Synthesis of fluorine containing N-heterocycles using oxides of terminal perfluoroolefins and urea

The reaction of octafluoro-1,2-epoxybutane (1) with urea in Me2SO, aqueous Me2SO, aqueous dioxane, aqueous acetonitrile and of hexadecafluoro-1,2-epoxyoctane (2) with urea in aqueous Me2SO gave perfluoroalkylhydantoins – 5-hydroxy-5-pentafluoroethylimidazolidine-2,4-dione (4a) (yield 40–42%) and 5-hydroxy-5-tridecafluorohexylimidazolidine-2,4-dione (4b) (yield 54%), respectively. Use of dioxane and acetonitrile in the reaction of oxiranes 1, 2 with urea led to unexpected heterocyclic products – perfluoroalkyloxazoles 7a, b (yield 11–82%). Perfluoroalkyl containing allantoin – 5-tridecafluorohexyl-5-ureidoimidazolidine-2,4-dione (3b) (yield 19%) and polyfluoroalkyl containing urea–(2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoro-1-hydroxyheptyl)urea (6b) (yield 46%) have been first obtained by the reaction of oxirane 2 with urea in Me2SO and aqueous Me2SO, respectively. lecular and crystal structure of hydantoin 4a has been studied by X-ray crystallography.