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2015 Volume 26 Issue 1
2015, 26(1): 1-5
doi: 10.1016/j.cclet.2014.10.019
Abstract:
A series of new hexahydroimidazo[1,2-a]pyridine derivatives were synthesized via convenient and practical three-component reactions. Preliminary bioassays showed that majority of the target compounds exhibited moderate to excellent insecticidal activity against cowpea aphids (Aphis craccivora). Among them, compound 9l demonstrated significant activity with LC50 value of 0.00918 mmol/L which was about 3.8-fold higher than that of imidacloprid (IMI). Furthermore, the study of stereostructure-activity relationship of four isomers of 9k indicated that configuration played a key role in insecticidal activity of these compounds.
A series of new hexahydroimidazo[1,2-a]pyridine derivatives were synthesized via convenient and practical three-component reactions. Preliminary bioassays showed that majority of the target compounds exhibited moderate to excellent insecticidal activity against cowpea aphids (Aphis craccivora). Among them, compound 9l demonstrated significant activity with LC50 value of 0.00918 mmol/L which was about 3.8-fold higher than that of imidacloprid (IMI). Furthermore, the study of stereostructure-activity relationship of four isomers of 9k indicated that configuration played a key role in insecticidal activity of these compounds.
2015, 26(1): 6-10
doi: 10.1016/j.cclet.2014.10.022
Abstract:
A new highly efficient and reusable Cu(I)-MOF has been developed for the synthesis of propargylamine compounds via the three-component reaction of secondary amines, alkynes, and aromatic aldehydes under solvent-free conditions. The desired propargylamines were obtained in good to excellent yields with a low catalyst loading. The catalyst may be recovered and reused for up to 5 cycles without major loss of activity. This protocol has the advantages of excellent yields, low catalyst loading, and catalyst recyclability.
A new highly efficient and reusable Cu(I)-MOF has been developed for the synthesis of propargylamine compounds via the three-component reaction of secondary amines, alkynes, and aromatic aldehydes under solvent-free conditions. The desired propargylamines were obtained in good to excellent yields with a low catalyst loading. The catalyst may be recovered and reused for up to 5 cycles without major loss of activity. This protocol has the advantages of excellent yields, low catalyst loading, and catalyst recyclability.
2015, 26(1): 11-14
doi: 10.1016/j.cclet.2014.09.007
Abstract:
A highly efficient copper-catalyzed approach to form amide bonds from formamides and carboxylic acids was developed. This protocol shows broad substrate scopes and high yields in the presence of 1 mol% catalyst and 4.0 equiv. formamides.
A highly efficient copper-catalyzed approach to form amide bonds from formamides and carboxylic acids was developed. This protocol shows broad substrate scopes and high yields in the presence of 1 mol% catalyst and 4.0 equiv. formamides.
2015, 26(1): 15-20
doi: 10.1016/j.cclet.2014.10.003
Abstract:
In this paper, we present a simple method by combining surface wrinkling and template replication to create a series of hierarchical structures on polydimethylsiloxane (PDMS) elastomer. The primary stable lined patterns are formed by duplicating commercialized compact disk and digital versatile disk with PDMS. The secondary microscale patterns are from surface wrinkling, which is elicited by oxygen plasma (OP) treatment of the prestrained PDMS stamp followed with the prestrain release. By systematically varying the OP exposure duration, the prestrain, and the angle (θ) between the primary pattern orientation and the prestrain direction, we obtain highly ordered well-organized composite patterns from different patterning techniques and with different length scales and mechanical stabilities.
In this paper, we present a simple method by combining surface wrinkling and template replication to create a series of hierarchical structures on polydimethylsiloxane (PDMS) elastomer. The primary stable lined patterns are formed by duplicating commercialized compact disk and digital versatile disk with PDMS. The secondary microscale patterns are from surface wrinkling, which is elicited by oxygen plasma (OP) treatment of the prestrained PDMS stamp followed with the prestrain release. By systematically varying the OP exposure duration, the prestrain, and the angle (θ) between the primary pattern orientation and the prestrain direction, we obtain highly ordered well-organized composite patterns from different patterning techniques and with different length scales and mechanical stabilities.
2015, 26(1): 21-25
doi: 10.1016/j.cclet.2014.10.002
Abstract:
Benzoylformamide (BFA) derivatives are proposed as new photocaged bases with good solubility in epoxy resin. Initially their structures were confirmed by 1HNMR, 13C NMR, and elemental analysis. Next, we detail their thermal stability, solubility behavior, and photolysis products. Furthermore, the model photo-latent anion polymerization (AP) of epoxide system in the presence of BFA-dBA (N,N-dibenzyl-2-oxo-2-phenylacetamide) as a photocaged base has been investigated, and excellent photopolymerization profile is obtained.
Benzoylformamide (BFA) derivatives are proposed as new photocaged bases with good solubility in epoxy resin. Initially their structures were confirmed by 1HNMR, 13C NMR, and elemental analysis. Next, we detail their thermal stability, solubility behavior, and photolysis products. Furthermore, the model photo-latent anion polymerization (AP) of epoxide system in the presence of BFA-dBA (N,N-dibenzyl-2-oxo-2-phenylacetamide) as a photocaged base has been investigated, and excellent photopolymerization profile is obtained.
2015, 26(1): 26-30
doi: 10.1016/j.cclet.2014.10.009
Abstract:
4-(Succinimido)-1-butane sulfonic acid as an efficient and reusable Brönsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions. The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid. This method has the advantages of high yield, clean reaction, simple methodology and short reaction time. The catalyst could be recycled without significant loss of activity.
