Synthesis of Functionalized Bicyclic Compounds Based on 2-(1-Arylethylidene)malononitriles

New tetrahydroisoquinoline-5,7-dicarbonitrile derivatives have been synthesized by piperazine hydrate-catalyzed reaction of acetoacetanilide with 2-(1-arylethylidene)malononitriles (Knoevenagel condensation products of acetophenones and malononitrile) in aqueous ethanol at room temperature. The product structure was confirmed by NMR spectra and X-ray analysis of 1,6-diamino-4a-methyl-3-oxo-2,8-diphenyl-2,3,4,4a-tetrahydroisoquinoline-5,7-dicarbonitrile.