bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorometric Investigation of the Acid‐Base and Complexation Behaviour of Tetracycline and Oxytetracycline
Authors: Li Hong‐Xia , Zhang Jun‐Jie , He Xi‐Wen , Li Guo‐Jiang
Published: September 2010

The widely used antibiotics tetracyclines have been effectively used for ailing heart attack, ulcer cure and gene therapy. The actual mechanism of their activity has been proposed to link with the complexes with many metal ions. However, the sites at which complex formation takes place are not well established. In the present work, the deprotonation sequence of tetracycline (TC) and oxytetracycline (OTC), and their specific group used to bind europium ion were investigated by examining the character of fluorescence of TC and OTC as well as that of their complexes. It was concluded that the site of complexation is coordinated with the deprotonation sequence changing with the acidity/basicity of the solution. And it was inferred that five hydrogens in TC and OTC could be dissociated. The deprotonation sequence is as follows: C(3) hydroxy, C(10) phenol, C(4) dimethylamine, C(12) hydroxy and C(12a) hydroxy. The corresponding complexation site changed with pH increase in solution as follows: C(2) acylamino and C(3) hydroxy moiety, C(10)‐C(11) ketophenol moiety, C(4) dimethylamine and C(3) hydroxy moiety, C(11)‐C(12) β‐diketone moiety, C(12) hydroxy and C(12a) hydroxy moiety, and C(12) hydroxy and C(1) ketone moiety respectively.
Synthesis, Reactivity and Crystal Structure of β‐Diketiminate Ytterbium Chlorides
Authors: Luo Yun‐Jie , Yao Ying‐Ming , Zhang Yong , Shen Qi , Yu Kai‐Bei
Published: September 2010

Reaction of anhydrous YbCI3 with 1 equiv. of LLi [L=p‐CIPhNC(Me)CH(Me)N(C6H3‐‐2,6‐i‐Pr2)] in THF at room temperature gave the diketiminate lanthanide dichloride LYbCl2(THF)2 (1) in good isolated yield. Similarly reaction of anhydrous YbCI3 with 1 equiv. of LLi, then with I equiv. of t‐BuCpNa in THF yielded the expected mixed‐ligand β‐diketiminate ytterbium chloride (t‐BuCp)YbL(μ‐CI)2 Li(THF)I (2). Both 1 and 2 were well characterized by elemental analysis, IR spectra, 1H NMR spectra, and X‐ray diffraction analysis.
Methylation of 5‐Amino‐3‐methylthio‐1 H‐pyrazole Derivatives and Two Related Crystal Structures
Authors: Ren Xue‐Ling , Wu Chao , Hu Fang‐Zhong , Zou Xiao‐Mao , Yang Hua‐Zheng
Published: September 2010

5‐Amino‐3‐methylthio‐1H‐pyrazoles are very important building blocks from which a wide variety of pyrazole derivatives can be prepared. When substituted 5‐amino‐3‐methylthio‐1H‐pyrazole was treated with CH3I, the methylation occurres at endocyclic two nitrogens at the same time. The ratio of isomers in products was depended upon the nature of 4‐position substituent in the pyrazole ring. The products were characterized by X‐ray diffraction analysis, and the ratios of isomer were explained by means of the results of ab inito calculation.
Glaser Coupling Reaction without Organic Solvents and Bases under Near‐critical Water Conditions
Authors: Li Pin‐Hua , Yan Jin‐Can , Wang Min , Wang Lei
Published: September 2010

A Glaser coupling reaction of terminal alkynes in the presence of cupric chloride without organic solvents and bases under near‐critical water has been developed.
Synthesis, Crystal Structure and Properties of a New One‐Dimensional 3d‐4f Compound
Authors: Qi‐Hua Zhao , Wang Qing‐Hua , Fang Rui‐Bin , Chen Zhi‐Da
Published: September 2010

A new heterometallic complex K2[{Eu(H2O)4}2{Fe11(bipy)(CN)4}4] 9H2O CH3OH [bipy=2,2′‐bipyridine] was synthesized. The compound has been characterized by X‐ray structure analysis, elemental analyses, IR spectrum, TGA thermogram and magnetic susceptibility. The complex consists of novel one‐dimensional ladder structure. The crystal belongs to monoclinic system with a space group P21/c. a =1.3946(4) nm, b=2.0450(6) nm. c=2.9722(8) nm. β= 99.W(5), V=8.372(4) nm3, Z=4. Dc= 1.562 g cm−3.
Molecularly Imprinted Polymer with Calix[4]arene Derivative for the Recognition of Acetanilide
Authors: Lu Chun‐Yang , He Hai‐Cheng , He Xi‐Wen , Zeng Xian‐Shunb
Published: September 2010

Two molecularly imprinted polymers binding to analgesic acetanilide were prepared using either dual functional monomers of calix[4]arene derivative and acrylamide or single monomer acrylamide, respectively. The polymers wen ground, sieved and investigated by equilibrium binding experiment to evaluate their recognition properties for the template and other substrates. Scatchard analysis showed that homogeneous recognition sites were formed in the imprinted polymer matrix. Our results demonstrated that the polymer using two functional monomers exhibited better selectivity for the template. This study may open new frontiers for the development and application of imprinted polymers, such as drug separation and purification.
Synthesis of Monodisperse Poly(glycidylmethacrylate‐co‐ethylene dimethacrylate) Beads and Their Application in Separation of Biopolymers
Authors: Gong Bo‐Lin , Ke Cong‐Yu , Geng Xin‐Du
Published: September 2010

The monodisperse poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) beads with macroporous in the range of 8.0–12.0 μn were prepared by a single‐step swelling and polymerization method. The seed particles prepared by dispersion polymerization exhibited good absorption of the monomer phase. The pore size distribution of the beads was evaluated by gel permeation chromatography and mercury instruction method. By using this media, a weak cation exchange (WCX) stationary phase for HPLC was synthesized by a new chemical modification method. The prepared resin has advantages of biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery and good resolution for proteins. The measured bioactivity recovery for lysozyme was (96 5)%. The dynamic protein loading capacity of the synthesized WCX packing was 21.3 mg/g. Five proteins were completely separated in 8.0 min using the synthesized WCX stationary phase. The experimental results show that the obtained WCX resin has very weak hydrophobicity. The WCX resin was also used for the rapid separation and purification of lysozyme from egg white in 8 min with only one step . The purity and specific bioactivity of the purified lysozyme was found more than 92.0% and 70184 U/mg, respectively.
Synthesis and Characterization of Donor‐Acceptor‐Donor Triads Containing Tetrathiafulvalene and Naphthalene Diimide Units: Towards Regulation of the Intermolecular Charge‐Transfer Interaction by Varying the Attached Side Groups
Authors: Guo Xue‐Feng , De‐Qing Zhang , Fan Qing‐Hua , Zhu Dao‐Ben
Published: September 2010

