Kinetics and mechanism of oxidation of erythro-series pentoses and hexoses by N-chloro-p-toluenesulfonamide

The kinetics and mechanism of oxidation of D-glucose, D-mannose, D-fructose, D-arabinose, and D-ribose with chloramine-T in alkaline medium were studied. The rate law, rate = k Chloramine-T] Sugar] HO-](2), was observed. The rate of the reaction was influenced by a change in ionic strength of the medium, and the dielectric effect was found to be negative. The latter enabled the computation of d(AB), the size of the activated complex. The reaction rate was almost doubled in deuterium oxide. Activation energies were calculated from the Arrhenius plots. HPLC and GLC-MS analyses of the products indicated that the sugars were oxidized to a mixture of aldonic acids, consisting of arabinonic, ribonic, erythronic, and glyceric acids. Based on these data, a plausible mechanism involving the aldo-enolic anions of pentoses and keto-enolic anions of hexoses is suggested. (C) 1998 Elsevier Science Ltd. All rights reserved

Synthesis of 1,2-benzisoxazole tethered 1,2,3-triazoles that exhibit anticancer activity in acute myeloid leukemia cell lines by inhibiting histone deacetylases, and inducing p21 and tubulin acetylation

1,2,3-Triazole-based heterocycles have previously been shown to possess significant anticancer activity in various tumor models. In the present study, we attached a 1,2,3-triazole moiety to the third position of a 1,2-benzisoxazole heterocycle via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) with various alkynes and established for the title compounds significant antiproliferative effect against human acute myeloid leukemia (AML) cells. Among the tested compounds, 3-(4-(4-phenoxyphenyl)-1H-1,2,3-triazol-1-yl)benzodisoxazole (PTB) was found to be the most potent antiproliferative agent with an IC50 of 2 μM against MV4-11 cells using MTT assay. Notably, PTB induced cytotoxicity in MOLM13, MOLM14 and MV4-11 cells with selectivity over normal bone marrow cells (C57BL/6). Furthermore, PTB was found to induce cytotoxicity by increasing apoptosis of AML cells (MOLM13, MOLM14 and MV4-11) as well as sub-G1 cell population and apoptotic cells at submicromolar concentrations, as shown by flow cytometry and Annexin-V staining, respectively. On the protein level we suggested histone deacetylases (HDACs) as the potential protein target of those compounds in silico, and the predicted target was next experimentally validated by measuring the variations in the levels of p21, cyclin D and acetylation of histone H3 and tubulin. Molecular docking analysis of the title compounds with the second deacetylase domain of HDAC6 displayed high degree of shape complementarity to the binding site of the enzyme, forming multiple molecular interactions in the hydrophobic region as well as a hydrogen bond to the phenol side-chain of Tyr-782. Thus, 1,2,3-triazole derivatives appear to represent a class of novel, biologically active ligands against histone deacetylases which deserve to be further evaluated in their applications in the cancer field. © 2015 Elsevier Ltd. All rights reserved

Pyrrolidine-based cationic γ-peptide: a DNA-binding molecule works as a potent anti-gene agent

Pyrrolidine-based cationic peptides showing high stability to enzyme degradation and strong binding affinity towards DNA are widely investigated as tools to interfere in gene expression. Several studies have been focused on γ-peptide analogs with modifications on the peptide backbone in the attempt to overcome solubility, uptake, and aggregation issues. Pyrrolidine-based γ-peptide derivatives having two different modes of backbone conformation show interesting properties in terms of secondary structure and affinity of binding towards nucleic acids. In this paper, we illustrate our results obtained on two cationic 8-mer γ-peptides Gp1 and Gp2, and how they differ in side-chain spacing along the backbone was tested for DNA binding and DNA transfection activity. Both γ-peptides are stable toward protease digestion. Gp1 binds to DNA more tightly than GP2. This binding ability of Gp1 is attributed to its characteristic of single-chain PPII-like conformation. The Gp1 shows a reduction in its electrophoretic mobility when treated with plasmid DNA. The DNA transfection ability of γ-peptide Gp1 was compared with commercially available transfection reagent Effectene. In each case, Gp1 significantly enhanced the transfection efficiency (40%) of plasmid in Schneider cells compared to the commercial reagent (18%). The other γ-peptide GP2 is not active

