Efficient Syntheses of 2-Substituted Benzimidazoles and Benzoxazoles from β-Keto Esters

An efficient synthetic method was developed to synthesize 2-substituted benzimidazoles and benzo- xazoles with β-keto esters as starting materials under mild reaction conditions, during which other functional groups are bearable from reactants to products.

STUDY ON THE POLYMERIZATION KINETICS AND STABILITY OF P(UA)/MMA MICROEMULSION

Urethane acrylate anionomer (APUA) as a kind of new type polymerizable emulsifier was synthesized using 2,4-toluene diisocyanate (TDI), polypropylene glycol (PPG), 2-hydroxyethyl methacrylate (HEMA) and dimethylolpropionic acid (DMPA). The critical micelle concentration (CMC) of APUA was measured by the methods of conductance and surface tension. The comparative studies between polymerizable emulsifier AUPA and conventional emulsifier sodium dodecyl sulfate (SDS) were carried out in the emulsion polymerization of methyl methacrylate (MMA). Polymerization kinetics, stability, size and morphology of the latex particles were investigated. It was found that in APUA both water soluble initiator potassium persulfate (KPS) and oil soluble initiator 2,2'-azobisisobutyronitrile (AlBN) can start the reaction of MMA, and the polymerization rate and yield were very high. On using AlBN as an initiator, the conversion-time behavior of MMA with APUA as emulsifier was different to that of SDS as emulsifier, signifying a different nucleation mechanism of the polymer latex particle. The average size of the two kinds of particles is about 50 nm. The particle size decreases with increasing emulsifier concentration. On using KPS as the initiator, APUA as emulsifier, cross-linking hydrogel of PMMA would be formed, but SDS was used as emulsifier and the hydrogel of PMMA was not present.

Synthesis and Structure of N-(E)-Enoyl(-)-bornane-10,2-sultams

Two potential chiral auxiliaries, N (E ) enoyl(-) bornane 10,2 sultams, were synthesized from (-) bornane 10,2 sultams. The molecular crystal structures of the title compounds were determined by diffraction analysis. The crystal of C 16 O 3SNH 25 belongs to a rhombic system, the space group is P 2 12 12 1 with cell parameters: a =0 734 6(7) nm, b =1 142 7(3) nm, c =2 009 7(3) nm, β =90 00°, V =1 686 9 nm 3, Z=4, D c=1 250 g/cm 3, μ =1 926 cm -1 and F (000)=672. The crystal of C 15 O 3SNH 23 belongs to a rhombic system, the space group is P 2 12 12 1 with cell parameters: a =0 738 2(2) nm, b =0 921 6(1) nm, c =2 280 9(8) nm, β =90 00°, V =1 551 7 nm 3, Z =4, D c=1 273 g/cm 3, μ =2 504 cm -1 and F (000)=640. The structural characteristics with respect to the potential utility for the stereoselective Michael addition reaction of the N enoyl group are discussed.

Stereoselective Synthesis of the Pheromones of Ant Tetramorium Impurm and Leptogenys Diminuta

( 3R,4S )-4-Methyl-3-hexanol and ( 3R,4S )-4-methyl-3-heptanol, which are the pheromones of ant Tetramorium impurm and Leptogenys diminuta , were stereoselectively synthesized by six step sequence starting from N bornane 10,2 sultam separately, the two asymmetric carbon atoms of the target products were created by employing asymmetric syn aldolization of N acylbornane 10,2 sultam with propylaldehyde. The enantiomeric excess of the target products prepared by this route is over 92%.

Addition of Allyltrimethylsilane to tert-Butanesulfinyl Imines Triggered by Tetra-n-butylammonium Fluoride

The addition of allyltrimethylsilane to tert-butanesulfinyl imines triggered by tetra-n-butylammonium fluoride （TBAF） in the presence of 4A molecular sieves has been studied, and homoallylsulfinamides were obtained in good yields with moderate to high diastereoselectivities.

Synthesis of the Stereoisomers of the Sex Pheromones of the Southern Corn Rootworm

A simple and efficient asymmetric synthesis of the sex pheromone of the southern corn rootworm is discribed. The key step is the asymmetric Michael addition of enoylsultam with virtually complete asymmetric induction( e.e. %>99%)

Microwave-Assisted Soluble Polymer-supported Synthesis of Peptoids

Libraries of peptide-like compounds are attractive sources of binding agents for proteomics applications. The synthesis of oligomeric combinatorial libraries of peptidomimetics is usually more straightforward than the creation of large libraries of more "drug-like" molecules. Herein we report synthesis of peptoids on soluble high loading Noncross-linked polystyrene. The synthesis route consists of: (a) preparation "soluble wang resin" from non-crosslinked polystyrene and 4-hydroxybenzyl alcohol via ether linkage, (b) an esterification step performed by the addition of bromoacetyl bromide to "soluble wang resin" and (c) a nucleophilic displacement of bromide with a primary amine.……

