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2000 Volume 11 Issue 8
2000, 11(8): 659-662
Abstract:
For the first time, synthetic dipeptides were applied to the catalysis of asymmetric Reformatsky reaction. Review in this domain & factors influencing enantioselectivity were discussed.
For the first time, synthetic dipeptides were applied to the catalysis of asymmetric Reformatsky reaction. Review in this domain & factors influencing enantioselectivity were discussed.
2000, 11(8): 663-664
Abstract:
Stereoselective synthesis of C5-C10 segment 3 of taurospongin A (1) has been developed successfully from L-(-)-malic acid.
Stereoselective synthesis of C5-C10 segment 3 of taurospongin A (1) has been developed successfully from L-(-)-malic acid.
2000, 11(8): 665-666
Abstract:
2-methoxy-6-oxo-1,4,2-diazaphosphorinane-2-oxide 8, phosphorus counterpart of 2,6-dioxopiperazine, was synthesized as antitumor agent. The new phosphorus heterocycle compound 8 is the key intermediate in the synthesis of phosphorus counterpart of bisdioxopiperazine.
2-methoxy-6-oxo-1,4,2-diazaphosphorinane-2-oxide 8, phosphorus counterpart of 2,6-dioxopiperazine, was synthesized as antitumor agent. The new phosphorus heterocycle compound 8 is the key intermediate in the synthesis of phosphorus counterpart of bisdioxopiperazine.
2000, 11(8): 667-670
Abstract:
This paper reports an ongoing study of the use of short chain peptides as carriers of a potential antitumor agents: 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). Three new peptide-DMQ-MA conjugates: DMQ-MA-arg-arg-ome, DMQ-MA-lys(cbz)-arg-ome, DMQ-MA-lys(cbz)-arg-arg-ome were synthesized by coupling protected amino acids in solution and the next conjugation was achieved by reacting with pentafluorophenyl ester of DMQ-MA in DMF, and further study on their ability to inhibit human pulmonary adenocarcinoma cell line (PC-9 cells) and oral epidermoid carcinoma cell line (KB) are investigating.
This paper reports an ongoing study of the use of short chain peptides as carriers of a potential antitumor agents: 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). Three new peptide-DMQ-MA conjugates: DMQ-MA-arg-arg-ome, DMQ-MA-lys(cbz)-arg-ome, DMQ-MA-lys(cbz)-arg-arg-ome were synthesized by coupling protected amino acids in solution and the next conjugation was achieved by reacting with pentafluorophenyl ester of DMQ-MA in DMF, and further study on their ability to inhibit human pulmonary adenocarcinoma cell line (PC-9 cells) and oral epidermoid carcinoma cell line (KB) are investigating.
2000, 11(8): 671-674
Abstract:
A dammarane derivative dihydrojujubogenin-2-en-1-one, which possesses a skeleton and pharmacophore partially similar to those of Territrem B, a potent AChE inhibitor, was synthesized via three different paths. The anti-AChE activity of this compound and related analogue was measured.
A dammarane derivative dihydrojujubogenin-2-en-1-one, which possesses a skeleton and pharmacophore partially similar to those of Territrem B, a potent AChE inhibitor, was synthesized via three different paths. The anti-AChE activity of this compound and related analogue was measured.
2000, 11(8): 675-676
Abstract:
Hydrogen-containing polysilanes and chromophore-containing polysilanes are prepared by traditional Wurtz coupling and subsequent hydrosilylation. They are characterized by 1H-NMR, FT-IR, UV/VIS spectroscopies, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC).
Hydrogen-containing polysilanes and chromophore-containing polysilanes are prepared by traditional Wurtz coupling and subsequent hydrosilylation. They are characterized by 1H-NMR, FT-IR, UV/VIS spectroscopies, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC).
2000, 11(8): 677-678
Abstract:
We synthesised a natural product (10), isolated from G.parvifolium, and its analog. The synthetic product was characterized by elemental analysis and 1H-NMR in comparision with the corresponding natural product.
We synthesised a natural product (10), isolated from G.parvifolium, and its analog. The synthetic product was characterized by elemental analysis and 1H-NMR in comparision with the corresponding natural product.
2000, 11(8): 679-680
Abstract:
The photolysis of uracil in phosphate-buffered saline (PBS, pH 8.0) under the irradiation of medium pressure mercury lamp (MPML) leads to the production of a novel compound C4H5N2O6P. The composition and structure of the compound has been identified by elemental analysis, EI-MS, UV, IR, 1H, 13C, 31P-NMR.
