Efficient synthesis of the cyclopentanone fragrances (Z)-3-(2-oxopropyl)-2-(pent-2-en-1-yl)cyclopentanone and Magnolione

This paper describes the selective syntheses of two cis-isomer-enriched cyclopentanone fragrances: (Z)-3-(2-oxopropyl)-2-(pent-2-en-1-yl)cyclopentanone (four steps, 62% overall yield, 67% cis) and Magnolione^® (five steps, 60% overall yield, 55% cis). In addition, the asymmetric synthesis of (3aR,7aS)-5-methyl-2,3,3a,4,7,7a-hexahydro-1H-inden-1-one as well as (3a′R,7a′S)-5′-methyl-2′,3′,3a′,4′,7′,7a′-hexahydrospiro[[1,3]dioxolane-2,1′-indene] has been realized by an efficient kinetic resolution, which enables the selective synthesis of the 2S,3R-isomer-enriched 3 and 4.     

Optimization of matrix solid-phase dispersion extraction method for the analysis of isoflavones in Trifolium pratense

A method based on matrix solid-phase dispersion (MSPD) has been developed for the determination of 12 isoflavones in Trifolium pratense L. Dried leaf samples were blended with C₁₈, placed in small columns and isoflavones extracted with dichloromethane–methanol. Analyses were performed by high performance liquid chromatography with diode array detection (HPLC-DAD) with 2-methoxyflavone as internal standard. Several dispersants, eluents and clean-up steps were tested during the optimization of the process in order to obtain the best selectivity and yields. Mean recoveries ranged from 70% to 119%, with relative standard deviations <18%. The limits of detection were between 0.006 mg/l for biochanin A and 0.108 mg/l for daidzin. The performance of the optimized method in real samples was compared with a conventional method based in solid–liquid extraction (SLE).     

Synthesis and applications of surface-grafted Th(IV)-imprinted polymers for selective solid-phase extraction of thorium(IV)

A new functional monomer N-(o-carboxyphenyl)maleamic acid (CPMA) was synthesized and chosen for the preparation of surface-grafted ion-imprinted polymers (IIPs) specific for thorium(IV). Polymerizable double bond was introduced to silica gel surface by amidation reaction between -NH₂ and maleic anhydride. In the ion-imprinting process, thorium(IV) was complexed with the carboxyl groups, then was imprinted in the polymers grafted to the silica gel surface. The imprinted Th(IV) was removed with 3 mol L⁻¹ HCl. The obtained imprinted particles exhibited excellent selectivity and rapid kinetics process for Th(IV). The relatively selective factor (α_r) values of Th(IV)/La(III), Th(IV)/Ce(III), Th(IV)/Nd(III), Th(IV)/U(VI), and Th(IV)/Zr(IV) were 85.7, 88.9, 26.6, 64.4, and 433.8, respectively, which were greater than 1. The precision (R.S.D.), the detection limit (3σ), and the quantification limit (10σ) of the method were 1.9%, 0.51 ng mL⁻¹ and 1.19 ng mL⁻¹, respectively. The prepared IIPs as solid-phase extractants were successfully applied for the preconcentration of trace thorium in natural and certified samples prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) with satisfactory results.     

Synthesis, characterisation and complex forming ability towards ferric ions of oligo(ether-amide)s of Jeffamines ED and chelidamic acid

New chelating oligo(ether-amide)s (CA-PE)s containing chelidamic acid residues in the main chain were prepared by reacting chelidamic acid with Jeffamines ED^® in the presence of N,N^′-dicyclohexylcarbodiimide and 4-dimethylaminopyridine. A mixture of products having one or two polyether sequences with chelidamate end-groups was obtained. It was found spectrophotometrically that CA-PE polymers formed a complex with Fe³⁺ at pH 3-6 having a maximum absorbance in the 472-495 nm range. Fe³⁺ ion complexes of CA-PE were water soluble, except Fe³⁺-CA-PE₆₀₀. The stoichiometric ratio between chelidamic acid residues of oligo(ether-amide)s CA-PE and Fe³⁺ ions was found to be 2 at pH 5 by the method of shift of equilibrium. A hydroxypyridine structure of the chelidamic acid residues in the complex was suggested.     

