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2010 Volume 21 Issue 2
2010, 21(2): 127-130
doi: 10.1016/j.cclet.2009.10.027
Abstract:
The new shortcut synthesis route of(±)raphidecursinol 1,a racemic 8,4'-oxyneolignan compound,can be more easily achieved by the synthesis route,starting from readily available inexpensive 3,4,5-trimethoxybenzaldehyde and 1,2,3-trihydroxybenzene.All structures were confirmed by 1H NMR.IR and MS.
The new shortcut synthesis route of(±)raphidecursinol 1,a racemic 8,4'-oxyneolignan compound,can be more easily achieved by the synthesis route,starting from readily available inexpensive 3,4,5-trimethoxybenzaldehyde and 1,2,3-trihydroxybenzene.All structures were confirmed by 1H NMR.IR and MS.
2010, 21(2): 131-134
doi: 10.1016/j.cclet.2009.10.017
Abstract:
An efficient and novel method for synthesizing 3',5'-dithio-2'-deoxyguanosine was described.In this method normal guanosine was used as the starting material.A very efficient procedure was used to synthesize 2'-O-tosyiguanosine 1,which used 0.1 eq.DBTO instead of 2 eq.1 was treated with LTBH to give 9-(2-deoxy-β-D-threo-pentofuranosyl)guanine 2.2 could be easily turned to the target compound.
An efficient and novel method for synthesizing 3',5'-dithio-2'-deoxyguanosine was described.In this method normal guanosine was used as the starting material.A very efficient procedure was used to synthesize 2'-O-tosyiguanosine 1,which used 0.1 eq.DBTO instead of 2 eq.1 was treated with LTBH to give 9-(2-deoxy-β-D-threo-pentofuranosyl)guanine 2.2 could be easily turned to the target compound.
2010, 21(2): 135-138
doi: 10.1016/j.cclet.2009.10.016
Abstract:
2,4,6-Trichloroborazine has been recognized as a desirable monomer for the preparation of high-performance boron nitride fibers through polymer derived ceramics route.So a high yield and facile synthesis of 2,4,6-trichloroborazine is essential in practice.Using boron trichloride-dimethylsulfide complex((CH3)2S·BCl3)and ammonium chloride(NH4Cl)as starting materials and toluene(C6H5CH3)as solvent,the synthesis of 2,4,6-trichloroborazine to give high yield is reported.(C)2009 Cheng Deng.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All rights reserved.
2,4,6-Trichloroborazine has been recognized as a desirable monomer for the preparation of high-performance boron nitride fibers through polymer derived ceramics route.So a high yield and facile synthesis of 2,4,6-trichloroborazine is essential in practice.Using boron trichloride-dimethylsulfide complex((CH3)2S·BCl3)and ammonium chloride(NH4Cl)as starting materials and toluene(C6H5CH3)as solvent,the synthesis of 2,4,6-trichloroborazine to give high yield is reported.(C)2009 Cheng Deng.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All rights reserved.
2010, 21(2): 139-142
doi: 10.1016/j.cclet.2009.09.007
Abstract:
A novel series of chiral dopants synthesized from(S)-1,2-propanediol and mesogenic carboxylic acids were characterized by FT-IR,1H NMR,elemental analysis and their helical twisting properties were investigated by doping the chiral dopants into a nematic liquid crystal host(SLC-1717).The results show that,the helical pitch of N*-LC mixture exhibited a terminal alkyl chain length dependence and the molecular twisting power β also exhibited a temperature dependence(increasing β with increasing temperature).
A novel series of chiral dopants synthesized from(S)-1,2-propanediol and mesogenic carboxylic acids were characterized by FT-IR,1H NMR,elemental analysis and their helical twisting properties were investigated by doping the chiral dopants into a nematic liquid crystal host(SLC-1717).The results show that,the helical pitch of N*-LC mixture exhibited a terminal alkyl chain length dependence and the molecular twisting power β also exhibited a temperature dependence(increasing β with increasing temperature).
