Efficient synthesis of a novel series of indeno fused pyrido[2,3-d]pyrimidines using β-cyclodextrin-propyl sulfonic acid as an eco-friendly catalyst

A simple and facile synthesis of 5-aryl-5,11-dihydro-1H-indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidine-2,4,6-trione derivatives was accomplished by the one-pot condensation of aromatic aldehydes, 1,3-indandione and 6-amino uracil under solvent-free conditions in the presence of the catalyst, β-cyclodextrin-propyl sulfonic acid (β-CD-PSA). This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity.