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1995 Volume 6 Issue 2
1995, 6(2): 95-98
Abstract:
The azole anions behave as nucleophiles towards nitro-substituted halobenzene,indicating a classical SNAr mechanism,and the nucleophilicity of azole anions is consistent wtih the pKa values
The azole anions behave as nucleophiles towards nitro-substituted halobenzene,indicating a classical SNAr mechanism,and the nucleophilicity of azole anions is consistent wtih the pKa values
1995, 6(2): 99-100
Abstract:
Twelve new compounds with the formula of Ph3GeCHR1CH2CONHNHC(X)NHR2(R1=H,Ph;X=S,O,R2=Ph,p-C1Ph,p-CH3Ph,o-CH3Ph,COPh)were synthesized by the reaction of Ph,Ge CHR1CH2CONHNH2with R2NCX in good yield(77-94%)
Twelve new compounds with the formula of Ph3GeCHR1CH2CONHNHC(X)NHR2(R1=H,Ph;X=S,O,R2=Ph,p-C1Ph,p-CH3Ph,o-CH3Ph,COPh)were synthesized by the reaction of Ph,Ge CHR1CH2CONHNH2with R2NCX in good yield(77-94%)
1995, 6(2): 101-102
Abstract:
Five C19-diterpenoid alkaloids were isolated from the aerial parts of Delphinium mollipilum W.T.Wang.Four proved to be the known talitine B,talitme A,brownine and delcosine,while the fifth was a new C19-diterpenoid alkaloid,molline,whose structure was established by spectral methods.
Five C19-diterpenoid alkaloids were isolated from the aerial parts of Delphinium mollipilum W.T.Wang.Four proved to be the known talitine B,talitme A,brownine and delcosine,while the fifth was a new C19-diterpenoid alkaloid,molline,whose structure was established by spectral methods.
1995, 6(2): 103-104
Abstract:
A new ceramide,biemnamide,was isolated from the marine aponge Blemna sp.collected from the South China Sea and its structure was eatablished by spectroscopic analysis.
A new ceramide,biemnamide,was isolated from the marine aponge Blemna sp.collected from the South China Sea and its structure was eatablished by spectroscopic analysis.
1995, 6(2): 105-108
Abstract:
Two new triterpenoid saponins named asterbatanoside H and I have been isolated from the roots of Aster batangensis and their structures elucidated as 3-O-β-D-glucopyranosyl-(1→3)β-D-glucopyranosyl-bayogenin-28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside and 3-O-β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-23-O-acetyl-bayogenin-28-O-β-D-glucopyranosyl-(1→6)β-D-glucopyranoside,respectively,by means of spectral and chemical data.
Two new triterpenoid saponins named asterbatanoside H and I have been isolated from the roots of Aster batangensis and their structures elucidated as 3-O-β-D-glucopyranosyl-(1→3)β-D-glucopyranosyl-bayogenin-28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside and 3-O-β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-23-O-acetyl-bayogenin-28-O-β-D-glucopyranosyl-(1→6)β-D-glucopyranoside,respectively,by means of spectral and chemical data.
1995, 6(2): 109-110
Abstract:
A new C19-diterpenoid alkaloid,1-cpicrassicaudine,was isolated from the roots of Aconitum hemslevanum Pritz var.pengshinese.Speetral methods demonstrated that it has the structure represented by(1)an 1-epimer of crassieau-dine
A new C19-diterpenoid alkaloid,1-cpicrassicaudine,was isolated from the roots of Aconitum hemslevanum Pritz var.pengshinese.Speetral methods demonstrated that it has the structure represented by(1)an 1-epimer of crassieau-dine
1995, 6(2): 111-112
Abstract:
A new eudesmane sesquiterpene was isolated from the root of Rhaponticum uniflorum(Compositae)and Its structure was elucidated on the basis of spectra method(IR,EIMS,1H-NMR,13C-NMR,DEPT and1H,1H-Cosy)as 7α,8α,13-trihydroxy-eudesm-△4(14)-△11(12)-diene.
A new eudesmane sesquiterpene was isolated from the root of Rhaponticum uniflorum(Compositae)and Its structure was elucidated on the basis of spectra method(IR,EIMS,1H-NMR,13C-NMR,DEPT and1H,1H-Cosy)as 7α,8α,13-trihydroxy-eudesm-△4(14)-△11(12)-diene.
