Efstathios Gavrielatos

Cationic diamineplatinum(II) complexes containing the enolate of N, 3-acetyl-4-hydroxypyrrolin-2-one

Abstract Reactions of cis -(NH 3 ) 2 PtCl 2 , (en)PtCl 2 , (dach)PtCl 2 , K 2 PtCl 4 and the biological active molecule Hata ( N ,3-acetyl-4-hydroxypyrrolin-2-one) have been studied. The species that were formed involve the enolate of Hata in which this moiety acts as a chelating ligand. The isolated complexes have been characterized by elemental analysis, molar conductivity measurements, IR, 1 H NMR and ESI-MS spectroscopy.

Palladium(II)/β-diketonate complexes containing the enolates of N-acetyl-3-acyltetramic acids: Crystal structure of the Lewis base adduct, [Pd(py)4](abta)2

Progressive displacement of acac from [Pd(acac)2] occurs on reaction with different tetramic acids (HL � /Hata, Habta) to give [Pd(acac)(h 2 -L)] and [Pd(h 2 -L)2] but, when HL� /Haceta, only [Pd(acac)(h 2 -L)] is formed, even when the ratio of Pd � /HL is 1:4; reaction of all these tetramic acids with an aqueous solution of K2[PdCl4 ]g ives [Pd(h 2 -L)2]. In solution, NMR studies in non polar solvents show that there is only one isomer of [Pd(acac)(h 2 -L)] whereas there are usually two isomers of [Pd(h 2 -L)2] which are probably due to the presence of cis - and trans -isomers of the complex as a result of both the enolate ligands adopting a O,O?-mode of coordination via the functionalities associated with C 4 and the acyl group at C 3 in the pyrrolidine ring. In pyridine solution, [Pd(h 2 -abta)2] forms a Lewis base adduct, [Pd(py)4](abta)2, which has been characterised by X-ray analysis and shown to contain a

Synthesis of N‐Urethane‐Protected γ‐Amino‐Functionalized Butenoates and Tautomeric Studies by Means of NMR, X‐ray Crystallography and ab initio Calculations

N-Urethane-protected γ-amino-α-cyano-β-hydroxybutenoates were synthesized as potential statine analogues and the stability of their possible tautomers was assessed using NMR, X-ray crystallography and ab initio calculations. The results establish that the cis-enol tautomeric form is the most stable one both in solution (CDCl3) and in the solid phase. In full agreement with the experimental data, the theoretical calculations predicted that the cis-enol tautomer would be the minimum energy tautomer.