Login In
2009 Volume 20 Issue 8
2009, 20(8): 889-892
doi: 10.1016/j.cclet.2009.03.050
Abstract:
Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as astrategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/ZrO2 catalyst. The result showed that, at the temperature of 210-230℃, the catalyst was shown to be capable of reducing CO in a hydrogen-rich reformate to less than 10 ppm, while keeping the CO2 conversion below 1.55% and the hydrogen consumption below 6.50%.
Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as astrategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/ZrO2 catalyst. The result showed that, at the temperature of 210-230℃, the catalyst was shown to be capable of reducing CO in a hydrogen-rich reformate to less than 10 ppm, while keeping the CO2 conversion below 1.55% and the hydrogen consumption below 6.50%.
2009, 20(8): 893-897
doi: 10.1016/j.cclet.2009.01.009
Abstract:
Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP (Dess-Martin-periodinane) reagent as an oxidant. The method was proved to be simple, convenient and the products were isolated with good yields (80-90%).
Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP (Dess-Martin-periodinane) reagent as an oxidant. The method was proved to be simple, convenient and the products were isolated with good yields (80-90%).
2009, 20(8): 898-900
doi: 10.1016/j.cclet.2009.03.032
Abstract:
A synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl) butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride. The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently, which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.
A synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl) butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride. The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently, which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.
2009, 20(8): 901-905
doi: 10.1016/j.cclet.2009.03.043
Abstract:
In order to find compounds with superior bioactivity and overcoming multidrug resistance, a novel series of 4β-N-substituted podophyllotoxin derivatives were synthesized and evaluated as potential antitumor agents. Seven novel podophyllotoxin derivatives were synthesized by linking 4β-amino-4-deoxypodophyllotoxin with alcohols through maleic acid and tested against K562 and K562/A02 using MTT assay in vitro.
In order to find compounds with superior bioactivity and overcoming multidrug resistance, a novel series of 4β-N-substituted podophyllotoxin derivatives were synthesized and evaluated as potential antitumor agents. Seven novel podophyllotoxin derivatives were synthesized by linking 4β-amino-4-deoxypodophyllotoxin with alcohols through maleic acid and tested against K562 and K562/A02 using MTT assay in vitro.
2009, 20(8): 906-908
doi: 10.1016/j.cclet.2009.03.033
Abstract:
1,5-Benzodiazepine derivatives have been synthesized by the condensation of o-phenylenediamines and ketones in the presence of boric acid as catalyst under mild conditions. This method is simple, environmentally benign and high yielding.
1,5-Benzodiazepine derivatives have been synthesized by the condensation of o-phenylenediamines and ketones in the presence of boric acid as catalyst under mild conditions. This method is simple, environmentally benign and high yielding.
2009, 20(8): 909-912
doi: 10.1016/j.cclet.2009.04.010
Abstract:
An efficient synthesis of 3,4-dihydropyrimidine 2 (1H)-ones and thiones (3,4-DHPMs) core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical Bignelli reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times.
An efficient synthesis of 3,4-dihydropyrimidine 2 (1H)-ones and thiones (3,4-DHPMs) core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical Bignelli reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times.
2009, 20(8): 913-916
doi: 10.1016/j.cclet.2009.03.047
Abstract:
A highly efficient benzylation of arenes and heteroarenes catalyzed by HfCl4/HfO2 has been developed. Broad scope of benzylation reagents have been used in this process with high yields under mild condition. Additionally, the HfO2 can be re-used after the reaction.
A highly efficient benzylation of arenes and heteroarenes catalyzed by HfCl4/HfO2 has been developed. Broad scope of benzylation reagents have been used in this process with high yields under mild condition. Additionally, the HfO2 can be re-used after the reaction.
Citrinal A, a novel tricyclic derivative of citrinin,from an algicolous fungus Penicillium sp. i-1-1
2009, 20(8): 917-920
doi: 10.1016/j.cclet.2009.03.009
Abstract:
Citrinal A (1), a novel tricyclic compound with a rare tetrahydro-2H-benzofuro[7-b][1,4]dioxin-9(3H)-one skeleton, along with two known related compounds, citrinin (2) and 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (3) were isolated from an algicolous fungus Penicillium sp. i-1-1. The structure and stereochemistry of 1 were determined by comprehensive spectral and biogenic analysis. Its cytotoxic effects on the A-549 and HL-60 cell lines were evaluated.
