2000 Volume 11 Issue 5

1-Ethyl-2-Fluoro Pyridinium Salt:A Highly Efficient Coupling Reagents for Sterically Hindered Peptide Synthesis
Peng LI , Jie Cheng XU
2000, 11(5): 377-380
[Abstract](171) [FullText HTML] [PDF 153KB](0)
Abstract:
1-Ethyl-2-fluoropyridinium tetrafluoroborate(FEP)was shown to be a very efficient coupling reagent for the synthesis of the hindered peptide with fast reaction speed,low racemization and good yields.
The Preparation and Application of two New Types of Oxazaborolidines
Guo Bin RONG , Xing Ming LI , Yong ZHANG
2000, 11(5): 381-382
[Abstract](161) [FullText HTML] [PDF 71KB](0)
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Two new type of 1,3,2-oxazaborolidines were prepared from (1s,2s)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol and were used as catalyst in the asymmetric reduction of acetophenone. The influence of the reaction temperature as well as the effect of the structure of catalyst on the enantioselectivity was investigated. The origin of the products' configuration was discussed.
Asymmetric Transfer Hydrogenation of Ketone Catalyzed by Novel Ru(Ⅱ)-Chiral Sulfonamide Complex
Chun E DONG , Jun Long ZHANG , Wei Zhong ZHENG , Zuo Long YU , Liang Fu ZHANG
2000, 11(5): 383-384
[Abstract](171) [FullText HTML] [PDF 72KB](0)
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Two new chiral Ru(Ⅱ)-sulfonamide complex have been used to catalyze the enantioselective transfer hydrogenation of prochiral ketones and the secondary alcohols are obtained with good to excellent optical yields.
A Facile and Highly Stereoselective Reductive Debromination of Anhydro-6-(R)-Hydroxyethyl-6-Bromopenicillin
Bing ZHENG , Jin Long WU , Shao Jun XU , Jian Feng SHI , Yao Zu CHEN
2000, 11(5): 385-386
[Abstract](155) [FullText HTML] [PDF 78KB](0)
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Reductive debromination of anhydro-6-(R)-hydroxyethyl-6-bromopenicillin 7 by zinc in ammonium acetate gave 9 in 81% yield with high stereoselectivity of 6-(α):6-(β)=13:1.
Simultaneous Reduction of Nitro Group and S-S Bond in Nitrodisulfides by Samarium Diiodide:A New Approach to Benzothiazolines
Xiao Yuan CHEN , Wei Hui ZHONG , Yong Min ZHANG
2000, 11(5): 387-388
[Abstract](156) [FullText HTML] [PDF 92KB](2)
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Nitrodisulfides were reduced by SmI2/HMPA in anhydrous THF at room temperature to produce active intermediates (samarium thiolates and amides), which were "living" double-anions and reacted smoothly with aldehydes or ketones to afford benzothiazolines in good yields under mild and neutral conditions.
A Novel Synthesis of 3,4-Dihydro-(2H)-1,2,4-Benzothiadiaizine-1,1-Dioxides Promoted by Samarium Diiodide
Wei Hui ZHONG , Yong Min ZHANG
2000, 11(5): 389-390
[Abstract](156) [FullText HTML] [PDF 86KB](0)
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3,4-Dihydro-(2H)-1,2,4-benzothiadizine-1,1-dioixdes were prepared in good yields via reductive cyclization of o-nitrobenzenesulfonamides with aldehydes promoted by SmI2 under mild and neutral condition.
The Synthesis of Some Novel N-[α-(Isoflavone-7-O-)Acetyl] Amino Acid Derivatives
Peng LIU , Jun Biao CHANG , Rong Feng CHEN , Qiang WANG , Jing Xi XIE
2000, 11(5): 391-394
[Abstract](153) [FullText HTML] [PDF 174KB](0)
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A series of novel N-[α-(isoflavone-7-O-) acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.
