1998 Volume 9 Issue 8

Elimination Reaction of α, ω-Diols by Magnesium
Ji Mao LIN , Hui ZHANG , Ai You HAO , Qin Zheng YANG
1998, 9(8): 697-698
[Abstract](166) [FullText HTML] [PDF 54KB](0)
1,3-Propanediol, 1,4-butanediol or 1,5-pentanediol reacts with magnesium to form corresponding magnesium alkoxides, which eliminate water with the formation of cyclic ethers and, respectively, allyl alcohol, 3-buten-l-ol and 4-penten-l-ol.
Conjugate Addition Reactions of Functionalized Organozinc-copper Reagents to α, β-Unsaturated Esters
Yu Lai HU , Jian Hua YU , Shi Yan YANG , Yuan Qi YIN , Tian Quan JIAO , Jin Xian WANG
1998, 9(8): 699-700
[Abstract](159) [FullText HTML] [PDF 80KB](0)
Functionalized organozic reagents can easily conduct 1,4-addition reaction with unsaturated esters in the persence of Cu(OAc)2 and LiCI under very mild conditions to give the products in excellent yields.
Application of Fast Radical Rearrangement in the Mechanistic Investigation of Intramolecular C-H Insertion by Rh(Ⅱ)-Mediated Carbenoids
Jian Bo WANG , Feng Ting LIANG
1998, 9(8): 701-704
[Abstract](164) [FullText HTML] [PDF 149KB](0)
In order to investigate the reaction mechanism of intramolecular C-H insertion by Rh(Ⅱ)-mediated carbenoids with rrans-(2-phenylcyclopropyl)carbinal radical as the mechanistic probe, diazo compounds 2-(2-phenylcyclopropyl)ethyl diazoacetoacetate 8a and methyl 2-diazo-3-oxo-6-(2-phenylcyclopropyl)hexanoate 8b have been synthesized. Preliminary investigation of the intramolecular C-H insertion with Rh2(OAc)4 as catalyst supports a concerted insertion process.
A Novel Example of Hetero Diels-Alder Reaction
Yan ZHANG , Yun Zhen JIANG , Xiao Tian LIANG
1998, 9(8): 705-706
[Abstract](151) [FullText HTML] [PDF 82KB](0)
2, 3, 3a, 4, 5, 9b-hexahydro-8-(N-methylsulfamylmethyl)-4-phenylfuro[3, 2-c]quinoline was obtained when the alkylation of compound 1 was carried out with THF as solvent. The structure of the product was determined and the mechanism of the reaction was studied and proved by the imitation reaction.
Photosynthesis of Tetrahydroprotoberberines with Electron withdrawing Groups on Ring D
Yong Zhou HU , Qi Ting ZHOU , Dong Lu BAI
1998, 9(8): 707-710
[Abstract](165) [FullText HTML] [PDF 139KB](0)
A number of tetrahydroprotoberberines with electron-withdrawing groups on ring D have been synthesized via photocyclization of 2-formyl-1 -benzylideneisoquinoline enamides as the key step.
Synthesis of Alkyl 4(4'-octyloxy-4"-biphenylcarboxy)-benzenesulfonates
Zhi Ping LI , Guo Du REN
1998, 9(8): 711-713
[Abstract](154) [FullText HTML] [PDF 100KB](0)
Five new Liquid Crystals with sulfonate units were synthesized. And they were determined by FT-IR and MS. The points of phase transition and the temperature ranges of liquid crystals were measured by means of DSC and PLM (Polarized Light Microscopy).
A Convenient Method for the Stereoselective Synthesis of 7α-Hydroxycholesterol
Ling Jie GAO , Tian Zeng ZHAO , Guang Dian HAN
1998, 9(8): 715-716
[Abstract](149) [FullText HTML] [PDF 87KB](0)
7α-Hydroxycholesterol was prepared from cholesteryl acetate via allylic bromination followed by hydroxylation in 73% overall yield.
First Total Synthesis of (-)-4-0-(6'-hydroxy-7'(9')-dehydro-6',7'-dihydrogeranyl)-coniferyl Alcohol
Zuo Sheng LIU , Chu Sheng HUANG , Jiong LAN , Yu Lin LI
1998, 9(8): 717-720
[Abstract](151) [FullText HTML] [PDF 114KB](0)
The reduction of 2,3-epoxy alcohol, prepared from the Sharpless asymmetric epoxidation, with the system of Ph3P, iodine, imidazole, 2,6-lutidine and water in Et20/CH3CN, gives a chiral secondary allylic alcohol in 94% yield and 92% e.e.. Using this reaction as the key step, we synthesized (-)-coniferyl alcohol derivative 1 starting from the geraniol through nine steps in an overall yield of 39%.
