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2009 Volume 20 Issue 9
2009, 20(9): 1015-1016
doi: 10.1016/j.cclet.2009.04.037
Abstract:
A regio- and stereo-selective synthesis of multi-substituted 3-pyrrolines has been developed. The multi-substituted 3-pyrrolines were synthesized in good yields by 1,3-dipolar cycloaddition of methyl 2-(phenylselanyl)acrylate with azomethine ylides, followed by N-acylation and oxidation-elimination of phenylseleno group.
A regio- and stereo-selective synthesis of multi-substituted 3-pyrrolines has been developed. The multi-substituted 3-pyrrolines were synthesized in good yields by 1,3-dipolar cycloaddition of methyl 2-(phenylselanyl)acrylate with azomethine ylides, followed by N-acylation and oxidation-elimination of phenylseleno group.
2009, 20(9): 1017-1018
doi: 10.1016/j.cclet.2009.03.010
Abstract:
3,4-Epoxybisabola-7(14),10-dien-2-one, a natural sesquiterpoind, was first synthesized from (-)-carvone through 7 steps, in an overall yield of 35.9%. The key step was the allylation and then a substrate-directable epoxidation was committed successfully.Mycobacterium tuberculosis FabH, an essential enzyme in mycolic acids biosynthetic pathway, is an attractive target for novel anti-tuberculosis agents. Structure-based design, synthesis of novel inhibitors of mtFabH was reported in this paper. A novel scaffold structure was designed, and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.
3,4-Epoxybisabola-7(14),10-dien-2-one, a natural sesquiterpoind, was first synthesized from (-)-carvone through 7 steps, in an overall yield of 35.9%. The key step was the allylation and then a substrate-directable epoxidation was committed successfully.Mycobacterium tuberculosis FabH, an essential enzyme in mycolic acids biosynthetic pathway, is an attractive target for novel anti-tuberculosis agents. Structure-based design, synthesis of novel inhibitors of mtFabH was reported in this paper. A novel scaffold structure was designed, and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.
2009, 20(9): 1019-1022
doi: 10.1016/j.cclet.2009.04.018
Abstract:
Mycobacterium tuberculosis FabH, an essential enzyme in mycolic acids biosynthetic pathway, is an attractive target for novel anti-tuberculosis agents. Structure-based design, synthesis of novel inhibitors of mtFabH was reported in this paper. A novel scaffold structure was designed, and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.
Mycobacterium tuberculosis FabH, an essential enzyme in mycolic acids biosynthetic pathway, is an attractive target for novel anti-tuberculosis agents. Structure-based design, synthesis of novel inhibitors of mtFabH was reported in this paper. A novel scaffold structure was designed, and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.
2009, 20(9): 1023-1025
doi: 10.1016/j.cclet.2009.04.029
Abstract:
The synthesis of racemic cedarmycin B, an antibiotic from Streptomyces sp. TP-A0456 was achieved firstly from γ-butyrolactone.The key step was a Barbier-type addition of 3-bromomethyl-5H-furan-2-one to formaldehyde mediated by zinc,which afforded the sole g-addition product 4-hydroxymethyl-3-methylene-dihydrofuran-2-one. The final compound was confirmed by 1H NMR,13C NMR and HRMS.
The synthesis of racemic cedarmycin B, an antibiotic from Streptomyces sp. TP-A0456 was achieved firstly from γ-butyrolactone.The key step was a Barbier-type addition of 3-bromomethyl-5H-furan-2-one to formaldehyde mediated by zinc,which afforded the sole g-addition product 4-hydroxymethyl-3-methylene-dihydrofuran-2-one. The final compound was confirmed by 1H NMR,13C NMR and HRMS.
2009, 20(9): 1026-1029
doi: 10.1016/j.cclet.2009.04.015
Abstract:
A highly effective and mild protocol for ring opening of epoxides with NH 4 SCN in the presence of catalytic amount of a multisite phase-transfer catalyst, α,α',α" -N-hexakis(triethylammoniummethylene chloride)-melamine, is developed. A variety of b-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times.
A highly effective and mild protocol for ring opening of epoxides with NH 4 SCN in the presence of catalytic amount of a multisite phase-transfer catalyst, α,α',α" -N-hexakis(triethylammoniummethylene chloride)-melamine, is developed. A variety of b-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times.
