Ultrasound-promoted N-propargylation of imidazole by alkaline-doped carbons Original Research Article

The synthesis of N-propargyl imidazoles via alkylation of imidazole with propargyl bromide by sonochemical and thermally activated reactions over two alkaline promoted carbons (Na and Cs-Norit) as catalysts is reported. In this green, solvent free procedure, we produce exclusively N-propargyl imidazoles in very high yields (>80%) when the Cs+-Norit carbon is employed under ultrasound activation. The basicity of the alkaline cation increases the conversion and ultrasound activation affords a remarkable increase in the yields. The catalysts were characterized by thermal analyses, X-ray photoelectron spectroscopy and nitrogen adsorption isotherms.