The photolysis of uracil in phosphate-buffered saline (PBS, pH 8.0) under the irradiation of medium pressure mercury lamp (MPML) leads to the production of a novel compound C4H5N2O6P. The composition and structure of the compound has been identified by elemental analysis, EI-MS, UV, IR, 1H, 13C, 31P-NMR.
2000, 11(8): 681-684
Abstract:
Electropolymerization of aniline in KOH solution and properties of the polymer are studied by using in situ reflex ellipsometry, cyclic voltammetry and fluorescence spectroscopic method. The change patterns of ellipsometric parameters and the thickness of film in the process of electropolymerization are investigated. The complex refractive indices and the fluorescence spectra of PAN indicate that the PAN is a new kind of luminous material.
Electropolymerization of aniline in KOH solution and properties of the polymer are studied by using in situ reflex ellipsometry, cyclic voltammetry and fluorescence spectroscopic method. The change patterns of ellipsometric parameters and the thickness of film in the process of electropolymerization are investigated. The complex refractive indices and the fluorescence spectra of PAN indicate that the PAN is a new kind of luminous material.
2000, 11(8): 685-688
Abstract:
A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl-pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.
A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl-pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.
2000, 11(8): 689-692
Abstract:
Treatment of lappaconitine 1 with HIO4 at room temperature afforded 2 in 41% yield, to which Br2-HOAc solution was added and allowed to stand at room temperature for 2 days to give 3 (13%) and 4 (31%).
Treatment of lappaconitine 1 with HIO4 at room temperature afforded 2 in 41% yield, to which Br2-HOAc solution was added and allowed to stand at room temperature for 2 days to give 3 (13%) and 4 (31%).
2000, 11(8): 693-696
Abstract:
The semiempirical calculations were performed to discuss the effects of different substituents on the optical properties of a series of substituted benzonitriles and their corresponding oligomers. The substituents located in para, meta and ortho-position of the benzenoid ring involve a large range of δ-π electron-donor-acceptor capability. Theoretical analysis shows that the optical property is affected by the steric and electronic characteristics of the substituents on the benzenoid ring, moreover, the third-order polarizability regularly varies with the polymerization degrees.
The semiempirical calculations were performed to discuss the effects of different substituents on the optical properties of a series of substituted benzonitriles and their corresponding oligomers. The substituents located in para, meta and ortho-position of the benzenoid ring involve a large range of δ-π electron-donor-acceptor capability. Theoretical analysis shows that the optical property is affected by the steric and electronic characteristics of the substituents on the benzenoid ring, moreover, the third-order polarizability regularly varies with the polymerization degrees.
2000, 11(8): 697-700
Abstract:
Two new oleanane triterpene saponins, named as anhuienside C (1) and D (2), were isolated from the rhizomes of Anemone anhuiensis (Ranunculaceae). The structures of the new compounds were elucidated as 3-O-α-L-rhamnopyranosyl (1→2)-β-D-xylopyranosyl oleanolic acid 28-O-b-D-glucopyranosyl (1→6)-β-D-glucopyranosyl ester (1) and 3-O-β-D-xylopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranosyl (1→6)-β-D-gluco-pyranosyl ester (2), respectively.
Two new oleanane triterpene saponins, named as anhuienside C (1) and D (2), were isolated from the rhizomes of Anemone anhuiensis (Ranunculaceae). The structures of the new compounds were elucidated as 3-O-α-L-rhamnopyranosyl (1→2)-β-D-xylopyranosyl oleanolic acid 28-O-b-D-glucopyranosyl (1→6)-β-D-glucopyranosyl ester (1) and 3-O-β-D-xylopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranosyl (1→6)-β-D-gluco-pyranosyl ester (2), respectively.
2000, 11(8): 701-704
Abstract:
Pyrohyperforin, a new prenylated phloroglucinol was isolated from Hypericum perforatum, its structure was established on the basis of spectral data.
Pyrohyperforin, a new prenylated phloroglucinol was isolated from Hypericum perforatum, its structure was established on the basis of spectral data.
2000, 11(8): 705-706
Abstract:
A new bibenzyl 1 and a new phenanthrenedione 2 were identified from the stems of Dendrobium densiflorum (Orchidaceae).
