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2011 Volume 22 Issue 3
2011, 22(3): 253-255
doi: 10.1016/j.cclet.2010.10.005
Abstract:
Several 6-aminoquinoline derivatives, which could be used in drug design, have been synthesized. The reaction conditions were comparatively studied, and the p-chloroaniline was used as optimum oxidant in Skraup-Doebner-Von Miller reaction. The nitro group was reduced effectively by SnCl2 with no halo-removed occurred.
Several 6-aminoquinoline derivatives, which could be used in drug design, have been synthesized. The reaction conditions were comparatively studied, and the p-chloroaniline was used as optimum oxidant in Skraup-Doebner-Von Miller reaction. The nitro group was reduced effectively by SnCl2 with no halo-removed occurred.
2011, 22(3): 256-259
doi: 10.1016/j.cclet.2010.10.029
Abstract:
The estrogen receptor is a target for therapeutic agents for hormone replacement in menopausal women, osteoporosis, reproductive cancers such as breast cancer, uterine cancer and prostate cancer. 1,4-Dihydrothieno [3',2':5,6] thiopyrano [4,3-c] pyrazole-3-carboxylic amide derivatives were designed, synthesized and biological evaluated as potential estrogen receptor antagonists.
The estrogen receptor is a target for therapeutic agents for hormone replacement in menopausal women, osteoporosis, reproductive cancers such as breast cancer, uterine cancer and prostate cancer. 1,4-Dihydrothieno [3',2':5,6] thiopyrano [4,3-c] pyrazole-3-carboxylic amide derivatives were designed, synthesized and biological evaluated as potential estrogen receptor antagonists.
2011, 22(3): 260-263
doi: 10.1016/j.cclet.2010.09.017
Abstract:
A series of azomethine esters, 3-hydroxy-4-{[(4-iodophenyl)imino]methyl}phenyl alkanoates possessing even number of carbon atoms at the terminal alkanoyloxy chain (Cn-1H2n-1COO-, n=4,6,8,10,12,14) was synthesized. n-Butanoyloxy was found non-mesogenic, whilst n-hexanoyloxy to n-tetradecanoyloxy exhibited enantiotropic smectic A phase with fan-shaped texture. It was found that the length of terminal alkanoyloxy chain influenced the mesomorphic properties.
A series of azomethine esters, 3-hydroxy-4-{[(4-iodophenyl)imino]methyl}phenyl alkanoates possessing even number of carbon atoms at the terminal alkanoyloxy chain (Cn-1H2n-1COO-, n=4,6,8,10,12,14) was synthesized. n-Butanoyloxy was found non-mesogenic, whilst n-hexanoyloxy to n-tetradecanoyloxy exhibited enantiotropic smectic A phase with fan-shaped texture. It was found that the length of terminal alkanoyloxy chain influenced the mesomorphic properties.
2011, 22(3): 264-267
doi: 10.1016/j.cclet.2010.10.021
Abstract:
Asymmetric conjugated addition of allylcopper reagents derived from an allyl Grignard reagent and CuBr·Me2S to chiral α,β-unsaturated N-acyl oxazolidinones has been achieved. The synthetic procedure was applied to the preparation of the key intermediate of the novel nonbenzodiazepine hypnotic drug, ramelteon.
Asymmetric conjugated addition of allylcopper reagents derived from an allyl Grignard reagent and CuBr·Me2S to chiral α,β-unsaturated N-acyl oxazolidinones has been achieved. The synthetic procedure was applied to the preparation of the key intermediate of the novel nonbenzodiazepine hypnotic drug, ramelteon.
2011, 22(3): 268-271
doi: 10.1016/j.cclet.2010.09.032
Abstract:
A CrO3 catalyzed oxidation of homopropargyl alcohols with tert-butyl hydroperoxide under microwave irradiation was found to be an efficient and rapid alternative for the preparation of 1,2-allenic ketones. The advantages of this procedure include short reaction time, less adverse impact on the environment and reasonably high efficiency.
