bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical reduction process of bilirubin in dimethylformamide
Authors: Niu Jian‐Jun , Dong Shao‐Jun
Published: September 2010

The electrochemical reduction behavior of bilirubin (BR) at platinum electrode in DMF wag investigated by cyclic voltammetry, in situ electron spin resonance spectroscopy and in situ rapid scanning thin layer spectroelectrochemistry. Experimental results revealed that the reduction of BR firstly undergoes an ECE process: magnified image. The generated (BR)3−2 can be re‐oxidized to BR and then to purpurin (Pu) by a series of oxidation processes: magnified image. However, the re‐reduction reactions of Pu are not the reverse processes. The different reduction mechanisms are discussed in detail.
Chemical synthesis of a structural gene coding for trichosanthin
Authors: Chen Hai‐Bao , Xia Yi , Jing Jun‐Ping , Jiang Kun , Bao Jian‐Shao
Published: September 2010

A structural gene (750 bp), which codes for a type 1 ribosome inactivating protein, trichosanthin, has been designed according to the codon usage of highly expressed gene in E. coli and chemically synthesized. In the synthesized gene, twenty‐seven unique restriction sites were evenly dispersed with an average distance between two adjacent sites less than 50 bp to facilitate a systematic investigation on structure‐functional relationship of this protein by she‐directed mutagenesis. To synthesize it, the whole gene was divided into three large fragments (EP, PN and NH) which were assembled from several chemical synthetic oligonucleotides by enzymatic method. The assembly of both the fragment BP from six oligonucleotides (A‐F) and the fragment PN from four oligomers (G‐J) was catalysed by T4 DNA ligase in using the single stranded DNA method [Chen, H.‐B. et al., Nucl. Acids Res., 18, 871(1990)]. And fragment NH was formed from three duplexes K, L and M by the classical double stranded DNA method. Finally, each fragment was cloned into vector pUC18 in succession to form the plasmid, pC0TCS, to complete the whole gene synthesis. The sequencing data for the synthetic gene coincides with the designed one.
Comparison between hydrogen‐transfer and fluoro‐transfer reactions on the microcanonical unimolecular rate constants
Authors: Feng Wen‐Lin , Zhang Shao‐Wen , Wang Yan , Wu Jun‐Nan , Li Zong‐He
Published: September 2010

The microcanonical rate constants for the hydrogen‐transfer process of HCCF (reaction 7) and the fluoro‐transfer process of FCCF (reaction 8) are carried out with tunneling correction and curvature correction. The results show that the tunneling effects and curvature effects on the rate constant of reaction 7 is quite different from that of reaction 8. The rate constants for different rotational states are also studied for these reactions.
Staircase pulse voltammetry
Authors: Mo Jin‐Yuan , Chen Shao‐Hua , Zou Youg‐De , Cai Pei‐Xiang
Published: September 2010

The faradaic current of interest can often be obscured by some extraneous current. A new method called staircase pulse voltammetry (SPV), with which involving a potential pulse is superimposed on a staircase, is used for removing the double‐layer charging current This paper presents the theoretical consideration and the experimental evidence of this method for a simple reversible system and a catalytic process. The parameters affecting currents are also discussed. Experimental verifications are in agreement with the theories.
Enhancement of intramolecular excimer formation and photodimerization of anthrylmethyl α,ω‐alkanedioates via hydrophobic interactions
Authors: Tung Chen‐Ho , Li Yi
Published: September 2010

The fluorescence spectra and photodimerization of anthrylmethyl α,ω‐alkanedioates (A‐Mn‐A; both in organic and in aqueous organic mixed solvents have been studied. In aqueous organic mixed solvents strong intramolecular excimer emission is detected and the quantum yield for the intramolecular photodimerization is significantly greater than those in organic solvents. These observations suggest that hydrophobic interactions force A‐Mn‐A molecule to self‐coil. The ratio of the head‐to‐head to head‐to‐tail products in the intramolecular photodimers of A‐Mn‐A depends on the length of the linking chain. This work presents a successful example of application of hydrophobic interactions to enhancement of large‐ring formation.
Structural study on a bioactive fructan from the root of Achyranthes bidentata Blume
Authors: Yu Biao , Tian Geng‐Yuan , Hui Yong‐Zheng
Published: September 2010

The structure of a saccharide component (Abs), with pronounced activity of improving immunity system, isolated from the root of Achyranthes bidentata Blume, a traditional Chinese herbal medicine, was studied. Based on 13C NMR, HPLC, and methylation analyses, Abs was shown to be a mixture of short‐chain fructans with an average dp of8, containing more (2→6) than (2→l) linked β‐D‐fructofuranosyl residues, with branching at O‐6 or O‐1 of 18% of the D‐fructofuranosyl residues.
Syntheses of fluoroalkyl derivatives of two biologically active oligopeptides
Authors: Li Rui‐Qing , Huang Wei‐Yuan
Published: September 2010

Fluoroalkyl derivatives of two biologically active oligopeptides (m‐CF3)Tyr1j‐Leu‐enkephalin. [(m‐C2F4Cl)Tyr1]‐Leu‐enkephalin and [(m‐COCF2Cl)Tyr2]‐melanocyte‐stimulating hormone releasing hormone have been synthesized. Studies on the activities of these peptides are underway.
Synthesis of dinucleoside, di(2′‐deoxy‐2′‐fluoro)nucleoside phosphates and phosphorothioates and their stability to snake venom phosphodiesterase
Authors: Zheng‐Fu Wang , Xiao‐Hui Gu , Yao‐Quan Chen
Published: September 2010

Dithymidine, di(2′‐deoxy‐2′‐fluoro)‐cytidine and ‐uridine phosphate and phosphorothioate have been synthesized. The stereochemistry of the condensation reaction between 2′‐deoxy‐2′‐fluoronucleoside phosphoramidite and nucleoside was preliminarily investigated. The diastereomer separation of the protected phosphorothioates was performed by silica gel column chromatography. The stability of these compounds to snake venom phosphodiesterase was determined.
A study on some macrocyclic bicopper(II) complexes as the model compounds of superoxide dismutase
Authors: Wen Qian , Guang‐Quan Mei , Qin‐Hui Luo
Published: September 2010

