Novel anti-viral agents of Formula ##STR00001## wherein: A represents OR.sup.1, NR.sup.1R.sup.2, or R.sup.1 wherein R.sup.1 and R.sup.2 are hydrogen, C.sub.1-6alkyl, aryl, heteroaryl, arylalkyl, or heteroarylalkyl; or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group; B represents C(O)R.sup.3 wherein R.sup.3 is C.sub.1-6alkyl, aryl, heteroaryl, arylalkyl, or heteroarylalkyl; C represents C.sub.1-6alkyl, aryl, heteroaryl or heterocyclyl; D represents a saturated or unsaturated optionally substituted 6-membered heterocyclic ring; E represents hydrogen or C.sub.1-6alkyl; F represents hydrogen, C.sub.1-6alkyl, aryl or heteroaryl; and G represents hydrogen, C.sub.1-6alkyl, heterocyclylalkyl, arylalkyl or heteroarylalkyl; and salts, solvates and esters thereof, processes for their preparation and methods of using them in HCV treatment are provided.