2010, 21(2): 143-145
doi: 10.1016/j.cclet.2009.10.018
Abstract:
A novel and facile method toward a series of yellow water-borne polyurethane was developed by using an intrinsically colored diol in this paper.The yellow aqueous dispersion PCLD-HENA-PU was synthesized based on isophorone diisocyanate(IPDI),polycaprolactonediol(PCLD)and 2,2-dimethylol propionic acid(DMPA)using a yellow diol N,N-bis(2-hydroxyethyl)-4-nitroaniline(HENA)as a chain extender.Due to the complete reaction of OH group in colorant HENA with NCO group in diisocyanate,a series of stable yellow polyurethanes could be obtained conveniently and easily.The structure of PCLD-HENA-PUs was confirmed by means of Fourier transform infrared spectroscopy.The UV-visible absorption analysis showed a blue shift effect of about 7 nm when HENA was blocked into polyurethane chain.The absorption intensity of PCLD-HENA-PUs increased with increasing HENA content.It was found that the tensile strength enhanced from 8.6 to 19.6 MPa with HENA content increased from O to 18.0%,while the extensibility decreased from 449 to 300%.The thermal gravimetric analysis presented that the initial decompose temperature began from about 250℃,and had a little increase with increasing the HENA content.
A novel and facile method toward a series of yellow water-borne polyurethane was developed by using an intrinsically colored diol in this paper.The yellow aqueous dispersion PCLD-HENA-PU was synthesized based on isophorone diisocyanate(IPDI),polycaprolactonediol(PCLD)and 2,2-dimethylol propionic acid(DMPA)using a yellow diol N,N-bis(2-hydroxyethyl)-4-nitroaniline(HENA)as a chain extender.Due to the complete reaction of OH group in colorant HENA with NCO group in diisocyanate,a series of stable yellow polyurethanes could be obtained conveniently and easily.The structure of PCLD-HENA-PUs was confirmed by means of Fourier transform infrared spectroscopy.The UV-visible absorption analysis showed a blue shift effect of about 7 nm when HENA was blocked into polyurethane chain.The absorption intensity of PCLD-HENA-PUs increased with increasing HENA content.It was found that the tensile strength enhanced from 8.6 to 19.6 MPa with HENA content increased from O to 18.0%,while the extensibility decreased from 449 to 300%.The thermal gravimetric analysis presented that the initial decompose temperature began from about 250℃,and had a little increase with increasing the HENA content.
2010, 21(2): 146-150
doi: 10.1016/j.cclet.2009.10.030
Abstract:
For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2 which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness,availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.
For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2 which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness,availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.
2010, 21(2): 151-154
doi: 10.1016/j.cclet.2009.10.014
Abstract:
Anhydrous tetrabutylammonium fluoride(TBAFanh.)has been found to be a highly efficient fluorinating reagent for nucleophilic aromatic fluorinations such as fluorodenitration or halogen exchange(Halex)reaction.The products were formed in high to excellent yields under surprisingly mild reaction conditions and no phenol or ether side-products were detected in these reactions.
Anhydrous tetrabutylammonium fluoride(TBAFanh.)has been found to be a highly efficient fluorinating reagent for nucleophilic aromatic fluorinations such as fluorodenitration or halogen exchange(Halex)reaction.The products were formed in high to excellent yields under surprisingly mild reaction conditions and no phenol or ether side-products were detected in these reactions.
2010, 21(2): 155-158
doi: 10.1016/j.cclet.2009.10.004
Abstract:
All stereoisomers of asperphenamate la and patriscabratine 2a were achieved with a high yield,and total synthesis of 2a is firstly described here.The absolute configuration of patriscabratine was determined as(S,S).The compounds 1a-d and 2a-d have been tested by MTT assay in T47D,MDA-MB231,HL60,Hela and SGC-7901 cell lines in vitro.Among them,the(R,S)stereoisomer shows the strongest anticancer effects,while the(S,R)shows the weakest one.
All stereoisomers of asperphenamate la and patriscabratine 2a were achieved with a high yield,and total synthesis of 2a is firstly described here.The absolute configuration of patriscabratine was determined as(S,S).The compounds 1a-d and 2a-d have been tested by MTT assay in T47D,MDA-MB231,HL60,Hela and SGC-7901 cell lines in vitro.Among them,the(R,S)stereoisomer shows the strongest anticancer effects,while the(S,R)shows the weakest one.
