2000 Volume 11 Issue 8

Asymmetric Reformatsky Reaction Induced by Dipeptides
Zhong Yi WANG , Jie SHEN , Chang Sheng JIANG , Tian Pa YOU
2000, 11(8): 659-662
[Abstract](174) [FullText HTML] [PDF 155KB](0)
For the first time, synthetic dipeptides were applied to the catalysis of asymmetric Reformatsky reaction. Review in this domain & factors influencing enantioselectivity were discussed.
Synthesis of the C5-C10 Segment of Taurospongin A
Guang Rong ZHENG , Wei LU , Jun Chao CAI
2000, 11(8): 663-664
[Abstract](162) [FullText HTML] [PDF 84KB](0)
Stereoselective synthesis of C5-C10 segment 3 of taurospongin A (1) has been developed successfully from L-(-)-malic acid.
Synthesis of 2-methoxy-6-oxo-1,4,2-diazaphosphorinane-2-oxide, A New Potential Antitumor Phosphorus Heterocycle Compound
Liang XU , Guang Rong ZHENG , Min XIA , Jun Chao CAI
2000, 11(8): 665-666
[Abstract](178) [FullText HTML] [PDF 82KB](0)
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.
Synthesis of Some Novel 2,6-Dimethoxyhydroquinone-3-mercaptoacetyl-peptide Conjugates as Potential Antitumor Agents
Yu Fei SONG , Pin YANG , Leung SHEH
2000, 11(8): 667-670
[Abstract](178) [FullText HTML] [PDF 174KB](0)
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.
Preparation of AChE Inhibitors From Jujubogenin
Yu ZHAO , Yuan Ling KU , Shoei Sheng LEE
2000, 11(8): 671-674
[Abstract](183) [FullText HTML] [PDF 173KB](0)
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.
Synthesis and Characterization of Fully-Functionalized Polysilanes for Photorefractive Materials
Hong Ding TANG , Jin Gui QIN
2000, 11(8): 675-676
[Abstract](177) [FullText HTML] [PDF 93KB](0)
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).
Total Synthesis of the Natural Product-Pinosylvin and its Analog
Zhi Song PIAO , Lin WANG , Zhi Zhong ZHAO
2000, 11(8): 677-678
[Abstract](169) [FullText HTML] [PDF 88KB](1)
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.
A Novel Photoproduct of Uracil in Phosphate-Buffered Saline
Feng LIN
2000, 11(8): 679-680
[Abstract](166) [FullText HTML] [PDF 82KB](0)
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.
Polyaniline Formed in Alkaline Solution-A New Luminous Material
Nian Bing LI , Sheng Tao ZHANG , Pei Dao DING
2000, 11(8): 681-684
[Abstract](190) [FullText HTML] [PDF 154KB](0)
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.
A New Organic Up-conversion Laser Dye HEASPS
Yan REN , Guang Yong ZHOU , Chun WANG , Xiao Mei WANG , Zhi LIU , Xian ZHAO , Wen Tao YU , Min Hua JIANG
2000, 11(8): 685-688
[Abstract](179) [FullText HTML] [PDF 143KB](0)
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.
Novel Product and Its Derivatives from the Reaction of Lappaconitine with HIO4
Qiao Hong CHEN , Feng Peng WANG , Kai Bai YU
2000, 11(8): 689-692
[Abstract](192) [FullText HTML] [PDF 179KB](2)
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%).
Substituents Effect on the Optical Properties of Benzonitrile and Oligobenzonitriles
Ting Jun HOU , You Yong LI , Yuan Kang HE , Hui Ying CHEN , Xiao Jie XU
2000, 11(8): 693-696
[Abstract](185) [FullText HTML] [PDF 161KB](2)
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.
Two New Oleanane Saponins from Anemone anhuiensis
Qing Wen ZHANG , Wen Cai YE , Chun Tao CHE , Shou Xun ZHAO
2000, 11(8): 697-700
[Abstract](180) [FullText HTML] [PDF 138KB](0)
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.
Pyrohyperforin, A New Prenylated Phloroglucinol from Hypericum perforatum
Ming De SHAN , Li Hong HU , Zhong Liang CHEN
2000, 11(8): 701-704
[Abstract](189) [FullText HTML] [PDF 110KB](1)
Pyrohyperforin, a new prenylated phloroglucinol was isolated from Hypericum perforatum, its structure was established on the basis of spectral data.
New Bibenzyl and Phenanthrenedione from Dendrobium densiflorum
Cheng Qi FAN , Wei Min ZHAO , Guo Wei QIN
2000, 11(8): 705-706
[Abstract](186) [FullText HTML] [PDF 88KB](0)
A new bibenzyl 1 and a new phenanthrenedione 2 were identified from the stems of Dendrobium densiflorum (Orchidaceae).
Dasycarine, a New Quinoline Alkaloid from Dictamnus dasycarpus
Jin CHEN , Jing Sheng TANG , Jun TIAN , You Ping WANG , Feng E WU
2000, 11(8): 707-708
[Abstract](191) [FullText HTML] [PDF 87KB](2)
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.