A new bibenzyl 1 and a new phenanthrenedione 2 were identified from the stems of Dendrobium densiflorum (Orchidaceae).
2000, 11(8): 707-708
Abstract:
Dasycarine, a new quinoline alkaloid along with five known compounds, dictamine, dihydroobacunone, obacunone, fraxinellone and β-sitosterol, were isolated from Dictamnus dasycarpus. The structure of dasycarine was identified as 4,5,8-trimethoxyl-3-(3-methyl-2-butenyl)-2-quinone by 1D and 2D NMR techniques.
Dasycarine, a new quinoline alkaloid along with five known compounds, dictamine, dihydroobacunone, obacunone, fraxinellone and β-sitosterol, were isolated from Dictamnus dasycarpus. The structure of dasycarine was identified as 4,5,8-trimethoxyl-3-(3-methyl-2-butenyl)-2-quinone by 1D and 2D NMR techniques.
2000, 11(8): 709-710
Abstract:
A new monoterpene glycoside, 2,6-dimethyl-2E,6E-octadienoic acid 1,6'-lactone 8-β-D-glucopyranoside, was isolated from Swertia punicea, accompanying with six known compounds 1-O-primeverosyl-3,7-dimethoxy-8-hydroxyxanthone, 1-O-primeverosyl-3,7,8-tri-methoxyxan-thone, epi-eustomoside, 1-hydroxy-3,7,8-trimethoxyxanthone, 1,8-dihydroxy-3,7-dimethoxy xanthone and isovitexine. Their structures were elucidated based on spectral evidence.
A new monoterpene glycoside, 2,6-dimethyl-2E,6E-octadienoic acid 1,6'-lactone 8-β-D-glucopyranoside, was isolated from Swertia punicea, accompanying with six known compounds 1-O-primeverosyl-3,7-dimethoxy-8-hydroxyxanthone, 1-O-primeverosyl-3,7,8-tri-methoxyxan-thone, epi-eustomoside, 1-hydroxy-3,7,8-trimethoxyxanthone, 1,8-dihydroxy-3,7-dimethoxy xanthone and isovitexine. Their structures were elucidated based on spectral evidence.
2000, 11(8): 711-712
Abstract:
A new triterpenoid, urs-20-en-3β-acetoxy-22α-ol, and three known compounds 3β-acetoxy-amyrin, 3β-acetoxy-lupeol, lupeol were isolated from the leaves of Crepis napifera (Franch.) Babc. Their structures were determined by means of spectroscopic studies.
A new triterpenoid, urs-20-en-3β-acetoxy-22α-ol, and three known compounds 3β-acetoxy-amyrin, 3β-acetoxy-lupeol, lupeol were isolated from the leaves of Crepis napifera (Franch.) Babc. Their structures were determined by means of spectroscopic studies.
2000, 11(8): 713-716
Abstract:
Strong room-temperature photoluminescence from the adducts of C60 reacting with five different aliphatic amines, namely propylethylamine (PPA), n-butyl amine (BTA), n-heptylamine (HPA) and dodecylamine (DDA) and diethylamine (DEA), was firstly found from their toluene solution at relatively shorter wavelength around 519 nm.The fluorescence intensity has a good correlation with the length of n-alkyl group chain, the steric position and concentration of different amines and setting of solution as well as the UV-radiation. Their fluorescence quenching by concentration and by aromatic electron-donor N,N-dimethylaniline (DMA) were first investigated and determined.
Strong room-temperature photoluminescence from the adducts of C60 reacting with five different aliphatic amines, namely propylethylamine (PPA), n-butyl amine (BTA), n-heptylamine (HPA) and dodecylamine (DDA) and diethylamine (DEA), was firstly found from their toluene solution at relatively shorter wavelength around 519 nm.The fluorescence intensity has a good correlation with the length of n-alkyl group chain, the steric position and concentration of different amines and setting of solution as well as the UV-radiation. Their fluorescence quenching by concentration and by aromatic electron-donor N,N-dimethylaniline (DMA) were first investigated and determined.
2000, 11(8): 717-718
Abstract:
In this paper, chiral discrimination in N-(O, O-dialkyl) phosphoamino acid monolayers at the air/water interface was studied and it was revealed that the D:L=1:1 racemic monolayer of N-(O, O-dihexadecyl) phosphoalanine is packed more densely in solid phase while shows a higher LE to LC transition pressure than the enantiomeric ones.
