An efficient route to the synthesis of novel zwitterionic pyridinium-cyanopropenides with 3-heteroaryl-substituted trimethinium salts.

In this study, eight new zwitterionic derivatives were synthesized using a simple design method from the reaction of various 2-substituted 1,3-bis(dimethylamino)-trimethinium salts with malononitrile or ethyl 2-cyanoacetate in excellent yields in the presence of triethylamine in ethanol at reflux. The molecular structures of the new compounds were confirmed by IR, UV/vis, mass, H, and C NMR spectra as well as by elemental analyses.