Compounds of formula (I) and pharmaceutically acceptable salts thereof:
wherein
R₁ is hydroxy, amino, chloro or OR₇
wherein
R₇ is C₁₋₆ alkyl, phenyl or phenyl C₁₋₂ alkyl either of which phenyl moieties may be substituted by one or two substituents selected from halo, C₁₋₄ alkyl or C₁₋₄ alkoxy;
R₂ is amino or, when R₁ is hydroxy or amino, R₂ may also be hydrogen;
X is -CH₂CH₂- or a moiety of structure (a), (b) or (c):
wherein
n is 1 or 2; and
R₃ is hydrogen or acyl;
R₄ is a group of formula:
wherein
R₅ and R₆ are independently selected from hydrogen,
C₁₋₆ alkyl and optionally substituted phenyl; having anitiviral activity, processes for their preparation and their use as pharmaceuticals.
Compounds of formula (I) and pharmaceutically acceptable salts thereof: ##STR1## wherein R.sub.1 is hydroxy, amino, chloro or OR.sub.7 wherein R.sub.7 is C.sub.1-6 alkyl, phenyl or phenyl C.sub.1-2 alkyl either of which phenyl moieties may be substituted by one or two substituents selected from halo, C.sub.1-4 alkyl or C.sub.1-4 alkoxy; R.sub.2 amino or, when R.sub.1 is hydroxy or amino, R.sub.2 may also be hydrogen; X is --CH.sub.2 CH.sub.2 -- or a moiety of structure (a), (b) or (c): ##STR2## wherein n is 1 or 2; m is 0, 1 or 2; and R.sub.3 is hydrogen or acyl; R.sub.4 is a group of formula: ##STR3## wherein R.sub.5 and R.sub.6 are independently selected from hydrogen, C.sub.1-6 alkyl and optionally substituted phenyl; having antiviral activity, processes for their preparation and their use as pharmaceuticals.