Citrinal A (1), a novel tricyclic compound with a rare tetrahydro-2H-benzofuro[7-b][1,4]dioxin-9(3H)-one skeleton, along with two known related compounds, citrinin (2) and 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (3) were isolated from an algicolous fungus Penicillium sp. i-1-1. The structure and stereochemistry of 1 were determined by comprehensive spectral and biogenic analysis. Its cytotoxic effects on the A-549 and HL-60 cell lines were evaluated.
2009, 20(8): 921-923
doi: 10.1016/j.cclet.2009.03.035
Abstract:
A series of novel benzimidazole derivatives was synthesized and their anti-Coxsackie virus B3(CVB3) activity was evaluated in VERO cells. Compounds 9 and 10 exhibited better inhibitory activity than those of ribavirin (RBV) with IC50 values of 5.30 and 1.06 μg/mL, respectively.
A series of novel benzimidazole derivatives was synthesized and their anti-Coxsackie virus B3(CVB3) activity was evaluated in VERO cells. Compounds 9 and 10 exhibited better inhibitory activity than those of ribavirin (RBV) with IC50 values of 5.30 and 1.06 μg/mL, respectively.
2009, 20(8): 924-926
doi: 10.1016/j.cclet.2009.03.031
Abstract:
13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect.
13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect.
2009, 20(8): 927-930
doi: 10.1016/j.cclet.2009.03.034
Abstract:
Substituted polyaryls were synthesized successfully via sterically hindered double Suzuki cross-couplings of arylboronic acids with aryl dibromides in the presence of Pd(PPh3)4 and KOtBu within a very short time.
Substituted polyaryls were synthesized successfully via sterically hindered double Suzuki cross-couplings of arylboronic acids with aryl dibromides in the presence of Pd(PPh3)4 and KOtBu within a very short time.
2009, 20(8): 931-934
doi: 10.1016/j.cclet.2009.03.015
Abstract:
A series of novel dimers of 15-membered macrolides was synthesized and evaluated. The dimers exhibited excellent activity against erythromycin-susceptible S. pneumonia, but did not show any improved activity against erythromycin-resistant S.pneumoniae encoded by erm gene.
A series of novel dimers of 15-membered macrolides was synthesized and evaluated. The dimers exhibited excellent activity against erythromycin-susceptible S. pneumonia, but did not show any improved activity against erythromycin-resistant S.pneumoniae encoded by erm gene.
2009, 20(8): 935-938
doi: 10.1016/j.cclet.2009.03.027
Abstract:
A series of 1-(1H-1,2,4-triazole-1-yl)-2-(2,4-difluorophenyl)-3-(N-isoproyl-N-substituted-amino)-2-propanols have been designed and synthesized on the basis of the active site of lanosterol 14a-demethylase (CYP51). Their structures were confirmed by MS and 1H NMR. In vitro antifungal activities of these synthesized compounds were evaluated against eight human pathogenic fungi. The results showed that all title compounds exhibited activity against fungi tested to some extent. Compounds 3c, 3d, 7a, 7b and 7c exhibited more potent antifungal activities against nearly all fungi tested except Aspergillus fumigatus than fluconazole.
A series of 1-(1H-1,2,4-triazole-1-yl)-2-(2,4-difluorophenyl)-3-(N-isoproyl-N-substituted-amino)-2-propanols have been designed and synthesized on the basis of the active site of lanosterol 14a-demethylase (CYP51). Their structures were confirmed by MS and 1H NMR. In vitro antifungal activities of these synthesized compounds were evaluated against eight human pathogenic fungi. The results showed that all title compounds exhibited activity against fungi tested to some extent. Compounds 3c, 3d, 7a, 7b and 7c exhibited more potent antifungal activities against nearly all fungi tested except Aspergillus fumigatus than fluconazole.