New superporous hydrogels composites based on aqueous Carbopol solution (SPHCcs): synthesis, characterization and in vitro bioadhesive force studies

In this investigation new superporous hydrogels composites based on aqueous Carbopol^® solution (SPHCcs) were prepared. SEM images indicated that the inner surface of SPHCcs contained a lot of pores connected each other and the outer surface of them was non-porous. The swelling ratio decreased with increasing the content of aqueous Carbopol^® solution, and the final swelling ratio was similar to that of the SPH although the initial swelling ratio was lower. The density measurement revealed that the porosity increased when aqueous Carbopol^® solution was incorporated. It was observed from in vitro bioadhesive force study that SPHCcs adhered to the intestinal mucosal more quickly and exhibited higher mucoadhesion as compared with SPH. It is evident that the hydrogels synthesized in this study could be a potential candidate for transmucosal drug delivery system.     

Degradation behavior of electrospun microfibers of blends of poly(lactide-co-glycolide) and Pluronic F-108

Electrospun poly(dl-lactide-co-glycolide) (PLGA) microfibers have been explored as extra cellular matrix mimicking scaffolding systems for tissue engineering application. However, the hydrophobic nature of PLGA can be limiting in terms of protein adsorption. Hence, blending of PLGA with a hydrophilic polymer (Pluronic^®) prior to electrospinning has been explored as a potential strategy to impart hydrophilicity to PLGA microfibers. In this study, PLGA (85/15) was blended with small quantities (0.5-2% w/v) of Pluronic^® F-108 (PF-108) and electrospun into microfibers. Blending of PF-108 demonstrated a significant decrease in the surface hydrophilicity of microfibers as was evidenced by an increase in wetting tension. Surface analysis using XPS indicated the presence of PF-108 in the bulk of the fibers in addition to the surface of the fibers. The results of the water uptake studies indicated that the water uptake capacity and consequential fiber swelling was significantly increased in the presences of PF-108. The in vitro degradation studies demonstrated that the trend in molecular weight loss was not significantly influenced by the presence of small quantities of PF-108. Therefore, blending of PLGA with PF-108 could be an effective technique for surface modification of electrospun PLGA microfibers without compromising on the other advantages of PLGA.     

Evaluation of two aquatic passive sampling configurations for their suitability in the analysis of estrogens in water

The presence of estrogens in the aquatic environment has been the target of several studies in the last decade. Newly developed passive sampling techniques for polar organic chemicals show great promise for the assessment of long-time exposure of aquatic organisms to emerging contaminants. In the present work, two configurations of the Chemcatcher^® passive sampler have been tested for their applicability to the analysis of seven estrogens in water. Accumulation experiments in the laboratory, to calculate the uptake rates, and a field trial show that the polar configuration of this device may be used for the efficient sampling and determination of estrogens in water. Time weighted average concentrations were determined in the field trial and compared with spot sampling concentrations. The detection of estriol using passive sampling, although not found with spot sampling, clearly demonstrates the value of this technique in assessing relevant concentrations of estrogens in the aquatic media.     

Evaluation and application of Diffusive Gradients in Thin Films (DGT) technique using Chelex-100, Metsorb™ and Diphonix binding phases in uranium mining environments

A new resin- Diphonix^® in Diffusive Gradients in Thin Films (DGT) technique for the determination of uranium was investigated and compared with previously used binding phases for uranium, Chelex^®-100 and Metsorb™. The DGT gel preparation and the elution procedure were optimized for the new resin. The U uptake on Diphonix^® resin gel was 97.4 ± 1.5% (batch method; [U] = 20 μg L⁻¹; 0.01 M NaNO₃; pH = 7.0 ± 0.2). The optimal eluent was found to be 1 M 1-hydroxyethane-1, 1-diphosphonic acid (HEDPA) with an elution efficiency of 80 ± 4.2%. Laboratory DGT study on U accumulation using a DGT samplers with Diphonix^® resin showed a very good performance across a wide range of pH (3–9) and ionic strength (0.001–0.7 M NaNO₃). Diffusion coefficients of uranium at different pH were determined using both, a diffusion cell and the DGT time-series, demonstrating the necessity of the implementation of the effective diffusion coefficients into U-DGT calculations. Diphonix^® resin gel exhibits greater U capacity than Chelex^®-100 and Metsorb™ binding phase gels (a Diphonix^® gel disc is not saturated, even with loading of 10.5 μmol U). Possible interferences with Ca²⁺ (up to 1.33 × 10⁻² M), PO₄³⁻${{\text{PO}}_4}^{3\mathrm{-}}$ (up to 1.72 × 10⁻⁴ M), SO₄²⁻${{\text{SO}}_4}^{2\mathrm{-}}$ (up to 4.44 × 10⁻³ M) and −HCO₃${{\text{HCO}}_3}^{\mathrm{-}}$ (up to 8.20 × 10⁻³ M) on U-DGT uptake ([U] = 20 μg L⁻¹) were investigated. No effect or minor effect of Ca²⁺, PO₄³⁻${{\text{PO}}_4}^{3\mathrm{-}}$, SO₄²⁻${{\text{SO}}_4}^{2\mathrm{-}}$, and −HCO₃${{\text{HCO}}_3}^{\mathrm{-}}$ on the quantitative measurement of U by Diphonix^®-DGT was observed. The results of this study demonstrated the DGT technique with Diphonix^® resin is a reliable and robust method for the measurement of labile uranium species under laboratory conditions.     