1995, 6(2): 113-116
Abstract:
The fluorescence spectra and photodimerization of naphthalene end-labelled poly(ethylene glycol)oligomers(N-Pn-N)in methanol in the prescence of alkali cations have been investigated.The ion enhances or inhibits intramolecular excimer formation and photodimerization of N-Pn-N,depending on the size of the ion and the length of the polyether chain.This observation suggests that the polyether chain binds the ion,thus adopts a crown ether-like conformation.
The fluorescence spectra and photodimerization of naphthalene end-labelled poly(ethylene glycol)oligomers(N-Pn-N)in methanol in the prescence of alkali cations have been investigated.The ion enhances or inhibits intramolecular excimer formation and photodimerization of N-Pn-N,depending on the size of the ion and the length of the polyether chain.This observation suggests that the polyether chain binds the ion,thus adopts a crown ether-like conformation.
1995, 6(2): 117-120
Abstract:
Melittin is a small basic peptide which has a high affinity for calmodulin(CaM).In a previous paper,the authors have demonstrated that the deletion peptide Mel(12~25),that is,Mel15 has almost the same binding activity as the intact native peptide(1).In this study,three analogues of Mel15 were synthesized,the role of amphiphilic α-helix of peptides on their binding to CaM were studied.According to the calculation of hydrophobic moment and the analysis of the secondary structure,we proposed that the role of amphiphilic structure is not absolute,since the dissociation constants for the binding of different analogs to CaM bear no predictable relation to the calculated hydrophobic moment and the average hydrophobicity
Melittin is a small basic peptide which has a high affinity for calmodulin(CaM).In a previous paper,the authors have demonstrated that the deletion peptide Mel(12~25),that is,Mel15 has almost the same binding activity as the intact native peptide(1).In this study,three analogues of Mel15 were synthesized,the role of amphiphilic α-helix of peptides on their binding to CaM were studied.According to the calculation of hydrophobic moment and the analysis of the secondary structure,we proposed that the role of amphiphilic structure is not absolute,since the dissociation constants for the binding of different analogs to CaM bear no predictable relation to the calculated hydrophobic moment and the average hydrophobicity
1995, 6(2): 121-122
Abstract:
In this paper,p-dibromobenzene,p-dimethoxybenzene,p-diethoxy-benzene and p-dibutoxybenzene were synthesized using bromobenzene and hydroquinone.Their polymers,poly-p-phenylene,poly-(2,5-dimethoxy)-p-phenylene,poly-p-(2,5-diethoxy)-p-phenylene and poly-(2,5-dibutoxy)-p-phenylene were also synthesized and their IR spectra were done and conductivity was measured.
In this paper,p-dibromobenzene,p-dimethoxybenzene,p-diethoxy-benzene and p-dibutoxybenzene were synthesized using bromobenzene and hydroquinone.Their polymers,poly-p-phenylene,poly-(2,5-dimethoxy)-p-phenylene,poly-p-(2,5-diethoxy)-p-phenylene and poly-(2,5-dibutoxy)-p-phenylene were also synthesized and their IR spectra were done and conductivity was measured.
1995, 6(2): 123-126
Abstract:
We report here a fast staining method for single-stranded DNA fixed on nitrocellulose membrane using M-meso-tetra(3-N-methylpyridyl)-porphyrin(M-TMPyP,M:Mn3+,Fe3+,Pt+).The optimal staining solution consists of 54~108μg/ml M-TMPyP in 25~200 mmol/L phosphate buffer solution(pH 5.0~8.0).When DNA dot on NC membrane is treated with the staining solution at room temperature for 1~2 minutes with continuous stirring,it turns to brown-yellow.10pg per dot of single-stranded DNA is visible.It is a useful tool to study the DNA blotting,and for recognition of the special bands of DNA in a complete electrophoretogram of DNA blot.The staining mechanism is also discussed.
