2006 Volume 17 Issue 6

Synthesis of Novel C2-Symmetrical Bidentate Phosphoramidite Ligands for Rh-catalyzed Asymmetric Hydrogenation of β-(Acylamino)acrylates
Qing Heng ZENG , Xiang Ping HU , Xin Miao LIANG , Zhuo ZHENG
2006, 17(6): 711-713
[Abstract](194) [FullText HTML] [PDF 77KB](1)
Two new C2-symmetrical bidentate phosphoramidite ligands were synthesized and employed in the Rh-catalyzed asymmetric hydrogenation of β-(acylamino)acrylates, up to 89% ee with full conversions was obtained.
An Efficient Synthesis of Ethyl 7-Chloro-6-fluoro-1-methyl-4-oxo-1, 4-dihydro-[1, 3]thiazeto[3, 2-a]quinoline-3-carboxylate as Intermediate of the Prulifloxacin Containing Tricyclic Fluoroquinolone
Shu Tao MA , Hong Xiang LOU
2006, 17(6): 714-716
[Abstract](176) [FullText HTML] [PDF 114KB](0)
Novel ethyl 7-chloro-6-fluoro-1-methyl-4-oxo-1, 4-dihydro-[1, 3]thiazeto[3, 2-a]quinoline-3-carboxylate 2 was prepared from 3-chloro-4-fluoroaniline in eight steps. It can be used as a new intermediate for the synthesis of tricyclic fluoroquinolones.
The Studies of Rhodium-catalyzed Ring Opening Reaction of N-Boc azabenzonorbornadiene with Heteroatom Nucleophiles
Er Chang LIU , Ding Qiao YANG , Ying Feng HAN , Jian Xia DONG
2006, 17(6): 717-719
[Abstract](200) [FullText HTML] [PDF 112KB](0)
A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine's derivatives were nucleophiles in this reaction. The yields of the products 2a-f are good and the regioselectivity are excellent.
Synthesis and Antitumor Activity of 7-Substituted Derivatives of Homocamptothecin
Zhen Yuan MIAO , Wan Nian ZHANG , Jian Zhong YAO , Chun Quan SHENG , Yun Long SONG , Hui XU , Min ZHANG , Jing ZHANG
2006, 17(6): 720-722
[Abstract](165) [FullText HTML] [PDF 157KB](0)
Thirteen homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by the standard MTT method. The results showed that some of the homocamptothecin derivatives had higher antitumor activity than topotecan.
Efficient and Eco-friendly Process for the Synthesis of Bi(indolyl)methanes Catalyzed by Sodium Hydrogensulfate Monohydrate in Ionic Liquid n-Butylpyridinium Tetrafluoroborate
Li Ping ZHANG , Yi Qun LI , Mei Yun ZHOU
2006, 17(6): 723-726
[Abstract](175) [FullText HTML] [PDF 44KB](0)
Efficient electrophilic substitution reaction of indoles with various aromatic aldehydes were carried out with a catalytic amount of sodium hydrogensulfate monohydrate (NaHSO4·H2O) in ionic liquid n-butylpyridinium tetrafluoroborate ([Bpy]BF4) to afford the corresponding bi(indolyl)methanes in excellent yields. The notable advantages of this protocol in terms of low cost of catalyst and ionic liquid, mild conditions, simple operation, short reaction time, high yields and recycling of the ionic liquid.
Asymmetric Syntheses of Osmundalactones and 5-Hydroxy-2-hexen-4-olides from 4-Benzyloxy-5-hydroxy-2(E)-hexenoate
Xi Ying ZHAO , Machiko ONO , Hiroyuki AKITA , Yu Ming CHI
2006, 17(6): 727-729
[Abstract](188) [FullText HTML] [PDF 51KB](2)
(+)-(4S, 5R)- and (-)-(4R, 5S)-osmundalactones as well as (+)-(4R, 5S)- and (-)-(4S, 5R)-5-hydroxy-2-hexen-4-olides were synthesized by a concise and efficient synthesis method starting from 4-benzyloxy-5-hydroxy-2(E)-hexenoate in good yield with over 99% e.e..