Synthesis and Herbicidal Activity of 2-Benzoyliminopyrimido[3,2-b]-1 2,4-Thiadiazolines
Si Jia XUE , Dong Yun TAN , Chang You SUN
1998, 9(8): 721-722
[Abstract](153) [FullText HTML] [PDF 68KB](0)
A series of 2-benzoyliminopyrimido[3,2-b]-1,2,4-thiadiazolines were synthesized and tested for herbicidal effects. All of them are new compounds and their structures were confirmed by 1HNMR, IR, MS. The preliminary herbicidal tests show that some of the target compounds have potent activity and very good selectivity to rice.
Bioisosterism between Sulfonyl Group and Phosphoryl Group-The Synthesis of New ALS Inhibitors N-(Arylamino Hydroxyl Phosphoryl)-N'-(4,6-Dimethoxypyrimidine-2-yl)ureas
Guo Feng ZHAO , Hua Zheng YANG , Lin Xiu WANG , Yong Hong LI
1998, 9(8): 723-725
[Abstract](180) [FullText HTML] [PDF 88KB](0)
In view of the isosterism of sulfonyl group (-SO2-) and phosphoryl group [-P(0)(0R)-, R=H, CH3, C2H5, etc], a new type of ureas, that is, N-phosphoryl-N'-(4,6-dimethoxypyrimidin-2-yl) ureas 2 were synthesized and shown to be a new class of acetolactate synthase (ALS) inhibitors.
The Synthesis of Cyclotriphosphazene Liquid Crystals
Yong Gang YANG , Jian Xun WEN
1998, 9(8): 727-729
[Abstract](159) [FullText HTML] [PDF 85KB](0)
Four functional cyclotriphosphazene liquid crystals have been synthesized. Their phase transition temperatures have also been measured by polarizing textural observation and confirming by DSC.
Catalytic Hydrolysis of Lipophilic Amino Acid Esters by Metallomicelles as Carboxypeptidase A Models
Xiao Qi YU , Jing Song YOU , Qing Xiang XIANG , Qian Shun YAN , Ru Gang XIE
1998, 9(8): 731-732
[Abstract](154) [FullText HTML] [PDF 86KB](0)
Lipophilic complexes of macrocyclic 12-membered dioxotetraamine ligand bearing bis-hydroxy groups as functional pendants are effective catalysts for the hydrolysis of amino acid es- ters in micellar media, and the rate enhancement of more than 10-fold were observed.
A New 1β-hydroxy-ent-kaurenoid From Isodon Enanderianus
Yan Hong WANG , Yao Zu CHEN , Zhong Wen LIN , Han Dong SUN
1998, 9(8): 733-734
[Abstract](166) [FullText HTML] [PDF 81KB](0)
A new 1 p-hydroxy-ent-kauren diterpenoid, enanderianin C 1, has been isolated from the leaves of Isodoti enanderianus, and its structure has been elucidated by spectroscopic evidences.
Oligostilbentes from Vitis DavidⅡ
Wen Wu LI , Bo Gang LI , Yao Zu CHEN
1998, 9(8): 735-736
[Abstract](156) [FullText HTML] [PDF 84KB](0)
A novel tetrastilbene, davidol A, was isolated from the stems of Vitis davidii together with the previously known resveratrol, (+)-ε-viniferin; ampelopsin C; ampelopsin E; vitisin A and hopeaphenol. Its structure was elucidated mainly by ID and 2D NMR analyses.
A New Triterpenoid from Teucrium Integrifolium
Xing Liang CHEN , Tian En WANG , Bei JIANG , Zhong Wen LIN , Han Dong SUN
1998, 9(8): 737-738
[Abstract](159) [FullText HTML] [PDF 94KB](0)
A new ursane-type triterpene, 3β-hydroxy-urs-5(6)-en-28-oic acid 1, was isolated from the aerial parts of Teucrium integrifolium and characterized. The structure of this new compound was mainly established by 2D NMR techniques (COSY, HETCOR, HMBC).