2009, 20(8): 939-941
doi: 10.1016/j.cclet.2009.03.046
Abstract:
A new biflavonoid, 2,3-dihydro-5,5",7,7",4'-pentahydroxy-6,6"-dimethyl-[3'-O-4''']-biflavone 1 and two known biflavonoids 2,3"-dihydroochnaflavone 2 and 2",3"-dihydro-3',3 '''-biapigenin 3 were isolated from the herb of Selaginella labordei Hieron. ex Christ. Their structures were elucidated by spectroscopic methods.
A new biflavonoid, 2,3-dihydro-5,5",7,7",4'-pentahydroxy-6,6"-dimethyl-[3'-O-4''']-biflavone 1 and two known biflavonoids 2,3"-dihydroochnaflavone 2 and 2",3"-dihydro-3',3 '''-biapigenin 3 were isolated from the herb of Selaginella labordei Hieron. ex Christ. Their structures were elucidated by spectroscopic methods.
2009, 20(8): 942-944
doi: 10.1016/j.cclet.2009.03.039
Abstract:
A new isoflavone was obstained from the medicinal herb Amorpha fruticosa. It was elucidated asbenzopyran-12-one,1,4,10,11-tetrahydro-6'-[8'-(hydroxymethyl)ethenyl]-2,3-dimethoxy-8'-O-β-D-glucopyranosyl-O-α-D-arabinoside by spectroscopic methods including UV, IR, 1D NMR and 2D NMR techniques. And the activity against acetaminophen-induced hepatotoxicity of this compound was also studied, and found this compound can protect liver obviously from hepatotoxicity induced by acetaminophen (AAP).
A new isoflavone was obstained from the medicinal herb Amorpha fruticosa. It was elucidated asbenzopyran-12-one,1,4,10,11-tetrahydro-6'-[8'-(hydroxymethyl)ethenyl]-2,3-dimethoxy-8'-O-β-D-glucopyranosyl-O-α-D-arabinoside by spectroscopic methods including UV, IR, 1D NMR and 2D NMR techniques. And the activity against acetaminophen-induced hepatotoxicity of this compound was also studied, and found this compound can protect liver obviously from hepatotoxicity induced by acetaminophen (AAP).
2009, 20(8): 945-948
doi: 10.1016/j.cclet.2009.03.029
Abstract:
Two novel 4,5-secoeudesmane sesquiterpenoids, oxyphyllones A (1) and B (2) were isolated from the fruits of Alpinia oxyphylla. Their structures were established by spectroscopic methods including 1D and 2D NMR spectra. These two compounds are the first example of naturally occurring sesquiterpenoids with a 4,5-secoeudesmane skeleton in the family of Zingiberaceae and oxyphyllone A (1) is the first 4,5-secoeudesmane type of 13-norsesquiterpenoid. Compounds 1 and 2 exhibited no cytotoxicities against three cancer cell lines at 10 μg/mL.
Two novel 4,5-secoeudesmane sesquiterpenoids, oxyphyllones A (1) and B (2) were isolated from the fruits of Alpinia oxyphylla. Their structures were established by spectroscopic methods including 1D and 2D NMR spectra. These two compounds are the first example of naturally occurring sesquiterpenoids with a 4,5-secoeudesmane skeleton in the family of Zingiberaceae and oxyphyllone A (1) is the first 4,5-secoeudesmane type of 13-norsesquiterpenoid. Compounds 1 and 2 exhibited no cytotoxicities against three cancer cell lines at 10 μg/mL.
2009, 20(8): 949-951
doi: 10.1016/j.cclet.2009.04.009
Abstract:
A new eremophilane-type sesquiterpene, 1α,8β,10β-trihydroxy-6β-(2-methylacryloyl)oxyeremophil-7(11)-en-8α,12-olide,was isolated from the roots of Ligularia virgaurea. Its structure was established on the basis of various spectroscopic analyses,including the 1D, 2D NMR techniques and HR-ESI-MS.
A new eremophilane-type sesquiterpene, 1α,8β,10β-trihydroxy-6β-(2-methylacryloyl)oxyeremophil-7(11)-en-8α,12-olide,was isolated from the roots of Ligularia virgaurea. Its structure was established on the basis of various spectroscopic analyses,including the 1D, 2D NMR techniques and HR-ESI-MS.
