Synthesis of 1-aminoimidazo[5,1-a]isoquinolinium salts based on multicomponent reactions of isocyanides

A novel pseudo-four-component condensation yielding 1-aminoimidazo[5,1-a]isoquinolinium salts from isocyanides, isoquinoline, and sulfonic or bromic acids is described. The method offers several advantages including high yields of products and an easy experimental workup procedure.