Heterocyclic compounds play a critical role in medicinal chemistry, and many available drugs contain heterocyclic rings. A six-membered heterocyclic compound, pyridine, showed various applications, including being an important solvent, reagent, and precursor in agrochemicals and pharmaceuticals. Due to the increase in drug resistance, there is an apparent medical need to develop new antiviral agents. Various derivatives of pyridine scaffold display broad biological activities such as anti-microbial, antiviral, antioxidant, anti-diabetic, anti-cancer, anti-malarial, analgesic, and antiinflammatory activities. Furthermore, they display psychopharmacological, antagonistic, anti-amoebic agents, and anti-thrombic activities. Due to the high importance of pyridine derivatives, in the present review, we tried to collect and classify many pyridine derivatives based on their structures from 2000 to 2020. Pyridine derivatives were classified into two general categories, including pyridine containing heterocycles and pyridine fused rings. The structure-activity relationship (SAR) and the action mechanism of derivatives were also investigated. According to the recent studies, these derivatives exhibited good antiviral activity against different types of viruses such as the human immunodeficiency viruses (HIV), the hepatitis C virus (HCV), the hepatitis B virus (HBV), respiratory syncytial virus (RSV), and cytomegalovirus (CMV). These derivatives inhibited viral application with different action mechanism such as RT inhibition, polymerase inhibition, inhibition of RNase H activity, inhibition of maturation, inhibition of the viral thymidine kinase, AAK1 (Adaptor-Associated Kinase 1) inhibition, GAK (Cyclin G-associated kinase) inhibition, inhibition of post-integrational event, inhibition of HDAC6, CCR5 antagonistic activity, DNA and RNA replication inhibition, gene expression inhibition, cellular NF-jB signaling pathway and neuraminidase (NA) inhibition, protein synthesis inhibition, and generally inhibition of viral replication cycle. This paper summarized the past and present results about the discovery of novel lead compounds with good antiviral activity. Studies exhibited that almost all of the evaluations were performed by way of in vitro testing. It is necessary to investigate in vivo and clinical testing for better evaluations in the future. We believe that pyridine derivatives can be used as promising antiviral agents and more broad investigations in this field need to be performed.