2009, 20(9): 1030-1033
doi: 10.1016/j.cclet.2009.05.009
Abstract:
Twelve 23-esterified silybin derivatives with different patterns of substituents such as aromatic and aliphatic groups (1-12) were designed and synthesized. The antioxidative properties of these compounds were evaluated. The modified silybin analogues exhibited improved inhibitory effects against rat liver homogenate lipid peroxidation compared to silybin, with exception of the trimethoxylated ester (5) and the aliphatic one (9). Compounds 3, 5, 7, 8 and 11 displayed their protective properties on DNA cleavage in a dose-dependent manner.
Twelve 23-esterified silybin derivatives with different patterns of substituents such as aromatic and aliphatic groups (1-12) were designed and synthesized. The antioxidative properties of these compounds were evaluated. The modified silybin analogues exhibited improved inhibitory effects against rat liver homogenate lipid peroxidation compared to silybin, with exception of the trimethoxylated ester (5) and the aliphatic one (9). Compounds 3, 5, 7, 8 and 11 displayed their protective properties on DNA cleavage in a dose-dependent manner.
2009, 20(9): 1034-1038
doi: 10.1016/j.cclet.2009.05.008
Abstract:
Ferrous methanesulfonate catalysing the conversion of aromatic, heteroaromatic, unsaturated, and aliphatic aldehydes to 1,1- diacetates at room temperature under solvent-free condition has been developed. The catalytic activity of seventeen metal methanesulfonates was compared under the same condition, ferrous methanesufonate proved to be the best. It can be easily recovered and reused for several times without distinct deterioration in catalytic activity. During the competitive protection between a ketone and an aldehyde group with Ac 2 O, 1,1-diacetate formed exclusively with the aldehyde group.
Ferrous methanesulfonate catalysing the conversion of aromatic, heteroaromatic, unsaturated, and aliphatic aldehydes to 1,1- diacetates at room temperature under solvent-free condition has been developed. The catalytic activity of seventeen metal methanesulfonates was compared under the same condition, ferrous methanesufonate proved to be the best. It can be easily recovered and reused for several times without distinct deterioration in catalytic activity. During the competitive protection between a ketone and an aldehyde group with Ac 2 O, 1,1-diacetate formed exclusively with the aldehyde group.
2009, 20(9): 1039-1041
doi: 10.1016/j.cclet.2009.04.008
Abstract:
A novel redox calix[4]arene derivative with 1,3-substituted large conjugated ferrocene bridge was designed and synthesized in high yield. Its structure was characterized by element analysis, IR, ESI-MS, NMR spectrum, etc. The primary study of cyclic voltammetry showed it possessed excellent reversible electrochemistry response property.
A novel redox calix[4]arene derivative with 1,3-substituted large conjugated ferrocene bridge was designed and synthesized in high yield. Its structure was characterized by element analysis, IR, ESI-MS, NMR spectrum, etc. The primary study of cyclic voltammetry showed it possessed excellent reversible electrochemistry response property.
2009, 20(9): 1042-1046
doi: 10.1016/j.cclet.2009.04.024
Abstract:
Alum (KAl(SO 4) 2·12H 2O) is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminophosphonates.A three component reaction of an aldehyde/ketone, an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding a-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.
Alum (KAl(SO 4) 2·12H 2O) is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminophosphonates.A three component reaction of an aldehyde/ketone, an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding a-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.
2009, 20(9): 1047-1050
doi: 10.1016/j.cclet.2009.03.017
Abstract:
A blue light-emitting material, 2-(N-ethyl-anthraceneyl-9) imidazo [4,5-f] 1,10-phenanthroline (EAIP), has been synthesized and characterized by 1H NMR, IR, elemental and single crystal X-ray diffraction analysis. The results of theoretical calculations indicate that the HOMO and LUMO distributions mainly locate at the anthracene fragment. It displays bright blue emission in both solid state and dichloromethane solution. The emission quantum yield calculated is 0.76.
A blue light-emitting material, 2-(N-ethyl-anthraceneyl-9) imidazo [4,5-f] 1,10-phenanthroline (EAIP), has been synthesized and characterized by 1H NMR, IR, elemental and single crystal X-ray diffraction analysis. The results of theoretical calculations indicate that the HOMO and LUMO distributions mainly locate at the anthracene fragment. It displays bright blue emission in both solid state and dichloromethane solution. The emission quantum yield calculated is 0.76.
