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2013 Volume 24 Issue 12
2013, 24(12): 1037-1040
Abstract:
Partially graphitic micro- and mesoporous carbon microspheres (GMMCMs) were synthesized using hydrothermal emulsion polymerization followed by KOH activation and catalytic graphitization. The resulting GMMCMs show micro- and mesopores with a specific surface area of 1113 m2/g, regular spherical shape with diameters of 0.5-1.0 mm and a partially graphitic structure with a low internal resistance of 0.34 Ω. The graphitic carbons as electrode for supercapacitor exhibit a fast ion-transport and rapid charge-discharge feature, and a high-rate electrochemical performance. The typical GMMCM electrode shows a specific capacitance of 220 F/g at 1.0 A/g, and 185 F/g under a high current density of 20.0 A/g in a 6 mol/L KOH electrolyte.
Partially graphitic micro- and mesoporous carbon microspheres (GMMCMs) were synthesized using hydrothermal emulsion polymerization followed by KOH activation and catalytic graphitization. The resulting GMMCMs show micro- and mesopores with a specific surface area of 1113 m2/g, regular spherical shape with diameters of 0.5-1.0 mm and a partially graphitic structure with a low internal resistance of 0.34 Ω. The graphitic carbons as electrode for supercapacitor exhibit a fast ion-transport and rapid charge-discharge feature, and a high-rate electrochemical performance. The typical GMMCM electrode shows a specific capacitance of 220 F/g at 1.0 A/g, and 185 F/g under a high current density of 20.0 A/g in a 6 mol/L KOH electrolyte.
2013, 24(12): 1041-1044
Abstract:
A series of CoMo/Al2O3 catalysts for selective hydrodesulfurization (HDS) of gasoline were studied with Raman spectroscopy, a powerfulmethod that creates specific signals for the states and the distributions of oxidic precursors and sulfided active phases. The higher the Mo and Co, the lower the tetrahedrally coordinated molybdate, and the higher the polymolybdate. But the amount of polymolybdate decreased when CoMoO4 appeared. Cobalt-promoted polymolybdate was the precursor, and its relative content correlated well with the HDS selectivity. For sulfided catalysts, adding the cobalt-promoter led to local distortion-disorder of the MoS2 structure and the formation of a CoMoS phase. This method can provide important information for designing new industrial selective-HDS catalysts.
A series of CoMo/Al2O3 catalysts for selective hydrodesulfurization (HDS) of gasoline were studied with Raman spectroscopy, a powerfulmethod that creates specific signals for the states and the distributions of oxidic precursors and sulfided active phases. The higher the Mo and Co, the lower the tetrahedrally coordinated molybdate, and the higher the polymolybdate. But the amount of polymolybdate decreased when CoMoO4 appeared. Cobalt-promoted polymolybdate was the precursor, and its relative content correlated well with the HDS selectivity. For sulfided catalysts, adding the cobalt-promoter led to local distortion-disorder of the MoS2 structure and the formation of a CoMoS phase. This method can provide important information for designing new industrial selective-HDS catalysts.
2013, 24(12): 1045-1048
Abstract:
A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, 1H NMR, 13C NMR and HRMS.
A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, 1H NMR, 13C NMR and HRMS.
2013, 24(12): 1049-1052
Abstract:
A new cytotoxic pyrrolidinoindoline diketopiperazine dimer, cristatumin E (1), was isolated from the fermentation broth of the algal fungus Eurotium herbariorum HT-2 associated with the marine algae, Enteromorpha prolifera. The structure was determined by spectroscopic analyses and Marfey's amino acid analysis. Cristatumin E (1) showed cytotoxicity against K562 tumor cell line and antibacterial activity against Enterobacter aerogenes and Escherichia coli with IC50 and MIC values of 8.3, 44.0 and 44.0 μmol/L, respectively.
A new cytotoxic pyrrolidinoindoline diketopiperazine dimer, cristatumin E (1), was isolated from the fermentation broth of the algal fungus Eurotium herbariorum HT-2 associated with the marine algae, Enteromorpha prolifera. The structure was determined by spectroscopic analyses and Marfey's amino acid analysis. Cristatumin E (1) showed cytotoxicity against K562 tumor cell line and antibacterial activity against Enterobacter aerogenes and Escherichia coli with IC50 and MIC values of 8.3, 44.0 and 44.0 μmol/L, respectively.
2013, 24(12): 1053-1058
Abstract:
A simple spectrophotometric assay of H2O2 and glucose using Ag nanoparticles has been carried out. Relying on the synergistic effect of H2O2 reduction and ultraviolet (UV) irradiation, Ag nanoparticles with enhanced absorption signals were synthesized. H2O2 served as a reducing agent in the Ag nanoparticles formation in which Ag+ was reduced to Ag0 by O2- generated via the decomposition of H2O2 in alkaline media. On the other hand, photoreduction of Ag+ to Ag0 under UV irradiations also contributed to the nanoparticles formation. The synthesized nanoparticles were characterized by TEM, XPS, and XRD. The proposed method could determine H2O2 with concentrations ranging from 5.0×10-7 to 6.0×10-5 mol/ L. The detection limit was estimated to be 2.0×10-7 mol/L. Since the conversion of glucose to gluconic acid catalyzed by glucose oxidase was companied with the formation of H2O2, the sensing protocol has been successfully utilized for the determination of glucose in human blood samples. The results were in good agreement with those determined by a local hospital. This colorimetric sensor thus holds great promises in clinical applications.
A simple spectrophotometric assay of H2O2 and glucose using Ag nanoparticles has been carried out. Relying on the synergistic effect of H2O2 reduction and ultraviolet (UV) irradiation, Ag nanoparticles with enhanced absorption signals were synthesized. H2O2 served as a reducing agent in the Ag nanoparticles formation in which Ag+ was reduced to Ag0 by O2- generated via the decomposition of H2O2 in alkaline media. On the other hand, photoreduction of Ag+ to Ag0 under UV irradiations also contributed to the nanoparticles formation. The synthesized nanoparticles were characterized by TEM, XPS, and XRD. The proposed method could determine H2O2 with concentrations ranging from 5.0×10-7 to 6.0×10-5 mol/ L. The detection limit was estimated to be 2.0×10-7 mol/L. Since the conversion of glucose to gluconic acid catalyzed by glucose oxidase was companied with the formation of H2O2, the sensing protocol has been successfully utilized for the determination of glucose in human blood samples. The results were in good agreement with those determined by a local hospital. This colorimetric sensor thus holds great promises in clinical applications.
2013, 24(12): 1059-1063
Abstract:
Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from sixmembered cyclic nitrones through a concise two-step procedure, i.e., Grignard reagent addition and deprotection. These novel polyhydroxylated piperidine iminosugars were assayed against 10 types of enzymes. Only compound 8 exhibited weak inhibition (IC50 1080 μmol/L) against β-galactosidase from rat intestinal lactases.
Three pairs of novel 2-aryl-3,4,5-trihydroxypiperidines (6-8 and their enantiomers), the piperidine analogues of the pyrrolidine alkaloids radicamine A and radicamine B, were prepared from sixmembered cyclic nitrones through a concise two-step procedure, i.e., Grignard reagent addition and deprotection. These novel polyhydroxylated piperidine iminosugars were assayed against 10 types of enzymes. Only compound 8 exhibited weak inhibition (IC50 1080 μmol/L) against β-galactosidase from rat intestinal lactases.
2013, 24(12): 1064-1066
Abstract:
Nine 5-aryl-2-methyloxazole derivatives were synthesized via gold-catalyzed alkyne oxidation. All of the compounds have been screened for their antiproliferative activities against MCF-7 cell (human breast carcinoma), A549 cell (human lung carcinoma) and Hela cell (human cervical carcinoma) lines in vitro. The results revealed that compounds 1b,1c and 1d exhibited strong inhibitory activities against the MCF-7 cell lines (with IC50 values of 4.6, 9.7 and 2.2 μmol/L, respectively).
Nine 5-aryl-2-methyloxazole derivatives were synthesized via gold-catalyzed alkyne oxidation. All of the compounds have been screened for their antiproliferative activities against MCF-7 cell (human breast carcinoma), A549 cell (human lung carcinoma) and Hela cell (human cervical carcinoma) lines in vitro. The results revealed that compounds 1b,1c and 1d exhibited strong inhibitory activities against the MCF-7 cell lines (with IC50 values of 4.6, 9.7 and 2.2 μmol/L, respectively).
2013, 24(12): 1067-1069
Abstract:
Fast analysis of thiocyanate by ion-pair chromatography using a silica-based monolithic column and direct conductivity detection was carried out. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e using tetrabutylammonium hydroxide (TBA)-phthalic acid-acetonitrile as eluent. The effects of eluent concentration, eluent pH value, column temperature and flow rate on retention time of thiocyanate were investigated. The optimized chromatographic conditions for the determination of thiocyanate were as follows: 0.25 mmol/L TBA-0.18 mmol/L phthalate-7% acetonitrile (pH 5.5) as eluent, column temperature of 30℃, and flow rate of 6.0 mL/min. Retention time of thiocyanate was less than 1 min under the conditions. Common anions (Cl-, NO3-, SO42- and I-) did not interfere with the determination of thiocyanate. Detection limit (S/N = 3) of thiocyanate was 0.96 mg/L. Calibration graph between peak area and the concentration of thiocyanate was linear in the range of 2.0- 100.0 mg/L. Relative standard deviation (RSD) of chromatographic peak area was 1.4% (n = 5). This method has been applied to the determination of thiocyanate in ionic liquids. Recoveries of thiocyanate after spiking were 100.5%.
Fast analysis of thiocyanate by ion-pair chromatography using a silica-based monolithic column and direct conductivity detection was carried out. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e using tetrabutylammonium hydroxide (TBA)-phthalic acid-acetonitrile as eluent. The effects of eluent concentration, eluent pH value, column temperature and flow rate on retention time of thiocyanate were investigated. The optimized chromatographic conditions for the determination of thiocyanate were as follows: 0.25 mmol/L TBA-0.18 mmol/L phthalate-7% acetonitrile (pH 5.5) as eluent, column temperature of 30℃, and flow rate of 6.0 mL/min. Retention time of thiocyanate was less than 1 min under the conditions. Common anions (Cl-, NO3-, SO42- and I-) did not interfere with the determination of thiocyanate. Detection limit (S/N = 3) of thiocyanate was 0.96 mg/L. Calibration graph between peak area and the concentration of thiocyanate was linear in the range of 2.0- 100.0 mg/L. Relative standard deviation (RSD) of chromatographic peak area was 1.4% (n = 5). This method has been applied to the determination of thiocyanate in ionic liquids. Recoveries of thiocyanate after spiking were 100.5%.
2013, 24(12): 1070-1074
Abstract:
The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7(1H,3H)-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.
The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7(1H,3H)-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.
2013, 24(12): 1075-1079
Abstract:
In this paper, with K+, Ca2+ and Fe3+ as the objects of study, retardation of soil-bentonite (SB) barrier materials for metal ions with different valences is investigated, and the adsorption mechanism, migration patterns and permeation behavior are explored so as to provide a theoretical basis for their application. The results show that the adsorption process for metal ions with different valences by SB barriermaterials is fast, and the higher the valence, the greater the adsorption capacity. The fitting of the adsorption process conforms to pseudo-second-order adsorption kinetics and Langmuir-Freundlich adsorption equation, which explains that chemical adsorption is the dominating state and that the SB surface has certain heterogeneity. The permeability coefficient of K+, Ca2+ and Fe3+ in SB each has a maximum and the higher the valence, the sooner the maximum appears. Also the higher the valence, the more obvious the effect on SB retardation performance; and the sooner the ion breaks through the barrier wall completely, that is, the wall's retardation performance for higher valent ions may decline. 2013 Shu-Qing Lv. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
In this paper, with K+, Ca2+ and Fe3+ as the objects of study, retardation of soil-bentonite (SB) barrier materials for metal ions with different valences is investigated, and the adsorption mechanism, migration patterns and permeation behavior are explored so as to provide a theoretical basis for their application. The results show that the adsorption process for metal ions with different valences by SB barriermaterials is fast, and the higher the valence, the greater the adsorption capacity. The fitting of the adsorption process conforms to pseudo-second-order adsorption kinetics and Langmuir-Freundlich adsorption equation, which explains that chemical adsorption is the dominating state and that the SB surface has certain heterogeneity. The permeability coefficient of K+, Ca2+ and Fe3+ in SB each has a maximum and the higher the valence, the sooner the maximum appears. Also the higher the valence, the more obvious the effect on SB retardation performance; and the sooner the ion breaks through the barrier wall completely, that is, the wall's retardation performance for higher valent ions may decline. 2013 Shu-Qing Lv. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
2013, 24(12): 1080-1082
Abstract:
A continuing phytochemical study on the semi-mangrove plant Hibiscus tiliaceus yielded two new tetracyclic triterpenoids (3β,24S)-19(10→9)-abeo-8α,9β,10α-eupha-5,25(26)-dien-3,24-diol (tiliacol A, 1), and (3β,23Z)-19(10→9)-abeo-8α,9β,10α-tircalla-5,23-dien-3,25-diol (tiliacol B, 3), together with one known analog (2). Their structures were elucidated on the basis of extensive spectral analyses (MS, IR, 1D NMR and 2D NMR) and comparison with literature compounds. Compound 12 showed potent cytotoxicity against both P388 and HeLa cells with IC50 values of 11.2 μmol/L and 11.5 μmol/L, respectively.
