Synthesis of new benzothiazole derivatives bearing thiadiazole as monoamine oxidase inhibitors

Monoamine oxidases (MAO) are enzymes that catalyze the oxidative deamination of monoamines such as dopamine, noradrenaline, adrenaline, and serotonin. Recent studies have shown that numerous benzothiazole derivatives exhibit hMAO inhibitory activity in the micromolar concentration range. In this study, a novel series of benzothiazole-thiadiazole (5a-5l ) was synthesized and characterized their chemical structures by ¹H-NMR, ¹³C-NMR, and Mass spectroscopy. These compounds were evaluated as inhibitors for types A and B MAO enzymes. Compounds 5f and 5l were the most active derivatives in the series with an IC₅₀ values of 0.107 ± 0.003 and 0.128 ± 0.004, respectively. Furthermore, cytotoxicity of compounds 5f and 5l were investigated and found as non-cytotoxic.     

Monoterpenoid glucoindole alkaloids and iridoids from Pterocephalus pinardii

A new secondary metabolite, pterocephaline, along with the known cantleyoside, 7α‐morroniside, 3β,5α‐tetrahydrodesoxycordifoline lactam, 5S‐5‐carboxyvincoside, sweroside, and loganin have been isolated from the aerial parts of P. pinardii (Dipsacaceae). Moreover, cantleyoside‐methyl‐hemiacetal and cantleyoside‐dimethyl‐acetal were obtained as seco‐iridoid artifacts. The structures were elucidated by extensive spectroscopic methods including 1D‐(¹H, ¹³C and TOCSY) and 2D‐NMR (DQF‐COSY, HSQC and HMBC). Monoterpenoid glucoindole alkaloids were encountered for the first time in Dipsacaceae family. Copyright © 2010 John Wiley & Sons, Ltd.     

Printable optical sensors based on H-bonded supramolecular cholesteric liquid crystal networks

A printable H-bonded cholesteric liquid crystal (CLC) polymer film has been fabricated that, after conversion to a hygroscopic polymer salt film, responds to temperature and humidity by changing its reflection color. Fast-responding humidity sensors have been made in which the reflection color changes between green and yellow depending on the relative humidity. The change in reflection band is a result of a change in helix pitch in the film due to absorption and desorption of water, resulting in swelling/deswelling of the film material. When the polymer salt was saturated with water, a red-reflecting film was obtained that can potentially act as a time/temperature integrator. Finally, the films were printed on a foil, showing the potential application of supramolecular CLC materials as low-cost, printable, battery-free optical sensors.     

Graphene oxide integrated sensor for electrochemical monitoring of mitomycin C-DNA interaction

We present a graphene oxide (GO) integrated disposable electrochemical sensor for the enhanced detection of nucleic acids and the sensitive monitoring of the surface-confined interactions between the anticancer drug mitomycin C (MC) and DNA. Interfacial interactions between immobilized calf thymus double-stranded (dsDNA) and anticancer drug MC were investigated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. Based on three repetitive voltammetric measurements of 120 μg mL(-1) DNA immobilized on GO-modified electrodes, the RSD % (n = 3) was calculated as 10.47% and the detection limit (DL) for dsDNA was found to be 9.06 μg mL(-1). EIS studies revealed that the binding of the drug MC to dsDNA leads to a gradual decrease of its negative charge. As a consequence of this interaction, the negative redox species were allowed to approach the electrode, and thus increase the charge transfer kinetics. On the other hand, DPV studies exploited the decrease of the guanine signal due to drug binding as the basis for specifically probing the biointeraction process between MC and dsDNA.     

