Purine nucleoside analogues used antiviral agents

Structure of some of the purine nucleoside analogues used as antiviral agents. 

Pradere et al. described the synthesis of bis(pivaloylo g methyl) prodrugs of (F)-[4 -phosphonobut-2 -en-l -yl]purine nucleosides (55) using a one-step Mitsunobu reaction. The authors evaluated these compounds for their antiviral activities against a number of DNA and RNA viruses and some of the compounds showed submicromolar activity. Modification of the side chain or base in these analogues may lead to the discovery of new antiviral agents. 

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