Synthesis of ۲-Amino-۳,۵-dicarbonitrile-۶-thiopyridines Using Silica-bonded N-Propyldiethylenetriamine as a Heterogeneous Solid Base Catalyst

Silica-bonded N-propyldiethylenetriamine (۷) is employed as a recyclable heterogeneous solid base catalyst for the synthesis of ۲-amino-۳,۵-dicarbonitrile-۶-thiopyridines through pseudo four-component condensation reaction between aromatic aldehydes, malononitrile, and ۲-amino-thiophenol in refluxing ethanol. Silica-bonded N-propyldiethylenetriamine showed much the same efficiency when used in consecutive reaction runs.