A CrO3 catalyzed oxidation of homopropargyl alcohols with tert-butyl hydroperoxide under microwave irradiation was found to be an efficient and rapid alternative for the preparation of 1,2-allenic ketones. The advantages of this procedure include short reaction time, less adverse impact on the environment and reasonably high efficiency.
2011, 22(3): 272-275
doi: 10.1016/j.cclet.2010.09.033
Abstract:
A series of 7-azaindol derivatives were designed based on the homologous 3D model of human acrosin. These compounds were synthesized and evaluated for their human acrosin inhibitory activities in vitro. Compounds 7a, 7i, 7j, 7k and 7n showed highly inhibitory activity against human acrosin. The three-dimensional structure-activity relationship was investigated through a CoMFA model, which provided valuable information to further study of potential human acrosin inhibitors.
A series of 7-azaindol derivatives were designed based on the homologous 3D model of human acrosin. These compounds were synthesized and evaluated for their human acrosin inhibitory activities in vitro. Compounds 7a, 7i, 7j, 7k and 7n showed highly inhibitory activity against human acrosin. The three-dimensional structure-activity relationship was investigated through a CoMFA model, which provided valuable information to further study of potential human acrosin inhibitors.
2011, 22(3): 276-279
doi: 10.1016/j.cclet.2010.09.034
Abstract:
An efficient and clean synthesis of N-arylpyrrolidines from arylamines and 1,4-dimesyloxybutane was developed using microwave irradiation in an aqueous potassium carbonate medium without any catalyst. The procedure is rapid, simple and convenient.
An efficient and clean synthesis of N-arylpyrrolidines from arylamines and 1,4-dimesyloxybutane was developed using microwave irradiation in an aqueous potassium carbonate medium without any catalyst. The procedure is rapid, simple and convenient.
2011, 22(3): 280-283
doi: 10.1016/j.cclet.2010.10.016
Abstract:
Ethylene trithiocarbonate reacted with dimethyl acetylenedicarboxylate to furnish tetramethyl thiopyran-4-spiro-2'-(l,3-dithiolane)-2,3,5,6-tetracarboxylate, a new thiopyran-4-spiro-2'-(l,3-dithiolane) heterocyclic compound, as the minor product together with the major product dimethyl 2-thioxo-l,3-dithiole-4,5-dicarboxylate. The new heterocycle was probably formed through a [2+2] cycloaddition between ethylene trithiocarbonate and dimethyl acetylenedicarboxylate followed by a 1,3-dipolar cycloaddition or [4+2] cycloaddition. Crystal structure of the new compound revealed that the thiopyran ring and 1,3-dithiolane moiety were perpendicular to each other.
Ethylene trithiocarbonate reacted with dimethyl acetylenedicarboxylate to furnish tetramethyl thiopyran-4-spiro-2'-(l,3-dithiolane)-2,3,5,6-tetracarboxylate, a new thiopyran-4-spiro-2'-(l,3-dithiolane) heterocyclic compound, as the minor product together with the major product dimethyl 2-thioxo-l,3-dithiole-4,5-dicarboxylate. The new heterocycle was probably formed through a [2+2] cycloaddition between ethylene trithiocarbonate and dimethyl acetylenedicarboxylate followed by a 1,3-dipolar cycloaddition or [4+2] cycloaddition. Crystal structure of the new compound revealed that the thiopyran ring and 1,3-dithiolane moiety were perpendicular to each other.
2011, 22(3): 284-287
doi: 10.1016/j.cclet.2010.10.004
Abstract:
A series of novel calix[4]arenecrown-6 derivatives with an alkenyl loop of various sizes 5-8 were synthesized via intramolecular ring closing olefin metathesis and characterized by 1H NMR, 13C NMR and ESI-HRMS. Their complexation property towards cesium ion was studied by 1H NMR technique. Two-phase extraction of alkali metal ions using UV-vis spectroscopy revealed remarkably different extractabilities. These results indicate that the complexation capacities towards cesium ions can be tuned and controlled through cooperative regulation of the strain of the loop and conformational change of calixcrown skelton.