24‐Membered macrocyclic bicopper(II) complexes wth bridging ligand imidzaolate, SCN−, N3− and H2O respectively were synthesized by condensation of diacetylpyridine with 3‐oxapentane‐1,5‐diamine. As the model compounds of superoxide dismutase (SOD), the relationship between their SOD activities and properties of bridging ligands and redox potentials of copper(II) were studied.
Determination of isoniazid and hydrazine by capillary electrophoresis with amperometric detection at a Pt‐particle modified carbon fiber microelectrode
Authors: Er‐Kang Wang , Wei‐Hong Zhou
Published: September 2010

Capillary electrophoresis (CE)/electrochemical detection (EC) for the simultaneous determination of hydrazine and isoniazid has been developed. The electrochemical method uses a novel modified electrode dispersed with ultrafine platinum particles on the surface of a 30 μm carbon fiber microelectrode. The unique characteristic of the Pt‐particles modified carbon fiber microelectrode is its excellent stability. The current measurement for hydrazine is more sensitive than that of isoniazid. Selective determination of trace amount of free hydrazine in isoniazid and its formulation can be achieved at applied potential of 0.5 V.
Asymmetric total syntheses of (+)‐goniopypyrone and (+) ‐ 9‐ deoxygoniopypyrone
Authors: Zhi‐Cai Yang , Wei‐Shan Zhou
Published: September 2010

Asymmetric total syntheses of (+)‐goniopypyrone (1) and (+)‐deoxygoniopypyrone (2) from methyl cinnamate (7) via (DHQ)2‐PHAL‐OsO4 catalyzed asymmetric dihydroxylation and highly stereoselective 2‐furylcopper addition in eight steps and eleven steps with overall yield of 20% and 13%, respectively, are described.
Supramolecular assemblies from single‐chain hydrocarbon fluorocarbon hybrid bolaamphiphiles
Authors: Biao Yu , Yong‐Zheng Hui
Published: September 2010

Three types of single‐chain hydrocarbon fluorocarbon hybrid bolaamphiphiles were synthesized. They readily formed different kinds of organized supramolecular assemblies, including vesicles, tapes, and micellar fibers, in aqueous solution. The aggregates morphology was characterized by transmission electron microscopy (TEM) after negative staining. The superstructures of these aggregates seemed to be determined by the geometry and the head group's properties of the corresponding amphiphiles.
Thermodynamic parameters of interaction of HCl with alcohols in water III. HCl‐ethanol‐water system at 278.15–318.15 K
Authors: Ke‐Lei Zhuo , Jian‐Ji Wang , Wen‐Bin Liu , Jin‐Suo Lu
Published: September 2010

The emfs of cells without‐junction Pt, H2(g, p0)|HCl(mE)|AgCl‐Ag
Studies of a new series of ion‐pair complexes [Mo(dtc)4][Ln(dtc)4] (Ln = La‐Er, exp. Pm)
Authors: Qing‐Hong Fu , Guang‐Ren Zhang , Chun‐Ting Sun , Shu‐Yun Niu , Li‐Xin Wu
Published: September 2010

A new series of ion‐pair complexes [Mo(dtc)4] [Ln(dtc)4] (LnLa‐Er, exp. Pm) were synthesized from MoCl5, LnCl3 and Nadtc in anhydrous methanol. The crystal structures of the four complexes, [Mo(dtc)4J[Ln(dtc)4] (LnNd, Sm, Ho and Er) have been determined by X‐ray diffraction. Spectroscopic properties of all these complexes are also discussed here.
Effect of Sb on the properties of anodic Pb(II) oxide film formed in alkaline solution
Authors: Qun‐Zhou Wang , Gang Liu , Hou‐Tian Liu , Wei‐Fang Zhou
Published: September 2010

The composition and properties of the anodic films formed on Pb and Pb‐3at. %Sb alloy at ‐0.10 V (vs. Hg/HgO) for 2.5 h in 0.1 mol·dm−3 NaOH solution (25°C) were investigated by cyclic voltammetry, linear sweep voltammetry, open circuit decay curve, photocurrent technique, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the anodic film formed on Pb mainly consists oft‐PbO, while that on Pb‐3at.%Sb consists of o‐PbO, t‐PbO and a small amount of orthorhombic Sb2O3. The dominant component of the film anodically grown on Pb‐3at.%Sb for less than 5 min is o‐PbO, however, t‐PbO is the major component of the anodic film formed for 1 h or longer. It is established that Sb suppresses the growth of t‐PbO. The anodic film formed on Pb‐3at.%Sb is less porous than that on Pb. The bandgap energies of t‐PbO and o‐PbO in the films were determined by photocurrent measurements to be 1.83–1.84 eV and 2.60 eV, respectively.
Oxyfunctionalization of ketones bearing α‐methylene group with piperidine oxoammonium salt. Synthesis of α‐diketones from monoketones
Authors: You‐Cheng Liu , Tan Ren , Qing‐Xiang Guo
Published: September 2010

A facile method for the title transformation is described. The reaction of 2,2,6,6‐tetramethyl‐4‐methoxypiperidine oxoammonium chloride (1b) and ketones bearing α‐methylene group in acetonitrile proceeded smoothly to give the α‐oxyfunctionalized coupling products (6a‐h). These coupling products decomposed upon heating in acidic medium to produce α‐diketones (7a‐h) in good to excellent yields.
Synthesis of 2‐aryl‐3H‐indol‐3‐ones via trapping reaction in singlet oxygenation of 2‐arylindoles
Authors: Ke‐Qing Ling
Published: September 2010

2‐Aryl‐3H‐indol‐3‐ones (3a‐o) have been synthesized via methanol trapping reaction in singlet oxygenation of 2‐arylindoles (1a‐o), followed by thermal decomposition of the resultant 2‐aryl‐2‐methoxy‐3‐oxo‐2,3‐dihydroindoles (2a‐o) in good yields.
Theory and application of cyclic voltammetry for measurement of fast electrode kinetics at microdisk electrode,
Authors: Bao‐Kang Jin , Jian‐Rong Zhang , Zu‐Xun Zhang
Published: September 2010

