| 摘要 |
Compounds of the formula: <IMAGE> (I) wherein R1, R3 and R4 each independently represents a hydrogen atom or a protecting group; R2 represents a halogen atom or a group of formula -NRa Rb (where Ra and Rb, which may be the same or different, each represents a hydrogen atom or an alkyl group; or Ra and Rb may be linked to form, together with the nitrogen atom to which they are attached, a heterocyclic ring which optionally contains a further heteroatom); and their physiological equivalents as well as salts thereof with acids, exhibit antiviral activity against RNA viruses such as Influenza and/or are intermeidates for the preparation of antivirally active compounds. |
