Water → 5-Fluorouracil

Participants

Reaction Conditions

Reaction Steps

Into a "Daiflon" resin (polytriflurochloroethylene manufactured by Daikin Kogyo, Co., Ltd.) made flask equipped with a stirrer, a cooler, a gas inlet and a therometer, a solution of cytosine (1.11 g; 10 mmol) in water (50 ml) was charged, and fluorine gas (34%; diluted with nitrogen) was blown therein at 18° to 20° C. until the cytosine was consumed completely. The reaction was finished in 60 minutes, and the total amount of fluorine used was 35 mmol. The reaction mixture (pH, <1) was adjusted to pH 6.0 with an aqueous solution of sodium hydroxide and heated at 80° C. for 4 hours. After removal of the solvent while heating under reduced pressure, the residual pale brown solid was extracted with ethanol and recrystallized from water to give 5-fluorouracil (0.85 g). Yield, 65%. M.P. 282°-283° C. (decomp.). UV absorption spectrum: λmaxpH 2 266 nm; λmaxpH 10.5 269 nm. Thin layer chromatography: Rf 0.60. Paper chromatography: Rf 0.54.

Provenance & Evidence