Bioinspired NiCoO2 nanocomposites derived from Moringa oleifera as a recyclable catalyst for the synthesis of pyrazolopyrano[2,3-d]pyrimidine with potent antimicrobial efficiency

A green synthetic approach was developed for the preparation of a NiCoO₂ nanocomposite using an aqueous extract of Moringa oleifera as both a reducing and stabilizing agent. The synthesized NiCoO₂ nanocomposite exhibited high crystallinity and measurable antimicrobial activity. Detailed characterization using XRD, UV-visible spectroscopy, fluorescence spectroscopy, FTIR, BET, SEM, EDS, elemental mapping, and TEM analyses confirmed its crystalline structure, elemental composition, thermal stability, surface functional groups, and morphological features. The nanocomposite and the synthesized products were evaluated for antimicrobial activity against S. aureus, B. cereus, P. vulgaris, and S. typhimurium, demonstrating inhibitory effects against the tested microorganisms. The NiCoO₂ nanocomposite was also employed as a heterogeneous catalyst in a one-pot multicomponent condensation reaction of aldehydes, hydrazine hydrate, barbituric acid, and ethyl acetoacetate under ultrasonic conditions, affording pyrazolopyrano[2,3-d]pyrimidine derivatives in yields of up to 98% within short reaction times. The catalyst retained its activity over five consecutive cycles, indicating good recyclability. Furthermore, the synthesized heterocycles exhibited antimicrobial activity against both Gram-positive and Gram-negative bacterial strains. Molecular docking studies revealed that all synthesized compounds (1-11) exhibited favorable binding affinities toward the 4COX enzyme, with docking scores higher than that of the reference drug indomethacin, suggesting their potential for further biological evaluation.