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2015 Volume 26 Issue 8
2015, 26(8): 919-921
doi: 10.1016/j.cclet.2015.06.020
Abstract:
2015, 26(8): 922-930
doi: 10.1016/j.cclet.2015.04.026
Abstract:
In order to meet the increasing demands for the development of large varieties of new molecules for discovering new drugs and materials, organic chemists are developing many novel multifunctional building blocks, which are assembled rationally to create ‘nature-like’ and yet unnatural organic molecules with well-defined structures and useful properties. Sugar amino acids (SAAs), the carbohydrate derivatives bearing both amino and carboxylic acid functional groups, are important ones of thesemultifunctional building blocks, which can be used to create novelmaterials with potential applications as glycomimetics and peptidomimetics. This review will focus on recent synthetic strategies of SAAs and their applications in creating large number of structurally diverse glycomimetics and peptidomimetics.
In order to meet the increasing demands for the development of large varieties of new molecules for discovering new drugs and materials, organic chemists are developing many novel multifunctional building blocks, which are assembled rationally to create ‘nature-like’ and yet unnatural organic molecules with well-defined structures and useful properties. Sugar amino acids (SAAs), the carbohydrate derivatives bearing both amino and carboxylic acid functional groups, are important ones of thesemultifunctional building blocks, which can be used to create novelmaterials with potential applications as glycomimetics and peptidomimetics. This review will focus on recent synthetic strategies of SAAs and their applications in creating large number of structurally diverse glycomimetics and peptidomimetics.
2015, 26(8): 931-936
doi: 10.1016/j.cclet.2015.05.052
Abstract:
A pair of indole alkaloid enantiomers with a novel bisindolylacetamide skeleton, insatindibisindolamides A and B (1a and 1b), was isolated from an aqueous extract of Isatis indigotica roots. The enantiomers were separated by chiral HPLC. Their structures and absolute configurations were elucidated by extensive spectroscopic analysis, including 2D NMR, X-ray crystallography, and electronic CD (ECD) calculation. The proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1a and 1b are also discussed.
A pair of indole alkaloid enantiomers with a novel bisindolylacetamide skeleton, insatindibisindolamides A and B (1a and 1b), was isolated from an aqueous extract of Isatis indigotica roots. The enantiomers were separated by chiral HPLC. Their structures and absolute configurations were elucidated by extensive spectroscopic analysis, including 2D NMR, X-ray crystallography, and electronic CD (ECD) calculation. The proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1a and 1b are also discussed.
2015, 26(8): 937-941
doi: 10.1016/j.cclet.2015.04.023
Abstract:
Exploring the factors to control Znsalen aggregation is of importance to design functional materials in catalysis, optical materials and biological imaging. In this work, we synthesized and characterized four cryptand type triZnsalen complexes and found that cryptand structure could efficiently minimize intermolecular Zn···O interaction. More importantly, encapsulated by PLGA nanoparticles, cryptand triZnsalen 1 displayed visible intracellular fluorescence whereas monomeric Znsalen 5 could not. These results provide a new access to design new luminescent materials with the potential application in optics and biological studies.
Exploring the factors to control Znsalen aggregation is of importance to design functional materials in catalysis, optical materials and biological imaging. In this work, we synthesized and characterized four cryptand type triZnsalen complexes and found that cryptand structure could efficiently minimize intermolecular Zn···O interaction. More importantly, encapsulated by PLGA nanoparticles, cryptand triZnsalen 1 displayed visible intracellular fluorescence whereas monomeric Znsalen 5 could not. These results provide a new access to design new luminescent materials with the potential application in optics and biological studies.
2015, 26(8): 942-945
doi: 10.1016/j.cclet.2015.04.034
Abstract:
Poly(ionic liquid) functionalized composite nanotubes are achieved by ATRP grafting ionic liquid monomers for example ViEtIm+Br- from the poly(DVB-co-VBC) nanotubes surface. PW12O403- anion is introduced through anion exchange. The PW12O403- based composite nanotubes can synchronously absorb and decompose water soluble dyes for examplemethyl orange (MO). The cooperative interplay is promising in highly efficient decomposition of dyes.
Poly(ionic liquid) functionalized composite nanotubes are achieved by ATRP grafting ionic liquid monomers for example ViEtIm+Br- from the poly(DVB-co-VBC) nanotubes surface. PW12O403- anion is introduced through anion exchange. The PW12O403- based composite nanotubes can synchronously absorb and decompose water soluble dyes for examplemethyl orange (MO). The cooperative interplay is promising in highly efficient decomposition of dyes.
