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2008 Volume 19 Issue 10
2008, 19(10): 1139-1142
doi: 10.1016/j.cclet.2008.07.009
Abstract:
A novel method for the synthesis of N-monosubstituted aniline and its derivatives via β-cyclodextrin(CD)host-guest complexes has been presented.The mild reaction gives the title compounds with high selectivity in good yields of 90-98%.
A novel method for the synthesis of N-monosubstituted aniline and its derivatives via β-cyclodextrin(CD)host-guest complexes has been presented.The mild reaction gives the title compounds with high selectivity in good yields of 90-98%.
2008, 19(10): 1143-1146
doi: 10.1016/j.cclet.2008.06.050
Abstract:
A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here.The reaction is efficiently catalyzed by silicasupported sulfuric acid as it provided the title compounds in high yields and relatively short times.The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reactions.
A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here.The reaction is efficiently catalyzed by silicasupported sulfuric acid as it provided the title compounds in high yields and relatively short times.The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reactions.
2008, 19(10): 1147-1150
doi: 10.1016/j.cclet.2008.06.030
Abstract:
1-(1-Adamantylamino)-2,4,6-trinitrobenzene (1) as a potential energy material has been synthesized in excellent yield and characterized by FT-IR,1H NMR and single crystallographic methods,and is thermally stable,decomposed in the range of 215-72℃.
1-(1-Adamantylamino)-2,4,6-trinitrobenzene (1) as a potential energy material has been synthesized in excellent yield and characterized by FT-IR,1H NMR and single crystallographic methods,and is thermally stable,decomposed in the range of 215-72℃.
2008, 19(10): 1151-1155
doi: 10.1016/j.cclet.2008.07.026
Abstract:
A simple and efficient procedure for the preparation of aryl-14-H-dibenzo[a,j]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes,in the presence of silica supported sodium hydrogen sulfate(NaHSO4/SiO2)as a catalyst and in the absence of solvent has been developed.The present method offers several advantages such as excellent yields,short reaction time (10-30 min),mild condition,simple work-up,and the Use of a cheap and environmentally friendly catalyst with remarkable reusability.
A simple and efficient procedure for the preparation of aryl-14-H-dibenzo[a,j]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes,in the presence of silica supported sodium hydrogen sulfate(NaHSO4/SiO2)as a catalyst and in the absence of solvent has been developed.The present method offers several advantages such as excellent yields,short reaction time (10-30 min),mild condition,simple work-up,and the Use of a cheap and environmentally friendly catalyst with remarkable reusability.
2008, 19(10): 1156-1158
doi: 10.1016/j.cclet.2008.07.011
Abstract:
Direct electrochemical reduction of p-nitrophenol(PNP)was investigated on a room temperature ionic liquid N-butylpyridinium hexafluorophosphate(BPPF6)modified carbon paste electrode(CILE).The cathodic peak potential was positively shifted and the peak currents were increased compared to that obtained on traditional carbon paste electrode(CPE).The results indicated that the presence of ionic liquid BPPF6 on the electrode surface showed excellent catalytic ability to the electrochemical reduction of PNP.The electrochemical behaviors of PNP on the CILE were investigated by cyclic voltammetry and the conditions such as the scan rate,the buffer pH,the substrate concentration were optimized.The electrochemical parameters were further calculated with the results of the electron transfer number(n),the charge-transfer coefficient(α) and the surface concentration(ΓΥ)as 1.76,0.37 and 2.47×10-9 mol/cm2,respectively,for the selected reducfive peak.The results indicated that PNP showed all irreversible adsorption-controlled electrode process on the CILE.