A series of donor‐acceptor‐donor triads 1–6 consisting of tetrathiafulvalene and naphthalene diimide units were synthesized and characterized. UV/Vis spectroscopic and cyclic voltammetric studies indicate that these triads show negligible intramolecular charge transfer interaction in the ground state. In contrast to that of the reference compound 36, their fluorescence intensities were reduced in the following sequences: 345612, which is probably due to photoinduced electron transfer in triads 1–6. Two solid forms (yellow and pen) of triads 1–5 were obtained, while only green form for triad 6 was obtained under the same conditions. Studies of the yellow and green forms with UV. XRD and DSC were performed. It was suggested that varying the attached side groups may regulate intermolecular charge transfer interactions in the solid state.
Preparation and Characterization of TiO2‐pillared Layered HNb3O8
Authors: Guo Xian‐Ji , Hou Wen‐Hua , Kong Yan , Ding Wei‐Ping , Fan Yi‐Ning , Yao Tian‐Yang , Yan Qi‐Jie , Chen Yi
Published: September 2010

Oligomeric titanium(IV) cation ([Ti(OH)x(H2O)y]&z−;)‐intercalated niobate was prepared through a stepwise ion‐exchange mute, in which n‐decylamine was employed as a preswelling agent and titanium isopropoxide as titanium source. Titania‐pillared layered niobic acid was then obtained by calcining oligomeric titanium(IV) cation‐intercalated niobate at 450 °C in air. Characterization of this pillared material indicated that the material had a porous layered structure with an interlayer distance of 1.38 nm and a BET (Brunauer‐Emmett‐Teller) surface area of 34 m2·g−1. The layered structure was still retained after the pillared material was heated at 550 T.
Synthesis and Crystal Structure of a Novel Zincophosphite Containing Two‐dimensional Inorganic‐organic Network
Authors: Yang Ya‐Li , Li Niu , Xiang Shou‐He
Published: September 2010

A novel 1,6‐hexamethylenediamine‐zincophosphite has been synthesized hydrothermally. Its single‐crystal structure refinement has shown the zincophosphite with the composition NH+3 (CH2)6 NH+3 [Zn(HPO3)2]2−, Mr= 343.55. It crystallizes in monoclinic, space group C2/c (No. 15). a=2.2391 nm, b=0.8695 nm, c=0.7919 nm, β= 101.062(6)°, V= 1.513 nm3, Dc= 1.508 kg/m3, Z=4, F(000)=712, μ=1.849 mm−1, R1 =0.0416. wR2=O.1023. This phase exhibits infinite inorganic chains of vertex‐linked ZnO4 and HPO3. Via the electrostatic attraction, 1.6‐hexamethylenediamine cations and inorganic chains construct a novel interesting two‐dimensional inorganic‐organic network.
Amperometric Biosensor for Hydrogen Peroxide Based on Electrodeposited Sub‐micrometer Gold Modified Glassy Carbon Electrode
Authors: Wang Shu‐Qing , Chen Jun , Lin Xiang‐Qin
Published: September 2010

A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub‐micrometer Au particles (sm‐Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition was optimized for obtaining uniformly distributed sub‐micrometer sized Au array on the electrode surface. The hydrogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue (MB) molecules on the surface of sm‐Au and covering a cross‐linked horseradish peroxidase (HRP) layer, labeled as HRP/MB/sm‐Au/GCE. The characteristics of this biosensor were evaluated with respect to applied potential and pH. The amperometric response of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10−6—1.11×10−2 mol/L. A detection limit (s/n=3) of 3.0×10−6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to −400 mV vs. SCE. The immobilized MB molecules shuttled electrons at α= 0.77 and an apparent electron transfer rate constant of k05 =0.053 s−1. Interference of ascorbic acid, dopamine and uric acid was investigated. This sensor has very good stability and reproducibility for long‐term use.
Factors Influencing Sulfinatodehalogenation Reactions of Perhalocarbons
Authors: Wu Kai , Chen Qing‐Yun
Published: September 2010

The study on the factors influencing sulfinatodehalogenation of perfluorohexyl chloride plus octene‐1 by using Na2S2O4/NaHCO3 discovered that among the various solvents tested (e.g. Me2SO, NMP, DMAc, CH3CN, CH3CN/H2O) at different temperatures, Me2SO was found to be the most suitable solvent and the conversion of the chloride was very dependent on the reaction temperature. When Me2SO was used in the reaction of perfluoroalkyl iodides. the reaction temperature could be decreased by 20 °C as compared with that carried out in CH3CN/H2O to reach the comparable yields.
Synthesis and Crystal Structure of 1D Coordination Polymer of N,N′‐Bis(3‐pyridylmethyl)‐1,4‐benzenedicarboxamide and Cobalt(II) Nitrate
Authors: Ge Chun‐Hua , Zhang Xiang‐Dong , Tong Jian , Zhang Peng , Guo Fang , Liu Qi‐Tao
Published: September 2010

A noval cobalt(II) coordination polymer, {[Co(bpmb)(H2O)2(C2H5OH)2]·(NO3)2}‐ (1). where bpmb=N,N′‐bis(3‐pyridylmethyl)‐1,4‐benzenedicarboxamide, was synthesized by self‐assembly of the two topic ligands with cobalt nitrate in ethanol solution, and characterized structurally by X‐ray crystallography analysis. The crystal data belong to triclinic, space group P1 with cell parameters a=0.8911(3) nm, b=0.9042(3) nm, c= 1.0068(3) nm, α= 73.083(5)°, β=81.069(5)°, γ=76.210(5)°, R1=0.0518, wR2=0.0947. The results of structure analysis indicate that each bpmb ligand coordinates two Co(II) atoms and each metal atom is in octahedral coordination geometry with four oxygen atoms of two ethanol and two water molecules, two nitrogen atoms from two different bpmb ligands in trans position forming an infinite 1D chain‐like structure. There BTC hydrogen bonding and π‐π stacking interaction among these chains, leading to supramolecular formation with 3D net structure.
Soluble polymer‐supported synthesis of pyrazoles via 1,3‐dipolar cycloaddition strategy
Authors: Lin Xu‐Feng , Wang Yan‐Guang , Ding Han‐Feng
Published: September 2010

