A series of 5-fluoro-6-substituted-5, 6-dihydrouracil-5-carboxylic esters (13), -5-carboxamides (15, 16), and -5-carbonitriles (18, 19) was prepared by direct fluorination of the corresponding uracil-5-carboxylic esters (6), -5-carboxamide (14), and -5-carbonitrile (17) with fluorine or trifluoromethyl hypofluorite (CF₃OF) in the presence of water, methanol and/or acetic acid. Hydrolysis of the above-mentioned products under mild conditions gave 5-fluorouracil (1a) in high yield. Some applications of the present method for the synthesis of 1-(2-tetrahydrofuryl)-5-fluorouracil (1b) were also described.