A novel uridine derivative of the formula (I):
 wherein R¹ is acyloxy, R² is hydrogen, acyloxy, etc., R³ is aralkyloxy, acyloxy, etc., R⁴ is hydrogen, acyloxy, etc., R is hydrogen or a lower alkyl, and Y is fluorine or trifluoromethyl, and a process for preparing the same are provided. The uridine derivative (I) of the present invention exhibits an excellent anti-tumor activity in vivo.
                            本发明提供了一种具有以下结构的新型
尿苷衍
生物(I):其中R¹为酰氧基,R²为氢、酰氧基等,R³为芳基氧基、酰氧基等,R⁴为氢、酰氧基等,R为氢或较低的烷基,Y为
氟或三
氟甲基,以及制备该化合物的方法。本发明的
尿苷衍
生物(I)在体内展现出优异的抗肿瘤活性。