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2014 Volume 25 Issue 12
2014, 25(12): 1511-1514
doi: 10.1016/j.cclet.2014.09.003
Abstract:
A titanosilicate Ti-ECNU-8 with a FER type sub-zeolite structure was developed by pots-synthesis and applied to the epoxdiation of alkenes with hydrogen peroxide. A controlled acid treatment on the pure silica layered precursor PLS-3 of FER topology gave rise to a sub-zeolite ECNU-8. Composed of a collection of FER sheets without an ordered stacking manner along layer related [1 0 0] direction, the structure of ECNU-8 was constructed by a reorientation of interlayer hydrogen bond moieties caused by partial removal of interlayer organic structure directing agent. ECNU-8 possessed an external surface area enlarged by ca. 30% in comparison to corresponding three-dimensional FER zeolite. Through a solid-gas reaction with TiCl4 vapor, tetrahedral Ti active sites were introduced into the framework. The resultant Ti-ECNU-8 retained the structural properties of ECNU-8, and exhibited an excellent catalytic performance for the epoxidation of cycloalkenes owing to the accessible Ti sites located in open reaction space.
A titanosilicate Ti-ECNU-8 with a FER type sub-zeolite structure was developed by pots-synthesis and applied to the epoxdiation of alkenes with hydrogen peroxide. A controlled acid treatment on the pure silica layered precursor PLS-3 of FER topology gave rise to a sub-zeolite ECNU-8. Composed of a collection of FER sheets without an ordered stacking manner along layer related [1 0 0] direction, the structure of ECNU-8 was constructed by a reorientation of interlayer hydrogen bond moieties caused by partial removal of interlayer organic structure directing agent. ECNU-8 possessed an external surface area enlarged by ca. 30% in comparison to corresponding three-dimensional FER zeolite. Through a solid-gas reaction with TiCl4 vapor, tetrahedral Ti active sites were introduced into the framework. The resultant Ti-ECNU-8 retained the structural properties of ECNU-8, and exhibited an excellent catalytic performance for the epoxidation of cycloalkenes owing to the accessible Ti sites located in open reaction space.
2014, 25(12): 1515-1519
doi: 10.1016/j.cclet.2014.09.018
Abstract:
An efficient synthetic pathway to 2-oxo-1,2-dihydropyridine-fused 1,3-diaza heterocycles from heterocyclic ketene aminals, phathalic anhydride and ethyl cyanacetate was established. This protocol involved aza-ene reaction/imine-enamine tautomerization/enamine-ester exchange/ring-opening reaction sequence.
An efficient synthetic pathway to 2-oxo-1,2-dihydropyridine-fused 1,3-diaza heterocycles from heterocyclic ketene aminals, phathalic anhydride and ethyl cyanacetate was established. This protocol involved aza-ene reaction/imine-enamine tautomerization/enamine-ester exchange/ring-opening reaction sequence.
2014, 25(12): 1520-1524
doi: 10.1016/j.cclet.2014.09.021
Abstract:
The Ru(bpy)32+ doped graphene oxide-silica composite film (Ru/GO-SiCF) was synthesized by one pot hydrolysis and condensation of tetraethylorthosilicate (TEOS) in the water-alcohol solution of graphene oxide and Ru(bpy)32+ at room temperature. The prepared Ru/GO-SiCF modified glassy carbon electrode (GCE) showed excellent electrochemiluminescence (ECL) behavior for the determination of tripropylamine (TPA) with high sensitivity and good stability. We expected this simple and novel material will find further application in construction of other targets sensors.
The Ru(bpy)32+ doped graphene oxide-silica composite film (Ru/GO-SiCF) was synthesized by one pot hydrolysis and condensation of tetraethylorthosilicate (TEOS) in the water-alcohol solution of graphene oxide and Ru(bpy)32+ at room temperature. The prepared Ru/GO-SiCF modified glassy carbon electrode (GCE) showed excellent electrochemiluminescence (ECL) behavior for the determination of tripropylamine (TPA) with high sensitivity and good stability. We expected this simple and novel material will find further application in construction of other targets sensors.
2014, 25(12): 1525-1530
doi: 10.1016/j.cclet.2014.09.016
Abstract:
We utilized the glycosyl acceptor tagging method with ionic liquid support for synthesis of the core segment of Clostridium botulinum C2 toxin ligand through a divergent synthetic strategy without chromatographic purification. The total yield was 57.1% and the reaction was completed in 10 h. The efficient ionic liquid supported glycosylation and purification procedure was applied for the synthesis of branched glucosamine-containing oligosaccharides for the first time, which expanded the scope of ionic liquid supported synthesis of biologically important oligosaccharides.
We utilized the glycosyl acceptor tagging method with ionic liquid support for synthesis of the core segment of Clostridium botulinum C2 toxin ligand through a divergent synthetic strategy without chromatographic purification. The total yield was 57.1% and the reaction was completed in 10 h. The efficient ionic liquid supported glycosylation and purification procedure was applied for the synthesis of branched glucosamine-containing oligosaccharides for the first time, which expanded the scope of ionic liquid supported synthesis of biologically important oligosaccharides.
2014, 25(12): 1531-1534
doi: 10.1016/j.cclet.2014.09.012
Abstract:
A minor diterpenoid with a novel carbon skeleton, secoeuphoractin (1), was isolated from an ethanol extract of the roots of Euphorbia micractina. Its structure including the absolute configuration was determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis, in combination with a plausible biosynthetic pathway associated with co-occurring diverse diterpenoids. This compound showed activity against HIV-1 replication with an IC50 value of 1.76±0.61 mmol/L.
