The present invention relates to a novel process for preparing uracil derivatives useful as intermediates in the synthesis of uridines having antiviral or antitumor activity or useful as coadjuvants in antiviral therapy, characterized by converting a compound of the formula II into its mesylate derivative of the formula III which is the reduced to give the desired compound of the formula I: ##STR1## in which R.sub.1 is H, halogen, alkyl, aryl or aralkyl.
(EN) The present invention relates to a novel process for preparing uracil derivatives useful as intermediates in the synthesis of uridines having antiviral or antitumor activity or useful as coadjuvants in antiviral therapy, characterized by converting a compound of formula (II) into its mesylate derivative of formula (III) which is the reduced to give the desired compound of formula (I), in which R1 is H, halogen, alkyl, aryl or aralkyl.(FR) On décrit un procédé nouveau de préparation de dérivés d'uracile utiles comme intermédiaires dans la synthèse d'uridines ayant une activité antivirale ou antitumorale ou utiles en tant que coadjuvants dans les traitements antiviraux. Ledit procédé consiste à transformer un composé de formule (II) en son dérivé mésylate de formule (III), qui est ensuite réduit pour obtenir le composé voulu de formule (I), dans laquelle R1 est H, halogène, alkyle, aryle ou aralkyle.