2010, 21(2): 159-162
doi: 10.1016/j.cclet.2009.09.005
Abstract:
2-Benzy1-5-hydroxy-4-oxopentanoic acid 1 and its enantiomers were designed,synthesized and assayed for inhibitory activity against carboxypeptidase A(CPA,EC 3.4.17.1).To verify the role of the terminal hydroxyl group in 1 binding to CPA,2-benzyl-5benzyloxy-4-oxopentanoic acid 2 was also synthesized and evaluated.The inhibition constants show that both L-1 and D-1 were shown to have strong binding affinity with L-1 being more potent than its enantiomer by 165-fold.On the other hand,the inhibition constant of 2 increases 4-fold comparing with that of 1.In order to explore the exact binding mode of the hydroxyacteyl group of 1 to the active site zinc ion of CPA, we have solved the crystal structure of CPA complexed with L-1 up to 1.85 Å resolution. In CPA L-1 complex,the phenyl ring is fitted in the substrate recognition pocket at the S'1 subsite,and the carboxylate forms bifurcated hydrogen bonds with the guanidinium moiety of Arg-145 and Arg-127 and a hydrogen bond with the phenolic hydroxyl of the downpositioned Tyr-248.The carbonyl oxygen of L-1 does coordinate to the active site zinc ion of CPA as expectedly.Unexpectedly,the terminal hydroxyl group of L-1 is engaged in hydrogen bonding with carbonyl oxygen of Ser-197 instead of coordinating to the active site zinc ion.
2-Benzy1-5-hydroxy-4-oxopentanoic acid 1 and its enantiomers were designed,synthesized and assayed for inhibitory activity against carboxypeptidase A(CPA,EC 3.4.17.1).To verify the role of the terminal hydroxyl group in 1 binding to CPA,2-benzyl-5benzyloxy-4-oxopentanoic acid 2 was also synthesized and evaluated.The inhibition constants show that both L-1 and D-1 were shown to have strong binding affinity with L-1 being more potent than its enantiomer by 165-fold.On the other hand,the inhibition constant of 2 increases 4-fold comparing with that of 1.In order to explore the exact binding mode of the hydroxyacteyl group of 1 to the active site zinc ion of CPA, we have solved the crystal structure of CPA complexed with L-1 up to 1.85 Å resolution. In CPA L-1 complex,the phenyl ring is fitted in the substrate recognition pocket at the S'1 subsite,and the carboxylate forms bifurcated hydrogen bonds with the guanidinium moiety of Arg-145 and Arg-127 and a hydrogen bond with the phenolic hydroxyl of the downpositioned Tyr-248.The carbonyl oxygen of L-1 does coordinate to the active site zinc ion of CPA as expectedly.Unexpectedly,the terminal hydroxyl group of L-1 is engaged in hydrogen bonding with carbonyl oxygen of Ser-197 instead of coordinating to the active site zinc ion.
2010, 21(2): 163-166
doi: 10.1016/j.cclet.2009.10.013
Abstract:
A series of novel amidine derivatives of doxifluridine were synthesized using acid amide as the starting material,and their antitumor activity was evaluated in A549 cells.Compounds 10 and 11 demonstrated were more potent than 5-Fu,which was used as a positive control.Compound 10,which were found to be the most potent one with IC50 of 3.2 μmol/L,was 16 times more potent than 5-Fu with IC50 of 52 μmol/L to the A549 cells.A new route was designed to synthesize 5'-deoxy-5-fluorocytidine.All compounds were characterized by 1H NMR,MS and X-ray spectras in detail.
A series of novel amidine derivatives of doxifluridine were synthesized using acid amide as the starting material,and their antitumor activity was evaluated in A549 cells.Compounds 10 and 11 demonstrated were more potent than 5-Fu,which was used as a positive control.Compound 10,which were found to be the most potent one with IC50 of 3.2 μmol/L,was 16 times more potent than 5-Fu with IC50 of 52 μmol/L to the A549 cells.A new route was designed to synthesize 5'-deoxy-5-fluorocytidine.All compounds were characterized by 1H NMR,MS and X-ray spectras in detail.