A series of novel calix[4]arenecrown-6 derivatives with an alkenyl loop of various sizes 5-8 were synthesized via intramolecular ring closing olefin metathesis and characterized by 1H NMR, 13C NMR and ESI-HRMS. Their complexation property towards cesium ion was studied by 1H NMR technique. Two-phase extraction of alkali metal ions using UV-vis spectroscopy revealed remarkably different extractabilities. These results indicate that the complexation capacities towards cesium ions can be tuned and controlled through cooperative regulation of the strain of the loop and conformational change of calixcrown skelton.
2011, 22(3): 288-291
doi: 10.1016/j.cclet.2010.09.036
Abstract:
Various type of cesium partially substituted phosphotungstate, CsxH3-xPW12O40 (x=1.0, 2.0 and 2.5), were synthesized and their catalytic activities were investigated in the synthesis of quinoline. It was shown that catalytic activities of these catalysts correlated to surface acidity and total number of acidic sites. Finally, a series of quinoline derivatives were synthesized with Cs2.5H0.5PW12O40 via the Friedlander reaction in high to excellent yields and the plausible mechanism was proposed. Simple experiment, catalyst reusability, short reaction time and preclusion of toxic solvent are the advantages of this method.
Various type of cesium partially substituted phosphotungstate, CsxH3-xPW12O40 (x=1.0, 2.0 and 2.5), were synthesized and their catalytic activities were investigated in the synthesis of quinoline. It was shown that catalytic activities of these catalysts correlated to surface acidity and total number of acidic sites. Finally, a series of quinoline derivatives were synthesized with Cs2.5H0.5PW12O40 via the Friedlander reaction in high to excellent yields and the plausible mechanism was proposed. Simple experiment, catalyst reusability, short reaction time and preclusion of toxic solvent are the advantages of this method.
2011, 22(3): 292-295
doi: 10.1016/j.cclet.2010.09.037
Abstract:
The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields. This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligand.
The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields. This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligand.
2011, 22(3): 296-299
doi: 10.1016/j.cclet.2010.10.031
Abstract:
Vanadyl acetylacetonate, VO(acac)2, has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition. The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents. The benzimidazoles were obtained in quick time with high yields.
Vanadyl acetylacetonate, VO(acac)2, has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition. The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents. The benzimidazoles were obtained in quick time with high yields.
2011, 22(3): 300-302
doi: 10.1016/j.cclet.2010.10.009
Abstract:
In this letter, a mild and efficient procedure for synthesis of phenacyl derivatives under homogenous catalysis in the presence of tetrabutylammonium bromide in aqueous media is described. The nucleophilic substitution reactions were performed under ecofriendly conditions and gave the corresponding products in high yields and short reaction times.
In this letter, a mild and efficient procedure for synthesis of phenacyl derivatives under homogenous catalysis in the presence of tetrabutylammonium bromide in aqueous media is described. The nucleophilic substitution reactions were performed under ecofriendly conditions and gave the corresponding products in high yields and short reaction times.
2011, 22(3): 303-305
doi: 10.1016/j.cclet.2010.06.036
Abstract:
Hierarchical TS-1 has been synthesized in the presence of cationic organosilane surfactant. The material is characterized with XRD, TEM, N2 adsorption isotherm. The results show that the hierarchical TS-1 aggregates consist of small primary units with sizes of 20-30 nm. The BET surface area increases from 420 to 513 m2/g compared to conventional TS-1 zeolite. The sample is shown to be more active in epoxidation of cyclohexene than conventional TS-1.
Hierarchical TS-1 has been synthesized in the presence of cationic organosilane surfactant. The material is characterized with XRD, TEM, N2 adsorption isotherm. The results show that the hierarchical TS-1 aggregates consist of small primary units with sizes of 20-30 nm. The BET surface area increases from 420 to 513 m2/g compared to conventional TS-1 zeolite. The sample is shown to be more active in epoxidation of cyclohexene than conventional TS-1.