Rapid parallel liquid‐phase synthesis of pyrazoles has first been developed. The 1,3‐dipolar cycloaddition between nitrilimines generated in situ and soluble polymer‐supported alkynyl or alkenyl dipolarophiles in parallel one‐pot fashion gave the corresponding PEG‐supported regioisomeric pyrazoles or regiospecific pyrazolines. The latter was assuredly oxidated by DDQ to PEG‐supported regiospecific pyrazoles. Cleavage from the support under mild conditions afforded pyrazoles in good yields and high purity.
Promotion of ionic liquid to dimethyl carbonate synthesis from methanol and carbon dioxide
Authors: Cai Qing‐Hai , Zhang Li , Shan Yong‐Kui , He Ming‐Yuan
Published: September 2010

Promotion of ionic liquid, 1‐ethyl‐3‐methylimidazolium bromide (emimBr), to the synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide in the presence of potassium carbonate and less amount of methyl iodide under mild conditions was investigated. The results showed that the high selectivity and raised yield of DMC was achieved due to the addition of emimBr in the reaction system. And effect of several reaction conditions such as Temperature, pressure and amount of emimBr was discussed.
Theoretical studies on electronic spectra and second‐order nonlinear optical properties of barbituric acid derivatives substituted with schiff base
Authors: Sun Gang , Qiu Yong‐Qing , Sun Hai‐Zhu , Su Zhong‐Min , Feng Jing‐Dong , Zhu Yu‐Lan
Published: September 2010

The structures of barbituric acid derivatives substituted with Schiff base were optimized using ab initio HF method at 6‐31G basis set. Based on the optimized structures, the electronic spectra were obtained by INDO/CI method. The second‐order nonlinear optical (NLO) coefficients βμ were calculated according to the sum‐over‐states (SOS) formula. In addition, the effect of conjugation on electronic specra and second‐order NLO coefficients was investigated. The influence of exchange between C and N atoms as well as the substituted effect on the barbituric acid was discussed. It was indicated that the exchange between C and N atoms on Schiff base is important for enhancing the NLO coefficient of the whole molecule with donor and acceptor (D‐A). Meanwhile significant changes in electron donation and acception were observed as substituents changes positions. Among the designed models, molecule lb has maximal βμ value of 124.65×10−‐30 esu. About molecule lb, barbituric acid is considered as an accepted electronic group and the position of N atom on Schiff base is close to it.
Intermolecular Phenolic Hydroxy Methylation Occurring between Chiral N,N′‐Bis(2‐hydroxyphenyl)‐2,2‐dimethyl‐1,3‐dioxolane‐4,5‐dicarbamide and Co‐crystallized Methanol under Electron Impact Ionization Conditions
Authors: Xu Jia‐Xi , Jiao Peng , He Zheng , Zhang Qi‐Han , Yan Chun‐Hua
Published: September 2010

An intermolecular phenolic hydroxy methylation occurring between chiral N,N′‐bis(2‐hydroxyphenyl)‐2,2‐dimethyl‐1,3‐dioxolane‐4,5dicarbamide and co‐crystallized methanol under electron impact ionization conditions was observed. The result was confirmed by X‐ray diffraction structural analysis of a co‐crystalline of (R,R)‐enantiomer and methanol.
Synthesis of Analogues of the Antitumor (1→6)‐Branched (1→3)‐Glucohexaose
Authors: Zeng You‐Lin , Zhang Jian‐Jun , Kong Fan‐Zuo
Published: September 2010

β‐D‐Glcp( 1→3)‐[β‐D‐Glcp‐( 1→6)‐/α‐D‐Manp‐( 1→3)‐β‐D‐Glcp( 1→3)‐[β‐D‐Glcp‐(1→6)‐]D‐Glcp (18) and β‐D‐Glcp( 1→3)‐[β‐D‐Glcp‐( 1→6)‐] α‐D‐Manp‐( 1→3)‐β‐D‐Glcp‐( 1 →3)‐[β‐D‐Glcp‐( 1→6)‐]β‐D‐Glcp‐D‐(1→3)‐Glcp‐1→OMe (29) were synthesized as the analogues of the immunomodulator β‐D‐Glcp‐(1→3)‐[β‐D‐Glcp‐(1→6)‐]α‐D‐Glcp‐(1→3)‐β‐D‐Glcp‐(1→3)‐(β‐D‐Glcp‐(1→6)‐]D‐Glcp through coupling of trisaccharide donors 9 with trisaccharide acceptor 16 and terrasaccharide acceptor 27 followed by deprotection. respectively.
Synthesis of Polymer‐bound Sensitizers and their Applications in the Preparation of Previtamin D3 from Tachysterol
Authors: You Chang‐Jiang , Xie Rong , Gao Yun‐Yan , Han Yong‐Bin , Yang Guo‐Qiang , Li Yi
Published: September 2010

Two kinds of polymer‐bound photosensitizers were synthesized, in which anthracene acts as sensitizer moiety, polystyrene (PS) and poly(methyl methylacrylate) (PMMA) serve as solid phase supports, respectively. The photoisomerization of tachysterol to previtamin D3 was carried out with these polymer‐bound photosensitizers in ethanol and toluene solutions. The experiment results demonstrate that these solid phase photosensitizers are efficient for the photoisomerization with good recycle property and can be simply separated from the reaction mixtures by filtration.
Calculation of two‐center nuclear attraction integrals over slater type orbitals in molecular coordinate system
Authors: Mamedov B. A.
Published: September 2010

A closed analytical relation is derived for the two‐center nuclear attraction integrals over Slater type orbitals (STOs) in terms of binomial coefficients. This formula can be used in highly accurate calculations of the nuclear attraction integrals. The relationships obtained are valid for arbitrary values of quantum numbers and screening constants of STOs and location of nuclei.
Ionic liquids as mobile phase additives for separation of nucleotides in high‐performance liquid chromatography
Authors: Zhang Wen‐Zhu , He Li‐Jun , Liu Xia , Jiang Sheng‐Xiang
Published: September 2010

