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2007 Volume 18 Issue 1
2007, 18(1): 1-3
doi: 10.1016/j.cclet.2006.11.001
Abstract:
A novel facile procedure for traceless solid-phase synthesis of 3-substituted isoxazoles in good yields and with excellent purities using polymer-supported vinyl selenide has been developed.
A novel facile procedure for traceless solid-phase synthesis of 3-substituted isoxazoles in good yields and with excellent purities using polymer-supported vinyl selenide has been developed.
2007, 18(1): 4-6
doi: 10.1016/j.cclet.2006.11.036
Abstract:
Sn-aniline complex was prepared by a simple procedure. Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.
Sn-aniline complex was prepared by a simple procedure. Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.
2007, 18(1): 7-9
doi: 10.1016/j.cclet.2006.11.031
Abstract:
Based on the structure-activity relationships and antiangiogenic mechanism of RGD-containing peptides, a series of 5-amino-1,3-dihydro-1,3-dioxo-2H-isoindole derivatives were synthesized. The structures were characterized by 1H NMR, MS and elementary analysis. There ability to inhibit angiogenesis were evaluated by chick embryo chorioallantoic membrane assay at 10-5 mol/L. Compounds 7a and 7b displayed obvious antiangiogenic activity.
Based on the structure-activity relationships and antiangiogenic mechanism of RGD-containing peptides, a series of 5-amino-1,3-dihydro-1,3-dioxo-2H-isoindole derivatives were synthesized. The structures were characterized by 1H NMR, MS and elementary analysis. There ability to inhibit angiogenesis were evaluated by chick embryo chorioallantoic membrane assay at 10-5 mol/L. Compounds 7a and 7b displayed obvious antiangiogenic activity.
2007, 18(1): 10-12
doi: 10.1016/j.cclet.2006.11.009
Abstract:
The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Aminophenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship between reaction time and the reductive ratio were studied. The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions. The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygeninsensitive enzyme. The reductive products of 4-nitrophenol were determined by HPLC and MS.
The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Aminophenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship between reaction time and the reductive ratio were studied. The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions. The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygeninsensitive enzyme. The reductive products of 4-nitrophenol were determined by HPLC and MS.
2007, 18(1): 13-16
doi: 10.1016/j.cclet.2006.11.019
Abstract:
A simple Cu(OAc)2 catalyzed Sonogashira coupling protocol is presented. It was found that the couplings of a variety of aryl halides with terminal alkynes were conducted smoothly to afford the corresponding desired products in moderate to excellent yields, using Cu(OAc)2 as the catalyst and Et3N as the solvent.
A simple Cu(OAc)2 catalyzed Sonogashira coupling protocol is presented. It was found that the couplings of a variety of aryl halides with terminal alkynes were conducted smoothly to afford the corresponding desired products in moderate to excellent yields, using Cu(OAc)2 as the catalyst and Et3N as the solvent.
2007, 18(1): 17-20
doi: 10.1016/j.cclet.2006.11.021
Abstract:
The photopromoted methoxycarbonylation of olefin with methyl formate catalyzed by Co(OAc)2 at ambient conditions has been carried out. The results indicated that the reaction activity increased with the increasing temperature. Methyl formate decomposed into CO and CH3OH firstly under irradiation, and then the methoxycarbonylation of olefin proceeded under catalysis of Co(OAc)2.The mechanism of methyl formate participating in the methoxycarbonylation is verified by the IR analysis and the labeling experiments of CD3OD and CH318OH.
The photopromoted methoxycarbonylation of olefin with methyl formate catalyzed by Co(OAc)2 at ambient conditions has been carried out. The results indicated that the reaction activity increased with the increasing temperature. Methyl formate decomposed into CO and CH3OH firstly under irradiation, and then the methoxycarbonylation of olefin proceeded under catalysis of Co(OAc)2.The mechanism of methyl formate participating in the methoxycarbonylation is verified by the IR analysis and the labeling experiments of CD3OD and CH318OH.