2009, 20(8): 952-954
doi: 10.1016/j.cclet.2009.03.041
Abstract:
Three new sesquiterpenes, namely schensianol A (1), schensianolside A (2) and schensianolside B (3) were isolated from the stems and leaves of Euonymus schensianus Maxim. Their structures were established by chemical methods and spectroscopic techniques including 2D NMR.
Three new sesquiterpenes, namely schensianol A (1), schensianolside A (2) and schensianolside B (3) were isolated from the stems and leaves of Euonymus schensianus Maxim. Their structures were established by chemical methods and spectroscopic techniques including 2D NMR.
2009, 20(8): 955-957
doi: 10.1016/j.cclet.2009.03.045
Abstract:
A new protoberberine alkaloid, named 5,6-dihydro-10-hydroxy-2,3,9-trimethoxy-13-methyldibenzo[a,g]quinolizinium (1) was isolated from the 60% ethanol extract of the tubers of Corydalis yanhusuo W. T. Wang, together with a new natural product, 13-methylpalmatrubine (2). Their structures were established by spectroscopic methods.
A new protoberberine alkaloid, named 5,6-dihydro-10-hydroxy-2,3,9-trimethoxy-13-methyldibenzo[a,g]quinolizinium (1) was isolated from the 60% ethanol extract of the tubers of Corydalis yanhusuo W. T. Wang, together with a new natural product, 13-methylpalmatrubine (2). Their structures were established by spectroscopic methods.
2009, 20(8): 958-960
doi: 10.1016/j.cclet.2009.03.040
Abstract:
A new phenolic lactone, named phellolactone (1) was isolated from the bark of Phellodendron chinense Schneid and its structure was elucidated by means of extensively spectroscopic methods, including IR, UV, HRESI-MS and NMR techniques.
A new phenolic lactone, named phellolactone (1) was isolated from the bark of Phellodendron chinense Schneid and its structure was elucidated by means of extensively spectroscopic methods, including IR, UV, HRESI-MS and NMR techniques.
2009, 20(8): 961-964
doi: 10.1016/j.cclet.2009.01.038
Abstract:
New unsymmetrical diamine monomer containing triaryl imidazole pendent group, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)phenoxy]-1,3-benzenediamine, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(4,5-diphenyl-1H-imidazol-2-yl)phenol, followed by palladium-catalyzed hydrazine reduction. This new monomer was further confirmed by FT-IR,1H NMR and 13C NMR. Novel polyamides having pendant triaryl imidazole group were prepared by the phosphorylation polycondensation of four commercially aromatic dicarboxylic acids with the prepared diamine. Inherent viscosities of polyamides were in the range 0.42-0.53 dL/g indicating formation of medium molecular weight polymers.Polyamides exhibited glass-transition temperature (Tg) in the range 236-265℃. These polymers are essentially amorphous and were soluble in polar aprotic solvents such as DMF, NMP, DMAc. The 10% weight loss temperatures in air atmosphere, measured by TGA were in the range 350-373℃ indicating their good thermal stabilities.
New unsymmetrical diamine monomer containing triaryl imidazole pendent group, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)phenoxy]-1,3-benzenediamine, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(4,5-diphenyl-1H-imidazol-2-yl)phenol, followed by palladium-catalyzed hydrazine reduction. This new monomer was further confirmed by FT-IR,1H NMR and 13C NMR. Novel polyamides having pendant triaryl imidazole group were prepared by the phosphorylation polycondensation of four commercially aromatic dicarboxylic acids with the prepared diamine. Inherent viscosities of polyamides were in the range 0.42-0.53 dL/g indicating formation of medium molecular weight polymers.Polyamides exhibited glass-transition temperature (Tg) in the range 236-265℃. These polymers are essentially amorphous and were soluble in polar aprotic solvents such as DMF, NMP, DMAc. The 10% weight loss temperatures in air atmosphere, measured by TGA were in the range 350-373℃ indicating their good thermal stabilities.