Ionic liquids are a type of salts that are liquid at low temperature (<100 °C). Because of their some special properties, they have been widely used as new “green solvents” for many chemical reactions and liquid‐liquid extraction in the past several years. In this paper, a new method for the separation of nucleotides is developed and the essential feature of the method is that 1‐alkyl‐3‐methylimidazolium salts are used as mobile phase additives, resulting in a baseline separation of nucleotides without need of gradient elution and need of organic solvent addition as currently used in RP‐HPLC. This study shows the potential application of ionic liquids as mobile phase additives in reversed‐phase liquid chromatography.
Synthesis and conformation ofcis‐1,2‐disubstituted cyclododecene
Authors: Han Xiang‐Yu , Wang Ming‐An , Liang Xiao‐Mei , Wang Dao‐Quan
Published: September 2010

Eight 1,2‐disubstituted cyclododecenes were synthesized from α‐alkoxycarbonyl‐cyclododecanone and alkyl chloroformate. Their configuration and conformation determined by IR, NMR spectroscopy and X‐ray diffraction analysis showed that the carbon‐carbon double bond of all of the synthesized compounds hascis‐configuration. and the ring skeleton of their preferred conformation is [lene2333] in solid, and they may adopt two different [lene2333] conformations, which exist in a dynamic equilibrium in solution.
Mechanism and Kinetics for the Reaction of NCS and OH Radicals
Authors: Liu Peng‐Ju , Zhao Min , Chang Mng‐Fei , Zhao Yan‐Ling , Su Zhong‐Min , Wang Rong‐Shun
Published: September 2010

The mechanism and dynamical properties for the reaction of NCS and OH radicals have been investigated theoretically. The minimum energy paths (MEP) of the reaction were calculated using the density functional theory (DFT) at the B3LYP/6‐3 11 +G**level, and the energies along the MEP were further refined at the QCISD(T)/6‐311 +G** level. As a result, the reaction mechanism of the title reaction involves three channels, producing HCS+NO and HNC+SO products, respectively. Path I and path LI are competitive, with some advantages for path I in kinetics.As for path 111. it looks difficult to react for its high energy barrier. Moreover, the rate constant have been calculated over the temperature range of 800‐2500 K using canonical variational transition‐state theory (CVT). It was found that the rate constants for both path I and path II are negatively dependent on temperature, which is similar with the experimental results for reactions of NCS with NO and NO*, and the variational effect for the rate constant calculation plays an important role in whole temperature range.
Density functional study on the mechanism of collision reaction among protons, N2 and water vapor
Authors: Sun Hao , Pan Xiu‐Mei , Zhao Min , Liu Peng‐Jun , Su Zhong‐Min , Wang Rong‐Shun
Published: September 2010

The mechanism of collision reaction among protons, N2 and water vapor was theoretically studied using Density Functional Theory. The geometries of reactants, transition states, intermediates and products were optimized at the B3LYP/6‐311+G** level by the BERNY gradient analysis method. Transition states and intermediates have been identified by vibrational frequency analysis. The relationship among reactants, intermediates, transition states and products was affirmed by IRC calculation. The variations of energy and geometry along the IRC determined reaction paths were described. The possible reaction pathways were represented and the optimal one was decided from the viewpoint of energy.
On the correlation between the blue shift of hydrogen bonding and the proton donor‐proton acceptor distance
Authors: Wang Jin‐X , Feng Yong , Liu Lei , Li Xiao‐Song , Guo Qing‐Xiang
Published: September 2010

It is demonstrated that in all types of hydrogen bonds (XH···Y) there is a balance between the long‐range attractive orbital interactions and short‐range Pauli/nucleus repulsions. When the proton acceptor approaches the proton donor from distance, the hydrogen bonding energy becomes more negative at relatively large distance, goes through a minimum. and then starts to become less negative when the short‐range repulsive forces come into effect Meanwhile, the XH bond length increases at relatively large distances, goes through a maximum and starts to shorten when the short‐range repulsive forces come into effect. Whether the hydrogen bond is red or blue shifted is dictated by the energy minimum position. If at the energy minimum position the XH bond length is shorter than that for the free monomer, the hydrogen bond is blue shifted and vice versa. Further studies demonstrate that the recent report about the correlation of CH bond lengths with proton donor‐acceptor distance in F3CH···OH2and F3CH···Cl is not fully correct because the authors conducted an inappropriate comparison. Furthermore, it is shown for the first time that the Pauli/nucleus repulsion theory is applicable to the blue‐shifted hydrogen bonds in the XH···π complexes and the blue‐shifted lithium bonds in the XLi···Y complexes.
Chemical liquid phase deposition of thin aluminum oxide films
Authors: Sun Jie , Sun Ying‐Chun
Published: September 2010

Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system's pH value played an important role in this experiment. The growth rate is 12 nm/h with the deposition at [Al2(SO4)] =0.0837 mol·L−1, [NaHCO3] = 0.214 mol·L−1, 15 °C Post‐growth annealing not only densifies and purifies the films, but results in film crystallization as well. Excellent quality of Al2O3 films in this work is supported by electron dispersion spectroscopy. Fourier transform infrared spectrum, X‐ray diffraction spectrum and scanning electron microscopy photograph.
Synthesis, structure and catalytic activity comparison of tris‐ and tetracoordinated lanthanide amides
Authors: Xie Mei‐Hua , Liu Xin‐Yuan , Wang Shao‐Wu , Liu Li , Wu Yong‐Yong , Yang Gao‐Sheng , Zhou Shuang‐Liu , Sheng En‐Hong , Huang Zi‐Xiang
Published: September 2010

Tetracoordinated lanthanide amides [(Me3Si)2N]3Ln (μ‐CI)Li(THF)3 (Ln=La (1), Pr (2)) were synthesized by the reaction of anhydrous lanthanide(III) chlorides LnCl3 (Ln=La, Pr) with 3 equiv. of lithium bis(trimethyl‐silyl)amide (Me3Si)2NLi in THF, followed by recrystallization from toluene. Sublimation of 1 and 2 afforded the triscoordinate lanthanide amides [(Me3Si)2N]3Ln (Ln=La, Pr). The crystal structure of 2 was determined by X‐ray diffraction analysis. The catalytic activity studies show that the tetracoordinate amides can be used as single‐component MMA (methyl methacrylate) polymerization catalysts, while the triscoordinate amides showed poor activity on h4MA polymerization under the same conditions.
A novel reductive cyclization of o‐nitrobenzamides and ketones promoted by low‐valent titanium reagent
Authors: Shi Da‐Qing , Rong Liang‐Ce , Wang Ju‐Xian , Zhuang Qi‐Ya , Tu Shu‐Jianga
Published: September 2010