An analytical expression describing voltammetric behaviors responses at microdisk electrode for various diffusion conditions and degrees of reversibility is reported in this paper. Results of theoretical calculation made it possible to use cyclic voltammetry to evaluate heterogeneous rate constants under intermediate diffusion conditions. At relatively low scan rate, the distortion of current‐voltage can be reduced due to small iR drops and charging current. The effects of transfer coefficient, α, kinetic parameter, λ(=k0r/4D), and switching potential, εs, on potential peak separation are discussed in detail. The relationship obtained in this paper between potential peak separation and λ is in good agreement with that in Ref. 14, whose authors have got their results by using digital simulation technique. After the experiment of Fe(CN)4–6 oxidation, k0 and α were obtained by the theory of this paper. The result agrees with that in Ref. 19.
Enantiomeric separation of α‐phenylethylamine and its analogs by mixed chiral and achiral stationary phase
Authors: Liang‐Mo Zhou , Xue‐Liang Liu , Zhong‐Sheng Li , Qing‐Hai Wang , Dao‐Qian Zhu , Dong‐Hong Hu
Published: September 2010

A mixed stationary phase of modified β‐cyclodextrin, 2,6‐di‐O‐butyl‐3‐O‐butyryl‐β‐cyclodextrin (phase A), and SE‐54 (phase B) was used for enantiomeric separation of α‐phenylethylamine,o,m,p‐methyl ando,m,p‐methoxy‐substituted analogs. The composition of mixed phase was selected by comparison of each calculated αmin(=(γm,i+1)/(γm,i)), the relative retention values of the most adjacent peaks, and γm, last, the relative retention values of the last eluting peak at each preselected ratio. Values of γ,i, a calculated by derived equations were in good agreement with the experimental results obtained with two specified mixed phases. All solutes investigated were almost baseline separated at a predicted composition of phase A and phase B in a single run within 18 minutes.
Studies on sulfinatodehalogenation: The reaction of polyfluoroalkyl iodides and bromides with sodium Bisulfite
Authors: Fan‐Hong Wu , Bing‐Nan Huang , Wei‐Yuan Huang
Published: September 2010

Without oxidant, sodium bisulfite reacted with polyfluoroalkyl iodides and bromides in aqueous DMF solution to give the corresponding sulfinates in good yields.
The band structures of some transition metals and their NaCl‐type compounds
Authors: Shu‐Hui Cai , Chun‐Wan Liu
Published: September 2010

The band structures of Group IVB (Ti, Zr, Hf), VB (V, Nb, Ta) and V1B (Cr, Mo, W) transition metals and some of their carbides and nitrides (TiN, ZrN, HfN, VC, NbC, TaC, VN, NbN, TaN) with NaCl‐type (Bl‐type) structure have been calculated by using the tight‐binding method within the Extended Hückel approximation (EHT). The energy bands, densities of states and crystal orbital overlap populations are given. The relationship between the bonding properties and the superconducting transition temperatures (Tc) of them is discussed. The influences of various kinds of metallic atoms and changes of bond lengths on Tc are also discussed.
Solvent effects on competitive intramolecular electron transfer and energy transfer in a covalently linked porphyrin‐phthalocyanine heterodimer
Authors: Hong‐Jian Tian , Qing‐Pu Zhou , Shu‐Yin Shen , Hui‐Jun Xu
Published: September 2010

Photophysical properties of a porphyrin‐phthalocyanine heterodimer covalently linked with a dipentoxy chain have been studied. Absorption spectra show that there is weak exciton coupling between the two chromophores in the ground state. Fluorescence spectra show that intramolecular energy transfer from porphyrin to phthalocyanine moiety occurs in competition with electron transfer. The efficiency of these two processes depends upon the mutual orientation of the two chromophores. The effect of solvent polarity on the intramolecular processes is also discussed.
Synthesis, characterization, antitumor activity of nickel(II) and cobalt(II) complexes of 2,2′‐diamino‐4,4′‐bithiazole and their interaction with dGMP
Authors: Yan‐Ni Tian , Pin Yang , Qing‐Shan Li , Chun‐Gui Zhao
Published: September 2010

New complexes, of bis(2,2′‐diamino‐4,4′‐bithiazole)sulfate nickel(II) and bis(2,2′‐diamino‐4,4′‐bithiazole)sulfate cobalt(II), have been prepared. The complexes were characterized by infrared and UV‐Vis spectroscopy, 1H NMR, elemental analyses and molar conductivity. The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation. The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells. In order to provide a molecular basis for understanding the biological effects, the probe, [trans‐en2Os(2‐H2)](CF3SO3)2 (en, ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2′‐deoxyguanosine‐5′‐monophosphate (dGMP).
Synthesis and reactions of 2‐[α‐(3,4‐disubstituted phenacyl)‐p‐substituted styryl]‐4H‐3,1‐benzoxazin‐4‐ones
Authors: Ahmed Youssef Soliman , Ibrahim Abd El‐Mogoud Attia , Moneer Abdu Ibrahim Salem , El‐Sayed Ahmed Soliman , Adel Mohy El‐Deen Gaber
Published: September 2010

Conversion of β‐aroyl propionic acids into furanone derivatives (2) and benzoxazinone derivatives (3) for the study of the reactivity of these nucleus towards different nucleophilic and electrophilic reagents.
Syntheses of a new type of chiral phosphines from glucose
Authors: Ji‐Cheng Shi , Ting‐Bin Wen , Da‐Xu Wu , Ge‐Tan Lu , Mao‐Chun Hong , Qiu‐Tian Liu , Bei‐Sheng Kang , Han‐Qing Wang , Shi‐Jie Lü
Published: September 2010

Methyl 3‐deoxy‐3‐(diphenylphosphino)‐4,6‐O‐benzylidene‐α‐D‐altropyranoside (1) and methyl 2‐deoxy‐2‐(diphenylphosphino)‐4,6‐O‐benzylidene‐α‐D‐altropyranoside (2) were prepared from methyl 2,3‐anhydro‐4,6‐O‐benzylidene‐O‐D‐mannopyranoside and methyl 2,3‐anhydro‐4,6‐O‐benzylidene‐α‐D‐allopyranoside, respectively, via regioselective and stereospecific ring‐opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (S and 4).
A Barbier type reaction promoted by in situ formed active metal bismuth from NaBH4 and BiCl3 in aqueous media
Authors: Ping‐Da Ren , Shi‐Feng Pan , Ting‐Wei Dong , Shi‐Hui Wu
Published: September 2010

In the presence of active metal bismuth (Bi*) which was prepared from the combination of bismuth trichloride and sodium borohydride, aldehydes have been found to react with allyl bromide in aqueous media, and the corresponding homoallylic alcohols were obtained in excellent yields with high chemo‐and stereoselectivity.
Photochemical reaction of azobenzene in solvent‐swollen Nafion membranes
Authors: Chen‐Ho Tung , Jing‐Qu Guan
Published: September 2010