In this paper, chiral discrimination in N-(O, O-dialkyl) phosphoamino acid monolayers at the air/water interface was studied and it was revealed that the D:L=1:1 racemic monolayer of N-(O, O-dihexadecyl) phosphoalanine is packed more densely in solid phase while shows a higher LE to LC transition pressure than the enantiomeric ones.
2000, 11(8): 719-720
Abstract:
Stable thin films made from polyionic complex 2C12N+PVS- with incorporated Hb on PG electrodes were characterized by electrochemistry. The electron transfer between Hb and PG electrodes was greatly facilitated in microenvironment of 2C12N+PVS- films. The Hb-2C12N+PVS- films could be used to catalytically reduce trichloroacetic acid.
Stable thin films made from polyionic complex 2C12N+PVS- with incorporated Hb on PG electrodes were characterized by electrochemistry. The electron transfer between Hb and PG electrodes was greatly facilitated in microenvironment of 2C12N+PVS- films. The Hb-2C12N+PVS- films could be used to catalytically reduce trichloroacetic acid.
2000, 11(8): 721-724
Abstract:
The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of β-cyclodextrin. During this course, β-cyclodextrin played a role of stabilizing the intermediates of HRP. The results have been investigated using spectra and calculation.
The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of β-cyclodextrin. During this course, β-cyclodextrin played a role of stabilizing the intermediates of HRP. The results have been investigated using spectra and calculation.
2000, 11(8): 725-726
Abstract:
Binding of La3+ to Fura-2 can change 340/380 nm fluorescence intensity ratio. Whether La3+ cross ventricular cell membrane was detected by this fluorescent probe technique. Fura-2 loaded isolated guinea pig ventricular cells were exposed to 0.01-0.1mM extracellular Lanthanum ion concentration, 340nm/380 nm fluorescence ratio was not changed. Using calcium channel agonist BAY K8644, KCL (35mM) depolarization to open the voltage-dependent calcium channel (VDCC); Adrenoceptor agonist to excite adrenoceptor, 340/380 ratio was not changed, suggesting that La3+ can not enter guinea pig ventricular cells in this case.
Binding of La3+ to Fura-2 can change 340/380 nm fluorescence intensity ratio. Whether La3+ cross ventricular cell membrane was detected by this fluorescent probe technique. Fura-2 loaded isolated guinea pig ventricular cells were exposed to 0.01-0.1mM extracellular Lanthanum ion concentration, 340nm/380 nm fluorescence ratio was not changed. Using calcium channel agonist BAY K8644, KCL (35mM) depolarization to open the voltage-dependent calcium channel (VDCC); Adrenoceptor agonist to excite adrenoceptor, 340/380 ratio was not changed, suggesting that La3+ can not enter guinea pig ventricular cells in this case.
2000, 11(8): 727-730
Abstract:
Semiempirical quantum chemical method AMI was employed to calculate the highest occupied molecular orbital (HOMO) energy levels (EHOMO) for various types of antioxidants. It was verified that the correlation between logarithm of free radical scavenging rate constants (lgks) and EHOMO substantially arises from the correlation between EHOMO and O-H bond dissociation energies (BDE) of antioxidants. Furthermore, EHOMO were poorly correlated with the logarithm of relative free radical scavenging rate constants (lgk3/k1) for various types of antioxidants that possess complex structures (r=0.5602). So in a broad sense, EHOMO was not an appropriate parameter to characterize the free radical scavenging activity of antioxidants.
Semiempirical quantum chemical method AMI was employed to calculate the highest occupied molecular orbital (HOMO) energy levels (EHOMO) for various types of antioxidants. It was verified that the correlation between logarithm of free radical scavenging rate constants (lgks) and EHOMO substantially arises from the correlation between EHOMO and O-H bond dissociation energies (BDE) of antioxidants. Furthermore, EHOMO were poorly correlated with the logarithm of relative free radical scavenging rate constants (lgk3/k1) for various types of antioxidants that possess complex structures (r=0.5602). So in a broad sense, EHOMO was not an appropriate parameter to characterize the free radical scavenging activity of antioxidants.
2000, 11(8): 731-734
Abstract:
Seven chiral compounds were resolved on cellulose tris (3,5-dimethylphenylcarbamate) chiral stationary phase (CDMPC-CSP) using n-hexane/alcohol as mobile phase. Solvent strength and structural characteristics of the compounds effecting on the retention and resolution were discussed. Satisfactory separation was obtained.