A New Pregnane Glycoside from Dioscorea collettii var. hypoglauca
Ke HU , Ai Jun DONG , Hisayoshi KOBAYASHI , Shigeo IWASAKI , Xin Sheng YAO
1998, 9(8): 739-742
[Abstract](162) [FullText HTML] [PDF 146KB](0)
A new pregnane glycoside hypoglaucin G was isolated from Dioscorea collettii var. hypoglauca by bioactivity-guided fractionation, which showed a moderate activity of inducing morphological deformation of the Pyricularia oryzae mycelia. The structure of hypoglaucin G was established as 16β-(4'-methyl-5'-0-β-D-glucopyranosyl-pentanoyloxy)-pregn-5-en-3β-ol-20-one-3-0-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)-]-β-D-glucopyranoside by che- mical evidence and spectral analysis, especially by 2D-NMR techniques.
Chemiluminescence flow Sensor for determination of the Ammonium ion
Bao Xin LI , Wei QIN , Zhu Jun ZHANG
1998, 9(8): 743-745
[Abstract](149) [FullText HTML] [PDF 115KB](0)
A novel chemiluminescence (CL) sensor for NH4+ combined with flow injection analysis is presented in this paper. It is based on the inhibition effect of NH4+ on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hypochlorous acid electrogenerated on-line. The sensor responds linearly to NH4+ concentration in 1.0×lO-6-4.0×10-9 g/ml range. A complete analysis could be performed in 1 min. The system is stable for 200 determination
The Electrochemical Behavior and the Determinationof Bavistin on Glassy Carbon Electrode
Yuan Zhe PIAO , Gui Fen WANG
1998, 9(8): 747-748
[Abstract](169) [FullText HTML] [PDF 78KB](0)
In this paper, the electrochemical behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4CI, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse stripping voltammetry was applied for determining MBC in grains. The detection limit is 4×lO-8mol/L.The recovery is from 91.3% to 95.7%. The method has advantages of simplicity and high sensitivity.
Study on Conductivity Detection for Capillary Electrophoresis--Design of a new type of miniature conductance cell
Wen Feng LIU , Jin Yuan MO , Bing Yi YANG
1998, 9(8): 749-751
[Abstract](154) [FullText HTML] [PDF 129KB](0)
A new kind of miniature conductance cell with thick electrodes was made, which has high resolution, high sensitivity, but no dead volume. A set of capillary electrophoresis device with on-column conductivity detector was assembled. In order to test the performance of this kind of mini-cell, different kinds of mini-cells were used to detect Li+, Na+, K+, Ca2+and Mg2+ ions.
A Study of Multi-order Semidifferential Oscillographic Chronopotentiometry
Jian Bin ZHENG , Min GAO , Ye Wei FU , Hong GAO
1998, 9(8): 753-756
[Abstract](160) [FullText HTML] [PDF 127KB](0)
By applying the convolution technique to the treatment of oscillographic signal, a new electroanalytical method, 0.5-3.5 order differential A.C. oscillographic chronopotentiometry is presented. This note represents the experimental circuits, principle and characteristics of the method.
A New Amperometric Detector Cell for Capillary Zone Electrophoresis
Xiao Yun YANG , JinYuan MO , TianYao XIE , Bing Yi YANG , Wen Feng LIU , Pei Xiang CAI
1998, 9(8): 757-760
[Abstract](155) [FullText HTML] [PDF 154KB](0)
A simple and convenient electrochemical detection cell for capillary electrophoresis is described in this paper. In this cell, alignment of the capillary working electrode with the separation capillary outlet can be achieved precisely and easily without the aid of the micropositioner or microscope. With end-column detection, the applicability of the cell as an amperometric detector for capillary electrophoresis is demonstrated by running several phenolic compounds in 50μim i.d. capillary with a capillary Pt electrode as the working electrode. Results obtained are satisfactory.
Intensity Exaggeration of Endohedral Metallofullerenes in Laser Desorption-Ionization Time-of-Flight Mass Spectrometry
Da Yong SUN , Wen Guo XU , and Shu Ying LIU
1998, 9(8): 761-764
[Abstract](157) [FullText HTML] [PDF 168KB](0)
The laser-desorption-ionization time-of-flight mass spectrometry and desorption-electron-ionization mass spectrometry were employed for the characterization of metallofullerenes extract. It was found that the relative intensities of metallofullerenes in this positive-ion, negative-ion LD-TOF MS and DEI MS were much different. This phenomenon should have relationship with the peculiar ionization energies and electron affinities of metallofullerenes.
