Synthesis, crystal structure, spectroscopic characterization, Hirshfeld surface analysis, molecular docking studies and DFT calculations, and antioxidant activity of 2-oxo-1,2-dihydroquinoline-4-carboxylate derivatives

A series of hydroquinolines derivatives (2a-2c) have been achieved by a cyclocondensation reaction. The synthesis of 2-oxo-1,2-dihydroquinoline-4-carboxylic acid derivatives (3a-3c) has been carried out using alkylation reactions under phase transfer catalysis (PTC) conditions. The prepared products were characterized through spectroscopic NMR 1H and 13C, IR and single crystal X-ray diffraction techniques. 2D and 3D Hirshfeld surfaces (for 3a and 3b) studies were realized to understand non-bonding intermolecular interactions in solid phase crystal packing of the compound. With the optimized structures, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and clouds were obtained and evaluated. Good agreement was found between the calculated results and experimental data. Furthermore, the molecular docking study is performed to investigate binding patterns of the synthesized molecules (3a and 3b) into 1M17 inhibitor using Auto-Dock Vina program. The antioxidant activity of compounds (3a-3c) has been evaluated using DPPH free radical scavenging, ferric reducing (FRAP) power and beta-carotene kinetic blanching assays. Both DPPH and FRAP methods confirmed that 3b had the best antioxidant activity followed by 3c. On the other hand, beta-carotene bleaching assay showed the high activity of the product 3a. (C) 2019 Published by Elsevier B.V.