Direct electrochemical reduction of p-nitrophenol(PNP)was investigated on a room temperature ionic liquid N-butylpyridinium hexafluorophosphate(BPPF6)modified carbon paste electrode(CILE).The cathodic peak potential was positively shifted and the peak currents were increased compared to that obtained on traditional carbon paste electrode(CPE).The results indicated that the presence of ionic liquid BPPF6 on the electrode surface showed excellent catalytic ability to the electrochemical reduction of PNP.The electrochemical behaviors of PNP on the CILE were investigated by cyclic voltammetry and the conditions such as the scan rate,the buffer pH,the substrate concentration were optimized.The electrochemical parameters were further calculated with the results of the electron transfer number(n),the charge-transfer coefficient(α) and the surface concentration(ΓΥ)as 1.76,0.37 and 2.47×10-9 mol/cm2,respectively,for the selected reducfive peak.The results indicated that PNP showed all irreversible adsorption-controlled electrode process on the CILE.
2008, 19(10): 1159-1162
doi: 10.1016/j.cclet.2008.06.035
Abstract:
Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas) and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.
Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas) and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.
2008, 19(10): 1163-1166
doi: 10.1016/j.cclet.2008.06.052
Abstract:
A new series of compounds (E)-1-(4-(bis-arylmethyl)piperazin-l-y1)-3-arylprop-2-en-1-one(1a-r),have been synthesized and their structures were confirmed by ESI-MS and 1H NMR.The preliminary pharmacological screening showed that some of these compounds had similar neuroprotective effects with Edaravone.
A new series of compounds (E)-1-(4-(bis-arylmethyl)piperazin-l-y1)-3-arylprop-2-en-1-one(1a-r),have been synthesized and their structures were confirmed by ESI-MS and 1H NMR.The preliminary pharmacological screening showed that some of these compounds had similar neuroprotective effects with Edaravone.
2008, 19(10): 1167-1170
doi: 10.1016/j.cclet.2008.06.043
Abstract:
Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen,nitro,and cyano groups.
Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen,nitro,and cyano groups.
2008, 19(10): 1171-1174
doi: 10.1016/j.cclet.2008.06.048
Abstract:
An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes,2-naphthol and urea or amides,in the presence of HClO4-SiO2 as a heterogeneous catalyst.The reactions were carried out under reflux and solvent-free conditions.The present methodology offers several advantages such as excellent yields,simple procedure,easy work-up and ecofriendly reaction condition.The catalystis easily prepared,stable,reusable and efficient under the reaction conditions.
An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes,2-naphthol and urea or amides,in the presence of HClO4-SiO2 as a heterogeneous catalyst.The reactions were carried out under reflux and solvent-free conditions.The present methodology offers several advantages such as excellent yields,simple procedure,easy work-up and ecofriendly reaction condition.The catalystis easily prepared,stable,reusable and efficient under the reaction conditions.
2008, 19(10): 1175-1178
doi: 10.1016/j.cclet.2008.07.005
Abstract:
Effects of Lewis acid BF3·OEt2,and Brønsted acids TsOH,CF3COOH,H3PO4,and HClO4 as cocatalyst respectively on the ligand-free palladium-catalyzed amidocarbonylation were investigated.SO3H-functional ionic liquids 1-methyl-3-(4-sulfonic acid)butylimidazolium hydrosulfate[MIm(CH2)4SO3H][HSO4]and 1-methyl-3-(4-sulfonic acid)butyrlimidazolium triflate [MIm(CH2)4SO3H][OTf]were firstly employed as cocatalysts instead of these Lewis acid and Brønsted acids.By using a ligand-free and weak corrosive catalyst in situ prepared form PdBr2,LiBr·H2O,and[MIm(CH2)4SO3H][OTq,the amidocarbonylation of benzaldehyde,acetamide,and CO could proceed smoothly and afford N-acetyl-α-phenylglycine with yield of 58% in [C6mim]PF6 medium.