The photochemical reactions of azobenzene (AB) incorporated into different solvent‐swollen Nafion membranes were investigated. The location of azobenzene in water‐swollen Nafion membranes was different from that in methanol‐swollen Nafion membranes, which was responsible for the different photochemical reactions of AB. In methanol‐swollen Nafion membranes only trans↔cis isomerization took place, while in water‐swollen Nafion membranes photochemical cyclization of AB occurred after rapid trans↔cis isomerization. The relation between the relative quantum yields and the light intensity showed that the cyclization was a two‐photo process. The numbers of AB molecules per cluster (nAB/cluster) in Nafion membranes with different AB concentrations and different water contents were calculated. Under the experimental condition two competitive photocyclization mechanisms were suggested by nAB/cluster in Nafion membranes, relative quantum yields of the cyclization, and the change of the ratio of benzidine to benzo[c]cinnoline.
Palladium‐induced electron‐transfer reaction of difluorodiiodomethane with
Authors: An‐Rong Alkenes, Li , Qing‐Yun Chen
Published: September 2010

The addition reaction of difluorodiiodomethane (1) with alkenes in the presence of PdCl2(PPh3)2 or Pd(PPh3)4 afforded the corresponding iododifluoromethylated compounds in excellent yield.
Quantum chemical study on the thermal Diels‐Alder reaction of cyclohexadiene and methyl crotonate
Authors: Li Yong‐Hong , Hong San‐Guo , Wang Shen , Peng Yi‐Yuan
Published: September 2010

AM1 molecular orbital method using the unrestricted Hartree‐Fock(UHF) calculations has been applied to investigate the thermal reaction of cyclohexadiene and methyl crotonate. The calculated results indicate that the thermal Diels‐Alder reaction proceeds to product through the concerted path and two radical pathways.
Study on the dual‐frequency oscillations in galactose‐BZ system
Authors: Li He‐Xing
Published: September 2010

Three types of duel‐frequency oscillations in KBrO3‐galactose‐acetone‐SO4‐H2SO4 have been observed in a batch reactor depending on the initial concentration of H2SO4 or Br‐. Similar phenomena were also observed when galactose was replaced by other aldosugars such as glucose, arabinose, lactose and maltose. However no dual‐frequency oscillation has been found when ketosugar like fructose was used instead of galactose as the substrate. The roles of acidity, bromide ion and acetone in dual‐frequency oscillations have been analyzed. The mechanism of dual‐frequency oscillations has been discussed.
Mössbauer study of reactions of Sn[Fe(CN)6] on supports
Authors: Chen Shou‐Wen , Yang Xu‐Jie , Lu Lu‐De , Wang Xin
Published: September 2010

Mössbauer spectroscopy has been applied to the investigation of reaction of Sn(Fe(CN)6 on magnesia, γ‐alumina, silica and activated carbon. It wan found that the thermal decomposition products of supported Sn[Fe(CN)6] are quite different from those of the unsupported one as a result of the interaction between the complex and supports. The supports could promote the oxidation in the air atmosphere and their effect led to high dispersion of the decomposition products on the surface.
Incorporation of Fe(III) in framework of zeolite L
Authors: He Nong‐Yue , Bao Shu‐Lin , Xu Qin‐Hua
Published: September 2010

Zeolite L with Fe in lattice position is prepared from the gel with Fe/(Fe+Al) ratio up to 0.4 using ferric nitrate as Fe source. The incorporation of Fe(III) in framework is characterized by XRD, IR, TG/DTA, BET and Mössbauer spectroscopy. Zeolite L is destabilized by Fe(III) in framework and the reduction of Fe(III) in framework of (A1,Fe )KL was first reported.
Hypersensitivity and its application to structural analysis of lanthanide complexes
Authors: Yang Wu , Chen Miao , Gao Jin‐Zhang , Yang Wei‐Dong , Kang Jing‐Wan , Yang Hong‐Wu
Published: September 2010

Hypersensitivity of the ternary complexes Ln(β‐dik)4HMQ(where Ln=Nd, Ho, Er, β‐dik=acetylacetonate(AA), dibenzoylmethanate(DBM) and MQ=4‐methylquinoline) in acetone solution is studied based on the dynamic coupling model. The structures of these complexes in solution are deduced. Their coordination polyhydrons are all distorted square antiprism. Neodymium complexes have D2 symmetry, while holmium and erbium complexes have exact D2d symmetry.
A study of the quenching of PCl(b1Σ+) by the E‐V model
Authors: Liu Chuan‐Pu , Zou Sheng‐Li , Guo Jing‐Zhong , Gu Yue‐Shu , Chu Ym‐Na , Cao De‐Zhm
Published: September 2010

Using the reaction of Ar(3P0,2) + PCl3 as a source of PCl(b1Σ+), we have measured the quenching rate constants of PCl(b,v'=0) for more than 20 quenchers. The EV model is used to calculate the rate constants. The comparison of the calculated values with the experimental one shows that the quenching of PCl(b) by the reagent molecules results from the electronic to vibrational energy near resonance transfer and has been related to the Franck‐Condon factors for the PCl(b,v'=0 →a,v″=m) transition and to the anharmonicities of the terminal bonds of the quenchers. In addition, the influence of the polarizability of the reagent molecule on the quenching rate constant in discussed.
In vitro antitumor activity of titanocene alanine complex and its interaction with nucleic acids
Authors: Zhang Zhi‐Gag , Jin La , Yang Pin
Published: September 2010

Titanocene alanine complex, Cp2Ti(O2CCH(CH3)NH+3CI−)2, haa been found to have in vitro antitumor activity against Ehrlich ascites tumor cells. Study of the interaction between Cp2Ti(O2CCH(CH3)NH+3CI−)2 and DNA by UV‐VIS spectra, fluorescence spectra, agarose gel electrophoresis reveals that Cp2Ti(O2CCH(CH3)NH+3Cl−)2 form a stable compound with DNA in molar ratio 1:1 and reduces the migration rate of ccc‐DNA band and oc‐DNA band. However, unlike cis‐platin, the complex does not induce nicking of DNA even after a long incubation at a high ratio of the complex to DNA. The results suggest that titanocene‐based antitumor agents have different mechanism of action from cisplatin‐like antitumor agents.
Synthesis, luminescence properties and energy transfer of binary and ternary rare earth complexes with aromatic acids and 1,10‐phenanthroline
Authors: Yan Sing , Zhang Hong‐Jie , Ni Jia‐Zuan
Published: September 2010