2015, 26(8): 946-950
doi: 10.1016/j.cclet.2015.05.016
Abstract:
Here, we report a new strategy for rapid synthesis of branched peptide by side-chain hydrazide ligation at Asn. The hydrazide was converted to thioester at Asn side chain by NaNO2 and thiol reagent, and sequential ligation with an N-terminus Cys-peptide efficiently afforded the branched peptide. A branched cyclic peptide was successfully synthesized by side-chain ligation with a two-Cys-peptide and formation of a disulfide bond. This approach provides a new way for expeditious synthesis of branched peptides and facilitates the design of neopeptides as functional bio-mimics.
Here, we report a new strategy for rapid synthesis of branched peptide by side-chain hydrazide ligation at Asn. The hydrazide was converted to thioester at Asn side chain by NaNO2 and thiol reagent, and sequential ligation with an N-terminus Cys-peptide efficiently afforded the branched peptide. A branched cyclic peptide was successfully synthesized by side-chain ligation with a two-Cys-peptide and formation of a disulfide bond. This approach provides a new way for expeditious synthesis of branched peptides and facilitates the design of neopeptides as functional bio-mimics.
2015, 26(8): 951-954
doi: 10.1016/j.cclet.2015.03.027
Abstract:
Two series of phenothiazine derivatives were designed and synthesized. All compounds were tested for anti-tuberculosis activities against Mycobacterium tuberculosis H37RV. In comparison with mother compound of chlorpromazine, compound 6e shows promising anti-tuberculosis activity and much less mammalian cell cytotoxicity, compound 6e merits to be further explored as new anti-tuberculosis agents.
Two series of phenothiazine derivatives were designed and synthesized. All compounds were tested for anti-tuberculosis activities against Mycobacterium tuberculosis H37RV. In comparison with mother compound of chlorpromazine, compound 6e shows promising anti-tuberculosis activity and much less mammalian cell cytotoxicity, compound 6e merits to be further explored as new anti-tuberculosis agents.
2015, 26(8): 955-962
doi: 10.1016/j.cclet.2015.03.008
Abstract:
Three new metal-free organic dyes (TX1, TX2 and TX3) based on truxene core structure, with triphenylamine as the electron donor, thiophene as the p spacers, and cyanoacetic acid or rhodanine-3-acetic acid as the electron acceptor are designed and synthesized. Their UV-vis absorption spectra, electrochemical and photovoltaic properties were investigated. The cyanoacrylic acid is verified to be a better acceptor unit (meanwhile the anchoring group) compared to the rhodanine-3-acetic acid. And also, two anchoring groups in TX2 could provide stronger adsorption ability on the TiO2 surface. In addition, the EIS results indicate a slower charge recombination processes for TX2. As a result, dye TX2 bearing two cyanoacetic acid outperforms the other two dyes, exhibiting the photo-conversion efficiency of 2.64%, with Jsc = 5.09 mA cm-2, Voc = 729 mV, FF = 71.1.
Three new metal-free organic dyes (TX1, TX2 and TX3) based on truxene core structure, with triphenylamine as the electron donor, thiophene as the p spacers, and cyanoacetic acid or rhodanine-3-acetic acid as the electron acceptor are designed and synthesized. Their UV-vis absorption spectra, electrochemical and photovoltaic properties were investigated. The cyanoacrylic acid is verified to be a better acceptor unit (meanwhile the anchoring group) compared to the rhodanine-3-acetic acid. And also, two anchoring groups in TX2 could provide stronger adsorption ability on the TiO2 surface. In addition, the EIS results indicate a slower charge recombination processes for TX2. As a result, dye TX2 bearing two cyanoacetic acid outperforms the other two dyes, exhibiting the photo-conversion efficiency of 2.64%, with Jsc = 5.09 mA cm-2, Voc = 729 mV, FF = 71.1.
2015, 26(8): 963-968
doi: 10.1016/j.cclet.2015.03.037
Abstract:
An efficient methodology for the synthesis of 2,3-disubstituted 3H-quinazolin-4-ones is described via one-pot three component reaction from anthranilic acid using T3P as catalyst. Mild reaction conditions, short reaction time, broad functional group tolerance, easy isolation of products and good yields are main advantages of this protocol.