Soluble Polymer-Supported Synthesis of α-Amino Acid Derivatives

Due to the central role played by α-amino acid in chemistry and biology, the development of versatile and new methodology for the synthesis of natural and unnatural α-amino acid has emerged as an important and challenging synthetic endeavour for organic chemists.[1] Among the various methodologies reported for α-amino acid synthesis, [2,3] the solid-phase organic synthesis (SPOS) has served as an important approach. [4] However, inherent prob lems on solid supports are reactive site accessibility, site-site interaction and monitoring of the reaction.……

Chemical Compositions and Distribution Characteristics of Cements in Longmaxi Formation Shales, Southwest China

Shale gas resources have been regarded as a viable energy source, and it is of great significance to characterize the shale composition of different cements, such as quartz and dolomite. In this research, chemical analysis and the multifractal method have been used to study the mineral compositions and petrophysical structures of cements in shale samples from the Longmaxi Formation, China. X-ray diffraction, electron microprobe, field emission scanning electron microscopy, cathodoluminescence microscopy and C-O isotope analyses confirmed that cements in the Longmaxi Formation shales are mainly composed of Fe-bearing dolomite and quartz. Fe-bearing dolomite cements concentrate around dolomite as annuli, filling micron-sized inorganic primary pores. Quartz cements in the form of nanoparicles fill primary inter-crystalline pores among clay minerals. Theoretical calculation shows that the Fe-bearing dolomite cements formed slightly earlier than the quartz cements, but both were related to diagenetic illitization of smectite. Moreover, multifractal analysis reveals that the quartz cements are more irregularly distributed in pores than the Fe-bearing dolomite cements. These results suggest that the plugging effect of the quartz cements on the primary inoraganic pore structures is the dominant factor resulting in low interconnected porosity of shales, which are unfavorable for the enrichment of shale gas.

Organic-inorganic Hybrid Materials Based on Molybdophosphate and Organic Polyammonium

A new organic-inorganic hybrid compound （dienHs）2（P2Mo5O23） （1） [dien=NH（CH2CH2NH2）2] has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, thermogravimetric analysis, and the single crystal X-ray diffraction technique. Compound 1 crystallizes in the triclinic system with space group P1 and a=0.9790（2） nm, b=0.9922（2） nm, c= 1.4644（3） nm, α=95.510（10）°, β=98.860（10）°, γ=95.700（10）°, V=1.3895（5） nm^3, Z=2, R=0.0465. The results show that the compound consists of dienH3^3＋＋ and P2Mo5O23^6-, and the heteropoly anion P2Mo5O23^6- is connected to a 1-D chain structure with the protonated dien by hydrogen bonds.

Synthesis and Investigation of Soluble Polymer-supported Dendrimers

Poly（ethylene glycol） （PEG）-supported dendrimers have been synthesized using 2.4,6-trichloro-1,3,5-triazine （TCT） as dendrons and tris（hydroxymethyl）aminomethane as tinkers with high loading capacity, excellent solubility and thermal stability by divergent method. The new synthesized PEG-supported G2.0 dendrimer has 10 times as large functional group loading capacity as commercial PEG3400 with overall yield 44.0%.

Construction of Two Chiral Bilayer Coordination Polymers Based on 2-（Pyridine-3-yl）-lH-4,5- imidazoledicarboxylate Ligand

Two novel isomorphic coordination polymers [Zn（HPyImDC）H20]（1） and [Co（HPylmDC）H20]（2） were synthesized from 2-（pyridine-3-yl）-lH-4,5-imidazoledicarboxylic acid（H3PylmDC） under hydrothermal conditions. Both the compounds crystallized in P21221 chiral space group, possessing left-hand helical chains and right-hand helical chains. Two types of helical chains connected with each other to form an interesting 2D bilayer structure which extended to a 3D supermolecular structure via the hydrogen-bonding interactions. Topology analysis shows that H3PylmDC ligand and metal center can be regarded as 3-connected T-shaped nodes, thus leading to a （3,3）- connected network with vertex symbol of （82.10）.

