A theoretical and experimental study on ecofriendly-one-pot synthesis of pyrazolopyranopyrimidines catalysed by CuO functionalized montmorillonite

[Display omitted] •CuO incorporated onto N,S-functionalized-Mont-K10 was characterized.•Metal-ligand interactions in catalyst assessed via computational chemistry.•CuO-Mont/SiO2-EPiMl-SO3H was applied as a recyclable catalyst in MCRs.•CuO-Mont/SiO2-EPiMl-SO3H was recycled for 7 runs with slight loss of activity. In this project, with the aim of benefiting from the advantage of chemistry of copper catalyst and montmorilonite-K10 clay (Mont), cost-effective and proficient catalyst support, a new hybrid system composed of CuO incorporated onto functionalized-Mont was designed and prepared after multi-steps processes (CuO-Mont/SiO2-EPiMl-SO3H). The hybrid system was fully characterized and the application of that was investigated as heterogeneous catalyst for the preparation of pyrazolopyranopyrimidines (PPPs) via one-pot reaction under mild conditions. Moreover, we have described metal–ligand interactions in a CuO-Mont/SiO2-EPiMl-SO3H complex model employing quantum chemistry methods. In fact, we analyzed the mathematical properties of electron density functions via density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) computations. The achievement of highest yields of pure products with the lowest amount of CuO-Mont/SiO2-EPiMl-SO3H catalyst, simple workup with seven times recyclability that confirmed by ICP-AES analysis, proved the prodigious potential of the CuO-Mont/SiO2-EPiMl-SO3H for the above-mentioned reaction.