A New Monoterpene Glycoside from Swertia punicea
Xin MING , Ming Hua QIU , Rui Lin NIE , Guo Lin ZHANG
2000, 11(8): 709-710
[Abstract](176) [FullText HTML] [PDF 87KB](0)
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 Ursene Type Triterpenoid from Crepis napifera
Shao Hua WU , Xiao Dong LUO , Yun Bao MA , Da Gang WU
2000, 11(8): 711-712
[Abstract](177) [FullText HTML] [PDF 82KB](0)
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.
Strong Room-Temperature Photoluminescence from the Novel Adduct of C60 with Aliphatic Amines
Jin Li QIAO , Qiao Juan GONG , Chuan DONG , Wei Jun JIN
2000, 11(8): 713-716
[Abstract](177) [FullText HTML] [PDF 165KB](0)
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.
Chiral Discrimination in N-(O, O-dialkyl) phosphoamino Acid Monolayers at the Air-water Interface
Ning XU , Zhou ZHOU , Hong Mei WANG , Chang Hui DENG , Yan Mei LI , Yu Fen ZHAO , Ling Xuan WANG , Tian Kai LI
2000, 11(8): 717-718
[Abstract](173) [FullText HTML] [PDF 89KB](0)
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.
Enhanced Electron Transfer for Hemoglobin in 2C12N+PVS- Composite Films Modified on Pyrolytic Graphite Electrodes
Yu Jiao HU , Ying Lin ZHOU , Yong Huai ZENG , Nai Fei HU
2000, 11(8): 719-720
[Abstract](168) [FullText HTML] [PDF 101KB](0)
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.
Kinetic Study on Horseradish Peroxidase Interacting with Cyclodextrin
Jian Bo CHEN , Chun Gu XIA , Shu Ben LI
2000, 11(8): 721-724
[Abstract](170) [FullText HTML] [PDF 166KB](0)
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.
La3+ Transmembrane Research in Guinea Pig Ventricular Cells by Fura-2 Fluorescence
Rong CHEN , Pin YANG , Chun Ying WEI
2000, 11(8): 725-726
[Abstract](171) [FullText HTML] [PDF 105KB](0)
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.
Is HOMO Energy Level a Good Parameter to Characterize Antioxidant Activity
Hong Yu ZHANG , De Zhan CHEN
2000, 11(8): 727-730
[Abstract](182) [FullText HTML] [PDF 197KB](0)
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.
Enantioseparation of some Racemic Compounds on Cellulose Tris (3,5-dimethylphenylcarbamate) Chiral Stationary Phase
Xiao Qian HAN , Hui Tao LIU , Jin Zhang GAO , Jing Guo HOU , Chong Yang LI , Guo Hu ZHAO
2000, 11(8): 731-734
[Abstract](169) [FullText HTML] [PDF 132KB](0)
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.
Poly (ethylene oxide) Solubilization in Reverse Microemulsion:Conductivity and UV-Vis Spectra Studies
Zhen Shan HOU , Zhi Ping LI , Han Qing WANG
2000, 11(8): 735-738
[Abstract](173) [FullText HTML] [PDF 166KB](0)
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.
Dielectric Behavior of Middle Phase Microemulsion
Jian Ping LEI , Ying LI , Kong Shuang ZHAO
2000, 11(8): 739-742
[Abstract](182) [FullText HTML] [PDF 154KB](0)
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.
Pretreatment of Polymer-Supported Pd-Co and Its Catalytic Activity
Yan GAO , Shi Jian LIAO , Fu Dong WANG , Yue GAO , Xi Gao JIAN
2000, 11(8): 743-744
[Abstract](171) [FullText HTML] [PDF 104KB](0)
Various pretreatments of poly (N-vinyl-2-pyrrolidone) (PVP) protected palladium-cobalt system result in different catalytic activities in the hydrodechlorination of chlorobenzene.
The Synthesis of Isotactic Polypropylene with Spherical Morphology via Supported Metallocene Catalyst
Han HONG , Wei Dong YAN , Ming Ge ZHANG , Nai ZHOU , Da Wei HE , You Liang HU
2000, 11(8): 745-746
[Abstract](172) [FullText HTML] [PDF 197KB](0)
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.
Chemical Bond Parameters in Sr3MRhO6 (M=Rare earth)
Zhi Jian WU , Si Yuan ZHANG
2000, 11(8): 747-748
[Abstract](171) [FullText HTML] [PDF 91KB](0)
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.
Crystal Structure and Magnetic Studies of a New Nitronyl Nitroxide Compound
Liang DING , De Qing ZHANG , Bin ZHANG , Dao Ben ZHU
2000, 11(8): 749-752
[Abstract](171) [FullText HTML] [PDF 170KB](0)
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.
Address:Zhongguancun North First Street 2,100190 Beijing, PR China Tel: +86-010-82449177-888
Powered By info@rhhz.net