99Ru and 13C-NMR Spectra for the Tris Chelates of 5-Substituted 1,10- Phenanthrolines with Ruthenium(Ⅱ)
1998, 9(8): 765-766
[Abstract](173) [FullText HTML] [PDF 93KB](0)
13C and 99Ru-NMR chemical shifts are reported for the ruthenium(Ⅱ) tris complexes of 5-substituted 1,10-phenanthrolines. It has been found that both of them are affected by the substituents on the phenanthrolines in a direction consistent with that expected from the electron withdrawing ability of the substituent.
Study on the C60-Caged States of H2 and N2
Li Jin XU , Chuan Bao ZHU , Ji Min YAN
1998, 9(8): 767-770
[Abstract](158) [FullText HTML] [PDF 168KB](0)
The states of small molecule H2 and N2 in the C60 cage have been studied. It is shown that the molecular stable configurations of the caged states exhibits little change compared with the free states, but the bond intensities of the caged states have become much stronger.
A Detailed Dynamics Study of the Reaction CH4+Cl→HCl+CH3
Li Jin XU , Xue Bin WANG , Ji Min YAN , Fan Ao KONG
1998, 9(8): 771-774
[Abstract](175) [FullText HTML] [PDF 145KB](0)
The detailed dynamics of the CH4+CI→HC1+CH3 reaction has been investigated by means of the quasiclassical trajectory approach. The properties analyzed can be interpreted in terms of the main topological features of the potential energy surface used. On the basis of the theoretical results, two reaction channels are proposed: one is a direct channel and the other is a complex one.
Microwave Effect On Partial Oxidation of Methane to Syngas over Ni/ZrO2
Xian Jun BI , Xiao Guang XIE , Ai Hong DUAN , Pin Jie HONG , Shu Shan DAI
1998, 9(8): 775-777
[Abstract](144) [FullText HTML] [PDF 115KB](1)
The partial oxidation of methane to syngas over Ni/ZrO2 catalyst irradiated by microwave has been studied. Compared with a conventional heating mode, the temperature of the catalytic bed is much lower and there is a higher selectivity of CO and H2 with microwave irradiation.
Molecular Dynamics Studies of Collapse Stages in the chain folding process of Polyethylene
Qi LIAO , Xi Gao JIN
1998, 9(8): 779-782
[Abstract](127) [FullText HTML] [PDF 122KB](0)
Molecular dynamics simulations of model polyethylene chains with various lengths up to 4000 CH2 units were performed. Our results verified that the modification of force fields to demonstrate the collapse stages in the folding process is not necessary. The transition between the stages of chain folding became sharp, and the clusters became stable as the chain became longer.
Synthesis and Structural Characterization of Adduct [La(NO3)3·4H2O]·2(BQEB)
Wen Xiang ZHU , Bao Di GOU , Yong An ZHANG , Yan LI , Xue An CHEN
1998, 9(8): 783-784
[Abstract](137) [FullText HTML] [PDF 81KB](1)
A new podand compound o-Bis(8'-quinolyloxy) ethylenoxyl benzene (BQEB) was prepared. A lanthanum adduct with BQEB was synthesized and its structure was characterized by X-ray crystal analysis. The La(Ⅲ) is ten-coordinated to the three N03+ and four H20. Two podand molecules are linked to the coordination core by four hydrogen bonds. The crystal is packed in the manner of.LLMLLMLL.
Synthesis and Characterization of Chiral Binuclear Organolanthanide and Yttrium Alkoxides Containing Cyclopentudienyl Ligand
Chang Tao QIAN , Tai Sheng HUANG
1998, 9(8): 785-787
[Abstract](132) [FullText HTML] [PDF 98KB](0)
Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy) with 0.5 equimolar chiral diol in THF (tetrahydrofuran) at -78℃ at room temperature. All the complexes were characterized by elemental analysis, IR and MS spectra.
Mechanism of Dealumination of NaY Zeolite with Oxalic Acid
Hui LIU , Xing Yun LIU , Xuan Wen LI , Xiao Jie XU
1998, 9(8): 789-790
[Abstract](159) [FullText HTML] [PDF 72KB](1)
Dealuminated Y zeolite with high crystallinity is obtained from NaY zeolite by treatment with oxalic acid in a buffering system. The effect of dealumination conditions on the degree of dealumination and the crystallinity of the reformed zeolite is discussed. A mechanism for the reaction is proposed.
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