Synthesis of N-polyfluorinated alkyl derivatives of uracil and 5-substituted uracils: X-ray structure of a mono N-substituted 5-trifluoromethyluracil

The treatment of uracil (A), 5-trifluoromethyluracil (B), 5-chlorouracil (C), 5-fluorouracil (D), and 5-nitrouracil (E) with 1-iodo-1H, 1H,2H,2H-perfluorooctane (F) in the presence of sodium carbonate gave the corresponding 1,3-di(1H,1H,2H,2H-perfluorooctyl)uracil (1), 1,3-di(1H,1H,2H,2H-perfluorooctyl)-5-trifluoromethyluracil (3), 1,3-di(1H,1H,2H,2H-perfluorooctyl)-5-chlorouracil (5), 1,3-di(1H,1H,2H,2H-perfluorooctyl)-5-fluorouracil (7) and 1,3-di(1H,1H,2H,2H-perfluorooctyl)-5-nitrouracil (9) in reasonably good yields. In analogous reactions, 4-iodo-2-(trifluoromethyl)-1,1,1,2-tetrafluorobutane (G) reacted smoothly with A–E to form the respective 1,3-disubstituted derivatives 2, 4, 6, 8 and 10 in moderate yields. The structure of the only mono-substituted product isolated from this series of reactions, in this case between B and F to give 1-mono(1H,1H,2H,2H-perfluorooctyl)-5-trifluoromethyluracil (11), was determined from X-ray diffraction studies. The compounds were characterized by using IR, and 1H and 19F NMR spectroscopy, and MS and HRMS.