A minor diterpenoid with a novel carbon skeleton, secoeuphoractin (1), was isolated from an ethanol extract of the roots of Euphorbia micractina. Its structure including the absolute configuration was determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis, in combination with a plausible biosynthetic pathway associated with co-occurring diverse diterpenoids. This compound showed activity against HIV-1 replication with an IC50 value of 1.76±0.61 mmol/L.
2014, 25(12): 1535-1539
doi: 10.1016/j.cclet.2014.09.013
Abstract:
Some novel cycloaddition reactions based on benzyne and olefins have been developed. These reactions were performed in the absence of a transition metal catalyst, and they displayed good yields. These cycloaddition reactions of benzyne with olefins provide effective routes for synthesizing benzocyclobutenes, biaryl compounds and 9,10-dihydrophenanthrene derivatives.
Some novel cycloaddition reactions based on benzyne and olefins have been developed. These reactions were performed in the absence of a transition metal catalyst, and they displayed good yields. These cycloaddition reactions of benzyne with olefins provide effective routes for synthesizing benzocyclobutenes, biaryl compounds and 9,10-dihydrophenanthrene derivatives.
2014, 25(12): 1540-1544
doi: 10.1016/j.cclet.2014.07.006
Abstract:
A substitution reaction of amines with alcohols for N-alkylated amines has been developed using inexpensive AlCl3 without any ligand or additive. Either aromatic or aliphatic amines and primary or secondary alcohols perform the AlCl3-mediated reaction smoothly to afford various N-alkylated amines in satisfactory yields.
A substitution reaction of amines with alcohols for N-alkylated amines has been developed using inexpensive AlCl3 without any ligand or additive. Either aromatic or aliphatic amines and primary or secondary alcohols perform the AlCl3-mediated reaction smoothly to afford various N-alkylated amines in satisfactory yields.
2014, 25(12): 1545-1549
doi: 10.1016/j.cclet.2014.06.021
Abstract:
A series of FTS/salicylic acid hybrids was designed and synthesized and their in vitro antitumor activities were evaluated. It was found that the anti-proliferation activities of hybrids were better than that of FTS. Compound 10a displayed the strongest antitumor activities with IC50 values of 5.72-9.76 mmol/L and selectively inhibited tumor cell proliferation. In addition, 10a induced tumor cell apoptosis in a dosedependent manner by up-regulating the expression of Bax and caspase-3 and down-regulating Bcl-2. Our findings suggest that these novel hybrids may hold a great promise as therapeutic agents for the intervention of human cancers.
A series of FTS/salicylic acid hybrids was designed and synthesized and their in vitro antitumor activities were evaluated. It was found that the anti-proliferation activities of hybrids were better than that of FTS. Compound 10a displayed the strongest antitumor activities with IC50 values of 5.72-9.76 mmol/L and selectively inhibited tumor cell proliferation. In addition, 10a induced tumor cell apoptosis in a dosedependent manner by up-regulating the expression of Bax and caspase-3 and down-regulating Bcl-2. Our findings suggest that these novel hybrids may hold a great promise as therapeutic agents for the intervention of human cancers.
2014, 25(12): 1550-1554
doi: 10.1016/j.cclet.2014.09.022
Abstract:
This work aimed at effectively utilizing the chemically depolymerized waste poly(ethylene terephthalate) (PET) fibers into useful products for the textile industry. PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst. The glycolysis product, bis(2-hydroxyethyl) terephthalate (BHET), was purified through repeated crystallization to get an average yield above 80%. Then, BHET was nitrated, reduced, and azotized to get diazonium salt. Finally, the produced diazonium salt was coupled with 1-(4-sulfophenyl)-3-methyl-5-pyrazolone to get azo dyestuff. The structures of BHET and azo dyestuff were identified by FTIR and 1H NMR spectra and elemental analysis. Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color. The performances of the dyestuff were described with dye uptake, color fastness, K/S, L*, a*, b*, and ΔE* values.
This work aimed at effectively utilizing the chemically depolymerized waste poly(ethylene terephthalate) (PET) fibers into useful products for the textile industry. PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst. The glycolysis product, bis(2-hydroxyethyl) terephthalate (BHET), was purified through repeated crystallization to get an average yield above 80%. Then, BHET was nitrated, reduced, and azotized to get diazonium salt. Finally, the produced diazonium salt was coupled with 1-(4-sulfophenyl)-3-methyl-5-pyrazolone to get azo dyestuff. The structures of BHET and azo dyestuff were identified by FTIR and 1H NMR spectra and elemental analysis. Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color. The performances of the dyestuff were described with dye uptake, color fastness, K/S, L*, a*, b*, and ΔE* values.
2014, 25(12): 1555-1558
doi: 10.1016/j.cclet.2014.07.011
Abstract:
Ethyl α-(dimethylaminomethylene)-2-cyanomethyl-4-phenylquinoline-3-carboxylate (2) as new synthons directed to 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitriles was obtained by the condensation of ethyl 2-cyanomethyl-4-phenylquinoline-3-carboxylate (1) and N,N-dimethylformamide dimethyl acetal (DMFDMA). Reaction of this enamine with primary amines (3) in HOAc-DMF at 120 ℃ then affords 2-substituted 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitrile derivatives (4) in good yields by a tandem addition-elimination-cyclization reaction.