A continuing phytochemical study on the semi-mangrove plant Hibiscus tiliaceus yielded two new tetracyclic triterpenoids (3β,24S)-19(10→9)-abeo-8α,9β,10α-eupha-5,25(26)-dien-3,24-diol (tiliacol A, 1), and (3β,23Z)-19(10→9)-abeo-8α,9β,10α-tircalla-5,23-dien-3,25-diol (tiliacol B, 3), together with one known analog (2). Their structures were elucidated on the basis of extensive spectral analyses (MS, IR, 1D NMR and 2D NMR) and comparison with literature compounds. Compound 12 showed potent cytotoxicity against both P388 and HeLa cells with IC50 values of 11.2 μmol/L and 11.5 μmol/L, respectively.
2013, 24(12): 1083-1086
Abstract:
This paper studied the mechanism of the alkene insertion elementary step in the asymmetric hydroformylation (AHF) catalyzed by RhH(CO)2[(R,S)-Yanphos] using four alkene substrates (CH2=CH- Ph, CH2=CH-Ph-(p)-Me, CH2=CH-C(=O)OCH3 and CH2=CH-OC(=O)-Ph, abbreviated as A1-A4). Interestingly, the equatorial vertical coordination mode (A mode) with respect to the Rh center was found for A1 and A2 but not for A3 and A4, although the equatorial in-plane coordinationmode (Emode) was found for A1-A4. The relative energy of the Emode of the η2-intermediates is lower than that of the A mode. In the alkene insertion step, Path 1 is more favorable than Path 2 for this system. As for A1 and A2, there could be a transformation between 2eq and 2ax.
This paper studied the mechanism of the alkene insertion elementary step in the asymmetric hydroformylation (AHF) catalyzed by RhH(CO)2[(R,S)-Yanphos] using four alkene substrates (CH2=CH- Ph, CH2=CH-Ph-(p)-Me, CH2=CH-C(=O)OCH3 and CH2=CH-OC(=O)-Ph, abbreviated as A1-A4). Interestingly, the equatorial vertical coordination mode (A mode) with respect to the Rh center was found for A1 and A2 but not for A3 and A4, although the equatorial in-plane coordinationmode (Emode) was found for A1-A4. The relative energy of the Emode of the η2-intermediates is lower than that of the A mode. In the alkene insertion step, Path 1 is more favorable than Path 2 for this system. As for A1 and A2, there could be a transformation between 2eq and 2ax.
2013, 24(12): 1087-1090
Abstract:
In this paper, a novel biosensor was prepared by immobilizing glucose oxidase (GOx) on carbon nanotube-gold-titania nanocomposites (CNT/Au/TiO2) modified glassy carbon electrode (GCE). SEM was initially used to investigate the surface morphology of CNT/Au/TiO2 nanocomposites modified GCE, indicating the formation of the nano-porous structure which could readily facilitate the attachment of GOx on the electrode surface. Cyclic voltammogram (CV) and electrochemical impedance spectrum (EIS) were further utilized to explore relevant electrochemical activity on CNT/Au/TiO2 nanocomposites modified GCE. The observations demonstrated that the immobilized GOx could efficiently execute its bioelectrocatalytic activity for the oxidation of glucose. The biosensor exhibited a wider linearity range from 0.1 mmol L-1 to 8 mmol L-1 glucose with a detection limit of 0.077 mmol L-1.
In this paper, a novel biosensor was prepared by immobilizing glucose oxidase (GOx) on carbon nanotube-gold-titania nanocomposites (CNT/Au/TiO2) modified glassy carbon electrode (GCE). SEM was initially used to investigate the surface morphology of CNT/Au/TiO2 nanocomposites modified GCE, indicating the formation of the nano-porous structure which could readily facilitate the attachment of GOx on the electrode surface. Cyclic voltammogram (CV) and electrochemical impedance spectrum (EIS) were further utilized to explore relevant electrochemical activity on CNT/Au/TiO2 nanocomposites modified GCE. The observations demonstrated that the immobilized GOx could efficiently execute its bioelectrocatalytic activity for the oxidation of glucose. The biosensor exhibited a wider linearity range from 0.1 mmol L-1 to 8 mmol L-1 glucose with a detection limit of 0.077 mmol L-1.
