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

<p>An economical and efficient synthesis of dipyrimido-dihydropyridines and pyrimido[4,5-<i>d</i>]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-<i>d</i>]pyrimidine derivatives with a wide substitution pattern.</p

Diisopropylethylammonium acetate (DIPEAc): An efficient and recyclable catalyst for the rapid synthesis of 5-substituted-1<i>H</i>-tetrazoles

<p>A simple and efficient protocol developed for the synthesis of 5-substituted 1<i>H</i>-tetrazole derivatives through [2+3] cycloaddition reaction between benzonitriles and sodium azide using diisopropylethylammonium acetate as a recyclable reaction medium is described. The reactions proceed well at 80 °C and provide the corresponding tetrazoles in good to excellent yields (up to 94% yield). Developed method has notable advantages, such as simple and mild conditions, easy workup, reusability with consistent catalytic activity, and safer alternative to hazardous, corrosive conventional Lewis acid catalysts.</p