synthesis of novel tetrahydroquinoline derivatives from α,α′-bis(substituted-benzylidene)cycloalkanones

In this paper, we describe a two-step synthesis of a series of substituted tetrahydroquinoline analogies. 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 into 2-amino-5,6,7,8-tetrahydroquinoline-3-carbonitrile derivatives using NH4OAC.