Complexes of inosine, cytidine, and guanosine with palladium(II)

Abstract

The reactions of Pd(II) with inosine (InoH) and guanosine (GuoH) have been studied in aqueous solutions. The complexes isolated from these reactions have the following formulas: cisand trans-[Pd(NuclH)2Cl2], cisand Zrons-[Pd(Nucl)2], cisand trozis-[Pd(InoH)2(NuclH)2]Cl2, cisand irons-[Pd(GuoH) 2(NuclH)2]Cl2, cis-[Pd(H2G)2(GuoH)2]Cl2, cis-[Pd(GuoH)?(Guo)]Cl, ds-[Pd(GuoH)2(Ino)]Cl, [Pd(GuoH)3Cl]Cl, and [Pd(GuoH)2(InoH)Cl]Cl, where NuclH = inosine and guanosine. The compounds have been identified by elemental analyses, conductivity measurements, and IR and NMR spectra. In this case, i.e., with palladium, both cis and trans isomers have been isolated and characterized, in contrast to the platinum analogues. The diaquo cis-[Pd(H20)2(GuoH)2]Cl2 complex and the trinucleosides, [Pd(GuoH)3Cl]Cl and [Pd(GuoH)2(InoH)Cl] Cl, are ionic and novel in this series of complexes. The trans effect of nucleosides follows the order Nucl < Cl™, Br". N706 chelation has been found here, comparable to that proposed for the analogous platinum complexes. This N706 chelation is discussed with relation to the mode of action and the antitumor activity of ris-[Pt(NH3)2Cl2].

Synthesis, Characterization and Antiviral Properties of Pd(II) Complexes With Penciclovir

“…spectra of the complexes showed a strong band invariably at 1697 to 1726 cm q assigned to free _(C=O) of the 6 th position of the purine ring or the 3 t position of the pyrimidine ring, in the case of cyd containing complexes, excluding the formation of a Pd-O bond through the carbonyl group or the coordination through the neighboring N1. A similar behavior was observed in the infrared spectra of trans-and cis-(nucl)2PdCl or mixed trans-or c__is-[(nucl)2Pd(nucl')2]Cl2, were nucl or nucl_ guanosine, inosine or cytidine [12,13]. In addition all spectra of the prepared complexes, exhibited a broad band at about 425 to 430 cm q, attributed to Pd-N stretching vibration, suggesting coordination through N7.…”

“…The nucleosides guanosine, inosine, cytidine were purchased from Sigma and used without further purification. Palladium(II) chloride was obtained from Fluka A.G. Penciclovir [11], and the complexes (guo)2PdCl2, (ino)2PdCl2 and (cyd)2PdCl2 were prepared according to the literature [12]. The i.r.…”

Reactions of the Rhodium Trifluoroacetate Dimer With Nucleosides and Nucleotides

“…These variations, together with the fact that the band due to C=C and C=N ring vibration at 1592 cm-' remains unaltered, point to C(6)=0 c~ordination.~~ Several studies have dealt with the carbonyl group as a possible binding site in complexes with inosine. Small shifts of the v-C=O band shows that this group is not involved in metal co~rdination.~~, 36,643 [74][75][76] On the contrary, considerable shifts to lower frequencies are explained by metallation at this position;73 if at the same time significant changes in the ring bands take place, then bidentate coordination through the O(6) and a ring nitrogen atom is sugge~ted.~', ' *, 64 The bands observed at 1475 and 1427 cm-' attributed to vibrations related with N(7) do not change appreciably on formation of the complex, corroborating the non-involvement of this atom in metal binding.…”

Synthesis, characterization and assessment of the cytotoxic properties of cis and trans-[Pd(L)2Cl2] complexes involving 6-benzylamino-9-isopropylpurine derivatives

“…For that reason, the main interest is paid to Pd(II), mainly due to the evident structural analogy between Pt(II) and Pd(II) complexes. Other derivatives of cis-[Pd(L) 2 Cl 2 ] have been described, where L = pyrazole [21], triazolopyrimidine [22] or inosine derivatives [23], with significant antitumour activity. Many trans-[Pd(L) 2 been published, where L = 2,6-dimethyl-4-nitropyridine [24], pyrazole [21], aminobenzonitrile [25], inosine, guanosine, adenosine, xanthosine [23,26] or 6-benzylaminopurine derivatives [18,27,28], with moderate anticancer properties.…”

“…Other derivatives of cis-[Pd(L) 2 Cl 2 ] have been described, where L = pyrazole [21], triazolopyrimidine [22] or inosine derivatives [23], with significant antitumour activity. Many trans-[Pd(L) 2 been published, where L = 2,6-dimethyl-4-nitropyridine [24], pyrazole [21], aminobenzonitrile [25], inosine, guanosine, adenosine, xanthosine [23,26] or 6-benzylaminopurine derivatives [18,27,28], with moderate anticancer properties. It is known that the mechanism of action of trans-diamminedichloroplatinum(II) (Transplatin) derivatives has been studied and described in greater details [20,29,30] than in case of trans-Pd(II) analogues [24].…”