2013, 24(12): 1091-1094
Abstract:
A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps: (a) the synthesis of 3-methoxy-4- benzyloxyacetophenone (2) from acetovanillone (1), (b) the bromination of compound 2 to produce 3- methoxy-4-benzyloxy-α-bromoacetophenone (3), and (c) followed by a nucleophilic substitution of compound (3) to obtain 3-methoxy-4-benzyloxy-α-(3-methoxy-4-(1-propenyl)phenol)-acetophenone (4). The target product was characterized by MS, 1H NMR and 13C NMR spectroscopy. It was found that the trimeric compound synthesized can be used as a preferable lignin model compound because it contains guaiacyl structural unit (3-methoxy-4-hydroxy phenyl propane) linked by α-O-4 and β-O-4 linkages. In addition, under the conditions of microwave irradiation, the reaction time of each step is significantly reduced, and the selectivity of target product is greatly improved. The yields of each step and the overall sequence are 95.31%, 87.3%, 90.6% and 75.4% (95.31%×87.3%×90.6%), respectively.
A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps: (a) the synthesis of 3-methoxy-4- benzyloxyacetophenone (2) from acetovanillone (1), (b) the bromination of compound 2 to produce 3- methoxy-4-benzyloxy-α-bromoacetophenone (3), and (c) followed by a nucleophilic substitution of compound (3) to obtain 3-methoxy-4-benzyloxy-α-(3-methoxy-4-(1-propenyl)phenol)-acetophenone (4). The target product was characterized by MS, 1H NMR and 13C NMR spectroscopy. It was found that the trimeric compound synthesized can be used as a preferable lignin model compound because it contains guaiacyl structural unit (3-methoxy-4-hydroxy phenyl propane) linked by α-O-4 and β-O-4 linkages. In addition, under the conditions of microwave irradiation, the reaction time of each step is significantly reduced, and the selectivity of target product is greatly improved. The yields of each step and the overall sequence are 95.31%, 87.3%, 90.6% and 75.4% (95.31%×87.3%×90.6%), respectively.
2013, 24(12): 1095-1098
Abstract:
A reaction between 1,3-dioxo-N-aryl-2,3-dihydro-1H-indene-2-carboxamides, dialkyl acetylenedicarboxylates, and triphenylphosphine or trimethylphosphite is described as a simple and efficient method for the synthesis of 5-hydroxy-4-aryl-2,5-dihydrofuran-2,3-dicarboxylate derivatives.
A reaction between 1,3-dioxo-N-aryl-2,3-dihydro-1H-indene-2-carboxamides, dialkyl acetylenedicarboxylates, and triphenylphosphine or trimethylphosphite is described as a simple and efficient method for the synthesis of 5-hydroxy-4-aryl-2,5-dihydrofuran-2,3-dicarboxylate derivatives.
2013, 24(12): 1099-1102
Abstract:
In a novel procedure, human serum albumin functionalized magnetic nanoparticles (HSA-MNPs) were used to selectively extract nine flavonoids in the extract of Ginkgo biloba leaves. The chemical structures of those flavonoids were characterized with high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The selective extraction with HSA-MNPs coupled with structural elucidation with HPLC-MS shows powerful potential for analysis of bioactive components in traditional Chinese medicines.
In a novel procedure, human serum albumin functionalized magnetic nanoparticles (HSA-MNPs) were used to selectively extract nine flavonoids in the extract of Ginkgo biloba leaves. The chemical structures of those flavonoids were characterized with high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The selective extraction with HSA-MNPs coupled with structural elucidation with HPLC-MS shows powerful potential for analysis of bioactive components in traditional Chinese medicines.
2013, 24(12): 1103-1105
Abstract:
In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can be obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperature, using DMSO as a solvent. The reaction mechanism was discussed. The method provides a new and expedient path for the preparation of S-aryl phosphorothioates.
In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can be obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperature, using DMSO as a solvent. The reaction mechanism was discussed. The method provides a new and expedient path for the preparation of S-aryl phosphorothioates.