An efficient methodology for the synthesis of 2,3-disubstituted 3H-quinazolin-4-ones is described via one-pot three component reaction from anthranilic acid using T3P as catalyst. Mild reaction conditions, short reaction time, broad functional group tolerance, easy isolation of products and good yields are main advantages of this protocol.
2015, 26(8): 969-972
doi: 10.1016/j.cclet.2015.04.020
Abstract:
A direct C-H amination reaction of N-Ts-2-Styrylaniline derivatives to realize the synthesis of indole derivatives was developed in the presence of copper salt. A variety of N-Ts-2-Styrylaniline derivatives were transformed into the corresponding indole products in good to excellent yield under mild conditions with the oxidation of potassium persulfate.
A direct C-H amination reaction of N-Ts-2-Styrylaniline derivatives to realize the synthesis of indole derivatives was developed in the presence of copper salt. A variety of N-Ts-2-Styrylaniline derivatives were transformed into the corresponding indole products in good to excellent yield under mild conditions with the oxidation of potassium persulfate.
2015, 26(8): 973-976
doi: 10.1016/j.cclet.2015.04.016
Abstract:
An efficient and convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives is described, using the electrogenerated anion of ethanol as the base in the presence of sodium bromide as an supporting electrolyte in a one-pot, three component condensation of malononitrile, aromatic aldehydes and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one. The reaction is carried out in an undivided cell containing an iron electrode as the cathode and a graphite electrode as the anode, at a constant current at room temperature.
An efficient and convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives is described, using the electrogenerated anion of ethanol as the base in the presence of sodium bromide as an supporting electrolyte in a one-pot, three component condensation of malononitrile, aromatic aldehydes and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one. The reaction is carried out in an undivided cell containing an iron electrode as the cathode and a graphite electrode as the anode, at a constant current at room temperature.
2015, 26(8): 977-979
doi: 10.1016/j.cclet.2015.05.008
Abstract:
A novel and facile synthesis of 4-arylquinolin-2(1H)-ones without metal catalysis has been developed. This reaction involved cyclization/elimination steps and was performed under metal-free conditions using inexpensive reagents such as NaI, selectfluor and KOH.
A novel and facile synthesis of 4-arylquinolin-2(1H)-ones without metal catalysis has been developed. This reaction involved cyclization/elimination steps and was performed under metal-free conditions using inexpensive reagents such as NaI, selectfluor and KOH.
2015, 26(8): 980-982
doi: 10.1016/j.cclet.2015.05.011
Abstract:
The lack of suitable lignin model compound limits the understanding of the characteristics of lignin, and hence hinders the efficient utilization of this kind of bioresource. A tetramer phenolic lignin model compound composed of 5-5, α-O-4 and β-5 linkages was prepared by a two-step of free radical reaction with hydrogen peroxide/horseradish peroxidase and S2O82- /Fe2+ as the initiator. Compared with enzymatic process, this synthetic process gives a higher yield of 33.8% within a shorter time. HRMS and 13C NMR spectroscopy show that synthesized model compound contains phenylpropane structure linked by 5-5, α-O-4 and β-5 bonds, which can mimic some chemical characteristics of lignin.
The lack of suitable lignin model compound limits the understanding of the characteristics of lignin, and hence hinders the efficient utilization of this kind of bioresource. A tetramer phenolic lignin model compound composed of 5-5, α-O-4 and β-5 linkages was prepared by a two-step of free radical reaction with hydrogen peroxide/horseradish peroxidase and S2O82- /Fe2+ as the initiator. Compared with enzymatic process, this synthetic process gives a higher yield of 33.8% within a shorter time. HRMS and 13C NMR spectroscopy show that synthesized model compound contains phenylpropane structure linked by 5-5, α-O-4 and β-5 bonds, which can mimic some chemical characteristics of lignin.
2015, 26(8): 983-987
doi: 10.1016/j.cclet.2015.04.012
Abstract:
In the present letter, an efficient, clean and one-pot synthesis of 2-substituted benzimidazole and 1,2-disubstituted benzimidazole derivatives has been explored by reacting o-phenylenediamine with aromatic aldehydes using bismuth nitrate as a catalyst in ethanol at ambient temperature. This methodology avails with faster reactions, excellent yield, mild reaction conditions, use of inexpensive and non-toxic catalyst compared to literature reported hitherto.