Ethyl α-(dimethylaminomethylene)-2-cyanomethyl-4-phenylquinoline-3-carboxylate (2) as new synthons directed to 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitriles was obtained by the condensation of ethyl 2-cyanomethyl-4-phenylquinoline-3-carboxylate (1) and N,N-dimethylformamide dimethyl acetal (DMFDMA). Reaction of this enamine with primary amines (3) in HOAc-DMF at 120 ℃ then affords 2-substituted 1-oxo-1,2-dihydrobenzo[b][1,6]naphthyridine-4-carbonitrile derivatives (4) in good yields by a tandem addition-elimination-cyclization reaction.
2014, 25(12): 1559-1564
doi: 10.1016/j.cclet.2014.09.010
Abstract:
Aberrant DNAmethylation of CpG sites has been confirmed to be closely associated with carcinogenesis. Based on the hyperbranched rolling circle amplification (HRCA) and microarray techniques, a new method for qualitative detection of methylation was developed. In the present study, padlock probes hybridize the sample DNA at the methylation site to form a probe-DNA complex which is ligated and digested simultaneously by methylation specific enzymes. Only at the methylated CpG site is the padlock probe ligated successfully to form a circle template for the HRCA reaction. Utilizing the method of 3-dimensional polyacrylamide gel-based microarray, the HRCA product will be immobilized on the slide to form a DNA microarray, which can universally hybridize the Cy3-labeled oligonucleotide probe to detect the methylation status of CpG sites. To control the false positive signals, DNA ligase and temperature of ligation/digestion are optimized. Methylation status of four CpG sites located in P15, Ecadherin, hMLH1 andMGMT genes were analyzed successfully with this method and all the results were compatible with that of methylation-specific PCR. Our research proves that this method is simple and inexpensive, and could be applied as a high-throughput tool to qualitatively determine the methylation status of CpG sites.
Aberrant DNAmethylation of CpG sites has been confirmed to be closely associated with carcinogenesis. Based on the hyperbranched rolling circle amplification (HRCA) and microarray techniques, a new method for qualitative detection of methylation was developed. In the present study, padlock probes hybridize the sample DNA at the methylation site to form a probe-DNA complex which is ligated and digested simultaneously by methylation specific enzymes. Only at the methylated CpG site is the padlock probe ligated successfully to form a circle template for the HRCA reaction. Utilizing the method of 3-dimensional polyacrylamide gel-based microarray, the HRCA product will be immobilized on the slide to form a DNA microarray, which can universally hybridize the Cy3-labeled oligonucleotide probe to detect the methylation status of CpG sites. To control the false positive signals, DNA ligase and temperature of ligation/digestion are optimized. Methylation status of four CpG sites located in P15, Ecadherin, hMLH1 andMGMT genes were analyzed successfully with this method and all the results were compatible with that of methylation-specific PCR. Our research proves that this method is simple and inexpensive, and could be applied as a high-throughput tool to qualitatively determine the methylation status of CpG sites.
2014, 25(12): 1565-1568
doi: 10.1016/j.cclet.2014.07.002
Abstract:
To accelerate self-healing speed of epoxy materials, epoxy-SbF5 cure was introduced into the healing chemistry. Due to the high activity of SbF5, a milder SbF5-ethanol complex with improved processability was prepared, but it was still quite active and cannot be encapsulated by conventional encapsulation techniques like in situ polymerization. Accordingly, a novel route was proposed. Hollow silica microcapsules were firstly synthesized via sol-gel technique, which were then steeped in ethanol solution of SbF5-ethanol complex under vacuum, allowing infiltration of the latter into the capsules. The optimal formulation for creating the hollow silica capsules was studied in detail. Moreover, the results of optical pyrometry demonstrated that the encapsulated chemical retained its high reactivity toward the epoxy.
To accelerate self-healing speed of epoxy materials, epoxy-SbF5 cure was introduced into the healing chemistry. Due to the high activity of SbF5, a milder SbF5-ethanol complex with improved processability was prepared, but it was still quite active and cannot be encapsulated by conventional encapsulation techniques like in situ polymerization. Accordingly, a novel route was proposed. Hollow silica microcapsules were firstly synthesized via sol-gel technique, which were then steeped in ethanol solution of SbF5-ethanol complex under vacuum, allowing infiltration of the latter into the capsules. The optimal formulation for creating the hollow silica capsules was studied in detail. Moreover, the results of optical pyrometry demonstrated that the encapsulated chemical retained its high reactivity toward the epoxy.
2014, 25(12): 1569-1572
doi: 10.1016/j.cclet.2014.09.002
Abstract:
Li4Ti5O12 was synthesized by a facile gel-combustion method (GCM) with polyvinylpyrrolidone (PVP) as the polymer chelating agent and fuel. The structural and electrochemical properties of the sample were compared with the one prepared by the conventional solid-state reaction (SSR) through X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), charge-discharge measurements, and electrochemical impedance spectroscopy (EIS), respectively. The sub-microscale Li4Ti5O12 oxides, with a high phase purity and good stoichiometry, can be obtained by annealing at 800 ℃. The grain size is smaller than that of the samples that were power prepared by SSR. Lithium-ion batteries with a GCM Li4Ti5O12 anode exhibit excellent reversible capacities of 167.6, 160.7, 152.9, and 144.2 mAh/g, at the current densities of 0.5 C, 1 C, 3 C and 5 C, respectively. The excellent cycling and rate performance can be attributed to the smaller particle size, lower charge-transfer resistance and larger lithium ion diffusion coefficient. It is therefore concluded that GCM Li4Ti5O12 is a promising candidate for applications in highrate lithium ion batteries.