2013, 24(12): 1106-1108
Abstract:
A novel diether-ester conjugated electron donor model compound, 1,3-dimethoxypropan-2-yl benzoate, was synthesized via a reaction of 1,3-dimethoxypropan-2-ol and benzoyl chloride in the presence of triethyl amine and 4-dimethylaminopryidine. Compared to the known routes of preparing diethers, which usually employ the reactions to O-alkylate the corresponding diols with O-alkylating reagents, the presented method here provides a new way to prepare the diether electron donor compounds. It avoids employing the traditional O-alkylation reactions, so that highly toxic O-alkylating chemicals, such as iodomethane, and very strong basic deprotonating reagents, such as alkoxides or metal hydrides, are not required. The product can be obtained in high yields without complicated purification processes. Catalyst component containing the electron donor compound was prepared and used to catalyze propylene polymerization.
A novel diether-ester conjugated electron donor model compound, 1,3-dimethoxypropan-2-yl benzoate, was synthesized via a reaction of 1,3-dimethoxypropan-2-ol and benzoyl chloride in the presence of triethyl amine and 4-dimethylaminopryidine. Compared to the known routes of preparing diethers, which usually employ the reactions to O-alkylate the corresponding diols with O-alkylating reagents, the presented method here provides a new way to prepare the diether electron donor compounds. It avoids employing the traditional O-alkylation reactions, so that highly toxic O-alkylating chemicals, such as iodomethane, and very strong basic deprotonating reagents, such as alkoxides or metal hydrides, are not required. The product can be obtained in high yields without complicated purification processes. Catalyst component containing the electron donor compound was prepared and used to catalyze propylene polymerization.
2013, 24(12): 1109-1111
Abstract:
A non-precious metal catalyst CoMe/C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black,melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The catalytic activity of CoMe/C is characterized by the electrochemical linear sweep voltammetry technique. The onset reduction potential of the catalyst is 0.55 V (vs. SCE) at a scanning rate of 5 mV/s in 0.5 mol/L H2SO4 solution. The formation of the ORR activity sites of CoMe/C is facilitated by metallic β-cobalt.
A non-precious metal catalyst CoMe/C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black,melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The catalytic activity of CoMe/C is characterized by the electrochemical linear sweep voltammetry technique. The onset reduction potential of the catalyst is 0.55 V (vs. SCE) at a scanning rate of 5 mV/s in 0.5 mol/L H2SO4 solution. The formation of the ORR activity sites of CoMe/C is facilitated by metallic β-cobalt.
2013, 24(12): 1112-1114
Abstract:
We report an efficient kinetic resolution of racemic 2-(4-chlorophenyl)-4-hydroxytetrahydro-pyran (CLP-4-HTHP) via Pseudomonas cepacia lipase (PSL)-catalyzed transesterification, where PSL is immobilized on a core-shell MnFe2O4@SiO2-(CH2)3-NH2 carrier and used as a magnetically separable catalyst. The as-synthesized PSL/MnFe2O4@SiO2-(CH2)3-NH2 catalyst exhibits enhanced catalytic activity for resolving racemic CLP-4-HTHP to the corresponding optically pure (2R,4S)-CLP-4-HTHP compared to the free PSL. The ees for the former is 2.3 times larger than that for the latter under optimized conditions (99.4% and 44.1%, respectively), although the eep for them are same (99.2%). Meanwhile, the PSL/MnFe2O4@SiO2-(CH2)3-NH2 catalyst possesses a high saturate magnetization of 59.7 emu/g and could be easily recovered bymagnetic separation and reused. The catalytic activity in six recycling tests did not significantly decrease, suggesting its great potential for industrial applications.
We report an efficient kinetic resolution of racemic 2-(4-chlorophenyl)-4-hydroxytetrahydro-pyran (CLP-4-HTHP) via Pseudomonas cepacia lipase (PSL)-catalyzed transesterification, where PSL is immobilized on a core-shell MnFe2O4@SiO2-(CH2)3-NH2 carrier and used as a magnetically separable catalyst. The as-synthesized PSL/MnFe2O4@SiO2-(CH2)3-NH2 catalyst exhibits enhanced catalytic activity for resolving racemic CLP-4-HTHP to the corresponding optically pure (2R,4S)-CLP-4-HTHP compared to the free PSL. The ees for the former is 2.3 times larger than that for the latter under optimized conditions (99.4% and 44.1%, respectively), although the eep for them are same (99.2%). Meanwhile, the PSL/MnFe2O4@SiO2-(CH2)3-NH2 catalyst possesses a high saturate magnetization of 59.7 emu/g and could be easily recovered bymagnetic separation and reused. The catalytic activity in six recycling tests did not significantly decrease, suggesting its great potential for industrial applications.