2007, 18(1): 21-23
doi: 10.1016/j.cclet.2006.11.018
Abstract:
New functionalized ionic liquids, 1-carboxylmethyl-3-methylimimidazolium hexafluorophosphate or fluoborate and l-aminoethyl-3-methylimimidazolium hexafluorophosphate or fluoborate have been synthesized and investigated. The obtained amino or carboxyl-functionalized ionic liquids were all characterized by FT-IR, 1H NMR and MS (ESI) and their properties such as freezing point, viscosity, solubility, specific gravity, surface tension, and interfacial tension were also determined.
New functionalized ionic liquids, 1-carboxylmethyl-3-methylimimidazolium hexafluorophosphate or fluoborate and l-aminoethyl-3-methylimimidazolium hexafluorophosphate or fluoborate have been synthesized and investigated. The obtained amino or carboxyl-functionalized ionic liquids were all characterized by FT-IR, 1H NMR and MS (ESI) and their properties such as freezing point, viscosity, solubility, specific gravity, surface tension, and interfacial tension were also determined.
2007, 18(1): 24-26
doi: 10.1016/j.cclet.2006.11.023
Abstract:
Fructone (2-methyl-2-ethylacetoacetate-1,3-dioxolane), a flavouring material, has been synthesized from ethyl acetoacetate and glycol using five water-soluble Brønsted acid ionic liquids as catalysts for the first time. The used Brønsted acid ionic liquids include[Hmim]Tfa,[Hmim]Tsa,[Hmim]BF4,[Bmim]HSO4,[Bmim]H2PO4, and[Hmim]BF4 showed the highest catalytic activity for the preparation of fructone. After reaction, the product could be isolated from the reaction system automatically, and the ionic liquid could be directly reused without dehydration.
Fructone (2-methyl-2-ethylacetoacetate-1,3-dioxolane), a flavouring material, has been synthesized from ethyl acetoacetate and glycol using five water-soluble Brønsted acid ionic liquids as catalysts for the first time. The used Brønsted acid ionic liquids include[Hmim]Tfa,[Hmim]Tsa,[Hmim]BF4,[Bmim]HSO4,[Bmim]H2PO4, and[Hmim]BF4 showed the highest catalytic activity for the preparation of fructone. After reaction, the product could be isolated from the reaction system automatically, and the ionic liquid could be directly reused without dehydration.
2007, 18(1): 27-29
doi: 10.1016/j.cclet.2006.11.027
Abstract:
A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in [bmim] [BF4] was described, ionic liquid [bmim] [BF4] acted as the dual role of solvent and promoter.
A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in [bmim] [BF4] was described, ionic liquid [bmim] [BF4] acted as the dual role of solvent and promoter.
2007, 18(1): 30-32
doi: 10.1016/j.cclet.2006.11.008
Abstract:
A bolaform (BNC10) and single-headed (HNOA) amphiphilic Schiff bases containing naphthyl group were designed and their Langmuir-Blodgett films were investigated. It was found that both the LB films show acidichromism, i.e. a reversible color change upon alternatively exposing the films to HCl and NH3 gases, respectively. It was further found that the bolaform Schiff bases film could trap NH3 gas during the acidichromic process.
A bolaform (BNC10) and single-headed (HNOA) amphiphilic Schiff bases containing naphthyl group were designed and their Langmuir-Blodgett films were investigated. It was found that both the LB films show acidichromism, i.e. a reversible color change upon alternatively exposing the films to HCl and NH3 gases, respectively. It was further found that the bolaform Schiff bases film could trap NH3 gas during the acidichromic process.
2007, 18(1): 33-36
doi: 10.1016/j.cclet.2006.11.029
Abstract:
β-Allenic α-difluoromethylenephosphonic acid monoesters were prepared under mild conditions for the first time by hydrolyzing the corresponding diethyl phosphonates in aqueous sodium hydroxide solution.
