Efficient synthesis of Benzylidenethiazolidine-2, 4-dione derivatives using organo catalyst (DABCO) in aqueous media via simple Knoevenagel condensation reaction

A simple, selective and environment-friendly procedure has been developed for simple Knoevenagel condensation reaction between aromatic aldehydes and active methylene compound (Thiazolidine-2,4-dione) using 1,4-diazabicyclo[2.2.2]octane (DABCO) as an efficient organocatalyst in the presence of aqueous ethanol solvent. The current methodology has the advantages of operational simplicity, mild reaction conditions and good to high yield of the products (84-91%). The synthetic method is simple as no special apparatus for work up are required and the compound formed is filtered and purified just by simple crystallization. The structure of different substituents containing electron-withdrawing groups (such as nitro group, halide) or electron-donating groups (such as hydroxyl group, alkoxyl group) did not showed strongly obvious effects in terms of reaction time and yield of products. Products are characterized by IR, ^1HNMR, ^13CNMR, mass spectral analysis and are in a state of high purity.