2009, 20(9): 1051-1054
doi: 10.1016/j.cclet.2009.04.011
Abstract:
A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites, which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes, was synthesized by postgrafting of 1,5,7- triazabicyclo[4.4.0] dec-5-ene (TBD, a sterically hindered organic base) onto Al-MCM-41 molecular sieve.
A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites, which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes, was synthesized by postgrafting of 1,5,7- triazabicyclo[4.4.0] dec-5-ene (TBD, a sterically hindered organic base) onto Al-MCM-41 molecular sieve.
2009, 20(9): 1055-1058
doi: 10.1016/j.cclet.2009.04.004
Abstract:
5,6-Dihydrothieno[3',2':4,5]thieno[2,3-d]pyrimidin-4(3H)-ones 6 were synthesized in yields of 71-87% by a consecutive method, which includes aza-Wittig reaction of iminophosphorane 3 with aromatic isocynate to give carbodiimide 4 and subsequent reaction of 4 with various amines, phenols or alcohols in the presence of catalytic amount of sodium ethoxide or solid potassium carbonate.
5,6-Dihydrothieno[3',2':4,5]thieno[2,3-d]pyrimidin-4(3H)-ones 6 were synthesized in yields of 71-87% by a consecutive method, which includes aza-Wittig reaction of iminophosphorane 3 with aromatic isocynate to give carbodiimide 4 and subsequent reaction of 4 with various amines, phenols or alcohols in the presence of catalytic amount of sodium ethoxide or solid potassium carbonate.
2009, 20(9): 1059-1061
doi: 10.1016/j.cclet.2009.03.024
Abstract:
An efficient synthesis of benzoxazole-substituted 3,4-dihydropyrimidinones (DHPMs) using trifluoro acetic acid as the catalyst for the first time from an aldehyde, b-keto ester and benzoxazole-substituted urea/thiourea under solvent-free conditions is described. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of excellent yields (80-91%) and short reaction time (40-130 min) at reflux temperature.
An efficient synthesis of benzoxazole-substituted 3,4-dihydropyrimidinones (DHPMs) using trifluoro acetic acid as the catalyst for the first time from an aldehyde, b-keto ester and benzoxazole-substituted urea/thiourea under solvent-free conditions is described. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of excellent yields (80-91%) and short reaction time (40-130 min) at reflux temperature.
2009, 20(9): 1061-1064
doi: 10.1016/j.cclet.2009.04.017
Abstract:
The total synthesis of (±)-8-(3-methylbut-2-enyl)-2-phenyl-2,3-dihydrochromen-4-one and (±)-2-(4-hydroxyphenyl)-8-(3-methylbut-2-enyl)-2,3-dihydrochromen-4-one was first achieved through C-prenylation, protection of phenolic hydroxyl group aldol condensation, cyclization and deprotection starting from cheap benzaldehyde, 4-hydroxybenzaldehyde and 2-hydroxyacetophenone,with total yield of 20 and 16.3%. All structures of new compounds were confirmed by IR,1H NMR and MS.
The total synthesis of (±)-8-(3-methylbut-2-enyl)-2-phenyl-2,3-dihydrochromen-4-one and (±)-2-(4-hydroxyphenyl)-8-(3-methylbut-2-enyl)-2,3-dihydrochromen-4-one was first achieved through C-prenylation, protection of phenolic hydroxyl group aldol condensation, cyclization and deprotection starting from cheap benzaldehyde, 4-hydroxybenzaldehyde and 2-hydroxyacetophenone,with total yield of 20 and 16.3%. All structures of new compounds were confirmed by IR,1H NMR and MS.
2009, 20(9): 1065-1067
doi: 10.1016/j.cclet.2009.04.034
Abstract:
MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes, which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses.
MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes, which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses.
2009, 20(9): 1068-1072
doi: 10.1016/j.cclet.2009.04.033
Abstract:
Activated methylene compound such as dimethyl malonate reacted readily with benzylic alcohols in the presence of ferric chloride/silica gel mixture (FeCl3/SiO2) under microwave irradiation to produce benzylic derivative of dimethyl malonate in high yields in solvent-free condition.