2011, 22(3): 306-309
doi: 10.1016/j.cclet.2010.10.018
Abstract:
An oxidative rearrangement of cyclic tertiary α-hydroxy allylsilanes has been carried out in refluxing ClCH2CH2Cl with pyridinium chlorochromate (PCC). The reaction provides a convenient method to synthesize cyclic β-silylenones in modest to excellent yields.
An oxidative rearrangement of cyclic tertiary α-hydroxy allylsilanes has been carried out in refluxing ClCH2CH2Cl with pyridinium chlorochromate (PCC). The reaction provides a convenient method to synthesize cyclic β-silylenones in modest to excellent yields.
2011, 22(3): 310-313
doi: 10.1016/j.cclet.2010.10.024
Abstract:
An efficient and mild protocol for bromination of aryl azides with N-bromosuccinimide (NBS) under FeCl3 catalysis in 1,2-dichloroethane was developed. It is proved to be an efficient method for obtaining brominated aryl azides.
An efficient and mild protocol for bromination of aryl azides with N-bromosuccinimide (NBS) under FeCl3 catalysis in 1,2-dichloroethane was developed. It is proved to be an efficient method for obtaining brominated aryl azides.
2011, 22(3): 314-317
doi: 10.1016/j.cclet.2010.10.032
Abstract:
An efficient 1-methylimidazole-catalyzed synthesis of dialkyl 2-[(4-methylphenyl)sulfonyl]-1H-pyrrole-3,4-dicarboxylates is described. The reactive 1:1 zwitterionic intermediate formed by the addition of 1-methylimidazole to dialkyl acetylenedicarboxylates is trapped by tosylmethyl isocyanide (TOSMIC) to afford the title compounds in excellent yields.
An efficient 1-methylimidazole-catalyzed synthesis of dialkyl 2-[(4-methylphenyl)sulfonyl]-1H-pyrrole-3,4-dicarboxylates is described. The reactive 1:1 zwitterionic intermediate formed by the addition of 1-methylimidazole to dialkyl acetylenedicarboxylates is trapped by tosylmethyl isocyanide (TOSMIC) to afford the title compounds in excellent yields.
2011, 22(3): 318-321
doi: 10.1016/j.cclet.2010.10.033
Abstract:
Melamine trisulfonic acid (MTSA) can be used as an efficient and recyclable catalyst for the promotion of the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs) in the absence of solvent. All reactions were performed at 80℃ in good to high yields.
Melamine trisulfonic acid (MTSA) can be used as an efficient and recyclable catalyst for the promotion of the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs) in the absence of solvent. All reactions were performed at 80℃ in good to high yields.
2011, 22(3): 322-325
doi: 10.1016/j.cclet.2010.10.046
Abstract:
Hafnium (IV) bis(perfluorooctanesulfonyl) imide complex is found to be an efficient catalyst for the multicomponent condensation of β-naphthol, aromatic aldehydes and urea or amides in perfluorodecalin to afford the corresponding substituted amidomethyl naphthols in good yields. The remarkable features of this new procedure are high yields, shorter reaction times, reusability of catalyst and simple work-up procedures.
Hafnium (IV) bis(perfluorooctanesulfonyl) imide complex is found to be an efficient catalyst for the multicomponent condensation of β-naphthol, aromatic aldehydes and urea or amides in perfluorodecalin to afford the corresponding substituted amidomethyl naphthols in good yields. The remarkable features of this new procedure are high yields, shorter reaction times, reusability of catalyst and simple work-up procedures.
2011, 22(3): 326-329
doi: 10.1016/j.cclet.2010.10.030
Abstract:
Two new phenethanol glycosides, named ligurobustoside P (1), Iigurobustoside Q (2) have been isolated from the leaves of Ligustrum robustum, together with the known compound angoroside A (3) which was firstly isolated from this species. The structures of the two new phenethanol glycosides (1-2) were elucidated by a combination of high-resolution electron ionization mass spectrometry (HR-ESI-MS), 1H NMR, 13C NMR, HMQC, and HMBC spectra for the first time.