β-Allenic α-difluoromethylenephosphonic acid monoesters were prepared under mild conditions for the first time by hydrolyzing the corresponding diethyl phosphonates in aqueous sodium hydroxide solution.
2007, 18(1): 37-40
doi: 10.1016/j.cclet.2006.11.030
Abstract:
Polymer-supported phosphine ligand 3b derived from ferrocene was prepared, and applied in palladium-catalyzed Suzuki-Miyaura reactions. A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields.The recycling of the polymer-bound catalyst was tested without adding palladium.
Polymer-supported phosphine ligand 3b derived from ferrocene was prepared, and applied in palladium-catalyzed Suzuki-Miyaura reactions. A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields.The recycling of the polymer-bound catalyst was tested without adding palladium.
2007, 18(1): 41-44
doi: 10.1016/j.cclet.2006.11.022
Abstract:
A series of arylpiperazinesquinazoline-2,4-diamine compounds were designed and synthesized based on pharmacophore for uro-selective α1-adrenoceptor antagonists and 3D chemical database searching. The in vitro functional analysis showed that compounds 9 and 14 showed better and similar α1-AR antagonistic activity compared with prazosin.
A series of arylpiperazinesquinazoline-2,4-diamine compounds were designed and synthesized based on pharmacophore for uro-selective α1-adrenoceptor antagonists and 3D chemical database searching. The in vitro functional analysis showed that compounds 9 and 14 showed better and similar α1-AR antagonistic activity compared with prazosin.
2007, 18(1): 45-47
doi: 10.1016/j.cclet.2006.11.032
Abstract:
A series of thiazolidinediones analogs, as PPAR modulators, were designed, synthesized and evaluated in vitro.
A series of thiazolidinediones analogs, as PPAR modulators, were designed, synthesized and evaluated in vitro.
2007, 18(1): 48-50
doi: 10.1016/j.cclet.2006.11.037
Abstract:
A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis (3-tetradecylimidazolium-1-yl) butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structure was determined by FT-IR, 1H NMR and elemental analysis.
A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis (3-tetradecylimidazolium-1-yl) butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structure was determined by FT-IR, 1H NMR and elemental analysis.
2007, 18(1): 51-54
doi: 10.1016/j.cclet.2006.11.013
Abstract:
A novel water-soluble cystine C60 derivative was synthesized in the presence of the catalyst, tetrabutylammonium hydroxide (TBAH). The product was characterized by FT-IR, UV, 1H NMR, 13C NMR, MS and elemental analysis. Furthermore, the scavenging ability to superoxygen anion radical O2·- and hydroxyl radical ·OH was studied by chemiluminescence.It was found that cystine C60 derivative showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50%inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.167 and 0.008 mg/mL, respectively.
A novel water-soluble cystine C60 derivative was synthesized in the presence of the catalyst, tetrabutylammonium hydroxide (TBAH). The product was characterized by FT-IR, UV, 1H NMR, 13C NMR, MS and elemental analysis. Furthermore, the scavenging ability to superoxygen anion radical O2·- and hydroxyl radical ·OH was studied by chemiluminescence.It was found that cystine C60 derivative showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50%inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.167 and 0.008 mg/mL, respectively.
2007, 18(1): 55-58
doi: 10.1016/j.cclet.2006.11.007
Abstract:
A novel polypeptide named as defensin CM was isolated from Chinese mistletoe, Viscum coloratum (Kom.) Nakai. The amino acid sequence was determined by the combination of Edman degradation, endoproteinase Lys-C digestion, and MALDI-TOF mass spectrometry. The primary structure was ATCSAPSGRF KGACFSSNTC SNICKTLEGL KDGHCTGLAC YCSRNC.
A novel polypeptide named as defensin CM was isolated from Chinese mistletoe, Viscum coloratum (Kom.) Nakai. The amino acid sequence was determined by the combination of Edman degradation, endoproteinase Lys-C digestion, and MALDI-TOF mass spectrometry. The primary structure was ATCSAPSGRF KGACFSSNTC SNICKTLEGL KDGHCTGLAC YCSRNC.