Effects of Lewis acid BF3·OEt2,and Brønsted acids TsOH,CF3COOH,H3PO4,and HClO4 as cocatalyst respectively on the ligand-free palladium-catalyzed amidocarbonylation were investigated.SO3H-functional ionic liquids 1-methyl-3-(4-sulfonic acid)butylimidazolium hydrosulfate[MIm(CH2)4SO3H][HSO4]and 1-methyl-3-(4-sulfonic acid)butyrlimidazolium triflate [MIm(CH2)4SO3H][OTf]were firstly employed as cocatalysts instead of these Lewis acid and Brønsted acids.By using a ligand-free and weak corrosive catalyst in situ prepared form PdBr2,LiBr·H2O,and[MIm(CH2)4SO3H][OTq,the amidocarbonylation of benzaldehyde,acetamide,and CO could proceed smoothly and afford N-acetyl-α-phenylglycine with yield of 58% in [C6mim]PF6 medium.
2008, 19(10): 1179-1182
doi: 10.1016/j.cclet.2008.06.037
Abstract:
Regio- and enantioselective reduction of substituted acenaphthenequinones were conducted under mild reaction conditions using plant enzymatic systems.A screening of 15 plants allowed the selection of two suitable plants fulfilling enantiocomplementarity.The (+)-and(-)-mono hydroxyacenaphthenones were achieved with high conversion and good enantiomeric purity using peach(Prunus persica(L.)Batseh.,conversion 98%,71% ee)and carrot(Daucus carota L.,conversion 95%,81% ee),respectively.
Regio- and enantioselective reduction of substituted acenaphthenequinones were conducted under mild reaction conditions using plant enzymatic systems.A screening of 15 plants allowed the selection of two suitable plants fulfilling enantiocomplementarity.The (+)-and(-)-mono hydroxyacenaphthenones were achieved with high conversion and good enantiomeric purity using peach(Prunus persica(L.)Batseh.,conversion 98%,71% ee)and carrot(Daucus carota L.,conversion 95%,81% ee),respectively.
2008, 19(10): 1183-1185
doi: 10.1016/j.cclet.2008.06.039
Abstract:
Fifteen dihydropyrimidinthiones have been synthesized by microwave-assisted Biginelli reactions without any solvent of catalyst.The advantages of this novel protocol include the excellent yield,operational simplicity,short time and the avoidance of the use of organic solvents and catalysts.
Fifteen dihydropyrimidinthiones have been synthesized by microwave-assisted Biginelli reactions without any solvent of catalyst.The advantages of this novel protocol include the excellent yield,operational simplicity,short time and the avoidance of the use of organic solvents and catalysts.
2008, 19(10): 1186-1189
doi: 10.1016/j.cclet.2008.07.015
Abstract:
A simple,efficient,and environment benign route was developed for the preparation of bis-(indolyl)methanes and 14-aryl-14H-dibenzo[a,j]xanthenes from condensation of various aromatic aldehydes or ketones with indole,and 2-naphthol,respectively,using oxalic acid catalyst in aqueous medium.Use of cheap and easily available catalyst,better yields and simple reaction protocol are the advantages of the present method.
A simple,efficient,and environment benign route was developed for the preparation of bis-(indolyl)methanes and 14-aryl-14H-dibenzo[a,j]xanthenes from condensation of various aromatic aldehydes or ketones with indole,and 2-naphthol,respectively,using oxalic acid catalyst in aqueous medium.Use of cheap and easily available catalyst,better yields and simple reaction protocol are the advantages of the present method.
2008, 19(10): 1190-1192
doi: 10.1016/j.cclet.2008.07.004
Abstract:
The photochemical reaction of magnesium tetraphenyl porphyrin(MgTPP) with O2 was studied in CH2Cl2 by steady-state fluorescence,UV-vis absorption,FTlR and MALDI-TOF MS measurements.These spectra indicate that O2 can react with Mg TPP excited by irradiation.forming the stable 1:1 coordinated adduct of MgTPP-O2.In the adduct,the oxygen atoms of O2 may insert in the Mg-N bonds in MgTPP and birid with the nitrogen atoms of MgTPP to form N-O-Mg bonds.