2009, 20(8): 965-968
doi: 10.1016/j.cclet.2009.02.019
Abstract:
Two poly(aryl ether)s containing naphthyl moieties were prepared from bis(3,5-dimethyl-4-hydroxyphenyl)naphthyl methane (monomer 1) via nucleophilic aromatic substitution polycondensation with bis(4-fluorophenyl) ketone and bis(4-fluorophenyl) sulfone. The structures of these polymers were confirmed by 1H NMR. The Mn values of the two polymers were 96,200 and 88,600,respectively. The polymers exhibited good thermal stabilities with 5% mass loss at T>400℃ and high glass-transition temperature (Tg) of T>250℃. Moreover, the resultant polymers were amorphous determined by wide angle X-ray diffraction (WAXD).
Two poly(aryl ether)s containing naphthyl moieties were prepared from bis(3,5-dimethyl-4-hydroxyphenyl)naphthyl methane (monomer 1) via nucleophilic aromatic substitution polycondensation with bis(4-fluorophenyl) ketone and bis(4-fluorophenyl) sulfone. The structures of these polymers were confirmed by 1H NMR. The Mn values of the two polymers were 96,200 and 88,600,respectively. The polymers exhibited good thermal stabilities with 5% mass loss at T>400℃ and high glass-transition temperature (Tg) of T>250℃. Moreover, the resultant polymers were amorphous determined by wide angle X-ray diffraction (WAXD).
2009, 20(8): 969-972
doi: 10.1016/j.cclet.2009.03.038
Abstract:
This paper describes the formation of magnetic and fluorescent nanocomposite particles which consist of superparamagneticFe3O4core, SiO2 shell and organic dye (FITC) coating layer on their surface. The obtained nanocomposites possess typical superparamagnetism and exhibit clear green fluorescence image. And their fluorescence emission is pH-dependent, which would be applied to pH sensing.
This paper describes the formation of magnetic and fluorescent nanocomposite particles which consist of superparamagneticFe3O4core, SiO2 shell and organic dye (FITC) coating layer on their surface. The obtained nanocomposites possess typical superparamagnetism and exhibit clear green fluorescence image. And their fluorescence emission is pH-dependent, which would be applied to pH sensing.
2009, 20(8): 973-976
doi: 10.1016/j.cclet.2009.03.025
Abstract:
Ethoxymethxoymethane (EMM) was conveniently prepared by acetalization of aqueous formaldehyde with methanol and ethanol in a batch reactive distillation mode using a cation-exchange resin catalyst for the first time. EMM was found to be a significant cosolvent of methanol/gasoline blends.
Ethoxymethxoymethane (EMM) was conveniently prepared by acetalization of aqueous formaldehyde with methanol and ethanol in a batch reactive distillation mode using a cation-exchange resin catalyst for the first time. EMM was found to be a significant cosolvent of methanol/gasoline blends.
2009, 20(8): 977-980
doi: 10.1016/j.cclet.2009.03.036
Abstract:
Highly luminescent water-soluble CdTe quantum dots (QDs) have been synthesized with an electrogenerated precursor. The obtained CdTe QDs can possess good crystallizability, high quantum yield (QY) and favorable stability. Furthermore, a detection system is designed firstly for the investigation of the temperature-dependent PL of the QDs.
Highly luminescent water-soluble CdTe quantum dots (QDs) have been synthesized with an electrogenerated precursor. The obtained CdTe QDs can possess good crystallizability, high quantum yield (QY) and favorable stability. Furthermore, a detection system is designed firstly for the investigation of the temperature-dependent PL of the QDs.
2009, 20(8): 981-984
doi: 10.1016/j.cclet.2009.03.018
Abstract:
The electrochemical properties of two basic violets (methyl violet and ethyl violet) at the MWNTs/Nafion modified glassy carbon electrode were investigated. The redox of the basic violets is two-electron and two-proton process, and methyl violet presents stronger electron transfer capacity than ethyl violet. Meanwhile, the inclusion constants of the two basic violets with five CDs were determined by differential pulse voltammetry (DPV). The two basic violets and CDs can form 1:1 complexes.The inclusion capacities of the two basic violets follow the same order:CM-β-CD > HP-β-CD > TM-β-CD > DM-β-CD > β-CD.