2007, 18(1): 59-61
doi: 10.1016/j.cclet.2006.11.004
Abstract:
From Ligularia atroviolacea, four new eremophilendiolides, 8β-hydroxy-eremophil-3,7 (11)-dien-12,8α(14,6α)-diolide (1),8β-methoxy-eremophil-3,7(11)-dien-12,8α(14,6α)-diolide (2), 8α-hydroxy-eremophil-3,7(11)-dien-12,8β(14,6α)-diolide (3) and eremophil-3,7(11),8-trien-12,8 (14,6α)-diolide (4), as well as a known diolide (5) were isolated. Their structures were elucidated on the basis of 1D and 2D NMR as well as ESI-MS spectral data.
From Ligularia atroviolacea, four new eremophilendiolides, 8β-hydroxy-eremophil-3,7 (11)-dien-12,8α(14,6α)-diolide (1),8β-methoxy-eremophil-3,7(11)-dien-12,8α(14,6α)-diolide (2), 8α-hydroxy-eremophil-3,7(11)-dien-12,8β(14,6α)-diolide (3) and eremophil-3,7(11),8-trien-12,8 (14,6α)-diolide (4), as well as a known diolide (5) were isolated. Their structures were elucidated on the basis of 1D and 2D NMR as well as ESI-MS spectral data.
2007, 18(1): 62-64
doi: 10.1016/j.cclet.2006.11.033
Abstract:
A new triterpene and a saponin, named 2α,3β,23-trihydroxyurs-20-en-28-oic acid (1) and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester (2), have been isolated from the aerial part of Centella asiatica. Their structures were elucidated by spectral methods, including 2D-NMR spectra.
A new triterpene and a saponin, named 2α,3β,23-trihydroxyurs-20-en-28-oic acid (1) and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester (2), have been isolated from the aerial part of Centella asiatica. Their structures were elucidated by spectral methods, including 2D-NMR spectra.
2007, 18(1): 65-68
doi: 10.1016/j.cclet.2006.11.024
Abstract:
A pair of diastereoisomeric furostanol saponins was obtained from the n-butanol fraction of methanol extract from Tupistra chinensis rhizomes, a folk medicine of Shennongjia Forest District of Hubei Province. Their structures were determined, on the basis of chemical and spectroscopic evidences.
A pair of diastereoisomeric furostanol saponins was obtained from the n-butanol fraction of methanol extract from Tupistra chinensis rhizomes, a folk medicine of Shennongjia Forest District of Hubei Province. Their structures were determined, on the basis of chemical and spectroscopic evidences.
2007, 18(1): 69-72
doi: 10.1016/j.cclet.2006.11.017
Abstract:
In a continual effort to search for any anti-HIV agent from traditional Chinese medicine, one new resveratrol tetramer,cararosinols B, was isolated from the ethanol extract of aerial parts of Caragana rosea. Its structure was elucidated by spectroscopic analysis and comparison with known compounds.
In a continual effort to search for any anti-HIV agent from traditional Chinese medicine, one new resveratrol tetramer,cararosinols B, was isolated from the ethanol extract of aerial parts of Caragana rosea. Its structure was elucidated by spectroscopic analysis and comparison with known compounds.
2007, 18(1): 73-75
doi: 10.1016/j.cclet.2006.11.026
Abstract:
A new eudesmane sesquiterpene glycoside, 1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β-D-glucopyranoside (2),together with a known analogue compound, 1α,6β-dihydroxy-5,10-bis-epi-eudesm-3-ene-6-O-β-D-glucopyranoside (1), were isolated from the roots of Parepigynum funingense. The structure of 2 was determined by 1D and 2D NMR spectroscopy. Compound 1 was isolated from this plant for the first time.
A new eudesmane sesquiterpene glycoside, 1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β-D-glucopyranoside (2),together with a known analogue compound, 1α,6β-dihydroxy-5,10-bis-epi-eudesm-3-ene-6-O-β-D-glucopyranoside (1), were isolated from the roots of Parepigynum funingense. The structure of 2 was determined by 1D and 2D NMR spectroscopy. Compound 1 was isolated from this plant for the first time.
