PEG-SO3H as a new, highly efficient and homogeneous polymeric catalyst for the synthesis of bis(indolyl)methanes and 4,4��-(arylmethylene)-bis(3-methyl-1-phenyl-1Hpyrazol-5-ol)s in water

In this work, a green, simple and highly efficient procedure for the synthesis of bis(indolyl)methanes and 4,4??- (arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s [as an important class of bis(pyrazolyl)methanes] is described. The condensation of indoles or 1-phenyl-3-methylpyrazol-5-one with carbonyl compounds catalyzed by poly(ethylene glycol)-bound sulfonic acid (PEG-SO₃H) in water affords the title compounds in high yields and relatively short reaction times.     

A comparison of the electrochemical and electroanalytical behavior of ascorbic acid,dopamine and uric acid at bare,activated and multi-wall carbon nanotubes modified glassy carbon electrodes

The electrochemical oxidation of ascorbic acid (AA), dopamine (DA) and uric acid (UA), as three important biological molecules, have been studied at the bare, activated and multi-wall carbon nanotubes modified glassy carbon electrodes (MWCNTGCE) using different voltammetric methods. MWCNT-GCE not only exhibited both the roles of mediator and promoter for AA oxidation, but also performed the role of an excellent promoter for electrochemical oxidation of DA and UA when compared with bare GCE (BGCE) or activated GCE (AGCE). The results show that the oxidation of AA at MWCNT-GCE exhibits the characteristic shape typical of an EC catalytic (E_rC_i ^'anism. In differential pulse voltammetric measurements, MWCNTGCE and AGCE could separate the oxidation peak potentials of AA, DA and UA present in the same solution, though the MWCNT-GCE remarkably improves the sensitivity of determination of the analytes and also reduces the fouling effects as compared to AGCE. Furthermore, the hydrodynamic amperometry at rotating MWCNT-GCE at constant potential was used for determination of AA, DA and UA individually in the presence of the other two species. It has been shown that using MWCNTGCE, these three species can be determined by amperometry with high sensitivity and selectivity. Finally, MWCNT-GCE has been applied to simultaneous determination of AA and DA in the related injection solutions and UA in a human urine sample with satisfactory results.     

Rapid green synthesis of gold nanoparticles using Rosa hybrida petal extract at room temperature

This study reports a green method for the synthesis of gold nanoparticles using the aqueous extract of rose petals. The effects of gold salt concentration, extract concentration and extract quantity were investigated on nanoparticles synthesis. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, dynamic light scattering and transmission electron microscopy. Transmission electron microscopy experiments showed that these nanoparticles are formed with various shapes. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (-NH2), carbonyl group, -OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles. Dynamic light scattering technique was used for particle size measurement, and it was found to be about 10nm. The rate of the reaction was high and it was completed within 5 min.     

Development of diffusive solid phase microextraction method for sampling of epichlorohydrin in air

Epichlorohydrin is used frequently in many industrial processes. Exposure to this pollutant could induce harmful effects. The present work developed a novel solid phase microextraction (SPME) method for time weighted average determination of epichlorohydrin in the air by GC/MS. CAR/PDMS in 0.5?cm retracted mode was selected and the effect of environmental parameters on sampling properties of SPME was examined. Experimental sampling rate for epichlorohydrin (8.89?×?10^?3?cm³/min) was slightly less than theoretical value (9.059?×?10^?3?cm³/min). There was no significant difference among sampling rates at different temperature and velocities but relative humidity had a significant effect on the sampling rate. Limit of detection for SPME method was 0.8?ng per sample, which is good enough in comparison with the NIOSH 1010 method. Comparison of the results between the developed SPME and the NIOSH 1010 method on standard test atmosphere and field showed satisfactory agreement (y?=?1.162x?+?1.8 r ²?=?0.992 and y?=?1.009x+0.76 r ²?=?0.98 respectively).     

One‐Pot,Four‐Component Synthesis of Novel Spiro[indeno[2,1‐b]quinoxaline‐11,4′‐pyran]‐2′‐amines

A one‐pot, four‐component reaction for the efficient synthesis of novel spiro[indeno[2,1‐b]quinoxaline‐11,4′‐pyran]‐2′‐amines by using InCl₃ is described. The syntheses are achieved by reacting ninhydrin with 1,2‐diaminobenzenes to give indenoquinoxalines, which are trapped in situ by alkyl malonates and various α‐methylencarbonyl compounds through cyclization, providing multifunctionalized spiro‐substituted indeno[2,1‐b]quinoxaline‐11,4′‐pyran‐2′‐amines.     

Synthesis,experimental and DFT studies on crystal structure,FT-IR, 1H,and 13C NMR spectra,and evaluation of aromaticity of three derivatives of xanthens

Several derivatives of xanthenes are prepared by the condensation of aldehydes and dimedone in H₂O in the presence of a catalytic amount of trichlorotriazine. The crystalline products were characterized by FTIR, ¹H, and ¹³C NMR spectra. Density Functional Theory (DFT) calculations on the B3LYP level were used to optimize the geometry and calculate the crystal structure, FTIR, ¹H NMR and ¹³C NMR spectra of the selected synthesized compounds. We found that the values of FTIR, ¹H, and ¹³C NMR spectra obtained by the B3LYP method are in accordance with experimental data. The calculated NICS indicate that the six-membered rings in xanthenes are essentially homoaromatic.     

Immuno-Desorption Electrospray Ionization Mass Spectrometry Imaging Identifies Functional Macromolecules by Using Microdroplet-Cleavable Mass Tags

We present immunoassay-based desorption electrospray ionization mass spectrometry imaging (immuno-DESI-MSI) to visualize functional macromolecules such as drug targets and cascade signaling factors. A set of boronic acid mass tags (BMTs) were synthesized to label antibodies as MSI probes. The boronic ester bond is employed to cross-link the BMT with the galactosamine-modified antibody. The BMT can be released from its tethered antibody by ultrafast cleavage of the boronic ester bond caused by the acidic condition of sprayed DESI microdroplets containing water. The fluorescent moiety enables the BMT to work in both optical and MS imaging modes. The positively charged quaternary ammonium group enhances the ionization efficiency. The introduction of the boron element also makes mass tags readily identified because of its unique isotope pattern. Immuno-DESI-MSI provides an appealing strategy to spatially map macromolecules beyond what can be observed by conventional DESI-MSI, provided antibodies are available to the targeted molecules of interest.