In the present letter, an efficient, clean and one-pot synthesis of 2-substituted benzimidazole and 1,2-disubstituted benzimidazole derivatives has been explored by reacting o-phenylenediamine with aromatic aldehydes using bismuth nitrate as a catalyst in ethanol at ambient temperature. This methodology avails with faster reactions, excellent yield, mild reaction conditions, use of inexpensive and non-toxic catalyst compared to literature reported hitherto.
2015, 26(8): 988-992
doi: 10.1016/j.cclet.2015.05.001
Abstract:
Ionic liquids (ILs) immobilized on silica as novel high performance liquid chromatography (HPLC) stationary phases have attracted considerable attention. However, it has not been applied to protein separation. In this paper, N-methylimidazolium IL-modified silica-based stationary phase (SilprMim) was prepared and investigated as a novel multi-interaction stationary phase charged positively for protein separation. The results indicate that all of the basic proteins tested cannot be absorbed on this novel stationary phase, whereas all of the acidic proteins tested can be retained, and the baseline separation of eight kinds of acidic protein standards can be achieved when performed in reversed phase/ ion-exchange chromatography (RPLC/IEC) mode. Compared with commonly used commercial octadecylated silica (ODS) column, the novel stationary phase can show selectivity and good resolution to acidic proteins, which has a promising application in the separation and analyses of acidic proteins from the complex samples in proteomics. In addition, the chromatographic behavior of proteins, the effect of the ligand structure and the retention mechanism on this stationary phase were also investigated.
Ionic liquids (ILs) immobilized on silica as novel high performance liquid chromatography (HPLC) stationary phases have attracted considerable attention. However, it has not been applied to protein separation. In this paper, N-methylimidazolium IL-modified silica-based stationary phase (SilprMim) was prepared and investigated as a novel multi-interaction stationary phase charged positively for protein separation. The results indicate that all of the basic proteins tested cannot be absorbed on this novel stationary phase, whereas all of the acidic proteins tested can be retained, and the baseline separation of eight kinds of acidic protein standards can be achieved when performed in reversed phase/ ion-exchange chromatography (RPLC/IEC) mode. Compared with commonly used commercial octadecylated silica (ODS) column, the novel stationary phase can show selectivity and good resolution to acidic proteins, which has a promising application in the separation and analyses of acidic proteins from the complex samples in proteomics. In addition, the chromatographic behavior of proteins, the effect of the ligand structure and the retention mechanism on this stationary phase were also investigated.
2015, 26(8): 993-999
doi: 10.1016/j.cclet.2015.05.003
Abstract:
A total of 11 novel combretastatin A-4 (CA-4) analogs were designed, synthesized, and evaluated for the anti-proliferative effects in tumor cells. The compounds represent four structural classes: (i) hydrogenated derivatives, (ii) ethoxyl derivatives, (iii) amino derivatives and (iv) pro-drugs. Biological evaluations demonstrate that multiple structural features control the biological potency. Three of the compounds, sit-1, sit-2 and sit-3, have potent anti-proliferative activity against multiple cancer cell lines. Their pro-drugs were synthesized to increase water solubility. Structure-activity relationship study and Surflex-Docking were studied in this paper. These results will be useful for the design of new CA-4 analogs that are structurally related to the SAR study.
A total of 11 novel combretastatin A-4 (CA-4) analogs were designed, synthesized, and evaluated for the anti-proliferative effects in tumor cells. The compounds represent four structural classes: (i) hydrogenated derivatives, (ii) ethoxyl derivatives, (iii) amino derivatives and (iv) pro-drugs. Biological evaluations demonstrate that multiple structural features control the biological potency. Three of the compounds, sit-1, sit-2 and sit-3, have potent anti-proliferative activity against multiple cancer cell lines. Their pro-drugs were synthesized to increase water solubility. Structure-activity relationship study and Surflex-Docking were studied in this paper. These results will be useful for the design of new CA-4 analogs that are structurally related to the SAR study.
2015, 26(8): 1000-1003
doi: 10.1016/j.cclet.2015.05.004
Abstract:
Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one new labdane diterpenoid, leojaponin D (1) and two new ionone derivatives, leojaponones A and B (2 and 3), together with seven known diterpenoids (4-10). Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and by comparison with data reported in the literature. Selected isolates were evaluated their effects on Jurkat IL2 secretion.
Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one new labdane diterpenoid, leojaponin D (1) and two new ionone derivatives, leojaponones A and B (2 and 3), together with seven known diterpenoids (4-10). Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and by comparison with data reported in the literature. Selected isolates were evaluated their effects on Jurkat IL2 secretion.
2015, 26(8): 1004-1007
doi: 10.1016/j.cclet.2015.03.013
Abstract:
A series of Nd3+-doped Li3NdxV2-x(PO4)3 (x = 0.00, 0.02, 0.05, 0.08 or 0.1) composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3+ ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0-4.3 V, Li3Nd0.08V1.92(PO4)3 exhibits an initial discharge capacity of 115.8 mAh/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51st cycle. In addition, Li3Nd0.05V1.95(PO4)3 holds at 100.4 mAh/g after 80 cycles at 0.2 C with a capacity retention of 92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92(PO4)3 decreased compared with the un-doped one.
A series of Nd3+-doped Li3NdxV2-x(PO4)3 (x = 0.00, 0.02, 0.05, 0.08 or 0.1) composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3+ ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0-4.3 V, Li3Nd0.08V1.92(PO4)3 exhibits an initial discharge capacity of 115.8 mAh/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51st cycle. In addition, Li3Nd0.05V1.95(PO4)3 holds at 100.4 mAh/g after 80 cycles at 0.2 C with a capacity retention of 92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92(PO4)3 decreased compared with the un-doped one.
2015, 26(8): 1008-1010
doi: 10.1016/j.cclet.2015.04.008
Abstract:
A series of novel self-dispreading phenoxy carboxylic acid derivatives were designed and synthesized by I2 catalyzed one-step reaction. Their structures were confirmed by IR, NMR, and HRMS. The derivatives can self-spread and float on the water surface. Preliminary bioassays showed that some compounds, 3i-3p, had excellent herbicidal activities against water hyacinth. This strategy provided a novel approach for the water hyacinth control.
A series of novel self-dispreading phenoxy carboxylic acid derivatives were designed and synthesized by I2 catalyzed one-step reaction. Their structures were confirmed by IR, NMR, and HRMS. The derivatives can self-spread and float on the water surface. Preliminary bioassays showed that some compounds, 3i-3p, had excellent herbicidal activities against water hyacinth. This strategy provided a novel approach for the water hyacinth control.
2015, 26(8): 1011-1015
doi: 10.1016/j.cclet.2015.05.019
Abstract:
To produce β-glucosidase by consecutive batch fermentation, amarine Aspergillus niger was immobilized on a natural carrier, towel gourd vegetable sponges. The immobilized mycelia were 0.15 g/g carrier with the immobilized biomass percentage of over 95%. The immobilized mycelia possessed the long durability (22.5 days). The maximum production occurred 1.5 day earlier by the immobilized mycelia than by the free mycelia. β-Glucosidase production of five consecutive batches was over 110 U/mL. At high salinity, the activity and stability of β-glucosidase from the marine A. niger increased remarkable. Immobilizing the marine A. niger on the novel natural carrier achieved the efficient production of β-glucosidase.
To produce β-glucosidase by consecutive batch fermentation, amarine Aspergillus niger was immobilized on a natural carrier, towel gourd vegetable sponges. The immobilized mycelia were 0.15 g/g carrier with the immobilized biomass percentage of over 95%. The immobilized mycelia possessed the long durability (22.5 days). The maximum production occurred 1.5 day earlier by the immobilized mycelia than by the free mycelia. β-Glucosidase production of five consecutive batches was over 110 U/mL. At high salinity, the activity and stability of β-glucosidase from the marine A. niger increased remarkable. Immobilizing the marine A. niger on the novel natural carrier achieved the efficient production of β-glucosidase.
2015, 26(8): 1016-1018
doi: 10.1016/j.cclet.2015.05.012
Abstract:
The potentially bioactive 2-aryl-thiazolo[4,5-b]pyridines were synthesized via palladium-catalyzed desulfitative cross-coupling reaction between multisubstituted thiazolo[4,5-b]pyridine thioethers and boronic acids. Yields of 48%-94% were obtained with copper(I) thiophene-2-carboxylate in the system.