2013, 24(12): 1115-1117
Abstract:
A new one-step synthesis of 3-hydroxymethylbenzofuran, based on intramolecular cyclization of 2- (methoxymethyl)-2-(2'-methoxymethyl-4'-methylphenyl)-butanone 1 under diluted hydrochloric acid in THF, was developed. The mechanism for this process was investigated via chemical equilibrium shift of tautomer in acidic conditions. The applicability of this new method was studied further in this paper.
A new one-step synthesis of 3-hydroxymethylbenzofuran, based on intramolecular cyclization of 2- (methoxymethyl)-2-(2'-methoxymethyl-4'-methylphenyl)-butanone 1 under diluted hydrochloric acid in THF, was developed. The mechanism for this process was investigated via chemical equilibrium shift of tautomer in acidic conditions. The applicability of this new method was studied further in this paper.
2013, 24(12): 1118-1122
Abstract:
The synthesis of two isomers of Aprepitant (APT) and three isomers of Fosaprepitant (FPT), crucial components for quality control in manufacturing, is described. Herein, three chiral centers in the isomers of Aprepitant are established in high yield by induced crystallization and chiral reduction. Additionally, the isomers of Aprepitant are utilized to synthesize the isomers of Fosaprepitant with the same stereochemistry. All the target compounds were confirmed by elemental analyses, IR, NMR and MS data analysis.
The synthesis of two isomers of Aprepitant (APT) and three isomers of Fosaprepitant (FPT), crucial components for quality control in manufacturing, is described. Herein, three chiral centers in the isomers of Aprepitant are established in high yield by induced crystallization and chiral reduction. Additionally, the isomers of Aprepitant are utilized to synthesize the isomers of Fosaprepitant with the same stereochemistry. All the target compounds were confirmed by elemental analyses, IR, NMR and MS data analysis.
2013, 24(12): 1123-1126
Abstract:
N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide (TBBDA)/triphenylphosphine and N,N,N',N'-tetrachlorobenzene- 1,3-disulfonamide (TCBDA)/triphenylphosphine have been introduced as highly efficient systems for the versatile conversion of aldoxime derivatives into nitriles. The process reported here is operationally simple and reactions have been mildly performed in dichloromethane at room temperature.
N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide (TBBDA)/triphenylphosphine and N,N,N',N'-tetrachlorobenzene- 1,3-disulfonamide (TCBDA)/triphenylphosphine have been introduced as highly efficient systems for the versatile conversion of aldoxime derivatives into nitriles. The process reported here is operationally simple and reactions have been mildly performed in dichloromethane at room temperature.
2013, 24(12): 1127-1129
Abstract:
The vapor-phase synthesis of 3-methylindole from glycerol and aniline over Cu/NaY modified by K2O was investigated. The catalysts were characterized by X-ray diffraction (XRD) and the temperatureprogrammed desorption of ammonia (NH3-TPD). The effect of the reaction temperature on the activity and selectivity of Cu/NaY-K2O catalyst was also investigated. The results indicated that the addition of K2O to Cu/NaY increased the selectivity of the catalyst remarkably because the amount of middle-strong acid sites decreased clearly. The decrease of the reaction temperature was beneficial for the increase of 3- methylindole selectivity. Over Cu/NaY-K2O, the selectivity of 3-methylindole reached 75% and the yield of the target product was up to 47% at 220℃. A probable catalytic mechanism for the synthesis of 3- methylindole from glycerol and aniline was proposed.
The vapor-phase synthesis of 3-methylindole from glycerol and aniline over Cu/NaY modified by K2O was investigated. The catalysts were characterized by X-ray diffraction (XRD) and the temperatureprogrammed desorption of ammonia (NH3-TPD). The effect of the reaction temperature on the activity and selectivity of Cu/NaY-K2O catalyst was also investigated. The results indicated that the addition of K2O to Cu/NaY increased the selectivity of the catalyst remarkably because the amount of middle-strong acid sites decreased clearly. The decrease of the reaction temperature was beneficial for the increase of 3- methylindole selectivity. Over Cu/NaY-K2O, the selectivity of 3-methylindole reached 75% and the yield of the target product was up to 47% at 220℃. A probable catalytic mechanism for the synthesis of 3- methylindole from glycerol and aniline was proposed.
2013, 24(12): 1130-1133
Abstract:
The reaction of furan-2,3-diones with S-methylisothiosemicarbazide hydroiodide yielded novel 1,2,4- triazine-5(4H)-ones, and reaction of furan-2,3-diones with diaminomaleonitrile led to the formation of pyrazine-2,3-dicarbonitrile derivatives, and the hydrolysis of these products led to the formation of more new pyrazine-2,3-dicarbonitrile derivatives. These compounds are potential herbicides and pesticides.
