Synthesis and in vitro microbiological evaluation of novel series of 8-hydroxy-2-(2-oxo-2H-chromen-3-yl)-5-phenyl-3H-chromeno [2,3-d]pyrimidin-4(5H)-one derivatives catalyzed by reusable silica-bonded N-propylpiperazine sulfamic acid

Ball milling for the quantitative and specific solvent-free Knoevenagel condensation + Michael addition cascade in the synthesis of various 2-amino-4-aryl-3-cyano-4H-chromenes without heating

Various 2-amino-4-aryl-3-cyano-4H-chromenes have been quantitatively prepared by dry ball milling in the presence of catalytic Na₂CO₃. The orientation specificities are discussed; existing misattributions are pointed out and clarified by NMR.