4-(Succinimido)-1-butane sulfonic acid as an efficient and reusable Brönsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions. The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid. This method has the advantages of high yield, clean reaction, simple methodology and short reaction time. The catalyst could be recycled without significant loss of activity.
2015, 26(1): 31-35
doi: 10.1016/j.cclet.2014.10.005
Abstract:
One novel organic-inorganic hybrid supramolecular assemblies [(NDPA)·(18-crown-6)]2+·(DMA)+·3ClO4- (1), has been successfully constructed through the prominent strategies of crystal engineering (NDPA = N,N-dimethyl-1,4-phenylenediamine, DMA = dimethylamine), and characterized by IR, powder XRD and single crystal X-ray diffraction. In the structure, the supramolecular organic cations and inorganic ClO4- anions are arranged alternately and linked by N-O···H hydrogen bonds. It is worthy to note that the ClO4- are linked to form one-dimensional inorganic chain through strong N- H···O hydrogen bonds along b-axis. There is no distinct dielectric anomaly in the temperaturedependent and frequency-dependent dielectric constant curves, suggesting that no phase transition exists within the measured temperature range (120-420 K). The relative displacement of cations and anions, the turned polarization of molecular electric moment and macrocyclic molecule rotator are the main factors to determine the trend of dielectric constant.
One novel organic-inorganic hybrid supramolecular assemblies [(NDPA)·(18-crown-6)]2+·(DMA)+·3ClO4- (1), has been successfully constructed through the prominent strategies of crystal engineering (NDPA = N,N-dimethyl-1,4-phenylenediamine, DMA = dimethylamine), and characterized by IR, powder XRD and single crystal X-ray diffraction. In the structure, the supramolecular organic cations and inorganic ClO4- anions are arranged alternately and linked by N-O···H hydrogen bonds. It is worthy to note that the ClO4- are linked to form one-dimensional inorganic chain through strong N- H···O hydrogen bonds along b-axis. There is no distinct dielectric anomaly in the temperaturedependent and frequency-dependent dielectric constant curves, suggesting that no phase transition exists within the measured temperature range (120-420 K). The relative displacement of cations and anions, the turned polarization of molecular electric moment and macrocyclic molecule rotator are the main factors to determine the trend of dielectric constant.
2015, 26(1): 36-38
doi: 10.1016/j.cclet.2014.10.026
Abstract:
Chloramphenicol is an antibiotic and one of the potential contaminants in honey. Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey. In this work, an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive, reliable and higher throughput analysis was developed. With the methylcellulose-immobilized reversed-phase column, sugars in a honey sample were efficiently removed in 1 min. As a result, the limit of quantitation of chloramphenicol was 20 pg/mL (0.2 mg/kg honey).
Chloramphenicol is an antibiotic and one of the potential contaminants in honey. Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey. In this work, an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive, reliable and higher throughput analysis was developed. With the methylcellulose-immobilized reversed-phase column, sugars in a honey sample were efficiently removed in 1 min. As a result, the limit of quantitation of chloramphenicol was 20 pg/mL (0.2 mg/kg honey).
2015, 26(1): 39-42
doi: 10.1016/j.cclet.2014.10.014
Abstract:
In this work, a novel bisbenzimidazolylpyridine-functionalized fluorescent epoxy resin was synthesized for organophosphate pesticide detection. The epoxy resin was characterized by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and fluorescence spectroscopy. After loading with Eu(Ⅲ) ions, the epoxy resin showed a strong fluorescence emission. The fluorescence emission was observed to be instantaneously quenched when exposed to trace amount of diethyl chlorophosphate in solution. The Stern-Volmer quenching constants Ksv for quenching at 617 nm was determined to be 0.377×103 L/mol. This sensitive emission-quenching function and easy processing nature of the polymeric support enable the resin to be a promising chemosensor candidate for the detection of organophosphates.
In this work, a novel bisbenzimidazolylpyridine-functionalized fluorescent epoxy resin was synthesized for organophosphate pesticide detection. The epoxy resin was characterized by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and fluorescence spectroscopy. After loading with Eu(Ⅲ) ions, the epoxy resin showed a strong fluorescence emission. The fluorescence emission was observed to be instantaneously quenched when exposed to trace amount of diethyl chlorophosphate in solution. The Stern-Volmer quenching constants Ksv for quenching at 617 nm was determined to be 0.377×103 L/mol. This sensitive emission-quenching function and easy processing nature of the polymeric support enable the resin to be a promising chemosensor candidate for the detection of organophosphates.
2015, 26(1): 43-46
doi: 10.1016/j.cclet.2014.08.001
Abstract:
Inspired by biological systems that have the inherent skill to generate considerable bioelectricity from the salt content in fluids with highly selective ion channels and pumps on cellmembranes, herein, a fully abiotic, single glass conical nanopores energy-harvesting is demonstrated. Ion current rectification (ICR) in negatively charged glass conical nanopores is shown to be controlled by the electrolyte concentration gradient depending on the direction of ion diffusion. The degree of ICR is enhanced with the increasing forward concentration difference. An unusual rectification inversion is observed when the concentration gradient is reversely applied. The maximum power output with the individual nanopore approaches 104 pW. This facile and cost-efficient energy-harvesting system has the potential to power tiny biomedical devices or construct future clean-energy recovery plants.
