A new convenient method for the preparation of heterocyclic mono- and bis-derivatives on the base of uracils and ftorotan with 18-crown-6-complex as catalyst was described. The structure and composition of synthesized compounds has been confirmed by data of elemental analysis, IR- and NMR1Н-spectra. It was discovered that some of compound which synthesized applies to a little toxic preparations: value of their LD50 are from 289 to 177 mg/kg. Image of chemical structure of the compounds which synthesized to structure of antitumour drug 5-fluorouracil, values of their toxicity parameters allows to consider these compounds as potential medical antitumour facilities.