Li4Ti5O12 was synthesized by a facile gel-combustion method (GCM) with polyvinylpyrrolidone (PVP) as the polymer chelating agent and fuel. The structural and electrochemical properties of the sample were compared with the one prepared by the conventional solid-state reaction (SSR) through X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), charge-discharge measurements, and electrochemical impedance spectroscopy (EIS), respectively. The sub-microscale Li4Ti5O12 oxides, with a high phase purity and good stoichiometry, can be obtained by annealing at 800 ℃. The grain size is smaller than that of the samples that were power prepared by SSR. Lithium-ion batteries with a GCM Li4Ti5O12 anode exhibit excellent reversible capacities of 167.6, 160.7, 152.9, and 144.2 mAh/g, at the current densities of 0.5 C, 1 C, 3 C and 5 C, respectively. The excellent cycling and rate performance can be attributed to the smaller particle size, lower charge-transfer resistance and larger lithium ion diffusion coefficient. It is therefore concluded that GCM Li4Ti5O12 is a promising candidate for applications in highrate lithium ion batteries.
2014, 25(12): 1573-1576
doi: 10.1016/j.cclet.2014.07.013
Abstract:
Phytochemical investigation on the ethanol extract from the leaves of Aquilaria sinensis led to the isolation of five new benzophenone glycosides, aquilarinensides A-E (1-5). Their structures were elucidated by a combination of 1D and 2D NMR, HRMS, and chemical analysis.
Phytochemical investigation on the ethanol extract from the leaves of Aquilaria sinensis led to the isolation of five new benzophenone glycosides, aquilarinensides A-E (1-5). Their structures were elucidated by a combination of 1D and 2D NMR, HRMS, and chemical analysis.
2014, 25(12): 1577-1579
doi: 10.1016/j.cclet.2014.06.006
Abstract:
A new metabolite, named seimatoric acid (1), representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz., 2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone (2), (-)-phyllostine (3), (+)-epiepoxydon (4) and (+)-epoxydon monoacetate (5). Similarly one new benzoic acid derivative, named colletonoic acid (6) was isolated from the ethyl acetate fraction of Colletotrichum sp. The structures of the new compounds were elucidated by detailed 1HNMR, 13C NMR, COSY, HMQC,HMBCspectroscopic analysis, and HR-EI-MS. Seimatoric acid (1) was also isolated from another taxonomical unidentified fungal strain 4295 in our group. The structures of the known compounds were elucidated by their spectral data comparison to literature data. Preliminary studies showed that colletonoic acid (6) showed good antibacterial, antifungal, and antialgal activities.
A new metabolite, named seimatoric acid (1), representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz., 2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone (2), (-)-phyllostine (3), (+)-epiepoxydon (4) and (+)-epoxydon monoacetate (5). Similarly one new benzoic acid derivative, named colletonoic acid (6) was isolated from the ethyl acetate fraction of Colletotrichum sp. The structures of the new compounds were elucidated by detailed 1HNMR, 13C NMR, COSY, HMQC,HMBCspectroscopic analysis, and HR-EI-MS. Seimatoric acid (1) was also isolated from another taxonomical unidentified fungal strain 4295 in our group. The structures of the known compounds were elucidated by their spectral data comparison to literature data. Preliminary studies showed that colletonoic acid (6) showed good antibacterial, antifungal, and antialgal activities.
2014, 25(12): 1580-1582
doi: 10.1016/j.cclet.2014.07.012
Abstract:
An efficient three-component synthesis of 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles via a reaction between 3-methyl-1-phenyl-2-pyrazolin-5-one, aromatic aldehydes and malononitrile using tungstate sulfuric acid as a catalyst was described. Mild conditions, good to excellent yields, easily available catalyst and easy work-up are the key features of this method.
An efficient three-component synthesis of 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles via a reaction between 3-methyl-1-phenyl-2-pyrazolin-5-one, aromatic aldehydes and malononitrile using tungstate sulfuric acid as a catalyst was described. Mild conditions, good to excellent yields, easily available catalyst and easy work-up are the key features of this method.
2014, 25(12): 1583-1585
doi: 10.1016/j.cclet.2014.07.010
Abstract:
A facile and efficient protocol for the synthesis of sulfur substituted-cyclopyrophosphate of cIDPRE (PS1-cIDPRE) was developed. The key step was the cyclization process which was completed by the sulfur substituted cyclization precursor 1b via the one-pot phosphoramidite strategy.
A facile and efficient protocol for the synthesis of sulfur substituted-cyclopyrophosphate of cIDPRE (PS1-cIDPRE) was developed. The key step was the cyclization process which was completed by the sulfur substituted cyclization precursor 1b via the one-pot phosphoramidite strategy.