A short and facile synthesis of a series of 1, 2‐dihydroquiazolin‐4(3H)‐ones was accomplished in good yields via novel reductive cyclization of o‐nitrobenzamides with ketones promoted by TiCl4/Zn system. The structure was established on the basis of elemental analysis, IR, 'H NMR and confirmed by a single‐crystal X‐ray diffraction analysis. This method has the advantages of easily accessible starting materials, convenient manipulation and moderate to high yields.
A novel catalytic system—NdCl3 · HMPA/AI(i‐6u)3 for copolymerization of isoprene and styrene
Authors: Xu Xiao‐Ming , Ni Xu‐Feng , Shen Zhi‐Quan
Published: September 2010

Co polymerization of styrene (St) and isoprene (IP) was carried out with a catalyst system composed of anhydrous lanthanide chloride hexamethyl phosphor amide complex (LnC13‐HMPA) and aluminum organic compound (AOC). Among the catalysts examined, catalyst NdC13*HMPA/Al(i‐Bu)3 showed a high activity in the copolymerization under certain conditions giving copolymers (5%‐158 St content) with high cis‐1, 4 microstructure in IP Units (>95%). The effects of HMPA/Nd molar ratio, Al/Nd molar ratio, monomer/Nd molar ratio, St feed ratio, and the reaction time on copolymerization were examined with this catalytic system. The obtained copolymers were characterized by 1H and 13C NMR spectroscopies and gel‐permeation chromatography (GPC).
A novel non‐phosgene process for the synthesis of methyl N‐phenyl carbamate from methanol and phenylurea: Effect of solvent and catalyst
Authors: Wang Xin‐Kui , Yan Shi‐Run , Cao Yong , Fan Kang‐Nian , He He‐Yong , Kang Mao‐Qing , Peng Shao‐Yi
Published: September 2010

A novel environmentally benign process for the synthesis of methyl N‐phenyl carbamate (Mpc) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to Mpc increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n‐octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to Mpc while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.
Investigation on molecular non‐covalent interaction in the sodium dodecyl benzene sulfonate‐polychrome blue B‐protein replacement reaction
Authors: Gao Hong‐Wen , Wu Ji‐Rong , Shen Rong
Published: September 2010

The molecular noncovalent interaction often originates from the electrostatic attraction and accords with the Langmuir isothermal adsorption. The sodium dodecyl benzene sulfonate (SDBS)‐polychrome blue B (PCB>protein bovine serum albumin (BSA), ovalbumin (OVA) and myoglobin (MB)] ternary reaction has been investigated at pH 3.88. Protein to replace PCB from the PCB‐SDBS binding product was used to characterize the assembly of an invisible‐spectral compound, SDBS, on proteins by measuring the variation of FCB light‐absorption by tbe micro‐surface adsorption‐spectral correction (MSASC) technique. The effect of ionic strength and temperature on the aggregation was studied. Results showed that the aggregates SDBS92·BSA, SDBS58·VA and SDBS15·MB at 30 C and SDBS83·BSA. SDBS39·OVA and SDBS10·MB at 50 °C are formed.
Selective oxidation of propane over CsFePVAsMo heteropoly compound catalyst
Authors: Cai Tie‐Jun , Yu Chang‐Lin , Deng Qian , Peng Zhen‐Shan , Long Yun‐Fei , Lü Xiao‐Meng
Published: September 2010

Both the partially reduced and non‐reduced multi‐component heteropoly compound catalysts with Keggin structure were prepared and used for the selective oxidation of propane. The catalysts were characterized by IR, H2‐TPR, NH3,‐TPD, SEM and XRD. The addition of Cs increased the selectivity of acrylic acid and acetic acid. The selective oxidation performance was greatly improved with the addition of As. Among all of the tested catalysts, the catalytic performance of the Cs1.8Fe0.16HxPVAs0.4Mo11O40 (non‐reduced) was the best and the maximum yield of acrylic acid reached 16.42%.
Crystal structure, thermal analysis and theoretical calculation of a one‐dimensional chain complex [zn(dafo)2(H2O)2](NO3)2
Authors: Zhang Rong‐Lan , Zhao Jian‐She , Gao Xin , Shi Qi‐Zhen , He Shui‐Yang
Published: September 2010

A novel one‐dimensional chain complex [Zn(dafo)2(H2O)2](NO3)2 was obtained when we tried synthesizing a mixed ligand supramolecular compound of Zinc(II) with dafo and o‐phthalic acid. Its structure was determined by single‐crystal X‐ray diffraction analysis. The crystal belongs to triclinic system, P‐1 space group. The crystallographic data: a=0.6989(4) nm, b=0.8281(5) nm, c=1.0231(5) nm, α=94.934(5)°, β=91.366(7)°, γ=99.820(7)°, V=0.5809(5) nm3, Z= 1, F(000)=300, Mr=589.78, Dc=1.686 g/cm3, μ(Mo Kα)=1.130 mm−1, R1=0.0521, wR2=0.1096. The analysis of the crystal structure indicates that the compound has a one‐dimensional chain structure which is formed by hydrogen bonds. The constitutes of the title complex were proved by elemental analysis, IR spectra and thermal analysis. On the basis of the experimentation, the complex was calculated by DFT‐B3LW/LANL2DZ in Gaussian‐98w also.
Stereoselective synthesis of (E)‐α‐aryltellurenylvinylstannanes and their application in the synthesis of stereodefined trisubstituted alkenes
Authors: Cai Ming‐Zhong , Huang Jia‐Di , Zhang Rong‐Li
Published: September 2010