The photochemical reaction of magnesium tetraphenyl porphyrin(MgTPP) with O2 was studied in CH2Cl2 by steady-state fluorescence,UV-vis absorption,FTlR and MALDI-TOF MS measurements.These spectra indicate that O2 can react with Mg TPP excited by irradiation.forming the stable 1:1 coordinated adduct of MgTPP-O2.In the adduct,the oxygen atoms of O2 may insert in the Mg-N bonds in MgTPP and birid with the nitrogen atoms of MgTPP to form N-O-Mg bonds.
2008, 19(10): 1193-1195
doi: 10.1016/j.cclet.2008.06.042
Abstract:
Two series of 1-(benzoxazole-2-yl) piperazine(8a-i) and 4-(benzoxazole-2-yl) piperidine compounds(10a-i) were designed,synthesized and evaluated for their α1-AR antagonistic activities.Biological assay in vitro indicated that 10h showed slightly stronger α1-AR antagonistic activity to that of our lead compound 1.
Two series of 1-(benzoxazole-2-yl) piperazine(8a-i) and 4-(benzoxazole-2-yl) piperidine compounds(10a-i) were designed,synthesized and evaluated for their α1-AR antagonistic activities.Biological assay in vitro indicated that 10h showed slightly stronger α1-AR antagonistic activity to that of our lead compound 1.
2008, 19(10): 1196-1198
doi: 10.1016/j.cclet.2008.06.047
Abstract:
α-{3-[2-hydroxy-3-(N-methyl-N-hydroxyethylamino)propoxy]propyl}-ω-butylpolydimethylsiloxanes Ⅲ with various moleculax weights were prepared by epoxy addition of α-[3-(2,3-epoxy-propoxy)propyl]-ω-butylpolydimethylsiloxanes Ⅱ and N-methylmonoethanolamine.At each step.the outcome compounds were characterized through FT-IR and NMR spectra,the results showed that each step was successfully carried out and objective products were achieved.
α-{3-[2-hydroxy-3-(N-methyl-N-hydroxyethylamino)propoxy]propyl}-ω-butylpolydimethylsiloxanes Ⅲ with various moleculax weights were prepared by epoxy addition of α-[3-(2,3-epoxy-propoxy)propyl]-ω-butylpolydimethylsiloxanes Ⅱ and N-methylmonoethanolamine.At each step.the outcome compounds were characterized through FT-IR and NMR spectra,the results showed that each step was successfully carried out and objective products were achieved.
2008, 19(10): 1199-1201
doi: 10.1016/j.cclet.2008.06.055
Abstract:
Three novel calix[6]phyrin derivatives have been synthesized by reaction of corresponding tripyrrane with aromatic aldehyde.The reaction condition was optimized and the structures of these compounds have been characterized by NMR and MS.
Three novel calix[6]phyrin derivatives have been synthesized by reaction of corresponding tripyrrane with aromatic aldehyde.The reaction condition was optimized and the structures of these compounds have been characterized by NMR and MS.
2008, 19(10): 1202-1205
doi: 10.1016/j.cclet.2008.07.022
Abstract:
A series of 5-C-alkylating camptothecins have been synthesized by one-step method.and their in vitro antitumor activity was evaluated against six human cancer cell lines.The results showed that all 5-C-alkylatcs of camptothecins possessed poor cytotoxicity on six human cancer cell lines.
A series of 5-C-alkylating camptothecins have been synthesized by one-step method.and their in vitro antitumor activity was evaluated against six human cancer cell lines.The results showed that all 5-C-alkylatcs of camptothecins possessed poor cytotoxicity on six human cancer cell lines.