Catena-dichloro(4,4′-dimethyl-2,2′-bipyridine)Cadmium(Ⅱ),a New One-dimensional Chain with Blue Fluorescent Emission

A new μ-chloro-bridged one-dimensional coordination polymer [Cd（dmbpy）Cl2]a （dmbpy = 4,4＇-dimethyl-2,2＇-bipyridine） has been synthesized and structurally characterized by elemental analyses, IR, UV spectra and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group C2/c with a = 17.745（4）, b = 10.326（2）, c = 7.3382（15）A, β = 106.85（3）°, V = 1286.9（4）A^3, Z = 4, C12H12N2Cl2Cd, Mr = 367.54, Dc = 1.897 g/cm^3, F（000） = 720, 2（MoKα） = 0.71073 A,μ= 2.089 mm^-1, R = 0.0368 and wR = 0.1048 for 1041 observed reflections （I 〉 2σ（I））. Cadmium（Ⅱ） adopts a distorted octahedral coordination geometry and adjacent coordination chains are intercalated in a zipper-like fashion into 2D layers through the π-π stacking interactions between dmbpy. Fluorescent analyses show that it exhibits intense blue photoluminescence in both DMF and DMSO solutions at room temperature.

Novel Synthesis of N-Substituted p-Hydroxybenzoic Amides on Soluble Polymer-Support

The synthesis of N -substituted p -hydroxybenzoic amides using a liquid phase approach is described. Poly(ethylene glycol) (PEG) and p -hydroxybenzoic acid were linked by oxalyl chloride to give compound 1,which was chlorinated by thionyl chloride,followed by amidation with NHR 1R 2 to yield compound 3. Hydrolysis of compound 3 gave the title amide 4. These crude library members were obtained in good yields with high purities.

Magnetic Co_3O_4 nanowires,preparation and properties

The Co3O4 nanowires have been successfully synthesized via modified template method.The as-prepared products have been characterized by EDS,TEM and HRTEM analysis.The magnetic behavior of it is investigated by a magnetic property measurement system.The nanowires exhibit some novel magnetic properties,which are different from its bulk material.The temperature dependence curves of magnetization in zero-field-cooling and field-cooling exhibit two peaks of antiferromagnetic at blocking temperature of～23 K and～31 K,respectively.The field dependent M（H） curves of the Co_3O_4 nanowires at T = 5 and 300 K both exhibit PM properties.Moreover,the diameter of nanowires is hence determined according to the finite size effect as approximately 7-11 nm,in consistent with the characterizations by HRTEM.

Porous cobalt oxide nanowires: Notable improved gas sensing performances

The porous Co3O4 nanowires have been successfully synthesized via modified template method. A possible growth mechanism governing the formation of such 1D nanowires is proposed. The as-prepared products have been characterized by X-ray Powder Diffraction (XRD), Extended X-ray Absorption Fine-structure (EXAFS), High-resolution Transmission Electron Microscopy (HRTEM) and N2 adsorption/desorption analysis. Our systematic studies have revealed that the porous Co3O4 nanowires show excellent gas sensing performances, which demonstrate the potential application of the 1D nanostructured Co3O4 in the detection of the ethanol gas as a sensor material. The improved performances are owing to its large specific surface area and porous morphology.

Mesoporous cobalt oxide for largely improved lithium storage properties

We report the microstructure, application for lithium-ion batteries of mesoporous Co304 prepared by modified KIT-6 template method. The sample was characterized by XRD, TEM, HRTEM and nitrogen adsorption. Their electrochemical behaviors as electrode reactants for lithium ion batteries were evaluated by cyclic voltammograms and static charge-discharge. A direct comparison of electrochemical behaviors between mesoporous nanostructure and bulk reflects interesting ＂nanostructure effect＂, which is reasonably discussed in terms of how the 3D nanostructures of Co3O4 materials function in tuning their electrochemistry. The results demonstrate that further improvement of electrochemical performance in transition metal-oxide-based anode materials can be realized via the design of multiporous nanostructured materials.

Surface engineering towards high-energy carbon cathode for advanced aqueous zinc-ion hybrid capacitors

Opportunities coexist with challenges for the development of carbon-based cathodes with a high energy density applied for zinc ion hybrid capacitors(ZIHCs).In the present study,a facile and effective surface engineering approach is demonstrated to greatly improve the energy storage ability of commercial carbon paper(CP)in ZIHC.Benefiting from the introduced oxygen functional groups,larger surface area and improved surface wettability upon air calcination,the assembled aqueous ZIHC with the functionalized carbon paper(FCP)exhibits a much higher areal capacity of 0.22 mAh/cm^(2)at 1 mA/cm^(2),outperforming the counterpart with blank CP by over 5000 times.More importantly,a superior energy density and power density of 130.8μWh/cm^(2)and 7460.5μW/cm^(2),are respectively delivered.Furthermore,more than 90%of the initial capacity is retained over 10000 cycles.This surface engineering strategy to improve the energy storage capability is potentially applicable to developing a wide range of high-energy carbon electrode materials.