Total Synthesis of L-Oleandrose and L-Cymarose from an Achiral Precursor, Methyl Sorbata
Xi Ying ZHAO , Machiko ONO , Hiroyuki AKITA , Yu Ming CHI
2006, 17(6): 730-732
[Abstract](173) [FullText HTML] [PDF 107KB](0)
2, 6-Dideoxy sugars L-oleandrose 1 and L-cymarose 2, the key carbohydrate of antibiotics and cardiac glycosides, were synthesized by an efficient synthetic method from an achiral precursor, methyl sorbate.
Iodine-catalyzed Synthesis of α-Amino Phosphonates
Li Ting DONG , Yun Cheng LI , Ming YAN
2006, 17(6): 733-735
[Abstract](197) [FullText HTML] [PDF 41KB](5)
Iodine was found to be an efficient catalyst for the one pot synthesis of α-amino phosphonate from aldehydes, anilines and diethyl phosphite. The influences of the iodine loading, reaction solvent, the structure of aldehyde and aniline on the reaction were studied.
Improved Electrochemical Synthesis of Nitro-substituted 1-Aryl-2-pyrrolidinecarbonitriles
Wei LIU , Yuan MA , Ying Wu YIN , Yu Fen ZHAO
2006, 17(6): 736-738
[Abstract](175) [FullText HTML] [PDF 85KB](1)
In this paper, we described an improved electrochemical method for synthesis of some1-aryl-2-pyrrolidinecarbonitrile derivatives bearing an electron-withdrawing group (NO2). The electrochemical synthesis of titile compounds has been successfully performed in an undivided cell in reasonable yields.
Oxidative Esterification of Methacrolein to Methyl Methacrylate over Supported Palladium Catalyst
Wei ZHAO , Wei Guo CHENG , Zeng Xi LI , Lei WANG , Xiang Ping ZHANG , Suo Jiang ZHANG
2006, 17(6): 739-742
[Abstract](181) [FullText HTML] [PDF 169KB](0)
Supported palladium catalysts, which were used in the oxidative esterification of methacrolein to methyl methacrylate, have been prepared with different carriers and Pd precursors.Experimental results revealed that Pd catalysts with γ-Al2O3 support and Na2PdCl4 precursor showed good performance. Pd catalyst modified with Pb and Mg indicated that Pd-Mg bimetallic catalyst exhibited considerably higher activity and Pd-Pb exhibited both higher activity and selectivity. 92.27% methacrolein conversion and 90.57% methyl methacrylate selectivity were obtained on Pd-Pb-Mg catalyst.
New CO2-philic Compounds: Design, Synthesis and Solubility in Supercritical Carbon Dioxide
Peng BIE , Hai Jian YANG , Yu BAI
2006, 17(6): 743-746
[Abstract](179) [FullText HTML] [PDF 126KB](0)
A series of gluscose derivatives were designed, synthesized, and their structures were confnmed by IR, NMR and elementary analysis. All new compounds are highly soluble in liquid or supercritical carbon dioxide. The compound with electron-withdrawing substituent on benzene ring had even better solubility than the compounds with electron-donating substituent.
Synthesis and Characterization of Picolinamide Calix[6]arenes Derivatives
Dong Qing LIU , Ya Qing FENG , Hao Hui GU , Wen Liang XU
2006, 17(6): 747-750
[Abstract](173) [FullText HTML] [PDF 122KB](0)
Three full-substituted calix[6]arenes containing the picolinamide groups were synthesized and characterized by IR, 1HNMR and MS, after series reactions, including lower rim etherification, upper rim ipso-nitration, reduction, amidation.
Synthesis of a Novel Chiral Trihydroxamic Acid Containing L-Pro-L-Ala-L-Ala-β-(HO)Ala-OMe Unit
Lang Tao SHEN , Ting YANG , Hong Yu LI , Ji HU , Zhi Fu LUO
2006, 17(6): 751-754
[Abstract](182) [FullText HTML] [PDF 147KB](0)
An N-hydroxyl peptide unit of H-L-Pro-L-Ala-L-Ala-β-(BnO)Ala-OMe was synthesized by stepwise chain building method in solution. Then, based on nitrilotriacetic acid backbone and this N-hydroxyl peptide unit, a novel chiral tripodal ligand P as an analogue of desferrichrome, has been synthesized. In neutral pH, ligand P formed stable tri(hydroxamato)-iron(Ⅲ) complexes which showed a maximum absorption (εmax=2750 M-1 cm-1) at 422 nm in UV-Vis spectra. The characteristic absorption spectra are similar to those of natural trihydroxamate-type siderophores.
