Synthesis of novel pyrrolo[1,2-a]quinoline derivatives as a new class of anti-inflammatory and antimicrobial agents: An approach to single crystal X-ray structure, Hirshfeld surface analysis and DFT studies

We report the synthesis and characterisation of pyrrolo[1,2-a]quinoline derivatives 3a-c. The synthesised compounds were characterised by FTIR, ¹H NMR, ¹³C NMR, and mass spectrometry. The single crystal diffraction analysis revealed 3a crystallizes in monoclinic system with the space group P2₁/. Hirshfeld surfaces and two-dimensional (2D) fingerprint plots are employed to quantitatively characterize the influence of non-covalent interactions within the crystal lattice of 3a. The molecule geometry was optimised employing B3LYP/6-311++G(d,p) theoretical approach, and comparison was studied between the optimized structural parameters, including bond lengths, bond angles, and dihedral angles, and their corresponding experimental values. The compound's molecular structure, HOMO-LUMO, and molecular electrostatic potential (MEP) surface were calculated using the density functional theory (DFT) Becke-3-Lee Yang Parr (B3LYP) technique with the 6-311++G(d,p) basis set in the ground state. The synthesized derivatives undergo meticulous in-vitro evaluations for anti-inflammatory and antimicrobial potential. The Compound 3a has shown remarkable antibacterial efficacy against S. aureus and E. coli, alongside potent antifungal performance against A. niger and C. albicans. Whereas, the compound 3b has shown substantial anti-inflammatory activity compared to Ibuprofen.