A new route to the synthesis of 5-fluorouracil

Starting from tetrafluoropyrimidine (1), selective fluorine/ chlorine exchange reactions and selective hydrogenolysis of the chlorine substituents are described. Combination of these methods, together with a subsequent hydrolysis reaction, provides a new route to the synthesis of 5-fluorouracil via 4,6-dichloro-2,5-difluoropyrimidine and 4-chloro-2,5-difluoropyrimidine.