2014, 25(12): 1586-1590
doi: 10.1016/j.cclet.2014.07.008
Abstract:
Chiroptical properties including electronic circular dichroism (ECD) and optical rotatory dispersion (ORD) of artemisinin and artemether have been fully studied using quantum-chemical calculation based on time-dependent density functional theory. Both theoretical ECD and ORD of these two compounds were in good match with the experimental data. ECD spectrum of artemether could be totally attributed to the peroxide group, and that of artemisinin was an overlay of contribution from δ-lactone and peroxide moieties, which leading to a positive maximum at 260 nm. Our results showed that peroxide group could produce a broad ECD band in the far-UV region originated from electron transitions of HOMO→LUMO, HOMO 1→LUMO and HOMO 2→LUMO in the case of artemether. This work provided a theoretical interpretation of the ECD behavior of peroxide bond.
Chiroptical properties including electronic circular dichroism (ECD) and optical rotatory dispersion (ORD) of artemisinin and artemether have been fully studied using quantum-chemical calculation based on time-dependent density functional theory. Both theoretical ECD and ORD of these two compounds were in good match with the experimental data. ECD spectrum of artemether could be totally attributed to the peroxide group, and that of artemisinin was an overlay of contribution from δ-lactone and peroxide moieties, which leading to a positive maximum at 260 nm. Our results showed that peroxide group could produce a broad ECD band in the far-UV region originated from electron transitions of HOMO→LUMO, HOMO 1→LUMO and HOMO 2→LUMO in the case of artemether. This work provided a theoretical interpretation of the ECD behavior of peroxide bond.
2014, 25(12): 1591-1594
doi: 10.1016/j.cclet.2014.07.007
Abstract:
A simple and efficient procedure was developed for the synthesis of 11H(2H)-4-oxothiophene[3',4':6,5]pyrido[3,2-a]azulene-10-carboxylates (3) in moderate to good yields via the Gewald reaction of ethyl 1-cyanoacetyl-2-methoxyazulene-3-carboxylate (1) with carbonyl compounds (2) and elemental sulfur utilizing imidazole as catalyst. This reaction provides a new procedure for synthesis of pyridinone-fused azulenes.
A simple and efficient procedure was developed for the synthesis of 11H(2H)-4-oxothiophene[3',4':6,5]pyrido[3,2-a]azulene-10-carboxylates (3) in moderate to good yields via the Gewald reaction of ethyl 1-cyanoacetyl-2-methoxyazulene-3-carboxylate (1) with carbonyl compounds (2) and elemental sulfur utilizing imidazole as catalyst. This reaction provides a new procedure for synthesis of pyridinone-fused azulenes.
2014, 25(12): 1595-1600
doi: 10.1016/j.cclet.2014.06.026
Abstract:
Reusable acidic nickel oxide nanoparticles have been synthesized, characterized and applied as a catalyst to convert 2-aminoaryl ketones and β-ketoesters/ketones into the corresponding quinolines in good yields with high selectivity. This could serve as a simple and convenient procedure for the Friedlander annulations.
Reusable acidic nickel oxide nanoparticles have been synthesized, characterized and applied as a catalyst to convert 2-aminoaryl ketones and β-ketoesters/ketones into the corresponding quinolines in good yields with high selectivity. This could serve as a simple and convenient procedure for the Friedlander annulations.
2014, 25(12): 1601-1606
doi: 10.1016/j.cclet.2014.09.009
Abstract:
Catalyst-free copolymerization of ethyl diazoacetate (EDA) with carbethoxycarbene (CEC) has been achieved through two approaches: microwave irradiation and enzyme-assisted (Novozyme-435) system. The structure of the copolymer was characterized by MALDI-TOF MS (m/z from 2000 to 2450), which suggested that the main chain of the copolymer consisted of -CH(COOEt)-and -N55N-CH(COOEt)-frameworks. Fourier transform infrared (FTIR) spectrometry, elemental analysis, and Raman spectrometry proved the incorporation of azo group in the copolymer. The results indicated that the CEC radicals were generated under microwave irradiation (with or without Novozyme-435) from EDA. The mechanism study described that the generation speed of CEC radical was faster than its polymerization, and the excess CEC radicals improved the activity of the N2C1 group, thus inducing some EDA molecules as radicals. The two kinds of radicals co-coupled to result in poly(CEC-co-EDA) through the C1/N2C1 copolymerization, but the homopolymerization of CEC radical occurred quicker than its cocoupling with activated EDA
Catalyst-free copolymerization of ethyl diazoacetate (EDA) with carbethoxycarbene (CEC) has been achieved through two approaches: microwave irradiation and enzyme-assisted (Novozyme-435) system. The structure of the copolymer was characterized by MALDI-TOF MS (m/z from 2000 to 2450), which suggested that the main chain of the copolymer consisted of -CH(COOEt)-and -N55N-CH(COOEt)-frameworks. Fourier transform infrared (FTIR) spectrometry, elemental analysis, and Raman spectrometry proved the incorporation of azo group in the copolymer. The results indicated that the CEC radicals were generated under microwave irradiation (with or without Novozyme-435) from EDA. The mechanism study described that the generation speed of CEC radical was faster than its polymerization, and the excess CEC radicals improved the activity of the N2C1 group, thus inducing some EDA molecules as radicals. The two kinds of radicals co-coupled to result in poly(CEC-co-EDA) through the C1/N2C1 copolymerization, but the homopolymerization of CEC radical occurred quicker than its cocoupling with activated EDA
2014, 25(12): 1607-1610
doi: 10.1016/j.cclet.2014.06.022
Abstract:
Electrochemical oxidation of 4-methyl catechol (1a) is investigated in the presence of 1,3-indandione (3) as nucleophile in phosphate buffer solution (0.2 mol/L, pH 6) mixed with ethanol as organic green solvent (50/50) using cyclic voltammetry and controlled-potential coulometry. The results indicated that quinones derived from electro-oxidation of 1a, participated in a 1,4-Michael addition reaction with 1,3-indandione (3) under ECCEmechanism. In this direction, a new bis-quinone was synthesized in high yield and good purity using a facile and convenient electrochemical pathway by carbon anode electrodes in an undivided cell.
