Synthesis of Imidazolinium Salts by Pd/C-Catalyzed Dehydrogenation of Imidazolidines

A method for the synthesis of imidazolinium salts through a catalytic dehydrogenation was developed using Pd/C as a catalyst with ammonium salt as an additive. Optimization of the reaction conditions revealed the existence of a proton source that was necessary to accomplish the reaction. Under the optimal conditions, oxidation-sensitive components, such as an allyl, a furan, and a thiophene can be introduced into the corresponding imidazolinium salts. In addition to the varied N-substituents, the presented method can be used to synthesize a series of 2-substituted imidazolinium salts.