2010, 21(2): 167-170
doi: 10.1016/j.cclet.2009.10.012
Abstract:
In this study,six thiourea derivatives of cinchona alkaloids with 9-nat or 9-epi-conflguration were synthesized.After characterized the structures,we adopted them to the asymmetric "interrupted" Feist-Bénary (IFB) reaction of α-haloketones with β-dicarbonyl compounds,to give optically active dihydrofurans.Various thiourea derivatives as organocatalysts were examined.The corresponding chiral hydroxyl dihydrofurans have been obtained in excellent yields and moderate ees.To the acyclic substrate,we obtained exciting and promising result.
In this study,six thiourea derivatives of cinchona alkaloids with 9-nat or 9-epi-conflguration were synthesized.After characterized the structures,we adopted them to the asymmetric "interrupted" Feist-Bénary (IFB) reaction of α-haloketones with β-dicarbonyl compounds,to give optically active dihydrofurans.Various thiourea derivatives as organocatalysts were examined.The corresponding chiral hydroxyl dihydrofurans have been obtained in excellent yields and moderate ees.To the acyclic substrate,we obtained exciting and promising result.
2010, 21(2): 171-174
doi: 10.1016/j.cclet.2009.10.006
Abstract:
An efficient and mild method for the direct conversion of alcohols into N-alkylphthalimides using 2,4,6-trichloro-1,3,5-triazine and dimethylformamide was described.The reaction was preceded via (alcoxymethylene) dimethylammonium chloride intermediate and produced corresponding N-alkylphthalimides in good-to-excellent yields.
An efficient and mild method for the direct conversion of alcohols into N-alkylphthalimides using 2,4,6-trichloro-1,3,5-triazine and dimethylformamide was described.The reaction was preceded via (alcoxymethylene) dimethylammonium chloride intermediate and produced corresponding N-alkylphthalimides in good-to-excellent yields.
2010, 21(2): 175-178
doi: 10.1016/j.cclet.2009.10.007
Abstract:
The addition of 2,4-dihydroxyaceto(and benzo)phenone to propiolic ester is catalyzed by triphenylphosphine or tert-butyl isocyanide to form O-vinyl aryl derivatives in fairly good yields.
The addition of 2,4-dihydroxyaceto(and benzo)phenone to propiolic ester is catalyzed by triphenylphosphine or tert-butyl isocyanide to form O-vinyl aryl derivatives in fairly good yields.
2010, 21(2): 179-182
doi: 10.1016/j.cclet.2009.10.024
Abstract:
We described a simple one-step process for the synthesis of oleic acid-capped magnetite nanoparticles using the dimethyl sulfoxide(DMSO)to oxidize the precursor Fe2+ at 140℃.By adjusting the alkalinity of the reaction system,magnetite nanoparticles with two sizes of 4 and 7 nm could be easily achieved.And the magnetite nanoparticles coated by oleate were well-monodispersed in organic solvent.
We described a simple one-step process for the synthesis of oleic acid-capped magnetite nanoparticles using the dimethyl sulfoxide(DMSO)to oxidize the precursor Fe2+ at 140℃.By adjusting the alkalinity of the reaction system,magnetite nanoparticles with two sizes of 4 and 7 nm could be easily achieved.And the magnetite nanoparticles coated by oleate were well-monodispersed in organic solvent.
2010, 21(2): 183-186
doi: 10.1016/j.cclet.2009.09.001
Abstract:
A highly efficient green protocol for the preparation of bis-indolylmethanes,bis-2-methylindolylmethanes,bis-1-methylindolylmethanes and 3,3'-diindolyloxindole derivatives from the reaction of indoles with various aldehydes and ketones in the presence of cellulose sulfuric acid under solvent-free conditions is reported.The significant features of this procedure are high yields of the products,mild reaction,solvent-free condition and non-toxicity of the catalyst.
A highly efficient green protocol for the preparation of bis-indolylmethanes,bis-2-methylindolylmethanes,bis-1-methylindolylmethanes and 3,3'-diindolyloxindole derivatives from the reaction of indoles with various aldehydes and ketones in the presence of cellulose sulfuric acid under solvent-free conditions is reported.The significant features of this procedure are high yields of the products,mild reaction,solvent-free condition and non-toxicity of the catalyst.