Two new phenethanol glycosides, named ligurobustoside P (1), Iigurobustoside Q (2) have been isolated from the leaves of Ligustrum robustum, together with the known compound angoroside A (3) which was firstly isolated from this species. The structures of the two new phenethanol glycosides (1-2) were elucidated by a combination of high-resolution electron ionization mass spectrometry (HR-ESI-MS), 1H NMR, 13C NMR, HMQC, and HMBC spectra for the first time.
2011, 22(3): 330-333
doi: 10.1016/j.cclet.2010.10.044
Abstract:
A novel micelle to solvent stacking on-line sample preconcentration technique in capillary zone electrophoresis (MSS-CZE) has been developed to determine the strychnine and brucine in traditional Chinese medicine preparations. The optimal running buffer was 30 mmol/L H3PO4 containing 20% acetonitrile at pH 4.0. The sample matrix was 8 mmol/L H3PO4 containing 5 mmol/L sodium dodecyl sulfate (SDS) at pH 3.0. The established MSS-CZE method afforded more than 50-fold improvements in concentration sensitivity compared with typical CZE-UVanalysis. The calibration curve was linear in the range from 0.2 to 15.0 μg/mL for both strychnine and brucine, with correlation coefficients of 0.9984 and 0.9976, respectively. The limits of detection (S/N=3:1) for strychnine and brucine were 0.02 and 0.05 μg/mL, respectively. The MSS-CZE method has been successfully applied to the analysis of strychnine and brucine in Chinese medicinal preparations.
A novel micelle to solvent stacking on-line sample preconcentration technique in capillary zone electrophoresis (MSS-CZE) has been developed to determine the strychnine and brucine in traditional Chinese medicine preparations. The optimal running buffer was 30 mmol/L H3PO4 containing 20% acetonitrile at pH 4.0. The sample matrix was 8 mmol/L H3PO4 containing 5 mmol/L sodium dodecyl sulfate (SDS) at pH 3.0. The established MSS-CZE method afforded more than 50-fold improvements in concentration sensitivity compared with typical CZE-UVanalysis. The calibration curve was linear in the range from 0.2 to 15.0 μg/mL for both strychnine and brucine, with correlation coefficients of 0.9984 and 0.9976, respectively. The limits of detection (S/N=3:1) for strychnine and brucine were 0.02 and 0.05 μg/mL, respectively. The MSS-CZE method has been successfully applied to the analysis of strychnine and brucine in Chinese medicinal preparations.
2011, 22(3): 334-337
doi: 10.1016/j.cclet.2010.09.035
Abstract:
In this study, a simple and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established and validated to determine the 14 β-lactam antibiotics in cosmetic products, including 1 (ceftazidime), 2 (cefaclor), 3 (cefdinir), 4 (ampicillin), 5 (cefalexin), 6 (ceftezole), 7 (cefotaxim), 8 (cefradine), 9 (cefuroxime), 10 (cephazoline), 11 (cefathiamidine), 12 (cefoperazone), 13 (cafalotin), 14 (piperacillin).
In this study, a simple and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established and validated to determine the 14 β-lactam antibiotics in cosmetic products, including 1 (ceftazidime), 2 (cefaclor), 3 (cefdinir), 4 (ampicillin), 5 (cefalexin), 6 (ceftezole), 7 (cefotaxim), 8 (cefradine), 9 (cefuroxime), 10 (cephazoline), 11 (cefathiamidine), 12 (cefoperazone), 13 (cafalotin), 14 (piperacillin).
2011, 22(3): 338-341
doi: 10.1016/j.cclet.2010.10.007
Abstract:
Green fluorescent protein (GFP) plasmid was caged by 8-bromo-7-hydroxyquinolinyl chromophore (BHQ) for controlling its expression with exact spatiotemporal resolution. In vitro and in vivo experiments clearly verified that, comparing with Bhc caging, the expression level of caged GFP plasmid was dramatically decreased and then efficiently restored after subsequent photolysis.
