated into 1,3-dialkylimidazole perchlorates 2, which was confirmed by ¹H NMR, ¹³C NMR, HRMS, and X-ray spectroscopy. The decarbonylation of 1 was proposed to occur via its hemiacetal formed by the addition of solvents based on the tracking NMR spectra of 1 in deuterated reagents. (author)