Energy and Momentum of Higher Dimensional Black Holes

In this paper, we devote to investigate the energy-momentum problem of higher dimensional black holes in the general theory of relativity. The energy and momentum complex of M?ller has been used for the calculations. Also, total energy and total momentum of some special cases for higher dimensional black holes such as Schwarzschild-like black holes, Reissner-Nordstr?m-like charged black holes, AdS-like black holes, topological black holes, BTZ-like and charged BTZ-like black holes were obtained. It is invented that the momentum of black holes vanishes everywhere while the energy of black holes are not equal to zero in higher dimension. Also the results agree with Yang and Radinschi or Vagenas results in three and four dimensional black holes, respectively (Jang and Radinschi in AIP Conf. Proc. 895, 325, 2007; Vagenas in Mod. Phys. Lett. A 21, 1947, 2006).     

Comparison of some newly synthesized chemically modified Amberlite XAD-4 resins for the preconcentration and determination of trace elements by flow injection inductively coupled plasma-mass spectrometry (ICP-MS)

XAD copolymer resins may be functionalized with heavy metal ion-selective ligands either by covalent linkage to the polymer backbone or by impregnation. These resins may be tailored to be specific for certain heavy metals by adjusting the retention and elution parameters. For the synthesis of immobilized Amberlite XAD-4 copolymer resins that are expected to preconcentrate a number of transition and heavy metals, the Schiff base method was chosen. For this purpose the copolymer was nitrated, reduced to the corresponding amine and converted to the imine compounds via a Schiff base reaction using different organic aldehyde compounds. The interactions of 8 elements (Cd, Co, Cu, Mn, Ni, Pb, U and Zn) with the resins were qualitatively investigated. Optimal pH for retention was typically 6-8 for most resins although one could be used at pH 5 and elution was achieved using 0.1 M HNO3. The resins were characterized by FTIR, SEM and elemental analysis. It was demonstrated that the resins could be used to preconcentrate ultra-trace analytes from natural waters, and analysis of environmental certified reference materials using FI-ICP-MS showed good agreement with the certified values. Metal retention capacities were also calculated using a batch system and were found to compare favorably with other resins reported in the literature.     

The Comparison of Electrochemical Assay and Agarose Gel Electrophoresis for the Determination of DNA Damage Induced by Kainic Acid

A possible DNA damage after interaction of kainic acid (KA) with calf thymus double stranded DNA and genomic DNA was herein determined in in vitro and in vivo conditions using; electrochemical assay and agarose gel electrophoresis. The changes in guanine signal were detected as an indicator of DNA damage in genomic DNA samples isolated from 1 or 10 mg/kg KA‐treated animals. The decreased levels of guanine signal were found as 29% and 33% by 1 and 10 mg/kg KA treatment when compared to controls, respectively. The results of gel electrophoresis confirmed DNA damage obtained in identical samples by electrochemical method.     

Synthesis,Characterization, and Biological Evaluation of Some Novel Thiosemicarbazones as Possible Antibacterial and Antioxidant Agents

Abstract

The synthesis and characterization of 18 novel thiosemicarbazones have been investigated as part of a research program on development of compounds with antibacterial and antioxidant activities. Among the tested compounds, 2-(4-hydroxybenzylidene)-N-[4-(trifluoromethoxy)phenyl]hydrazine carbothioamide (3g) and 2-(thiophen-2-ylmethylidene)-N-[4-(morpholin-4-yl)phenyl]hydrazine carbothioamide (4b) showed excellent inhibition potency at low concentration (0.5 μg/mL) against Gram-positive pathogens (Enterococcus faecalis and Staphylococcus aureus). All tested compounds were also found to possess antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]     

Catalyst functional group cooperativity in the amino acid-catalysed nitroaldol condensation reaction

Several amino acids and their derivatives have been evaluated as organic catalysts for the nitroaldol reaction. It was found that when an unprotected amino group and an unprotected carboxylate group were present in the organocatalyst, both the nitroaldol reaction and subsequent elimination could occur to afford nitroalkenes from aromatic aldehydes and nitromethane. The best results were obtained by use of γ-amino acids derived from l-glutamine. It is suggested that the amino group is important for intermediate Schiff base formation and that the free carboxylate group facilitates the elimination step.