1993 Volume 4 Issue 7

REGIOSELECTIVE O-ALKYLATION OF MYO-INOSITOL DERIV ATIVES WITH ALKYL HALIDES UNDER S-L PHASE TRANSFER CATALYTIC CONDITIONS
Yi Xiang DING , Jing SHEN , Shun Fu ZHOU
1993, 4(7): 565-566
[Abstract](159) [FullText HTML] [PDF 104KB](0)
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A convenient synthetic approach leading to protected inositol was described based on regioselective O-alkylation using alkyl halide under solid-liquid PTC condition
A FACILE SYNTHESIS OF 1.2-BISPYRROLEETHYLENS
Qing Qi CHEN , Fang YAN , Jin Shi Ma , Sheng JIN
1993, 4(7): 567-568
[Abstract](153) [FullText HTML] [PDF 83KB](0)
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1.2-Bispyrroleethylenes can be easily syntnesized bv covpling pyrrolealdehyde using TiCl4/Zn as a catalyst.It was found that when the R group is COMe or CO2 Et, the product is a mixture of trans and cis isomers, and in the other cases, the products are pure trans isomers.
SYNTHETIC STUDIES ON 15-NOR-QINGHAOSU
Bin YE , Chun ZHANG , Yu Lin WU
1993, 4(7): 569-572
[Abstract](159) [FullText HTML] [PDF 125KB](0)
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Synthetic studies on 4-demethyl-qinghaosu involving preparation of key intermediate olefin 5 and its photooxygenation were described.Experiment showed that rearrangement product 4 during the photooxygenation.
The Reaction of α, β-epoxyketones with methoxymethylenetriphenylphosphorane, A New Approach to α-alkylsubstituted-γ-hydroxy-α, β-unsaturated aldehydes
Li Bing YU , Zhi Qin WANG
1993, 4(7): 573-576
[Abstract](145) [FullText HTML] [PDF 91KB](0)
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The reaction of α, β-epoxyketones with methoxymethylenetriphenyl-phosphorane provides a method for the preparation of α-alkylsubstituted γ-hydroxy-α, β-unsaturated aldehydes with one carbon homologation and retention of configuration.
CATALYTIC DEBROMINATION OF DIPHENYL BROMOMETHANE UNDER HETEROPHASE CONDITIONS USING POLYMERS WITH VIOLOGEN STRUCTURE
Fu Tian LIU , Xian Da Yu , Shu Ben LI
1993, 4(7): 577-580
[Abstract](160) [FullText HTML] [PDF 99KB](0)
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The debromination of diphenyl bromomethane (Ph2CHBr) using polymers with viologen structure as electron-transfer catalyst (ETC) afforded tetraphenylethane in good yields under heterophase conditions.
SYNTHESIS AND ANTITUMOR ACTIVITY OF PEPTIDYL-N1-HYDROXYMETHYL-5-FLUOROURACIL
Yi LUO , Ren Xi ZHUO , Chang Lie FAN
1993, 4(7): 581-582
[Abstract](153) [FullText HTML] [PDF 75KB](0)
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Six hydrophobic peptidyl and four amino acid (L-Val, L-Leu,L-Phe, L-Gly) derivatives of 5-fluorouracil (5-FU) were synthesized.The structure of these compounds were characterized by 1H-NMR, IR,UV spectra and elemental analysis.The antitumor activity was test-ed against EAC cells in vitro.
CAN TRICHLOROMETHANE SULFONYL BROMIDE BE USED AS AN ADDENDUM AS WELL AS A TELOGEN IN ITS ADDITION REACTION TO VINYLIDENE FLUORIDE?
Michael Yu ZHU , Susan Si Xun SUN , Yu Buang ZHANG , Xi Kui JIANG
1993, 4(7): 583-586
[Abstract](156) [FullText HTML] [PDF 179KB](0)
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CCl3SO2Br used as a "telogen" reacts with CH2=CF2 to give mainly the "mono-adduct" CCl3CH2CF2Br, together with very small amouats of CCl3CF2CH2Br, CCl2BrCH2CF2Br and the "di-adduct" CCl3 (CH2CF2)2Br.The result indicates that CCl3SO2Br can be used as an addendum in trichloromethyl-bromo-addition reactions to olefins.
