Compounds of formula I: including any possible stereoisomers thereof, wherein: R1 is hydrogen, -C(=O)R6 or -C(=O)CHR7-NH2； R2 is hydrogen； or C1-C6alkyl or phenyl, either of which is optionally substituted with 1, 2 or 3 substituents each independently selected from halo, C1-C6alkyl, C2-C6-alkenyl and C1-C6alkoxy, hydroxy or amino, or R2 is naphtyl； or R2 is indolyl, R3 is hydrogen, C1-C6alkyl, benzyl； R4 is hydrogen, C1-C6alkyl, benzyl； or R3 and R4 together with the carbon atom to which they are attached form C3-C7cycloalkyl； R5 is C1-C10alkyl, C3-C7-cycloalkyl, benzyl, or phenyl, any of which being optionally substituted with 1, 2 or 3 substituents each independently selected from hydroxy, C1-C6alkoxy, amino, mono- and diC1-C6alkylamino； R6 is C1-C6 alkyl； R7 is C1-C6 alkyl； R8 is hydrogen or halogen； or a pharmaceutically acceptable salt or solvate thereof are useful in the prophylaxis or treatment of HCV infections.
