Ag/TiO2 nano-thin films as robust heterogeneous catalyst for one-pot, multi-component synthesis of bis (pyrazol-5-ol) and dihydropyrano[2,3-c]pyrazole analogs

The present methodology describes two efficient, eco-friendly, and simple routes for the cascade synthesis of biologically relevant pyrazole scaffolds using Ag/TiO2 nano-thin films as a green, robust, and recyclable catalyst. Ag/TiO2 nano-thin films were successfully applied for the synthesis of bis (pyrazol-5-ol) and dihydropyrano[2,3-c]pyrazole derivatives in the one-pot, multicomponent manner. These operationally straightforward procedures have merits, including high yields of products from a simple set of readily available starting materials, eco-friendliness, and heterogeneity and reusability of catalyst. Also, it was observed that the catalyst was highly stable during the reaction and several reuse times without observable losses in catalytic performance. (C) 2017 King Saud University. Production and hosting by Elsevier B.V.