2008, 19(10): 1206-1208
doi: 10.1016/j.cclet.2008.06.046
Abstract:
Sixteen novel 6-and 2-(1-aeylsulfanylalkyl)-5,8-dimethoxy-1,4-naphthoquinones were designed and synthesized.Their eytotoxicifies were evaluated in vitro against BEL-7402,HT-29 and SPC-Al cell lines.The pharmacological results showed that most of the prepared compounds displayed the excellent selectivity for HT-29 cell line.Compound 16b exhibited the most potent antitumor activity among the tested compounds.
Sixteen novel 6-and 2-(1-aeylsulfanylalkyl)-5,8-dimethoxy-1,4-naphthoquinones were designed and synthesized.Their eytotoxicifies were evaluated in vitro against BEL-7402,HT-29 and SPC-Al cell lines.The pharmacological results showed that most of the prepared compounds displayed the excellent selectivity for HT-29 cell line.Compound 16b exhibited the most potent antitumor activity among the tested compounds.
2008, 19(10): 1209-1211
doi: 10.1016/j.cclet.2008.07.021
Abstract:
A novel hydroxypolyether blocked polydimethylsiloxane,poly(ethylene oxide) propyl-b-polydimethylsiloxane-b-propyl poly(ethylene oxide)(PEO-b-PDMS-b-PEO)was synthesized by simple hydrosilation reaction of poly(ethylene glycol) monoallyl ether with α,ω-dihydrogen terminated PDMS(HPDMS).Fourier transform infrared spectroscopy(FTIR) and 1H NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS.Based on the effect investigations of temperature.reactant molar ratio,catalyst and time on the hydrosilation,it Was found that the conversion of Si-H bond to Si-C bond increased with the increase of catalyst and time,and the reaction completed when the content of catalyst Was 22 μg/g and the time Was 5 h,respectively.Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.
A novel hydroxypolyether blocked polydimethylsiloxane,poly(ethylene oxide) propyl-b-polydimethylsiloxane-b-propyl poly(ethylene oxide)(PEO-b-PDMS-b-PEO)was synthesized by simple hydrosilation reaction of poly(ethylene glycol) monoallyl ether with α,ω-dihydrogen terminated PDMS(HPDMS).Fourier transform infrared spectroscopy(FTIR) and 1H NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS.Based on the effect investigations of temperature.reactant molar ratio,catalyst and time on the hydrosilation,it Was found that the conversion of Si-H bond to Si-C bond increased with the increase of catalyst and time,and the reaction completed when the content of catalyst Was 22 μg/g and the time Was 5 h,respectively.Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.
2008, 19(10): 1212-1214
doi: 10.1016/j.cclet.2008.06.049
Abstract:
Twonew secolignans(1 and 2)were isolated from the roots of Urtica mairei Levl.The structures of these two compounds were determined on the basis of extensive spectroscopic methods including HR-E1-MS.1D and 2D NMR experiments.
Twonew secolignans(1 and 2)were isolated from the roots of Urtica mairei Levl.The structures of these two compounds were determined on the basis of extensive spectroscopic methods including HR-E1-MS.1D and 2D NMR experiments.
2008, 19(10): 1215-1217
doi: 10.1016/j.cclet.2008.06.051
Abstract:
A new sesquilignan,7',8'-didehydroherpetotriol(1),and a new lignan glycoside,(+)-isolariciresinol-9'-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside(2),were isolated from the branches of Dipteronia dyeriana.Their structures were elucidated by spectroscopic methods and chemical evidence.Compound 1 possessed inhibitory activity against human leukaemia K562 cells with an IC50 value of 39 μmol/L.
A new sesquilignan,7',8'-didehydroherpetotriol(1),and a new lignan glycoside,(+)-isolariciresinol-9'-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside(2),were isolated from the branches of Dipteronia dyeriana.Their structures were elucidated by spectroscopic methods and chemical evidence.Compound 1 possessed inhibitory activity against human leukaemia K562 cells with an IC50 value of 39 μmol/L.
2008, 19(10): 1218-1220
doi: 10.1016/j.cclet.2008.06.014
Abstract:
Two new rotenoids 4',5'-dihydroxy-6a,12a-dehydrodeguelin(1),11,4',5'-trihydroxy-6a,12a-dehydrodeguelin(2),along with two known rotenoids rotenone and deguelin were isolated from the root of Derris elliptica collected in Guangdong Province,China.Their structures were established by extensive spectroscopic analysis.
Two new rotenoids 4',5'-dihydroxy-6a,12a-dehydrodeguelin(1),11,4',5'-trihydroxy-6a,12a-dehydrodeguelin(2),along with two known rotenoids rotenone and deguelin were isolated from the root of Derris elliptica collected in Guangdong Province,China.Their structures were established by extensive spectroscopic analysis.
2008, 19(10): 1221-1223
doi: 10.1016/j.cclet.2008.06.013
Abstract:
A new caged polyprenylated xanthone,gambogic aldehyde(1),was isolated from the resin of Garcinia hanburyi.Its structure was elucidated on the basis of spectral data including 1D and 2D NMR data.In addition.the antiproliferative ability of compound 1 was determined in mouse leukemia P388 and P388/ADR ceils.
A new caged polyprenylated xanthone,gambogic aldehyde(1),was isolated from the resin of Garcinia hanburyi.Its structure was elucidated on the basis of spectral data including 1D and 2D NMR data.In addition.the antiproliferative ability of compound 1 was determined in mouse leukemia P388 and P388/ADR ceils.
2008, 19(10): 1224-1227
doi: 10.1016/j.cclet.2008.06.044
Abstract:
From the roots of Picrorhiza scrophulariiflora,two new sccoiridoid glycosides,named picrosecosides I and Ⅱ(1,2)have been isolated.Their structures were elucidated on the basis of chemical and spectropic evidences.
From the roots of Picrorhiza scrophulariiflora,two new sccoiridoid glycosides,named picrosecosides I and Ⅱ(1,2)have been isolated.Their structures were elucidated on the basis of chemical and spectropic evidences.
2008, 19(10): 1228-1230
doi: 10.1016/j.cclet.2008.06.053
Abstract:
Two novel 28-noroleanane-derived spirocyclic triterpenoids with unusual skeleton structures,phlomisone(1),phlomistetraol A (2),were isolated from the roots of Phlomis umbrosa.Their structures were elucidated by spectroscopic methods,including 1D,2D nuclear magnetic resonance(NMR),high-resolution mass spectrometry(HR-MS).
Two novel 28-noroleanane-derived spirocyclic triterpenoids with unusual skeleton structures,phlomisone(1),phlomistetraol A (2),were isolated from the roots of Phlomis umbrosa.Their structures were elucidated by spectroscopic methods,including 1D,2D nuclear magnetic resonance(NMR),high-resolution mass spectrometry(HR-MS).
2008, 19(10): 1231-1233
doi: 10.1016/j.cclet.2008.06.038
Abstract:
A new lipophilic monosaccharide,erigearide A(1),was isolated from the aerial parts of Erigeron annuus(Lima.) Pers.Its structure was elucidated by analysis of spectroscopic evidence.
A new lipophilic monosaccharide,erigearide A(1),was isolated from the aerial parts of Erigeron annuus(Lima.) Pers.Its structure was elucidated by analysis of spectroscopic evidence.
2008, 19(10): 1234-1236
doi: 10.1016/j.cclet.2008.06.041
Abstract:
A new forsythenside,4-hydroxy-4-[8-[[1-[(4-hydroxyphenyl)acetyl]-β-D-glucopymllosyl-6-]oxy]ethyl]-2,5-cyclohexadien-1-one,named forsythenside F, wasisolasted from the plant of Forsythia suspensa(Thunb.) Vahl.The structure of the new compound was established on the basis of various spectroscopic analysis,including 1H NMR, 13C NMR,2D NMR techniques(HMBC and HSQC),and HR-ESI-MS.