Phase Transfer Catalyzed Synthesis of 1, 2-Bis[(3-aryl)-s-triazolo-[3, 4-b]-[1, 3, 4]thiadiazole-6-yl]ethanes
De Jiang LI , He Qing FU
2006, 17(6): 755-756
[Abstract](178) [FullText HTML] [PDF 103KB](1)
A series of new 1, 2-bis[(3-aryl)-s-triazolo[3, 4-b]-[1, 3, 4]thiadiazole-6-yl]ethanes were synthesized in 50-82% yield by cyclization of 3-aryl-4-amino-5-mercapto-1, 2, 4-triazole with butanedioic acid in the presence of POC13 and tetrabutylammonium iodide as phase transfer catalyst.
A Facile Stereospecific Synthesis of 1, 3-Enynylsulfides via Sonogashira Coupling of (E)-α-Iodovinyl Sulfides with 1-Alkynes
Jian Wen JIANG , Ming Zhong CAI
2006, 17(6): 757-760
[Abstract](178) [FullText HTML] [PDF 163KB](0)
(E)-α-Iodovinyl sulfides 1 underwent the Sonogashira coupling reactions with terminal alkynes 2 in piperidine at room temperature in the presence of 5 mol% of Pd(PPh3)4 and 10 mol% of CuI to afford the corresponding 1, 3-enynylsulfides 3 stereospecifically in high yields.
Total Synthesis of N-Methylsansalvamide A
Shou Xin LIU , Yan Lou GENG , Xia TIAN , Xiao Li ZHEN , Jian Rong HAN
2006, 17(6): 761-764
[Abstract](177) [FullText HTML] [PDF 145KB](0)
Total synthesis of N-methylsansalvamide A was accomplished in solution phase by a convergent approach. An N-Boc-tri-depsipepide 6 and a dipeptide ester 10 were prepared in the yield of 89% and 91%, respectively. Cyclization of the linear penta-depsipetide was achieved with PyBOP and DIPEA in DMF-CH2Cl2.
Convenient and One-pot Method for Synthesis of the Aminomethylene Bisphosphonic Acid Derivatives from Aldehydes
Xiang Zhu ZHANG , Ming Shu WU , You HUANG , Ru Yu CHEN
2006, 17(6): 765-768
[Abstract](193) [FullText HTML] [PDF 93KB](0)
Simple, efficient and convenient synthesis of aminomethylene bisphsophonic acid derivatives in one-pot reaction using aldehydes, hydroxylamine hydrochloride, phosphours trichloride and water as starting materials in the presence of pyridine was described.
The Mechanism on Cyclization, Debenzylation and Oxidation of 1-[1-(Benzyloxy)-3-methylnaphthalen-4-yloxy]propan-2-one
Shi Liang HUANG , Yi LUO , Zhi Shu HUANG , Xian Zhang BU , Pei Qing LIU , Lin MA , Yue Ming LI , Albert S. C. CHAN , Lian Quan GU
2006, 17(6): 769-772
[Abstract](187) [FullText HTML] [PDF 87KB](0)
1-[1-(Benzyloxy)-3-methylnaphthalen-4-yloxy]propan-2-one (1a) took place a cyclization, debenzylation and oxidation to form 9-substitued benzo[de]chromene-7, 8-dione (2a) and5-benzyl-9-substitued benzo[de]chromene-7, 8-dione (3a). The mechanisms for these reactions were discussed.
