Silica-bonded n-propyltriethylene-tetramine as a recyclable solid base catalyst for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes

Silica-bonded n-propyltriethylene-tetramine (SBNPTT) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes. Chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oC under solvent-free conditions. The heterogeneous solid base showed much the same efficiency when used in consecutive reaction runs.