2010, 21(2): 187-190
doi: 10.1016/j.cclet.2009.10.023
Abstract:
The conformations of γ-butyrolactone ring in solution were deduced on the basis of 1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.
The conformations of γ-butyrolactone ring in solution were deduced on the basis of 1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.
2010, 21(2): 191-193
doi: 10.1016/j.cclet.2009.10.002
Abstract:
A new lathyrane diterpene glycoside,named 3β,7β,15β-trihydroxy-14-oxolathyra-5E,12E-dienyl-16-O-β-D-glucopyranoside,was isolated from Euphorbia helioscopia L.Its structure was established by spectroscopic techniques including 2D NMR.
A new lathyrane diterpene glycoside,named 3β,7β,15β-trihydroxy-14-oxolathyra-5E,12E-dienyl-16-O-β-D-glucopyranoside,was isolated from Euphorbia helioscopia L.Its structure was established by spectroscopic techniques including 2D NMR.
2010, 21(2): 194-196
doi: 10.1016/j.cclet.2009.09.011
Abstract:
A novel diarylheptanoid bearing flavonol moiety,named officinin A(1),along with two known compounds galangin and kaempferide were isolated from the rhizomes of Alpina officinarum Hance.The structure elucidation was accomplished by HRESI-MS,ID and 2D NMR methods.
A novel diarylheptanoid bearing flavonol moiety,named officinin A(1),along with two known compounds galangin and kaempferide were isolated from the rhizomes of Alpina officinarum Hance.The structure elucidation was accomplished by HRESI-MS,ID and 2D NMR methods.
2010, 21(2): 197-199
doi: 10.1016/j.cclet.2009.07.023
Abstract:
A new alkaloid,sinensine(1),had been isolated from the fruiting bodies of Ganoderma sinense Zhao,Xu et Zhang.Its structure was elucidated on the basis of ID and 2D spectral analysis.This alkaloid exhibited activity in protecting the injury induced by hydrogen peroxide oxidation on HUVEC,with EC50 value 6.2 μmol/L.
A new alkaloid,sinensine(1),had been isolated from the fruiting bodies of Ganoderma sinense Zhao,Xu et Zhang.Its structure was elucidated on the basis of ID and 2D spectral analysis.This alkaloid exhibited activity in protecting the injury induced by hydrogen peroxide oxidation on HUVEC,with EC50 value 6.2 μmol/L.
2010, 21(2): 200-202
doi: 10.1016/j.cclet.2009.10.029
Abstract:
One new ent-kaurane diterpenoid,named maoyecrystal L was isolated from the EtOAc extract of the dried leaves of lsodon japonica.Its structure was established by various spectroscopic means and confirmed by X-ray crystallographic analysis.
One new ent-kaurane diterpenoid,named maoyecrystal L was isolated from the EtOAc extract of the dried leaves of lsodon japonica.Its structure was established by various spectroscopic means and confirmed by X-ray crystallographic analysis.
2010, 21(2): 203-205
doi: 10.1016/j.cclet.2009.10.028
Abstract:
A new dicaffeoyl quinic acid,nannoglottisin A,has been isolated from an endemic plant of Nannoglottis ravida,and the structure of the compound was identified by means of spectroscopic analysis.
A new dicaffeoyl quinic acid,nannoglottisin A,has been isolated from an endemic plant of Nannoglottis ravida,and the structure of the compound was identified by means of spectroscopic analysis.
2010, 21(2): 206-208
doi: 10.1016/j.cclet.2009.10.005
Abstract:
A new tetrahydrophenanthrene named henryin A(1)was isolated from the leaves of Chloranthus henryi.Its structure was determined to be(S)-4,6,9-trimethyl-5,6,7,8-tetrahydrophenanthrene-1,2-diol on the basis of IR,MS,ID and 2D NMR spectral.
A new tetrahydrophenanthrene named henryin A(1)was isolated from the leaves of Chloranthus henryi.Its structure was determined to be(S)-4,6,9-trimethyl-5,6,7,8-tetrahydrophenanthrene-1,2-diol on the basis of IR,MS,ID and 2D NMR spectral.
