Design, Synthesis and Biological Exploration of Novel N-(9-Ethyl-9H-Carbazol-3-yl)Acetamide-Linked Benzofuran-1,2,4-Triazoles as Anti-SARS-CoV-2 Agents: Combined Wet/Dry Approach Targeting Main Protease (M(pro)), Spike Glycoprotein and RdRp.

A novel series of substituted benzofuran-tethered triazolylcarbazoles was synthesized in good to high yields (65-89%) via S-alkylation of benzofuran-based triazoles with 2-bromo-N-(9-ethyl-9H-carbazol-3-yl)acetamide. The inhibitory potency of the synthesized compounds against SARS-CoV-2 was evaluated by enacting molecular docking against its three pivotal proteins, namely, M(pro) (main protease; PDB ID: 6LU7), the spike glycoprotein (PDB ID: 6WPT), and RdRp (RNA-dependent RNA polymerase; PDB ID: 6M71). The docking results indicated strong binding affinities between SARS-CoV-2 proteins and the synthesized compounds, which were thereby expected to obstruct the function of SARS proteins. Among the synthesized derivatives, the compounds 9e, 9h, 9i, and 9j exposited the best binding scores of -8.77, -8.76, -8.87, and -8.85 Kcal/mol against M(pro), respectively, -6.69, -6.54, -6.44, and -6.56 Kcal/mol against the spike glycoprotein, respectively, and -7.61, -8.10, -8.01, and -7.54 Kcal/mol against RdRp, respectively. Furthermore, the binding scores of 9b (-8.83 Kcal/mol) and 9c (-8.92 Kcal/mol) against 6LU7 are worth mentioning. Regarding the spike glycoprotein, 9b, 9d, and 9f expressed high binding energies of -6.43, -6.38, and -6.41 Kcal/mol, accordingly. Correspondingly, the binding affinity of 9g (-7.62 Kcal/mol) against RdRp is also noteworthy. Furthermore, the potent compounds were also subjected to ADMET analysis to evaluate their pharmacokinetic properties, suggesting that the compounds 9e, 9h, 9i, and 9j exhibited comparable values. These potent compounds may be selected as inhibitory agents and provide a pertinent context for further investigations.