Activated methylene compound such as dimethyl malonate reacted readily with benzylic alcohols in the presence of ferric chloride/silica gel mixture (FeCl3/SiO2) under microwave irradiation to produce benzylic derivative of dimethyl malonate in high yields in solvent-free condition.
2009, 20(9): 1073-1076
doi: 10.1016/j.cclet.2009.04.016
Abstract:
N-(4-Methyl-3-tolylthiazol-2(3H)-ylidene) substituted benzamides (2a-o) were synthesized in good to excellent yields by the base-catalyzed direct cyclization of corresponding 1-tolyl-3-aryl thioureas (1a-o) with 2-bromoacetone through microwave irradiation in a solvent-free medium. Compared to traditional thermal heating, microwave irradiation provides a much more cleaner, efficient and faster method for synthesis of the title compounds.
N-(4-Methyl-3-tolylthiazol-2(3H)-ylidene) substituted benzamides (2a-o) were synthesized in good to excellent yields by the base-catalyzed direct cyclization of corresponding 1-tolyl-3-aryl thioureas (1a-o) with 2-bromoacetone through microwave irradiation in a solvent-free medium. Compared to traditional thermal heating, microwave irradiation provides a much more cleaner, efficient and faster method for synthesis of the title compounds.
2009, 20(9): 1077-1080
doi: 10.1016/j.cclet.2009.04.013
Abstract:
The dimesogenic compound consisting of cholesterol and cyanobiphenyl mesogens interlinked by ω-oxyalkanoyl spacer was synthesized. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). The experimental results indicated that this compound exhibited mesophase over a much wider temperature range and a new mesophase blue phase (BP). Focal conic domains (FCDs) and droplets texture to the smectic A phase (SA), oily streaks typical to the chiral nematic (N*) phase were found in the liquid crystalline state, respectively. Besides, it exhibited a smectic layer spacing about 1.0 time to the length of the molecule, which indicated a monolayer type of SAordering.
The dimesogenic compound consisting of cholesterol and cyanobiphenyl mesogens interlinked by ω-oxyalkanoyl spacer was synthesized. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). The experimental results indicated that this compound exhibited mesophase over a much wider temperature range and a new mesophase blue phase (BP). Focal conic domains (FCDs) and droplets texture to the smectic A phase (SA), oily streaks typical to the chiral nematic (N*) phase were found in the liquid crystalline state, respectively. Besides, it exhibited a smectic layer spacing about 1.0 time to the length of the molecule, which indicated a monolayer type of SAordering.
2009, 20(9): 1081-1084
doi: 10.1016/j.cclet.2009.03.048
Abstract:
A homologous series of Schiff base esters, 6-methoxy-2-(2-hydroxy-4-alkanoyloxybenzylidenamino)benzothiazoles, comprising a benzothiazole moiety as the core was synthesized. All the members of this series exhibited an enantiotropic nematic phase.The azomethine linkage along with the lateral hydroxyl and terminal methoxyl groups were found to exert an effect on themesomorphic properties.
A homologous series of Schiff base esters, 6-methoxy-2-(2-hydroxy-4-alkanoyloxybenzylidenamino)benzothiazoles, comprising a benzothiazole moiety as the core was synthesized. All the members of this series exhibited an enantiotropic nematic phase.The azomethine linkage along with the lateral hydroxyl and terminal methoxyl groups were found to exert an effect on themesomorphic properties.
2009, 20(9): 1085-1087
doi: 10.1016/j.cclet.2009.05.016
Abstract:
A series of carbosilane dendrimers with acetyl end-group were synthesized. Their structures were characterized by 1H NMR, IR,and MS, respectively. Then dendrimers were coordinated with lanthanide ions (Eu 3+and Tb3+, respectively). The luminescencespectra of the complexes show narrow-width emissions in visible light region.
A series of carbosilane dendrimers with acetyl end-group were synthesized. Their structures were characterized by 1H NMR, IR,and MS, respectively. Then dendrimers were coordinated with lanthanide ions (Eu 3+and Tb3+, respectively). The luminescencespectra of the complexes show narrow-width emissions in visible light region.
2009, 20(9): 1088-1090
doi: 10.1016/j.cclet.2009.05.005
Abstract:
A new trimeric linear-type furanocoumarin, rapultririn A (1), was isolated from the underground part of Heracleum rapula. The structure of this new compound was elucidated by NMR, MS spectroscopic methods.