Inspired by biological systems that have the inherent skill to generate considerable bioelectricity from the salt content in fluids with highly selective ion channels and pumps on cellmembranes, herein, a fully abiotic, single glass conical nanopores energy-harvesting is demonstrated. Ion current rectification (ICR) in negatively charged glass conical nanopores is shown to be controlled by the electrolyte concentration gradient depending on the direction of ion diffusion. The degree of ICR is enhanced with the increasing forward concentration difference. An unusual rectification inversion is observed when the concentration gradient is reversely applied. The maximum power output with the individual nanopore approaches 104 pW. This facile and cost-efficient energy-harvesting system has the potential to power tiny biomedical devices or construct future clean-energy recovery plants.
2015, 26(1): 47-49
doi: 10.1016/j.cclet.2014.10.001
Abstract:
Graphene oxide (GO) has attracted extensive attention due to its unique properties and potential applications. Here, we report the investigation of GO nanosheets as a stationary phase for capillary gas chromatographic (GC) separations. The GO column, fabricated by a new one-step coating approach, showed average McReynolds constants of 308, suggesting the mediumpolar nature of the GC stationary phase. The GO stationary phase achieves good separation for analytes of different types with good peak shapes, especially for H-bonding analytes, such as alcohols and amines. The different retention behaviors of GO stationary phase from the conventional stationary phase may originate from its multiple interactions with analytes, involving H-bonding, dipole-dipole, π-π stacking and dispersive interactions. Moreover, GO column showed good separation reproducibility with relative standard deviation (RSD%) less than 0.24% (n = 5) on retention times of analytes.
Graphene oxide (GO) has attracted extensive attention due to its unique properties and potential applications. Here, we report the investigation of GO nanosheets as a stationary phase for capillary gas chromatographic (GC) separations. The GO column, fabricated by a new one-step coating approach, showed average McReynolds constants of 308, suggesting the mediumpolar nature of the GC stationary phase. The GO stationary phase achieves good separation for analytes of different types with good peak shapes, especially for H-bonding analytes, such as alcohols and amines. The different retention behaviors of GO stationary phase from the conventional stationary phase may originate from its multiple interactions with analytes, involving H-bonding, dipole-dipole, π-π stacking and dispersive interactions. Moreover, GO column showed good separation reproducibility with relative standard deviation (RSD%) less than 0.24% (n = 5) on retention times of analytes.
2015, 26(1): 50-54
doi: 10.1016/j.cclet.2014.09.006
Abstract:
A series of novel thiazolidinedione-triazole hybrids were synthesized by one pot reaction between thiazolidine-2,4-dione, substituted aryl aldehydes, propargyl bromide and substituted aryl azides using piperidine, CuSO4·5H2O and sodium ascorbate as catalysts in PEG-400 as a highly efficient and green media. These thiazolidinedione-triazole hybrids were subjected to in vitro antibacterial activity against four strains namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and antifungal activity against two fungal strains namely, Aspergillus niger and Aspergillus flavus.
A series of novel thiazolidinedione-triazole hybrids were synthesized by one pot reaction between thiazolidine-2,4-dione, substituted aryl aldehydes, propargyl bromide and substituted aryl azides using piperidine, CuSO4·5H2O and sodium ascorbate as catalysts in PEG-400 as a highly efficient and green media. These thiazolidinedione-triazole hybrids were subjected to in vitro antibacterial activity against four strains namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and antifungal activity against two fungal strains namely, Aspergillus niger and Aspergillus flavus.
2015, 26(1): 55-57
doi: 10.1016/j.cclet.2014.09.019
Abstract:
Wereport a practical and highly efficient protocol for the arylation of pyridine N-oxides with arylboronic acid through palladium-catalyzed Suzuki reaction in water. This ligand-free Suzuki reaction is performed in the presence of diisopropylamine and gives 2- or 3-arylated pyridyl N-oxide derivatives in good to excellent yields within 1 h.
Wereport a practical and highly efficient protocol for the arylation of pyridine N-oxides with arylboronic acid through palladium-catalyzed Suzuki reaction in water. This ligand-free Suzuki reaction is performed in the presence of diisopropylamine and gives 2- or 3-arylated pyridyl N-oxide derivatives in good to excellent yields within 1 h.
2015, 26(1): 58-62
doi: 10.1016/j.cclet.2014.10.021
Abstract:
Density functional theory (DFT) method was used to explore the origin of the regioselectivity of Cocatalyzed hydroacylation of 1,3-dienes. The reaction of 2-methyl-1,3-butadiene and benzaldehyde with 1,3-bis(diphenylphosphino)propane ligand was chosen as the model reaction. The energies of the intermediates and transition states in the stages of oxidative cyclization, β-H elimination and C-H reductive elimination were investigated. Computational results show that β-H elimination is the ratedetermining step for the whole catalytic cycle. C1-Selective oxidative cyclization is favored over C4-selective oxidative cyclization. Besides, C4-selective oxidative cyclization is kinetically disfavored than all the steps in C1-hydroacylation mechanisms, consistent with the experimentally obtained C1- selective hydroacylation products. Analyzing the reason for such observation, we suggest that both electronic and steric effects contribute to the C1-selectivity. On the electronic aspect, C1 is more electron rich than C4 due to the methyl group on C2, which makes the electrophilic attack of aldehyde carbon on C1 more favorable. On the steric aspect, the methyl group locates farther from the ligands in the transition state of C1-selective oxidative cyclization than in that of C4-selective oxidative cyclization.