Development of microwave-assisted extraction followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry for quantification of camphor and borneol in Flos Chrysanthemi Indici

In the work, microwave-assisted extraction (MAE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for quantitative analysis of the bioactive components of camphor and borneol in a traditional Chinese medicines (TCM) of Flos Chrysanthemi Indici. After systematical investigation, the optimal experimental parameters microwave power (400 W), irradiation time (4 min), fiber coating (PDMS/DVB fiber), extraction temperature (40 °C), extraction time (20 min), stirring rate (1100 rpm), and salt effect (no salt added) were investigated. The optimized method provided satisfactory precision (RSD values less than 12%), good recovery (from 86% to 94%), and good linearity (R² > 0.999). The proposed method was applied to quantitative analysis of camphor and borneol in Flos Chrysanthemi Indici samples from 11 different growing areas. To demonstrate the method feasibility, steam distillation was also used to analyze camphor and borneol in Flos Chrysanthemi Indici samples from these different growing areas. The very close results were obtained by the two methods. It has been shown that the proposed ME-HS-SPME-GC-MS is a simple, rapid, solvent-free and reliable method for quantitative analysis of camphor and borneol in TCM, and a potential tool for quality assessment of Flos Chrysanthemi Indici.     

A simple one-pot synthesis of β-alkoxy alcohols from alkenes

β-Methoxy alcohols are easily obtained from the one-pot reaction of alkenes with oxone^® in methanol, in the absence of any additive or catalyst. The use of other alcohols as solvents has shown that the efficiency of the process decreases with the steric hindrance of the alcohol.     

Identification and quantification of 13 components in Angelica sinensis (Danggui) by gas chromatography-mass spectrometry coupled with pressurized liquid extraction

Angelica sinensis (Danggui in Chinese), a well-known traditional Chinese medicine, is also used as a health food product for women's care in Europe and America. Therefore, the demand for Danggui is enormous throughout the world. Due to the shortage of Angelica sinensis, Angelica acutiloba and Angelica gigas are commonly used as the substitutes of Danggui in the market of southeast Asia. However, the three common Angelica roots showed variation in their genetic and chemical composition. Up to date, it is thought that ferulic acid, ligustilide and other phthalides such as butylidenephthalide are the biologically active components of Danggui. In this paper, the contents of 13 compounds including ferulic acid, Z-ligustilide, E-ligustilide, Z-butylidenephthalide, E-butylidenephthalide, 3-butylphthalide, 3-butylidene-4-hydroxyphthalide, senkyunolide A, 6,7-epoxyligustilide, senkyunolide F, senkyunolide H, senkyunolide I, and 6,7-dihydroxyligustilide were determined or estimated by using gas chromatography-mass spectrometry (GC-MS) coupled with pressurized liquid extraction (PLE). The results showed that GC-MS coupled with PLE offered a simple, rapid and high sensitive method to analysis of components in Angelica root. And the contents of investigated compounds in Angelica sinensis, Angelica acutiloba and Angelica gigas, which are used as Danggui in China, Japan and Korea, respectively, were highly variant. It is thought that interaction of multiple chemical compounds contributes to the therapeutic effects of Chinese medicines. However, the overall clinical efficacy of these different Danggui has not been determined. Therefore, comparison of chemical components and pharmacological activities of different Angelica root is helpful to elucidate the mechanism of therapeutic effects of Danggui.     