We report here a fast staining method for single-stranded DNA fixed on nitrocellulose membrane using M-meso-tetra(3-N-methylpyridyl)-porphyrin(M-TMPyP,M:Mn3+,Fe3+,Pt+).The optimal staining solution consists of 54~108μg/ml M-TMPyP in 25~200 mmol/L phosphate buffer solution(pH 5.0~8.0).When DNA dot on NC membrane is treated with the staining solution at room temperature for 1~2 minutes with continuous stirring,it turns to brown-yellow.10pg per dot of single-stranded DNA is visible.It is a useful tool to study the DNA blotting,and for recognition of the special bands of DNA in a complete electrophoretogram of DNA blot.The staining mechanism is also discussed.
1995, 6(2): 127-128
Abstract:
Three kinds of Co sites.i.e.tetrahedral(Co[T]),octahedral(Co[O])cobalt sites and bulk Co3O4are characterized by infrared spectroscopy of CO and NO adsorbed on reduced and sulfided CO/AI2O3at room temperature.
Three kinds of Co sites.i.e.tetrahedral(Co[T]),octahedral(Co[O])cobalt sites and bulk Co3O4are characterized by infrared spectroscopy of CO and NO adsorbed on reduced and sulfided CO/AI2O3at room temperature.
1995, 6(2): 129-130
Abstract:
The mathematical equations of the effective percentage of a complexant and its complex-ratio with a metal have been developed by means of the β-correction pinciple.From a real abeorbance of the chelate produced,its true abeorptivity can be determined accurately.The β-correction spectrophotometry was studied for the determinations of the desired parameters above,using the reaction of lead with Eriochrome Black T(EBT)at pH 8.2.The results show that the analytical ansitivity and precision by β-correction method are both much higher than those by the single wavelength method,the complex-ratio of Pb(Ⅱ)with EBT equals to 1:4 and the true molar absorptivity of Pb(EBT)4chelate at 550 nm is 3.53×104L.mol-1.cm-1.
The mathematical equations of the effective percentage of a complexant and its complex-ratio with a metal have been developed by means of the β-correction pinciple.From a real abeorbance of the chelate produced,its true abeorptivity can be determined accurately.The β-correction spectrophotometry was studied for the determinations of the desired parameters above,using the reaction of lead with Eriochrome Black T(EBT)at pH 8.2.The results show that the analytical ansitivity and precision by β-correction method are both much higher than those by the single wavelength method,the complex-ratio of Pb(Ⅱ)with EBT equals to 1:4 and the true molar absorptivity of Pb(EBT)4chelate at 550 nm is 3.53×104L.mol-1.cm-1.
1995, 6(2): 131-134
Abstract:
It has been found that the peak current in KRPB solution is of good linear dependence on the concentration of glucose.According to this relation,the standard curve is plotted and the results of determination of glucose concentration have been presented in the urine of diabetes mellitus.The interference from endogenous oxidizable substances such as uric acid,urea,as well as the effect of chloride on glucose response are also studied.
It has been found that the peak current in KRPB solution is of good linear dependence on the concentration of glucose.According to this relation,the standard curve is plotted and the results of determination of glucose concentration have been presented in the urine of diabetes mellitus.The interference from endogenous oxidizable substances such as uric acid,urea,as well as the effect of chloride on glucose response are also studied.
STUDY OF THE FLUORESCENCE SYSTEM OF RIBONUCLEIC ACID-Tb（Ⅲ） AND THE DETERMINATION OF RIBONUCLEIC ACID
1995, 6(2): 135-138
Abstract:
It was found that ribonucleic acid(RNA)compiexes with Tb(Ⅲ)at pH=5.0-6.5,which then emits strong characterlstic fluorescence of Tb(Ⅲ).The excitation and emission wavelengths are 288nm,494nm and 545nm,respectively.A linear relationship is obtained between the fluorescence intensity and RNA concentration in the range of 0.1 ug/ml-10 ug/ml.The detection limit is 8.0×10-10mol/L.This method can be used to determine RNA in the presence of adenylic acid,uridylic acid and cytidylic aci.
It was found that ribonucleic acid(RNA)compiexes with Tb(Ⅲ)at pH=5.0-6.5,which then emits strong characterlstic fluorescence of Tb(Ⅲ).The excitation and emission wavelengths are 288nm,494nm and 545nm,respectively.A linear relationship is obtained between the fluorescence intensity and RNA concentration in the range of 0.1 ug/ml-10 ug/ml.The detection limit is 8.0×10-10mol/L.This method can be used to determine RNA in the presence of adenylic acid,uridylic acid and cytidylic aci.