Electrochemical heavy metal detection, photocatalytic, photoluminescence, biodiesel production and antibacterial activities of Ag�ZnO nanomaterial

Zinc oxide nanoparticles (ZnO Nps) and silver doped zinc oxide nanoparticles (Ag�ZnO Nps) were prepared using nitrates of zinc and silver as oxidizers and succinic acid as a fuel through solution combustion synthesis (SCS) at 400 °C. The synthesized materials were characterized by various analytical techniques such as XRD, FTIR, Raman UV�vis, PL, SEM, EDX and TEM. The synthesized nanomaterials were tested for the photocatalytic degradation of methylene blue and the result reveal that Ag�ZnO Nps shows the better photocatalytic activity compared to undoped ZnO Nps. Biodiesel production from Simarouba oil shows that Ag�ZnO Nps acts as good catalyst compare to ZnO Nps, we have also developed sensor which showed a linearity in the concentration range 50�350 nM and limit of detection was found to be 3.5 and 3.8 nM (3�) for lead and cadmium respectively. Further we have examined the antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. © 2017 Elsevier Lt

Novel ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate derivatives: synthesis and anticancer activities

To explore the anticancer activity of 2, 4, 5, 6-substituted pyrimidines, several ethyl 2-(1-aminocyclobutyl)-5-(benzoyloxy)-6-hydroxy-pyrimidine-4-carboxylate derivatives associated with the different substituted aromatic/aliphatic carboxamides and sulfonamides were synthesized. Different groups and position on phenyl ring attached to the carboxamide and sulfonamide of the pyrimidine led to two set of compounds. Their chemical structures were confirmed by IR,1H NMR and LC/MS analysis. Cytotoxicity of all the synthesized compounds were examined on human leukemia celllines (K562 and CEM). The preliminary results showed most of the derivatives exhibited good antitumor activity. Compound with para chloro substitution among carboxamides and compound with meta dichloro substitution among sulphonamidesexhibited significant antitumor activity with IC50 value of 14.0 μM and 15.0 μM respectively against K562cell line. For comparison among electron donating groups between carboxamides and sulfonamides, compounds with para tert-butyl substitution were chosen for further studies. Cell cycle analysis suggests that both tert-butyl substituted compounds are able to induce apoptosis

Synthesis and antiproliferative activity of novel homopiperazine derivatives in leukemia cells

A series of novel homopiperazine derivatives were synthesized and characterized using 1H NMR, LC MS, IR and elemental analysis data. These novel molecules were evaluated for their antiproliferative activity against Reh, leukemia cells using trypan blue and MTT assays. All the molecules showed cytotoxicity with IC50 values between 50-100 μM as calculated by trypan blue assay and greater than 100 μM as calculated by MTT assay. Compound 6b with 3,5-dinitro substituents on phenyl ring of the aryl carboxamide moiety attached to homopiperazine ring showed good activity with IC50 value of 41 μM

Kinetics and mechanism of oxidation of ɑ-phenylbenzenemethanols by sodium-N-bromo-p-toluenesulphonamide catalysed by ruthenium(III)

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Oxidation of erythrose series sugars by sodium N-chlorobenzenesulphonamide in alkaline medium: A kinetic study

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Anticancer Functions of Pyridine Heterocycles

Pyridine is a heterocyclic molecule with a nitrogen atom that is often found in nature. As a prosthetic group taking part in redox processes in the biological system, it plays an important function in many enzymes of the living system. Pyridine is an important pharmacophore, a privileged scaffold, and a superior heterocyclic system in drug development, with various applications in anticancer research because of its ability to work on significant receptors. Typically, it is the core of several currently available medicines. In the fight against cancer, many pyridine derivatives have been shown to inhibit kinases, androgen receptors, tubulin polymerization, topoisomerase enzyme, human carbonic anhydrase, and several other targets. Researchers are now concentrating on developing pyridine novel entities with other moieties for cancer therapy. This section presents pyridine derivative synthesis and biological expansions, as well as their target receptor sites