Novel thionin-functionalised core shell magnetic nanoparticles for dispersive solid-phase extraction of Hg(II) in food and water samples

To develop an accurate and precise method for separation and pre-concentration of Hg(II), a novel thionin functionalised core shell structure magnetic material has been prepared and characterised. The extraction ability of the material was evaluated by magnetic solid-phase extraction coupled with inductively coupled plasma mass spectrometry determination of Hg(II) in food and water samples. Combining the advantages of magnetic separation with selective extraction of thionin towards Hg(II), the material exhibits enhanced enrich selectivity and efficiency for Hg(II). The experimental parameters influencing Hg(II) extraction efficiency, including pH of the aqueous solution, the dosage of the adsorbent, extraction time and sample volume, were systematically investigated. Under the optimised conditions, concentration of Hg(II) at 1.0 μg L^?1 can be successfully enriched by the material without the interference of the common co-existing ions. The enrichment factor and adsorption capacity were 250 and 75.2 mg g^?1, and precise of the method was confirmed by analysing the spiked food, water samples and standard water reference samples with the recoveries of 92.5–101.8%.     

Selective solid-phase extraction of trace Fe(III) from biological and natural water samples using nanometer SiO2 modified with acetylsalicylic acid

A new method using acetylsalicylic acid (aspirin) modified SiO₂ nanoparticles (nanometer SiO₂-aspirin) as a solid-phase extractant (SPE) has been developed for the preconcentration of trace amounts of Fe(III) prior to their determination by inductively coupled plasma optical emission spectrometry. The preconcentration conditions of analytes were investigated, including the pH value, the shaking time, the mass of sorbent, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the sorption capacity of nanometer SiO₂-aspirin was found to be 1.28 mmol g⁻¹. The preconcentration factor is 50. The detection limit (3σ) for Fe(III) was 0.49 ng mL⁻¹. The method was validated by analyzing two certified reference materials (GBW 08301, river sediment and GBW 08303, polluted farming soil), and the results obtained are in good agreement with standard values. The method was also applied to the determination of trace Fe(III) in biological and water samples with satisfactory results. Correspondence: Xiangbing Zhu, Department of Chemistry, Lanzhou University, Lanzhou 730000, P.R. China     

Chemically modified silica gel with p-dimethylaminobenzaldehyde for selective solid-phase extraction and preconcentration of Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) by ICP-OES

Silica gel-bound amines phase modified with p-dimethylaminobenzaldehyde (p-DMABD) was prepared based on chemical immobilization technique. The product (SG-p-DMABD) was used as an adsorbent for the solid-phase extraction (SPE) Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The uptake behaviors of SG-p-DMABD for extracting these metal ions were studied using batch and column procedures. For the batch method, the optimum pH range for Cr(III) and Ni(II) extraction was ≥ 3, for Cu(II), Pb(II) and Zn(II) extraction it was ≥ 4. For simultaneous enrichment and determination of all the metals on the newly designed adsorbent, the pH value if 4.0 was selected. All the metal ions can be desorbed with 2.0 mL of 0.5 mol L^− 1 of HCl. The results indicate that SG-p-DMABD has rapid adsorption kinetics using the batch method. The adsorption capacity for these metal ions is in the range of 0.40-1.15 mmol g^− 1, with a high enrichment factor of 125. The presence of commonly coexisting ions does not affect the sorption capacities. The detection limits of the method were found to be 1.10, 0.69, 0.99, 1.10 and 6.50 μg L^− 1 for Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The relative standard deviation (RSD) of the method under optimum conditions was 5.0% (n = 8) for all metal ions. The method was applied to the preconcentration of Cr(III), Cu(II), Ni(II), Pb(II) and Zn(II) from the certified reference material (GBW 08301, river sediment) and water samples with satisfactory results.     

Synthetic studies on basidifferquinones: the first synthesis of (±)-basidifferquinone C

Basidifferquinones, isolated from Streptomyces sp., are potent inducers for fruiting-body formation of a basidiomycete Polyporus arcularius. Construction of the basic framework of basidifferquinones and the first synthesis of (±)-basidifferquinone C were accomplished by starting from 3,5-dihydroxy-2-naphthoic acid.     

Preconcentration and separation of copper (II) with solvent extraction using N,N′-bis(2-hydroxy-5-bromo-benzyl)1,2 diaminopropane

Preconcentration and separation with solvent extraction of Cu(II) from aqueous solution using N,N′-bis(2-hydroxy-5-bromo-benzyl)1,2 diaminopropane (H₂L) as the new extractant has been studied. Separation of Cu(II) from other metal ions such as Cd(II), Ni(II), Zn(II), Pb(II), Cr(III), Co(II) and Mn(II) at aqueous solutions of various pH values and complexing agent H₂L, has been described. The possible extraction mechanism and the compositions of the extracted species have been determined. The separation factors for these metals using this reagent are reported while efficient methods for the separation of Cu(II) from other metal ions are proposed. From the loaded organic phase, Cu(II) stripping was carried out in one stage with different mineral acid solutions. The stripping efficiency was found to be quantitative in case of HNO₃ and HCl. From quantitative evaluation of the extraction equilibrium data, it has been deduced that the complex extracted is the simple 1:1 chelate, CuL. The extraction constant has a value of logK_ex=−4.05±0.04.     

