An Efficient Green Approach for the Synthesis of Structurally Diversified Spirooxindoles Using Sulfonic Acid Functionalized Nanoporous Silica (SBA-Pr-SO3H)

One pot multicomponent reaction between isatin, barbituric acid, and 6amino1,3-dimethyl uracil was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBAPrSO3H) and resulted in the formation of spirooxindole dipyrimidines. Spirooxindole unit is found in many natural products and biologically active molecules and 1,4dihydropyridines are an important class of compounds with interesting biological activities such as vasolidator, antitumor, antidiabetic, bronchodilator and antiatherosclerotic activities. Excellent yields and short reaction timesare related to the highefficiency of SBAPrSO3H that the reactions take place easily in its nanopores. Mild reaction conditions and easy workup procedures are other advantages of this green method.