(E)‐α‐Aryltellurenylvinylstannanes have been synthesized stereoselectively via the hydrozirconation of alkynylstannanes, followed by the reactions with aryltellurenyl iodides. (E)‐α‐Aryltellurenylvinylstannanes can undergo sequential cross coupling reactions with both electrophiles and nucleophiles in the presence of transition metal complexes to form two carbon‐carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereoselectively.
Homocoupling of polyfluorovinylstannanes mediated by a novel combination of CuCl/2,2′‐dipyridyl. Stereospecific synthesis of polyfluorinated alka‐2,4‐dienes
Authors: Shen Yan‐Chang , Wang Guo‐Ping
Published: September 2010

A new homocoupling methodology mediated by a novel combination of CuCl‐2,2‐dipyridyl and its application to the synthesis of substituted polyfluorinated alka‐2,4‐dienes are described.
Synthesis and crystal structure of a New Diamine complex CuCl4(H2tn)
Authors: Zhang Gai , Zhang Rong‐Lan , Zhao Jian‐She , Gao Xin , Wang Shao‐Kang , He Shui‐Yang
Published: September 2010

In an attempt to synthesize a new pyrimidine complex of copper(II) in a solution reaction of CuBr2 with 2,2′‐bis(hexahydropyrimidine) and hydro‐chloric acid, we unexpectedly obtained a bright yellow chip‐like crystal of CuC4(H2tn) [H,tn=(H3NCH2CH2CH2NH3)2+]. Its structure was determined by single‐crystal X‐ray diffraction analysis. The crystal belongs to orthorhombic system, space group Pnma, with cell parameters: a=0.7216(2) nm, b= 1.8308(6) nm, c=0.7553(3) nm, V=0.9953(6) nm3, Z=4, F(000)=564, Mr=281.49, D,= 1.879 g/cm3. μ(Mo Ka)=3.204 m−1, R1=0.0248, wR2=0.0575. The analysis of the crystal structure indicates that the complex has a three‐dimensional network structure, which is formed by hydrogen bonds and electrostatic interaction.
Total synthesis of tetrahydroquinoline alkaloid (+)‐Angustureine
Authors: Lin Xian‐Feng , Li Yu , Ma Da‐Wei
Published: September 2010

(+ )‐(S)‐Angustureine was synthesized using a CuI‐catalyzed coupling reaction of iodobenzene with an enantiopure β‐amino ester as the key step. The overall yield is 36% in 7 linear steps.
Synthesis and characterization of ethylthioethylcyclopentadienyl organolanthanide complexes: CpLnCl (Ln=Gd, Dy), Cp2LnCpTh (Ln=Yb, Sm, Dy, Y) and CpThErCl2·2THF
Authors: Zhu Ming , Zhang Li‐Bei , Chen Ying‐Hua , Zhou Xi‐Geng , Cai Rui‐Fang , Weng Lin‐Hong
Published: September 2010

Six new ethylthioethylcyclopentadienyl containing organolanthanide complexes CpLnCl [Ln=Gd (1), Dy (2)] and Cp2LnCpTh [Cp=C5H5, Ln=Yb (3), Sm (4), Dy (5), Y (6)] were synthesized by the reaction of ethylthioethyl‐cyclopentadienyl (CpTh) sodium salt with LnCl3 or Cp2LnCl in THF. Complexes 1–6 were characterized by elemental analyses, infrared and mass spectroscopies. The molecular structures of complexes 1–3 were also determined by the X‐ray single crystal diffraction. The results show that the side‐chain sulfur atom on the ethylthioethylcyclopentadienyl ring can form intramolecular chelating coordination to the central lanthanide ion, improving the stability of organolanthanide complexes and reducing the number of coordinated THF molecules.
Synthesis of 5‐fluoroalkyl lsoxazolidines via 1,3‐dipolar cycloaddition of ethyl 2‐hydropolyfluoroalk‐2‐enoates with nitrones
Authors: Liu Jin‐Tao , Jin Qi‐Hui , Lü He‐Jun , Huang Wei‐Yuan
Published: September 2010

1,3‐Dipolar cycloaddition reactions of ethyl 2‐hydropolyfluoroalk‐2‐enoates (1) with some nitrones were described. The reaction of 3,4‐dihydroisoquinoline N‐oxide (2) with 1 took place readily in methylene chloride at room temperature to give the corresponding 5‐fluoroalkylisoxazolidines regioselectively as a mixture of two diastereoisomers (trans and cis) in high yields, while longer reaction time and higher temperature were needed in the case of non‐cyclic nitrones. Under similar conditions the reaction of quinoline N‐oxide (14) with 1 did not give the expected adducts and a ring‐opening product was obtained.
A simple and highly efficient preparation of structurally diverse aryl β‐diketoacids as hiv‐1 integrase inhibitors
Authors: Jiang Xiao‐Hua , Long Ya‐Qiu
Published: September 2010

In order to provide a facile and practical access to structurally diverse aryl β‐diketoacids, An improved and highly efficient oxalylation method was developed which employed commercially available and cheap reagents. The oxalylation of aryl methyl ketones, the key step to construct the pharmacophore of aryl β‐diketoacids. was considerably facilitated by a new combination of dimethyl oxalate as an oxalic source and sodium tert‐butoxide as a base. A wide variety of aryl β‐diketoacids bearing different functional groups can be prepared rapidly in high yields at room temperature with this method, which has significant advantages over the previously reported procedures in a wider application range, much less amount of reagents, pretty higher yields and quite shorter reaction time. The bis‐aryldiketoacids 3k and 31, readily prepared by this method, displayed interesting and promising inhibitory activities against HIV‐1 integrase and HN‐I replication in cells.
Synthesis and biological activity of tonghaosu analogs containing phenoxy‐phenyl moiety
Authors: Chen Li , Xu Han‐Hong , Yin Biao‐Lin , Xiao Chun , Hu Tai‐Shan , Wu Yu‐Lin
Published: September 2010

A new series of phenoxy‐phenyl moieties containing tonghaosu analogs with varied B‐ring 9 were synthesized and characterized by spectral studies. Their insect antifeedant activity against Pieris brassicae and insecticidal activity against Culex quinquefasciatus were investigated. Compound 9e exhibited excellent antifeeding activity.
Some attempts to employ the singlet oxygen generated from H2O2
Authors: Jin Hong‐Xia , Liu He‐Hua , Wu Yi‐Kang
Published: September 2010

