Electrophilic addition to the multiple bond of 1-carboxymethyl-5-fluorouracil

1-Carboxymethyl-5-fluoro-5-halogeno-6-hydroxy-5,6-dihydrouracils and 1-carboxymethyl- 5-fluoro-6-hydroxy-5-nitro-5,6-dihydrouracil were synthesized in high yields by oxidative halogenation or nitration of 1-carboxymethyl-5-fluorouracil. Oxidative halogenation or nitration of 5-fluoro-1-(methoxycarbonylmethyl)uracil in acidic media results in the addition of the corresponding groups at the C(5) atom of uracil and simultaneous hydrolysis of the ester group. Bimolecular ions of the obtained compounds were detected in the negative ion mass spectra.