Synthesis of Novel Pyrano[2,3-b]pyridines from α,α′-Bis(substituted-benzylidene)cycloalkanones

In this paper, we describe a two-step synthesis of a series of tacrine analogues. In the first step, α,α'-bis(substituted-benzylidene)cycloalkanones are reacted with malononitrile to afford 2-amino-3-cyano-4H-pyrans. The second step involves the conversion of pyrans to pyrano[2,3-b]pyridines with the use of AlCl3 as catalyst.