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1999 Volume 10 Issue 10
1999, 10(10): 811-812
Abstract:
3-Acetyl-7-hydroxy-8-methyl-6-nitrocoumarin reacted with substituted anilines, and fission of the heterocyclic ring occurred.
3-Acetyl-7-hydroxy-8-methyl-6-nitrocoumarin reacted with substituted anilines, and fission of the heterocyclic ring occurred.
1999, 10(10): 813-816
Abstract:
Synthesis of α-aminoarylacetic acids with good yield in the presence of phase transfer catalyst (PTC) under sonication has been studied. Results obtained are superior to those by other similar methods. The data show that β-cyclodextrin(β-CD) is a more efficient catalyst than other PTC. Optimum reaction conditions and a preliminary mechanism are also discussed.
Synthesis of α-aminoarylacetic acids with good yield in the presence of phase transfer catalyst (PTC) under sonication has been studied. Results obtained are superior to those by other similar methods. The data show that β-cyclodextrin(β-CD) is a more efficient catalyst than other PTC. Optimum reaction conditions and a preliminary mechanism are also discussed.
1999, 10(10): 817-820
Abstract:
Amurensin H(1) is a new resveratrol dimer isolated from the roots of Vitis amurensis Rupr. Its structure was determined by spectroscopic methods. It was synthesized from resveratrol with an oxidative coupling reaction as a key step.
Amurensin H(1) is a new resveratrol dimer isolated from the roots of Vitis amurensis Rupr. Its structure was determined by spectroscopic methods. It was synthesized from resveratrol with an oxidative coupling reaction as a key step.
1999, 10(10): 821-824
Abstract:
An efficient synthesis and screening of twenty one osteostatin(OSN) analogues were achieved by using pooling strategy. Three analogues were found to retain almost the same activity of inhibiting bone resorption in rat as that of OSN. Therefore, it is possible to develop partially modified OSN surrogate with higher enzymic stability.
An efficient synthesis and screening of twenty one osteostatin(OSN) analogues were achieved by using pooling strategy. Three analogues were found to retain almost the same activity of inhibiting bone resorption in rat as that of OSN. Therefore, it is possible to develop partially modified OSN surrogate with higher enzymic stability.
1999, 10(10): 825-826
Abstract:
One new sesquiterpene polyol ester named angulatin C was isolated from the root bark of Celastrus angulatus along with a known compound, angulatin B.Their structures were elucidated on the basis of spectral analysis.
One new sesquiterpene polyol ester named angulatin C was isolated from the root bark of Celastrus angulatus along with a known compound, angulatin B.Their structures were elucidated on the basis of spectral analysis.
1999, 10(10): 827-830
Abstract:
Two new C20 hetisine-type diterpenoid alkaloids, spirafine Ⅲ (1) and spirafine Ⅱ (2), were isolated from the roots of spiraea fritschiana var. parvifolia. Their structures were elucidated based on HRMS, IR and NMR spectral data, and chemical reaction.
Two new C20 hetisine-type diterpenoid alkaloids, spirafine Ⅲ (1) and spirafine Ⅱ (2), were isolated from the roots of spiraea fritschiana var. parvifolia. Their structures were elucidated based on HRMS, IR and NMR spectral data, and chemical reaction.
1999, 10(10): 831-832
Abstract:
Four basic drugs were separated by capillary electrophoresis (CE) using carboxymethyl-β-cyclodextrin (CM-β-CD) as chiral selector The effects of CM-β-CD concentration, applied voltage, operation temperature were investigated. Under the selected conditions; norephedrine, ofloxacin; terbutaline and chlorpheniramine were enantiomerally baseline-separated using H3P04-triethanolamine buffer at pH 3 containing 10, 5.5, 2, 2mmo1/L CM-β-CD respectively.
Four basic drugs were separated by capillary electrophoresis (CE) using carboxymethyl-β-cyclodextrin (CM-β-CD) as chiral selector The effects of CM-β-CD concentration, applied voltage, operation temperature were investigated. Under the selected conditions; norephedrine, ofloxacin; terbutaline and chlorpheniramine were enantiomerally baseline-separated using H3P04-triethanolamine buffer at pH 3 containing 10, 5.5, 2, 2mmo1/L CM-β-CD respectively.
1999, 10(10): 833-834
Abstract:
The dissociation routes of the adduct ions [M+CH3CO]+ formed by ion-molecule reaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionisation condition were investigated by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.
The dissociation routes of the adduct ions [M+CH3CO]+ formed by ion-molecule reaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionisation condition were investigated by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.
1999, 10(10): 835-838
Abstract:
Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals)，ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of 4-methyl-3-penten-2-one. The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the functional vibrational modes.
Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals)，ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of 4-methyl-3-penten-2-one. The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the functional vibrational modes.
1999, 10(10): 839-842
Abstract:
The line positions of 19F NMR absorption of fluoranil (TFQ) or pentafluorophenyl carboxylate (PFE-16) in the presence of N-alkylphenothiazine donors have been measured. By comparing the 19F chemical shift in C6D6 of TFQ or PFE-16 in the absence of the donor with those in the presence of the: donor. the difference of these chemical shifts was found to be large. In the presence of the donor, 19F upheld shifts of TFQ or PFE-16 have been observed. The experimental results showed that there is a charge-transfer process between TFQ or PFE-16 and the donor. When TFQ or PFE-16 accepts the charge from the donor, its 19F resonance moves upheld.
The line positions of 19F NMR absorption of fluoranil (TFQ) or pentafluorophenyl carboxylate (PFE-16) in the presence of N-alkylphenothiazine donors have been measured. By comparing the 19F chemical shift in C6D6 of TFQ or PFE-16 in the absence of the donor with those in the presence of the: donor. the difference of these chemical shifts was found to be large. In the presence of the donor, 19F upheld shifts of TFQ or PFE-16 have been observed. The experimental results showed that there is a charge-transfer process between TFQ or PFE-16 and the donor. When TFQ or PFE-16 accepts the charge from the donor, its 19F resonance moves upheld.
1999, 10(10): 843-844
Abstract:
It was found that microperoxidase-11 (MP-11) can undergo photoreduction at the bare roughened silver electrode. No photoreduction happens at the roughened silver electrode modified with mercaptoundecanoic carboxylic acid/poly-lysine. The photoreduction mechanism is discussed.
It was found that microperoxidase-11 (MP-11) can undergo photoreduction at the bare roughened silver electrode. No photoreduction happens at the roughened silver electrode modified with mercaptoundecanoic carboxylic acid/poly-lysine. The photoreduction mechanism is discussed.
1999, 10(10): 845-848
Abstract:
The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen amities and catalytic activities to epoxidize styrene were also investigated.
The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen amities and catalytic activities to epoxidize styrene were also investigated.
1999, 10(10): 849-850
Abstract:
β-Galactosidase, a kind of endoenzyme in E. coli cells, can be released by the poreforming action of colicin E1, and E.coli can be detected rapidly by enzymatic method.
β-Galactosidase, a kind of endoenzyme in E. coli cells, can be released by the poreforming action of colicin E1, and E.coli can be detected rapidly by enzymatic method.
1999, 10(10): 851-854
Abstract:
A new method for the determination of cerium subgroup rare earths was studied and reported in this paper. It was found that cerium subgrouo rare earth elements react with DBMCSA in 0.6 mol/L hydrochloric acid medium to form stable blue complexes. absorbances of eyual amounts of cerium subgroup rare earths are close to each other at their maximum adsorptive wavelength (641 nm). Beer's law is obeyed for 0-20 μg of rare earths in 25 ml of solution. The method has been applied to the determination of the total amount of cerium subgroup rare earths in steel and cast iron samples with satisfactory results.
A new method for the determination of cerium subgroup rare earths was studied and reported in this paper. It was found that cerium subgrouo rare earth elements react with DBMCSA in 0.6 mol/L hydrochloric acid medium to form stable blue complexes. absorbances of eyual amounts of cerium subgroup rare earths are close to each other at their maximum adsorptive wavelength (641 nm). Beer's law is obeyed for 0-20 μg of rare earths in 25 ml of solution. The method has been applied to the determination of the total amount of cerium subgroup rare earths in steel and cast iron samples with satisfactory results.
1999, 10(10): 855-856
Abstract:
In 0.10mol/L HOAc-NaOAc buffer solution (pH 4.59), a sensitive reduction peak of bleomycin is obtained by linear sweep voltammetry at Co/GC ion implantation modified electrode. Its electrochemical behavior has been studied. The experiments of AES and XPS Show that Co is surely implanted into the surface of GCE and improved the electrocatalytic activity.
In 0.10mol/L HOAc-NaOAc buffer solution (pH 4.59), a sensitive reduction peak of bleomycin is obtained by linear sweep voltammetry at Co/GC ion implantation modified electrode. Its electrochemical behavior has been studied. The experiments of AES and XPS Show that Co is surely implanted into the surface of GCE and improved the electrocatalytic activity.
