Abstract: New uracil derivatives of the general formula: ##STR1## wherein R.sup.1 stands for a hydrogen atom or a grouping of the formula: ##STR2## R.sup.2 for a hydrogen atom, an alkyl group or a phenyl group and R.sup.3 for an alkyl group or a phenyl group, with the proviso that when both R.sup.1 and R.sup.2 stand for a hydrogen atom, R.sup.3 stands for a phenyl group or a straight chain alkyl group with 3.about.11 carbon atoms, that when R.sup.1 stands for a hydrogen atom and R.sup.2 for methyl group, R.sup.3 stands for an alkyl group with at least 2 carbon atoms or a phenyl group, and that when R.sup.1 stands for a hydrogen atom and R.sup.3 for methyl group, R.sup.2 stands for an alkyl group with at least 2 carbon atoms or a phenyl group. These uracil derivatives are prepared by reacting 5-fluorouracil with an .alpha.-haloalkyl carboxylate or with an aldehyde diacylate or by hydrolyzing a 1,3-bis(acyloxymethyl)-5-fluorouracil with an acid or alkali.

Abstract: A process for efficiently preparing 1-(2-tetrahydrofuryl)-5-fluorouracil useful as an antitumor agent or an antiviral agent which comprises reacting 5-fluorouracil with 2,3-dihydrofuran. This reaction proceeds advantageously in the presence of a reaction accelerator such as a Lewis acid in a polar solvent such as pyridine.