Electrochemical oxidation of 4-methyl catechol (1a) is investigated in the presence of 1,3-indandione (3) as nucleophile in phosphate buffer solution (0.2 mol/L, pH 6) mixed with ethanol as organic green solvent (50/50) using cyclic voltammetry and controlled-potential coulometry. The results indicated that quinones derived from electro-oxidation of 1a, participated in a 1,4-Michael addition reaction with 1,3-indandione (3) under ECCEmechanism. In this direction, a new bis-quinone was synthesized in high yield and good purity using a facile and convenient electrochemical pathway by carbon anode electrodes in an undivided cell.
2014, 25(12): 1611-1614
doi: 10.1016/j.cclet.2014.06.025
Abstract:
The fluorine-substituted benzoate ester rod-shaped liquid crystals containing an azobenzene side chain linked with terminal double bonds were synthesized and characterized. The mesophase and photoswitching properties were determined by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and UV-visible spectrometry. The rod-shaped compound 4a having an odd number of carbon atoms in the alkyl chains exhibits nematic phase and SmA type phase whereas compound 4b having an even number of carbon atoms showed only nematic phase. Both fluorinecontaining compounds 4c and 4d showed only SmA type phases. The photoswitching properties of these compounds showed a rate of trans to cis isomerization ranging 19-20 s, whereas reverse process took around 230 min in solution. These materials may be ideal in the field of optically rewritable applications where both on and off rates should be crucial.
The fluorine-substituted benzoate ester rod-shaped liquid crystals containing an azobenzene side chain linked with terminal double bonds were synthesized and characterized. The mesophase and photoswitching properties were determined by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and UV-visible spectrometry. The rod-shaped compound 4a having an odd number of carbon atoms in the alkyl chains exhibits nematic phase and SmA type phase whereas compound 4b having an even number of carbon atoms showed only nematic phase. Both fluorinecontaining compounds 4c and 4d showed only SmA type phases. The photoswitching properties of these compounds showed a rate of trans to cis isomerization ranging 19-20 s, whereas reverse process took around 230 min in solution. These materials may be ideal in the field of optically rewritable applications where both on and off rates should be crucial.
2014, 25(12): 1615-1619
doi: 10.1016/j.cclet.2014.07.014
Abstract:
CuO nanoparticles were synthesized at a relatively low temperature (80 ℃) for 2 h using polyethylene glycol-glycerol mixture which acts as a capping agent. A detailed characterization of the synthesized nanomaterials were performed utilizing X-ray diffraction (XRD), infra-red spectroscopy (IR), thermogravimetric analysis (TGA-DTA), transmission electron microscopy (TEM), photoluminescence (PL) by studying its crystalline phase, vibrational mode, thermal analysis, morphology and photoluminescence properties. The effect of annealing on the as-prepared nanoparticles were studied and compared with their corresponding bulk counterpart. The synthesized nanoparticles have been screened for in vitro cytotoxicity (IC50) studies against the human cervical adenocarcinoma cell line (HeLa) using MTT assay methods. The as-prepared nanoparticle inhibits the proliferation of this HeLa cell. The standard disc diffusion method has been used to study the antibacterial activity of the samples against the human pathogenic bacteria Escherichia coli (MTCC 729), Proteus mirabilis (MTCC 425) and Klebsiella pneumoniae subsp. pneumoniae (MTCC 432). The results have been compared with the positive control antibiotic gentamycin. The synthesized nanoparticles would provide a potential alternative to antibiotics for controlling some of the microorganisms causing urolithiasis.
CuO nanoparticles were synthesized at a relatively low temperature (80 ℃) for 2 h using polyethylene glycol-glycerol mixture which acts as a capping agent. A detailed characterization of the synthesized nanomaterials were performed utilizing X-ray diffraction (XRD), infra-red spectroscopy (IR), thermogravimetric analysis (TGA-DTA), transmission electron microscopy (TEM), photoluminescence (PL) by studying its crystalline phase, vibrational mode, thermal analysis, morphology and photoluminescence properties. The effect of annealing on the as-prepared nanoparticles were studied and compared with their corresponding bulk counterpart. The synthesized nanoparticles have been screened for in vitro cytotoxicity (IC50) studies against the human cervical adenocarcinoma cell line (HeLa) using MTT assay methods. The as-prepared nanoparticle inhibits the proliferation of this HeLa cell. The standard disc diffusion method has been used to study the antibacterial activity of the samples against the human pathogenic bacteria Escherichia coli (MTCC 729), Proteus mirabilis (MTCC 425) and Klebsiella pneumoniae subsp. pneumoniae (MTCC 432). The results have been compared with the positive control antibiotic gentamycin. The synthesized nanoparticles would provide a potential alternative to antibiotics for controlling some of the microorganisms causing urolithiasis.
