Efficient sonochemical protocol for the facile synthesis of dipyrimido-dihydropyridine and pyrimido[4,5-d]pyrimidines in aqueous β-cyclodextrin

An economical and efficient synthesis of dipyrimido-dihydropyridines and pyrimido[4,5-d]pyrimidines is described using greener and recyclable β-cyclodextrin as a supramolecular catalyst in aqueous medium. The remarkable features of this method are mild reaction conditions, short reaction times, easy workup procedure, recyclability of the catalyst, and excellent yields of the products. The highly functional group tolerance and shorter reaction times make this method suitable for the synthesis of dihydropyridine and pyrimido[4,5-d]pyrimidine derivatives with a wide substitution pattern.