1995, 6(2): 139-140
Abstract:
The electrochemical behaviours of three kinds of soluble polyimides were investigated for the first time.It was observed that the cyclic voltammograms(CVs)of these polyimides in nonaqueous solutions are obviously different from that of the polyimide films casted on surfaces of glass carbon electrode(GCEs) in aqueous solutions
The electrochemical behaviours of three kinds of soluble polyimides were investigated for the first time.It was observed that the cyclic voltammograms(CVs)of these polyimides in nonaqueous solutions are obviously different from that of the polyimide films casted on surfaces of glass carbon electrode(GCEs) in aqueous solutions
1995, 6(2): 141-142
Abstract:
The design and testing of amperometric glucose biosensor was described,in which electrical communication between the flavin redox centers of glucose oxidase and a conventional carbon paste electrode has been achieved by using electron-transfer mediator based on tetrabutylammonium-tetra-cyanoquinodimethane(TBA+-TCNQ-).Characteristics of the biosensor has been shown by cyclic voltammetry.The experimental results show that TBA+-TCNQ-can act as an efficient electron transfer mediator between GODox/GODredcenters and a carbon paste electrode
The design and testing of amperometric glucose biosensor was described,in which electrical communication between the flavin redox centers of glucose oxidase and a conventional carbon paste electrode has been achieved by using electron-transfer mediator based on tetrabutylammonium-tetra-cyanoquinodimethane(TBA+-TCNQ-).Characteristics of the biosensor has been shown by cyclic voltammetry.The experimental results show that TBA+-TCNQ-can act as an efficient electron transfer mediator between GODox/GODredcenters and a carbon paste electrode
1995, 6(2): 143-146
Abstract:
Electrochemical reduction of flavone 1 in ethanol-sulphuric acid solution with lead electrode gave flavanone 3 and 2-2"coupled biflavanones:2a(racemate)and 2b(meso).The configuration of 2a was determined by X-ray crystallography.
Electrochemical reduction of flavone 1 in ethanol-sulphuric acid solution with lead electrode gave flavanone 3 and 2-2"coupled biflavanones:2a(racemate)and 2b(meso).The configuration of 2a was determined by X-ray crystallography.
1995, 6(2): 147-148
Abstract:
Water-soluble ytterbium complex of tetra-p-sulfonatophenylporphyrin(H2TPPS)with the formulation Yb·TPPS·OH·2 im·3H2O(im=imidazole),stable in pH≥5 solution,has been synthesized and characterized by elemental analysis,IR and electronic absorption spectroscopy.Its structure is also proposed.The ytterbium atom exhibits a coordination number of seven with the ytterbium atom out of the porphyrin plane.
Water-soluble ytterbium complex of tetra-p-sulfonatophenylporphyrin(H2TPPS)with the formulation Yb·TPPS·OH·2 im·3H2O(im=imidazole),stable in pH≥5 solution,has been synthesized and characterized by elemental analysis,IR and electronic absorption spectroscopy.Its structure is also proposed.The ytterbium atom exhibits a coordination number of seven with the ytterbium atom out of the porphyrin plane.
1995, 6(2): 149-152
Abstract:
Manganese(Ⅲ)porphyrins bound to chloromethylated polystyrene bearing some polyglycol chains are efficient catalysts for the epoxidation of styrene by sodium hypochlorite
Manganese(Ⅲ)porphyrins bound to chloromethylated polystyrene bearing some polyglycol chains are efficient catalysts for the epoxidation of styrene by sodium hypochlorite
1995, 6(2): 153-154
Abstract:
The synthesis and characterization of the previously unreported[ZnW11O39Ti(H2O)]6-polyoxoanion is described.Also reported is a survey of the catalytic epoxidatioa of five olefinic substrates PhIO or 30%aqueous H2O2 using this heteropolyanion as a catalyst.
The synthesis and characterization of the previously unreported[ZnW11O39Ti(H2O)]6-polyoxoanion is described.Also reported is a survey of the catalytic epoxidatioa of five olefinic substrates PhIO or 30%aqueous H2O2 using this heteropolyanion as a catalyst.