2010, 21(2): 209-212
doi: 10.1016/j.cclet.2009.10.025
Abstract:
Chemical investigation of the pollen of Typha angustifolia Lima.has led to the isolation of two new nonacosanetriols,7,8,10-nonacosanetriol(1)and 7,9,10-nonacosanetriol(2).Their structures were elucidated by chemical reaction and spectral analysis.Compounds 1 and 2 exhibited weak activity of antiplatelet aggregation <>in vitro.
Chemical investigation of the pollen of Typha angustifolia Lima.has led to the isolation of two new nonacosanetriols,7,8,10-nonacosanetriol(1)and 7,9,10-nonacosanetriol(2).Their structures were elucidated by chemical reaction and spectral analysis.Compounds 1 and 2 exhibited weak activity of antiplatelet aggregation <>in vitro.
2010, 21(2): 213-216
doi: 10.1016/j.cclet.2009.10.031
Abstract:
High performance liquid chromatographic(HPLC)fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA)for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural network(BP-ANN),and radial basis function artificial neural network(RBF-ANN)were effectively applied to predict the category of the four different samples in the test set.
High performance liquid chromatographic(HPLC)fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA)for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural network(BP-ANN),and radial basis function artificial neural network(RBF-ANN)were effectively applied to predict the category of the four different samples in the test set.
2010, 21(2): 217-220
doi: 10.1016/j.cclet.2009.10.009
Abstract:
A high-performance capillary electrophoresis with amperometric detection(CE-AD)method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum conditions,the seven analytes could be well separated within 21 min at the separation voltage of 16 kV in a 60 mmol/Lborax running buffer(pH 8.7).A 300 μm diameter carbon disk electrode has a good response at potential of +950 mV(vs.SCE)for all analytes.Good linear relationship was established over three orders of magnitude with detection limits(S/N=3)ranged from 3.3×10-7 to 6.7×10-9 g/mL.This proposed method has been successfully applied for the determination and comparison of different batches of Rhizoma Chuanxiong samples based on their characteristic electrochemical profiles.
A high-performance capillary electrophoresis with amperometric detection(CE-AD)method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum conditions,the seven analytes could be well separated within 21 min at the separation voltage of 16 kV in a 60 mmol/Lborax running buffer(pH 8.7).A 300 μm diameter carbon disk electrode has a good response at potential of +950 mV(vs.SCE)for all analytes.Good linear relationship was established over three orders of magnitude with detection limits(S/N=3)ranged from 3.3×10-7 to 6.7×10-9 g/mL.This proposed method has been successfully applied for the determination and comparison of different batches of Rhizoma Chuanxiong samples based on their characteristic electrochemical profiles.
2010, 21(2): 221-224
doi: 10.1016/j.cclet.2009.10.019
Abstract:
Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence technique.Paraquat as an excellent quenching reagent quenched the fuorescence of Nel6 or nDs(n=1-4)driven by charge transfer.Under aggregation of nDs,α-CD did not quench the fluorescence of 1D.At lower concentration,the quenching tendency of α-CD against nDs is 2D > 3D > 4D,while at higher concentration,the tendency is 2D < 3D < 4D.α-CD showed the selective recognition on its fluorescent quenching against 1D,2D,3D and 4D.
Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence technique.Paraquat as an excellent quenching reagent quenched the fuorescence of Nel6 or nDs(n=1-4)driven by charge transfer.Under aggregation of nDs,α-CD did not quench the fluorescence of 1D.At lower concentration,the quenching tendency of α-CD against nDs is 2D > 3D > 4D,while at higher concentration,the tendency is 2D < 3D < 4D.α-CD showed the selective recognition on its fluorescent quenching against 1D,2D,3D and 4D.
2010, 21(2): 225-228
doi: 10.1016/j.cclet.2009.09.004
Abstract:
The oxidation of hydroquinone(QH2)was investigated for the first time at liquid/liquid(L/L)interface by scanning electrochemical microscopy(SECM).In this study,electron transfer(ET)from QH2 in aqueous to ferrocene(Fc)in nitrobenzene (NB)was probed.The apparent heterogeneous rate constants for ET reactions were obtained by fitting the experimental approach curves to the theoretical values.The results showed that the rate constants for oxidation reaction of QH2 were sensitive to the changes of the driving force,which increased as the driving force increased.In addition,factors that would affect ET of QH2 were studied.Experimental results indicated ion situation around QH2 molecule could change the magnitude of the rate constants because the capability of oxidation of QH2 would he affected by them.
