Heterocyclic polyfluoro-compounds. Part X. Nucleophilic substitution in tetrafluoropyrimidine

Abstract

Tetrafluoropyrimidine, prepared in high yield by reaction of tetrachloropyrimidine with anhydrous potassium fluoride at elevated temperatures, is highly susceptible to attack by nucleophiles; the ease of displacement of ring fluorines decreases in the order 4- and 6- > 2- 5-. Through use of appropriate nucleophilic reagents the following fluoro-pyrimidines have been prepared: 4-X·C₄F₃N₂(X = OH), 4-Y·C₄F₃N₂, and 4,6-Y₂·C₄F₂N₂(Y = NH₂, OMe, NHPh, NHMe, or NMe₂), and 2,4,6-Z₃·C₄FN₂(Z = OMe). The structures of these compounds were established by nuclear magnetic resonance spectroscopy. Interpretation of the orientation of nucleophilic attack on tetrafluoropyrimidine and on pentafluoropyridine is provided.