A series of binary and ternary ram earth (Gd, Eu, Tb) complexes with ortho hydroxyl benzoic acid, para aminobenzoic acid, nicotinic acid and 1,10‐phenanthroline were synthesized. Phosphorescence spectra and lifetimes of Gd complexes were measured and the lowest triplet state energies of gadolinium binary complexes and the intramolecular energy transfer efficiencies were determined. The luminescence properties and energy transfer process of Eu3+and Tb3+ complexes were discussed.
A facile synthesis of per(poly)fluoroalkyl substituted α‐amino acid derivatives
Authors: Hu Qiao‐Sheng , Hu Chang‐Ming
Published: September 2010

Initiated by CrCl3/Fe redox couple, per(poly)fluoroalkyl iodides added to methyl α‐acetylamino acrylate, giving β‐per(poly)fluoroalkyl α‐amino acid derivatives in good yields.
Study on electric property at interface of positive sol of magnesium aluminum hydroxide
Authors: Han Shu‐Hua , Xu Shan‐Ping , Hou Wan‐Guo , Sun De‐Jun , Zhang Chm‐Guang , Wang Guo‐Ting
Published: September 2010

The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charge of magnesium aluminum hydroxide was composed of variable charge and permanent positive charge. Because of the permanent positive charge, the IEP and ZPC obtained were higher than calculated. The IEP decreased and ZPC increased as X increased.
Electrochemical characteristics of poly(o‐phenylendiamine) film electrodes in phosphatic solution
Authors: Ye Bao‐Xian , Zhang Wu‐Ming , Zhou Xing‐Yao
Published: September 2010

The electrochemical characteristics of poly(o‐phenylendiamine) (POPD) film modified electrodes have been investigated using different electrochemical techniques. The main interest is focused on the effect of potential and film thickness on the electrode process. Good agreement has been found for the apparent diffusion coefficient estimated by chronocoulometry and impedance spectroscopy. The charge transfer process within POPD films is diffusion processes at negative and positive overpotentials and electron hopping mechanism at formal potential. The POPD film conductivity of the oxidized state is better than that of the reduced state. For all electrode processes, the H+ may penetrate the film/electrolyte interface and take part in charge transfer or protonation‐deprotonation of phenazine rings.
Lead‐promoted Barbier‐type reaction of aldehydes with propargyl bromides in aqueous media
Authors: Zhou Jing‐Yao , Sun Guang‐Fu , Zhang Ming‐Fu , Jia Yu , Wu Shi‐Hui
Published: September 2010

This paper reports that the reaction of the propargyl bromides with aldehydes promoted by powdered lead in aqueous media. The selectivity and possible mechanism of these reactions are discussed. The yields of products for reaction of propargyl bromide are 31∼71%. The ratios of allenyl alcohol and homopropargyl alcohol are 1:1.5 to 1:3. The product for reaction of phenyl propargyl bromide is allenyl alcohol and the yields are 52∼84%.
A new variant of Knorr's pyrrole synthesis
Authors: Zhang Yan , Jiang Yun‐Zhen , Liang Xiao‐Tian
Published: September 2010

The reaction between ethyl 3‐bromopyruvate and p‐substituted anilines was found to involve the unexpected participation of acetone (solvent) forming N‐aryl‐5‐methyl‐pyrrole‐3‐carboxylates. The influence of p‐substituents of aniline and the feasibility with other ketones were studied. N‐aryl‐indole‐3‐carboxylate (17) was synthesized successfully with this method. The unique character of p‐methoxy‐aniline in this reaction was discussed.
Proton transfer across conducting polypyrrole membrane separated by two electrolyte solutions
Authors: Wang Han‐Ming , Yu Ze‐Mu , Wang Er‐Kang
Published: September 2010

Electrochemical behavior of the transfer of H+ across polypyrrole membrane (PPM) was studied. The transfer process was quasi‐reversible and mainly diffusion‐controlled. PPM electropolymerized in water solution has better reversibility than that in CH3CN solution for the transfer of H
+. The transfer process of H+ across the two kinds of PPM indicated that the PPM electrochemically polymerized was of asymmetry.
Synthesis of the optically pure 5,5″‐dihydroxy‐7,7″‐dimethoxy‐8,8″‐biflavone and its derivatives
Authors: Zhang Fang‐Jie , Lin Guo‐Qiang
Published: September 2010

( ± )‐5,5″‐Dihydroxy‐7,7″‐dimethoxy‐8,8″‐biflavone (( ± )‐l) was resolved into its optically pare forms via the formation and recrystallization of its (2R)‐ and (2S)‐1‐(4‐toluenesulfonyl)prolylate, and the methylated derivatives of (+)‐ and (‐)‐1 were also prepared. The absolute configurations of all these 8,8″‐biflavones have been confirmed by their CD spectra.
Catalytic oxidation of cyclohexene to cyclohexanone by a triple system in acidic aqueous acetonitrile medium
Authors: Li Hua‐Ming , Ye Xing‐Kai , Yang Xiang‐Guang , Wu Yue
Published: September 2010

The catalytic oxidation of cyclohexene to cyclohexanone using Pd(OAc)2/HQ/FePc wan investigated in an acidic aqueous solution of acetonitrile. The role of each component of this system in the oxidation of cyclohexene was explored by means of UV‐VIS, IR., XPS spectroscopy and cyclic voltammetry, respectively. Based on the experimental results, the mechanism of the oxidation of cyclohexene catalysed by Pd(OAc)2/HQ/FePc was elucidated.
Chiral separation of triazole pesticide enantiomers by high performance liquid chromatography
Authors: Yang Guo‐Sheng , Gao Ru‐Yu , Wang Qin‐Sun , Shen Han‐Xi
Published: September 2010

Four triazole enantiomers of diclobutrazol (erythro form) (1), paclobutrazol (erythro form) (2), diniconazole (3) and uniconazole (4) have been separated by high performance liquid chromatography (HPLC) on chiral stationary phase (CSP) OA‐4700. Chromatographic data and a chiral recongnition model are presented for the separation of these pesticide enantiomers. The influence of column temperature and composition of mobile phase have been described.
Bright red electroluminescent devices based on a soluble lanthanide complex Eu(DBM)3(phen)
Authors: Dong‐Ge Ma , Dai‐Ke Wang , Zhi‐Yong Hong , Xiao‐Jiang Zhao , Xia‐Bin Jing , Fo‐Song Wang , Bin Li , Hong‐Jie Zhang , Shu‐Bin Wang
Published: September 2010