Synthesis and Characterization of a New Organic Up-conversion Laser Dye HMASPS
Yan REN , Qi FANG , Yun Xing YAN , Xiao Met WANG , Zhi LIU , Guangyong ZHOU , Chun WANG , Xian ZHAO , Min Hua JIANG
2000, 11(5): 395-398
[Abstract](174) [FullText HTML] [PDF 142KB](0)
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A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyri-dinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HMASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 8.4% which is higher than that of trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI)1 at the same pump level.
Studies on Agarofurans IV. The Synthesis of 4-Substitutioned Agarofurans
Wu Yan ZHANG , Ji Yu GUO , Xiao Tian LIANG
2000, 11(5): 399-400
[Abstract](159) [FullText HTML] [PDF 87KB](1)
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A new synthetic route for α-agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was performed quantitatively. An ideal condition for cyclization of diol 7 to agarofuran (1) was found.
Synthesis of N-t-Butyl-N'-Aminocarbonyl-N-(Substituted) Benzoylhydrazine Containing α-Aminoalkylphosphonate Groups
Qing Min WANG , Run Qiu HUANG , Zai Guo LI , Rut Lian SHAO
2000, 11(5): 401-402
[Abstract](153) [FullText HTML] [PDF 86KB](1)
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A variety of novel N-t-butyl-N'-aminocarbonyl-N-(substituted)benzoylhydrazines containing α-aminoalkylphosphonate groups were synthesized by the addition of N-t-butyl-N-(substituted)benzoylhydrazines to α-isocyanatoalkylphosphonates, which were synthesized by the reaction of α-aminoalkylphosphonates with triphosgene in good yields. The structures of products including by-products were confirmed by 1H NMR, 31P NMR, IR, mass spectroscopy, and elemental analysis.
Synthesis of Macrocyclic Lactones Building on Double Calix[4]arenes
Qi Yu ZHENG , Chuan Feng CHEN , Zhi Tang HUANG
2000, 11(5): 402-404
[Abstract](154) [FullText HTML] [PDF 89KB](0)
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The macrocyclic lactones building on calix[4]arenes 3a-b and double calix[4]arenes 4a-b were synthesized by the reaction of p-tert-butylcalix[4]arene (1a) or calix[4]arene (1b) with glycol bis(2-chloroacetate) (2). The conditions to improve the yields of double calix[4]arenes have been discussed.
Stereocomplex Formation of Atactic Poly (methyl methacrylate)
Qun GU , De Yan SHEN
2000, 11(5): 405-406
[Abstract](155) [FullText HTML] [PDF 85KB](0)
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Stereocomplexes formed in atactic poly(methyl methacrylate) (a-PMMA) films cast form different solvents were studied by means of Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The growth of stereocomplex was a function of annealing temperature and annealing time, respectively.
Interaction between N-Phospho-Amino Acids and Nucleoside in Aqueous Medium
Yu Fen ZHAO , Jian Jun HU , Yong JU
2000, 11(5): 407-408
[Abstract](161) [FullText HTML] [PDF 86KB](0)
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Nucleosides were phosphorylated with different N-(O, O-diisopropyl) phosphoryl amino acids to give nucleoside mono phosphates in aqueous solution. 2', 3', and 5'-isomers had been confirmed by comparison with authentic samples on the basis of HPLC analysis. The conversion percentage of nucleoside indicated that N-(O, O-diisopropyl) phosphoryl aspartic acid reacted with adenosine and guanosine at a much higher rate than other kinds of N-phosphoryl amino acids, while phosphorylation of cytidine and uridine was relatively easy by using N-(O, O-diisopropyl) phosphoryl threonine. The result could give some clue to the prebiotic code origin of nucleic acid and protein.