2007, 18(1): 76-78
doi: 10.1016/j.cclet.2006.11.002
Abstract:
Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue light after heating at 150℃ in air for 24 h, no red-shifted emission was observed by fluorescence spectroscopy.
Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue light after heating at 150℃ in air for 24 h, no red-shifted emission was observed by fluorescence spectroscopy.
2007, 18(1): 79-80
doi: 10.1016/j.cclet.2006.11.003
Abstract:
Linear copolymers from N-isopropylacrylamide (NIPA), acrylic acid (AA) and diacetone acrylamide (DAA) have been prepared.The effect of composition, ionic strength and pH on their lower critical solution temperature (LCST) has been investigated.
Linear copolymers from N-isopropylacrylamide (NIPA), acrylic acid (AA) and diacetone acrylamide (DAA) have been prepared.The effect of composition, ionic strength and pH on their lower critical solution temperature (LCST) has been investigated.
2007, 18(1): 81-84
doi: 10.1016/j.cclet.2006.11.020
Abstract:
A new heteropolytungstate,[H2bpy]3[SiMnW11O39]·1.25H2O (1), has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characterized compound containing 1D zigzag chain of transition metal substituted Keggin heteropolytungstate, which is connected through a common oxygen atom. The elemental analysis and IR of it are also described.
A new heteropolytungstate,[H2bpy]3[SiMnW11O39]·1.25H2O (1), has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characterized compound containing 1D zigzag chain of transition metal substituted Keggin heteropolytungstate, which is connected through a common oxygen atom. The elemental analysis and IR of it are also described.
2007, 18(1): 85-88
doi: 10.1016/j.cclet.2006.11.025
Abstract:
Three kinds of new layered perovskite compounds with Ruddlesden-Popper (R-P) phase, AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5), were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution. The structures of the compounds were characterized by EDX and XRD, and their antibacterial activity and light-resistance property were evaluated. The results indicated that the molecular formula of AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5) was confirmed, and that the crystalline structure of Na2La2Ti3O10 was not obviously affected by exchange of silver ion. The minimum inhibitory concentrations (MICs) of Ag0.3Na1.7La2Ti3O10 against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) were 180 μg/mL and 240 μg/mL,respectively, while its discoloration was not observed after 24 h light ageing test.
Three kinds of new layered perovskite compounds with Ruddlesden-Popper (R-P) phase, AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5), were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution. The structures of the compounds were characterized by EDX and XRD, and their antibacterial activity and light-resistance property were evaluated. The results indicated that the molecular formula of AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5) was confirmed, and that the crystalline structure of Na2La2Ti3O10 was not obviously affected by exchange of silver ion. The minimum inhibitory concentrations (MICs) of Ag0.3Na1.7La2Ti3O10 against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) were 180 μg/mL and 240 μg/mL,respectively, while its discoloration was not observed after 24 h light ageing test.
2007, 18(1): 89-90
doi: 10.1016/j.cclet.2006.11.038
Abstract:
Tris (2, 2'-bipyridine) ruthenium (Ⅱ) (Ru(bpy)32+) dichloride was successfully immobilized into the galleria of layered gamma zirconium phosphate (γ-ZrP) preintercalated by butyl amine(BA). The compounds showed extended luminescence lifetime of about four times of unimmobilized metal complex.
Tris (2, 2'-bipyridine) ruthenium (Ⅱ) (Ru(bpy)32+) dichloride was successfully immobilized into the galleria of layered gamma zirconium phosphate (γ-ZrP) preintercalated by butyl amine(BA). The compounds showed extended luminescence lifetime of about four times of unimmobilized metal complex.