Electroluminescent devices with PVK film doped with Eu(DBM)3(phen) and PBD were fabricated. The device structure of glass substrate/indium‐tin‐oxide/PPV/PVK:Eu(DBM)3(phen):PBD/Alq3/Al was employed. The emissive layer was formed by spin‐casting method. A sharply red electroluminescence with a maximum luminance of 114.4 cd/m2 was achieved at 42 V.
Intermolecular interaction between squarylium cyanine and porphyrin
Authors: Wei Zhao , Yuan‐Jun Hou , Xue‐Song Wang , Bao‐Wen Zhang , Yi Cao
Published: September 2010

In this paper, the interaction between squarylium cyanine and porphyrin in chloroform is investigated by absorption and fluorescence spectroscopy. Emphasis has been put on the mechanism of intermolecular energy transfer. The overlap integral J between the absorption spectrum of squarylium cyanine and the fluorescence spectrum of porphyrin was calculated, which reveals that the singlet‐singlet energy transfer may occur &om porphyrin to squarylium cyanine in solution. In comparison of the observed rate constant [k11q=6.1×1013 (mol/L)−1·s−l] for fluorescence quenching of porphyrin by squarylium cyanine with the diffusion rate constant in chloroform [kdif=1.1×1010 (mol/L)−1·s−1] and the rate of energy transfer [ket≤6.7×104 (mol/L)−1·s−1 in the experimentally dilute solutions] estimated from Forster formula, the possibility of energy transfer by electron exchange or/and coulombic mechanism could be excluded. So it has been definitely convinced that the intermolecular energy transfer between them is performed through long‐distance radiative mechanism which is in good agreement with the results in experimentally dilute concentration (<10−4 mol/L). Meanwhile, the fluorescence of squarylium cyanine can also be quenched by porphyrin, which suggests that photoinduced charge transfer with other process may occur. In the contrast, the results can be partly contributed to understand the reason why the energy transfer efficiencies of porphyrin ø11/et are always lower than its fluorescence quenching efficiencies øIq.
Synthesis and crystal structure of a Ni(II) complex with 1,7‐diaminoethyl‐4,10‐dimethyl‐1,4,7,10‐tetraazacyclododecane
Authors: Yong Liu , Guo‐Ping Xue , Cheng‐Tai Wu , Bao‐Sheng Luo
Published: September 2010

The crystal structure of a Ni(II) complex with 1,7‐diaminoethyl‐4,10‐dimethyl,4,7,10‐tetraazacyclododecane has been determined by X‐ray diffraction method. Crystal data for NiC14H36Br2N6O: monoclinic, space group P21/n, a=0.8848(3), b=1.4656(3), c=1.5828(3) nm, β=90.47(3)°, V=2.0525 nm3, Z=4. The two pendant primary amino groups are located in cis positions in the complex, their nitrogen atoms and the four nitrogen donors of the fold tetraaza‐macrocycle coordinate Ni(II) ion, forming a distorted octahedral geometry.
A facile convergent route to dendritic polyols
Authors: Ling‐Ling Weng , Ying‐Chun Chen , Hu Zheng
Published: September 2010

The synthesis of monodisperse dendrimers triggers a great challenge to the synthetic chemistry. Here, we reported a facile convergent approach to the synthesis of the first generation, six‐directional ether‐bond polyols with better controlled structures and ease of purification.
Design and synthesis of some new C2‐symmetric chiral disulfonamides from aminoacids and the application in diethyl zinc addition to benzaldehyde
Authors: Jian‐Qiang Wang , Min Zhong , Guo‐Qiang Lin
Published: September 2010

Nine C2‐symmetric chiral disulfonamides were designed and synthesized from L‐valine, L‐phenylalanine and L‐leucine respectively via one‐pot ring opening of aziridines. The application of these disulfonamides as catalyst in the addition of diethyl zinc to benzaldehyde in three reagent systems: Ligand‐Ti(OiPr)r‐Et2Zn; Ligand‐Ti(O'Pr)d‐HzO‐Et2Zn; Ligand‐Et2Zn was also described.
Photoluminescence quenching of quantum‐confined cadmium sulfide clusters by norbornadiene derivatives
Authors: Pu‐Hui Xie , Xue‐Song Wang , Bao‐Wen Zhang , Yi Cao
Published: September 2010

Influence of norbornadiene and its derivatives on the photoluminescence (PL) of quantum‐confined cadmium sulfide clusters (Q‐CdS) prepared in reverse micelles wm investigated. It was found that norbornadiene‐2,3‐dicarboxylic acid (3) and its monopotassium salt (4) quenched PL intensity by 77% and 62%, respectively, whereas its dipotassium salt (a), norbornadiene (1) and norbornadiene‐2,3‐dimethylcarboxylate (2) had no effect on PL intensity. The formation constants for adducts formed between defect sites at the surface of Q‐CdS clusters and 3 or 4 were also determined. PL quenching effect was attributed to the presence of ionizable proton which is considered to be able to trap photogenerated electrons and remove them from possible decay process. Measurements of the PL decay by single photon counting technique also supported these steady‐state observations.
Synthesis and reactivity of 3‐(trichlorogermyl)propanoic acid and 3‐(triphenylgermyl) propanoic acid
Authors: Qiang Zeng , Xian‐Shun Zeng , Qing‐Min Wang , Tao Cui , Zhong‐Biao Zhang
Published: September 2010

