MOF-199 as an Efficient Metal Organic Framework Catalyst for the Synthesis of Spiro[Indoline-3,4′-Pyrano[2,3-c]Pyrazole] Derivatives.

Metal organic frameworks are frameworks of 1–3 D formed by the interaction between metal ions/clusters and organic molecules. The high specific surface area and large pore volume of these molecules render them as ideal candidates for catalysis applications. A metal-organic framework (MOF-199) has been synthesized by facile chemical method and characterized by infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM) and energy dispersive X-ray (EDS) technique. In this study an efficient eco-friendly procedure for the synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives has been developed through a four-component condensation of isatin and its derivatives, hydrazine hydrate, ethyl acetoacetate, and malononitrile/ethyl cyanoacetate, in the presence of catalytic amount of MOF-199 in H2O at room temperature. The advantages of this protocol include mild reaction condition, green, and nontoxic solvent, high yield, easy separation, reusability of the catalyst and operational simplicity. [ABSTRACT FROM AUTHOR]