Process for the preparation of 5-(trifluoromethyl)-uracil, and the novel compounds 2,4-dichloro-5-trichloromethyl-pyrimidine and 2,4-difluoro-5-trifluoromethyl-pyrimidine

A process for the preparation of 5-(trifluoromethyl)uracil, comprising:

• a. chlorinating thymine by reacting thymine with phosphorus oxychloride in the presence of a tertiary amine at 20.degree. to 120.degree. C. to yield 2,4-dichloro-5-methylpyrimidine,
• b. chlorinating 2,4-dichloro-5-methylpyrimidine by reacting 2,4-dichloro-5-methylpyrimidine with elemental chlorine or sulphuryl chloride at temperatures of 180.degree. to 250.degree. C., in the presence of radical-forming agents, without using a solvent, and optionally under UV irradiation to yield 2,4-dichloro-5-trichloromethylpyrimidines,
• c. reacting 2,4-dichloro-5-trichloromethylpyrimidine with a catalytic amount of antimony halides and excess hydrogen fluoride or hydrogen fluoride alone to yield 2,4-fluorinated and/or chlorinated 5-trifluoromethylpyrimidine, and
• d. hydrolyzing the 2,4-fluorinated and/or chlorinated 5-trifluoromethylpyrimidines with excess water and in the presence of a fluoride selected from the group consisting of potassium fluoride and sodium fluoride to yield 5-(trifluoromethyl) uracil.