Biomass Derived Carbon Quantum Dots for the Green Synthesis of Aryl Semicarbazones and Their In Silico Evaluation.

In this study, a green and efficient method has been developed for the preparation of aryl semicarbazones using Kigelia pinnata flower-derived carbon quantum dots (KP-CQDs) as a sustainable catalyst. The reaction between various aldehydes/acetophenones and semicarbazide (SC) hydrochloride was carried out smoothly at room temperature in an ethanol-water (1:4) solvent system, and excellent yields (83%-95%) were achieved within a short reaction time of 5-20 min, demonstrating the high catalytic efficiency of KP-CQDs. A total of nine derivatives were synthesized, among which six compounds are reported for the first time. Furthermore, the biological potential of these compounds was investigated through in silico studies. The molecules were subjected to prediction of activity spectra for substances (PASS) online prediction to predict probable biological targets, and based on these predictions, molecular docking was performed against human mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (Protein Data Bank [PDB] ID: 2WYA), hepatitis A virus 3C protease (PDB ID: 1HAV), and foot-and-mouth disease virus (FMDV) 3C protease (PDB ID: 2WV4). On conducting molecular docking, molecules 3f (-15.57 kcal/mol), 3c (-5.61 kcal/mol), and 3e (-9.44 kcal/mol) showed remarkable activity with 2WYA, 1HAV, and 2WV4, respectively. This method offers several key advantages, including the use of a green and reusable CQD catalyst, mild reaction conditions, short reaction times, excellent yields, and the preparation of new semicarbazone derivatives with unexplored biological activities.