A New Azafluorenone Alkaloid from Alphonsea monogyma
Nian Yun YANG , Ning XIE , Ling Yi KONG , Gang LI
2000, 11(5): 409-410
[Abstract](172) [FullText HTML] [PDF 66KB](0)
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A new azafluorenone (onychine) alkaloid, 6,7-dimethoxy-5-hydroxy onychine N-oxide, was isolated from the stem and branch of Alphonsea monogyma. Its structure was established on the basis of spectral and chemical analysis.
Diterpenoid Alkaloids from Aconitum racemulosum Franch var. pengzhouense
Chong Sheng PENG , Xi Xian JIAN , Feng Peng WANG , Dong Lin CHEN
2000, 11(5): 411-414
[Abstract](155) [FullText HTML] [PDF 93KB](0)
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A new diterpenoid alkaloid, racemulodine (1), was isolated from the whole plants of Aconitum racemulosum Franch var. pengzhounense.
Two New Iridoid Glucosides from Clerodendrum serratum
Xiao Mei WEI , Qi Xiou ZHU , Jin Chun CHEN , Dong Liang CHENG
2000, 11(5): 415-416
[Abstract](164) [FullText HTML] [PDF 80KB](0)
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Two new iridoid glucosides, named 7β-coumaroyloxyugandoside (1) and 7β-cinnamoyloxyugandoside (2) were isolated from the leaves of Clerodendrum serratum, and their structures were elucidated by spectral means.
Demethoxylation and O-Demethylation of Pseudaconine and Isotalatizidine
Ju Zheng FAN , Zheng Bang LI , Qiao Hong CHEN , Feng Peng WANG , Bo Gang LI
2000, 11(5): 417-420
[Abstract](258) [FullText HTML] [PDF 127KB](10)
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Demethoxylation and O-demethylation of the norditerpenoid alkaloids pseudaconine and isolatatizidine were described.
Oxidation of the Norditerpenoid Alkaloids Isotalatizidine and 6-Epiforsticine
Zheng Bang LI , Qiao Hong CHEN , Feng Peng WANG , Bo Gang LI
2000, 11(5): 421-424
[Abstract](156) [FullText HTML] [PDF 136KB](0)
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Oxidation of 1 with KMnO4 in acetone-H2O (1:1) for 1h gave nevadenine 2 (38%). But, 3 was formed in 98% yield when prolonging time and raising temperature (40℃). Reaction of 1 and 10 with Conforth reagent afforded the ketones 11 (55%), 12 (30%), and 13 (13%), 14 (20%), respectively. While oxidation of 7 and 15 with a variety of the oxidizing agents gave 17 only in low 20% of yield besides the minor 16. In addition, 1 was converted to 2 by the fungi Curvularia lunata.
Determination of Phosphorus by Inductively Coupled Plasma Atomic Emission Spectroscopy after Hydride Generation
Zhe Feng FAN , Li Min DU
2000, 11(5): 425-426
[Abstract](173) [FullText HTML] [PDF 87KB](0)
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A continuous phosphine (PH3) generation was developed and applied to the sensitive detection of phosphorus by ICP-AES. Phosphate ion in aqueous solution was converted to phosphine by passing the sample solution through an incandescent copper silica-tube. Detection limit is 2 ng/mL. The relative standard deviation is 4.2% for 20 ng/mL. The method is rapid and simple with low contamination and high sensitivity.
Chemiluminescence Determination of Molybdenum by on-Line Reduction with a Flow Injection System
Zhi Jia ZHU
2000, 11(5): 427-430
[Abstract](161) [FullText HTML] [PDF 139KB](0)
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The chemiluminescence (CL) reaction between lucigenin (Lu) and molybdenum (Ⅲ) produced by a Jones reductor was investigated using a flow injection system. On the basis of this, a novel method for the determination of trace amount of molybdenum has been established. The emission intensity was linear with molybdenum concentration in the range of 0.1-1000 ng/mL; the detection limit was 0.02 ng/mL molybdenum; the relative standard deviation was less than 2% for the determination of 0.1 ng/mL molybdenum (n=11). The method has been applied successfully to the analysis of trace molybdenum in water and steel samples.