2007, 18(1): 91-93
doi: 10.1016/j.cclet.2006.11.034
Abstract:
A novel method for the simultaneous determination of benserazide and levodopa using capillary electrophoresis (CE)-chemiluminescence (CL) has been developed. Under the optimal conditions, the detection limits (S/N=3) were 1.85 μg/mL for benserazide and 0.12 μg/mL for levodopa. This method was successfully applied to the determination of benserazide and levodopa in Medopar tablet, the results showed that the detected values are in accordance with those by official methods.
A novel method for the simultaneous determination of benserazide and levodopa using capillary electrophoresis (CE)-chemiluminescence (CL) has been developed. Under the optimal conditions, the detection limits (S/N=3) were 1.85 μg/mL for benserazide and 0.12 μg/mL for levodopa. This method was successfully applied to the determination of benserazide and levodopa in Medopar tablet, the results showed that the detected values are in accordance with those by official methods.
2007, 18(1): 94-96
doi: 10.1016/j.cclet.2006.11.028
Abstract:
A new method to determine the concentration of amikacin (AMK) using methyl blue (MB) as electrochemical probe was developed in this paper. In pH 4.5 Britton-Robinson (B-R) buffer solution, the MB reacted with AMK to form ion association complexes, which led to the reductive peak current of MB at -0.275 V (versus SCE) to decrease, and the decreases were linear with the concentration of AMK in the range of 1.0-60.0 mg/L, the regression of equation is AIp (nA)=-8.48+102.36c (mg/L),correlation coefficient γ is 0.997. The conditions for determining the concentration of AMK using linear sweep voltammetry (SLV) were optimized. The method was used to determine the content of amikacin commercially available with satisfactory results.
A new method to determine the concentration of amikacin (AMK) using methyl blue (MB) as electrochemical probe was developed in this paper. In pH 4.5 Britton-Robinson (B-R) buffer solution, the MB reacted with AMK to form ion association complexes, which led to the reductive peak current of MB at -0.275 V (versus SCE) to decrease, and the decreases were linear with the concentration of AMK in the range of 1.0-60.0 mg/L, the regression of equation is AIp (nA)=-8.48+102.36c (mg/L),correlation coefficient γ is 0.997. The conditions for determining the concentration of AMK using linear sweep voltammetry (SLV) were optimized. The method was used to determine the content of amikacin commercially available with satisfactory results.
2007, 18(1): 97-98
doi: 10.1016/j.cclet.2006.11.016
Abstract:
Zinc may play a role as a co-factor in the pathogenesis of Alzheimer's disease (AD) through influencing the conformation and neurotoxicity of amyloid β-protein (Aβ). Using the fluorescamine assay, we show for the first time that Zn2+induced Aβ(10-21) aggregate in a concentration-dependent manner. These results indicate that Aβ(10-21) can be used as an in vitro model in Zn2+-induced Aβ aggregation and that the region 10-21 to be the minimal fragment of zinc-binding domain of full length Aβ(1-42).
Zinc may play a role as a co-factor in the pathogenesis of Alzheimer's disease (AD) through influencing the conformation and neurotoxicity of amyloid β-protein (Aβ). Using the fluorescamine assay, we show for the first time that Zn2+induced Aβ(10-21) aggregate in a concentration-dependent manner. These results indicate that Aβ(10-21) can be used as an in vitro model in Zn2+-induced Aβ aggregation and that the region 10-21 to be the minimal fragment of zinc-binding domain of full length Aβ(1-42).
2007, 18(1): 99-102
doi: 10.1016/j.cclet.2006.11.005
Abstract:
A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO), in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6-78.3%. The relative standard deviations (R.S.D.s) for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.
A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO), in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6-78.3%. The relative standard deviations (R.S.D.s) for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.
2007, 18(1): 103-106
doi: 10.1016/j.cclet.2006.11.011
Abstract:
The oxygenation constants (Ko2) of cobalt(Ⅱ) hydroxamates (CoL21-CoL23) with benzo-15-crown-5 (B15C5) pendants were measured over the range of -5 to +20℃, and the values of thermodynamic parameters (△H0 and △S0) were calculated based on these (Ko2) values. Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110△ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidafon for p-xylene were investigated with the comparison of crown-free analogues CoL24.
