POLYFLUORO-HETEROCYCLIC COMPOUNDS .12. PREPARATION AND NUCLEOPHILIC SUBSTITUTION OF TETRAFLUOROPYRIDAZINE

The known method of preparing perfluoro-aromatic nitrogen heterocyclic compounds from their perchloro-analogues by exchange with potassium fluoride in the absence of solvent has been extended to the pyridazine system. Tetrafluoropyridazine readily undergoes nucleophilic substitution of all the fluorine atoms, those at positions 4 and 5 being the most reactive. These reactions have been illustrated using various nucleophilic reagents in which the attacking atoms are nitrogen, oxygen, or sulphur. The factors affecting the orientation and reactivity of tetrafluoropyridazine, and of related perfluoro-aromatic nitrogen heterocyclic compounds, in nucleophilic substitution have been discussed.