Platinum(II) Complexes of Purine and Pyrimidine Bases and Their Nucleosides

Stetsenko, A. I.; Yakovlev, K. I.; D'yachenko, S. A.

doi:10.1070/rc1987v056n09abeh003311

Cited by 11 publications

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“…Figure 1 shows the structure of the platinum compounds used. Platinum compounds were obtained by procedures described in [ 15 , 16 , 17 , 23 , 24 , 25 ].…”

Section: Methodsmentioning

confidence: 99%

“…Since the discovery of the anti-tumor activity of cisplatin (cis-DDP) [ 8 , 9 ], only a very few other platinum compounds were introduced into clinical practice [ 10 , 11 , 12 ]. It is known that the activity of platinum compounds may be improved by the introduction of heterocyclic ligands containing N donor atoms [ 13 , 14 , 15 , 16 , 17 ]. For example, tetrazole [ 18 , 19 ] and pyrazine [ 20 , 21 ] are used as ligands for coordination compounds.…”

Section: Introductionmentioning

confidence: 99%

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DNA Conformational Changes Induced by Its Interaction with Binuclear Platinum Complexes in Solution Indicate the Molecular Mechanism of Platinum Binding

et al. 2022

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Platinum anticancer drugs inhibit the division of cancer cells through a DNA binding mechanism. The bimetallic platinum compounds have a possibility for blocking DNA replication via the cross-linking of DNA functional groups at different distances. Many compounds with metals of the platinum group have been tested for possible antitumor activity. The main target of their biological action is a DNA molecule. A combined approach to the study of the interaction of DNA with biologically active compounds of this type is proposed. The capabilities of various methods (hydrodynamic, spectral, microscopy) in obtaining information on the type of binding of coordination compounds to DNA are compared. The analysis of DNA binding with platinum binuclear compounds containing pyrazine, tetrazole, 5- methyltetrazole, 3-propanediamine as bridging ligands in a solution was carried out with the methods of circular dichroism (CD), luminescent spectroscopy (LS), low gradient viscometry (LGV), flow birefringence (FB) and atomic force microscopy (AFM). The competitive binding of different platinum compounds to DNA and the analysis of platinum attachment to DNA after protonation of its nitrogen bases simply indicates the involvement of N7 guanine in binding. Fluorescent dye DAPI was also used to recognize the location of platinum compounds in DNA grooves. DNA conformational changes recorded by variations in persistent length, polyelectrolyte swelling, DNA secondary structure, and its stability clarify the molecular mechanism of the biological activity of platinum compounds.

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“…Figure 1 shows the structure of the platinum compounds used. Platinum compounds were obtained by procedures described in [ 15 , 16 , 17 , 23 , 24 , 25 ].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DNA Conformational Changes Induced by Its Interaction with Binuclear Platinum Complexes in Solution Indicate the Molecular Mechanism of Platinum Binding

et al. 2022

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“…and, in particular, by the structure of the metal-ligand coordination site (fragment or functional group of a biological system) [1]. The Pd(II) complexes with organic ligands are considered to be promising in the production of medicines [2].While studying reactions of the Pd 2+ ion with bioligands, one should take into consideration its interaction with inorganic compounds contained in liquid media of a living organism. It is not improbable that inorganic ligands (H 2 O , Cl -, etc.)…”

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confidence: 99%

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confidence: 99%

Ligand Exchange in Pd(II)-NaCl-H2O and Pd(II)-HCl-H2O Systems: Quantum-Chemical Consideration

2005

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The Pd-containing compounds exhibit the biological activity. The variety of the biological properties of the Pd ions and of another platinum-group metals is determined by the chemical and stereochemical properties of coordination compounds of these metals with the biologically active ligands (DNA, amino acids, peptides, etc.) and, in particular, by the structure of the metal-ligand coordination site (fragment or functional group of a biological system) [1]. The Pd(II) complexes with organic ligands are considered to be promising in the production of medicines [2].While studying reactions of the Pd 2+ ion with bioligands, one should take into consideration its interaction with inorganic compounds contained in liquid media of a living organism. It is not improbable that inorganic ligands (H 2 O , Cl -, etc.) can compete with the biologically active ligands for the metal ion and thus reduce toxicity of the latter ion. On the other hand, binding of the metal cation with inorganic ligands can decrease the efficiency of medicines prepared from compounds of this metal. The Pd(II) complexes are known to be bonded by the DNA molecules and to violate ordinary course of the replication process (transcription and translation) [1]. The Pd ( II )-NaCl -H 2 O and Pd ( II )-HCl -H 2 O systems can be used to model the behavior of the Pd(II) compounds in biological liquids. For instance, a 0.86% (0.147 M) solution of NaCl can be used as a model of blood plasma, while a 0.1 M solution of HCl, as that of a gastric juice [3]. The aim of this work was to study the reactions of exchange of the H 2 O and H 3 O + ligands for Cl -in the chloride and hydrogen chloride solutions of Pd(II). EXPERIMENTAL Potassium tetrachloropalladate(II) was synthesized as described in [4] from metallic Pd and Pd ë l 2 . The K 2 [ PdCl 4 ] (0.03067 M) and NaCl (0.1 M) solutions were prepared from the precisely weighed samples; a 0.1 M solution of HCl was prepared from a reagent with fixed concentration.The kinetic studies were carried out using spectrophotometric method. The electronic absorption spectra of the reaction mixtures were recorded on a UV VIS SPECORD spectrophotometer. The working solution of K 2 [ PdCl 4 ] with a concentration of 8.496 × 10 -5 mol/l was prepared by dilution. The initial solution of K 2 [ PdCl 4 ] (3.610 ml) and the solution of 0.1 M NaCl or HCl (20 µ l) were pored into a cell (1 cm) with the aid of a dispenser.The quantum-chemical calculations were performed by ZINDO/1 [5], PM3 [6], and RHF/STO-6G(d) [7] methods with the HyperChem 1 program package and full optimization using the Polak-Ribiere algorithm [8]. The gradient rate did not exceed 0.02 kcal/(mol Å).Abstract -The behavior of potassium tetrachloropalladate(II) in media simulating biological liquids is studied. The rate of aquation in aqueous NaCl solutions is shown to be higher than the rate at which the Cl -ligand enters the inner coordination sphere of the Pd atom. In HCl solutions, the formation of the Pd chloro complexes predominates due to protonation of water molec...

