One‐pot synthesis of 2‐amino‐4,8‐dihydropyrano[3,2‐b]pyranes and pyridopyrimidines under mild conditions

1,8‐Diazabicyclo[5.4.0]undec‐7‐ene immobilized on silica (SB‐DBU)Cl as a reusable and heterogeneous catalyst was applied for the one‐pot, three‐component synthesis of 2‐amino‐4,8‐dihydropyrano[3,2‐b]pyrane‐3‐carbonitriles and pyridopyrimidines, under solvent‐free conditions. The reaction was carried out at room temperature, and pure products were obtained in high yields and short reaction times (3–7 min). This work introduced an environmentally benign procedure for the synthesis of these classes of biological active compounds.