(searched for: (10.5155/eurjchem.3.3.310-313.659))
European Journal of Chemistry, Volume 3, pp 310-313; doi:10.5155/eurjchem.3.3.310-313.659
The Knoevenagel condensation between isatins and active methylene compounds like malononitrile and ethyl cyanoacetate to prepare 2-oxoindolin-3-ylidene malononitrile/ cyanoacetates is described. The reactions occur in the presence of sulfonic acid functionalized silica SBA-15 (SBA-Pr-SO3H) in an aqueous medium giving excellent yields of the products in short reaction times. SBA-Pr-SO3H with a pore size of 6 nm is found to be an efficient and environmentally benign catalyst for this reaction.