1995, 6(2): 155-158
Abstract:
The alkenc cpoxidation by iodosylbenzene can be catalyzed by transition metal substituted polyoxomctalates.Among the polyoxometalates examined β-SiW9M3,and ZnW11Ti was found to be the most efficient catalyst.The oxidations with sodium periodatc are very selective to alkenc cleavage
The alkenc cpoxidation by iodosylbenzene can be catalyzed by transition metal substituted polyoxomctalates.Among the polyoxometalates examined β-SiW9M3,and ZnW11Ti was found to be the most efficient catalyst.The oxidations with sodium periodatc are very selective to alkenc cleavage
1995, 6(2): 159-162
Abstract:
The epoxidation of allyl alcohol and maleic acid by hydrogcn peroxide can be catalyzed by transition metal substituted polyoxometalates.The transition metal substituted polyoxometalates-hydrogenperoxide system provides an alternative method to prepare cpoxyacids and cpoxy alcohols.
The epoxidation of allyl alcohol and maleic acid by hydrogcn peroxide can be catalyzed by transition metal substituted polyoxometalates.The transition metal substituted polyoxometalates-hydrogenperoxide system provides an alternative method to prepare cpoxyacids and cpoxy alcohols.
1995, 6(2): 163-164
Abstract:
RuⅢ(NH3)6in the cages of NaX zeolite was converted in the presence of CO+H2into[Ru6(CO)18]2-,which was characterized by in-situ FTIR,UV-VIS and EXAFS spectroscopies.The material derived from[Ru6(CO)18]2-/NaX exhibited high catalytic activity in n-butane hydrogenolysis.
RuⅢ(NH3)6in the cages of NaX zeolite was converted in the presence of CO+H2into[Ru6(CO)18]2-,which was characterized by in-situ FTIR,UV-VIS and EXAFS spectroscopies.The material derived from[Ru6(CO)18]2-/NaX exhibited high catalytic activity in n-butane hydrogenolysis.
1995, 6(2): 165-166
Abstract:
A new method(premodification)is proposed to manufacture inorganic membrane.A series of metal oxide(NiO,CoO,La2O3,Ce2O3,Sm2O3Y2O3)modified inorganic membranes are successfully developed and are characterized by QELS,BET,XRD and DTA.The membranes have a very narrow pore size distribution and the pore size is around 4-10nm.The metal oxide is believed to be a monolayer on the surface of γ-Al2O3.The temperature influence has also been investigated.
A new method(premodification)is proposed to manufacture inorganic membrane.A series of metal oxide(NiO,CoO,La2O3,Ce2O3,Sm2O3Y2O3)modified inorganic membranes are successfully developed and are characterized by QELS,BET,XRD and DTA.The membranes have a very narrow pore size distribution and the pore size is around 4-10nm.The metal oxide is believed to be a monolayer on the surface of γ-Al2O3.The temperature influence has also been investigated.
1995, 6(2): 167-168
Abstract:
Nanometer perovskite-type complex oxide LaMnO3with average size of 18.7nm was prepared by sol-gel method,and it exhibited much higher catalytic activity for complete oxidation of methane than that of LaMnO3with large particle size.The increasing of catalytic activity may be attributed to the increasing of surface area and the change of surface structure for nanometer LaMnO3.
Nanometer perovskite-type complex oxide LaMnO3with average size of 18.7nm was prepared by sol-gel method,and it exhibited much higher catalytic activity for complete oxidation of methane than that of LaMnO3with large particle size.The increasing of catalytic activity may be attributed to the increasing of surface area and the change of surface structure for nanometer LaMnO3.
1995, 6(2): 169-172
Abstract:
N2-H2O system was studied by ab initio SCF calculations with a 6-31G** basis set.The results were fitted to an analytical function assuming pairwise additivity for the interaction between individual centres.The analytical funetions were Lennard-Jones 10-6 and exponential form.A satisfactory fitting result was achieved by the simulated anneal algorithm.Special care was paid to repulsive region,which gives the important contributions to the formation of the first solvation shell of apoler solutes.
N2-H2O system was studied by ab initio SCF calculations with a 6-31G** basis set.The results were fitted to an analytical function assuming pairwise additivity for the interaction between individual centres.The analytical funetions were Lennard-Jones 10-6 and exponential form.A satisfactory fitting result was achieved by the simulated anneal algorithm.Special care was paid to repulsive region,which gives the important contributions to the formation of the first solvation shell of apoler solutes.