Density functional theory (DFT) method was used to explore the origin of the regioselectivity of Cocatalyzed hydroacylation of 1,3-dienes. The reaction of 2-methyl-1,3-butadiene and benzaldehyde with 1,3-bis(diphenylphosphino)propane ligand was chosen as the model reaction. The energies of the intermediates and transition states in the stages of oxidative cyclization, β-H elimination and C-H reductive elimination were investigated. Computational results show that β-H elimination is the ratedetermining step for the whole catalytic cycle. C1-Selective oxidative cyclization is favored over C4-selective oxidative cyclization. Besides, C4-selective oxidative cyclization is kinetically disfavored than all the steps in C1-hydroacylation mechanisms, consistent with the experimentally obtained C1- selective hydroacylation products. Analyzing the reason for such observation, we suggest that both electronic and steric effects contribute to the C1-selectivity. On the electronic aspect, C1 is more electron rich than C4 due to the methyl group on C2, which makes the electrophilic attack of aldehyde carbon on C1 more favorable. On the steric aspect, the methyl group locates farther from the ligands in the transition state of C1-selective oxidative cyclization than in that of C4-selective oxidative cyclization.
2015, 26(1): 63-68
doi: 10.1016/j.cclet.2014.10.008
Abstract:
We designed and synthesized a series of 2-thioxo-4-thiazolidinone derivatives and evaluated them on peroxisome proliferator activated receptor γ(PPARγ) binding activities. Through the biological assays, compounds 18 and 38 were highlighted with Ki values of 12.15 nmol/L and 14.46 nmol/L, respectively. Then structure-activity relationship (SAR) was analyzed to screen privileged structural modifications. Moreover, molecular fitting of these compounds onto the approved drug Rosiglitazone in the PPARγ ligand binding domain was performed to elucidate the SAR and explore potential receptor-ligand interactions. These results demonstrate that the 2-thioxo-4-thiazolidinones can be considered as new promising molecular probes with excellent binding activities to PPARγ.
We designed and synthesized a series of 2-thioxo-4-thiazolidinone derivatives and evaluated them on peroxisome proliferator activated receptor γ(PPARγ) binding activities. Through the biological assays, compounds 18 and 38 were highlighted with Ki values of 12.15 nmol/L and 14.46 nmol/L, respectively. Then structure-activity relationship (SAR) was analyzed to screen privileged structural modifications. Moreover, molecular fitting of these compounds onto the approved drug Rosiglitazone in the PPARγ ligand binding domain was performed to elucidate the SAR and explore potential receptor-ligand interactions. These results demonstrate that the 2-thioxo-4-thiazolidinones can be considered as new promising molecular probes with excellent binding activities to PPARγ.
2015, 26(1): 69-72
doi: 10.1016/j.cclet.2014.10.011
Abstract:
Two new 1-(6'-O-acyl-β-D-glucopyranosyl)pyridinium-3-carboxylates, lonijaponinicotinosides A (1) and B (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic 1-β-D-glucopyranosylpyridinium-3-carboxylate.
Two new 1-(6'-O-acyl-β-D-glucopyranosyl)pyridinium-3-carboxylates, lonijaponinicotinosides A (1) and B (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic 1-β-D-glucopyranosylpyridinium-3-carboxylate.
2015, 26(1): 73-76
doi: 10.1016/j.cclet.2014.10.018
Abstract:
A novel Pd-catalyzed tandem reaction involving hydroalkynylation, isomerization, Diels-Alder cycloaddition and aromatization reaction to produce phthalan derivatives in moderate yields is reported. The reaction is atom economical and occurs in a highly ordered fashion. The reaction mechanism is discussed.
A novel Pd-catalyzed tandem reaction involving hydroalkynylation, isomerization, Diels-Alder cycloaddition and aromatization reaction to produce phthalan derivatives in moderate yields is reported. The reaction is atom economical and occurs in a highly ordered fashion. The reaction mechanism is discussed.
Yttrium-catalyzed heterocyclic formation via aerobic oxygenation: A green approach to benzothiazoles
2015, 26(1): 77-80
doi: 10.1016/j.cclet.2014.10.017
Abstract:
The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.
The YCl3-catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.
2015, 26(1): 81-84
doi: 10.1016/j.cclet.2014.11.001
Abstract:
A facile, rapid and solvent-free method for the conversion of acids and dihalomethane to the corresponding methylene diesters (acylals) using microwave as activators or assistor, is reported. This method is particularly powerful for the diesterification of carboxylic acids, which afford methylene diesters in good to excellent yields (up to >99%). When the intermediate is trapped, a "double successive SN2 reactions" mechanism is proved.
A facile, rapid and solvent-free method for the conversion of acids and dihalomethane to the corresponding methylene diesters (acylals) using microwave as activators or assistor, is reported. This method is particularly powerful for the diesterification of carboxylic acids, which afford methylene diesters in good to excellent yields (up to >99%). When the intermediate is trapped, a "double successive SN2 reactions" mechanism is proved.
2015, 26(1): 85-88
doi: 10.1016/j.cclet.2014.10.015
Abstract:
A ring-opening process of 4-imino-1,3-thiazetidin-2-ones with NH2OH·HCl was described for the first time. Two different scaffolds of imidodicarbonic diamide were obtained selectively in good yields in the presence of organic base. The obtained imidodicarbonic diamides were demonstrated by X-ray diffraction analysis.