2014, 25(12): 1620-1624
doi: 10.1016/j.cclet.2014.06.028
Abstract:
A novel copolymer with fluorescence properties in mesoporous silica SBA-15 was prepared via a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and “click” chemistry. A sufficient amount of peroxide groups were introduced into mesoporous silica SBA-15 channel pores and were further used to initiate the RAFT polymerization of styrene and 4-vinylbenzyl azide, resulting in SBA-15 supported polystyrene-co-poly(4-vinylbenzyl azide) copolymer (PS-co-PVBA/SBA-15) hybrid material. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry analysis (TGA), N2 adsorption-desorption isotherms and X-ray diffraction (XRD), respectively. The results show that the styrene and 4-vinylbenzyl azide had copolymerized inside mesoporous silica SBA-15. Subsequently, Npropargyl-carbazole (PC) was connected to PS-co-PVBA/SBA-15 hybrid material via “click” reaction, resulting in PS-co-PVBC/SBA-15 with carbazole side groups hybrid material. The fluorescence spectrum is dominated by a broad band from 350 nm to 400 nm in narrow region and the maximum peak is 362 nm, indicating the characteristic absorption of the carbazole group of PS-co-PVBC/SBA-15 hybrid material.
A novel copolymer with fluorescence properties in mesoporous silica SBA-15 was prepared via a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and “click” chemistry. A sufficient amount of peroxide groups were introduced into mesoporous silica SBA-15 channel pores and were further used to initiate the RAFT polymerization of styrene and 4-vinylbenzyl azide, resulting in SBA-15 supported polystyrene-co-poly(4-vinylbenzyl azide) copolymer (PS-co-PVBA/SBA-15) hybrid material. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry analysis (TGA), N2 adsorption-desorption isotherms and X-ray diffraction (XRD), respectively. The results show that the styrene and 4-vinylbenzyl azide had copolymerized inside mesoporous silica SBA-15. Subsequently, Npropargyl-carbazole (PC) was connected to PS-co-PVBA/SBA-15 hybrid material via “click” reaction, resulting in PS-co-PVBC/SBA-15 with carbazole side groups hybrid material. The fluorescence spectrum is dominated by a broad band from 350 nm to 400 nm in narrow region and the maximum peak is 362 nm, indicating the characteristic absorption of the carbazole group of PS-co-PVBC/SBA-15 hybrid material.
2014, 25(12): 1625-1629
doi: 10.1016/j.cclet.2014.06.018
Abstract:
Thin-film microextraction (TFME), a new geometry for solid-phase microextraction, has become an attractive sample-preparation technique. Compared to other microextraction approaches, the sensitivity of this technique was enhanced without sacrificing the sampling time due to the high surface area-tovolume ratio together with the increase of extraction-phase volume. In this paper, a new TFME method based on poly(vinylidene fluoride) membrane was developed for the extraction of benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron and teflubenzuron) from water samples followed by their determination with high performance liquid chromatography-diode array detection. Under the optimal conditions, good linearity was observed over the concentration range of 0.5-100.0 ng/mL with correlation coefficient greater than 0.9994. The limits of detection (S/N = 3) of the method for the target analytes were 0.1 ng/mL. Mean recoveries ranged from 87.7% to 103.9% with relative standard deviations lower than 6.5%. The results indicated that the developed TFMEmethod is simple, efficient, and cost effective.
Thin-film microextraction (TFME), a new geometry for solid-phase microextraction, has become an attractive sample-preparation technique. Compared to other microextraction approaches, the sensitivity of this technique was enhanced without sacrificing the sampling time due to the high surface area-tovolume ratio together with the increase of extraction-phase volume. In this paper, a new TFME method based on poly(vinylidene fluoride) membrane was developed for the extraction of benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron and teflubenzuron) from water samples followed by their determination with high performance liquid chromatography-diode array detection. Under the optimal conditions, good linearity was observed over the concentration range of 0.5-100.0 ng/mL with correlation coefficient greater than 0.9994. The limits of detection (S/N = 3) of the method for the target analytes were 0.1 ng/mL. Mean recoveries ranged from 87.7% to 103.9% with relative standard deviations lower than 6.5%. The results indicated that the developed TFMEmethod is simple, efficient, and cost effective.
2014, 25(12): 1630-1634
doi: 10.1016/j.cclet.2014.07.005
Abstract:
MWCNTs-C-PO3H2 has been used as an efficient, heterogeneous and reusable nanocatalyst for synthesis of acylals from aldehydes under solvent-free conditions at room temperature. A wide range of aldehydes was studied and corresponding products were obtained in good to excellent yields in short reaction times. Nanocatalyst can be easily recovered by centrifuge and reused for subsequent reactions for at least five times without deterioration in catalytic activity. The major advantages of the present method are high yields, short reaction time, recyclable catalyst and solvent-free reaction conditions at room temperature.
MWCNTs-C-PO3H2 has been used as an efficient, heterogeneous and reusable nanocatalyst for synthesis of acylals from aldehydes under solvent-free conditions at room temperature. A wide range of aldehydes was studied and corresponding products were obtained in good to excellent yields in short reaction times. Nanocatalyst can be easily recovered by centrifuge and reused for subsequent reactions for at least five times without deterioration in catalytic activity. The major advantages of the present method are high yields, short reaction time, recyclable catalyst and solvent-free reaction conditions at room temperature.