The potentially bioactive 2-aryl-thiazolo[4,5-b]pyridines were synthesized via palladium-catalyzed desulfitative cross-coupling reaction between multisubstituted thiazolo[4,5-b]pyridine thioethers and boronic acids. Yields of 48%-94% were obtained with copper(I) thiophene-2-carboxylate in the system.
2015, 26(8): 1019-1021
doi: 10.1016/j.cclet.2015.04.027
Abstract:
The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu (II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu (II). The ΔA could be increased to 0.12 by changing the ratio of (+)-and (-)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus ΔA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.
The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu (II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu (II). The ΔA could be increased to 0.12 by changing the ratio of (+)-and (-)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus ΔA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.
2015, 26(8): 1022-1025
doi: 10.1016/j.cclet.2015.04.029
Abstract:
In this work, a separated-electrode piezoelectric sensor (SEPS), constructed by a naked quartz crystal mounted between two electrodes, is reported for applications in a corrosive gaseous phase. The response of SEPS was measured by an impedance analysis method. It was shown that SEPS has an excellent frequency stability because its quality factor is in the order of 105. The SEPS can be operated even with the electrode gap in air larger than 1 cm. Compared with a conventional quartz crystal microbalance, the resonant frequency of the SEPS is independent of the mass change in the electrode. The SEPS was applied to monitor the adsorption of iodine on quartz surface and zeolitic-imidazolate framework-8 (ZIF-8) film as well as in the transfer of iodine between two ZIF-8 films. The SEPS offers the advantages of easy preparation, corrosion-resistant and convenience in combination with mass and optical measurements.
In this work, a separated-electrode piezoelectric sensor (SEPS), constructed by a naked quartz crystal mounted between two electrodes, is reported for applications in a corrosive gaseous phase. The response of SEPS was measured by an impedance analysis method. It was shown that SEPS has an excellent frequency stability because its quality factor is in the order of 105. The SEPS can be operated even with the electrode gap in air larger than 1 cm. Compared with a conventional quartz crystal microbalance, the resonant frequency of the SEPS is independent of the mass change in the electrode. The SEPS was applied to monitor the adsorption of iodine on quartz surface and zeolitic-imidazolate framework-8 (ZIF-8) film as well as in the transfer of iodine between two ZIF-8 films. The SEPS offers the advantages of easy preparation, corrosion-resistant and convenience in combination with mass and optical measurements.
2015, 26(8): 1026-1030
doi: 10.1016/j.cclet.2015.05.002
Abstract:
A new stationary phase for iodide ion analysis has been developed. The cationic polymerepichlorohydrin-dimethylamine (PEPI-DMA) was served as modifier in synthesizing polyelectrolyte sorbents and the macroporous polystyrene-divinylbenzene (PS-DVB) resin was used as support. The positively charged polymer (PEPI-DMA) was electrostatically bonded to a negatively charged particle (PS-DVB sulfonated). The new stationary phase was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), elemental analysis, chemical adsorption and desorption measurements. The chromatographic evaluation of the new stationary phase was performed using various anions with a conductivity detector. The new stationary phase was also applied to the determination of iodide directly with a DC amperometric detector using a platinum working electrode and an Ag/AgCl reference electrode. The chromatographic conditions were optimized and the eluent solution contained 5 mmol/L HNO3 and 15 mmol/L NaNO3 at a flow rate of 1.0 mL/min and column temperature of 30 ℃. The applied voltage of the DC amperometric detector was 0.9 V. Under the optimum conditions, the linear range of the method was 0.2-50 mg/L for iodide ion with a correlation coefficient of 0.9990. The detection limit was 0.05 mg/L (calculated at S/N = 3) and the relative standard deviations (RSD, n = 6) were all less than 1% for retention time, peak area and peak height. This method was also utilized for the determination of iodide ions in samples of povidone iodine solution and kelp samples with satisfactory results.
