Synthesis and Biological Evaluation of Benzothiazolyl-pyridine Hybrids as New Antiviral Agents against H5N1 Bird Flu and SARS-COV-2 Viruses
Nadia H. Metwally, Galal H. Elgemeie, Fatma Gomaa Fahmy
Abstract
High Resolution Image Download MS PowerPoint Slide A novel series of benzothiazolyl-pyridine hybrids 8a – h and 14a – e were produced from the reaction of enamine derivative 4 with each of the arylcyanoacetamides 5a – h and cyanoacetohydrazides 9a – e . The new products were characterized by spectral techniques (IR, 1 H NMR, 13 C NMR, and MS). Biological evaluation of 8a – h and 14a – e in vitro against H5N1 and SARS-COV-2 viruses showed that several compounds had significant activity. Compounds 8f – h, which contain fluorine atoms, have better activity against H5N1 and anti-SARS-CoV-2 viruses than the other compounds included in this study. Compound 8h has a trifluoromethyl group at position-3 of the phenyl ring and exhibits a high activity against H5N1 virus with 93 and 60% inhibition at concentrations of 0.5 and 0.25 μmol/μL, respectively, among the tested compounds, and it also showed anti-SARS-CoV-2 virus with a half-maximum inhibition rate of 3.669 μM, among the remaining compounds. The mechanism of action of 8f – h, which is expected to be repurposed against COVID-19, was investigated. The results showed that the compounds have virucidal effects at different stages of the three mechanisms of action. Furthermore, compounds 8f – h were found to possess CoV-3CL protease inhibitory activities with IC 50 values of 544.6, 868.2, and 240.6 μg/mL, respectively, compared to IC 50 = 129.8 μg/mL of the standard drug lopinavir. Interestingly, compounds 8f – h also showed high inhibitory activity against the H5N1 virus as well as the SARS-CoV-2 virus. Moreover, compounds 8f – h fit admirably into the active site of the SARS-CoV-2 main protease (PDB ID: 6LU7 ) using the molecular docking Moe software 2015.10.