The oxidation of hydroquinone(QH2)was investigated for the first time at liquid/liquid(L/L)interface by scanning electrochemical microscopy(SECM).In this study,electron transfer(ET)from QH2 in aqueous to ferrocene(Fc)in nitrobenzene (NB)was probed.The apparent heterogeneous rate constants for ET reactions were obtained by fitting the experimental approach curves to the theoretical values.The results showed that the rate constants for oxidation reaction of QH2 were sensitive to the changes of the driving force,which increased as the driving force increased.In addition,factors that would affect ET of QH2 were studied.Experimental results indicated ion situation around QH2 molecule could change the magnitude of the rate constants because the capability of oxidation of QH2 would he affected by them.
2010, 21(2): 229-233
doi: 10.1016/j.cclet.2009.10.001
Abstract:
Two calculation models of mass action concentrations for CaO-MgO-SiO2-Al2O3-Cr2O3 penta-slag was presented whether 3CaO·Cr2O3·3SiO2 was existence or not. Equilibrium mass action concentration of each element structure was gained. And the models results were compared with experimental activity. The final results illustrated the model without 3CaO·Cr2O3·3SiO2 was suit for reality.The model could response the element structure of slag as well.
Two calculation models of mass action concentrations for CaO-MgO-SiO2-Al2O3-Cr2O3 penta-slag was presented whether 3CaO·Cr2O3·3SiO2 was existence or not. Equilibrium mass action concentration of each element structure was gained. And the models results were compared with experimental activity. The final results illustrated the model without 3CaO·Cr2O3·3SiO2 was suit for reality.The model could response the element structure of slag as well.
2010, 21(2): 234-236
doi: 10.1016/j.cclet.2009.08.016
Abstract:
Poly(styrene-co-sodium styrene sulphonate)(P(St-NaSS))latex particles were prepared using the mixture of ethanol and water as continuous phase in the presence of surfactant by dispersion-emulsion combined polymerization.The influence of recipes on polymerization process as well as the content of sulphonate group in the purified products was investigated.Results showed that the copolymerization could be performed smoothly.When the mole ratio of NaSS/St/divinyl benzene(DVB)was 25/75/2 and the weight ratio of ethanol/water was 2/11,the product showed a low weight loss in methanol extraction purification,and the NaSS unit ratio in the purified product reached 20.6 tool%,which was close to its theoretical value of 24.9 mol%.
Poly(styrene-co-sodium styrene sulphonate)(P(St-NaSS))latex particles were prepared using the mixture of ethanol and water as continuous phase in the presence of surfactant by dispersion-emulsion combined polymerization.The influence of recipes on polymerization process as well as the content of sulphonate group in the purified products was investigated.Results showed that the copolymerization could be performed smoothly.When the mole ratio of NaSS/St/divinyl benzene(DVB)was 25/75/2 and the weight ratio of ethanol/water was 2/11,the product showed a low weight loss in methanol extraction purification,and the NaSS unit ratio in the purified product reached 20.6 tool%,which was close to its theoretical value of 24.9 mol%.
2010, 21(2): 237-241
doi: 10.1016/j.cclet.2009.10.003
Abstract:
Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene)with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by 31p NMR,1H NMR,13C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST)behavior in water and in vitro degradation property of the polymers was investigated.The results indicated that two polymers showed LCST phase transition over a range of concentrations from 0.13 to 15 wt% and pH-sensitive degradation properties.
Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene)with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by 31p NMR,1H NMR,13C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST)behavior in water and in vitro degradation property of the polymers was investigated.The results indicated that two polymers showed LCST phase transition over a range of concentrations from 0.13 to 15 wt% and pH-sensitive degradation properties.
