L-Proline Catalyzed Knoevenagel Condensation of Aldehydes with Active Methylene Compounds and Their Molecular Modeling Studies for Anti-SARS CoV-2 Potentials

An efficient one-pot synthesis of 2-alkylidene/arylidene derivatives was reported from active methylene compounds such as malononitrile/ethyl cyanoacetate/5-methyl-2,4-dihydro-3H-pyrazol-3-one and aldehydes in the presence of 10 mol% of L-proline (ethanol at room temperature). All derivatives were obtained in good to excellent yields. The structures of the synthesized compounds were confirmed from their FTIR (Fourier-transform infrared spectroscopy), 1H-NMR (Proton nuclear magnetic resonance), and mass spectroscopy. The importance of these compounds is predicted from their SAR (structure-activity relationship) study. Moreover, these newer compounds were further docked into various therapeutic targets of the SARS-CoV-2 (severe acute respiratory syndrome–related coronavirus) virus. Results from our molecular docking suggested that these compounds have good inhibitory properties on the SARS- CoV-2 virus. L-proline (bifunctional organic catalyst) is found to be the best catalyst for the synthesis of different condensed products from active methylene compounds and aldehydes.