Abstract: A process for preparing 5-fluorouracil, and a novel starting compound for such process, are disclosed. The novel starting compound is 2,4,5-trifluoropyrimidine. The process comprises hydrolyzing the 2,4,5-trifluoropyrimidine at a temperature of about 2.degree. to about 100.degree. C., thereby directly producing the compound 5-fluorouracil.5-Fluorouracil is a known anti-tumor agent, which has been used in the treatment of various types of cancers. In addition, 5-fluorouracil is a starting material for the production of certain types of pro-drugs, which are metabolized to form 5-fluorouracil in the body, such as, for instance, the compound 1-(2-tetrahydrofuryl)-5-fluorouracil.

Abstract: Direct fluorination of uracil, cytosine and their derivatives, in the presence of a non-aqueous solvent, by fluorine gas to produce 5-fluorouracil, 5-fluorocytosine, 5-fluorouracil derivatives and 5-fluorocytosine derivatives is disclosed. The non-aqueous solvent is an acid or alcohol, which can be partly or fully fluorinated or chlorinated, of up to 8 carbon atoms, such as trifluoroacetic acid. Novel compounds produced by the reaction, such as 5,5-difluoro-5,6-dihydro-6-(2,2,2-trifluoroethoxy) uracil are also disclosed. The derivatives and 5-fluorocytosine are useful as germicidal and antineoplastic agents while 5-fluorouracil itself is a known cancer chemotherapy agent.