PHOTOINDUCED CHARGE TRANSFER REACTION OF BENZOPHENONE WITH AMINE IN VESICLES
Wei Dong YANG , Miao Zhen LI , Er Jian WANG
1993, 4(7): 587-590
[Abstract](160) [FullText HTML] [PDF 170KB](0)
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Photoinduced charge transfer reaction of benzophenone (BP) with, amine was carried out in the vesicles of dicetyldimethylammonium bromide (DCDAB) over wide ranges of amine concentration (0.01~4.0M).Linear plots of φ-1 vs.[TEA]-1 at low concentration of amine (<0.02M) and Ø-1 vs.[TEA]-2 at high concentration were obtained.Kinetic data demonstrate that the electron transfer is promoted significantly by DCDAB vesicles and proton transfer becomes more efficient at high amlne concentrations, leading to a decrease of Kd/Kr and increase of Kh/Ke.The kinetic expressions of photoreaction of BP bound to DCDAB bilayer are developed.
AN IMPROVED METHOD FOR PREPARING 2-ALKOXY-5-FLUORO-3H-4-PYRIMIDONE
Chang Jun SUN , Zai Cheng CHEN , Yi MENG , Yi Gui WANG , Peng XUE , Jian Guo ZHANG , Gui Xiang CUI
1993, 4(7): 591-592
[Abstract](156) [FullText HTML] [PDF 78KB](0)
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In this paper, we report an improved method for preparing 2-alkoxy-5-fluoro-3H-4-pyrimidone from 2-chloro-5-fluoro-3H-4-pyrimidone and sodium alkoxide under normal pressure at reflux temperature.Some new compounds were synthesized in higher yield by this method.
A NOVEL CYCLODIMERIZATION OF α, β-UNSATURATED CARBONYL COMPOUNDS PROMOTED BY ANHYDROUS NdOL3-LITHIUM NAPHTHALIDE SYSTEM
Jian Chun BAO , Mei Zhi BEI , Jun LU , Jin Ju ZHANG , Qing Tao SONG
1993, 4(7): 593-596
[Abstract](156) [FullText HTML] [PDF 119KB](0)
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The anhydrous NdCla-LiNp (LiNp=Lithium uaphthalide) system has been fouud to cause a novel cyclodimerization of α, β-unsaturated ketoues to give cyclopentauol derivatives (1 and 2).A possible reaction mechanism was proposed.
SYNTHESIS OF ANALOGUES OF HUPERZINE A
Xu Chang HE , Zhao Ying WANG , Yun Long LI , Zhen Rong XU , Dong Lu BAI
1993, 4(7): 597-600
[Abstract](160) [FullText HTML] [PDF 202KB](0)
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A new Lycopodium alkaloid huperzine A (1) possesses a potent inhibitory activity of acetylcholinesterase.Six structurally simplified analogues of huperzine A, compound 6, 7, 8, 12,13 and 15, were prepared and the inhibitory activities were evaluated.
1, 1'-BIS (BENZYLSELENO) FERROCENE PLATINUM COMPLEX AS HYDROSlLYLATION CATALYST FOR OLEFINS
Jun Zhi YAO , Bing Shou TIAN , Yuan Yin CHEN
1993, 4(7): 601-602
[Abstract](729) [FullText HTML] [PDF 70KB](0)
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1, 1'——Bis (benzylseleno) ferrocene and its platinum complex were synthesized.It was found that the platinum complex was efficient catalyst for the hydrosilylation of olefins with triethoxysilane.
METHANE OXIDATIVE COUPLING OVER METAL OXYFLUORIDE CATALYSTS
Xiao Ping ZHOU , Wei De ZHANG , Hui Lin WAN , Khi Rui TSAI
1993, 4(7): 603-604
[Abstract](161) [FullText HTML] [PDF 103KB](0)
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The MOC reaction over ZrO2/LaF3, CeO2/LaF3 and ThO2/LaF3 catalysts indicated hat these catalysts had high activity and high C2 selectivity at low temperature.In the temperature range 480℃ to 650℃.The methane conversion was 24.4% to 30.8%and the C2 selectivity was 40.0% to 55.4%.The XRD characterization of the catalysts indicated that O2-.and F- exchang happened and LaOF was formed.
OLIGOPEPTIDES FROM THE ROOTS OF ASTER TATARICUS L.f.