Some attempts to employ the singlet oxygen generated from molybdate‐catalyzed decomposition of hydrogen peroxide are presented. Reduction of ascaridole with diimide is also described, along with the preliminary results of the cleavage study using Fe‐cysteinate as a simple model for FeS type redox species. There were strong indications that S‐alkylation occurred as observed in similar cleavage of the potent antimalarial qinghaosu.
Thermal decomposition behavior and non‐isothermal decomposition reaction of copper(II) salt of 4‐hydroxy‐3,5‐dinitropyridine oxide and its application in solid rocket propellant
Authors: Chen Pei , Zhao Feng‐Qi , Luo Yang , Hu Rong‐Zu , Gao Sheng‐Li , Zheng Yu‐Mei , Deng Min‐Zhi , Gao Yin
Published: September 2010

The thermal decomposition behavior and kinetic parameters of the exothermic decomposition reactions of the title compound in a temperature‐programmed mode have been investigated by means of DSC, TG‐DTG and lower rate Thermolysis/FTIR. The possible reaction mechanism was proposed. The critical temperature of thermal explosion was calculated. The influence of the title compound on the combustion characteristic of composite modified double base propellant containing RDX has been explored with the strand burner. The results show that the kinetic model function in differential form, apparent activation energy Ea and pre‐exponential factor A of the major exothermic decomposition reaction are 1‐a,207.98 kJ*mol−1 and 1015.64 s−1, respectively. The critical temperature of thermal explosion of the compound is 312.87 C. The kinetic equation of the major exothermic decomposition process of the title compound at 0.1 MPa could be expressed as: dα/dT=1016.42 (1–α)e‐2.502×104/T As an auxiliary catalyst, the title compound can help the main catalyst lead salt of 4‐hydroxy‐3,5dinitropyridine oxide to enhance the burning rate and reduce the pressure exponent of RDX‐CMDB propellant.
Thermal decomposition kinetics of triethylene glycol dinitrate
Authors: Chen Pei , Zhao Feng‐Qi , Luo Yang , Hu Rong‐Zu , Li Shang‐Wen , Gao Yin
Published: September 2010

The thermal behavior and kinetic parameters of the decomposition reaction of triethylene glycol dinitrate (TEGDN) in a temperature‐programmed mode at different pressures (0.1, 2, 4 and 6 MPa) have been investigated by means of DSC and TG‐DTG. The results show that the properties of the thermal decomposition of TEGDN are affected by the change of pressure, and the kinetic model function, the apparent activation energy Ea. and pre‐exponential factor A of this reaction are 2(1−α)[−ln(1−α)]1/2, 106.54 kJ·mol−1 and 109.17s−1 at 0.1 MPa, and 120.82 kJ·mol−1 and 1010.56 s−1 at 2 MPa, respectively. The critical temperature of thermal explosion of TEGDN obtained by the values Teo and Tpo of the onset temperature Te and the peak temperature Tp when the heating rate tends to zero are 191.05, 209.86 °C at 0.1 MPa, 207.59 and 221.65 °C at 2 MPa, respectively.
Kinetic study on the exothermic decomposition reaction of 2,4,6,8‐tetranitro‐2,4,6,8‐tetraazabicyclo[3,3,1]onan‐3,7‐dione
Authors: Hu Rong‐Zu , Song Ji‐Rong , Zhao Feng‐Qi , Wang Bo‐Zhou , Gao Sheng‐Li , Zhu Chun‐Hua , Chen Pei , Luo Yang , Ning Bin‐Ke , Chen San‐Ping , Shi Qi‐Zhen
Published: September 2010

The kinetic parameters of the exothermic decomposition reaction of the title compound in a temperature‐programmed mode have been studied by means of DSC. The empirical kinetic model function in differential form, apparent activation energy (Ea) and pre‐exponential factor (A) of this reaction are (1−α)0.222, 225.8 kJ·mol−1 and 1020.21 s−1, respectively. The critical temperature of thermal explosion of the compound is 224.9°C.
Investigation of the crystallization kinetics of Zn(Met)(AcO)2·H2O in mixed solution of water and acetone by microcalorimetry
Authors: Ren Yi‐Xia , Gao Sheng‐Li , Chen San‐Ping , Jiao Bao‐Juan , Hu Rong‐Zu , Shi Qi‐Zhen
Published: September 2010

The crystal growth process of Zn(Met)(AcO)2·H2O from the mixed solution of water and acetone has been investigated using a Calvet microcalorimeter. The heat produced and the rate of heat production during the crystal growth process at 298.15, 301.15, 304.15, 307.15 and 310.15 K have been measured. On the basis of experimental and calculated results, the thermodynamics parameters (the apparent activation enthalpy, the activation entropy, and the activation free energy), the rate constant and the kinetic parameters (the activation energy, the pre‐exponential factor) during the crystal growth process have been obtained. The results show that the crystal growth proceeds in accordance with the Burton‐Cabrera‐Frank dislocation theory.
Thermokinetic study on the complexation reaction of the first‐row transitional metal chlorides with histidine
Authors: Chen San‐Ping , Gao Sheng‐Li , Shi Qi‐Zhen
Published: September 2010

The enthalpy change of the complexation reactions of the first‐row transitional metal chlorides including CrCl3, MnCl2, FeCl2, CoCl2, NiCl2 and CuCl2 with L‐α‐histidine in water were determined by a microcalorimeter at 298.15‐323.15 K. The standard enthalpy of formation of Cr(His) (aq) and M(His) (aq) (M=Mn, Fe, Co, Ni and Cu) were calculated. Based on the thermodynamic and kinetic equations of the reactions, three thermodynamic parameters (the activation enthalpy, the activation entropy, the activation free energy), the rate constants, and three kinetic parameters (the apparent activation energy, the pre‐exponential constant and the reaction order) are obtained. The solid complexes of CrCl3, MnCl2, FeCl2, CoCl2, NiCl2 and CuCl2 with histidine were prepared and identified as Cr(His)2Cl3·H2O. Mn(His)2Cl2·4H2O. Fe(His)2Cl2·H2O, Co(His)2Cl2·H2O, Ni(His)2Cl2·H2O and CU(HiS)2Cl2·H2O by chemical and elemental analyses. The bonding characteristics of these complexes were characterized by R as well. The results showed that, with the atomic number increasing, three thermodynamic parameters, ΔG, ΔH and ΔS of the complexation reaction of these metal chlorides with L‐α‐histidine in water present an analogy regularity.
Synthesis and electrochemical characterization of gradient composite LiNi1−yCoyO2 used as cathode materials in lithium‐ion battery
Authors: Zhao Yu‐Juan , Xia Ding‐Guo , Liu Qing‐Guo
Published: September 2010