The electrochemical properties of two basic violets (methyl violet and ethyl violet) at the MWNTs/Nafion modified glassy carbon electrode were investigated. The redox of the basic violets is two-electron and two-proton process, and methyl violet presents stronger electron transfer capacity than ethyl violet. Meanwhile, the inclusion constants of the two basic violets with five CDs were determined by differential pulse voltammetry (DPV). The two basic violets and CDs can form 1:1 complexes.The inclusion capacities of the two basic violets follow the same order:CM-β-CD > HP-β-CD > TM-β-CD > DM-β-CD > β-CD.
2009, 20(8): 985-989
doi: 10.1016/j.cclet.2009.03.020
Abstract:
The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the synthesis of a new attapulgitesupported polymer for selective separation of Ce(Ⅲ) from aqueous solution. The imprinting mechanism of prepared ion-imprinted polymer were discussed with the Characteristics of FT-IR and SEM. Results from the experiments of adsorption capacity and selectivity suggested that ion-imprinted polymer offered a fast kinetics for the adsorption of Ce(Ⅲ) under the optimum conditions.Its maximum adsorption capacity was 38.02 mg/g, and the selective recognition towards Ce(Ⅲ) was much higher than that of the non-imprinted polymer and attapulgite. The prepared functional polymer was shown to be promising for selective separation and enrichment of trace Ce(Ⅲ) in environmental samples.
The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the synthesis of a new attapulgitesupported polymer for selective separation of Ce(Ⅲ) from aqueous solution. The imprinting mechanism of prepared ion-imprinted polymer were discussed with the Characteristics of FT-IR and SEM. Results from the experiments of adsorption capacity and selectivity suggested that ion-imprinted polymer offered a fast kinetics for the adsorption of Ce(Ⅲ) under the optimum conditions.Its maximum adsorption capacity was 38.02 mg/g, and the selective recognition towards Ce(Ⅲ) was much higher than that of the non-imprinted polymer and attapulgite. The prepared functional polymer was shown to be promising for selective separation and enrichment of trace Ce(Ⅲ) in environmental samples.
2009, 20(8): 990-994
doi: 10.1016/j.cclet.2009.03.028
Abstract:
Detection of deoxyribozyme (DNAzyme) cleavage process usually needs complex and time-consuming radial labeling, gel electrophoresis and autoradiography. This paper reported an approach to detect DNAzyme cleavage process in real time using a fluorescence probe. The probe was employed as DNAzyme substrate to convert directly the cleavage information into fluorescence signal in real time. Compared with traditional approach, this non-isotope method not only brought a convenient means to monitor the DNAzyme cleavage reaction, but also offered abundant dynamic data for choosing potential gene therapeutic agents. It provides a new tool for DNAzyme research, as well as a new insight into research on human disease diagnosis. Based on this method, 8-17deoxyribozyme (8-17DNAzyme) against hepatitis C virus RNA (HCV-RNA) was designed and the cleavage process was studied in real time.
Detection of deoxyribozyme (DNAzyme) cleavage process usually needs complex and time-consuming radial labeling, gel electrophoresis and autoradiography. This paper reported an approach to detect DNAzyme cleavage process in real time using a fluorescence probe. The probe was employed as DNAzyme substrate to convert directly the cleavage information into fluorescence signal in real time. Compared with traditional approach, this non-isotope method not only brought a convenient means to monitor the DNAzyme cleavage reaction, but also offered abundant dynamic data for choosing potential gene therapeutic agents. It provides a new tool for DNAzyme research, as well as a new insight into research on human disease diagnosis. Based on this method, 8-17deoxyribozyme (8-17DNAzyme) against hepatitis C virus RNA (HCV-RNA) was designed and the cleavage process was studied in real time.
2009, 20(8): 995-999
doi: 10.1016/j.cclet.2009.03.037
Abstract:
The hydrophobic surface modification of chitosan gels was carried out using the amidating reaction of amido groups on a gel surface with stearic acid activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Lipases from Candida rugosa were adsorbed on the nascent chitosan gels (CS) and stearyl-modified gels (SCS)with different degrees of amidation. The increased surface hydrophobicity of chitosan gels improved the adsorption capacity and activity of the immobilized lipase. SCS with 31.46% amidation showed the maximum activity retention (83.43%). The experimental results suggest that the moderate surface hydrophilicity/hydrophobicity of chitosan gels is necessary for the improvement of the activity of immobilized lipase.
