A 5-fluorouracil derivative represented by the formula (1): ##STR1## wherein A represents a group represented by ##STR2## wherein R.sup.1 represents a hydrogen atom or OR.sup.5 group, R.sup.2, R.sup.3 and R.sup.5 may be the same or different and each represents a hydrogen atom or a group represented by the following formula (2): ##STR3## wherein R.sup.6 represents an acyl group, R.sup.7 represents a hydrogen atom, a straight or branched alkyl group, a cycloalkyl group, an aralkyl group, a lower alkenyl group or a phenyl group, and n is an integer of 0 to 6, provided that at least one of R.sup.2, R.sup.3 and R.sup.5 is a group represented by the formula (2), and the case wherein R.sup.2 and R.sup.5 are both hydrogen atoms is excluded, R.sup.4 represents a group represented by the formula (2), and X represents an alkylene group or a cycloalkylene group, and an antitumor agent containing the same as an active ingredient.
一种由公式(1)表示的5-
氟尿
嘧啶衍
生物:##STR1## 其中A表示由##STR2## 表示的基团,其中R.sup.1表示氢原子或OR.sup.5基团,R.sup.2、R.sup.3和R.sup.5可以相同也可以不同,每个表示氢原子或由以下公式(2)表示的基团:##STR3## 其中R.sup.6表示酰基基团,R.sup.7表示氢原子、直链或支链烷基、环烷基、芳基烷基、低烯基基团或苯基,n为0至6的整数,但至少有一个R.sup.2、R.sup.3和R.sup.5表示由公式(2)表示的基团,且排除R.sup.2和R.sup.5均为氢原子的情况,R.sup.4表示由公式(2)表示的基团,X表示烷基或环烷基,并且一种含有其作为活性成分的抗肿瘤剂。