Stabilization of monofunctional platinum-nucleotide adducts: Reactions of N-acetyl-L-methionine complexes with guanosine 5′-monophosphate and guanylyl(3′-5′)guanosine

Abstract

The complexes [Pt(en)(MeCO-Met-S)Cl]NO3 1, [Pt(en)(MeCO-Met-S)2][NO3]2 2 (en = ethane-1,2-diamine, MeCO-Met = N-acetyl-L-methionine) and their 15N analogues (1n and 2n) have been prepared and characterized by 1H, 13C and two-dimensional [1H, 15N] spectroscopy. Complex 1 (half-life 3.9 h at 310 K) hydrolysed more slowly than [Pt(en)Cl2], whereas 2 was stable in water. The reaction of In with guanosine 5′-monophosphate (5′-GMP) gave a stable mixed-ligand complex [Pt([15N]en){MeCO-Met(1 -)-S}(5′-GMP-N7)]+, and the reaction with guanylyl(3′-5′)guanosine (GpG) gave two different monofunctional adducts [Pt([15N]en){MeCO-Met(1 -)-S}(GpG-N7)]+, due to platination of either 3′- or 5′-G, with a prefer..