Green fluorescent protein (GFP) plasmid was caged by 8-bromo-7-hydroxyquinolinyl chromophore (BHQ) for controlling its expression with exact spatiotemporal resolution. In vitro and in vivo experiments clearly verified that, comparing with Bhc caging, the expression level of caged GFP plasmid was dramatically decreased and then efficiently restored after subsequent photolysis.
2011, 22(3): 342-345
doi: 10.1016/j.cclet.2010.10.008
Abstract:
A simple, fast, precise and eco-friendly analytical method for the determination of uric acid (UA) in human urine by ion chromatography (IC) was established. The sample pretreatment was not required, only needed centrifugation and filtration. The separation was carried out on a cation exchange column with 2.0 mmol/L nitric acid as mobile phase at the flow-rate 1.0 mL/min. A non-suppressed conductivity detector was used. The IC analysis time for one run was within 10 min under the optimized IC condition. The detection limits were 0.5 μg/L(S/N=3) for uric acid. The recovery was 100.1% while the relative standard deviation (RSD) was 1.8% from 10 measurements.
A simple, fast, precise and eco-friendly analytical method for the determination of uric acid (UA) in human urine by ion chromatography (IC) was established. The sample pretreatment was not required, only needed centrifugation and filtration. The separation was carried out on a cation exchange column with 2.0 mmol/L nitric acid as mobile phase at the flow-rate 1.0 mL/min. A non-suppressed conductivity detector was used. The IC analysis time for one run was within 10 min under the optimized IC condition. The detection limits were 0.5 μg/L(S/N=3) for uric acid. The recovery was 100.1% while the relative standard deviation (RSD) was 1.8% from 10 measurements.
2011, 22(3): 346-349
doi: 10.1016/j.cclet.2010.07.037
Abstract:
In this study, a new Er3+ sensor based on N-(benzyloxycarbonyloxy)succinimide (BCS) as a neutral carrier has been constructed. The sensor exhibits potential linear response with a Nernstian slope of 20.5 ±0.4 mV/decade in the concentration range of 1.0×10-6 to 1.0×10-2 mol/L of Er3+. It has a very short response time (<10 s), detection limit of 6.3×10-7 mol/L and a good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy, and transition metal ions. It can be used in the pH range of 2.5-10.6 without any considerable divergence in potentials. The proposed sensor was successfully applied for the recovery of Er3+ ions spiked in tap and river water samples.
In this study, a new Er3+ sensor based on N-(benzyloxycarbonyloxy)succinimide (BCS) as a neutral carrier has been constructed. The sensor exhibits potential linear response with a Nernstian slope of 20.5 ±0.4 mV/decade in the concentration range of 1.0×10-6 to 1.0×10-2 mol/L of Er3+. It has a very short response time (<10 s), detection limit of 6.3×10-7 mol/L and a good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy, and transition metal ions. It can be used in the pH range of 2.5-10.6 without any considerable divergence in potentials. The proposed sensor was successfully applied for the recovery of Er3+ ions spiked in tap and river water samples.
2011, 22(3): 350-353
doi: 10.1016/j.cclet.2010.10.025
Abstract:
This work described a sensitive method for determination of metoprolol in rabbit plasma. The method involved purification by ultrafiltration, derivatization with fluorescein isothiocyanate, determination by capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detector. Other components in plasma including a variety of amino acids and proteins did not interfere with the determination of metoprolol in experimental condition. The assay had a wide range (2.0-500 ng/mL) of linearity and a detection limit of 0.8 ng/mL. The intra-and inter-day precisions were satisfactory with relative standard deviation (RSD) less than 10.0% and accuracy within 10.0%. This method was successfully applied to pharmacokinetic study of metoprolol in rabbit blood.