The reaction of furan-2,3-diones with S-methylisothiosemicarbazide hydroiodide yielded novel 1,2,4- triazine-5(4H)-ones, and reaction of furan-2,3-diones with diaminomaleonitrile led to the formation of pyrazine-2,3-dicarbonitrile derivatives, and the hydrolysis of these products led to the formation of more new pyrazine-2,3-dicarbonitrile derivatives. These compounds are potential herbicides and pesticides.
Synthesis and biological evaluation of novel 1,2,4-triazole containing 1,2,3-thiadiazole derivatives
2013, 24(12): 1134-1136
Abstract:
A series of novel 1,2,4-triazoles containing 1,2,3-thiadiazole derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1H NMR, and elemental analysis and ESI-MS or HRMS. Preliminary bioassays indicated that these compounds exhibited very good insecticidal activity against Aphis laburni at 100 mg/mL, with mortality no less than 95%. Compounds 6a, 6c, 6f, 6l showed higher curative activity against TMV and compound 6h showed a higher induction effects against TMV in vivo at 100 μg/mL. Collectively, our data demonstrate a new strategy for control of insects and viruses.
A series of novel 1,2,4-triazoles containing 1,2,3-thiadiazole derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1H NMR, and elemental analysis and ESI-MS or HRMS. Preliminary bioassays indicated that these compounds exhibited very good insecticidal activity against Aphis laburni at 100 mg/mL, with mortality no less than 95%. Compounds 6a, 6c, 6f, 6l showed higher curative activity against TMV and compound 6h showed a higher induction effects against TMV in vivo at 100 μg/mL. Collectively, our data demonstrate a new strategy for control of insects and viruses.
2013, 24(12): 1137-1139
Abstract:
Two sulphonate-crown ether surfactants (sodium (4'-dodecanoyldibenzo-18-crown-6)-4"(5")-sulphonate, ammonium (4'-dodecanoyldibenzo-18-crown-6)-4"(5")-sulphonate) were designed and synthesized via a two-step continuous method. The products were purified and characterized by IR, 1H NMR and elemental analysis. The physicochemical properties of the surfactants were studied by fluorescence, conductivity and dynamic light scattering techniques.
Two sulphonate-crown ether surfactants (sodium (4'-dodecanoyldibenzo-18-crown-6)-4"(5")-sulphonate, ammonium (4'-dodecanoyldibenzo-18-crown-6)-4"(5")-sulphonate) were designed and synthesized via a two-step continuous method. The products were purified and characterized by IR, 1H NMR and elemental analysis. The physicochemical properties of the surfactants were studied by fluorescence, conductivity and dynamic light scattering techniques.
2013, 24(12): 1140-1144
Abstract:
The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles (TCRPs) were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia (edition 2010) was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples of Flos Carthami can produce remarkably similar TCRPs. The quality of Flos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aimof our study is to establish a new standard for quality evaluation.
The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles (TCRPs) were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia (edition 2010) was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples of Flos Carthami can produce remarkably similar TCRPs. The quality of Flos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aimof our study is to establish a new standard for quality evaluation.
2013, 24(12): 1145-1147
Abstract:
The spectra of four tanshinones in the potentiostatic reduction process, including tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone, were investigated using spectroelectrochemical cell and UV spectrophotometer. Their cyclic voltammograms (CVs) were recorded with a glassy carbon electrode (GCE). The experiment results show that the antioxidant activity of these tanshinones, in the structure, where A, B and C rings connect through a single double bond, is weaker than that where A ring does not have double bond. Moreover, the increasing angle strain in the reduction process could enhance the antioxidant activity. In summary, the rank of antioxidant activities of these tanshinones, from weak to strong, is tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone.
The spectra of four tanshinones in the potentiostatic reduction process, including tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone, were investigated using spectroelectrochemical cell and UV spectrophotometer. Their cyclic voltammograms (CVs) were recorded with a glassy carbon electrode (GCE). The experiment results show that the antioxidant activity of these tanshinones, in the structure, where A, B and C rings connect through a single double bond, is weaker than that where A ring does not have double bond. Moreover, the increasing angle strain in the reduction process could enhance the antioxidant activity. In summary, the rank of antioxidant activities of these tanshinones, from weak to strong, is tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone.