1999, 10(10): 857-860
Abstract:
It was newly found that the electrodes modified by applying ethanol solutions of Nation containing Os(bpy)32+ onto the substrate electrode (the one=step method) show two pairs of stable redox peaks of Os(bpy)32+/3+ on cyclic voltammogram near 0.54V and 0.25V, respectively. These modified electrodes can effectively mediate and catalyze the first and second steps of nitrite reduction in acidic media in the potential region 0-0.9V when the loading in the coating (X=Γ(Os2+)/Γ(S03+)) and pH in solution are below 0.17 and 4, respectively. When X is between 0.33 and 0.17, only the current peak near 0.54V appears regardless of solution pH and only the first step of NO2+ reduction is catalyzed. Thus the modified electrode provides a very useful flexibility that one can control the reaction pathway and catalytic activity of nitrite reduction by simply changing the concentration of the mediator in the coating.
It was newly found that the electrodes modified by applying ethanol solutions of Nation containing Os(bpy)32+ onto the substrate electrode (the one=step method) show two pairs of stable redox peaks of Os(bpy)32+/3+ on cyclic voltammogram near 0.54V and 0.25V, respectively. These modified electrodes can effectively mediate and catalyze the first and second steps of nitrite reduction in acidic media in the potential region 0-0.9V when the loading in the coating (X=Γ(Os2+)/Γ(S03+)) and pH in solution are below 0.17 and 4, respectively. When X is between 0.33 and 0.17, only the current peak near 0.54V appears regardless of solution pH and only the first step of NO2+ reduction is catalyzed. Thus the modified electrode provides a very useful flexibility that one can control the reaction pathway and catalytic activity of nitrite reduction by simply changing the concentration of the mediator in the coating.
1999, 10(10): 861-862
Abstract:
Alternating pulses current一chronopotentiometric stripping analysis (APC-CPSA) is a new method as a variant of chronopotentiometric stripping analysis (CPSA). During the stripping step an alternating pulse current with a high frequency in a square wave mode is imposed on the electrode system. Thus, τ and sensitivity of APC-CPSA is increased a lot. The τ, E~t equation and its reciprocal derivative equation for APC-CPSA are derived and verified by the experimental results.
Alternating pulses current一chronopotentiometric stripping analysis (APC-CPSA) is a new method as a variant of chronopotentiometric stripping analysis (CPSA). During the stripping step an alternating pulse current with a high frequency in a square wave mode is imposed on the electrode system. Thus, τ and sensitivity of APC-CPSA is increased a lot. The τ, E~t equation and its reciprocal derivative equation for APC-CPSA are derived and verified by the experimental results.
1999, 10(10): 863-866
Abstract:
The electrocatalytic oxidation of hypophosphite on a nickel electrode has been studied by means of in situ UV-Vis subtractive reflectance spectroscopy. An absorbency band around 245 nm, which was ascribed to the formation of an intermediate,· PHO2-, was observed in the electrocatalytic oxidation process. Accordingly, the electrocatalytic oxidation of hypophosphite might undergo a H abstraction of hypophosphite from the P-H bond to form the phosphoruscentred radical, · PHO2-, which is subsequently electrooxidized to the final product, phosphite.
The electrocatalytic oxidation of hypophosphite on a nickel electrode has been studied by means of in situ UV-Vis subtractive reflectance spectroscopy. An absorbency band around 245 nm, which was ascribed to the formation of an intermediate,· PHO2-, was observed in the electrocatalytic oxidation process. Accordingly, the electrocatalytic oxidation of hypophosphite might undergo a H abstraction of hypophosphite from the P-H bond to form the phosphoruscentred radical, · PHO2-, which is subsequently electrooxidized to the final product, phosphite.
1999, 10(10): 867-870
Abstract:
For the concentrated dispersions of epoxy resin prepared by phase inversion emulsification technique, the effects of solid content and temperature on the rheological behavior are studied. It is found that there exists reversible structural transition in concentrated dispersions subjected to shearing. The viscosity oscillation correlated with high viscoelasticity at lower stress is remarkable in highly concentrated dispersions. There exists storage modules overshot at higher stress during the dynamic stress time ramp test. This could provide some information on dynamics of structure changes during shear action. Besides, the effects of solid content and temperature on the relationship between tangent delta and frequency are essentially different.
For the concentrated dispersions of epoxy resin prepared by phase inversion emulsification technique, the effects of solid content and temperature on the rheological behavior are studied. It is found that there exists reversible structural transition in concentrated dispersions subjected to shearing. The viscosity oscillation correlated with high viscoelasticity at lower stress is remarkable in highly concentrated dispersions. There exists storage modules overshot at higher stress during the dynamic stress time ramp test. This could provide some information on dynamics of structure changes during shear action. Besides, the effects of solid content and temperature on the relationship between tangent delta and frequency are essentially different.
