Design and development of novel fluorescent oxo-fluoro quinoline (E)-chalcone derivatives via Claisen–Schmidt reaction using Al-SrTiO₃ as a catalyst and its BSA protein binding studies

Abstract

Novel fluorescent oxo-fluoro quinoline (E)-chalcone derivatives were synthesized using a new Aluminum Strontium Titanium Trioxide (Al-SrTiO₃) solid catalyst. The Al-SrTiO₃ catalyst was analyzed by spectroscopic techniques like Fourier Transform Infrared (FT-IR), X-Ray Powder Diffraction, absorption, Scanning Electron Microscopy, SEM-Mapping, Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis and Raman spectroscopy. The novel precursors 2-(4-fluorophenoxy)quinoline-3-carbaldehyde derivatives (3a, 3b) were synthesized from 2-chloro-3-formyl quinoline and were subsequently used to synthesize the oxo-fluoro quinoline-based E-chalcones derivatives (5a–x). The chemical structure of 5a–x were investigated by FT-IR, ¹H and ¹³C-NMR, 2D-NMR and high-resolution mass spectroscopy. Further, molecular docking studies on the hit compound 5t indicated hydrogen bond interaction with Bovine Serum Albumin at amino acids Arginine-194, 198 and 217 with bond lengths of 2.1, 2.2 and 2.2 Å, respectively. The calculated Gibbs free energy value was −5.84 kJ mol⁻¹, while the experimental value of −27.82 kJ mol⁻¹ was obtained from emission spectroscopy.

Graphical Abstract

Keywords:

• Claisen–Schmidt
• 2D-NMR
• oxo-fluoro quinoline

Additional information

Funding

The authors gratefully acknowledge the financial support of the Durban University of Technology (DUT). Prof M. Ilanchelian acknowledges the DST-SERB-EEQ project [no. EEQ/2021/000469], Bharathiar University Coimbatore, India for the financial support.