Spectrofluorimetric Determination of Trace Terbium(Ⅲ) Using 2,6-Bis-(1'-phenyl-3'-methyl-5'-oxopyrazole-4') Pyridinediacyl and N-Cetylpyridium Bromide
Jin Zhang GAO , Qi Liang DENG , Wu YANG , Jing Guo HOU , Bac Wei ZHAO , Jing Wan KANG
2000, 11(5): 431-434
[Abstract](159) [FullText HTML] [PDF 134KB](0)
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A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2,6-bis-(1'-phenyl-3'-methyl-5'-oxopyrazole-4') pyridinediacyl (H2PMBPP) and N-cetylpyridium bromide (CPB), at an apparent pH=5.0 provided by a hexamethylenetetramine (5% w/w)-hydrochloric acid buffer, is proposed. The calibration graph is linear in the range from 1.43×10-5 to 0.1589 μg/ml.
HPLC Determination of Neurotoxin β-N-oxalyl-L-α,β-diaminopropionic acid and Its α-Isomer in Lathyrus sativus by Precolumn Derivatization with 1-Fluoro-2,4-dinitrobenzene
Fei WANG , Xiong CHEN , Qian CHEN , Xin Chen QIN , Zhi Xiao LI
2000, 11(5): 435-438
[Abstract](160) [FullText HTML] [PDF 174KB](0)
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A rapid and simple method is presented for determining β-N-oxalyl-α,β-diaminopropionic acid (β-ODAP) and its much less toxic α-isomer (α-ODAP) in Lathyrus sativus. Seed and foliage extracts of Lathyrus sativus were treated with 1-fluoro-2,4-dinitrobenzene (FDNB) and a reversed-phase high-performance liquid chromatographic method for the separation of the derivatives in the pmol range is reported.
A New Conductivity Detector for Capillary Electrophoresis
Zuan Guang CHEN , Jin Yuan MO , Tian Yao XIE , Li Shi WANG , Xiao Yun YANG , Kong ZHANG , Min Sheng ZHANG
2000, 11(5): 439-442
[Abstract](154) [FullText HTML] [PDF 109KB](0)
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A new conductivity detector for capillary electrophoresis consisting of an electrochemical cell and a conductive meter was developed. In the cell, the microelectrode and capillary were inserted through the cell wall and fixed by screws and sealing ring, the ends of microelectrode and capillary were located by a guide with two cross holes. LOD for K+ was 1.5×10-5 mol/L.
Oscillographic Chronopotentiometry with High and Low Frequency Current
Jian Bin ZHENG , Xiu Qi ZHANG , Hong GAO
2000, 11(5): 443-446
[Abstract](164) [FullText HTML] [PDF 135KB](0)
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A novel electroanalytical method, oscillographic chronopotentiometry with high and low frequency current, is presented in this paper. With this method, the sensitivity of almost all kinds of oscillographic chronopotentiometry can be enhanced about one order.
Theory Study on Structures and Vibrational Frequencies of Pyruvic acid
Dong Met DU , Ai Ping FU , Zheng Yu ZHOU
2000, 11(5): 447-450
[Abstract](162) [FullText HTML] [PDF 179KB](3)
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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 pyruvic acid. The scaled B3LYP/6-31G* frequencies correspond well with available experimental assignment of the functional vibrational modes and the mean absolut devation is only 12.3cm-1.
Reactivity Ratios for Microemulsion Copolymerization of N-butyl Maleimide and Styrene
You Liang ZHAO , Hua Ming LI , Peng Sheng LIU
2000, 11(5): 451-452
[Abstract](153) [FullText HTML] [PDF 92KB](0)
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The oil-in-water microemulsion containing N-butyl maleimide(NBMI, M1) and styrene(St, M2) was prepared. The complexation properties of NBMI and St in microemulsion were investigated by means of 1H-NMR. With the participation of charge-transfer complex(CTC), four reactivity ratios and the relative reactivity of free monomers and CTC were obtained. The result was compared with that measured by Mayo-Lewis method.