3‐(Trichlorogermyl)propanoic acid (1a) reacts with phenylmagnesium bromide in molar ratio 1:4 to give 3‐(triphenylgermyl)propanoic acid (2a). In the compounds 1a and 2a the β‐carboxylic functional group shows some unusual properties when they react with excess of phenylmagnesium bromide. The compound 1a reacts with phenylmagnesium bromide in molar ratio 1:5 to give phenyl 2‐(triphenylgermyl)ethylketone (3a) and in molar ratio 1:6 to give 1,1‐diphenyl‐3–(triphenylgermyl)propanol (4a). The compound 2a reacts with phenylmagnesium bromide in molar ratio 1:2 to give 3a and in molar ratio 1:3 to give 4a also. Dehydration of the compound 4a with dilute hydrochloric acid seems especially easy. Moreover, the compound la reacted with phenylmagnesium bromide in molar ratio 1:6, then the mixture was treated with dilute hydrochloric acid to give 1,1‐diphenyl‐3 (triphenylgermyl)‐1‐propene (5a) in one pot reaction. Alkyl Ge–C bond in the compound 5a can be cleaved selectively by lithium aluminium hydride (LiAlH4) in good yield.
Energy relationship and the polarization of C60 cage in the endohedral complexes (X@C60)
Authors: Zhi‐Jin Xu , Chuan‐Bao Zhu , Ji‐Min Yan
Published: September 2010

In this paper, we carry out the calculation on the system (X@C60)(X=Li, Na, K, Rb, Cs; F, C1, Br, I), where the position of X changes along 5 typical symmetry directions. For the calculation of quantum chemistry we use EHMO/ASED method, for the calculation of molecular mechanics we uee Buckingham potential (exp‐6‐1) function, and for the calculation of thermo‐chemical cycle we use individually isolating the processes such as the structure variation, charge transfer and charge distribution, and their interactions etc. The calculation results show that (1) In the region of radius τ≈0.2 nm of the C60 cage, the potential field is nearly spherical; (2) Except for Li and Na, the systems are the most stable with minimum energies at the center of C60 cage. For Li and Na, the systems are the most stable with minimum energies at τ≈0.16 run and τ≈0.13 nm, respectively. In view of the interactive region of chemical bonds, the interactions between X and the C60 cage do not belong to the classical chemical bonds; (3) The non‐bonding interaction between the X and C60 cage are not purely electro‐static, in which the electro‐static interactions only occupy ∼90% at mat on an average. The repulsion owing to the overlap of the electron cloud and the attraction owing to the dispersion can not be neglected. These two interactions determine the variations of size and trend of the system energies with r; (4) The polarization due to the position of X deviating from the center of C60 cage plays an important role at the moat stable positions of Li and Na.
Detection of complement C4 with a piezoelectric immunosensor
Authors: Ji‐Ming Hu , Ren‐Jun Pei , Yi Hu , Yun‐E Zeng
Published: September 2010

A piezoelectric immunosensor has been developed for the detection of complement C4. Anti‐C4 antibody was immobilized onto the gold electrodes of a 9 MHz AT‐cut piezoelectric crystal. The coated crystal with the physical adsorption method to immobilize antibody showed the better results than the polyethyleneimine adhesion, glutaraldehyde cross‐linking method with respect to sensitivity and reproducibility. The antibody‐bound crystal with the physical adsorption method was successfully used for the detection of human complement C4 in the concentration range of 0.1—10 μg/mL for 40 min incubation time. The immunosensor system had good selectivity, and other materials in human Serum did not interfere the detection remarkably. The crystal could be regenerated nearly 15 times when the bound materials on the crystal surface were eluted by strong acid and strong alkali solutions and subsequently cleaned in a ultrasonic cleaner.
Synthesis of homochiral spiro [4.4]nonane‐l,6‐diols
Authors: Yao‐Zhong Jiang , Minga Yan , Jian Sun , Wen‐Hao Hu , Zhi Li , Ai‐Qiao Mi , Albert S. C. Chan
Published: September 2010

Homochiral cis, cis‐; cis,trans and trans,trans‐spiro[4,4]‐nonane‐1,6‐diols were prepared via diastereoselective reduction of enantiomerically pure spiro[4.4]nonane‐l,6‐dione (1) with the corresponding reducing agents: lithium n‐butyldiisobutylaluminium hydride for cis,cis‐diol (2) with 88% yield; BH3·THF for cis, trans‐diol (8) with 91% yield; LiAlH4 for trans,trans‐diol (4) with 15% yield.
Synthesis and mesomorphic properties of novel tetrafluorinated biphenyl acetylene liquid crystals with a blue phase
Authors: Xi‐Min Chen , Hui‐Yong Yin , Yue‐Lian Xu , Jian‐Xun Wen
Published: September 2010

Five novel tetrafluorinated biphenyl acetylene molecules containing two chiral centres in the side chain were synthesized. The mesomorphic behaviour of these compounds was characterized by differential scanning calorimetry (DSC) and optical polarizing microscopy. All these compounds exhibit cholesteric and blue phases.
Catalytic asymmetric borane reduction of prochiral ketones using chiral camphor‐derived mercapto‐alcohols
Authors: Yong‐Gui Zhou , Xue‐Long Hou , Li‐Xin Dai
Published: September 2010

Easily available D‐(+)‐camphor‐derived chiral mercapto‐alcohols 2 and 3 were employed for catalytic asymmetric borane reduction of aromatic ketones. Moderate enantioselectivities with e.e. 20.2–72.1% were obtained with 10 mol% catalyst. Opposite asymmetric induction was achieved' when mercapto‐alcohols 2 and 3 were used.
Isoform‐selective modulators for metabotropic glutamate receptors and protein kinase C: Synthesis and biological evaluation
Authors: Da‐Wei Ma
Published: September 2010

The synthetic studies for some known modulators of metabotropic glutamate receptors (mGluRs) such as (S)‐αM4CPG, (1S,3R)‐ACPD, L‐CCG‐I are described. Based on the structure of αM4CPG several new conformationally constrained analogues are design ed and synthesized. Among them APICA is a selective antagonist for group II mGluRs. Also, a new benzolactam‐V8 analogue is found to have better isoform‐selectivity for protein kine C family. Three different protocols for synthesizing benzolactam‐VS analogues are developed to meet the requirement for delivering more analogues to test.
Microviscosity in modified Nafion membranes measured by fluorescence probes
Authors: Jing‐Qu Guan , Chen‐Ho Tung
Published: September 2010

Sodium or quaternary ammonium modified Nafion membranes in forms of Nafion‐Na+, Nafion‐NMe+4:, Nafion‐NEt+4 and Nafion‐NBu+4: have bean prepared by neutralizing Nafion‐H+ membrane with NaOH or tetraalkylammonium hydroxide aqueous solution. Intramolecular excimer formation and fluorescence polarisation methods using 1,3‐di(1‐pyrenyl)propane and acridine orange‐as probes respectively have been employed for measurements of the microviscosity within those modified Nafion membranes. Results show that the probes are located in the fluorocarbon/water interface in the cluster of the membranes and the microviscosities around the probe molecules an in the range of ca. 120–1200 cp and increase in the order of Nafion‐Na+ <Nafion‐NMe+4<Nafion‐NEt+4<Nafion‐NBu+4. Furthermore, the microviscosity values of these membranes in dry form an higher than those in wet form.
Synthesis and characterization of a one‐dimensional polymeric copper (II)‐tetrathioporphyrazine
Authors: Zheng‐He Peng , Tian‐You Peng , Zi‐Bin Qin
Published: September 2010