This work described a sensitive method for determination of metoprolol in rabbit plasma. The method involved purification by ultrafiltration, derivatization with fluorescein isothiocyanate, determination by capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detector. Other components in plasma including a variety of amino acids and proteins did not interfere with the determination of metoprolol in experimental condition. The assay had a wide range (2.0-500 ng/mL) of linearity and a detection limit of 0.8 ng/mL. The intra-and inter-day precisions were satisfactory with relative standard deviation (RSD) less than 10.0% and accuracy within 10.0%. This method was successfully applied to pharmacokinetic study of metoprolol in rabbit blood.
2011, 22(3): 354-357
doi: 10.1016/j.cclet.2010.10.027
Abstract:
In this work, we propose a new spin-coating method coupling with high thermal decomposition, to prepare the tin-antimony (Sn-Sb) oxide electrode. The character of the spin-coating electrode was compared with the dip-coating electrode through X-ray diffraction (XRD), scanning electron microscopy (SEM), accelerated life test, cyclic voltammetry, and electrolytic degradability. The results showed that the spin-coating electrode had a better defined crystal form, a smoother and more compact surface than that of the dip-coating electrode. Service time of the spin-coating electrode was determined to be longer than 15 h, and it was less than 2 min for the dip-coating electrode. Electrochemical characterization analysis showed that the electrolytic degradability of the spin-coating electrode is better than that of the dip-coating electrode.
In this work, we propose a new spin-coating method coupling with high thermal decomposition, to prepare the tin-antimony (Sn-Sb) oxide electrode. The character of the spin-coating electrode was compared with the dip-coating electrode through X-ray diffraction (XRD), scanning electron microscopy (SEM), accelerated life test, cyclic voltammetry, and electrolytic degradability. The results showed that the spin-coating electrode had a better defined crystal form, a smoother and more compact surface than that of the dip-coating electrode. Service time of the spin-coating electrode was determined to be longer than 15 h, and it was less than 2 min for the dip-coating electrode. Electrochemical characterization analysis showed that the electrolytic degradability of the spin-coating electrode is better than that of the dip-coating electrode.
2011, 22(3): 358-361
doi: 10.1016/j.cclet.2010.10.015
Abstract:
The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline (PCA) in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations. The PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was excessive. The pseudo-first-order rate constants of PCA degradation by persulfate (50 mmol/L) at pH 7.0 are 0.12×10-4, 0.28×10-4,0.43×10-4, 0.83×10-4, 1.32×10-4 s-1 at 10, 20, 30, 40 and 50℃, respectively. Under the above reaction conditions, the reaction has activation energy of 49.97 kJ/mol. The observed rate was found to be function of temperature and oxidant concentration. Raising temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.
The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline (PCA) in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations. The PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was excessive. The pseudo-first-order rate constants of PCA degradation by persulfate (50 mmol/L) at pH 7.0 are 0.12×10-4, 0.28×10-4,0.43×10-4, 0.83×10-4, 1.32×10-4 s-1 at 10, 20, 30, 40 and 50℃, respectively. Under the above reaction conditions, the reaction has activation energy of 49.97 kJ/mol. The observed rate was found to be function of temperature and oxidant concentration. Raising temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.
2011, 22(3): 362-365
doi: 10.1016/j.cclet.2010.10.006
Abstract:
The Cu/SiO2 catalysts were in situ synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS) in one phase solution using ethanol as co-solvent or TEOS/H2O two phases solution, followed by the precipitation of copper on SiO2 by ammonia evaporation. In the hydrogenation of dimethyl oxalate, the catalyst prepared by one phase hydrolysis exhibited higher activity and ethylene glycol (EG) selectivity at lower temperature than that of two phases due to its larger BET surface area and multimodal pore distribution. At 488-503 K, the catalyst prepared in one phase solution with water/ethanol (W/E) volume ratio of 3:1 exhibited 90-95% EG selectivity, while catalyst prepared by two phase hydrolysis reached 90% EG selectivity only at 498-503 K.
