Design,synthesis And Biological Evaluation Of Anti-Lassa Virus Compounds Based On Benzimidazole Scaffold

Lassa virus（LASV）,a negative-stranded RNA virus,belongs to the family Arenaviridae,the genus Mammarenavirus,and is classified as a Category A bioterrorism agent by the US Centers for Disease Control and Prevention.LASV causes a virulent viral hemorrhagic fever with strong infectivity and high lethality.Currently,treatment for Lassa fever is supportive and clinical antiviral agents are limited to ribavirin,with no approved vaccine and specific drugs for anti-LASV.The outbreak of Lassa fever will pose a major threat to public health and biodefense;therefore,research on effective anti-LASV drugs is of great significance both in terms of epidemic control and biosecurity.In order to overcome the burden and challenges posed by LASV,there is an urgent need to find new anti-LASV drugs.In this study,we carried out structural modification,compound synthesis and activity studies based on the benzimidazole scaffold.Two series of 22 novel benzimidazole scaffold lassa virus inhibitors with independent intellectual property rights were synthesized by multi-step reactions including substitution reactions,nitro reduction,cycloaddition,reductive amination,and the Wittig reaction.Third-generation lentiviral techniques were used to establish a lentiviral model carrying the LASV GPC gene to evaluate viral entry inhibitors.The surface plasmon resonance（SPR）was further used to validate the binding activity of potential compounds with the target protein.Most of the compounds exhibited promising antiviral activity.Compounds 7d-Z,7h-Z,13c,13d and13f showed relatively excellent activity with IC₅₀ values ranging from 7.58 n M to 15.46n M and SI values above 1251.The five compounds represented possessed a low equilibrium dissociation constant(KD<8.2510^-7M)and exhibited very strong binding affinity in SPR studies.The drug-likeness of these five potential compounds were predicted and calculated using the online tool Swiss ADME,and the compounds 7d-Z,7h-Z,13c,13d and 13f were found to meet the Lipinski and Veber rules for the drug-likeness and value for further deeper study.Among them,it is noteworthy that compound 7h-Z has a large conjugated system through the introduction of naphthophenyl,which makes the compound more structurally stable and interestingly also exhibits optimal antiviral activity(IC₅₀=7.58 n M)with an SI up to 2496 which is 2-fold higher than the positive drug LHF-535（1208）and can be further developed as a LASV inhibitor candidate compound.Preliminary structure-activity relationship（SAR）studies suggest that compounds with lipophilicity and larger space substituents may have higher antiviral activity and larger safety margin.This study will provide a reference for further development of novel anti-LASV highly active compounds.