Facile Knoevenagel condensation Using Sulfonic Acid Functionalized Nanoporous silica (SBA-Pr-SO3H)

Knoevenagel condensation between barbituric acid and aldehyde was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) and resulted in the formation of arylidene and bis-arylidene barbiturates. Excellent yields and short reaction times are related to the high efficiency of SBA-Pr-SO3H that the reactions take place easily in its nano-pores. SBA-Pr-SO3H as an efficient heterogeneous nanoporous solid acid catalyst which was prepared by silica functionalization with (3-mercaptopropyl) trimethoxysilane followed by oxidation with H2O2, can be easily removed from the reaction mixture by simple filtration, and also recovered and reused without noticeable loss of reactivity.