The Cu/SiO2 catalysts were in situ synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS) in one phase solution using ethanol as co-solvent or TEOS/H2O two phases solution, followed by the precipitation of copper on SiO2 by ammonia evaporation. In the hydrogenation of dimethyl oxalate, the catalyst prepared by one phase hydrolysis exhibited higher activity and ethylene glycol (EG) selectivity at lower temperature than that of two phases due to its larger BET surface area and multimodal pore distribution. At 488-503 K, the catalyst prepared in one phase solution with water/ethanol (W/E) volume ratio of 3:1 exhibited 90-95% EG selectivity, while catalyst prepared by two phase hydrolysis reached 90% EG selectivity only at 498-503 K.
2011, 22(3): 366-369
doi: 10.1016/j.cclet.2010.10.045
Abstract:
The CoMo/Al2O3 catalysts with different metal loading were studied by low temperature in situ FT-IR using CO as probe molecule which appears to be a powerful method by giving rise to signals specific for unpromoted and promoted Mo sites. The result revealed that the increase of C0M0S phase on the catalyst surface improves the HDS activity and selectivity. The ratio of active site number of CoMoS and MoS2 correlates linearly with HDS selectivity, which provides an effective tool for developing industrial selective HDS catalysts.
The CoMo/Al2O3 catalysts with different metal loading were studied by low temperature in situ FT-IR using CO as probe molecule which appears to be a powerful method by giving rise to signals specific for unpromoted and promoted Mo sites. The result revealed that the increase of C0M0S phase on the catalyst surface improves the HDS activity and selectivity. The ratio of active site number of CoMoS and MoS2 correlates linearly with HDS selectivity, which provides an effective tool for developing industrial selective HDS catalysts.
2011, 22(3): 370-373
doi: 10.1016/j.cclet.2010.10.017
Abstract:
Well-defined amphiphilic tri-block copolymer PVP-b-PMMA-b-PVP was prepared for the first time via successive reversible addition fragmentation chain transfer (RAFT) polymerization using carboxyl-terminated trithiocarbonate as the RAFT agent. The structure of the copolymer was characterized using FTTR, GPC and 1H NMR. The block copolymer could be directly blended with polyethersulfone (PES) as a macromolecule additive using N-methyl-2-pyrrolidone (NMP) as the solvent to prepare membranes. The water contact angles for the modified membranes decreased obviously, and therefore, the protein adsorption amount on the membrane surface decreased.
Well-defined amphiphilic tri-block copolymer PVP-b-PMMA-b-PVP was prepared for the first time via successive reversible addition fragmentation chain transfer (RAFT) polymerization using carboxyl-terminated trithiocarbonate as the RAFT agent. The structure of the copolymer was characterized using FTTR, GPC and 1H NMR. The block copolymer could be directly blended with polyethersulfone (PES) as a macromolecule additive using N-methyl-2-pyrrolidone (NMP) as the solvent to prepare membranes. The water contact angles for the modified membranes decreased obviously, and therefore, the protein adsorption amount on the membrane surface decreased.
2011, 22(3): 374-377
doi: 10.1016/j.cclet.2010.10.028
Abstract:
A novel divinyl ether was synthesized by a convenient method with high yield. Then the divinyl ether was combined with 2-hydroxyethyl methacrylate and acrylic acid, respectively, generating difunctional polymeric crosslinkers with (hemi) acetal structure that was labile in acid. The chemical structures of the divinyl ether and crosslinkers were confirmed by 1H NMR and elemental analysis. The crosslinkers were employed in free-radical polymerization to prepare polymer gel and gel particles. Due to the (hemi)acetal structure in the crosslinking segment, the polymer gel and particles exhibited degradable ability in strong acid.
A novel divinyl ether was synthesized by a convenient method with high yield. Then the divinyl ether was combined with 2-hydroxyethyl methacrylate and acrylic acid, respectively, generating difunctional polymeric crosslinkers with (hemi) acetal structure that was labile in acid. The chemical structures of the divinyl ether and crosslinkers were confirmed by 1H NMR and elemental analysis. The crosslinkers were employed in free-radical polymerization to prepare polymer gel and gel particles. Due to the (hemi)acetal structure in the crosslinking segment, the polymer gel and particles exhibited degradable ability in strong acid.