Dong Liang CHEN , Yu SHAO , Yu Xin CUI , R.Hartman
1993, 4(7): 605-608
[Abstract](152) [FullText HTML] [PDF 126KB](0)
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Two new oligopeptides, Asterin A and B, have been isolated from the roots of Aster tataricus L.f., and their structures were elucidated on the basis of spectroscopic, chemical and enzymatic methods.
THE CHEMICAL STRUCTURE OF HYPODEMAPYRAZIN
Ying Hua LU , Ya Min CHEN , Xin Min WUN , Hong En WANG , Cun Shen MA , Rong Long ZHU , De Quan YU
1993, 4(7): 609-610
[Abstract](162) [FullText HTML] [PDF 64KB](0)
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A novel alkaloid named Hypodemapyrazine was isolated from the whole plant of a fern,Hypodematium sinense Iwatsuki.Its chemical structure has been elucidated to be a novel skeleton containing a hydro-pyrazine by means of UV, IR, 1H-NMR, 13C-NMR and HRMS spectroscopy.
DETECTION AND QUANTITATION OF TRACE ETHYL CARBAMATE IN ALCOLLOLIC BEVERAGES BY GC/GC AND GC/GC/MS
Shou Wei SUN , Ya Ping MA
1993, 4(7): 611-614
[Abstract](161) [FullText HTML] [PDF 125KB](2)
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Analytical difficulties encountered in the determination of ethyl carbamate, a known cancinogen, in a wide variety of wines and spirits have been overcome by specific, sensitive GC/GC and CC/CC/MS methods with a relatively shorter extractionprocedure.The lowest detection limits were estimated to be 0.1 and 0.01μg/L for GC/GC and GC/GC/MS respectively.The RSD of the GC/GC method was 2.5%.
EVALUATON OF MICROWAVE PLASMA TORCH FOR ATOMIC FLUORESCENCE SPECTROMETRY WITH AN ULTRASONIC NEBULIZATION SAMPLE INTRODUCTION SYSTEM
Yi Mu LI , Yi Xiang DUAN , Jun LIU , Qin Han JIN
1993, 4(7): 615-618
[Abstract](164) [FullText HTML] [PDF 122KB](0)
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In this paper, a new MPT (microwave plasma torch) device has been used as a atomizer for atomic fluorescence spectrometry.Spme elements, such as Zn, Cd, Hg, Pb, As, Co, Mg, Cu, Ag, Mn, Fe have been investigated in detail.
NMR MICROSCOPY OF γ-IRRADIATED cis 1,4-POLYBUTADIENE
Yi Min SHEN , Xin ZHAO , Lun FEI
1993, 4(7): 619-620
[Abstract](151) [FullText HTML] [PDF 82KB](0)
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NMR microscopy has received great attention from various fields of research, especially material science by its possibility to study materials directly without destruction.Although this technique is almost limited to the detection of fluids constricted in solid samples, such as water in biological systems, solvent diffused in a polymer material1 and liquid saturated rock systems2, the mechanical defects of high elastic rubbers have also been detected3 We are extending this technique to the direct study of the effect of γ-irradiation on cis 1, 4-polybutadiene (PB).This article deals with the investigation of radiation induced crosslinking of PB by NMR microscopy.
INSTABILITY AND (2×1) RECONSWUCTON OF Ge (001) SURFACE FROM SOLID-STAIE POTENTIALS
Hua Gen YU , Ji Yuan CHENG
1993, 4(7): 621-622
[Abstract](168) [FullText HTML] [PDF 81KB](0)
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An empirical potential energy function comprising two-and three-body terms, whose parameters have been determiaed from the properties of solid germanium,is used to study the (2×l) reconstruction of the Ge (001) surface.It is found that the formation of a dimer bond lowers the total energy by 0.73eV/atom, as compared to the surface atoms on the ideal Ge (001) surface.
OPTICAL EFFECTS OF ANION ADSORPTION ON SILVER SOL
Ling ZANG , Chun Yan LIU , Xin Min REN
1993, 4(7): 623-624
[Abstract](161) [FullText HTML] [PDF 95KB](0)
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The optical effects of anion adsorption on silver sol have been studied, It was found that the anion adsorption can make the absorption peak of pure silver sol shifting to longer vevelenngth, which is attributed to the reduction of the free electron density in the surface layer of the silver particle.
