The Synthesis of Novel Methotrexate-like Compounds

Summary. Methotrexate (MTX) is a folate antagonist used in treatment of several chronic inflammatory and neoplastic conditions. In this study, new MTX-like compounds that may-be potential anticancer agents were synthesized and their structures were determined by IR, UV, GC-MS, ¹H NMR, and ¹³C NMR spectra. Also, in this study, a series structurally related to MTX or folate analogous compounds were evaluated whether they have inhibitory properties on the dihydrofolate reductase activity (DHFR).     

The Kramer–Mesner method with tactical decompositions: some new unitals on 65 points

We propose a combination of two known computational methods for the construction of designs with prescribed groups of automorphisms: the Kramer–Mesner method and the method of tactical decompositions. This combined method is used to construct new unitals with parameters 2‐(65, 5, 1). © 2011 Wiley Periodicals, Inc. J Combin Designs 19:290‐303, 2011     

Voltammetry as an Alternative Tool for Trace Metal Detection in Peloid Marine Sediments

Here was demonstrated for the first time a possible application of abrasive stripping voltammetry in the direct measurement of trace metals in anoxic, sulfidic marine sediments (peloid mud) from a small and shallow (0.2–1 m) marine lagoon in Central Dalmatia, Croatia. Trace amounts of sample compounds are transferred to the graphite electrode surface and electrochemical reduction or oxidation processes are followed by the cyclic voltammetry in seawater or 0.55 M NaCl as electrolyte. After a preelectrolysis at potentials ranging from ?1.0 to ?1.5 V (vs. SCE) a well‐defined anodic stripping peak corresponding to the oxidation of metal deposits generated at deposition potentials is obtained around ?0.74 V (vs. SCE). The same samples were studied by anodic stripping voltammetry at the Hg electrode and inductively coupled plasma‐mass spectrometer (ICP‐MS). ICP‐MS showed higher concentrations of trace metals such as Al, Fe, Mo, Mn. A relatively high concentration of reduced sulfur species (RSS) (10^?3 M) is determined electrochemically in porewater of the peloid mud, indicating that the magnitude of metal enrichment in the sediments is probably controlled by precipitation with sulfide.     

Synthesis,characterization, antioxidant,antimicrobial and DNA binding properties of ruthenium(II), cobalt(II) and nickel(II) complexes of Schiff base containing o-vanillin

Research on Chemical Intermediates - In this study, the complex combinations of Ru(II), Co(II) and Ni(II) with Schiff base obtained through the condensation of (E)-methyl...     

Characterization of Iron Sulfide Species in Model Solutions by Cyclic Voltammetry. Revisiting an Old Problem

A long‐standing problem associated with voltammetric determination of iron and sulfide in reduced natural waters has been the nature of the presumed analyte responsible for a reduction peak at ?1.1 V vs. Ag/AgCl. Cyclic voltammetry at the Hg electrode is used here to study solutions with different Fe(II) to sulfide ratios in chloride and acetate electrolytes (pH 6–7). The results indicate that the ?1.1 V peak can be assigned to reduction of Fe²⁺ or its labile complexes on FeS layers that partially cover the Hg electrode. Hg electrodes covered with FeS act like FeS solid electrodes over a very wide potential range (?0.35 to ?1.9 V). Two mechanisms for forming FeS layers on Hg are described. Over the broadest deposition potential range, the dominant mechanism involves attachment at the Hg surface of FeS nanoparticles, which are generated quickly in initially supersaturated mixtures of Fe(II) and S(–II). In a narrow deposition potential range, roughly ?0.56 to ?0.70, FeS layers are produced additionally by replacement of preformed HgS. Because Fe²⁺ is reduced at ?1.1 V on FeS layers and at ?1.4 V on bare Hg, it may be underdetermined when only the ?1.4 V peak is measured.     

Synthesis,Spectroscopic Studies and Crystal Structure of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis((thiophene-2-carboxamido)propyl)piperazine

Abstract  A new multidentate ligand N,N′-bis((thiophene-2-carboxamide)propyl)piperazine has been synthesized from the reaction of thiophene-2-carbonylchloride and 1,4-bis(3-aminopropyl)piperazine. The title compound has been characterized by elemental analysis, FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. The crystal structure of the title compound (C₂₀H₃₀N₄O₂S₂Cl₂) has also been determined by X-ray analysis. The title compound crystallize in the monoclinic space group P2₁/c with a = 9.768(1), b = 12.895(1), c = 10.083(1) ?, β = 115.12(1)°, V = 1149.9(2) ?³, D _x = 1.425 g cm⁻³ and Z = 2. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R = 0.039 [I > 2σ (I)] for 2,786 observed reflections. Graphical Abstract  The (N,N’–bis((thiophene-2- carboxamido)propyl)piperazine) molecule has been synthesized and its molecule structure has been investigated by using , FT-IR, 13C NMR and 1H-NMR spectroscopic and crystallographic techniques.

Synthesis,structural characterization and biological activities of metal(II) complexes with Schiff bases derived from 5-bromosalicylaldehyde: Ru(II) complexes transfer hydrogenation

In this study, two novel Schiff base ligands (L¹ and L²) derived from condensation of methyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate and methyl 2-amino-6-phenyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate, both starting matter with 5-bromo-salicylaldehyde, and their Zn(II) and Ni(II) metal complexes have been prepared using a molar ratio of ligand:metal as 1:1 except the Ru(II) complexes 1:0.5. The structures of the obtained ligands and their metal complexes were characterized by elemental analysis, FT-IR, ¹H NMR, ¹³C NMR, UV–vis, thermal analysis methods, mass spectrometry, and magnetic susceptibility measurements. Antioxidant and antiradical activity of Schiff base ligands and their metal complexes were been evaluated in vitro tests. Antioxidant activities of metal complexes generally were more effectives than free Schiff bases. 1c and 2c were used as catalysts for the transfer hydrogenation (TH) of ketones. 1c, 2c complexes were found to be efficient catalyst for transfer hydrogenation reactions.