Novel and versatile reactions of trifluoroamine oxide: A new route to polyfluorinated ethers

A series of pyrimidine methyl and polyfluoroalkyl ethers were synthesized f rom the reactions of trifluoroamine oxide (1) with several 5-substituted ur acils in the presence of tetrabutylammonium hydroxide and methanol, 2,2,2-t rifluoroethanol (6), or 1 H, 1H-pentafluoropropanol (7). With 5-(trifluorom ethyl)uracil (2), the new ethers formed were 5-fluoro-5-(trifluoromethyl)-6 -methoxypyrimidine-2,4-dione (8), 5-fluoro-5-(trifluoromethyl)-6-(trifluoro ethoxy)pyrimidine-2,4-dione (9), and 5-fluoro-5-(trifluoromethyl)-6-(1H, 1H -pentafluoropropoxy)pyrimidine-2,4dione (10). With 5-chlorouracil(3), the n ew ethers 5-chloro-5-fluoro-6-methoxypyrimidine-2,4-dione (11), 5-chloro-5- fluoro-6-(trifluoroethoxy)pyrimidine-2, (12), and 5-chloro-5-fluoro-6-(1H, 1H-pentafluoropropoxy)pyrimidine-2,4-dione (13) were obtained. With 5-fluor ouracil (4), the new ethers 5,5 difluoro-6-methoxypyrimidine-2,4dione (14), 5,5-difluoro-6-(trifluoroethoxy)pyrimidine (15) and 5,5 difluoro-6-(1H,1H- pentafluoropropoxy)pyrimidine-2,4-dione (16) were found. By reaction of 5-n itrouracil (5), the new ethers 5-nitro-5-fluoro-6 methoxypyrimidine-2,4-dio ne (17), 5-nitro-5-fluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (18), and 5-nitro-5-fluoro-6-(1H, 1H-pentafluoropropoxy)pyrimidine-2,4-dione (19) we re obtained. Each of the new compounds was characterized by using IR,F-19 a nd H-1 NMR, and mass spectroscopy, and elemental analysis. A single-crystal X-ray diffraction study of 8 was helpful in confirming compound structure.