SERS CHARACTERIZATION OF ADSORBED WATER AT VERY NEGATIVE POTENTIALS
Zhong Qun TIAN , Bing Wei MAO
1993, 4(7): 625-626
[Abstract](154) [FullText HTML] [PDF 87KB](0)
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Surface enhanced Raman scattering of water adsorbed at silver electrodes in very negative potential region was first observed and a simple model related to the adsorption configuration is proposed.
Effect of Irradiation on Crystallinity and Mechanical Properties of Ultrahigh-Molecular-Weight Polyethylene
Yong ZHAO , Yun Xia LUO , Bing Zheng JIANG
1993, 4(7): 627-630
[Abstract](168) [FullText HTML] [PDF 118KB](0)
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Ultrahigh-molecular-weight polyethylene (UHlMWPE) has been irradiated (0-40 Mrad) with a Co60 source at room temperature under vacuum.Their crystallinity has been investigated by DSC and SAXS A significant increase of heat of fusion can be seen at low irradiation doses, which is attributed to crystallization caused by chain scission during the process of irradiation.It is also observed that thickness of lamellae changes with irradiation dose.Young's modulus has been improved significantly after irradiation at low doses.
LOW ENERGY PATHS AND REORIENTATION OF SIDE-GROUPS OF POLYMERS DURING CONFORMATIONAL STATE TRANSITION
Xiao Zhen YANG , Li Ling HE , Bao Zhu AN , De Zhu MA
1993, 4(7): 631-634
[Abstract](152) [FullText HTML] [PDF 194KB](0)
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The conformational state transition of polymer chains relates to crystallization processes, migration of the chains in solution, fluctuation of the end-to-end distance of random coils, and the relaxation and phase transitions of polymers.A description of the conformational state transition requires questions about; 1) how many stable conformational states for a specific σ bond; 2) the barriers between the states; 3) the mechanism of the conformational transition; 4) any cooperative behavior during the transition.
MOLECULAR DYNAMICS SIMULATION ON VIERATIONAL SPECTROSCOPIC FEATURES OF HYDROGEN BONDS IN CRYSTALLINE POLYMERS
Xiao Zhen YANG , Shaw Ling HSU
1993, 4(7): 635-638
[Abstract](158) [FullText HTML] [PDF 163KB](0)
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Introduction The molecular dynamics simulation technique has recently proved to be a suitable alternative approach for simulation of vibrational spectroscopy.[1-3] In this study, molecular dynamics was utilized to understand low frequency vibrations in highly ordered poly (p-phenylene terephthalmide) (PPTA).A key structural feature of this polymer is the presence of hydrogen bonds.
ELECTROH-DONATING BEHAVIOR OF Co AND Fe IH PROMOTED Rh CATALYSTS
Lin HUANG , An Ming LIU , Wen Gui GUO , Yi De XU
1993, 4(7): 639-640
[Abstract](177) [FullText HTML] [PDF 109KB](0)
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A vacuum heating operation at 623 K on the surfaces of SiO2-supported promoted ca-talysts makes it possible to reveal the electron transfer from Co and Fe additives to Rhatoms:a Rh catalyst containing 1% Eh under CO exhibits geminal CO IR bands only, while the presence of Co and Fe in promoted Rh catalysts results in linear and bridged CO chemisorptions on Rh in connection with their promotion in the selective hydroformylation of propylene.
SYTHESE AND REACTIONS OF HETEROBINUCLEAR COMPLEXES[PhCl2SnM(Cl)(CO)3(CH3CN)2] (M=Mo, W)
Ji Tao WANG , Yun WenZHANG , Yu Ming XU , Chun Ming CUI
1993, 4(7): 641-644
[Abstract](172) [FullText HTML] [PDF 162KB](0)
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The complexes[M(CO)3(CH3CN)3] (M=Mo, W) react with an equimolar quantity of PhSnCl3 in dichloromethane at room tempreture to afford new heterobinuclear complexes[PhCl2SnM(Cl)(CO)3(CH3CN)2] [M=Mo (1); W (2)].The complexes react with two equivalents of PR2R'(R=Ph, R'=Ph, Me; R=Cy, R'=H) to yield stablecomplexes[PhCl2SnM(Cl)(CO)3(PR2R')2].Reaction of[PhCl2SnM (Cl) (CO)3(CH3CN)2]with one equivalent of PPh2(CH2)nPPh2(n=I,2) or bulky phosphine ligands PBu2tCl in dichloromethane at room tempreture to give[PhCl2SnMo(Cl)(CO)3{PPh2(CH2)n-PPh2}].CH2Cl2,[PhCl2SnMo(Cl)(CO)3PBu2tCl].CH2Cl2, respectively.The complexes 1 and 2 react with phosphite donor ligands P(OMe)3 to give[PhCl2SnM(Cl)(CO)2-{P(OMe)3}3].All complexes have been characterized by elemental analysis, IR and 1HNMR spectroscopies.Here we report the preliminary results of this work.