A new forsythenside,4-hydroxy-4-[8-[[1-[(4-hydroxyphenyl)acetyl]-β-D-glucopymllosyl-6-]oxy]ethyl]-2,5-cyclohexadien-1-one,named forsythenside F, wasisolasted from the plant of Forsythia suspensa(Thunb.) Vahl.The structure of the new compound was established on the basis of various spectroscopic analysis,including 1H NMR, 13C NMR,2D NMR techniques(HMBC and HSQC),and HR-ESI-MS.
2008, 19(10): 1237-1239
doi: 10.1016/j.cclet.2008.07.023
Abstract:
A new angelol-type coumarin glucoside,6-[(1R,2R)-1,2-dihydroxy-3-β-D-glucosyloxy-3-methylbutyl]-7-methoxycoumarin,wag isolated from the roots of Angelica pubescens.Its structure was elucidated on the basis of spectral analysis.
A new angelol-type coumarin glucoside,6-[(1R,2R)-1,2-dihydroxy-3-β-D-glucosyloxy-3-methylbutyl]-7-methoxycoumarin,wag isolated from the roots of Angelica pubescens.Its structure was elucidated on the basis of spectral analysis.
2008, 19(10): 1240-1243
doi: 10.1016/j.cclet.2008.07.006
Abstract:
A new selective Zn2+ fluorescent chemosensor,o-vanillin-4-ethoxybenzoylhydrazone(1),was designed and prepared.Free 1 mainly displayed very weak fluorescence at 480 nm upone xcitation at 403 nln.It displayed high selectivity for Zn2+ and had a 518-fold fluorescent enhancement upon binding of Zn2+, while the other cation ions had only little influence on the fluorescence of 1.Mechanism of enhancement of 1's fluorescence by Zn2+ was briefly discussed.
A new selective Zn2+ fluorescent chemosensor,o-vanillin-4-ethoxybenzoylhydrazone(1),was designed and prepared.Free 1 mainly displayed very weak fluorescence at 480 nm upone xcitation at 403 nln.It displayed high selectivity for Zn2+ and had a 518-fold fluorescent enhancement upon binding of Zn2+, while the other cation ions had only little influence on the fluorescence of 1.Mechanism of enhancement of 1's fluorescence by Zn2+ was briefly discussed.
2008, 19(10): 1244-1247
doi: 10.1016/j.cclet.2008.06.036
Abstract:
An electrochemical method for the simultaneous detection of two different DNA sequenees from PAT and FMV 35S gene sequence using CdS and PbS quantum dots (QDs)as labels was described.The QDs were readily functionalized with oligonucleotides as electrochemical DNA probes and selectively hybridized to the complementary sequences immobilized on the microplate.The QDs anchored on the hybrids were dissolved in the solution by the oxidation of HNO3 and further detected by a sensitive differential pulse anodic stripping voltammetric method(DPASV).The DPASV signals of the oxidation of Cd2+ and Pb2+ ions present in the solution were difierent and reflected the identity of corresponding ssDNA targets sequences.
An electrochemical method for the simultaneous detection of two different DNA sequenees from PAT and FMV 35S gene sequence using CdS and PbS quantum dots (QDs)as labels was described.The QDs were readily functionalized with oligonucleotides as electrochemical DNA probes and selectively hybridized to the complementary sequences immobilized on the microplate.The QDs anchored on the hybrids were dissolved in the solution by the oxidation of HNO3 and further detected by a sensitive differential pulse anodic stripping voltammetric method(DPASV).The DPASV signals of the oxidation of Cd2+ and Pb2+ ions present in the solution were difierent and reflected the identity of corresponding ssDNA targets sequences.
