Magnetically recoverable WFe2O4/rGO catalyzed green synthesis of thiadiazolo[2,3-b] quinazolin-6(7H)-one derivatives: structural, DFT, and molecular docking studies

Abstract

A facile, one-pot multicomponent protocol is reported for the synthesis of biologically active thiadiazolo[2,3-b] quinazolin-6(7H)-one derivatives from 2-amino-5-phenyl-1,3,4-thiadiazole, dimedone, and substituted aromatic aldehydes, catalyzed by magnetic WFe2O4/rGO NPs synthesized via a hydrothermal route. The catalyst, characterized by FT-IR, XRD, SEM, EDX, BET, VSM, TGA, XPS, Raman spectroscopy and zeta potential, afforded the target heterocycles in short reaction times and high yields at room temperature, with easy magnetic recovery and excellent reusability. Molecular docking of compounds V1–V6 revealed favorable computational binding affinities against DNA gyrase as a putative target, while DFT calculations on V1, V2, V5, and V7 (B3LYP/6-311++G(d,p)) provided optimized geometries, thermodynamic parameters, global reactivity descriptors, and HOMO–LUMO energy gaps. Together, these experimental and computational results establish WFe2O4/rGO NPs as an efficient, sustainable catalyst for green heterocyclic synthesis and highlight the preliminary antibacterial properties of the synthesized thiadiazolo quinazoline derivatives.