A ring-opening process of 4-imino-1,3-thiazetidin-2-ones with NH2OH·HCl was described for the first time. Two different scaffolds of imidodicarbonic diamide were obtained selectively in good yields in the presence of organic base. The obtained imidodicarbonic diamides were demonstrated by X-ray diffraction analysis.
2015, 26(1): 89-92
doi: 10.1016/j.cclet.2014.09.015
Abstract:
A novel and efficient method for the preparation of nucleoside 50-tetraphosphates has been developed by coupling nucleoside 5'-phosphoropiperidates with triphosphate reagent in the presence of 4, 5-dicyanoimidazole (DCI) activator. Further coupling of the nucleoside 5'-tetraphosphates with nucleoside 50-phosphoropiperidates via the P(V)-N activation strategy provided a reliable synthetic method for both symmetrical and asymmetrical dinucleoside pentaphosphates.
A novel and efficient method for the preparation of nucleoside 50-tetraphosphates has been developed by coupling nucleoside 5'-phosphoropiperidates with triphosphate reagent in the presence of 4, 5-dicyanoimidazole (DCI) activator. Further coupling of the nucleoside 5'-tetraphosphates with nucleoside 50-phosphoropiperidates via the P(V)-N activation strategy provided a reliable synthetic method for both symmetrical and asymmetrical dinucleoside pentaphosphates.
2015, 26(1): 93-99
doi: 10.1016/j.cclet.2014.10.024
Abstract:
Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 (RR195) in a semi-batch reactor. The decolorization of RR195 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant (k) obtained with different operational parameters was compared. Our results showed that RR195 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries (sodium carbonate and sodium chloride) that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.
Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 (RR195) in a semi-batch reactor. The decolorization of RR195 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant (k) obtained with different operational parameters was compared. Our results showed that RR195 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries (sodium carbonate and sodium chloride) that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.
2015, 26(1): 100-102
doi: 10.1016/j.cclet.2014.10.010
Abstract:
Novel Co(Ⅱ) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL1-CoL4 were synthesized and characterized. Their oxygenation constants (ln KO2) and thermodynamic parameters (ΔH°, ΔS°) were measured. And their catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) was investigated. The enhancement of O2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.
Novel Co(Ⅱ) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL1-CoL4 were synthesized and characterized. Their oxygenation constants (ln KO2) and thermodynamic parameters (ΔH°, ΔS°) were measured. And their catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) was investigated. The enhancement of O2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.
2015, 26(1): 103-107
doi: 10.1016/j.cclet.2014.09.020
Abstract:
A facile synthesis of suvorexant, an orexin receptor antagonist, is described. The key intermediate 6 was prepared from R-3-aminobutyric acid through protection, condensation, deprotection, cyclization, and hydrogenation steps. The title product was obtained with a total yield of 31% (>99% ee) after eight linear steps using commercially available raw materials.
A facile synthesis of suvorexant, an orexin receptor antagonist, is described. The key intermediate 6 was prepared from R-3-aminobutyric acid through protection, condensation, deprotection, cyclization, and hydrogenation steps. The title product was obtained with a total yield of 31% (>99% ee) after eight linear steps using commercially available raw materials.
2015, 26(1): 108-112
doi: 10.1016/j.cclet.2014.10.020
Abstract:
The present work describes a facile, one-pot three component synthesis of a series of 3-[(4,5-diphenyl-2-substituted aryl/heteryl)-1H-imidazol-1-yl]-1H-1,2,4-triazole-5-carboxylic acid derivatives M(1-15). Benzil, aromatic aldehydes and 3-amino-1,2,4-triazole-5-carboxylic acid was refluxed in ethanol using cerric ammonium nitrate (CAN) as a catalyst to give the title compounds in good yields. The compounds were evaluated for their in vitro antifungal and antibacterial activity. Compounds M1, M9, and M15 were found to be equipotent against Candida albicans when compared with fluconazole. Compounds M2, M5, and M14 showed higher activity against Streptococcus pneumoniae, Escherichia coli and Streptococcus pyogenes, respectively, compared with ampicillin. Docking study of the newly synthesized compounds was performed, and the results showed good bindingmode in the active sites of C. albicans enzyme cytochrome P450 lanosterol 14α-demethylase. The results of in vitro antifungal activity and docking study showed that synthesized compounds had potential antifungal activity and can be further optimized and developed as a lead compound.
The present work describes a facile, one-pot three component synthesis of a series of 3-[(4,5-diphenyl-2-substituted aryl/heteryl)-1H-imidazol-1-yl]-1H-1,2,4-triazole-5-carboxylic acid derivatives M(1-15). Benzil, aromatic aldehydes and 3-amino-1,2,4-triazole-5-carboxylic acid was refluxed in ethanol using cerric ammonium nitrate (CAN) as a catalyst to give the title compounds in good yields. The compounds were evaluated for their in vitro antifungal and antibacterial activity. Compounds M1, M9, and M15 were found to be equipotent against Candida albicans when compared with fluconazole. Compounds M2, M5, and M14 showed higher activity against Streptococcus pneumoniae, Escherichia coli and Streptococcus pyogenes, respectively, compared with ampicillin. Docking study of the newly synthesized compounds was performed, and the results showed good bindingmode in the active sites of C. albicans enzyme cytochrome P450 lanosterol 14α-demethylase. The results of in vitro antifungal activity and docking study showed that synthesized compounds had potential antifungal activity and can be further optimized and developed as a lead compound.
