ZIF-8 nanoparticles as an efficient and reusable catalyst for the Knoevenagel synthesis of cyanoacrylates and 3-cyanocoumarins

International audienceZeolitic imidazolate framework (ZIF-8) particles with an average size of ca. 355 nm and a specific surface area of 1786 m2.g−1 were used as an heterogenous catalyst for the Knoevenagel synthesis of α,β-unsaturated cyanoesters and 3-cyanocoumarins. The preparation of 3-cyanocoumarins was efficiently achieved using DMF as the solvent and conducting the condensation at 80 °C. When the reaction was performed in ethanol, only the intermediates α,β-unsaturated cyanoesters were obtained. The ZIF-8 catalyst can be reused up to five times without any degradation in activity. SEM and XRD analyses demonstrate the high stability of ZIF-8 crystals during the recycling test