SYNTHFSIS AND CHARACTERIZATION OF LANTHANIDE COMPARTMENTATL COMPLEXES, Ln2[H2 (BAA)2 en]3·pH2O
Jin Xia LIU , Ru Dong YANG
1993, 4(7): 645-648
[Abstract](191) [FullText HTML] [PDF 90KB](1)
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A series of new complexes of formula Ln2[H2(BAA)2en]3nH2 Otwhere Ln-La,Pr, Eu, Cd, Dy, Er, Yb, n-1-4) have been prepared by the reaccLon of lanthanide ions with acycllc compartmental ligand N, N'-bis(benzoylacetylacetone)ethylenediamine(H4(BAA)2 en) in methanol.IR and UV spectra, as well as TC DAT analysis prove that the ligand and the Lanthanide ions have coordinated.The coordination number is 12 and the complexes may be of double sandwiched structure.
HETERONUCLEAR COMPLEX CONTAINING COPPER-LANTHANIDE ARRAYS:THE SYNTHESIS AND CRYSTAL STRUCTURE OF Ln2Cu4L8 (HL)4(OH)2(CIO4)4(H2O)10·2CH3COCH3 (Ln=Tb (1), Y (2); HL=2-Pyridone C5H5NO)
Hong Ye SUN , Ming Jie ZHANG , Chun Hui HUANG , Guang Xian XU , Zhong Sheng JIN , Shong Chun JIN
1993, 4(7): 649-652
[Abstract](145) [FullText HTML] [PDF 155KB](0)
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Reaction of 2-pyridone, copper acetate and terbium (or yttrium) perchlorate in acetone with the mole ratio 6:2:1 results in the formation of heteronuclear complex Ln2Cu<、sub>4L8 (HL)4 (OH)2 (ClO4)4 (H20)10 2CH3COCH3(Ln=Tb (1), Y (2)).By recrystallizing (1) in CHCl3 single crystals were obtained and the structure was determined by four-circle diffractometer.Data showed that the crystal is in space group C2/m with a=27.454(9)Å, b=13, 608Å, c=30.556(11)Å, β=99.89(3)°, v=11245.7(7.5)Å3.The structure was solved by a combination of Patterson method and Fourier technique.The final R value is 0.103.In the structure, four copper and two terbium ions are bridged by 2-pyridone anions to form an essentially octahedral Cu4Tb2 core.The terbium atoms are each eight-coordinate and the copper atoms are five-coordinate.
STRUCTURAL EVIDENCES OF Ru (H)2(H2) (PPh3)3 AT LOW TEMPERATURE
Quan Ling SUO , Xing Ming LIU , Yuan Qi YIN , Dao Sen JIN , Shu Ben LI
1993, 4(7): 653-656
[Abstract](170) [FullText HTML] [PDF 101KB](0)
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FTIR spectrum at liquid nitrogen temperature and 1H NMR of air-sensitive polyhydride Ru(H)2(H2)(PPh3)3 have been measured for the first time.It is found that a fluxional process happens at room temperature, but the structure of Ru(H)2(H2)(PPh3)3 with non-equivalent hydrogens is discernible at low temperature.
FORMATION AND PROPERTIES OF POROUS SILICON LAYER ON HEAVILY DOPED n-Si
Rui Bao JIA , Shi Xun WANG , Guo Xheng LI
1993, 4(7): 657-658
[Abstract](167) [FullText HTML] [PDF 153KB](0)
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The anodic voltammetric curves of heavily doped n-Si in HF solution, on which three different regions have emerged, and were plotted, A porous silicon layer with fine morphology was formed in linear region.
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