PHOTOCHEMICAL-REACTION OF (ETA(5)-CYCLOPENTADIENYL) DICARBONYLIRON IODIDE WITH 1-SUBSTITUTED URACILS IN THE PRESENCE OF DIISOPROPYLAMINE - CRYSTAL-STRUCTURE OF THE (ETA(5)-C5H5)FE(CO)(2) COMPLEX OF DEPROTONATED 5-FLUORO-1-(TETRAHYDRO-2-FURYL)URACIL(FTORAFUR)

Irradiation with visible light of a mixture of Fe(Cp)(CO)(2)I (Cp = et a(5)-cyclopentadienyl) with 1-methyluracil (1a), 5-fluoro-1-(tetrahydr o-2-furyl)uracil (Ftorafur) (1b) or 6-azauridine-2'3'5'-triacetate (1c ) in the presence of diisopropylamine affords complexes in which the F e(Cp)(CO)(2) moiety is bound to the deprotonated N(3) atom of the urac il moiety. The crystal structure of 2b, made from 1b, was determined a nd is compared with the known structures of the alpha(A), alpha(B) and beta forms of Ftorafur and that of its eta(1)-Au complex. Complex 2b shows the shortest intramolecular C-H...O hydrogen bond between the te trahydrofuran and uracil rings. The stereochemistry of this complex is also discussed.