One-Pot Four-Component Synthesis of 5,10-Diarylpyrido[4,3-<italic>b</italic>][1,6] Naphthyridine Derivatives in Ionic Liquids Catalyzed by TsOH.

A one-pot four-component reaction of aldehyde, aromatic amine, and two equivalents of piperidine-2,4-dione was treated in ionic liquids of [BMIm]Br catalyzed by TsOH (<italic>p</italic>-toluenesulfonic acid), and gave a series of 5,10-diarylpyrido[4,3-<italic>b</italic>][1,6]naphthyridine derivatives in good yields. This procedure has the advantages of mild reaction conditions, good yields, one-pot, and environmentally benign. [ABSTRACT FROM AUTHOR]