Three New Xanthones from Polygala crotalarioides
Yan HUA , Chang Xiang CHEN , Yu Qing LIU , Shu Kun CHEN , Jun ZHOU
2006, 17(6): 773-775
[Abstract](176) [FullText HTML] [PDF 37KB](0)
Three new xanthones, 3, 6-dihydroxy-1, 2, 7-trimethoxyxanthone 1, 1, 3, 6-trihydroxy-2, 7, 8-trimethoxyxanthone 2, and 3, 6-dihydroxy-1, 2, 7, 8-tetramethoxyxanthone 3, were isolated from the roots of Polygala crotalarioides. Their structures were elucidated by spectral and chemical methods.
Two New Bisabolane Sesquiterpenes from Leontopodium longifolium
Ji Xin LI , Xiu Ping YANG , Zhong Jian JIA
2006, 17(6): 776-778
[Abstract](176) [FullText HTML] [PDF 95KB](0)
Two new bisabolane sesquiterpenes were isolated from the roots of Leontoptdium longifolium. Their structures were elucidated as 4α, 5α-diacetoxy-1α-angeloyloxybisabol-2, 9, 11-triene and 4a, 5a-diacetoxy-1α-angeloyloxy-11-hydroxybisabol-2, 9-diene by spectroscopic methods including the 2D NMR techniques.
Indole Alkaloids from the Roots of Ervatamia hainanensis
Jian Peng HUANG , Zi Ming FENG , Chong Fei ZHENG , Pei Cheng ZHANG , Yang Min MA
2006, 17(6): 779-782
[Abstract](203) [FullText HTML] [PDF 132KB](2)
Two new indole alkaloids, named ibogamine-18-carboxylic acid, 3, 4-didehydro-7, 8-dioxo-methyl ester 1, ibogamine-18-carboxylic acid, 16, 17-didehydro-9, 17-dihydro-9-hydroxy-(2-oxopropyl)-methyl ester 2, were isolated from Ervatamia hainanensis. Their structures were elucidated on the basis of spectroscopic methods.
Alkaloids from Stems of Ervatamia yunnanensis (Ⅱ)
Shuang LIANG , Xin Gen LUO , Hai Sheng CHEN , Xiao Dong ZHANG , Mao HUANG , Wen Yong LIU
2006, 17(6): 783-786
[Abstract](167) [FullText HTML] [PDF 63KB](0)
Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis. Among them, 10-hydroxy-19, 20-dihydroisositsirikine () is new. The other five are known alkaloids, namely: matrine (), 19, 20-dihydroisositsuikine (), 19-s-voacangarine (), 11'-methoxyl-19s-heyneanine (), conodurine (Ⅵ). The structural elucidation of the alkaloids was based on spectral means.
Enantioseparation of Aminoglutethimide by High-speed Counter current Chromatography Using Carboxymethly-β-cyclodextrin as Chiral Selector
Ping AI , Jia Chuan LIU , Min ZI , Zhi Hua DENG , Zhi Hong YAN , Li Ming YUAN
2006, 17(6): 787-790
[Abstract](178) [FullText HTML] [PDF 65KB](0)
Enantioseparation of aminoglutethimide was performed by high-speed counter-current chromatography with a two-phase system composed of ethyl acetate: methanol: water=10:l:9.The lower phase contained 20 mmol/L of carboxymethly-β-cyclodextrin as chiral selector. The enantiomers were separated in 1.2 h and identified by chiral HPLC. This method was very efficient for the chiral preparative separation.
In situ High-pressure NMR Observations on the Formation and Dissociation of Methane Hydrate
Ai Bing CHEN , Wei Ping ZHANG , Xi Jie LAN , Heng ZHENG , Xiu Mei LIU , Xiu Wen HAN , Xin He BAO
2006, 17(6): 791-794
[Abstract](181) [FullText HTML] [PDF 191KB](0)
A home-made static NMR cell with pressure up to 10 MPa was employed to observe the formation and dissociation processes of methane hydrate by in situ 1H and 13C NMR spectroscopies. Methane hydrate can be formed or decomposed in the temperature range of -5 to -13℃ at pressures between 4.0 and 7.0 MPa. The higher methane pressure, the formation or dissociation temperature of methane hydrate was higher. In situ 1H NMR experiments indicated that the critical size of the hydrate clusters is crucial for the formation of methane hydrate.
