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 6-amino-1,3-dimethyl uracil was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) and resulted in the formation of spirooxindole dipyrimidines. Spirooxindole unit is found in many natural products and biologically active molecules and 1,4-dihydropyridines are an important class of compounds with interesting biological activities such as vasolidator, antitumor, antidiabetic, bronchodilator and anti-atherosclerotic activities. Excellent yields and short reaction timesare related to the highefficiency of SBA-Pr-SO3H that the reactions take place easily in its nano-pores. Mild reaction conditions and easy work-up procedures are other advantages of this green method.