2015, 26(1): 113-117
doi: 10.1016/j.cclet.2014.09.008
Abstract:
Chemical modification of penicillin β-lactam ring was made. Six thiazolidine amides were produced through N4-C7 β-lactam ring opening of penicillin V methyl ester with various aliphatic, aromatic, and heterocyclic primary amines. Five 8-hydroxypenillic acid derivatives with side chains of methyl, propyl, benzyl, and diethylaminoethyl groups were yielded via β-lactam ring rearrangement from 6-aminopenicillanic acid (6-APA). Parallel synthetic methods were used for the alkylation of 8-hydroxypenillic acid and β-lactam ring opening of penicillin V methyl ester. The biological activities of the compounds were evaluated.
Chemical modification of penicillin β-lactam ring was made. Six thiazolidine amides were produced through N4-C7 β-lactam ring opening of penicillin V methyl ester with various aliphatic, aromatic, and heterocyclic primary amines. Five 8-hydroxypenillic acid derivatives with side chains of methyl, propyl, benzyl, and diethylaminoethyl groups were yielded via β-lactam ring rearrangement from 6-aminopenicillanic acid (6-APA). Parallel synthetic methods were used for the alkylation of 8-hydroxypenillic acid and β-lactam ring opening of penicillin V methyl ester. The biological activities of the compounds were evaluated.
2015, 26(1): 118-120
doi: 10.1016/j.cclet.2014.10.016
Abstract:
Since the PI3K signaling pathway is the most commonly activated in human cancers, inhibition of PI3K is a promising approach to cancer therapy. In this study, a series of 2-methyl-5-nitrobenzeneacylhydrazones were designed and synthesized. All the new derivatives were tested by p110α enzymatic and Rh30 cellular assays. Further enzyme selectivity profiling proved that 6e and 7 were potential selective PI3K inhibitors.
Since the PI3K signaling pathway is the most commonly activated in human cancers, inhibition of PI3K is a promising approach to cancer therapy. In this study, a series of 2-methyl-5-nitrobenzeneacylhydrazones were designed and synthesized. All the new derivatives were tested by p110α enzymatic and Rh30 cellular assays. Further enzyme selectivity profiling proved that 6e and 7 were potential selective PI3K inhibitors.
2015, 26(1): 121-123
doi: 10.1016/j.cclet.2014.08.005
Abstract:
Two new myrinsol diterpenoids, euphordracunculins A (1) and B (2), together with three known analogues, euphorprolitherin B (3), proliferins A (4) and B (5), were isolated from the petroleum ether extract of the aerial parts of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and ESI-MS) and comparison with data reported in the literature.
Two new myrinsol diterpenoids, euphordracunculins A (1) and B (2), together with three known analogues, euphorprolitherin B (3), proliferins A (4) and B (5), were isolated from the petroleum ether extract of the aerial parts of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and ESI-MS) and comparison with data reported in the literature.
2015, 26(1): 124-128
doi: 10.1016/j.cclet.2014.09.023
Abstract:
SnO2 hollow nanospheres were successfully synthesized via a facile one-step solvothermal method. Characterizations show that the as-prepared SnO2 spheres are of hollow structure with a diameter at around 50 nm, and especially, the shell of the spheres is assembled by single layer SnO2 nanocrystals. The surface area of the material reaches up to 202.5 m2/g. As an anode material for Li ion batteries, the sample exhibited improved electrochemical performance compared with commercial SnO2 particles. After cycled at high current rate of 0.5 C, 1 C and 0.5 C for 20 cycles, respectively, the electrode can maintain a capacity of 509 mAh/g. The suitable shell thickness/diameter ratio endows the good structural stability of the material during cycling, which promises the excellent cycling performance of the electrode. The large surface area and the ultra thin shell ensure the high rate performance of the material.
SnO2 hollow nanospheres were successfully synthesized via a facile one-step solvothermal method. Characterizations show that the as-prepared SnO2 spheres are of hollow structure with a diameter at around 50 nm, and especially, the shell of the spheres is assembled by single layer SnO2 nanocrystals. The surface area of the material reaches up to 202.5 m2/g. As an anode material for Li ion batteries, the sample exhibited improved electrochemical performance compared with commercial SnO2 particles. After cycled at high current rate of 0.5 C, 1 C and 0.5 C for 20 cycles, respectively, the electrode can maintain a capacity of 509 mAh/g. The suitable shell thickness/diameter ratio endows the good structural stability of the material during cycling, which promises the excellent cycling performance of the electrode. The large surface area and the ultra thin shell ensure the high rate performance of the material.
2015, 26(1): 129-132
doi: 10.1016/j.cclet.2014.09.025
Abstract:
A simple, water-soluble, Fe3+-selective fluorescent probe, derived from rhodamine B, was synthesized and characterized. The probe exhibits a fluorescence response toward Fe3+ with acceptable sensitivity and selectivity and even facilitates visual or naked-eye detection of Fe3+. The experiment results show that the response of the probe to Fe3+ is pH-independent over a wide range of 4.0-10.0. In addition, fluorescence microscopic imaging experiments have proven that the probe is cell permeable and can be used for monitoring intracellular Fe3+ in living cells.
A simple, water-soluble, Fe3+-selective fluorescent probe, derived from rhodamine B, was synthesized and characterized. The probe exhibits a fluorescence response toward Fe3+ with acceptable sensitivity and selectivity and even facilitates visual or naked-eye detection of Fe3+. The experiment results show that the response of the probe to Fe3+ is pH-independent over a wide range of 4.0-10.0. In addition, fluorescence microscopic imaging experiments have proven that the probe is cell permeable and can be used for monitoring intracellular Fe3+ in living cells.
