A hydrazine functionalized UiO-66(Hf) metal–organic framework for the synthesis of quinolines via Friedländer condensation†
A hydrazine functionalized Hf-UiO-66 metal–organic framework (MOF) (called 1) was prepared using the traditional solvothermal method and it was characterized completely. The material showed high chemical stability in various solvent systems. The activated material (called 1′) was successfully used as a solid heterogeneous catalyst for the synthesis of quinolone scaffolds in a modified Friedländer synthesis. The catalyst was able to produce 95% yield of the product 3-acetyl-2,4-dimethylquinoline via Friedländer condensation of 2-aminoacetophenone and acetylacetone as starting materials at 100 °C. It also exhibited a broad substrate scope in this catalytic reaction. Various control experiments were carried out with respect to the activity of the presented catalyst which clearly indicated its active role. The stability and recyclability of the catalyst were also examined. A series of control experiments for this catalysis have shown that the Lewis acidic metal nodes and Brønsted acidic –NHNH2 functional groups of linker play active roles in the catalysis.