PURPOSE: To recover 5-fluorouracil useful as a medicine in high purity, by treating a recrystallization mother liquor of concentrated 1-carbamoyl-5-fluorouracil with a small amount of water, and hydrolyzing the treated mother liquor under mild conditions.
CONSTITUTION: A mother liquor containing 1-carbamoyl-5-fluorouracil is concentrated under ordinary or reduced pressure to give an amount of preferably 30% or less, and the resultant recrystallization mother liquor is agitated with NH3 and water at 10W50°C for 2W3hr, and if necessary cooled to 0W30°C to deposit, separate and recover 5-fluorouracil useful as a raw mateial for compounds of the formula (R is aliphatic or aromatic hydrocarbon residue), e.g. 1- hexylcarbamoyl-5-fluorouracil, which is a carcinostatic agent. Aqueous ammonia is preferred as the NH3 and water to be used, and the amount thereof is 0.05W 0.30 that of the concentrated mother liquor for 10W30% aqueous ammonia usable at room temperature.
TANAKA YASUHIKO
ITOU HIROYUKI
