| 摘要 |
Antivirally active compounds of the formula <IMAGE> I wherein R1 represents hydroxy, acyloxy derived from an aliphatic acid having 2-18 carbon atoms or a heterocyclic carboxylic acid containing nitrogen atom(s), lower alkoxycarbonyloxy, aminoacyloxy or carboxyalkanoyloxy; R2 represents lower alkoxy; R3 represents hydrogen or lower alkoxy; and R4 represents phenyl which may be substituted by one or more substituents selected from the group consisting of lower alkyl, lower alkoxy, benzyloxy, allyloxy, alkylthio, dialkylamino, amino, cyano, hydroxy, halo and alkylenedioxy; or pyridyl, furyl, thienyl or pyrrolyl which may be substituted by lower alkyl, pharmaceutical compositions containing them and a process for the preparation of those compounds of formula I which are novel. |