The oxygenation constants (Ko2) of cobalt(Ⅱ) hydroxamates (CoL21-CoL23) with benzo-15-crown-5 (B15C5) pendants were measured over the range of -5 to +20℃, and the values of thermodynamic parameters (△H0 and △S0) were calculated based on these (Ko2) values. Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110△ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidafon for p-xylene were investigated with the comparison of crown-free analogues CoL24.
2007, 18(1): 107-110
doi: 10.1016/j.cclet.2006.11.012
Abstract:
The mechanism of Rh(Ⅱ) carbene S-H insertion into H2S in gas phase has been studied by B3LYP functional. Calculation results showed that the Rh(Ⅱ) carbene S-H insertion into H2S took only stepwise channels and no concerted channels had been located,which was different from the Rh(Ⅱ) carbene C-H and O-H insertions.
The mechanism of Rh(Ⅱ) carbene S-H insertion into H2S in gas phase has been studied by B3LYP functional. Calculation results showed that the Rh(Ⅱ) carbene S-H insertion into H2S took only stepwise channels and no concerted channels had been located,which was different from the Rh(Ⅱ) carbene C-H and O-H insertions.
2007, 18(1): 111-114
doi: 10.1016/j.cclet.2006.11.015
Abstract:
A novel maskless technique, self-driving micro-fluid porous type printing (SMPTP), was reported to in situ synthesize oligonucleotide arrays on glass slide, which has the merits of low cost, high quality and simple craft. In SMPTP for fabricating genechips, porous fiber tubes with a number of nanometric or micron channels functioned as "active letters" and were assembled in designed patterns, which are identical to the distribution of monomers in each layer of the array, and four patterns were needed for each layer. By means of capillarity, the synthesis solution was automatically taken into porous tubes assembled in a printing plate and reached the surface. An oligonucleotide array of 160 features with four different 15-mer probes was in situ synthesized using this technique. The four specific oligonucleotide probes, including the matched and the mismatched by the fluorescent target sequence, gave obviously different hybridization fluorescent signals.
A novel maskless technique, self-driving micro-fluid porous type printing (SMPTP), was reported to in situ synthesize oligonucleotide arrays on glass slide, which has the merits of low cost, high quality and simple craft. In SMPTP for fabricating genechips, porous fiber tubes with a number of nanometric or micron channels functioned as "active letters" and were assembled in designed patterns, which are identical to the distribution of monomers in each layer of the array, and four patterns were needed for each layer. By means of capillarity, the synthesis solution was automatically taken into porous tubes assembled in a printing plate and reached the surface. An oligonucleotide array of 160 features with four different 15-mer probes was in situ synthesized using this technique. The four specific oligonucleotide probes, including the matched and the mismatched by the fluorescent target sequence, gave obviously different hybridization fluorescent signals.
2007, 18(1): 115-117
doi: 10.1016/j.cclet.2006.11.010
Abstract:
Extractive electrospray ionization source (EESI) was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.
Extractive electrospray ionization source (EESI) was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.
2007, 18(1): 118-120
doi: 10.1016/j.cclet.2006.11.035
Abstract:
Crosslinked chitosan-based nanofibers were successfully prepared via electrospinning technique with heat mediated chemical crosslinking followed. The structure, morphology and mechanical property of nanofibers were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), Instron machine, respectively. The results showed that, nanofibers exhibited a smooth surface and regular morphology, and tensile strength of nanofibers improved with increasing of triethylene glycol dimethacrylate (TEGDMA) content.
Crosslinked chitosan-based nanofibers were successfully prepared via electrospinning technique with heat mediated chemical crosslinking followed. The structure, morphology and mechanical property of nanofibers were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), Instron machine, respectively. The results showed that, nanofibers exhibited a smooth surface and regular morphology, and tensile strength of nanofibers improved with increasing of triethylene glycol dimethacrylate (TEGDMA) content.
