Metal complexes of biologically important ligands, CXVI. Addition of carbanions from barbituric acid derivatives to unsaturated hydrocarbons in cationic complexes for the organometallic labelling of barbituric acid

摘要

The addition of the anion of 1,3,5-trimethyl-2-thiobarbituric acid 1 to #pi#-bonded unsaturated hydrocarbons (olefin, cyclohexadienyl, cycloheptadienyl, cycloheptatrienyl) in cationic complexes of rhenium, iron, ruthenium and chromium provides a method for the introduction of organometallic fragments into the barbituric acid moiety. Substitution of the C-5-hydrogen atom gives the complexes 4-9. The dianions of 1,3-dimethylbarbituric acid 2 and 1,3-dimethyl-2-thiobarbituric acid 3 yield the bimetallic complexes 10-15. The structures of 10, 11 and 13 were determined by X-ray diffraction. Due to the protection of the N-atom there was no self-assembly via hydrogen bonds. The complexes may be useful as covalent markers for barbiturate drugs in carbonyl metalloimmunoassays.