A series of (0-and p-nitrobenzyloxycarbnyl)-5-fluorouracil derivatives were synthesized by reacting o-or p-nitrobenzyl chloroformate with 5-fluorouracil in the presence of triethylamine in DMF or Me2S0. The reductive activation of these agents was hypothesized to generate a reactive methide and &fluorouracil, two components that are capable of synergistic interaction through complementary inhibition. Measurement of the surviving fractions of ...