Synthesis of Sb(iii)-immobilized on nitrogen-doped mesoporous silica nanotubes for efficient and green preparation of pyrazolopyranopyrimidines: comprehensive characterization, green chemistry evaluation and computational antifungal profiling against 5TZ1.
Jafari Taadi Zahra Z, Moradi Leila L, Moazeni Bistgani Azam A
In this study, a novel heterogeneous nanocatalyst, Sb(iii) immobilized on nitrogen-doped mesoporous silica nanotubes (N-MSNTs/Sb(iii)), was successfully synthesized. This catalyst was then applied in a one-pot, four-component synthesis of pyrazolopyranopyrimidine derivatives via the condensation of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes, and barbituric/thiobarbituric acid. Comprehensive characterization using FT-IR, FE-SEM, EDS, HR-TEM, XRD, and BET/BJH analyses confirmed its structural features. Notably, HR-TEM revealed hollow nanotubular structures with an inner diameter of ∼23 nm and a wall thickness of 27 nm. Moreover, BET/BJH measurements exhibited a type IV isotherm, indicative of a highly porous structure, with a remarkable specific surface area of 1255 m2 g-1, a pore volume of 0.71 cm3 g-1, and an average pore diameter of 2.26 nm. Catalytic evaluations demonstrated the superior performance of N-MSNTs/Sb(iii) in aqueous media at room temperature, affording the target compounds in high yields (78-96%) within short reaction times (35-85 min). This remarkable efficiency stems from synergistic activation of support by the nitrogen sites and active Sb(iii) Lewis acidic species. Furthermore, the catalyst exhibited excellent stability, maintaining its initial activity over five consecutive reuse cycles. Finally, molecular docking simulations were performed against the antifungal target 5TZ1. The results confirmed that the carbonyl and NH groups within the synthesized molecular scaffolds establish favorable binding interactions, highlighting the promising drug-like properties of the final products.