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 is amino or, when R.sub.1 is hydroxy or amino, R.sub.2 may also be hydrogen; R.sub.3 is hydrogen, hydroxymethyl or acyloxymethyl; R.sub.4 is a group of formula: ##STR2## R.sub.5 and R.sub.6 are independently selected from hydrogen, C.sub.1-6 alkyl and optionally substituted phenyl; or R.sub.3 and R.sub.4 together are: ##STR3## wherein R.sub.6 is as defined above; having antiviral activity, to processes for their preparation and their use as pharmaceuticals.
式(I)的化合物及其药学上可接受的盐,其中R.sub.1是羟基、
氨基、
氯或OR.sub.7,其中R.sub.7是C.sub.1-6烷基、
苯基或
苯基C.sub.1-2烷基,其中任一
苯基基团可以被选自卤素、C.sub.1-4烷基或C.sub.1-4烷
氧基的一个或两个取代基所取代;R.sub.2是
氨基,或当R.sub.1是羟基或
氨基时,R.sub.2也可以是
氢;R.sub.3是
氢、
羟甲基或酰
氧甲基;R.sub.4是下式的基团:##
STR2## R.sub.5和R.sub.6独立地选自
氢、C.sub.1-6烷基和可选取代的
苯基;或R.sub.3和R.sub.4一起是:##
STR3## 其中R.sub.6如上定义;具有抗病毒活性,其制备过程及其作为药物的用途。