Gold Nanoparticle-based Layer-by-Layer Enhancement of DNA Hybridization Electrochemical Signal at Carbon Nanotube Modified Carbon Paste Electrode
Li Bo NIE , Jian Rong CHEN , Yu Qing MIAO , Nong Yue HE
2006, 17(6): 795-798
[Abstract](189) [FullText HTML] [PDF 45KB](0)
Colloid gold nanoparticle-based layer-by-layer amplification approach was applied to enhance the electrochemical detection sensitivity of DNA hybridization at carbon nanotube modified carbon paste electrodes (CNTPEs). Streptavidin was immobilized onto the surface of CNTPEs, and the conjugation of biotin labeled target oligonucleotides to the above immobilized streptavidin was performed, followed by the hybridization of target oligonucleotides with the gold nanoparticle-labeled DNA probe and then the layer-by-layer enhanced connection of gold nanoparticles, on which oligonucleotides complementary to the DNA probe were attached, to the hybridization system. The differential pulse voltammetry (DPV) signal of total gold nanoparticles was monitored. It was found that the layer-by-layer colloidal gold DPV detection enhanced the sensitivity by about one order of magnitude compared with that of one-layer detection. One-base mismatched DNA and complementary DNA could be distinguished clearly.
A New Protocol for Solubilization, Refolding and Purification of Recombinant Human Granulocyte Colony-stimulating Factor in Inclusion Bodies
Jia Hua LIU , Chao Zhan WANG , Xin Du GENG
2006, 17(6): 799-802
[Abstract](175) [FullText HTML] [PDF 107KB](0)
Recombinant human granulocyte colony-stimulating factor (rhG-CSF) in inclusion bodies was solubilized by 8 mol/L urea solution and subsequently precipitated by acetone to improve its purity. After that, the precipitates were solubilized by sodium hydroxide solution containing 2 mol/L urea. Then the solubilized rhG-CSF was passed through a size exclusion chromatography for refolding and extensive purification, and further purified by a weak anion exchange chromatography. The purity and mass recovery of refolded rhG-CSF were 96.5% and 75.6%, respectively. The bioactivity was 8.4×107 IU/mg.
Pt Complexes with High Molecular Weight Polyvinylmethyldimethylsiloxane Ligands Supported on Diatomite for Liquid-phase Hydrosilylation of 3, 3, 3-Trifluoropropene with Methyldichlorosilane
Hong Liu LIAO , Huai Jun ZHU , Feng Yi LI
2006, 17(6): 803-806
[Abstract](185) [FullText HTML] [PDF 93KB](0)
Pt complexes with high molecular weight polyvinylmethyldimethylsiloxane (HMPVMS)ligands supported on diatomite as a catalyst for the hydrosilylation of 3, 3, 3-trifluoropropene and methyldichlorosilane. Results show that this catalyst displays good thermal stability, high activity and excellent recyclability, and it can be readily fabricated by a simple process.
Enantioseparation of Dencichine and D-Isomer on L-Cysteine Derivative Phase by Ligand-exchange Chromatography
Yan Shun MA , Qing Hua MENG , Hong Yu SHI , Yuan De LONG , Tian Bao HUANG
2006, 17(6): 807-808
[Abstract](195) [FullText HTML] [PDF 109KB](0)
The enantioseparation of dencichine and its D-isomer was achieved on a novel chiral stationary phase via coating N-(2-hydroxyl-3-octoxyl) propyl-S-benzyl-(L)-cysteine on YWG-C18phase by ligand exchange chromatography.
Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier
Zhi Hua WANG , Min CAI , Shu Jun WANG
2006, 17(6): 809-812
[Abstract](185) [FullText HTML] [PDF 60KB](0)
The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry (FAAS) were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5μg.mL-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%-101%, thesensitivity is 0.19μg·mL-1, and deyection limit is 77 ng·mL-1, The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.