A new trimeric linear-type furanocoumarin, rapultririn A (1), was isolated from the underground part of Heracleum rapula. The structure of this new compound was elucidated by NMR, MS spectroscopic methods.
2009, 20(9): 1091-1093
doi: 10.1016/j.cclet.2009.04.021
Abstract:
A new cerebroside, gynuraoside (1), was isolated from the aerial parts of Gynura divaricataDC. It was determined to be 1-O-β- D-glucopyranosyl-(2S,3S,4R,10E)-2-[(2'R)-2'-hydroxyldocosanoyl-amino]-10-octadecene-1,3,4-triol on the basis of chemical and spectroscopic evidence. This compound showed strong cytotoxicity against L1210 leukemia cell line in vitro.
A new cerebroside, gynuraoside (1), was isolated from the aerial parts of Gynura divaricataDC. It was determined to be 1-O-β- D-glucopyranosyl-(2S,3S,4R,10E)-2-[(2'R)-2'-hydroxyldocosanoyl-amino]-10-octadecene-1,3,4-triol on the basis of chemical and spectroscopic evidence. This compound showed strong cytotoxicity against L1210 leukemia cell line in vitro.
2009, 20(9): 1094-1096
doi: 10.1016/j.cclet.2009.03.044
Abstract:
A new steroidal alkaloid, beaumontamine (1), was isolated from the stems of Beaumontia grandiflora. The structure waselucidated on the basis of spectral analysis.
A new steroidal alkaloid, beaumontamine (1), was isolated from the stems of Beaumontia grandiflora. The structure waselucidated on the basis of spectral analysis.
2009, 20(9): 1097-1099
doi: 10.1016/j.cclet.2009.04.006
Abstract:
Two new glycosides, nor-rubrofusarin-6-0-β-D-(6'-O-acetyl)glucopyranoside (1) and 1-desmethylaurantio-obtusin-2-O-β-Dglucopyranoside(2) were isolated from the seeds of Cassia obtusifolia and their structures were established by chemical and spectral evidences.
Two new glycosides, nor-rubrofusarin-6-0-β-D-(6'-O-acetyl)glucopyranoside (1) and 1-desmethylaurantio-obtusin-2-O-β-Dglucopyranoside(2) were isolated from the seeds of Cassia obtusifolia and their structures were established by chemical and spectral evidences.
2009, 20(9): 1100-1102
doi: 10.1016/j.cclet.2009.04.023
Abstract:
A simple aqueous two-phase extraction system (ATPS) of PEG/phosphate was proposed for selective separation and enrichment of proteins. The combination of ATPE with HPLC was applied to identify the partition of proteins in two phases. Five proteins (bovine serum albumin, Cytochrome C, lysozyme, myoglobin, and trypsin) were used as model proteins to study the effect of phosphate concentration and pH on proteins partition. The PEG/phosphate system was firstly applied to real human saliva and plasma samples, some proteins showed obviously different partition in two phases. The primary results manifest the selective separation and enrichment of proteins in ATPS provided the potential for high abundance proteins depletion in proteomics.
A simple aqueous two-phase extraction system (ATPS) of PEG/phosphate was proposed for selective separation and enrichment of proteins. The combination of ATPE with HPLC was applied to identify the partition of proteins in two phases. Five proteins (bovine serum albumin, Cytochrome C, lysozyme, myoglobin, and trypsin) were used as model proteins to study the effect of phosphate concentration and pH on proteins partition. The PEG/phosphate system was firstly applied to real human saliva and plasma samples, some proteins showed obviously different partition in two phases. The primary results manifest the selective separation and enrichment of proteins in ATPS provided the potential for high abundance proteins depletion in proteomics.
