The bifunctional nanostructured molten salt [4,4′-bipyridine]-1,1′-diium tricyanomethanide
has been employed as a highly efficient and powerful catalyst for the preparation
of 2-amino-4H-chromenes. A wide variety of aromatic aldehydes was condensed with malononitrile
and resorcinol, 1-naphthol or 2-naphthol under mild and solvent-free conditions. This
protocol has the advantages of short reaction times, high to excellent yields, and
straightforward workup.
Key words
multicomponent reactions - molten salt - ionic liquids - solvent-free conditions