Quintal Susana M O, Qu Yun, Quiroga Adorácion G, Moniodis Joseph, Nogueira Helena I S, Farrell Nicholas
Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Inorg Chem. 2005 Jul 25;44(15):5247-53. doi: 10.1021/ic050062w.
This paper reports on the chemistry of platinum complexes containing bidentate pyridine-carboxylate (pyAc = pyridin-2-yl-acetate and picEt = pyridine-2-ethylcarboxylate, ethylpicolinate) (N,O) ligands. The pyridine-2-acetate and ethylpicolinate ligands form six- and five-membered chelates, respectively, upon formation of the Pt-carboxylate bond. In all reactions with picEt with various platinum complex starting materials, spontaneous de-esterification of the pendant carboxylate ester occurs to give directly the chelates K[PtCl(2)(pic-N,O)]-trans-[Pt(pic-N,O)(2)] and SP-4,2-[PtCl(pic-N,O)(NH(3))] without any evidence of intermediates. The de-esterification is solvent dependent, and molecular modeling was used to explain this reaction. The reactions of the geometric isomers of [PtCl(pyAc-N,O)(NH(3))] with 5'-guanosine monophosphate, 5'-GMP, and N-acetyl-l-methionine, AcMet, were investigated by NMR spectroscopy. The objective was to ascertain by model chemistry the feasibility of formation of ternary DNA-Pt-protein adducts in biology. Model nucleotide and peptide compounds were formed in situ by chloride displacement giving PtL(pyAc-N,O)(NH(3)) (L = 5'-GMP or AcMet). Competitive reactions were then examined by addition of the complementary ligand L. Sulfur displacement of coordinated 5'-GMP was slow. For SP-4,3-Pt(AcMet)(NH(3))(PyAc-N,O), a rapid displacement of the sulfur ligand by 5'-GMP was observed, giving SP-4,2-Pt(5'-GMP-N7)(pyAc-N,O)(NH(3)).
本文报道了含双齿吡啶 - 羧酸盐（pyAc = 吡啶 - 2 - 基 - 乙酸酯和picEt = 吡啶 - 2 - 乙基羧酸盐，乙基吡啶羧酸酯）（N，O）配体的铂配合物的化学性质。吡啶 - 2 - 乙酸酯和乙基吡啶羧酸酯配体在形成Pt - 羧酸盐键时分别形成六元环和五元环螯合物。在picEt与各种铂配合物起始原料的所有反应中， pendant羧酸酯会自发脱酯，直接生成螯合物K[PtCl(2)(pic - N,O)] - trans - [Pt(pic - N,O)(2)]和SP - 4,2 - [PtCl(pic - N,O)(NH(3))]，没有任何中间体的迹象。脱酯反应取决于溶剂，并且使用分子模型来解释该反应。通过核磁共振光谱研究了[PtCl(pyAc - N,O)(NH(3))]的几何异构体与5'-鸟苷单磷酸（5'-GMP）和N - 乙酰 - L - 甲硫氨酸（AcMet）的反应。目的是通过模型化学确定在生物学中形成三元DNA - Pt - 蛋白质加合物的可行性。通过氯离子置换原位形成模型核苷酸和肽化合物，得到PtL(pyAc - N,O)(NH(3))（L = 5'-GMP或AcMet）。然后通过加入互补配体L来研究竞争反应。配位的5'-GMP的硫置换反应很慢。对于SP - 4,3 - Pt(AcMet)(NH(3))(PyAc - N,O)，观察到5'-GMP快速置换硫配体，生成SP - 4,2 - Pt(5'-GMP - N7)(pyAc - N,O)(NH(3))。