Rapid Preparation of Monolithic Columns for Capillary Electrochromatography Separation
Wen Jun GONG , Yi Jun ZHANG , Yu Ping ZHANG , Seong Ho CHOI
2006, 17(6): 813-816
[Abstract](173) [FullText HTML] [PDF 174KB](0)
Fritless packed silica gel columns were prepared using sol-gel technology. The part of a 75μm i.d. capillary was filled with a mixture of methacryloxypropyltrimethoxysilane, toluene and hydrochloric acid. Four different photoinitiators such as benzoin methyl ether, Irgacure 819, Irgacure 1700 and irgacure 1800 were added in the presence or absence of sodium dodecyl sulfate during the polymerization process. The above eight solutions were irradiated at 365 nm about 5-10 min to prepare the porous monolithic sol-gel columns by a one-step process.
An Unprecedented 1D Zigzag Chain Alkaline Earth Metal Derivative {[Ba(DMF)3(H2O)2][Ba(DMF)4]2(P2W18O62)}n Containing Dawson Heteropolyanion
Jing Ping WANG , Jian Ru MA , Jing Yang NIU
2006, 17(6): 817-820
[Abstract](175) [FullText HTML] [PDF 182KB](0)
:An unprecedented 1D zigzag chain alkaline earth metal derivative, {[Ba(DMF)3(H2O)2][Ba(DMF)4]2(P2W18O62)}n, (DMF=N, N-dimethyl formamide) containing Dawson heteropolyanion has been successfully synthesized and characterized by X-ray crystallography. Two barium cations bridged by three DMF ligands in parallel combination with the Dawson-type heteropolyanion [P2W18O62]6- and then the resulting subunits {[Ba(DMF)4]2(P2W18O62)}2+ are alternately linked together via another [Ba(DMF)3(H2O)2]2+ ions, constructing a 1D zigzag chain architecture.
Synthesis and Crystal Structure of a Novel Diorganotin(Ⅳ) Complex Containing 3, 4-Difluorobenzohydroxamato Ligand
Xian Mei SHANG , Ji Zhou WU , Qing Shan LI
2006, 17(6): 821-824
[Abstract](176) [FullText HTML] [PDF 177KB](1)
A new five-coordinate mixed-ligand compound, di-n-butyl(3, 4-difluorobenzoxy)-(3, 4-difluorobenzohydroxamato)tin(Ⅳ) 1 was synthesized and characterized by IR, 1H, 13C, 119Sn NMR spectra and single crystal X-ray diffraction technique.
Controlled Synthesis and Electrochemical Behavior of Single-crystal MoO2 Nanowhiskers by a Facile Precursor-reduction Route
Yu Mei KONG , Jun PENG , Feng Shan SHEN , Bao Xia DONG , Li LI
2006, 17(6): 825-828
[Abstract](153) [FullText HTML] [PDF 179KB](0)
A novel method for controlled synthesis of crystalline molybdenum dioxides nanowhiskers (whisker-MoO2) by using moderate reductive and precursor ion under hydrothermal conditions is reported. The result shows that the as-obtained samples have a monoclinic structure, and the whisker-MoO2 is composed of nanowires with diameters of ca. 20 nm. Formation of whisker-MoO2 was through a typical precursor-reduction process, in which cetyltrimethylammonium bromide (CTAB) served as a cationic surfactant and acetone as a reductant. The electrochemical behavior of whisker-MoO2 was studied.
Preparation of Near IR Reflective Materials via Hollow Ballotini Enwrapped by TiO2
Cheng Yin MA , Ping Sheng TANG , Yan Sheng LI
2006, 17(6): 829-832
[Abstract](191) [FullText HTML] [PDF 196KB](1)
Near IR reflective functional material was made via hollow ballotini enwrapped by TiO2 according to IR reflective principles. Metatitanic acid covers on the surface of hollow ballotini through electrostatic attraction as pH is less than 2.5. The results of SEM and XRD spectrum show that TiO2 enwraps hollow ballotini well and the crystal form is anatase. When TiO2 covering thickness is below 0.5μm, reflectance swells along with the increase of thickness, whereas above 0.5μm it keeps stable. Coatings made from mixing enwrapped HB with styrene-acrylic latex were coated on aluminum foil, and reflectances were mensurated. It is found that reflectance keeps stable when the coating can wrap the base and reflectances of the coating in visible range and in near IR range are 86% and 81%, respectively.
