• Domino ring-opening redox amidation Knoevenagel condensation
• Intramolecular stereoselective protonation
• Grignard allylic substitution
• Acylation of alcohols
• Umpolung reactions

51-17-2

74-88-4

7181-87-5

The general procedure for the synthesis of 1,3-dimethyl-1H-benzo[d]imidazol-3-ium iodide from benzimidazole and iodomethane was as follows: 1H-benzo[d]imidazole (1 g, 8.5 mmol), K2CO3 (1.18 g, 8.5 mmol), iodomethane (2.1 mL, 33 mmol), and acetonitrile (15 mL) were added sequentially to a 25 mL Schlenk tube. The reaction tube was sealed, evacuated and filled with nitrogen three times to displace the air. The mixture was placed in a preheated 83°C oil bath, stirred and heated for 18 hours. Upon completion of the reaction, the reaction mixture was rapidly filtered while hot to remove insoluble material (immediate precipitation of white product was observed). The filtrate was quickly transferred to an ice water bath for cooling to induce the precipitation of white crystals. The crystals were collected by filtration, washed with petroleum ether (PE) and finally dried under reduced pressure to afford the target compound 1,3-dimethyl-1H-benzo[d]imidazol-3-ium iodide (NHC precursor J, 1.3 g, 56% yield).