A novel phosphorus‐containing thermotropic liquid crystalline poly(ester‐imide) with high flame retardancy

A novel phosphorus–nitrogen thermotropic liquid crystalline poly(ester‐imide) (PN‐TLCP) derived from p‐acetoxybenzoic acid (ABA), terephthalic acid (TPA), acetylated 2‐(6‐oxide‐6H‐dibenz<c,e><1,2>oxa phosphorin‐ 6‐yl)‐1,4‐dihydroxy phenylene (DOPO‐AHQ) and N,N'‐hexane‐1,6‐diylbis(trimellitimide) was prepared by melt transesterification. The chemical structure, the mesophase behavior, and the thermal properties of the copolymer were investigated with Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹H NMR), elemental analysis, wide‐angle X‐ray diffraction (WAXD), hot‐stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). PN‐TLCP exhibited a nematic mesophase with a strong birefringence at a low and broad mesomorphic temperature ranging from 220 to 350°C, an initial flow temperature as low as about 190°C and a glass transition temperature of about 160°C. PN‐TLCP has also good thermal stability, high char residues and excellent flame retardancy (limiting oxygen index, LOI = 71 and UL‐94 V‐0 rating). Copyright © 2009 John Wiley & Sons, Ltd.     

Impact of fluorine on the phase behavior of bis-p-tolyl propane in supercritical CO2, 1,1-difluoroethane,and 1,1,1,2-tetrafluoroethane

Fluorine substitution on a solute can have a significant effect on solute solubility in a given solvent and fluorine substitution on a solvent can also have a significant effect on solvent quality. The effect of fluorine is demonstrated with the phase behavior data for bis(p-tolyl)propane (BTP) compared to bis(p-tolyl)hexafluoropropane (BTHFP) in supercritical carbon dioxide, 1,1-difluoroethane (F152a), and 1,1,1,2-tetrafluoroethane (F134a). Semifluorinated BTHFP is more soluble than non-fluorinated BTP in all three solvents, especially CO₂. The CO₂–BTP system exhibits solid solubility behavior while the CO₂–BTHFP system exhibits liquid–liquid–vapor (LLV) behavior near the critical point of CO₂. Although the two dipolar hydrofluorocarbons (HFC) are better solvents than CO₂ for these two aromatic solid compounds, F152a is the superior HFC solvent, especially for BTP, because F152a has a smaller molar volume and a larger effective dipole moment than F134a. LLV behavior is also observed for the F134a–BTP system near the critical point of F134a although the F134a–BTHFP, F152a–BTP, and F152a–BTHFP systems all appear to exhibit type-I phase behavior and no liquid–liquid immiscibility near the respective critical points.     

Constructing 2D Sandwich-like MOF/MXene Heterostructures for Durable and Fast Aqueous Zinc-Ion Batteries

Two-dimensional metal–organic frameworks (2D MOFs) can be used as the cathodes for high-performance zinc-ion battery due to their large one-dimensional channels. However, the conventionally poor electrical conductivity and low structural stability hinder their advances. Herein, we report an alternately stacked MOF/MX heterostructure, exhibiting the 2D sandwich-like structure with abundant active sites, improved electrical conductivity and exceptional structural stability. Ex situ characterizations and theoretical calculations reveal a reversible intercalation mechanism of zinc ions and high electrical conductivity in the 2D heterostructure. Electrochemical tests confirm excellent Zn²⁺ migration kinetics and ideal pseudocapacitive behaviors. As a consequence, Cu-HHTP/MX shows a superior rate performance (260.1 mAh g⁻¹ at 0.1 A g⁻¹ and 173.1 mAh g⁻¹ at 4 A g⁻¹) and long-term cycling stability of 92.5 % capacity retention over 1000 cycles at 4 A g⁻¹.     

Generation of Glycosyl Radicals from Glycosyl Sulfoxides and Its Use in the Synthesis of C‐linked Glycoconjugates

We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available, air and moisture stable precursors to glycosyl radicals. These glycosyl sulfoxides could be converted to glycosyl radicals by way of a rapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex C‐linked glycoconjugates under mild conditions. This reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate‐DNA conjugates.     

Synthesis and Characterization of 2-[(3-Aminophenyl)sulfonyl] ethanol Hydrogen Sulfate

2-[(3-Aminophenyl)sulfonyl] ethanol hydrogen sulfate (APSES) is an important intermediate for reactive dyes.It can be used to synthesize KN type reactive dyes, which have broad colour spectra,good water solubility, excellent adaptability for different dye technique,etc. Synthesis of APSES were currently developed by Kato Kuniok et al^[1] and Sanki^[2].Kato had attempted to synthesize of APSES by reaction of sodium benzenesulfinate as raw material with ethylene oxide to obtain 2-phenylsulfonyl ethanol(PSE). The PSE could further be nitrated and hydrogenated to obtain 2-[(3-aminophenyl)sulfonyl]ethanol (APSE). Finally,APSE was reacted with oleum to obtain 2-[(3-aminophenyl) sulfonyl] ethanol hydrogen sulfate (APSES). Sanki had discoved a new synthetic method for the PSE. The PSE was prepared by first reaction of thiophenol as raw material with chloroethanol, and then by oxidation with hydrogen peroxide.The above mentioned two methods are not easily be adopted in industries at home. The shortage and cost of the thiophenol and sodium benzenesulfinate are mainly limited. We modificated a new synthetic pathway for APSES by five steps. The experimental procedures are shown the following.     

蜂王信息素的改进合成

早在50年代,Butler等^[1]发现蜂王的上颚腺能分泌一种影响工蜂活动的物质,并提出了蜂群是靠蜂王分泌的该种化学物质传递各种个体间的信息的论断,Barbier等^[2]测定其结构为9-氧代-2E-癸烯酸1(蜂王物质),并首次进行了人工合成.     

"Click" synthesis of small molecule probes for activity-based fingerprinting of matrix metalloproteases

By using "Click Chemistry", we achieved the facile synthesis of various affinity-based hydroxamate probes that enable generation of activity-based fingerprints of a variety of metalloproteases, including matrix metalloproteases (MMPs), in proteomics experiments.     

Beta-isocupreidine-catalyzed Baylis-Hillman reaction of chiral N-boc-alpha-amino aldehydes

[Structure: see text] Beta-isocupreidine (beta-ICD)-catalyzed Baylis-Hillman reaction of chiral N-Boc-alpha-amino aldehydes and 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) takes place without racemization and exhibits the match-mismatch relationship between the substrate and the catalyst. In the case of acyclic amino aldehydes, L-substrates show excellent syn selectivity and high reactivity in contrast to D-substrates. On the other hand, in the case of cyclic amino aldehydes, D-substrates rather than L-substrates show excellent anti selectivity and high reactivity.     

A new cytotoxic 2-（2-phenylethyl）chromone from Chinese eaglewood

A new compound 8-chloro-5,6,7-trihydroxy-2-（3-hydroxy-4-methoxyphenethyl）-5,6,7,8-tetralaydro-4H-chromen-4-one （1） was isolated from the Chinese eaglewood [Aquilaria sinensis （Lour.） Gilg]. Its structure was elucidated on the basis of spectral data. Compound I showed cytotoxicity against human gastric cancer cell line （SGC-7901） in vitro by MTT method with the IC50 value of 14.6 μg/mL.