A new stationary phase for iodide ion analysis has been developed. The cationic polymerepichlorohydrin-dimethylamine (PEPI-DMA) was served as modifier in synthesizing polyelectrolyte sorbents and the macroporous polystyrene-divinylbenzene (PS-DVB) resin was used as support. The positively charged polymer (PEPI-DMA) was electrostatically bonded to a negatively charged particle (PS-DVB sulfonated). The new stationary phase was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), elemental analysis, chemical adsorption and desorption measurements. The chromatographic evaluation of the new stationary phase was performed using various anions with a conductivity detector. The new stationary phase was also applied to the determination of iodide directly with a DC amperometric detector using a platinum working electrode and an Ag/AgCl reference electrode. The chromatographic conditions were optimized and the eluent solution contained 5 mmol/L HNO3 and 15 mmol/L NaNO3 at a flow rate of 1.0 mL/min and column temperature of 30 ℃. The applied voltage of the DC amperometric detector was 0.9 V. Under the optimum conditions, the linear range of the method was 0.2-50 mg/L for iodide ion with a correlation coefficient of 0.9990. The detection limit was 0.05 mg/L (calculated at S/N = 3) and the relative standard deviations (RSD, n = 6) were all less than 1% for retention time, peak area and peak height. This method was also utilized for the determination of iodide ions in samples of povidone iodine solution and kelp samples with satisfactory results.
2015, 26(8): 1031-1035
doi: 10.1016/j.cclet.2015.05.036
Abstract:
This report described a free-enzyme, convenient and inexpensive genotyping biosensor capable of detecting single nucleotide polymorphism at normal temperature based on the combination of toeholdmediated strand displacement reaction (toehold-SDR) and microbead-capture technique. The biosensor consists of a pre-hybridized strand formed by a reporter probe and a capture probe. In the presence of a mutant sequence, there is no toehold-mediated strand displacement and the reporter probe cannot be released from the pre-hybridized strand. Microbeads capture the fluorescent pre-hybridized strand through biotin-streptavidin interaction, so microbeads give out significant fluorescence signal, while there is no fluorescence in the solution. However, in the presence of a matched target, the strand displacement is effectively initiated and the reporter probe is released from pre-hybridized strand. After addingmicrobeads, the solution produces bright fluorescence, while microbeads have no obvious signal. Genotypes are identified conveniently according to the fluorescence intensity of the solution. The method provides a simple and inexpensive strategy to detect point mutation. Moreover, this biosensor shows the linear relationship in the range of 1-40 nmol/L and reaches a detection limit of 0.3 nmol/L.
This report described a free-enzyme, convenient and inexpensive genotyping biosensor capable of detecting single nucleotide polymorphism at normal temperature based on the combination of toeholdmediated strand displacement reaction (toehold-SDR) and microbead-capture technique. The biosensor consists of a pre-hybridized strand formed by a reporter probe and a capture probe. In the presence of a mutant sequence, there is no toehold-mediated strand displacement and the reporter probe cannot be released from the pre-hybridized strand. Microbeads capture the fluorescent pre-hybridized strand through biotin-streptavidin interaction, so microbeads give out significant fluorescence signal, while there is no fluorescence in the solution. However, in the presence of a matched target, the strand displacement is effectively initiated and the reporter probe is released from pre-hybridized strand. After addingmicrobeads, the solution produces bright fluorescence, while microbeads have no obvious signal. Genotypes are identified conveniently according to the fluorescence intensity of the solution. The method provides a simple and inexpensive strategy to detect point mutation. Moreover, this biosensor shows the linear relationship in the range of 1-40 nmol/L and reaches a detection limit of 0.3 nmol/L.
2015, 26(8): 1036-1041
doi: 10.1016/j.cclet.2015.04.007
Abstract:
In this study, novel molecularly imprinted open porous membranes (MIOPMs) were prepared using the Pickering HIPEs template method and molecular imprinting technology for selective adsorption and separation of methyl 4-hydroxybenzoate (M4HB). The template M4HB, functional monomers, crosslinker and plastifier 2-ethylhexyl acrylate (2-EHA) were contained in the oil phase. Hydrophobic silica nanoparticles (HNP-SiO2) were employed as a stabilizer to establish stable W/O Pickering HIPEs with nonionic surfactant sorbitantrioleate (Span 85). The results of SEM and FTIR indicated that the optimal MIOPMs were prepared successfully and possessed open and interconnecting pores. Then, the MIOPMs were used as sorbents for M4HB. The correlation coefficient (R2) values for the Langmuir-Freundlich isotherm model and pseudo-second-order kineticmodel fitting to the adsorption equilibrium and kinetic data respectively were all higher than 0.95. The maximum adsorption capacity and the time of rapid adsorption for MIOPM4 were 4.146 mg g-1 and 100 min, respectively. In addition, the permeability separation factor of MIOPMs for M4HB compared to a structurally related analog methyl2-hydroxybenzoate (M2HB) could reach 3.122.