A New Route for Preparation of β-TCP/PLLA Composite
Feng ZHANG , Fang MEI , Xin Zhi WANG , Xiao Yang HU , Yong Ming LUO , Xu Liang DENG
2006, 17(6): 833-836
[Abstract](183) [FullText HTML] [PDF 532KB](0)
A new facile route for preparation of β-TCP/PLLA composites is reported in this letter.SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse.Two months later histological examination showed that new collagen and new dentin formed.The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation, offering a new way to dental tissue engineering.
Study on Thermosensitive Micellization of Dextran-g-PNIPAAm in Aqueous Solutions
Dan ZHAO , Li Qun WANG , Ke Hua TU , Song Wei TAN
2006, 17(6): 837-840
[Abstract](184) [FullText HTML] [PDF 365KB](0)
The thermosensitive micellization of dextran-g-PNIPAAm in aqueous solutions has been investigated by fluorescence spectroscopy, dynamic light scattering and transmission electron microscope. The formed polymeric micelles showed different diameters of about 20 nm or 100nm, when the solution temperature was below or above the phase transition temperature.
Enhanced Acid/Base Catalysis in High Temperature Liquid Water
Xiu Yang LU , Qi JING , Zhun LI , Lei YUAN , Fei GAO , Xin LIU
2006, 17(6): 841-844
[Abstract](191) [FullText HTML] [PDF 63KB](1)
Two novel and environmentally benign solvent systems, organic acids-enriched high temperature liquid water (HTLW) and NH3-enriched HTLW, were developed, which can enhance the reaction rate of acid/base-catalyzed organic reactions in HTLW. We investigated the decomposition of fructose in organic acids-enriched HTLW, hydrolysis of cinnamaldehyde and aldol condensation of phenylaldehyde with acetaldehyde in NH3-enriched HTLW. The experimental results demonstrated that organic acids-enriched or NH3-enriched HTLW can greatly accelerate acid/base-catalyzed organic reactions in HTLW.
Self-assembly of Gold Nanoparticle Chains between Nanoelectrodes
Ning GU , Jian Hui LIAO , Lan HUANG , Zhi Rui GUO , Wei YU , Li Na XU , Jing WANG
2006, 17(6): 845-847
[Abstract](178) [FullText HTML] [PDF 90KB](1)
A novel strategy has been developed for construction of nanoparticle chains between nanoelectrodes with bifunctional molecules by taking advantage of linear aggregation of colloidal particles in organic solvents. As confirmed by scanning electron microscopy (SEM), an individual nanoparticle chain bridged the electrode pair. The present approach makes this technique to be cheap and may be applicable in microelectronic industry.
Heteropolymolybdate as a New Reaction-controlled Phase-transfer Catalyst for Efficient Alcohol Oxidation with Hydrogen Peroxide
Zhi Huan WENG , Jin Yan WANG , Xi Gao JIAN
2006, 17(6): 848-850
[Abstract](174) [FullText HTML] [PDF 57KB](0)
A new catalytic process for the synthesis of aldehyde from alcohol by oxidation with H2O2 with high selectivity was studied. In this system, heteropolymolybdate [C7H7N(CH3)3]3{PO4[MoO(O2)2]4} was utilized as the reaction-controlled phase-transfer catalyst to catalyze oxidation of benzyl and aliphatic alcohols. The molar ratio of H2O2 and alcohol was 0.75, no other by-products were detected by gas chromatography, the results of oxidation reaction indicated that the catalyst has high activity and stability.
Computational Evidence for the Smallest Boron Nanotube
Xian Jie LIN , Dong Ju ZHANG , Cheng Bu LIU
2006, 17(6): 851-852
[Abstract](189) [FullText HTML] [PDF 53KB](0)
The structure of boron nanotubes (BNTs) was found not to be limited to hexagonal pyramidal structures. Based on density functional theory calculations we provided evidence for the smallest boron nanotube, a geometrical analog of the corresponding carbon nanotube. As shown by our calculations, the smallest BNT possesses highly structural, dynamical, and thermal stability, which should be interest for attempts at its synthesis.
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