Synthesis of Tetrahydropyrido-and Pyrido-[1',2':1,2]imidazo[4,5-b]pyrazine Derivatives. -Novel polyfluorinated imidazolopyrazine scaffolds (III) and (IX) are obtained in a one-step procedure from tetrafluoropyrazine (I). Their reactions with representative N-and O-nucleophiles are studied. -(PARKS