2014, 25(12): 1635-1638
doi: 10.1016/j.cclet.2014.06.019
Abstract:
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/chitin nanocrystals (CNC) composite scaffolds were synthesized by the salt leaching and thermally induced phase separation (TIPS) technique. The scaffolds have porous structures with macro-pores (100-300 mm in diameters) and micro-pores (10 mm). The surface characteristics of the scaffolds were characterized by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurement, and the mechanical properties were investigated by a compression test. Human adipose-derived stem cells (hADSCs) were seeded onto the PHBV/CNC scaffolds and in vitro cell culture results showed that the composite scaffolds enhanced the hADSCs adhesion, which implies that the material may have potential application in tissue engineering.
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/chitin nanocrystals (CNC) composite scaffolds were synthesized by the salt leaching and thermally induced phase separation (TIPS) technique. The scaffolds have porous structures with macro-pores (100-300 mm in diameters) and micro-pores (10 mm). The surface characteristics of the scaffolds were characterized by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurement, and the mechanical properties were investigated by a compression test. Human adipose-derived stem cells (hADSCs) were seeded onto the PHBV/CNC scaffolds and in vitro cell culture results showed that the composite scaffolds enhanced the hADSCs adhesion, which implies that the material may have potential application in tissue engineering.
2014, 25(12): 1639-1642
doi: 10.1016/j.cclet.2014.06.020
Abstract:
In this work a PVC membrane electrode based on bis(N-3-methyl phenyl salicylidenaminato)copper(Ⅱ) as ionophore was prepared. The electrode was tested by inorganic anions and showed good selectivity for thiocyanate ion. This sensor showed Nerstian behavior with a slope of a 59.3 mV per decade at 25 ℃. The proposed electrode exhibited a wide linear range from 1.0×10-6 mol/L to 1.0×10-1 mol/L with a detection limit of 5.0×10-7 mol/L. The electrode response was independent of pH in the range of 4.0-10.0. The response time is about 9-21 s, and the electrode can be used for over 60 days without considerable deterioration. The prepared sensor was applied as an indicator electrode in potentiometric titration of SCN- with Ag+ ion and to determine the thiocyanate in samples of urine and saliva.
In this work a PVC membrane electrode based on bis(N-3-methyl phenyl salicylidenaminato)copper(Ⅱ) as ionophore was prepared. The electrode was tested by inorganic anions and showed good selectivity for thiocyanate ion. This sensor showed Nerstian behavior with a slope of a 59.3 mV per decade at 25 ℃. The proposed electrode exhibited a wide linear range from 1.0×10-6 mol/L to 1.0×10-1 mol/L with a detection limit of 5.0×10-7 mol/L. The electrode response was independent of pH in the range of 4.0-10.0. The response time is about 9-21 s, and the electrode can be used for over 60 days without considerable deterioration. The prepared sensor was applied as an indicator electrode in potentiometric titration of SCN- with Ag+ ion and to determine the thiocyanate in samples of urine and saliva.
2014, 25(12): 1643-1647
doi: 10.1016/j.cclet.2014.09.005
Abstract:
In this work, an effective, task specific, dicationic, podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction. Moreover, to broaden the scope and decreasing the serious limitations of preparation methods of organic azides, a simple green procedure for the preparation of alkyl azides, the fundamental starting materials in click reactions, from alcohols under solvent-free conditions and microwave irradiation has been reported, for the first time.
In this work, an effective, task specific, dicationic, podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction. Moreover, to broaden the scope and decreasing the serious limitations of preparation methods of organic azides, a simple green procedure for the preparation of alkyl azides, the fundamental starting materials in click reactions, from alcohols under solvent-free conditions and microwave irradiation has been reported, for the first time.
2014, 25(12): 1648-1652
doi: 10.1016/j.cclet.2014.09.001
Abstract:
Xiao-Xu-Ming decoction (XXMD) was a traditional Chinese prescription and first recorded in “Bei Ji Qian Jin Yao Fang”. It has been widely used to treat theoplegia and the sequel of theoplegia in China. In the present work, high-performance liquid chromatography coupled with high resolution mass spectrometry (HPLC-HRMS) combined with the mass spectral tree similarity filter technique (MTSF) was used to rapidly discover and identify the compounds of the active fraction of XXMD. A total of 3362 compounds were automatically detected by HPLC-HRMS, and final 68 compounds were identified in the active fraction of XXMD, including 14 templated compounds (reference compounds), 50 related compounds fished by MTSF technique, and 4 unrelated compounds identified by manual method. This study successfully applied MTSF technology for the first time to discover and identify the components of Chinese prescription. The results demonstrated that MTSF technique should be useful to the discovery and identification of compounds in Chinese prescription. This study also proved that MTSF can be applied to the targeted phytochemical separation.
Xiao-Xu-Ming decoction (XXMD) was a traditional Chinese prescription and first recorded in “Bei Ji Qian Jin Yao Fang”. It has been widely used to treat theoplegia and the sequel of theoplegia in China. In the present work, high-performance liquid chromatography coupled with high resolution mass spectrometry (HPLC-HRMS) combined with the mass spectral tree similarity filter technique (MTSF) was used to rapidly discover and identify the compounds of the active fraction of XXMD. A total of 3362 compounds were automatically detected by HPLC-HRMS, and final 68 compounds were identified in the active fraction of XXMD, including 14 templated compounds (reference compounds), 50 related compounds fished by MTSF technique, and 4 unrelated compounds identified by manual method. This study successfully applied MTSF technology for the first time to discover and identify the components of Chinese prescription. The results demonstrated that MTSF technique should be useful to the discovery and identification of compounds in Chinese prescription. This study also proved that MTSF can be applied to the targeted phytochemical separation.