2010, 21(2): 242-244
doi: 10.1016/j.cclet.2009.10.011
Abstract:
A novel polyamide containing xanthene structure and trifluoromethylphenoxy pendent was prepared from 9,9-bis[4-(4aminophenoxy)phenyl]xanthene,a novel diamine with 2-(4-trifluoromethylphenoxy)terephthaloyl chloride,by the low temperature polycondensation.This new polyamide with the inherent viscosity of 0.95 dL/g was amorphous and readily soluble in polar solvents such as DMAc,m-cresol,etc.This polyamide showed the glass transition temperature(Tg)of 236℃,decomposition temperature (Td)at 5% weight loss of 455℃ and char yield of 56% at 800℃ in N2.Transparent,flexible,and tough film of the polymer cast from DMAc solution exhibited tensile strength of 93 MPa,elongation at break of 14%,initial moduli of 2.2 GPa.The electric properties such as the dielectric constant of 3.03(1 MHz)and surface resistance(2.78×1014Ω),and the moisture uptake of 1.36% were also described.
A novel polyamide containing xanthene structure and trifluoromethylphenoxy pendent was prepared from 9,9-bis[4-(4aminophenoxy)phenyl]xanthene,a novel diamine with 2-(4-trifluoromethylphenoxy)terephthaloyl chloride,by the low temperature polycondensation.This new polyamide with the inherent viscosity of 0.95 dL/g was amorphous and readily soluble in polar solvents such as DMAc,m-cresol,etc.This polyamide showed the glass transition temperature(Tg)of 236℃,decomposition temperature (Td)at 5% weight loss of 455℃ and char yield of 56% at 800℃ in N2.Transparent,flexible,and tough film of the polymer cast from DMAc solution exhibited tensile strength of 93 MPa,elongation at break of 14%,initial moduli of 2.2 GPa.The electric properties such as the dielectric constant of 3.03(1 MHz)and surface resistance(2.78×1014Ω),and the moisture uptake of 1.36% were also described.
2010, 21(2): 245-248
doi: 10.1016/j.cclet.2009.09.003
Abstract:
Novel main-chain-conjugated poly(carbazol-alt-squaraine)and poly(dipyridyl-alt-squaraine)were successfully synthesized through direct polycondensation of 9-(2-ethylhexyl)carbazole-bridged or dipyridyl-bridged bispyrrole and squaric acid.The structures and properties of the polymers were characterized using 1H NMR,FT-IR,UV-vis and cyclic voltammetry.Both polymers exhibit excellent solubility in common organic solvents and good thermal stability.Their UV-vis absorption spectra indicated the polymers have broad and strong spectral responses from 200 nm to 900 nm,which reveals a low optical band gap around 1.38 eV,suggesting that they may be promising candidates for organic solar cells.
Novel main-chain-conjugated poly(carbazol-alt-squaraine)and poly(dipyridyl-alt-squaraine)were successfully synthesized through direct polycondensation of 9-(2-ethylhexyl)carbazole-bridged or dipyridyl-bridged bispyrrole and squaric acid.The structures and properties of the polymers were characterized using 1H NMR,FT-IR,UV-vis and cyclic voltammetry.Both polymers exhibit excellent solubility in common organic solvents and good thermal stability.Their UV-vis absorption spectra indicated the polymers have broad and strong spectral responses from 200 nm to 900 nm,which reveals a low optical band gap around 1.38 eV,suggesting that they may be promising candidates for organic solar cells.
2010, 21(2): 249-252
doi: 10.1016/j.cclet.2009.10.022
Abstract:
Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO)random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL)and p-dioxanone(PDO)under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP)of PCDO have been discussed.The resultant products were characterized by 1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In the presence of different CL/PDO molar feed ratios,the conversions of both monomers were kept relatively constant.DSC study suggested that with increasing the content of PDO in the copolymers,the crystalline degree of the copolymers decreased gradually.It is believed to be a promising biodegradable material.
Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO)random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL)and p-dioxanone(PDO)under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP)of PCDO have been discussed.The resultant products were characterized by 1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In the presence of different CL/PDO molar feed ratios,the conversions of both monomers were kept relatively constant.DSC study suggested that with increasing the content of PDO in the copolymers,the crystalline degree of the copolymers decreased gradually.It is believed to be a promising biodegradable material.