Seven chiral compounds were resolved on cellulose tris (3,5-dimethylphenylcarbamate) chiral stationary phase (CDMPC-CSP) using n-hexane/alcohol as mobile phase. Solvent strength and structural characteristics of the compounds effecting on the retention and resolution were discussed. Satisfactory separation was obtained.
2000, 11(8): 735-738
Abstract:
The effect of poly (ethylene oxide) (PEO) on the w/o microemulsion is studied. The addition of PEO induces a decrease of attractive interaction between droplets in reverse microemulsion. Due to the absence of interaction between cationic surfactant and neutral polymer, the polymer molecules are forced into the interior of water core, avoiding the interfacial region.
The effect of poly (ethylene oxide) (PEO) on the w/o microemulsion is studied. The addition of PEO induces a decrease of attractive interaction between droplets in reverse microemulsion. Due to the absence of interaction between cationic surfactant and neutral polymer, the polymer molecules are forced into the interior of water core, avoiding the interfacial region.
2000, 11(8): 739-742
Abstract:
Dielectric measurements were performed on middle phase microemulsions composed of sodium dodecylsulfate(SDS), cetyltrimethylammonium bromide(CTAB), n-butanol, n-heptane and brine. Distinct and unique dielectric behavior, with characteristic frequency dependence regularity on the salinity of the microemulsions, was observed in the low-frequency range from 10-103Hz. It can be considered to be an interfacial polarization mechanism.
Dielectric measurements were performed on middle phase microemulsions composed of sodium dodecylsulfate(SDS), cetyltrimethylammonium bromide(CTAB), n-butanol, n-heptane and brine. Distinct and unique dielectric behavior, with characteristic frequency dependence regularity on the salinity of the microemulsions, was observed in the low-frequency range from 10-103Hz. It can be considered to be an interfacial polarization mechanism.
2000, 11(8): 743-744
Abstract:
Various pretreatments of poly (N-vinyl-2-pyrrolidone) (PVP) protected palladium-cobalt system result in different catalytic activities in the hydrodechlorination of chlorobenzene.
Various pretreatments of poly (N-vinyl-2-pyrrolidone) (PVP) protected palladium-cobalt system result in different catalytic activities in the hydrodechlorination of chlorobenzene.
2000, 11(8): 745-746
Abstract:
Polymerization or propylene was carried out under bulk process at 70℃ using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as co-catalyst. The morphology of the products was studied by SEM. It was found the property of the carriers gave great effect on the fine structure of the products as well as the apperance.
Polymerization or propylene was carried out under bulk process at 70℃ using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as co-catalyst. The morphology of the products was studied by SEM. It was found the property of the carriers gave great effect on the fine structure of the products as well as the apperance.
2000, 11(8): 747-748
Abstract:
Chemical bond parameters, that is, bond covalency, bond valence, macroscopic linear susceptibility, and oxidation states of elements in Sr3MRhO6 (M=Sm, Eu, Tb, Dy, Ho, Er, Yb) have been calculated. The results indicate that the bond covalency of M-O decreases sharply with the decrease of ionic radius of M3+ from Sm to Yb, while no obvious trend has been found for Rh-O and Sr-O bonds. The global instability index indicates that the crystal structures of Sr3MrhO6 (M=Sm, Eu, Tb, Dy, Ho) have strained bonds.
Chemical bond parameters, that is, bond covalency, bond valence, macroscopic linear susceptibility, and oxidation states of elements in Sr3MRhO6 (M=Sm, Eu, Tb, Dy, Ho, Er, Yb) have been calculated. The results indicate that the bond covalency of M-O decreases sharply with the decrease of ionic radius of M3+ from Sm to Yb, while no obvious trend has been found for Rh-O and Sr-O bonds. The global instability index indicates that the crystal structures of Sr3MrhO6 (M=Sm, Eu, Tb, Dy, Ho) have strained bonds.
2000, 11(8): 749-752
Abstract:
Compound 1 was first synthesized and characterized. Its crystal structure and magnetic property were determined and investigated. Discussion about the molecule packing in crystal and the macroscopic magnetism was also presented, in combination with computing study of the spatial distribution over the molecule.
Compound 1 was first synthesized and characterized. Its crystal structure and magnetic property were determined and investigated. Discussion about the molecule packing in crystal and the macroscopic magnetism was also presented, in combination with computing study of the spatial distribution over the molecule.