2015, 26(1): 133-136
doi: 10.1016/j.cclet.2014.11.022
Abstract:
BiOCl nanostructures including microspheres, microflowers, microplates, and nanoplates, have been synthesized by a simple solvothermal method using bismuth nitrate and sodium chloride as raw materials without adding any additives. Structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicated that the as-prepared microspheres and microflowers were composed of nanosheets. Although with different shape and lateral size, the nanoplates and microplates were all single-crystalline plates with exposed {001} facets. It was found that the volume ratio of polyethylene glycol 400 and H2O in the solvent played a key role in the morphology of the products, and the possible growth mechanism was also discussed. The photocatalytic measurements indicated that the BiOCl samples exhibit good photocatalytic properties towards Rhodamine B.
BiOCl nanostructures including microspheres, microflowers, microplates, and nanoplates, have been synthesized by a simple solvothermal method using bismuth nitrate and sodium chloride as raw materials without adding any additives. Structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicated that the as-prepared microspheres and microflowers were composed of nanosheets. Although with different shape and lateral size, the nanoplates and microplates were all single-crystalline plates with exposed {001} facets. It was found that the volume ratio of polyethylene glycol 400 and H2O in the solvent played a key role in the morphology of the products, and the possible growth mechanism was also discussed. The photocatalytic measurements indicated that the BiOCl samples exhibit good photocatalytic properties towards Rhodamine B.
2015, 26(1): 137-140
doi: 10.1016/j.cclet.2014.10.013
Abstract:
An air and moisture stable ruthenium(Ⅲ) formate complex [Ru(HCO2)Cl2]n has been synthesized and examined in the epoxidation of substituted styrenes. X-ray crystallographic data of this complex were determined and showed that the formate ligand coordinates to the ruthenium centers in μ2-η2 fashion (syn, syn). Its asymmetric unit contains one Ru(Ⅲ) ion together with the half of a formate ligand and one chloride anion, which are bridged between the metal centers, forming a 1-D chain coordination polymer. This electron deficient helical coordination polymer was employed in the epoxidation of parafluorostyrene, affording the epoxide product in 92% yield. Natural chirality of this coordination polymer is applicable in asymmetric epoxidation reactions.
An air and moisture stable ruthenium(Ⅲ) formate complex [Ru(HCO2)Cl2]n has been synthesized and examined in the epoxidation of substituted styrenes. X-ray crystallographic data of this complex were determined and showed that the formate ligand coordinates to the ruthenium centers in μ2-η2 fashion (syn, syn). Its asymmetric unit contains one Ru(Ⅲ) ion together with the half of a formate ligand and one chloride anion, which are bridged between the metal centers, forming a 1-D chain coordination polymer. This electron deficient helical coordination polymer was employed in the epoxidation of parafluorostyrene, affording the epoxide product in 92% yield. Natural chirality of this coordination polymer is applicable in asymmetric epoxidation reactions.
2015, 26(1): 141-144
doi: 10.1016/j.cclet.2014.09.011
Abstract:
CdS sensitized NiO electrode was used as the photoactive cathode in a photoelectrochemical cell for water splitting, avoiding the use of a sacrificial electron donor. Photocurrent increment under visible light irradiation was observed after integration of [Co(dmgH)2(4-Me-py)Cl] (1) to the photocathode, suggesting 1 could accept electrons from photoexcited CdS for water reduction and NiO could move the holes in the valence band of CdS to anode for water oxidation.
CdS sensitized NiO electrode was used as the photoactive cathode in a photoelectrochemical cell for water splitting, avoiding the use of a sacrificial electron donor. Photocurrent increment under visible light irradiation was observed after integration of [Co(dmgH)2(4-Me-py)Cl] (1) to the photocathode, suggesting 1 could accept electrons from photoexcited CdS for water reduction and NiO could move the holes in the valence band of CdS to anode for water oxidation.
2015, 26(1): 145-148
doi: 10.1016/j.cclet.2014.09.024
Abstract:
The pyridazine hexafluorophosphate [C4H5N2]+[PF6]- (1) undergoes a reversible phase transition around 140 K, which was confirmed by the DSC measurement. Variable-temperature crystal structures determined at 293 K and 93 K show that the compound crystallizes in the same space group P21/c, indicating that 1 undergoes an iso-structural phase transition. As the temperature decreases, dielectric measurement of the title compound shows no significant change around the phase transition temperature. Classic hydrogen bonds are found between molecules at 293 K and 93 K with similar packing arrangement. Themost distinct difference between the low temperature and room temperature structures is the order-disorder transition of the hexafluorophosphate anion, which is probably the driving force of the phase transition.
The pyridazine hexafluorophosphate [C4H5N2]+[PF6]- (1) undergoes a reversible phase transition around 140 K, which was confirmed by the DSC measurement. Variable-temperature crystal structures determined at 293 K and 93 K show that the compound crystallizes in the same space group P21/c, indicating that 1 undergoes an iso-structural phase transition. As the temperature decreases, dielectric measurement of the title compound shows no significant change around the phase transition temperature. Classic hydrogen bonds are found between molecules at 293 K and 93 K with similar packing arrangement. Themost distinct difference between the low temperature and room temperature structures is the order-disorder transition of the hexafluorophosphate anion, which is probably the driving force of the phase transition.