The title polymer PCuS4P5 was synthesied by reaction of 2,3‐dicyano‐5,6‐dihydro‐1,4‐dithiin, pyromellitic dianhydride and urea with cuprous salt in optimized gentle method. The structure and properties of the PCuS4P5 were characterized by elemental analysis, X‐ray powder diffraction, IR, UV‐Vis, fluorescence and EPR spectra and variable‐temperature magnetic susceptibility. The polymer is black sublimable crystallite and the degree of polymerisation has been found to be n>4. The PCuS4P5 in H2SO4 exhibits intensive absorption bands at 236, 342, 656 and 767 nm and intensive fluorescence band at 410 nm or 464 nm under the excitation of the ultraviolet light of a determined wavelength at room temperature. It has been found that the polymer exhibits a weaker antiferromagnetic interaction (J=−2.1 cm−l, μaff=1.68 B.M.) with an apparent spin S<1/2 in the ground state and its conductivity σ298K is 1.01×10−5 S·cm−1 at 13.73 MPa.
Intramolecular stacking interaction in mixed‐ligand complexes containing ATP4− and aromatic N‐heterocyclic ligands
Authors: Xue‐Yi Le , Fu‐Hai Wu , Xiao‐Feng He , Fen‐Yun Song , Liang‐Nian Ji
Published: September 2010

The stability constants of the binary ML2+ and ternary M(ATP)L2− complexes, where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn2+ or Cd2+, have been determined by potentiometric pH titration in aqueous solution at I=0.1 mol/L (NaClO4), T=25°C. The stability of the ternary complexes characterized by ΔlogKM=logKM(ATP)LM(ATP)L‐ logKMML corresponding to the equilibrium M(ATP)2− + ML2+ = M(ATP)L2− + M2+ in higher than what would be expected on statistical grounds. The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP4–. 1H NMR studies of Zn2+/ATP4−/L confirm the presence of stacking in the ternary complexes. It is concluded that the strength of the intramolecular stacking interaction ia dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge. Possible implications an discussed briefly.
A new synthesis of 1,6‐anhydrohexopyranoses
Authors: Chuan Li , Biao Yu , Guang‐Tao Zhang , Yong‐Zheng Hui
Published: September 2010

A new method for the preparation of l,6‐anhydrohexopyranoses was developed, which mainly involved a “one pot” condensation of 1,6‐hydroxyls of the corresponding hexopyranoses under N, N'‐sulfuryldiimidazole and sodium hydride.
Synthesis and properties of the copper(II) complexes with stable radical
Authors: Bai‐Wang Sun , Su‐Qi Li , Dai‐Zheng Liao , Zong‐Hui Jiang , Ai‐Jian Liu , Shi‐Ping Yan , Geng‐Lin Wang
Published: September 2010

Four novel copper(II) complexes have been synthesized, namely Cu(hfac)2NITPhNO2 (1), Cu(hfac)2NITPhCH3 (2), Cu(pfpr)2NITPhNO2, (3) and Cu(pfpr)2NITPhCH3 (4), where hfac=hexafluoro‐acetylacetonate, pfpr=pentafluoropropionate, NITR=2‐R‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide. (R=4‐nitrophenyl, 4‐methylphenyl). These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductance. The temperature‐dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4–300 K range, giving the exchange integral J=10.56 cm−l for complex 1 and J=−30.9 cm−l for complex 3.
27‐Nor‐triterpenoid saponins from Adina rubella
Authors: Gao‐Jun Fan , Zhi‐Sheng He
Published: September 2010

Three new 27‐nor‐triterpenoid saponins named rubenorside A (l), rubenorside B (2) and rubenorside C (9) were isolated from the roots of Adina rubella. Their structures were characterized as pyrocincholic acid 3β‐O‐α‐L‐rhamnopyranosyl(28→ 1)‐β‐D‐glucopyranosyl ester (1), pyrocincholic acid 3β‐O‐β‐D‐glucopyranosyl(1→2)‐β‐D‐fucopyranosyl(28→1)‐β‐D‐glucopyranosyl(1→6)‐β‐D‐glucopyranosyl ester (2) and pyrocincholic acid 3β‐O‐β‐D‐glucopyranosyl(1→2)‐β‐D‐glucopyranosyl (28→ 1)‐β‐D‐glucopyranosyl( 1→6)‐β‐D‐glucopyranosyl ester (S) by spectral methods, especially 2D NMR experiments.
Initiating system Me3SiCl/AlCl3 for cationic polymerization of 1,3‐pentadiene in toluene
Authors: Jian‐Guo Deng , Yu‐Xing Peng
Published: September 2010

Cationic polymerization of 1,3‐pentadiene (PD) initiated by trimethylsilyl chloride/aluminium chloride (TMSCI/AlCl3) was carried out in toluene at 30°C. The polymer yield was increased by the addition of TMSCl. However, introduction of TMSCl gave rise to a drop of the polymer molecular weight. Kinetic results demonstrated that the polymerization initiated by TMSCl/AlCl3 was 2.8 times faster than that induced by AlCls alone. Various ethers and ketones were used to mediate the initiating system TMSCI/AICl3. The polymer yield and molecular weight of the polymer were decreased in the presence of ether. Ketones and ethers had different effects on the polymerization, and the polymer yield and molecular weight were lower than those initiated by AlCls alone or TMSCl/AlCl3. Structural evidence revealed that the polymerization was indeed initiated by AlCl3 and HCl resulting from hydrolysis of TMSCl by adventitious water.
A total synthesis of (+)‐preussin and its 5‐epimer
Authors: Han‐Qing Dong , Guo‐Qiang Lin
Published: September 2010

(+)‐Preussin (1) and its 5‐epimer were synthesized from the divinylcarbinol (3) with Sharpless asymmetric epoxidation of 3 and the oxidative cyclization of 9 with PDC as the key steps.