The Effect of pH Difference Between Two Phases on the Partition of Lysozyme in Aqueous Two-Phase System
Yan XU , Jun LU , De Qian LI
2000, 11(5): 453-454
[Abstract](132) [FullText HTML] [PDF 79KB](0)
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In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases, and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.
Electrochemical Properties of Spinel LiMn2O4-δ Fδ for Cathode Materials of Secondary Lithium-ion Battery
Zhao Yong CHEN , Xing Quan LIU , Zuo Long YU
2000, 11(5): 455-458
[Abstract](132) [FullText HTML] [PDF 127KB](0)
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The spinel LiMn2O4-δ Fδ cathode materials were synthesized by solid-state reaction, with calculated amounts of LiOH·H2O, MnO2(EMD), LiF. The results of electrochemical test demonstrated that these new materials exhibited excellent electrochemical properties. Its initial capacity reached~115 mAh·g-1 and reversible efficiency is about 100%. After 60 cycles, its capacity was still around 110 mAh·g-1, with nearly 100% reversible efficiency.
X-ray Crystal Structure and Molecular Mechanics Calculations of (2,6-iso-dipropyl-phenylamide) Dimethyl (tetra-methylcyclopenta-dienyl) Silane Titanium Dichloride
Tai Qi LIU , Da Wei GUO , Yong Hua LIN , Xiao Zhen YANG , You Liang HU
2000, 11(5): 459-462
[Abstract](133) [FullText HTML] [PDF 177KB](0)
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Crystal and molecular structure of (2,6-dipropylphenylamide) dimethyl (tetra-methyl cyclopentadienyl) silane titanium dichloride (Ⅰ) was fully characterized by X-ray diffraction. The crystal is obtained from a mixture of ether/hexane as orthorhombic, with a=12.658 (3)Å, b=16.62 (3)Å, c=11.760 (2)Å, V=2474.2 (9) Å 3, Z=4, space group Pnma, R=0.0399. Componud Ⅰ compose of the π-bounded ring with its dimethylsilyl-dipropyl phenyl amido group and the two terminal chloride atoms coordinated to central metal to form a so-called constrained geometry catalyst (CGC) structure. The result of molecular mechanics (MM) calculations on compound I shows that bond lengths and bond angles from the MM calculation are comparable to the data obtained from the X-ray diffraction study. The relation of the structure of CGCs and their catalytic activity by MM calculations is also discussed.
Cation-π Interactions. Synthesis and Crystal Structure of Palladium Complex:[K(DB18C6)]2[Pd(SCN)4]
Jian Min DOU , Ying LIU , Lan Ying ZHU , De Zhi SUN , Pei Ju ZHENGZ , Chen Xia DU , Yu ZHU
2000, 11(5): 463-466
[Abstract](139) [FullText HTML] [PDF 136KB](0)
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A novel Pd(Ⅱ)-dibenzo-18-crown-6 (DB18C6) complex[K(DB18C6)]2[Pd(SCN)4] has been isolated and characterized by X-ray diffraction analysis. In the solid state, it displays a quasi-one-dimensional infinite chain of two[K(DB18C6)]+ complex cations and a[Pd(SCN)4]2- anion bridged by K+-π interactions between adjacent[K(DB18C6)]+ units.
Nanostructured Lead Sulfide Containing Nanoholes Templated by Lyotropic Hexagonal Liquid Crystals
Yan LI , Qing Min ZHANG , Fu Zhi HUANG , Zhen Nan GU
2000, 11(5): 467-470
[Abstract](151) [FullText HTML] [PDF 177KB](0)
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The hexagonal liquid crystal mediated synthesis of nanostructured PbS was studied. Thioacetamide and lead acetate were used as the sulfide and lead source, respectively. It was found that the nanohole structure of PdS was formed in this system.
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