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“…Palladium(II) complexes with organic ligands are promising as medicines [1] that interact with functional groups of biological systems to give the corresponding coordination entities [2]. In the study of reactions of the palladium ion with bioligands, its interactions with inorganic compounds contained in an organism's fluids should also be considered.…”

mentioning

confidence: 99%

Tautomerism and Regioselectivity of the Protonation of 2-Pyrrolidone. Stereoselectivity of Complexation between Palladium(II), Chloride Ion, and 2-Pyrrolidone

2005

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Palladium(II) complexes with organic ligands are promising as medicines [1] that interact with functional groups of biological systems to give the corresponding coordination entities [2]. In the study of reactions of the palladium ion with bioligands, its interactions with inorganic compounds contained in an organism's fluids should also be considered. It is not improbable that inorganic ligands (H 2 O , Cl -, etc.) competing with biologically active substances for the metal ion can reduce its toxicity. On the other hand, coordination of inorganic ligands by the metal cation can diminish the efficiency of palladium-based medicines; for this reason, mixed-ligand complexes of palladium(II), in which the opposite trends are more or less counterbalanced, are acceptable as medicines.It is expedient to use the chloride ion as an inorganic ligand since it is contained in biological fluids. For instance, blood plasma is simulated by 0.86% (0.147 mol/l) NaCl, while the gastric juice is simulated by 0.1 M HCl [3].2-Pyrrolidone (2-pyrrolidinone, pyrrolidine-2-one, 2-oxopyrrolidine, and γ -butyrolactam) is a promising ligand for the formation of biologically active complexes with platinum metal cations [4]; 2-pyrrolidone can exhibit lactam-lactim tautomerism [5,6]. In sufficiently acidic media, protonation of 2-pyrrolidone (which is possible both at the N and O atoms) can compete with its coordination by metal cations. In[7], dichlorobis(pyrrolin-2-ol)palladium [Pd ( C 4 H 7 NO ) 4 Cl 2 ] was synthesized by the reaction of palladium(II) chloride with 2-pyrrolidone in aqueous acetone and its crystal and molecular structures were determined by X-ray diffraction analysis [8]. The structure consists of an electrically neutral complex and two 2-pyrrolidone molecules attached to it by intermolecular éç ··· é hydrogen bonds [8]. The most important features of the complexation is the lactim (pyrroline-2-ol) structure of the organic ligand, N-coordination, and the cis -structure of dichlorobis(pyrroline-2-ol)palladium [8].Usually, complexation reactions yield trans -isomeric products [9, 10]. However, it is cis -isomers that are of interest as potential antitumor preparations. For this reason, it is important to explain the stereoselectivity of complexation.The goal of this study was to calculate, by quantumchemical methods, the tautomerism and regioselectivity of the protonation of 2-pyrrolidone in the gas phase and an aqueous solution and to justify the stereoselectivity of the complexation between palladium(II), chloride ion, and pyrroline-2-ol. EXPERIMENTALQuantum-chemical calculations for the gas phase were performed by the AM1 [11] and PM3 methods Abstract -According to the AM1, PM3, HF/6-31G(d,p), and MP2/6-31G(d,p)//HF/6-31G(d,p) calculations, it is the lactam tautomer of 2-pyrrolidone that is thermodynamically most stable in both the gas phase and an aqueous solution. Analysis of the PM3 data with consideration of the medium showed that the tautomeric equilibrium of 2-pyrrolidone (pyrroline-2-ol) in aqueous solution is shift...

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Platinum(II) Complexes of Purine and Pyrimidine Bases and Their Nucleosides

Cited by 11 publications

References 6 publications

DNA Conformational Changes Induced by Its Interaction with Binuclear Platinum Complexes in Solution Indicate the Molecular Mechanism of Platinum Binding

DNA Conformational Changes Induced by Its Interaction with Binuclear Platinum Complexes in Solution Indicate the Molecular Mechanism of Platinum Binding

Ligand Exchange in Pd(II)-NaCl-H2O and Pd(II)-HCl-H2O Systems: Quantum-Chemical Consideration

Tautomerism and Regioselectivity of the Protonation of 2-Pyrrolidone. Stereoselectivity of Complexation between Palladium(II), Chloride Ion, and 2-Pyrrolidone

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