Reactions of pentafluoropyridine with guanidine, thiourea and urea with the hope of preparing derivatives which may be cyclised to polyfluorodeazapurines are described The reactions with urea and thiourea produced, somewhat unexpectedly, bis-(2, 3, 5, 6- tetrafluoro-4-pyridyl) amine and bis-(2, 3, 5, 6-tetrafluoro-4-pyridyl) sulfide, respectively, the structure of the amine was confirmed by X-ray crystallography. The product from the ...