2015, 26(1): 149-151
doi: 10.1016/j.cclet.2014.09.017
Abstract:
Novel tricyclic fluoroquinolones, [1,2,4]triazolo[3,4-h][1,8]naphthyridine-8-one-7-carboxylic acid derivatives 4a-4h bearing carrying a functional Mannich-base moiety at the C-8 position, were synthesized and evaluated for their antimicrobial activity. The results showed that some compounds with a piperazine side chain exhibited comparable or better antibacterial activity than comparator cirprofloxacin. Furthermore, the targeted compounds also displayed a broad spectrum of activity against resistant strains including both Gram-negative and Gram-positive bacteria. In particular, compound 4h showed an MIC of 0.25 μg/mL in antibacterial assay against multiple drug-resistant Escherichia coli, which represents an about 30-fold increase of potency compared to ciprofloxacin. Thus, their excellent antibacterial activity against resistant strains suggests that triazole-fused fluoroquinolones warrant further optimization as novel anti-infective chemotherapies.
Novel tricyclic fluoroquinolones, [1,2,4]triazolo[3,4-h][1,8]naphthyridine-8-one-7-carboxylic acid derivatives 4a-4h bearing carrying a functional Mannich-base moiety at the C-8 position, were synthesized and evaluated for their antimicrobial activity. The results showed that some compounds with a piperazine side chain exhibited comparable or better antibacterial activity than comparator cirprofloxacin. Furthermore, the targeted compounds also displayed a broad spectrum of activity against resistant strains including both Gram-negative and Gram-positive bacteria. In particular, compound 4h showed an MIC of 0.25 μg/mL in antibacterial assay against multiple drug-resistant Escherichia coli, which represents an about 30-fold increase of potency compared to ciprofloxacin. Thus, their excellent antibacterial activity against resistant strains suggests that triazole-fused fluoroquinolones warrant further optimization as novel anti-infective chemotherapies.
2015, 26(1): 152-156
doi: 10.1016/j.cclet.2014.10.007
Abstract:
An efficient and high-yielding synthesis of N2-arylaminopyrimidine-5-carbonitrile derivatives starting from arylamines and 2-methylthio-pyrimidine-5-carbonitrile derivatives has been developed in the presence of cesium carbonate as basic reagent. This new protocol showed high chemical tolerance for a range of functional groups, and only the methylthio substituent on C2 of the pyrimidine ring was replaced with arylamine derivatives under the reaction conditions.
An efficient and high-yielding synthesis of N2-arylaminopyrimidine-5-carbonitrile derivatives starting from arylamines and 2-methylthio-pyrimidine-5-carbonitrile derivatives has been developed in the presence of cesium carbonate as basic reagent. This new protocol showed high chemical tolerance for a range of functional groups, and only the methylthio substituent on C2 of the pyrimidine ring was replaced with arylamine derivatives under the reaction conditions.
2015, 26(1): 157-159
doi: 10.1016/j.cclet.2014.08.004
Abstract:
The aim of this study was to investigate the chemical compositions of chalk dust and examine the adverse effects of fine chalk particle matters (PM2.5) on rat alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of chalk particles were analyzed using quantitative energydispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs exposed to chalk PM2.5 was measured by luminol-dependent chemiluminescence (CL). The results showed that (1) Chalk dust was mainly composed of gypsum (CaSO4), calcite (CaCO3)/dolomite (CaMg(CO3)2), and organic adhesives; (2) Fine chalk particles induced the AM production of CL, which was inhibited by about 90% by diphenyleneiodonium chloride (DPI). Based on these results, we showed that cytotoxicity of chalk PM2.5 may be related to the reactive oxygen species (ROS) generation.
The aim of this study was to investigate the chemical compositions of chalk dust and examine the adverse effects of fine chalk particle matters (PM2.5) on rat alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of chalk particles were analyzed using quantitative energydispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs exposed to chalk PM2.5 was measured by luminol-dependent chemiluminescence (CL). The results showed that (1) Chalk dust was mainly composed of gypsum (CaSO4), calcite (CaCO3)/dolomite (CaMg(CO3)2), and organic adhesives; (2) Fine chalk particles induced the AM production of CL, which was inhibited by about 90% by diphenyleneiodonium chloride (DPI). Based on these results, we showed that cytotoxicity of chalk PM2.5 may be related to the reactive oxygen species (ROS) generation.
2015, 26(1): 160-166
doi: 10.1016/j.cclet.2014.09.004
Abstract:
An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled, single strand DNA (NH2-ssDNA) onto a self-assembled diazo-thiourea and gold nanoparticles modified Au electrode (diazo-thiourea/GNM/Au). Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA (ssDNA) onto the electrode surface. Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH2-ssDNA onto the electrode surface. The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry (DPV) using methylene blue (MB) as a well-known electrochemical hybridization indicator. The linear range for the determination of complementary target ssDNA is from 9.5(±0.1)×10-13 mol/L to 1.2(±0.2)×10-9 mol/L with a detection limit of 1.2(±0.1)×10-13mol/L.
An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled, single strand DNA (NH2-ssDNA) onto a self-assembled diazo-thiourea and gold nanoparticles modified Au electrode (diazo-thiourea/GNM/Au). Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA (ssDNA) onto the electrode surface. Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH2-ssDNA onto the electrode surface. The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry (DPV) using methylene blue (MB) as a well-known electrochemical hybridization indicator. The linear range for the determination of complementary target ssDNA is from 9.5(±0.1)×10-13 mol/L to 1.2(±0.2)×10-9 mol/L with a detection limit of 1.2(±0.1)×10-13mol/L.