2008, 19(10): 1248-1251
doi: 10.1016/j.cclet.2008.07.003
Abstract:
This paper presents the enantioseparation using glucose,cellobiose,lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC.Surprisingly,they also possess high enantioseparation selectivity,may be used in normal-phase and reversedphase mode.and there is a big chiral discriminating complementary.This work indicates that oligosacchafides could soon become very attractive as a new class of chiral stationary phase for HPLC.
This paper presents the enantioseparation using glucose,cellobiose,lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC.Surprisingly,they also possess high enantioseparation selectivity,may be used in normal-phase and reversedphase mode.and there is a big chiral discriminating complementary.This work indicates that oligosacchafides could soon become very attractive as a new class of chiral stationary phase for HPLC.
Influence of alkali mixed effect on the mixing enthalpy in 0.75B2O3-0.25[xNa2O-(1-x)K2O]glass system
2008, 19(10): 1252-1255
doi: 10.1016/j.cclet.2008.06.034
Abstract:
The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-(1-x)K2O]through thermodynamic properties.The calorimetric measurements were performed in HF solution calorimetry at 298 K,The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another.This thermodynamic non-idealiIy is caused by the slight variations of distance between metallic cations,the macromolecular structure being unchanged.It can be explained,at least qualitatively,using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hiickel.
The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-(1-x)K2O]through thermodynamic properties.The calorimetric measurements were performed in HF solution calorimetry at 298 K,The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another.This thermodynamic non-idealiIy is caused by the slight variations of distance between metallic cations,the macromolecular structure being unchanged.It can be explained,at least qualitatively,using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hiickel.
2008, 19(10): 1256-1259
doi: 10.1016/j.cclet.2008.06.054
Abstract:
Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ(BCNd5)was prepared by pressing followed by sintering.X-ray diffraction(XRD)was used to characterize the phase structure of both the powder and the sintered membranes.The microstructure of the sintered membranes was studied by scanning electron microscopy(SEM).Hydrogen permeation through the BCNd5 membrane was studied using a high temperature permeator.The hydrogen permeation fluxes under wet conditions are higher than those under dry conditions,which is due to H+ hopping via surface OH groups.At 925℃,a hydrogen permeation flux of 0.02 mL/min cm2 was obtained under wet condition.which recommends BCNd5 as a potential material for hydrogen-selective membranes.
Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ(BCNd5)was prepared by pressing followed by sintering.X-ray diffraction(XRD)was used to characterize the phase structure of both the powder and the sintered membranes.The microstructure of the sintered membranes was studied by scanning electron microscopy(SEM).Hydrogen permeation through the BCNd5 membrane was studied using a high temperature permeator.The hydrogen permeation fluxes under wet conditions are higher than those under dry conditions,which is due to H+ hopping via surface OH groups.At 925℃,a hydrogen permeation flux of 0.02 mL/min cm2 was obtained under wet condition.which recommends BCNd5 as a potential material for hydrogen-selective membranes.
2008, 19(10): 1260-1263
doi: 10.1016/j.cclet.2008.07.008
Abstract:
An asymmetrical perylene diimide 3,N-(4-methoxyphenyl)-N'-(4-nitrophenyl)-perylene-3,4,9,10-tetracarboxylic diimide,was synthesized,and its self-assembly and dissociation behaviors in chloroform was studied in detail bv UV-vis and fluorescence spectroscopies.The resulting unique helical nanostructures from 3 were proposed to be self-assembled via the cooperative actions of π-π stacking,steric hindrance and electrophile-nucleophile type pairing.
An asymmetrical perylene diimide 3,N-(4-methoxyphenyl)-N'-(4-nitrophenyl)-perylene-3,4,9,10-tetracarboxylic diimide,was synthesized,and its self-assembly and dissociation behaviors in chloroform was studied in detail bv UV-vis and fluorescence spectroscopies.The resulting unique helical nanostructures from 3 were proposed to be self-assembled via the cooperative actions of π-π stacking,steric hindrance and electrophile-nucleophile type pairing.
