Anti-viral agents of Formula (I) ##STR00001## wherein: A represents hydroxy; D represents aryl or heteroaryl; E represents hydrogen, C.sub.1-6alkyl, aryl, heteroaryl or heterocyclyl; G represents hydrogen or optionally substituted C.sub.1-6alkyl; J represents C.sub.1-6alkyl, heterocyclylalkyl, arylalkyl or heteroarylalkyl; and salts, solvates and esters thereof; provided that when A is esterified to form --OR where R is selected from straight or branched chain alkyl, aralkyl, aryloxyalkyl, or aryl, then R is other than tert-butyl; processes for their preparation, pharmaceutical compositions comprising them, and methods of using them in HCV treatment are provided.