1999, 10(10): 871-872
Abstract:
Polystyrene/Poly(ethylene terephthlate) (PET) blends have been prepared by the heterogeneous free-radical polymerization of styrene within supercritical carbon dioxide-swollen PET substrates. Composition of the blends and the averaQ molecular weight of polystyrene in the blends can be controlled by equilibration time and reaction condition.
Polystyrene/Poly(ethylene terephthlate) (PET) blends have been prepared by the heterogeneous free-radical polymerization of styrene within supercritical carbon dioxide-swollen PET substrates. Composition of the blends and the averaQ molecular weight of polystyrene in the blends can be controlled by equilibration time and reaction condition.
1999, 10(10): 873-874
Abstract:
Constant-volume heat capacities of supercritical (SC) CO2, SC CO2-n-pentane, and SC CO2-n-heptane mixtures were determined at 308.15 K in the pressure range from 6 to 12 MPa. It was found that there is a maximum in each heat capacity vs pressure curve. Intermolecular interaction in the fluids was studied.
Constant-volume heat capacities of supercritical (SC) CO2, SC CO2-n-pentane, and SC CO2-n-heptane mixtures were determined at 308.15 K in the pressure range from 6 to 12 MPa. It was found that there is a maximum in each heat capacity vs pressure curve. Intermolecular interaction in the fluids was studied.
1999, 10(10): 875-878
Abstract:
The reaction of the trialkyl metals (R3M, R=Me, Et; M=Ga, In) with henzo[h]quinolin-10-ol] (HO-BQ) in a 1:1 molar ratio gave intramolecular N coordinated complexes R2M-O-BQ (M=Ga, R=Me 1, Et 2) and (R2In-O-BQ)2 (M=In, R=Et 3,)in 80-90% yield. The molecular structures of complexes 1 and 3 have been established by X-ray crystallography.
The reaction of the trialkyl metals (R3M, R=Me, Et; M=Ga, In) with henzo[h]quinolin-10-ol] (HO-BQ) in a 1:1 molar ratio gave intramolecular N coordinated complexes R2M-O-BQ (M=Ga, R=Me 1, Et 2) and (R2In-O-BQ)2 (M=In, R=Et 3,)in 80-90% yield. The molecular structures of complexes 1 and 3 have been established by X-ray crystallography.
1999, 10(10): 879-880
Abstract:
The complex of rare earth with ciprofloxacin has been synthesized and characterized by means of x-ray single crystal diffraction. The structure features of the complex are decribed.
The complex of rare earth with ciprofloxacin has been synthesized and characterized by means of x-ray single crystal diffraction. The structure features of the complex are decribed.
1999, 10(10): 881-884
Abstract:
Three new asymmetrical ruthenium (Ⅱ) complexes: [Ru(phen)2{phen-NHCO(CH2)4Br}](PF6)2, [Ru(phen)2{phen-NHCO(CH2)5Br}](PF6)2 and [Ru(phen)2{phen-NHCO(CH2)10Br}](PF6)2 were synthesized, which were confirmed by the technique of FT-IR, 1H NMR and ESI-MS. The electrochemical and fluorescent properties of three Ru (Ⅱ) complexes were investigated with cyclic voltammetry and fluorometry.
Three new asymmetrical ruthenium (Ⅱ) complexes: [Ru(phen)2{phen-NHCO(CH2)4Br}](PF6)2, [Ru(phen)2{phen-NHCO(CH2)5Br}](PF6)2 and [Ru(phen)2{phen-NHCO(CH2)10Br}](PF6)2 were synthesized, which were confirmed by the technique of FT-IR, 1H NMR and ESI-MS. The electrochemical and fluorescent properties of three Ru (Ⅱ) complexes were investigated with cyclic voltammetry and fluorometry.
1999, 10(10): 885-888
Abstract:
Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface of honeycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM were performed and it has been proved that the zeolite ZSM-5 was grown on the surface of the cordierite homogeneously. NO decomposition on the Cu exchanged ZSM-5/cordierite monolith catalysts was also studied. It was found that the monolith catalysts have a fine initial activity at 673K and GHSV of 10,000h-1. Such method should be a good way to make auto exhaust converter with monolith catalyst for NOx removal.
Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface of honeycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM were performed and it has been proved that the zeolite ZSM-5 was grown on the surface of the cordierite homogeneously. NO decomposition on the Cu exchanged ZSM-5/cordierite monolith catalysts was also studied. It was found that the monolith catalysts have a fine initial activity at 673K and GHSV of 10,000h-1. Such method should be a good way to make auto exhaust converter with monolith catalyst for NOx removal.