2009, 20(9): 1103-1106
doi: 10.1016/j.cclet.2009.04.022
Abstract:
A new metabonomics method was developed for simultaneous qualitative and quantitative analysis on esterified and nonesterified fatty acids (EFAs and NEFAs) in plasma. Merely 10 μL of plasma was required. The pretreatment of the sample was simple without disposing the protein. After simple extraction and derivation, 15 FAs in plasma were precisely quantified. Gas chromatography tandem mass spectrometry (GC-MS) was used in the study and the quantities of the analytes, which varied in abundance over three orders of magnitude. The established method showed good accuracy. The curve correlation coefficients were all above 0.997. The RSDs of precision for all compounds were below 15% and recoveries were all between 80 and 110%. PLS-DA modal was used in the data management.b
A new metabonomics method was developed for simultaneous qualitative and quantitative analysis on esterified and nonesterified fatty acids (EFAs and NEFAs) in plasma. Merely 10 μL of plasma was required. The pretreatment of the sample was simple without disposing the protein. After simple extraction and derivation, 15 FAs in plasma were precisely quantified. Gas chromatography tandem mass spectrometry (GC-MS) was used in the study and the quantities of the analytes, which varied in abundance over three orders of magnitude. The established method showed good accuracy. The curve correlation coefficients were all above 0.997. The RSDs of precision for all compounds were below 15% and recoveries were all between 80 and 110%. PLS-DA modal was used in the data management.b
2009, 20(9): 1107-1110
doi: 10.1016/j.cclet.2009.03.049
Abstract:
DTPA and its two derivatives were synthesized and used as catalysts in DNA cleavage. Under physiological conditions, a seriesof experiments have been done. The effects of DNA cleavage with three ligands were studied under different concentrations,cleavage time, and pH values. The results strongly suggested that the plasmid DNA (pUC 19) can be cleaved efficiently by CITC- DTPA. For the cleavage reaction catalyzed by CITC-DTPA, Form I DNA could convert to Form Ⅱ mostly, and the DNA-cleavage mechanism involved an oxidative pathway.
DTPA and its two derivatives were synthesized and used as catalysts in DNA cleavage. Under physiological conditions, a seriesof experiments have been done. The effects of DNA cleavage with three ligands were studied under different concentrations,cleavage time, and pH values. The results strongly suggested that the plasmid DNA (pUC 19) can be cleaved efficiently by CITC- DTPA. For the cleavage reaction catalyzed by CITC-DTPA, Form I DNA could convert to Form Ⅱ mostly, and the DNA-cleavage mechanism involved an oxidative pathway.
2009, 20(9): 1111-1114
doi: 10.1016/j.cclet.2009.04.002
Abstract:
A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography (CGC) is described. The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane (PMHS-[VHIm][PF 6]) was synthesized,characterized and coated onto capillary columns by static coating. The results show that the present stationary phase exhibits avery good chromatographic resolution and selectivity for Grob test mixture and alcohols with baseline resolution and symmetry peaks.The present work suggests that novel stationary phase has a great potential for further development and application.
A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography (CGC) is described. The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane (PMHS-[VHIm][PF 6]) was synthesized,characterized and coated onto capillary columns by static coating. The results show that the present stationary phase exhibits avery good chromatographic resolution and selectivity for Grob test mixture and alcohols with baseline resolution and symmetry peaks.The present work suggests that novel stationary phase has a great potential for further development and application.
2009, 20(9): 1115-1118
doi: 10.1016/j.cclet.2009.04.035
Abstract:
The effect of an adsorbed anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on electron transfer (ET) reaction between ferricyanide aqueous solution and decamethylferrocene (DMFc) located on the adjacent organic phase was investigated for the first time by thin layer method. The adsorption of SDBS at the interface resulted in a decay in the cathodic plateau current of bimolecular reaction with increasing concentrations of SDBS in aqueous phase. However, the rate constant of electron transfer (ket)increased monotonically as the SDBS concentrations increased from 0 to 200 μmol/L. The experimental results showed that SDBS formed patches on the interface and influenced the structure of electrical double layer.
The effect of an adsorbed anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on electron transfer (ET) reaction between ferricyanide aqueous solution and decamethylferrocene (DMFc) located on the adjacent organic phase was investigated for the first time by thin layer method. The adsorption of SDBS at the interface resulted in a decay in the cathodic plateau current of bimolecular reaction with increasing concentrations of SDBS in aqueous phase. However, the rate constant of electron transfer (ket)increased monotonically as the SDBS concentrations increased from 0 to 200 μmol/L. The experimental results showed that SDBS formed patches on the interface and influenced the structure of electrical double layer.
2009, 20(9): 1119-1122
doi: 10.1016/j.cclet.2009.04.020
Abstract:
In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates.Capillary elect correlation spectroscopy (FCS) were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution.
In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates.Capillary elect correlation spectroscopy (FCS) were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution.