Gradient composites, LiNi1−yCoyO2, are synthesized from coated spherical Ni(OH)2 precursor. These composites could be applied as new cathode materials in lithium‐ion batteries because they have low cobalt content (y≤0.2) and exhibit excellent properties during high‐rate charge/discharge cycles. The initial discharge capacity of coated composite of LiNi0.95O2 is 186 mAh/g, and the decreasing rate of the capacity is 3.2% in 50 cycles at 1 C rate. It has been verified by TEM and EDX experiments that a core‐shell structure of the composite particles develops because of the cobalt enrichment near the surfaces, and the formation of the cobalt enrichment layer is sensitive to sintering tempera‐. High cobalt surface concentration may reduce the undesired reactions and stabilize the structure of the particles.
Aluminum ion removal from monoaluminum ovotransferrin by pyrophosphate
Authors: Li Ying‐Qi , Yang Bin‐Sheng
Published: September 2010

The rates at which aluminum was removed from the N‐ and C‐terminal monoaluminum ovotransferrins by pyrophosphate were evaluated by UV difference spectra in 0.01 mol/L Hepes, pH=7.4 and at 37 °C. Pesudo first‐order rate constants as a function of pyrophosphate concentration were measured. The results indicate that the pathways of aluminum removal are different. For the N‐terminal binding site, aluminum removal follows simple saturation kinetics, while the removal of aluminum from the C‐terminal binding site reverts to the combination of saturation and first‐order kinetics. The saturation component is consistent with a rate‐limiting conformational change in the protein as has been reported. We propose that the first‐order kinetics mechanism is attributed to a pre‐equilibrium process. The rate constants of saturation kinetics are accelerated from both terminals with the addition of 0.1 mol/L chloride to the monoaluminum ovotransferrin solutions, whereas the rates of the first‐order kinetics are decreased for the C‐terminal binding site. The effect of chloride ionic strength causes a continuing increase on kobs for the N‐ and C‐terminal binding sites. Moreover, the kinetics behavior of the N‐terminal is more easily affected by chloride than that of the C‐terminal. In the experiment presumably the N‐terminal site is apparently kinetically more labile than the C‐terminal site.
Electrochemical characteristics of Mg0.9Ti0.1‐xZrxNi (x=0.02, 0.04, 0.06) alloys
Authors: Yuan Hua‐Tang , Feng Yan , Qiao Lin‐Jun , Liu Qiang , Wang Yi‐Jing
Published: September 2010

Mg‐based hydrogen storage alloys Mg0.9Ti0.1‐xZrxNi (x=0.02, 0.04, 0.06) were successfully prepared by means of mechanical alloying (MA). The effects of Zr addition on the discharge capacity and the cycle performance of the Mg‐based electrodes were also studied. It was found that the discharge capacities were improved with addition of a small amount of Zr and the cycle performances of the alloy were stabilized with the addition of Ti. the effects of surface modification or coating on the properties of Mg0.9Ti0.1‐xZrxNi were also studied. The results indicated that coating with graphite improved both the discharge capacity and cycle life of the amorphous Mg0.9Ti0.1‐xZrxNi electrode.
Determination of ultratrace silver using surfactant as sensitizer by catalytic near field laser thermal lens spectrometry
Authors: Han Quan , Yan Hong‐Tao , Qian Zhen‐Jie
Published: September 2010

A new method for the determination of ultratrace silver(I) by near field laser thermal lens spectrometry has been developed. This method is based on the silver(I) catalyzed discoloring reaction of bromcresol green oxidized by sodium persulfate in the presence of α,α'‐bipyridine as an activator and TritonX‐100 as a sensitizer. The reaction mechanism was discussed. The linear range of the method is 0–1.6 ng·mL−1 and the detection limit is 2×10−2 ng·mL−1 for silver. The method has been applied to the determination of silver in lead powder and photographic paper with satisfactory results.
A facile synthesis of ethyl 2,4‐dimethoxy‐6‐perfluoroalkyl‐benzoates via acyclic precursors
Authors: Cao Wei‐Guo , Shi Zhi‐Jian , Fan Chun , Sun Ru‐Shu
Published: September 2010

The acyclic precursors. methyl 3‐perfluoroallkyl‐4‐carbethoxy‐5‐methoxy‐6‐(trihenylphosphoranylidene)hexa‐2.4‐dienoates (4) were obtained via the addition reaction of ethyl 3‐methoxy‐4‐(triphenylphosphoranylidene)but‐2‐enoate (2) with equally molar methyl 2‐perfluoroalkynoates (3). Ethyl 2,4‐dimethoxy‐6‐perfluoroalkylbenzoates (5) were synthesized in high yield via an intramolecular elimination of Ph3PO of 4 by heating in anhydrous benzene in a sealed tube. The structure of these compounds was confirmed by IR, 1H, 13C, 2D C‐H cosy NMR and mass spectra and elemental analyses. The possible reaction mechanisms were also proposed.
Novel synthesis of 1,2,3‐Triazoles via 1,3‐dipolar cycloadditions of alkynes to azides in ionic liquid
Authors: Zhong Ping , Guo Sheng‐Rong
Published: September 2010

2‐Azido‐3,5‐dichloropyridine and 2‐azido‐5‐chloro‐3‐fluoropyridine were given by reaction of sodium azide with 2,3,5‐trichloropyride, 3,5‐dichloro‐2‐fluoropyriridine or 5‐chloro‐2,3‐difluoropyridine in ionic liquids. 1,3‐Dipolar cycloaddition of 2‐azido‐3,5‐dichloropyridine or 2‐azido‐5‐chloro‐3‐fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5‐trisubstituted [1,2,3]‐triazoles in good yields and regioselectivities.
Chemoselective dehydrogenation of 3‐[2‐(3,4=Dihydro‐1‐naphthalenyl)ethyl]imidazolidine‐2,4‐diones: A new and convenient synthesis of 13,16‐diazaequilenin analogs
Authors: Parihar J. A. , Ramana M. M. V.
Published: September 2010

The synthesis of the title compounds starting with the chemoselective dehydrogenation of 3‐[2‐(3,4‐dihydro‐naphthalenyl)ethyl]imidazolidine‐2,4‐diones has been described.