Rapid and efficient microwave-assisted synthesis of 5-amino-3-aralkoxy(methoxy)amino-1,2,4-oxadiazoles

The microwave-assisted synthesis of 5-amino-3-aralkoxy(methoxy)amino-1,2,4-oxadiazoles starting from N¹-aralkoxy-(methoxy)-N³-cyano-O-phenylisoureas and hydroxylamine is described. N¹-Aralkoxy(methoxy)-N³-cyano-O-phenylisoureas are readily accessible by treatment of diphenyl N-cyanimidocarbonate with O-substituted hydroxylamines.     

Retention profile and subsequent chemical speciation of chromium (III) and (VI)) in industrial wastewater samples employing some onium cations loaded polyurethane foams

The retention of chromium (VI) from aqueous media onto tetraphenylarsonium chloride (TPAs⁺Cl⁻) or tetraphenylphosphonium bromide (TPP⁺Br⁻) immobilized polyurethane foams (PUFs) was fast and followed first order reaction. The kinetic data of the retention step were subjected to Weber-Morris, Lagergren, Bhattacharya and Venkobachar and Bt kinetic models. The results revealed that, film and intraparticle transport might be the two steps controlling the rate of chromium (VI) sorption from the aqueous acid solutions of pH ∼ zero. The positive values of the Δ H of chromium (VI) retention by the reagents loaded PUFs were interpreted as an endothermic process. Under the optimum pH (pH ∼ zero ) of the aqueous solution, the proposed TPAs⁺Cl⁻ or TPP⁺Br⁻ immobilized PUFs was successfully used in a series of medical syringe (30, 50 mL capacity) as pulse columns for complete collection of chromium (VI) species present in fresh and industrial wastewater samples at ultra trace low level of chromium (VI) (≤ 0.05 μg mL^− 1). The collected chromium (VI) species onto TPAs⁺Cl⁻ or TPP⁺Br⁻-PUFs was then stripped quantitatively (98-102 ± 2.6%) from the pulse columns with NaOH (2.0 mol L^− 1) and subsequently analyzed photometrically. The chromium (VI) ions could be pre concentrated up to 100-fold from large volume of water samples. The proposed pulse foam columns were applied successfully for complete collection, recovery (97.5 ± 2.6%, n = 5) and subsequent chemical speciation of chromium (III) and (VI) in wastewater samples. The results are in good agreement with the reported and standard methods at 95% confidence.     

Determination of cadmium and lead species and phytochelatins in pea (Pisum sativum) by HPLC-ICP-MS and HPLC-ESI-MS

An analytical approach based on hyphenated techniques was used for studying the speciation of cadmium and lead in Pisum sativum. Proper preservation conditions were employed to avoid the oxidation of -SH groups and corresponding decomposition of metal-binding complexes. SEC column was washed with 5 mM beta-mercaptoethanol and then samples were analysed using ICP-MS as a detector. Results showed that cadmium is the inhibitor of lead uptake. HPLC-ESI-MSⁿ assays revealed fragmentation pathways of phytochelatins.     

Syntheses and X-ray structures of Cu(II) and Zn(II) complexes of N,N′-dibenzyl-(R,R)-1,2-diaminocyclohexane and application to nitroaldol reaction

Chiral Cu(II) and Zn(II) complexes with N,N′-dibenzyl-(R,R)-1,2-diaminocyclohexane ligands were synthesized and characterized. X-ray crystal structures of these complexes reveal that Cu complex has the distorted square-planar geometry and the Zn one has the nearly tetrahedral pattern. The coordination of metals to the chiral diamine ligand leads to a 5-membered metallaheterocycle of (S,S)-configuration of nitrogen atoms. Their asymmetric catalytic activities to nitroaldol reaction of benzaldehyde and nitromethane were examined. The difference of the geometry around metals leads to the opposite preferential configuration of alcohol products using these chiral complexes as asymmetric catalysts in the presence of triethylamine or diisopropylethylamine.