1,3,4-oxadiazole: a privileged structure in antiviral agents.

1,3,4-oxadiazole, a privileged structure, endows its derivatives with broad and potent biological functions, especially in antiviral activities, including anti-HIV, anti-HCV, anti-HBV, anti-HSV activities, etc. Molecular modeling and pharmacokinetic studies have demonstrated that the introduction of 1,3,4-oxadiazole ring to the inhibitors can change their polarity, flexibility as well as metabolic stability, and 1,3,4-oxadiazole scaffold can also act as acceptors of hydrogen bonds formation, which make it possible to be used as a isosteric substituent for amide or ester groups. This review focuses on the recent advances in the synthesis of 1,3,4-oxadiazole ring and mainly the discovery, biological activities investigations and structural modifications of several distinct classes of 1,3,4-oxadiazoles as potent antiviral agents. In addition, the binding models of some representative 1,3,4-oxadiazoles were also discussed, which provide rational explanation for their interesting antiviral activities, and also pave the way for further optimization of 1,3,4- oxadiazole based antiviral agents.