Compounds of formula (I), and pharmaceutically acceptable salts thereof:
wherein
R₁ is hydroxy or amino;
R₂ is hydrogen or amino;
R₃ is hydrogen, hydroxymethyl or acyloxymethyl;
R₄ is a group of formula:
wherein
R₅ and R₆ are independently selected from hydrogen, C₁₋₆ alkyl and optionally substituted phenyl; or
R₃ and R₄ together are:
wherein
R₆ is as defined above;
having antiviral activity, processes for their preparation and their pharmaceutical use.
式 (I) 的化合物及其药学上可接受的盐类:
其中
R₁ 是羟基或
氨基;
R₂ 是氢或
氨基
R₃ 是氢、羟甲基或酰氧基甲基;
R₄ 是式中的基团:
其中
R₅ 和 R₆ 独立选自氢、C₁₋₆ 烷基和任选取代的苯基;或
R₃ 和 R₄ 合在一起为
其中
R₆ 如上文所定义;
具有抗病毒活性,其制备工艺和药物用途。