The hydrophobic surface modification of chitosan gels was carried out using the amidating reaction of amido groups on a gel surface with stearic acid activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Lipases from Candida rugosa were adsorbed on the nascent chitosan gels (CS) and stearyl-modified gels (SCS)with different degrees of amidation. The increased surface hydrophobicity of chitosan gels improved the adsorption capacity and activity of the immobilized lipase. SCS with 31.46% amidation showed the maximum activity retention (83.43%). The experimental results suggest that the moderate surface hydrophilicity/hydrophobicity of chitosan gels is necessary for the improvement of the activity of immobilized lipase.
2009, 20(8): 1000-1004
doi: 10.1016/j.cclet.2009.03.051
Abstract:
A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700℃ in 12 min. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction.
A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700℃ in 12 min. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction.
2009, 20(8): 1005-1009
doi: 10.1016/j.cclet.2009.03.021
Abstract:
A kinetic study of the electron-transfer in the reaction of tribenzylchlorotin with potassium 12-tungsto cobalt (Ⅲ) ate ion,K5[CoW12O40], abbreviated as Co(Ⅲ)W, has been performed in different solvents. The studies were carried out in methanol,ethanol, acetonitrile and acetic acid/water. The rate constants, reaction rates and activation parameters were calculated.
Our findings show that the rate of disappearance of the Co(Ⅲ) is pseudo-first order. The kinetic data is strongly affected by used solvents. The maximum and minimum rate constants were achieved in the ethanol and acetic acid/water (70/30) as a solvent, respectively. In all of the used solvents, negative value of activation entropies was observed, but negative activation enthalpies are observed in methanol, ethanol and acetonitrile. The reaction rate is increased with increase of Co(Ⅲ) concentration.
A kinetic study of the electron-transfer in the reaction of tribenzylchlorotin with potassium 12-tungsto cobalt (Ⅲ) ate ion,K5[CoW12O40], abbreviated as Co(Ⅲ)W, has been performed in different solvents. The studies were carried out in methanol,ethanol, acetonitrile and acetic acid/water. The rate constants, reaction rates and activation parameters were calculated.
Our findings show that the rate of disappearance of the Co(Ⅲ) is pseudo-first order. The kinetic data is strongly affected by used solvents. The maximum and minimum rate constants were achieved in the ethanol and acetic acid/water (70/30) as a solvent, respectively. In all of the used solvents, negative value of activation entropies was observed, but negative activation enthalpies are observed in methanol, ethanol and acetonitrile. The reaction rate is increased with increase of Co(Ⅲ) concentration.
2009, 20(8): 1010-1014
doi: 10.1016/j.cclet.2009.03.007
Abstract:
The reaction of Os+(6D,4F) with N2O has been investigated at B3LYP/TZVP and CCSD(T)/6-311+G* levels of theory. The mechanisms corresponding to O-atom and N-atom transfer reactions have been revealed. It was found that on the sextet reactionsurface both the O-atom and N-atom transfer reactions undergo through direct-abstraction mechanism, leading to the formation of OsO+ and OsN+, whereas on quartet surface the wo reactions undergo through O-N bond or N-N bond insertion mechanism. The calculated energetics shows that the reactions on the sextet surface have notable energy barriers, whereas the reactions on quartet surface are barrierless.
The reaction of Os+(6D,4F) with N2O has been investigated at B3LYP/TZVP and CCSD(T)/6-311+G* levels of theory. The mechanisms corresponding to O-atom and N-atom transfer reactions have been revealed. It was found that on the sextet reactionsurface both the O-atom and N-atom transfer reactions undergo through direct-abstraction mechanism, leading to the formation of OsO+ and OsN+, whereas on quartet surface the wo reactions undergo through O-N bond or N-N bond insertion mechanism. The calculated energetics shows that the reactions on the sextet surface have notable energy barriers, whereas the reactions on quartet surface are barrierless.
