A novel heterocyclic derivative of formula (I): ##STR1## wherein R.sub.1 represents ##STR2## and R.sub.2 represents hydrogen or acyl. When R.sub.2 is acyl, the derivative can be prepared, for example, by the following process: ##STR3## wherein R.sub.4 is acyl and R.sub.1 is ##STR4## The derivative is less toxic and has radiosensitizing activity and antiviral activity even at a low concentration. Radiosensitizing agents and antiviral agents containing the derivative as active component are also disclosed.
式(I)的新型杂环衍
生物:##STR1## 其中R.sub.1表示##STR2## 而R.sub.2表示氢或酰基。当R.sub.2为酰基时,该衍
生物可以通过以下过程制备:##STR3## 其中R.sub.4为酰基,R.sub.1为##STR4## 该衍
生物毒性较小,即使在低浓度下也具有放射增敏活性和抗病毒活性。还公开了含有该衍
生物作为活性成分的放射增敏剂和抗病毒剂。