2009, 20(9): 1123-1126
doi: 10.1016/j.cclet.2009.04.005
Abstract:
In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates.Capillary elect correlation spectroscopy (FCS) were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution.
In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates.Capillary elect correlation spectroscopy (FCS) were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution.
2009, 20(9): 1127-1130
doi: 10.1016/j.cclet.2009.03.012
Abstract:
Fluorinated poly(ethylene oxide) propyl-b-polydimethylsiloxane-b-propyl fluorinated poly(ethylene oxide) (FPEO-b-PDMS-b-FPEO) was synthesized by a free radical addition of carbon–hydrogen of polyether segments of poly(ethylene oxide) propyl-bpolydimethylsiloxane-b-propyl poly(ethylene oxide) (PEO-b-PDMS-b-PEO) to hexafluoropropylene (HFP) using tert-butyl peroxypivalate as an initiator. In order to reduce the possibility of side reaction, the protection and deprotection via silylation were used for the end-hydroxyls in PEO-b-PDMS-b-PEO chain. The structure of Intermediates and FPEO-b-PDMS-b-FPEO was confirmed by means of Fourier transform infrared and 1H NMR spectroscopy. The effects of amount of initiator, reaction temperature and time on free radical addition were investigated in detail.
Fluorinated poly(ethylene oxide) propyl-b-polydimethylsiloxane-b-propyl fluorinated poly(ethylene oxide) (FPEO-b-PDMS-b-FPEO) was synthesized by a free radical addition of carbon–hydrogen of polyether segments of poly(ethylene oxide) propyl-bpolydimethylsiloxane-b-propyl poly(ethylene oxide) (PEO-b-PDMS-b-PEO) to hexafluoropropylene (HFP) using tert-butyl peroxypivalate as an initiator. In order to reduce the possibility of side reaction, the protection and deprotection via silylation were used for the end-hydroxyls in PEO-b-PDMS-b-PEO chain. The structure of Intermediates and FPEO-b-PDMS-b-FPEO was confirmed by means of Fourier transform infrared and 1H NMR spectroscopy. The effects of amount of initiator, reaction temperature and time on free radical addition were investigated in detail.
2009, 20(9): 1131-1135
doi: 10.1016/j.cclet.2009.04.003
Abstract:
A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride (PD-SnCl 3 ) was prepared by the reaction of n-butyl-Li (n-BuLi), stannic chloride (SnCl4) and diene. Then PD-SnCl 3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators. The result suggested that the initiators had a remarkable yield by GPC, nearly 90%. By using these multifunctional macromolecular initiators, styrene and butadiene were effectively polymerized via anionic polymerization, which gave birth to novel miktoarm star copolymers. The relative molecular weight and polydispersity index, microstructure contents, copolymerization components, glass transition temperature (Tg) and morphology of the miktoarm star copolymers were investigated by GPC-UV,1H NMR, DSC and TEM, respectively.
A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride (PD-SnCl 3 ) was prepared by the reaction of n-butyl-Li (n-BuLi), stannic chloride (SnCl4) and diene. Then PD-SnCl 3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators. The result suggested that the initiators had a remarkable yield by GPC, nearly 90%. By using these multifunctional macromolecular initiators, styrene and butadiene were effectively polymerized via anionic polymerization, which gave birth to novel miktoarm star copolymers. The relative molecular weight and polydispersity index, microstructure contents, copolymerization components, glass transition temperature (Tg) and morphology of the miktoarm star copolymers were investigated by GPC-UV,1H NMR, DSC and TEM, respectively.
2009, 20(9): 1136-1140
doi: 10.1016/j.cclet.2009.04.012
Abstract:
To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer (RAFT) process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures.The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation.
To make more homogenous organic monolithic structure, reversible addition-fragmentation chain transfer (RAFT) process was employed in the synthesis of the clenbuterol imprinted polymer. In the synthesis, the influence of synthetic conditions on the polymer structure and separation efficiency was studied. The result demonstrated that the imprinted columns prepared with RAFT process have higher column efficiency and selectivity than the columns prepared with conventional polymerization in the present study, which may result from the higher surface area, smaller pore size and the narrower globule size distribution in their structures.The result indicated that RAFT polymerization provided better conditions for the clenbuterol imprinted monolithic polymer preparation.