In this study, novel molecularly imprinted open porous membranes (MIOPMs) were prepared using the Pickering HIPEs template method and molecular imprinting technology for selective adsorption and separation of methyl 4-hydroxybenzoate (M4HB). The template M4HB, functional monomers, crosslinker and plastifier 2-ethylhexyl acrylate (2-EHA) were contained in the oil phase. Hydrophobic silica nanoparticles (HNP-SiO2) were employed as a stabilizer to establish stable W/O Pickering HIPEs with nonionic surfactant sorbitantrioleate (Span 85). The results of SEM and FTIR indicated that the optimal MIOPMs were prepared successfully and possessed open and interconnecting pores. Then, the MIOPMs were used as sorbents for M4HB. The correlation coefficient (R2) values for the Langmuir-Freundlich isotherm model and pseudo-second-order kineticmodel fitting to the adsorption equilibrium and kinetic data respectively were all higher than 0.95. The maximum adsorption capacity and the time of rapid adsorption for MIOPM4 were 4.146 mg g-1 and 100 min, respectively. In addition, the permeability separation factor of MIOPMs for M4HB compared to a structurally related analog methyl2-hydroxybenzoate (M2HB) could reach 3.122.
2015, 26(8): 1042-1045
doi: 10.1016/j.cclet.2015.05.048
Abstract:
In order to develop a sensor for the detection of toxic N2O molecules, the interaction of pristine and Aldoped BN nanosheets with an N2O molecule was investigated using density functional theory calculations. It was found that unlike the pristine sheet, the Al-doped sheet can effectively interact with the N2O molecule so that its electronic properties and conductivity are dramatically changed. Webelieve that replacing a B atom of the BN sheet with an Al atom may be a good strategy for improving the sensitivity of these nanosheets toward N2O, which cannot be trapped and detected by the pristine sheet.
In order to develop a sensor for the detection of toxic N2O molecules, the interaction of pristine and Aldoped BN nanosheets with an N2O molecule was investigated using density functional theory calculations. It was found that unlike the pristine sheet, the Al-doped sheet can effectively interact with the N2O molecule so that its electronic properties and conductivity are dramatically changed. Webelieve that replacing a B atom of the BN sheet with an Al atom may be a good strategy for improving the sensitivity of these nanosheets toward N2O, which cannot be trapped and detected by the pristine sheet.
2015, 26(8): 1046-1049
doi: 10.1016/j.cclet.2015.04.015
Abstract:
Exceedingly fast preparation of trifluoromethyl tertiary alcohols has been accomplished from methyl ketones and trifluoromethyl ketones under solvent free conditions by cross Aldol reaction. The reaction was achieved in the presence of common inorganic base by grinding method at ambient temperature to give β-trifluoromethyl-β-hydroxyl ketones in high yields (up to 95%).
Exceedingly fast preparation of trifluoromethyl tertiary alcohols has been accomplished from methyl ketones and trifluoromethyl ketones under solvent free conditions by cross Aldol reaction. The reaction was achieved in the presence of common inorganic base by grinding method at ambient temperature to give β-trifluoromethyl-β-hydroxyl ketones in high yields (up to 95%).
2015, 26(8): 1050-1053
doi: 10.1016/j.cclet.2015.04.014
Abstract:
A simple and efficient cascade Michael/cyclization reaction of 3-aminoindolin-2-ones with enones/enals was identified for the synthesis of potentially biologically active 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles], using DBU as an efficient catalyst and ethylene glycol as an environmentally benign solvent. More diverse 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles] analog libraries were prepared in good yields (up to 97%). The structure of 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles] was confirmed by mass spectrometry analysis, NMR analysis and single crystal X-ray diffraction. The main advantages of this method include the availability of startingmaterials, simple experimental operation, short reaction time, as well as high yields observed.
A simple and efficient cascade Michael/cyclization reaction of 3-aminoindolin-2-ones with enones/enals was identified for the synthesis of potentially biologically active 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles], using DBU as an efficient catalyst and ethylene glycol as an environmentally benign solvent. More diverse 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles] analog libraries were prepared in good yields (up to 97%). The structure of 3',4'-dihydrospiro[pyrrol-3,2'-oxindoles] was confirmed by mass spectrometry analysis, NMR analysis and single crystal X-ray diffraction. The main advantages of this method include the availability of startingmaterials, simple experimental operation, short reaction time, as well as high yields observed.
