ZnCl2/SiO2 as a New Catalyst for the Eco-Friendly Synthesis of N-Thiocarbamoyl Pyrazoles and Thiosemicarbazones with Antioxidant and Molecular Docking Evaluation as (UppS) Inhibitor

The study aimed at a novel catalytic eco-friendly one-pot reaction for the synthesis of some new thiosemicarbazone and N-thiocarbamoyl pyrazole derivatives. The prepared and characterized silica-supported zinc chloride (ZnCl2/SiO2) catalyst has been presented for promoting the one-pot reaction between isothiocyanates (1 mmol), hydrazine (1.2 mmol) and 1,3- dicarbonyl (1 mmol) compounds under solvent-free conditions. The identification data explained that the thiosemicarbazones products were obtained in the case of using ethyl acetoacetate as an example of 1,3-dicarbonyl compounds and N-thiocarbamoyl pyrazole derivatives products were obtained in the case of using acetylacetone as an example of 1,3- dicarbonyl compounds. The presented catalyst silica-zinc chloride has been considered an eco-friendly and recyclable catalyst compared to the other reported catalyst. The biological activity of the synthesized compounds targeting the bacterial cell wall was predicted by the molecular docking as an undecaprenyl pyrophosphate synthase (UppS) inhibitor. Antioxidant data revealed the compounds 2a, 3d, 3e, 3f, 3g, 3h, and 3j to be promising antioxidant agents compared to ascorbic acid as a reference molecule.